United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R05-88/065
March 1988
SEPA
Superfund
Record of Decision
South Andover, MN
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50273-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R05-88/065
3. Recipient's Accession No.
4. Title end Subtitle
SUPERFUND RECORD OF DECISION
South Andover, MN
st Remedial Action
5. Report Oete
03/30/88
jthorfs)
8. Performing Organization Rept. No
9. Performing Organization Neme and Address
10. Project/Task/Work Unit No.
11. Contract(C) or Grant(G) No.
(C)
(G)
12. Sponsoring Organization Neme and Address
U.S. Environmental Protection Agency
4U1 M Street, S.W.
Washington, D.C. 20460
13. Type of Report & Period Covered
800/000
u.
13. Supplementary Notes
16. Abstract (Limit: 200 word*)
The South Andover site is comprised of several separate parcels of land totaling
approximately 50 acres in the southern portion of Andover, Minnesota. One-quarter, mile
to the north of the site is a residential neighborhood. Further development, is planned
to the west and the south of the site. A large portion of the site is buried under a
pile of tires and miscellaneous junk. Several smaller pieces of property on the site
are auto salvage yards. The Waste Disposal Engineering landfill, a Superfund National
crities List site, is located 3,000 feet northeast of South Andover. Multiple waste
..idling operations occurred between 1954 and 1981 on several properties within the site
boundaries. Consequently, there are multiple source areas which include a drum storage
area, a waste discharge area, and a waste burning area. In 1976, citizen complaints of
well contamination prompted the Minnesota Pollution Control Agency (MPCA) to investigate
the site and issue a Citation of Violation for the storage of chemical waste. Waste
processing was discontinued in early 1977, and waste acceptance ceased in 1978. In
1980, the MPCA issued Notices of Violation for improper disposal of industrial wastes.
In 1981, the contents of approximately 700 drums were disposed of by mixing them with
waste oil and using the mixture as fuel. In 1986, a group of PRPs removed approximately
500 additional onsite drums. Soil investigations have been limited by the presence of a
(See Attached Sheet)
17. Document Analysis a. Descriptors
Record of Decision
South Andover, MN
First Remedial Action
Contaminated Media: gw
Kay i
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EPA/ROD/R05-88/065
South Andover, MN
First Remedial Action
16. ABSTRACT (continued)
large volume of tires piled onsite and piles of junked automobiles. The majority of the
tires are currently being shredded and removed from the site. A subsequent RI/FS for
soils and the lower sand aquifer is planned following tire removal. Currently, the
primary contaminants of concern affecting the ground water include: arsenic, chromium,
lead, metals, VOCs, PCE, TCE, toluene, and organics.
The selected remedial action for this site includes: continuous ground water
extraction; provision of municipal water to private well users on or near the site;
ground water monitoring; and placement of restrictions on new wells on or near the
site. The present worth cost for this remedial action ranges from £920,000 to
|>2,460,000 depending on the discharge option selected. Present worth O&M ranges from
£21,000 to £140,000.
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RECORD OF DECISION '
INITIAL GROUNDWATER OPERABLE UNIT
SITE NAME AND LOCATION
South Andover
Andover, Minnesota
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for the South
Andover site developed in accordance with the Comprehensive Environmental
Response, Compensation, and Liability Act of 1980, 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.
tfiis decision is based upon the contents of the administrative record for the
South Andover site.
The State of Minnesota concurs with the selected remedy.
DESCRIPTION OF THE REMEDY
This initial groundwater operable unit was developed to protect public health
and the environment by controlling the migration of contaminants present in
the surficial aquifer. The operable unit is fully consistent with all planned
future site activities. Future site activities include locating contaminant
source areas and developing the overall site remedy.
The major components of the selected remedy are as follows:
- Extract groundwater from the surficial aquifer;
- Provide municipal water to private well users on or near the site;
- Monitor groundwater movement at the site; and
- Place restrictions on new wells on or near the site.
DECLARATION
The selected remedy is protective of human health and the environment, will
attain the applicable or relevant and appropriate requirements of other
Federal and State environmental laws and is cost effective.
This remedy utilizes permanent solutions and alternative treatment
technologies to the maximum extent practicable for this action. However,
because this action will not difinitively address any potential contaminant
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-2-
source areas, due to its limited scope of migration control, this remedy
does not satisfy the statutory preference for treatment as a principal
element. Subsequent actions are planned for the site that will address all
remaining concerns.
Date
Valdas V. Adamkus; 7
Regional Administrator
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SUWARY OF REMEDIAL ALTERNATIVE SELECTION
SOUTH ANDOVER SITE
GROUNDWATER OPERABLE UNIT
SITE LOCATION AND DESCRIPTION
The South Andover site is located in the southern portion of Andover,
Minnesota, approximately 16 miles north - northeast of Minneapolis. The
site is located in the southern half of Section 34 of Grow Township
(T.32N., R.24W.). The South Andover site vicinity is shown in Figure 1.
A residential neighborhood exists 1/4 mile north of the site.
Development is currently planned to the west and the south of the site.
Bunker Lake Boulevard borders the site on the north, and Jay Street on
the east. Small businesses along both roads deal in used cars, auto
parts, and auto salvage. Several pieces of property within the site are
auto salvage yards, and a large portion of the site is buried under a
pile of tires and miscellaneous junk. The Waste Disposal Engineering
landfill (WOE), which previously accepted hazardous waste, is located
3,000 feet northeast of the site. WOE is a National Priorities List site
which is undergoing remedial design.
The site is comprised of several separate parcels of land totaling
approximately 50 acres. Various independent storage and disposal
activities took place on the site. The parcels of land are shown in
Figure 2. The waste storage and disposal activities are detailed in
Table 1.
SITE HISTORY
Industrial waste handling activities at the South Andover site are
reported to have begun in 1954 with the storage of solvents and inks on
the Cecil Heidelberger property. Open pit burning of liquid wastes began
on the Batson property in 1970. Chemical waste storage began at the
Mistelske property in 1973.
Actions to limit the waste handlers at the various properties began in
1973 when Anoka County officials instructed Cecil Heidelberger to remove
and dispose of the chemical wastes stored on the property. Citizen
complaints of well contamination prompted investigations by the Minnesota
Pollution Control Agency (MPCA). MPCA issued a Citation of Violation to
Cecil and Marion Heidelberger in 1976 for the storage of chemical waste.
The Heidelbergers discontinued processing waste in early 1977 and stopped
accepting waste in 1978.
Actions to regulate other waste handlers at the site occurred in 1980.
Notices of Violation were issued by the MPCA to Shirley Heidelberger,
Cyril Link, and Charles Mistelske for improper disposal of industrial
wastes.
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a ~°
WASTE DISPOSAL
ENGINEERING
LANDFILL
\^nl
I Minnesota/
) f Sootl
l *fAndov
\Ue
2000
R24fo
4000
South
Andover
Scale in Feet
FIGURE 1
LOCATION OF SOUTH ANDOVER SITE
SOUTH ANOOVER
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TABLE 1
WASTE LOCATION AND DISPOSAL ACTIVITY
LOCATION
Cecil Heidelberger
Property
Batson Property
Charles Mistelske
Property
Meyer Property
Klar Property
DISPOSAL ACTIVITY
Chemical wastes were stored and disposed of
on the property. A majority of the property
is covered with tires and other debris.
Thousands of barrels of solvents and inks
were allegedly burned in open pits. A
wetland on the property was used as a
disposal area prior to filling.
The property was used to store approximately
8,300 gallons of paints, adhesives and
greases in 1-,2-,'and SB-gallon containers.
The property was used to store approximately
200 drums of chemical waste. Spillage of
chemical waste is known to have occurred.
Storage of drummed waste and transformers
occurred on the property.
An inactive smelting plant, empty drums and
miscellaneous debris are present on the site.
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Cecil Heidelberger disposed of the contents of approximately 700 drums in
1981 by mixing the contents with waste oil and using the mixture as fuel
in an asphalt plant. Approximately 500 additional drums were removed in
1986 by a group of potentially responsible parties (PRPs). Some drums
remain onsite.
Several site investigations have been performed at the site. An initial
appraisal was performed by Residual Management Technologies (RMT) and
PEDCo Environmental in 1979 at the request of U.S. EPA. A follow-up
investigation by RMT/PEDCo in 1981 included the installation of 22
monitoring wells. Ecology & Environment, Inc. (E&E) installed 26
additional wells and 22 piezometers in 1981 as part of an expanded FIT
groundwater investigation.
An initial remedial investigation (RI), completed January 29, 1988, was
performed at the site to characterize the nature and extent of
contamination. Soil investigations were limited by the presence of a
large volume of tires piled onsite and piles of junked automobiles at
various auto salvage yards onsite. The tires on the Cecil Heidelberger
property, the majority of the tires, are currently being shredded and
removed from the site under a grant from the Minnesota Waste Management
Board. The tire removal is scheduled to be completed by Spring 1989. A
subsequent RI, looking at contamination of site soils and possible
contamination of the lower sand aquifer, is planned for the site
following the tire removal.
A feasibility study (FS), completed January 29, 1988, was developed in
conjunction with the RI. The FS looked at a variety of alternatives for
dealing with the groundwater problem. The alternatives ranged from no
action to complete lateral containment of the surficial aquifer with
groundwater extraction.
ENFORCEMENT HISTORY
Sixteen parties were notified, by a March 15, 1982 letter from U.S.EPA's
Office of Enforcement and Compliance Monitoring (OECM) in Washington,
that the U.S. EPA was considering spending public funds at the South
Andover site and that they may be liable for money expended by the
government. These parties included site owners, site operators and waste
generators.
In a July 30, 1985 letter from U.S. EPA Region V, 21 PRPs were notified
that U.S. EPA planned to conduct an RI/FS at the site, and that the U.S.
EPA would consider an offer by the PRPs to conduct the RI/FS. None of
the PRPs indicated that they had the desire and ability to conduct the
RI/FS. Negotiations were terminated in an August 29, 1985 memorandum,
and the Superfund was used to conduct the RI/FS.
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Copies of the Proposed Plan for this operable unit were sent to the PRPs
on February 1, 1988. In a February 26, 1988 letter from U.S. EPA Region
V, 21 PRPs were notified that the U.S. EPA intended to conduct a remedial
action at the site and that the PRPs had 60 days to submit a good faith
proposal. No response has been received as of this date.
COWUHITY RELATIONS HISTORY
Community relations activities at the South Andover site have been
handled with direct involvement from the U.S. EPA and the MPCA. The
initial contact with the public was in the form of interviews with
representatives of the City of Andover, City of Coon Rapids and property
owners on or near the site.
Two public meetings have been held for the site. The first meeting was
held on September 25, 1985 prior to initiating field activities. The
second meettrrg was held on February 8, 1988 to answer questions and
receive comments on this initial groundwater operable unit.
Public involvement and participation on the site has been limited to
date. Representatives of the City of Andover and Anoka County have asked
for greater involvement. There is a strong interest from these local
bodies to facilitate development of the site and the surrounding area.
Concern has also been expressed regarding the impact of this site when
combined with the presence and remedial actions planned for the WOE site.
SCOPE OF OPERABLE UNIT
This response action is an initial groundwater operable unit and is
consistent with Section 300.68(c) of the National Contingency Plan (NCP).
This initial groundwater operable unit is being implemented to protect
public health and the environment by controlling the migration of
contaminated groundwater. The operable unit addresses known areas of
groundwater contamination in the surficial aquifer. The U.S. EPA and
MPCA feel the possible migration of contaminants from the surficial
aquifer off the site or into the lower aquifer are the major concern
posed by the site.' This operable unit was initiated to deal with these
concerns.
The operable unit is fully consistent with all future site work,
including the subsequent RI/FS planned for Spring 1989. In addition, it
is believed that the gradients established by the extraction well system
may be beneficial to the subsequent RI by aiding in the location of "hot
spots" which have not been detected. The extraction well system will be
incorporated into any subsequent remedial action decisions at the site.
*t was determined that the soils do not pose a risk which needs to be
addressed as part of the present operable unit. A subsequent RI/FS is
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planned for the site following the tire removal presently scheduled to be
completed by Spring 1989. Because the soil investigation has not been
completed, it was determined that soil removal or capping at the present
time could interfere with the subsequent RI/FS, may not be consistent
with the final remedy and may not be cost effective. For these reasons,
an interim soil remedy was determined to be unnecessary and inappropriate
at the present time.
SITE CHARACTERISTICS
The initial RI focused on the
which were clear of tires and
broken down into three areas:
water and sediments.
surficial aquifer and portions of the site
other debris. The results of the RI can be
1) groundwater, 2) soils, and 3) surface
Multiple waste handling operations occurred between 1954 and 1981 on
several different properties within the general site boundaries. Because
of this, there is not one source area, but multiple source areas which
include locations where drums were stored, where wastes were discharged
to- the ground, and where wastes were allegedly burned.
As a part of the.initial RI, potential risks from contaminated
groundwater and exposed soil locations on the site were calculated based
on present site use conditions and on possible future residential or
commercial development conditions. Both carcinogenic
risks were calculated. Risks were not calculated for
sediment locations at this time, but will be included
RI.
and noncarcinogenic
surface water and
in the subsequent
The carcinogenic risks are theoretical quantifications, and are reported
as excess lifetime cancer risks. Excess lifetime cancer risk is defined
as the incremental increase in the probability of getting cancer compared
to the probability if no exposure occurred. For example, a lxlO~6 excess
lifetime cancer risk represents an exposure that could result in one
extra cancer case per million people exposed. Noncarcinogenic risks are
determined by comparing potential doses of contaminants by site visitors
to contaminant specific reference doses. The reference dose is an
estimate of an exposure level that would not be expected to cause
adverse effects when exposure occurs.
The analytical results from the remedial investigation and the risk
assessment can be found in the RI Report for the South Andover site
completed January 29, 1988. A brief summary of the results is presented
below.
Groundwater Contamination
The site is underlain by a surficial sand aquifer, a middle aquitard, a
lower sand aquifer, a till unit and a bedrock aquifer. The lateral flow
in the surficial aquifer was found to radiate->in a generally .wes.twardly .
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direction from the eastern portion of the site. Water level measurements
in the well nests indicate a dominant downward component of flow in both
the surficial aquifer and the middle aquitard. Residence time of
groundwater in the surficial aquifer and the aquitard are less than 10
years and 28 to 70 years respectively. The potentiometric surface of the
lower sand aquifer indicates lateral flow southwest across the site.
Groundwater samples were collected from 50 monitoring wells and 8
residential wells on or near the site. Elevated levels of a number of
organic and inorganic compounds were detected in shallow monitor wells on
site. The highest detected contaminant concentrations are shown in Table
2. Only one contaminant was detected in the lower sand aquifer, and it
was only detected in one well which contained 97 ppb methylene
chloride. The methylene chloride may be a lab contaminant as opposed to
actually being present in the well. Additional RI work is "planned for
the lower sand aquifer. Residential well sampling by Anoka County and
the MPCA indicated that one residential well on-site, which was drawing
from the surficial aquifer, was found to be contaminated. This well was
ordered to be abandoned by the MPCA.
The contaminants are found in zones of discrete contamination rather than
in a continuous plume. This is indicative of the multiple waste handling
and disposal operations which occurred on the site.
The contaminated surficial aquifer exceeds a number of maximum
contaminant levels as set by the Safe Drinking Water Act and pose
incremental cancer risks of greater than lxlO~^. The groundwater does
not pose an imminent risk to the population because the upper aquifer is
not currently used as a -source of drinking water on or near the site.
However, because there is a downward gradient through the aquifer
separating the upper and lower sand aquifers, the upper sand aquifer is a
possible source of contamination to the lower sand aquifer which serves
as a regional drinking water source. There is a potential for an
increase in the incremental cancer risk of greater than 1x10"^ if wells
are set in the upper aquifer as a result of future development of the
site or if the lower aquifer becomes contaminated. In addition to the
cancer risk, use of the contaminated groundwater would exceed the
reference dose for bis(2-ethylhexyl)phthalate and acetone.
Soil Contamination
A complete surface and subsurface soil characterization could not be
performed at the site due to the presence of the large volume of tires
and three active auto junk yards. A limited soil sampling was performed
during the RI concentrating on suspected waste storage and disposal areas
which were not buried under tires or automobiles.
The soil samples indicated elevated levels of organics and inorganics.
For the most part, each contaminant was found at low levels and in a
limited number of locations. Under current land use the incremental
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TABLE 2
CONTAMINANT LEVELS AND STANDARDS
COMPOUND
1,1,1-Trichloroethane
1,1,2-Trichloroethane
1,1-Dichloroethane
1,2-Dichloroethane
1,1-Dichloroethene
1,2-Dichloroethylene
2-Hexanone
4-Methyl-2-Pentanone
Acetone
Chlorobenzene
Ethyl benzene
Methylene Chloride
Tetrachloroethylene
Toluene
Trichloroethylene
Vinyl Chloride
Xylenes
Benzoic Acid
Bis(2-Ethylhexyl)Phthalate
Diethyl Phthalate
Di-n-butyl Phthalate
Di-n-octyl Phthalate
Isophorone
2-Methyl Phenol
4-Methyl Phenol
N-Nitrosodiphenylamine
Phenol
Arsenic
Cadmium
Chromium
Copper
Lead
Nickel
Zinc
HIGHEST
DETECTED
GROUNDWATER
CONCENTRATION
(ug/1)
330
37
12
2
20
9
75
18
170,000
4
18
1600
20
3200
3
12
22
7
ate 2200
1-
24
3
25
21
56
6
6
17
256
127
673
23
168
8120
COON CREEK
30-DAY
AV. DISCHARGE
LIMITS
(ug/1) (e)
830
900
-
2140
-
1880
-
16,970
1,270,000
200
2410
6430
150
1010
1360
86
320
^
10 21
4340 434
-
-
9750
.
_
10
2550
400
-
-
.
220
2720
3060
GROUNDWATER
DRINKING
WATER
STANDARDS
(ug/1)
200 (a)
6.11 (b)
-
3.8 (b)
-
70 (a,b)
-
-
-
60 (b)
680 (a,b)
350 (c)
6.9 (b)
2000 (a.b)
5 (a)
0.15 (b)
440 (a,b)
.
,000 (d)
,000 (d)
-
-
5200 (d)
-
_
71.1'(b)
280 (c)
50 (a,b)
5 (b)
120 (b)
1300 (b)
20 (a,b)
150 (b)
-
POTW
DISCHARGE
LIMITS
(ug/1)
5000 (f)
5000 (f)
10,000 (f)
15,000 (f)
10,000 (f)
10,000 (f)
15,000 (e)
15,000 (e)
15,000 (e)
1000 -(f)
10,000 (f)
15,000 (e)
10,000 (f)
15,000 (e)
10,000 (f)
15,000 (e)
15,000 (e)
15,000 (e)
10,000 (f)
10,000 (f)
10,000 (f)
15,000 (e)
15,000 (e)
15,000 (e)
15,000 (e)
10,000 (f)
15,000 (e)
100 (f)
1000 (f)
10,000 (f)
8000 (f)
100 (f)
1000 (f)
30 (f)
(a) Based on Federal Safe Drinking Water Act Primary Maximum Contaminant
Level
(b) Based on State of Minnesota Recommended Allowable Drinking Water Limits
(c) Based on Federal Office of Drinking Water Health Advisories (Relative
Source Contribution) for long-term exposure (to be considered only)
(d) Based on Federal Clean Water Act Water Quality Criteria for Human Health
adjusted for Toxicity Protection ( to be considered only).
(e) Based on MPCA Division of Water Quality proposed effluent limitation ;
(f) Based on Threshold in inhibitory'effect for activated sludge plants . -
U.S.EPA/530-SW-86-004 (to be considered, orvly}. .-.v; . : - - (/. .:.* -:...J.
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cancer risk posed by the soils is less than lxlO~6. The levels of lead
in three of the soil samples could result in lead intakes which exceed
the reference dose. Under future residential or commercial development,
the cancer risk would exceed lxlO~6. Future use scenarios of light
commercial/industrial development and residential development had
incremental cancer risks of 4x10"^ and 1x10"^ respectively. Under both
of these development scenarios, three soil samples had lead levels which
could result in intakes of lead greater than the reference dose.
Surface Hater and Sediaent Contamination
Six surface water and sediment samples were collected from ponded water
locations on the site. No pesticides or volatile organic compounds were
found in any of the samples. Phenol phthalates and benzoic acid were
detected in the samples. Naphthalene was detected in one sample.
Elevated levels of inorganics were also detected.
The surface water bodies are not used for drinking water or recreation.
Therefore, the surface water and sediments were not dealt with at this
time. They will be considered during the overall site RI/FS.
ALTERNATIVES EVALUATION
The major objective of the feasibility'study (FS) was to evaluate the
need for an initial groundwater measure and possible actions which could
be undertaken. As discussed above, this operable unit will not address
soil remediation. This will be addressed in the subsequent RI/FS. Due
to the limited scope of the RI/FS, which examined the threat to public
health and the environment posed by the contaminated surficial aquifer,
alternatives were formulated to achieve the following four goals:
- Minimize the potential for direct contaminant consumption;
- Control contaminant migration to the lower sand aquifer;
- Control contaminant migration to surface water; and
- Provide measures that will be consistent with the final site
recommendations.
A comprehensive list of appropriate remedial technologies was identified
for groundwater control. These technologies were screened based .on the
characteristics of the site and the characteristics of the contaminants.
The technologies which survived the initial screening were further
screened based on effectiveness, implementability and cost. Cost was
only used between alternative technologies providing similar degrees of
protection and treatment.
Technologies which satisfied the screening requirements were combined to
form remedial action alternatives. Alternatives which could not
guarantee consistency with future site work were dropped from
consideration at this point in the evaluation process. The remaining
alternatives ranged in scope from no action through complete lateral
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containment of the surficial aquifer with groundwater extraction. The
four alternatives developed are detailed below.
Alternative 1 - No Action
The no-action alternative is required by the National Contingency Plan ,
(NCP) to be considered through the detailed analysis. It provides a
baseline for comparison of other alternatives. Under the no-action
alternative, no remedial measures would be undertaken at the South
Andover site at the present time. The choice of the no action
alternative at this time would not affect the U.S. EPA's and the MPCA's
plans to perform a subsequent RI/FS at the South Andover site and is
completely consistent with all future site work.
Alternative 2"- Alternative Mater Supply
The alternative water supply alternative has the following three major
components:
- Provide municipal water to private well users on or near
the site;
- Monitor groundwater movement at the site; and
Place restrictions on new wells on or near the site.
Connection to the municipal water supply would provide uncontaminated
water to residences currently using their own private wells. Municipal
water hookups would be provided to the eight residences sampled during
the RI. Residential wells in both the surficial and lower aquifers will
be properly abandoned to eliminate conduits for future migration of
contaminants into the lower aquifer. This alternative would not affect
future site work.
Groundwater monitoring will be used to detect lateral and vertical
migration of contaminants. The monitoring will be coordinated with
future site investigations. The well restrictions would eliminate the
chance of new wells being installed in a contaminated aquifer.
Alternative 3 - 6roundwater Extraction
The groundwater extraction alternative has the following four major
components:
- Extract groundwater from the surficial aquifer;
- Provide municipal water to private well users on or near
the site;
- Monitor groundwater movement at the site; and
- Place restrictions on new wells on or near the site.
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The extraction wells would be located in or slightly downgradient of
known contaminated groundwater areas. The wells would pump approximately
20 to 50 gpm (total). The extraction well system would control the
horizontal migration of groundwater offsite and limit the vertical
migration of contaminants into the lower aquifer by withdrawing the
contaminated groundwater found in the surficial aquifer. The exact
number and location of the wells will be 'determined during the remedial
design process. Effects on the WDE extraction well system will be taken
into consideration at this time.
The municipal water supply, groundwater monitoring, and restrictions on
wells are the same as described in Alternative 2.
This alternative wi'll not interfere with future site work. In addition,
the gradients imposed by the extraction well system may be helpful in
locating unknown areas of contamination.
Alternative 4 - Lateral Containment
The lateral containment option has the following five major components:
- Install a slurry wall around the site;
Extract groundwater from the surficial aquifer;
Provide municipal water to private well users on or near
the site;
Monitor groundwater movement at the site; and
- Place restrictions on new wells on or near the site.
This alternative incorporates all aspects of Alternative 3 with the
addition of a circumferential slurry wall. The slurry wall will further
limit horizontal groundwater contaminant migration and exclude clean
water recharge from the surrounding aquifer. The entire site would be
surrounded by the slurry wall which would average 30 feet in depth, 3
feet in width, and be approximately 5,800 feet long.
With a reasonable amount of coordination between the development of the
workplan for the subsequent field work and the design of the slurry wall,
this alternative should not affect future site work. This alternative,
however, may limit future development to some extent.
Groundwater Discharge Options
Alternatives 3 and 4 involve groundwater extraction. It is necessary to
provide for a discharge option for the extracted groundwater for both of
these alternatives. Three possible discharge options were developed.
The discharge options are as follows:
- Direct discharge to Coon Creek;
- Onsite treatment of groundwater with discharge to
Coon Creek; and
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- Discharge to the Metropolitan Waste Control Commission
(MWCC) publically-owned treatment works (POTW).
the choice of groundwater discharge option will depend on preliminary
work performed during the remedial design (RD) process. Information -
needed to make the final decision would include actual flow rates from
the extraction wells, confirmation of the levels of acetone, methylene
chloride and bis (2-ethylhexyl) phthalate present in the surficial
aquifer, the National Pollution Discharge Elimination System (NPDES)
permit requirements and possible interactions with the remedial action at
the WDE site.
Direct discharge of the extracted groundwater to Coon Creek would require
an NPDES permit. The NPDES perm-it sets specific contaminant discharge
limits for the discharged waters. The discharge limits would be
established by the State of Minnesota and would take into consideration
the size and flow rate of Coon Creek, contaminant levels in Coon Creek
from other sources and the uses of Coon Creek.
The levels of contaminants found in the surficial aquifer onsite
currently exceed two of the proposed discharge limitations to Coon Creek
provided by the MPCA. These compounds are toluene and bis (2-ethylhexyl)
phthalate. The toluene level only exceeds the proposed discharge
limitations in one monitoring well. The actual discharge level of
toluene, when the discharge of all the extraction wells are combined, is
expected to be below the discharge limitations. In this case, no
treatment prior to discharging may be needed. The level of bis (2-ethyl-
hexyl) phthalate significantly exceeds the proposed limitations, but has
not been confirmed and may be a laboratory or sampling contaminant. The
presence of this compound will be checked prior to determining the
discharge option. The cost of the direct discharge is $160,000. A
detailed breakdown of the cost is shown in Table 3.
If the NPDES discharge limits are exceeded by the extracted groundwater,
onsite treatment of groundwater prior to discharging to Coon Creek would
be provided as needed to meet proposed NPDES discharge limits established
by the MPCA.' A possible system was analyzed in the FS which would remove
inorganic, volatile organic and base/neutral organic contamination
through the use of an inorganic metal precipitator, an anthracite-
greensand filter, an air stripper, and a granulated activated carbon
system. This system is anticipated to meet a "best available technology
economically achievable" criteria for the treatment of groundwater.
Additional sample results during the remedial design may indicate parts
of the system are unnecessary. This option would require significant
operation and maintenance. Therefore, the maximum present worth cost of
an onsite treatment system is $1,700,000. A detailed breakdown of the
cost is shown in Table 3.
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TABLE 3
COST SUMMARY
ASSEMBLED
ALTERNATIVE
CAPITAL
COST
REPLACEMENT
COST
OPERATION
& MAINT.
PRESENT
WORTH
Alternative 1
NO ACTION
Alternative 2
ALTERNATIVE
WATER
SUPPLY
Alternative 3
. GROUNDWATER
EXTRACTION
Alternative 4
LATERAL
CONTAINMENT
$0
$65,000
$290,000
$0
$0
$0
$0. $48,000 $520,000
$50,100 $48,000 $760,000
$3,000,000 $50,100 $48,000 . $3,500,000
DISCHARGE
OPTIONS
CAPITAL
COST
REPLACEMENT
COST
OPERATION
& MAINT.
PRESENT
WORTH
DISCHARGE TO
COON CREEK
ON-SITE
TREATMENT -
DISCHARGE TO
COON CREEK
DISCHARGE
TO POTW
$160,000
$430,000
$26,000
$0
$0
$0 $160,000
$32,000 $140,000 $1,700,000
$31,000 $320,000
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The discharge to a POTVI option would entail sending the extracted
groundwater to the MWCC wastewater treatment system. The onsite sanitary
sewer lines could be used for this purpose. The MWCC POTW has adequate
capacity and is in compliance with all of its discharge permits. The
highest level for each of contaminants found in the surficial aquifer
onsite meet the pretreatment limits for the POTW with the exception of
acetone and 'zinc. The levels of acetone and zinc that will be present in
the combined discharge of the extraction wells are expected to meet the
pretreatment standards. The addition of the discharge stream is expected
to have little if any effect on the MWCC treatment system due to the low
contaminant levels and flow rates. The present worth cost for this
option is $320,000. A detailed breakdown of the cost is presented in
Table 3.
SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
The four alternatives assembled were evaluated based on the following
nine criteria :
- Overall protection of human health and the environment;
- Compliance with all federal and state applicable or
relevant and appropriate requirements (ARARs);
Reduction of toxicity, mobility or volume; .
- Short term effectiveness;
- Long term effectiveness;
Implementabil ity;
- Cost;
- Community acceptance; and
State acceptance.
A summary of the relative performance of the alternatives with respect to
each of the nine criteria is provided in this section.
Alternatives 2, 3 and 4 would all be effective in protecting public
health from ingestion and inhalation of the contaminants detected in the
upper aquifer and possibly present in the lower aquifer. By providing
municipal water to homes in the vicinity of the site, potential exposure
to contaminated groundwater is eliminated. Additionally, Alternatives 3
and 4 provide a level of current and future protection to the environment
by limiting contaminant migration offsite or into the lower aquifer
through extraction of contaminated groundwater from the surficial
aquifer. Alternative 2 does not provide protection to environmental
receptors. Alternative 1 does not provide protection to human health or
the environment.
Compliance with ARARs dealing with cleanup levels are not necessary for
operable units. However, while the operable unit does not have to meet
these ARARs, the final remedy will. Therefore, it is desirable that
this remedy meet all ARARs.
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The primary ARARs for this initial groundwater operable unit are the
maximum concentration limits (MCLs) under the Safe Drinking Water Act
(SDWA). MCLs are applicable where the water will be provided directly to
25 or more people or will be supplied to 15 or more service connections.
MCLs are relevant and appropriate where surface water or groundwater is
or may otherwise be used for drinking water. Alternatives 1 and 2 do not
address the contaminated groundwater and, therefore, do not meet the SDWA
ARARs. No reasonable grounds exist at the present time to justify a
waiver of this requirement at the present time for Alternatives 1 and 2.
Alternatives 3 and 4 meet the SDWA's MCLs by removing the contaminated
groundwater in the surficial aquifer which has been found to exceed the
MCLs. Also considered ARARs for the groundwater operable unit are the
RCRA groundwater protection standards. These use background, MCLs or
alternate concentration limits (ACLs) as the cleanup level. The criteria
for choosing between background, MCLs and ACLs are detailed In 40 CFR
Part 264.94,
Because the operable unit is being implemented for the purpose of
controlling contaminant migration as opposed to restoring the surficial
aquifer, the extraction well system will operate until the completion of
the subsequent RI/FS regardless of future contaminant levels. Final
cleanup levels will be established as a part of the subsequent RI/FS.
Additional ARARs, which are related to discharge options, would need to
be met if either Alternatives 3 or 4 were chosen. These include the
Clean Water Act, which covers discharges to surface water bodies, the
Clean Air Act, which covers air emissions and POTW pretreatment
requirements, which cover contaminant levels being discharged to a POTW.
The relevant ARARs will be met by the discharge option chosen.
The criterion dealing with the reduction of toxicity, mobility or volume
of contaminants only considers reductions due to treatment. Alternatives
1 and 2 do not incorporate any treatment. These alternatives, therefore,
do not reduce toxicity, mobility or volume. Alternatives 3 and 4 would
involve treatment if either the discharge to POTW option or the onsite
treatment with discharge to Coon Creek option is chosen. Both of these
discharge options involve treatment which would significantly reduce
mobility and'volume. If direct discharge to Coon Creek is chosen,
neither Alternative 3 nor 4 would involve treatment.
Alternatives 2, 3 and 4 provide a high degree of effectiveness in the
short term in achieving prompt protection of human health with no
significant adverse effects resulting from the implementation of the
remedy. The hook-up to municipal water supplies would not require any
significant time delays and is very effective in protecting the public
from any potential risks due to consumption of contaminated groundwater.
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Alternatives 3 and 4 are protective of the environment in the short term.
The anticipated implementation timeframe may be somewhat longer for
Alternative 4 due to the time required to design and construct a slurry
wall. The no action alternative is not adequately protective of human
health or the environment.
Alternatives 2, 3 and 4 are effective in providing long term protection
of human health. The hook-up to municipal water eliminates the need to
use groundwater on or near the site, but does not address the
contamination present in the shallow aquifer or the threat to the lower
aquifer. Alternatives 3 and 4 provide a moderate level of long term
effectiveness with regard to protection of the environment by controlling
contaminant migration. Neither Alternative 3 or 4 eliminates the
downward flow gradient through the aquitard or removes contaminants
already present in the aquitard, but both decrease the volume of downward
flow from the surficial aquifer and the volume of contaminants present in
the upper aquifer that pose a threat to the lower aquifer. Long term
issues will be addressed more fully in the a subsequent RI/FS. The no
action alternative is not adequately protective of human health and the
environment.
The implementability of each alternative is based on the technical
feasibility, administrative feasibility and the availability of services
and materials for the alternative. All of the alternatives are
technically-feasible. They all involve technologies which have been used
regularly in the past and have a demonstrated performance record. All of
the alternatives are administratively feasible. Alternatives 3 and 4
would require obtaining a NPDES permit if a surface water discharge is
used. Approval of the MWCC would be necessary if the POTW discharge is
chosen for Alternative 3 or 4. Alternative 4 may require additional
steps and time delays during design and in obtaining access and clearing
junk automobiles from around the site prior to the construction of a
slurry wall. The services and materials required for each alternative
are expected to be readily available.
There are no costs associated with Alternative 1, the no action
alternative. Alternative 2 has a total present worth cost of $520,000.
Alternative 3 has a total present worth cost of $760,000. Alternative 4
has a total present worth cost of $3,500,000. Alternatives 3 and 4 would
have the additional costs associated with the chosen discharge option. A
summary of the costs for each alternative is provided in Table 3.
Alternative 4 is not felt to offer significant increases in
protectiveness to public health and the environment, short term
effectiveness or long term effectiveness for the extra cost.
Limited comments were received from the community regarding the various
alternatives considered. The comments received indicated the communities
concern regarding the discharge options which were considered in the
event a groundwater extraction alternative was chosen. These comments
indicated a general opposition from the community, including
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representatives from Anoka County, to a discharge to Coon Creek.
Representatives from the City of Andover expressed concern regarding any
discharge to the City's sewer system due to the volume limits set by the
HWCC for the City and the resulting displacement of potential future
development.
The State of Minnesota, through the MPCA, has been actively involved in
the RI/FS process for the South Andover site. The MPCA concurs with
the U.S. EPA's selected alternative. The selected alternative must be
presented to Minnesota's Citizen Review Board prior to the State's
commitment to fund 10 percent of the remedial action.
SELECTED ALTERNATIVE
Based on available data and analysis conducted to date, the U.S. EPA
selects Alternative 3 as the most appropriate solution for meeting the
goals of the initial groundwater operable unit at the South Andover site.
The characteristics of Alternative 3 that are considered most important
are:
- The alternative provides immediate protection to human health
from the potential threats associated with consumption of.
groundwater from the site.
- The alternative limits migration of groundwater offsite and
controls migration of contaminants into the aquitard and lower
aquifers.
- The alternative provides for management of surface water
quality through monitoring of contaminant levels in the
surficial aquifer and possible surface water discharges.
- The alternative is consistent with additional site actions and
will be compatible with the final site remedy.
Clean-up Levels
The initial groundwater operable unit is being implemented for the
purpose of controlling contaminant migration not restoration of the
surficial aquifer to drinking water standards. Therefore, no cleanup
levels are being established at this time. The extraction system will
operate until the completion of the subsequent RI/FS. At that time, the
groundwater operable unit will be incorporated into the overall site
remedy and clean-up levels will be set. The levels to be set are
expected to meet all Federal and State ARARs.
Due to the discontinuous and possibly intermittent nature of the
contamination, continuous extraction of the groundwater would provide a
more reliable migration control system than one which would pump only
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when analytical data indicates a contaminant specific or risk specific
action level was exceeded. The continuous extraction is also supported
by the predominately downward gradient which exists through the aquitard.
By increasing the horizontal gradient through the remainder of the study,
the chances of capturing contaminants, prior to them entering the
aquitard, is increased.
A second important advantage of continuous extraction is that extraction
could significantly aid the subsequent RI in locating potential sources
of contamination. Previous efforts, using monitor wells and soil gas
analysis, did not locate any source areas of high concentration in
groundwater or soil. The gradients caused by the extraction wells will
potentially draw in pockets of high contamination and facilitate the
pinpointing of the source areas.
Operation and Maintenance
The recommended alternative requires a certain degree of annual operation
and maintenance (O&M) activity to ensure that groundwater will be
extracted and treated to meet the clean-up levels. The degree of O&M
cannot be determined until the discharge option is selected. Direct
discharge to Coon Creek and discharge to the POTW would both .require
monitoring of the discharge contaminant levels. An O&M plan will need to
be developed during remedial design after the groundwater discharge
option has been chosen.
A groundwater monitoring plan will also need to be developed and
implemented to determine if contaminants have migrated offsite or into
the lower aquifer. This can be incorporated into the subsequent RI/FS
work planned for the site.
All O&M responsibilities will be covered as specified in Section 104(c)
of SARA. The O&M plan will be reviewed at the completion of the
subsequent RI/FS and be incorporated into the final remedy.
STATUTORY DETERMINATIONS
The U.S. EPA and MPCA believe that this remedy will satisfy the statutory
requirements of providing protection of human health and the environment,
attaining applicable or relevant and appropriate requirements of other
environmental statutes, will be cost-effective, and will utilize
permanent solutions and alternative treatment technologies or resource
recovery technologies to the maximum extent practicable. The choice of
discharge option for the extracted groundwater will determine whether
this operable unit will satisfy the preference for treatment as a
principal element.
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Protectlon of Human Health and the Environment
The selected remedy provides adequate protection of human health and the
environment by preventing consumption of contaminated groundwater through
the provision of an alternate water supply, limiting offsite migration1 if
contaminated groundwater and protecting the deeper aquifer from becoming
contaminated by the implementation of a groundwater extraction system.
Additional controls on exposure are achieved through restrictions on new
wells on or near the site and through monitoring of groundwater at the
site.
Attainment of Applicable or Relevant and Appropriate Requirements
This remedy will ensure that drinking water to be supplied to current
private well users will attain MCLs under the SDWA and that the discharge
from the groundwater extraction system will meet NPDES limitations under
the Clean Water Act if discharged to Coon Creek.
Cost-Effectiveness
This alternative affords a high degree of overall effectiveness in not
only protecting existing well users against exposure to contaminated
groundwater through the provision of an alternate water supply, but also
in halting further migration of the contaminated groundwater offsite and
into the lower drinking water aquifer through the extraction system. The
present worth cost of this action will range from $920,000 to $2,460,000
depending on the discharge option selected during design. This compares
with the $3,500,000 required to construct a slurry wall around the site.
U.S. EPA believes the costs of the selected remedy are proportionate to
the overall effectiveness it affords such that it represents a reasonable
value for the money.
Utilization of Permanent Solutions and Alternative Treatment Technologies
or Resource Recovery Technologies to the Maximum Extent Practicable
U.S. EPA believes this remedy is the most appropriate solution for
meeting the goals of the initial groundwater operable unit at the South
Andover site providing the best balance among the evaluation criteria for
the alternatives evaluated. This remedy provides effective protection in
both the short- and long-term to potential human and environmental
receptors, protects the deeper aquifer from becoming contaminated, is
readily implemented, is cost effective and is consistent with future
response actions that may be undertaken at the site.
Preference for Treatment as a Principal Element
Due to the limited scope of this remedy, which 1s not the final response
action for any of the principal threats posed by the site, the statutory
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preference for treatment may not be met. The choice of discharge option
during design will determine if the preference is achieved. Subsequent
actions are planned, however, that will definitively address the
principal threats.
SCHEDULE
The remedial action start is one of the 175 sites comprising a statutory
goal for remedial a.ction starts by October 1989. The following are the
key milestones for implementation of the remedial action in the event
that RD/RA negotiations are not successful.
Approve Remedial Action (execute ROD) March 1988
Initiate Remedial Design June 1988
Complete Remedial Design June 1989
Initiate Remedial Action (Award Contract) September 1989
FUTURE ACTION
A detailed study of a large portion of the site was impossible due to the
large volume of tires and junk automobiles present onsite. The tires are
currently being shredded onsite and sent offsite. The operation is
taking place under a grant from the Minnesota Waste Management Board and
is scheduled to be completed by Spring 1989.
A subsequent RI/FS is planned for the site following the tire removal.
The subsequent RI/FS will study and determine appropriate final
groundwater remediation and source control measures.
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