Environmental Protection
Agency
Emergency end
Remedial Response
June 1984
Superfund
Record of
          RODR0584008
Reilly Tar Site, MN

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                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing/
1. REPORT NO.
   EPA/ROD/R05-84/008
             3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
   SUPERFUND RECORD OF DECISION:
   Reilly Tar Site, MN
             5. REPORT DATE
              06/06/84
             6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
                                                            8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
                                                            10. PROGRAM ELEMENT NO.
                                                            11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
  U.S.  Environmental Protection Agency
  401 M Street,  S.W.
  Washington,  D.C.    20460
             13. TYPE OF REPORT AND PERIOD COVERED
             	Final  ROD Rpno-rt-	
             14. SPONSORING AGENCY CODE

                 800/00
15. SUPPLEMENTARY NOTES
16. ABSTRACT
       The  Reilly Tar and Chemical Site occupies 80  acres in St. Louis Park,
  Minnesota.   The Republic Creosote Works, which operated at the site between 1917
  and 1972,  fractionalized coal  tar into various oils  and produced creosote.   The
  wastes  resulting from this process polluted the land surface of the site  and four
  underlying aquifers.  The pollutants consisted primarily of polynuclear aromatic
  hydrocarbons (PAH)  and related coal tar derivatives.
       The  cost-effective remedial alternative selected for this site is treatment
  of the  St.  Louis Park Well SLP-15/10 by a granular activated carbon  (GAC) water
  treatment system.  GAC provides best available technology to restore drinking water
  quality and will also help prevent the pread of contamination.  The estimated total
  capital cost is $750,000 and the first year O&M cost is estimated at $188,000.

  Key Words:   Ambient Water Quality  Criteria,  Benzo(a)  Pyrene,  Drinking Water Supplies,
               PAH,  Risk Level, Operational Target,  Ground Water,  Ground Water Treatment,
               RCRA Part 264,  Best Available Technology, Carbon  Adsorption
 7.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
                                              b.lDENTIFIERS/OPEN ENDED TERMS  C.  COSATI Field/Group
  Record of  Decision
  Reilly Tar Site,  MN
  Contaminated media:  gw,  sw, soil,_peat bog
  Key contaminants:  PAHs, coal tar wastes,
   oils, grease,  phenolics,  creosote
18. DISTRIBUTION STATEMENT
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        None
21. NO. OF PAGES
      72
                                               20. SECURITY CLASS (Thispage)
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                                                                          22. PRICE
EPA Form 2220.1 (R«v. 4-77)   PREVIOUS EDITION is OBSOLETE

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EPA Form 2220-1  (R«v. 4-77) (R«ver»e)

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                          ROD ISSUES ABSTRACT
Site;    Reilly Tar, Minnesota

Region;  V

AA, OSWER
Briefing Date;  May 25, 1984
                            SITE  DESCRIPTION

    The Reilly Tar and Chemical Site occupies 80 acres in St. Louis
Park, Minnesota.  The Republic Creosote Works, which operated at the
site between 1917 and 1972, fractionalized coal tar into various oils
and produced creosote.  The wastes resulting from this-process polluted
the land surface of the site and four underlying aquifers.  The pollu-
tants consisted primarily of polynuclear aromatic nydrocarbons  (PAH)
and related coal tar derivatives.

                          SELECTED ALTERNATIVE

    The cost-effective remedial alternative selected for this site is
treatment of the St. Louis Park Well SLP-15/10 by a granular activated
carbon (GAC) water treatment system.  GAC provides best available tec^-
nology to restore drinking water quality and will also help prevent
spread of contamination.  The estimated total capital cost is $750,Oi,, .
and the first year O&M cost is estimated at $188,000.


             ISSUES AND RESOLUTIONS                KEY WORDS

1.  Using the "Ambient Water Quality Criteria for  .  Ambient Water
    Polynuclear Aromatic Hydrocarbons (PAH)," pub-    Quality Criteria
    lished by EPA, a target health risk of 10"°    .  Benzo(a) Pyrene
    was recommended for the sum of carcin-         .  Drinking Water
    ogenic PAH.  The 10~° level for Benzo(a)           Supplies
    Pyrene  (BaP), 2.8 ng/1, was used as a target   .  Polynuclear
    for all carcinogenic PAH since BaP is con-        Aromatic
    sidered to be the most potent carcinogen of       Hydrocarbons
    the PAH family.  Using 2.8 ng/1 for the 10"6       (PAH)
    target for all carcinogenic PAH is a conser-   .  Risk Level
    vative approach and is justified due to the
    relationship of other PAH to the activation
    of carcinogenic PAH, the inability of the
    analytical method to distinguish between
    certain carcinogens and other PAH, and the
    possioility that other PAH may still be toxic,
    tumor promoters and/or mutagens.
                                  -1-

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Reilly Tar, Minnesota
May 25, 1984
Continued
             ISSUES AND RESOLUTIONS

    An operational target of 280 ng/1 total PAH
    was selected due to the difficulty in moni-
    toring for the low levels of carcinogenic
    PAH.  The operational target is based on a
    ratio of carcinogens to total PAH calculated
    using site data.  The operational target
    will be used to monitor operations of the
    treatment system and will be adjusted
    periodically.

    The target health risk of 10"6 was
    selected based on a range of risk levels
    resulting from treating contaminated ground
    water for direct public consumption.  The
    level was not selected to satisfy the
    ground water protection requirements of
    RCRA Part 264.  The next operable unit
    for this site will address off-site
    remedial measures to control contaminated
    ground water plumes in the four aquifers
    beneath the site.  The next operable unit
    will also consider the requirements for
    restoring ground water under Part 264 of
    RCRA.

    EPA has selected granular activated carbon
    (GAG) as the recommended alternative capable
    of achieving the target for carcinogenic PAH
    (based on BaP) of 2.8 ng/1 which corresponds
    to a 10"6 health risk factor.  Use of GAC
    has proven to be reliable and is considered
    to be effective for water supply treatment
    since it can be operated over a wide range to
    remove carcinogenic and other compounds to
    below detection limits, it can accept slug
    loads, it can be maintained with minimal
    operator oversight, and there is no
    generation of by-products in the effluent
    stream.
KEY WORDS

.  Operational
  Target
.  PAH
   Ground Water
   Ground Water
   Treatment
   RCRA Part 264
   Risk Level
    Best Available
    Technology
    Carbon
    Adsorption
                                  -2-

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                             Record of Decision

                   Remedial Action Alternative Selection
Site;  Reilly Tar Site in St. Louis Park, Minnesota.


Documents Reviewed

     I have reviewed the following documents describing the analysis  of
cost-effectiveness of remedial alternatives for the Reilly Tar site in
St. Louis Park, Minnesota.

          "Evaluation of Ground Water Treatment and Water Supply Alternatives
          for St. Louis Park, Minnesota," O^M-Hill,  June 1983.

          Summary of Remedial Alternative Selection.

          "Study of Ground Water Contamination in St.  Louis Park,  Mn.,"
          E. A. Hickock and Associates,  November 1981.

          "Transport of Coal Tar Derivatives in the Prairie du Chien-Jordan
          Aquifer," USGS, February 1931.

          "Recommended Plan for a Comprehensive Solution of the Polynu-
          clear Aromatic Hydrocarbon Problem in the St.  Louis  Park Area,"
          Environmental Research and Technology, Incorporated,  April
          1983, Performed for and at the expense of Reilly Tar and Cherrdcal
          Corporation.

Description of Selected Remedy

          Construction of a granular activated carbon (GAC) water  treat-
          ment system at St. Louis Park  Well 15/10 as a  major  component
          of restoration of drinking water quality to St.  Louis Park,
          Minnesota.

          Operation of the above system  at 1200 gallons  per minute will
          also serve as a major component of a gradient  control well
          system.  The operation of the  gradient control well  system
          will protect the drinking water supplies of neighboring  cities
          from contamination, and allow  St.  Louis Park eventually  to
          open other wells closed due to contamination.

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                                   -  2 -


 Declarations

     Consistent with the Comprehensive Environmental Response, Compensation
 and  Liability Act of 1980  (CERCLA) and the National Contingency Plan  (40
 CFR  Part  300), I have determined that installation of a granular activated .
 carbon water treatment system at St.  Louis Park well 15/10  is a cost-
 effective remedy and provides adequate protection of public health, welfare,
 and  the environment.  The  Minnesota Pollution Control Agency has been
 consulted and agrees with  the approved remedy.  In addition, this action
 will require future operation and maintenance to ensure the continued
 effectiveness of the remedy.  These activities will be considered as part
 of the approved action and eligible for  Trust Fund monies for a period of
 up to one year.

     I have also determined that the  action being taken is  appropriate
 when balanced against the  availability of Trust Fund monies for use at
 other sites, and is consistent with a permanent remedy at the site.

     I am approving the installation  of  a granular activated carbon treat-
ment system since a delay  would create an unnecessary risk  to the public
health during peak usage of the City's water supply and allow the contam-
 ination to migrate further towards other municipal water supplies.

     The  State has largely completed  a feasibility study for remedying the
remaining problems at the  site.  The  extent of ground water contamination
has been determined for some additional  aquifers affected by the Reilly Tar
operation.

     Following completion  of the feasibility study, the State will conduct
 a public meeting on any additional remedies required to mitigate the con-
 taminated ground water plume and source  of contamination at the site.
After submittal of their recommendation, I will make a further determi-
nation on the appropriate  remedy for  the remaining stjdy areas.
Date /   .1                                      Lee1 M. Thomas
                                                Assistant Administrator

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                                                                   May 25, 1934


                               RECORD OF DECISION

                             REILLY TAR, MINNESOTA


                               EXECUTIVE SUMMARY


PURPOSE

     The purpose of this Record of Decision (ROD) is to select an appropriate
remedial action at the Reilly Tar site, St. Louis Park, Minnesota that is
consistent with the requirements of CERCLA and the NCP.  The Assistant Admin-
istrator has been delegated the authority for that approval.

     The primary source of drinking water for 3 cities, St. Louis Park, Edina,
and Hopkins, which border Minneapolis has been contaminated by coal tar com-
pounds produced by Reilly Tar.  Since 1978, a total of 6 wells were closed and
water conservation measures and contingency plans for purchase of alternate
water supplies have been implemented by St. Louis Park.  During fire emergencies,
contaminated wells must be turned on.  A total of 33% of the pre-1978 water
supply capacity has been usurped by contamination.  Public opinion is in favor
of restoring adequately treated water to the distribution system as soon as
possible.  The State share of this project is 10%.  Concurrence by all Federal
and State authorities has been obtained.  Unfortunately, the City of St. Louis
Park will have to continue water conservation measures this summer since
operation of the system will start 8 months after approval.  The public would
support construction beginning this summer.

BACKGROUND

     The Reilly Tar and Chemical site occupied 80 acres in St. Louis Park,
Minnesota.  It was called Republic Creosote Vtorks and operated between 1917
and 1972.  The Company fractionalized coal tar into various oils and produced
creosote.  The creosote and waste products resulting from the Company's process
polluted the surface of the site and 4 aquifers.  The deep aquifers were polluted
by direct migration of contaminants with the aquifers via a deep well located
on-site.  The contaminants were either injected into the well or overflowed
into the well casing during runoff events and spills on the site.  Consequently,
many private wells and eventually municipal supplies became contaminated.
Limited studies on portions of the site started in 1969.  Ground water studies
began in 1974 and drinking water treatability testing was initiated by a
cooperative agreement between MPCA and EPA in 1981.  The work performed under
this cooperative agreement, funded at $400,000, included:  (1) a well survey
to determine the amount of multi-aquifer wells that were conveying contamination
between aquifers; (2) a cleanout of one on-site well known to contain coal tar
contamination; and (3) a feasibility study for water treatment at St. Louis
Park.  A second cooperative agreement was awarded in December 1982 for $1.9
million.  This agreement was to accomplish the following:  (1) an initial
remedial measure to abandon multi-aquifer wells; (2) model gradient control
well systems; (3) a remedial investigation to determine areal extent of
contamination of the source material; and (4) a feasibility study for source

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                                     - 2 -
  \.

control measures.  The initial remedial measure was delayed while Reilly completed
and presented the findings of their own feasibility study.  Now that negotiations
with Reilly have terminated the activities funded by the second cooperative
agreement will be completed during 1984.

     The feasibility study funded by the first cooperative agreement reccrnmended
restoration of drinking water quality to the contaminated aquifer by installing
granular activated carbon (GAC) treatment at an existing contaminated well.
That action is the subject of this Record of Decision.  This alternative
provides a multi-purpose project and multiple benefits.  It not only provides
a cost-effective alternative when compared to other alternatives for restoring
drinking water quality but, it also helps block the spread of contamination
which would otherwise force the closure of more municipal wells.

     The attached chart lists the alternatives, costs, advantages, and dis-
advantages to restore safe drinking water quality and quantity to the City of
St. Louis Park.  Alternative 2, 3, and 4 restore drinking water to St. Louis
Park.  Alternative 4; however, considers various levels of treatment of the
contaminated aquifer to provide water quality to St. Louis Park.  Alternatives
2, and 3 provide water from uncontaminated sources.  Alternative 4, by provid-
ing water from the contaminated aquifer also assists in retracting the plume
and allows the opening of 2 other closed wells.  Therefore, any additional cost
to retract the plume will be minimized.  The capital cost of the GAC treatment
system is 5633,000.  Restoration of the existing well where the treatment
system will be constructed is estimated to cost $49,000.  Design is estimated
at 368,000.  Therefore the total project cost is estimated at $750,000.  The
first year O&M cost is estimated at $188,000.

     The public, through the efforts of St. Louis Park and MPCA, have been
well informed of the drinking water problems since 1978.  Thus, at the public
meeting where the MPCA presented the proposed GAC alternative, the primary
concerns of the citizens was the urgency of restoring the drinking water on
a timely basis.  Another main concern regarded the payment of the system.  The
citizens were told that the proposal would be submitted to EPA for a funding
decision and that costs would be recovered, by legal means, from the Reilly
Tar and Chemical Corporation.  The City keeps the public informed of the drink-
ing water problem on a monthly basis through committee meetings specifically
established for this problem.

     The State and Region recommend implementation of GAC treatment to a level
that represents 10~^ health risk or less.  This alternative accomplishes The
objective of restoring water quality and quantity to St. Louis Park.  All
other alternatives provide adequate water quality but do not block the spread
of the contaminated plume and allows the opening of previously closed wells.

FURTHER NEEDS FOR SITE CLEANUP

     There are 3 other aquifers contaminated with PAH wastes from Reilly Tar.
These aquifers may need remedial action in order to protect future uses of the
uncontaminated portions of the aquifers.  This may require pump-out wells to
limit the spread of contamination and protect down-gradient use of the aquifer.
These aquifers currently have limited use in the areas of contamination and

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                                     - 3 -
 *

pose no immediate endangerment to municipalities' drinking water.  In addition,
creosote waste has accumulated in surface areas and acts as a continuing source
of ground water contamination.  The State is completing feasibility studies fc
both source control measures and additional ground water control measures.   AT
additional Record of Decision will be prepared to request approval of these
additional measures.  The attached schedule shows the sequence and duration of
site activities.

ENFORCEMENT STATUS

     EPA and U.S. DQJ is aggressively proceeding with litigation against the
Reilly Tar and Chemical Company.  Protracted discussions with Reilly Tar have
not produced a concurrence by Reilly with the stated objectives of the EPA and
MPCA.

NEXT STEPS

     Milestones                                           Date

     Sign Record of Decision                              May 1984
     Amend CA for Design and Construction                 June 1984
     Complete Design                                      August 1984
     Complete Construction                                June 1985

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                                                              TAR, MN
Al ternat i ve
Cost ($1
Capital
,000)
Present
Worth
Public Health
Cc >ns i de ra t i ons
Rrv
Coi
                                                          Rnvi ronmental
                                                          Considerations
                                                               Technical
                                                               Cons iderat ions
                                                             Public
                                                             Garment
1. No Action.
2. Hookup to
   Minneapolis.
  $250   $8,102
3. Drill Deeper
   Wells.
$1,870   $2,916
4. Aquifer Treatment.
   A. Ozone
  $374   $1,618
                   $459   $2,109
                   $709   $2,434
                  Unacceptable exposure  Continued migration
to PAH  if summer or
tire demand  requires
use of contaminated
well.  Continued
water shortages.

Reduces public health
threat to less than
10~6.
Reduces public health
threat to less than
10~6.
At 2000 ng/1 of PAH,
removes taste and
odor, but results in
Ifr5 to 10 ~6 risk.

At 1000 ny/1 of PAH,
results in 10"5 to
]0~f) risk.
                  At 280 ncj/1 of PAH,
                  results in 10~6
                  less risk.
                                                   or
                                                          of contaminated
                                                          ground water;  leading
                                                          to contamination of
                                                          Kdina's water  supply.
Continued migration   Relies on
of. contaminated       simple
ground water; leading technology.
to contamination of    No treatment
Fdina's water supply,  is required.
Continued migration
of contaminated
ground water leading
to con tami nation of
Fd i na's wa ter supply.
Depletes limited
water resource
in deeper aquifer.
Hlocks migration and
allows additional
wells to be queried.
Relies on
proven
construction
technology.
                                      High
                                      resistance.
                Acceptable.
Acceptable.
to St. Louis
Park, but
not to Kdina
or Hopkins.
Not used on
wide scale.
Less respon-
sive to slug
loading than
GAC.  Would be
expensive to
retrofit if
treatment goals
change.  Certa i n-
ty that target
risk levels
will be con-
sistently
met is low due
to operational
inflexibility.
Acceptable.
                                                    (ther
              Has signif iean
              ly higher O4.M
              and present
              worth cost.
Has second
highest presen
worth cost.
Present wort h
Present worth
is less thf>
GAC at hig
risk level,
but more at
lower treat-
ment goals
change.

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                                                 RKILLY TAR, MN  (Continued)
Alternative
             Cost ($1,000)
                      Present  Pub]ic Health
             Capital  Worth    Considera t i ons
Environmental
Cons idera t i ons
4. B. Granular
   Act i vated
   Carbon (GAC)
               $633   $2,150   At 2000 ncj/1 of PAH,
                               removes taste and
                               odor but results in
                               1CT5 to 10~6 risk.

               $633   $2,263   At 1000 ng/1 of PAH,
                               results in 10~^ to
                               10~6 risk.

               $633   $2,405*  At 280 ng/1 of PAH,
                               results in 10~6 or
                               less risk.**
Blocks migration and
allows additional
wells to be opened.
Technical
Cons i de ra t i ons
Public
Comment
Other
Considered
best avail-
able tech-
nology.
Dependable
over a wide
range of
operating
conditions.
Responds
well to slug
loading
Likely to
consistently
meet risk
target.
Acceptable.
Present worth
is less than
other tech-
nologies a
recatmended
treatment
level.
**
Recommended Alternative

280 ng/1 is the operational performance target for the f;AC treatment system at this site.
  The carcinogenic PAH will be reduced to a level less than or equal to 2.8 ng/1 as a
  result of the operational performance target.  This will assure that the health risk
  to the population is less than or equal to a 10"^ health risk.

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1) MULTIPLE AQUIFER GRADIENT
   CONTROL DISCHARGE

2) SOURCE CONTROL

3) SOIL BORINGS SOUTH
   OK REILLY SITE

4) RD/RA FOR DRINKING WATER
   AT SLP 15/10

5) 1RM ON MULTI-AQUIFER WELL
   CUOSURE

6) NEGOTIATION WITH RE ILLY
   ON TASKS 1, 2, 3, & 5,
   A.O. FOR TASK 4
           REILLY TAR
 SCHEDULE OK REMEDIAL ACTIVITIES

	1984	1985	'__
 JASON   D      JFMAMvJJASOND

              FS                  Public
 <	>      Comment           RD/RA
                                <	1	>
                FS
 <	>




 ^—•——•  —  — — —, — — — — — __-. — _ _^__^.__ — _—____•.___«.__„___—__._^


                                    <	>


 <	>

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                 Summary of Remedial Alternative Selection

                      Reilly Tar and Qiemical Conpany

                         St. Louis Park, Minnesota
SITE LOCATION AND DESCRIPTION

     The Reilly Tar and Chemical Conpany site occupied 80 acres of land
located in St. Louis Park, Minnesota.  A copy of a site map is attached
(Figure 1).  The plant site, called the Republic Creosote Works, was located
west of Gorham, Republic and Louisiana Avenues, south of 32nd Street, east
of Pennsylvania Avenue, and north of Walker Street.  The conpany no longer
owns the land; the City of St. Louis Park purchased the land from Reilly in
1972 and it is currently owned by the St. Louis Park Housing and Redevelop-
ment Authority.  The City is contiguous to the City of Minneapolis and
exhibits a similar population density.  Currently, the site is a park with
a portion of it developed with condominiums.  It is located in the midst
of a residential area with some small industry.
SITE HISTORY

     From 1918 to 1972 the company operated a coal tar distillation facility
and wood preserving plant.  Its primary production was creosote.  The
chemical compounds associated with this process are polynuclear aromatic
hydrocarbons (PAH) and phenolics.  Many of these compounds pose health
risks and some are carcinogenic.  The release to the environment of these
compounds occurred during the coal distillation process and from materials
stored on the site.  The materials were apparently dumped into a well,
referred to as W-23, which penetrated to the Mt. SiJion/Hinckley Aquifer,
a depth of about 900 feet.  The well was cleaned out by the Minnesota
Pollution Control Agency (MPCA) to a depth of 866 feet.  Coal tar was
removed down to a depth of 740 feet.  Evidence of contamination of the Mt.
Simon/Hinckley Aquifer has not been found at this time.  Wastes containing
coal tar and its distillation by-products were discharged, as a matter of
disposal practice, overland into ditches that emptied into a peat bog
south of the site.  This practice, according to Reilly, occurred from 1917
to 1939.  Figures 3a and 3b display, respectively, photos taken in 1947 -
when the wood treating process was very active and in 1980 - after the
City of St. Louis Park had landscaped the property and allowed some con-
struction on the site.  In 1940 and 1941 Reilly installed a wastewater
treatment plant and discharged the effluent into the bog south of the site.
The values of both phenolics and oil and grease in the discharge water
varied typically from 100 to 1000 milligrams per liter.  This discharge
continued for the duration of Reilly's operation.  The peat bog has retain-
ed contamination that was discharged over the years and, as is explained
below, is now a major source of ground water contamination.

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      FIGURE  1
STUDY AREA LOCATION

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(M




o
M
Cn
. *-    -Xi-     v\> uv,-
ti'"   '^srr*  " *W*  -
Counu/Club    •,  /  0\lf |(^
                                                    OCAT

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FIGURE 3(a!

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FIGURE 3(b)

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                                   - 2 -
     In 1972 the plant was dismantled and the land sold to the City of
St.  Louis Park.  In  1973 a storm water runoff collection system was built
which fed into a lined pond on the site (Figure 3b).  The pond on the site
discharges into a drain which is routed to another pond off-site before it
eventually discharges into Minnehaha Creek.  The City of St. Louis Park
(SLP) monitors the discharge into the creek.  Construction of a block of
condominiums on the northern part of the site began in 1976.  At this
time, no further construction is underway, although plans for new develop-
ment of the site are pending by the Housing and Redevelopment Authority.
All excavation of material has been inspected by the State and if found
contaminated, the soils were disposed of.

     The City of St. Louis Park drilled its first municipal well, W112,
in 1932.  The well, drilled to the Prairie du Chien-Jordan Aquifer, was
closed within two weeks of its startup because of bad taste and odors.
Several private wells near the plant site also exhibited contamination
in water drawn from the Drift/Platteville Aquifer, during the 1930's and
1940's.  Municipal wells continued to be constructed into the Prairie du
Chien-Jordan Aquifer, further away from the Reilly site.

     In the later 1970's the MDH used a more sensitive method of PAH
analysis using High Performance Liquid Chromatography.  This method allows
detection limits to less than 10 parts per trillion (ppt) for each PAH
component resolved on the chronatogram.  As a result, St. Louis Park
Well 10 (SLP 10) and SLP 15, which are contiguous, were closed in November
1978 due to elevated levels of PAH in the untreated water.  SLP 7 and SLP
9 were also closed due to their proximity to the contaminated plume and
due to the concern that, with SLP 10 and 15 shut down, the hydraulic
gradient would be controlled by SLP 7 and 9 and thus, these wells would
quickly became more contaminated.  In December 1979, SLP 4 was also closed
due to elevated PAH.  SLP 5 was also closed due to elevated concentrations
of PAH.  In March 1981, a City of Hopkins Well, H3, was closed due to
elevated concentrations of PAH.  The amount of water supply lost to the
City of St.  Louis Park due to the closure of six wells is approximately
35% of the capacity existing prior to 1978, the year when wells were first
closed.  Consequently, the city instituted a water conservation program
during the summer, increased pumping rates at uncontaminated wells and
drilled a new well, SLP 17, to the deeper Mt. Simon-Hinekley aquifer.
These measures do not provide a full water supply to the city.  Even with
SLP 17 on-line, the City still falls substantially short of peak water
supply needs during the summer months.  This is due, in part, to the
limited yield of the Mt.  Simon-Hinekley aquifer with the results that
SLP 17 cannot be pumped at full capacity.

     The City also has an agreement to purchase a limited amount of water
from the neighboring City of Plymouth.  However, Plymouth experiences
water shortages and peak demands at the same time as the City of St. Louis
Park.  As a result, Plymouth cannot supply St. Louis Park on a consistent
or dependable basis.  This situation was highlighted last summer during a
fire when the City turned on contaminated wells to provide enough water
pressure in the distribution system.  This situation is expected to recur
in the future.  The City has made plans to notify its citizens prior to
returning contaminated wells to service for emergency situations.

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                                   - 3 -
Summary of Previous and Current Superfund Activities

     There are three conceptual operable units involved with the Reilly
Tar remedial response.  These include:  (1) restoration of drinking water
supply to St. Louis Park, (2) containment or treatment of ground water in
contaminated aquifers, and  (3) source control of the bog and contaminated
soil at the site.

     In August 1981 the MPCA was awarded a cooperative agreement to
investigate Well W23, and to perform a  feasibility study for restoration
of drinking water which serves as the basis for this Record of Decision.
During that study the State removed coal tar deposits from Well W23 that
were a source of ground water contamination.  The well itself is now clean
although some residual contamination probably remains in the aquifers
penetrated by the well.  In December 1982 a second $1.9 million cooperative
agreement was awarded to the MPCA to accomplish the following tasks:

     (1)  An Immediate Remedial Measure to abandon multi-aquifer wells
          such as Well W105 located on  site.  This partially fulfills
          operable unit (2) above,

     (2)  Model and test previously proposed gradient control well systems
          in Prairie du Chien/Jordan Aquifer.  This partially fulfills
          operable unit (2) above,

     (3)  Compile existing soil logs and analytical data to determine extent
          of contamination.  This partially fulfills operable unit (3) above,
          and

     (4)  A feasibility study for the source material to fulfill operable
          unit (3) above.

     Tasks number (2) and (3) are substantially complete.  Tasks number (1)
and (4) which constitute approximately  $1.4 million of the cooperative
agreement have been delayed while feasibility work accomplished by Reilly
Tar through its consultants was conducted over the last year.  Since the
Reilly work was performed concurrently  with implementation of the cooperative
agreement, the MPCA and EPA withheld some major expenditures in anticipation
of a useful work product produced by Reilly and possibly the implementation
of certain cooperative agreement tasks  by Reilly.  To date, Reilly has not
accepted the responsibility for implementation of the tasks under the
current agreement which will be somewhat modified in an amendment forth-
coming from the MPCA.  The amendment will reflect the input provided by
Reilly for solution of the total problems at the site.  Due to the Reilly
study, the MPCA will need only to perform a limited feasibility study for
disposition of gradient control well discharge and some remedial investi-
gation of soils off-site for the purpose of establishing deed restrictions
and of Drift/Platteville and St. Peter  Aquifers.  There exists enough money
in the current agreement to reprogram for design and construction of the
highest priority task, the drinking water treatment system proposed in this
Record of Decision.  The remedy described herein pertains only to funding
a water treatment system for St. Louis  Park Well SLP 15/10.  A second
Record of Decision addressing the remaining site problems is anticipated
for submittal following completion of the on-going feasibility activities.

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                                   - 4 -
 >

ENFORCEMENT HISTORY

     On September 4, 1980, the U.S. Department of Justice (USDQJ) filed a
complaint against Reilly Tar under Section 7003 of RCRA.  The State moved
to intervene as a plaintiff.

     On October 1980, an order was entered granting the Stat-e of Minnesota
and the City of St. Louis Park leave to intervene as co-plaintiffs in Federal
enforcement.

     On February 25, 1981, a demand letter was sent from the U.S. Attorney
to Reilly Tar.

     On March 27, 1981, Reilly denied liability for any remedial action
costs.

     On August 17, 1981, another demand letter was sent to Reilly Tar
requiring payment of $200,000 for remedial measures to be taken at the
site by the MPCA through a cooperative agreement with EPA.

     On September 25, 1981, a CERCLA Count was added to the complaint.

     On January 15, 1982, Judge Paul Magnuson heard arguments on the Motion
to Dismiss filed by Reilly Tar.

     On August 20,1982, Reilly's Motion to Dismiss was denied.

     On July 22, 1982, the USDQJ requested that Reilly submit a work plan
for remedying the pollution problem at the Reilly Tar site within 30 days.
Reilly did not submit a plan within that period.

     At a meeting held on August 24, 1982, Reilly proposed to prepare
a comprehensive plan' to remedy the PAH problem.  However, EPA and MPCA
indicated that they would  go ahead with the work planned under the
cooperative agreement pending receipt of Reilly's plan.

Summarv of Technical Discussions With Reillv
     In May 1982, following a series of letters and meetings among the DOJ,
EPA, MPCA, and Reilly Tar, Reilly proposed to perform its own comprehensive
plan to solve the PAH problems in the St. Louis Park area.  This was  initiated
in August 1982.  The MPCA continued work on the feasibility study for
water treatment under the cooperative agreement with EPA.

     In May 1983, Reilly publicly presented its plan to clean up the
contaminated site in St. Louis Park.  During the summer, MPCA and EPA
reviewed Reilly's plan.  From August through December 1983, MPCA and  EPA
technical representatives met with Reilly Tar technical consultants to
determine if the regulatory agencies and Reilly Tar had common  solutions
to the problems caused by Reilly's operation in St. Louis Park.

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                                   - 5 -
     Discussions ended with Reilly in February 1984, when it did not
concur with the remedial action proposed by the regulatory agencies for
each of the aquifers.
Hydrogeology

     In order to understand the problems at the Reilly Tar site it is
necessary to understand the hydrogeology in the area.  Coal tar released
from the site has contaminated four aquifers located beneath the site (see
Table 1 and the attached figures of the basin geology).  The aquifers that
are being studied under the current cooperative agreement with the EPA and
MPCA are the following:
                                 TABLE 1

                      Hydrogeology Below Reilly Tar
       Aquifer

(1) Drift/
     Platteville
(2) St. Peter

(3) Prairie du Chien-
     Jordan
Approximate
Depth (ft.)
  0-90
       Use
Upper Range of
Contamination
 (Total PAHs)
Private/Industrial    1000 ug/1 off-
wells                 site
              Municipal/Private     < 10 ug/1 off-
 90 - 200     driaking water wells  site

              Municipal drinking    10 ug/1 off-
 250 - 500    water wells           site
                                                             < 10 ug/1 is
                                                              estimated to
(4) Ironton-Galesville    700 - 750    Industrial usage       be on-site

                                       Municipal drinking
(5) Mt. Sijron-Hinckley    800 - 1100   water wells           Not detected


     Ground water contamination in each aquifer under the site is approxi-
mately ten times higher than the off-site concentration shown above.
Current Site Status

     The Prairie du Chien-Jordan Aquifer is the primary source of drinking
water for 110,000 people in St. Louis Park, EHina, Hopkins and all communities
adjacent to Minneapolis.  The City of Minneapolis depends exclusively on
the Mississippi River as its drinking water source and has considered
utilizing the Prairie du Chien-Jordan as its secondary source of water
supply in the future.  The deeper Mt. Simon-Hinckley Aquifer is the second
most extensively used drinking water aquifer for the area and it is utilized

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                         fl'&CC Plant Site
 Si "etf Aau'fer  —
Gienwood Snaie Confining Beo

    Si Peter Aquifer

  	 Basal St Pete' Confining 3»o
                                                                      :|  - Praine Ou Chien.JorOan AQj.'er

                                                                       — Si Lawrence-c'8nc3>va Con'mmg 3e2
                                                                       •- Ironton-Gaiesviiie Aou^'er
                                                                         Eau Claife ConfT.mg 3ec
       Sanaain Cmft-Pian«viMa
                                                                      "— St. Lawrence-Francon.a Confining 3ed
                                                                    	"— Ironton-Gaiesviile Aquifer
                                                                    f  ~~ Eau Cliire Confining 8*0

                                                                       T~ Mt  Sirnon-HmcKlev Aout'er
Surface Features ana Drift.Puneviile Aquifer
               Schematic  View  of Twin  Cities  Basin  Geology

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          Depth Below
         Land Surface,
            in Feot
              O-i
            100-
            200-
            300-
            400-
            500-
            600-
            700-
            800-
            900-
           1000-*
   Drift

Plarteviile Aquifer

 Con/inmg Bed'

  Si  P«ier
  Aquifer


Basal S( Ptiei
Confining Bed
                     Prai"6 du Cnien-
                     Jorajn Aquifer
                      St Lawrence-
                       r.-anconia
                      Confining 3ed
                    ifon-on-Gaiesville
                       Aquifer
                     Confining Bed
                      Mount Simon-
                     Hinckiey Aquifer
                                Stratigraphic
                                  Column
                 Hydrogeologic
                      Unit
      SUBSURFACE  GEOLOGY  UNDER
REILLY  TAR SITE,  ST.  LOUIS  PARK

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                                   - 6 -
 to such an extent that the Minnesota Department of Natural Resources is
 concerned about further significant appropriation of water fran this
 aquifer.  The St. Peter Aquifer, while it once was a major source of water
 supply, is new a minor source of municipal drinking water supply because
 of the better water quality of the Prairie du Chien.

     The upper-rest aquifers, the Drift and Platteville, have in the past
 provided potable water to numerous private wells, but with municipal
 supplies becoming available, they are no longer used for potable purposes
 to any significant extent.  However, there are still many private wells in
 the shallow aquifers which can be used for irrigation of lawns and gardens.

     The extent of contamination in each aquifer varies greatly.  No con-
 tamination has as yet been found in the Mt. Simon-Hinekley.  The hydrogeology
 of the site suggests that the St. Peter aquifer is contaminated.  Further
 sampling of wells near the site is expected to confirm this assumption.
 The area of contamination in the Prairie du Chien-Jordan extends east
 beyond Highway 169/100 and has the greatest potential public health impact
 due to the number of municipal water supply wells located just outside the
 presently known contaminated zone.  The spread of contamination usurps
 the aquifer's potential as the primary source of drinking water.

     Contamination of the Prairie du Chien-Jordan aquifer occurred by two
modes.  One is through direct contact of the aquifer with the coal tar
material found in W-23.  The material in this well has, for the most part,
 been removed.  Another mode of contamination is through the inadequately
 constructed multiaquifer wells that allow contaminated water frcm the
 upper aquifers to be transported along the outer diameter of the casing
 into the deeper cleaner aquifers.  These two mechanisms are the primary
 pathways of contamination of the Prairie du Chien-Jordan aquifer which
 resulted in the closure of 6 St. Louis Park wells and 1 City of Hopkins
 Well.

     Releases of PAH and related coal-tar distillate material to the envir-
 onment are still occuring.  The primary methods of contamination of the
 uppermost aquifer (Drift/Platteville Aquifer) is through the contaminated
 soil at the site and the bog south of the site which act as sources for
 migration into the ground water.  Contamination of the uppermost aquifer
 has been found to a depth of 90 feet in the bog area.  It seems that the
 contamination is not evenly distributed tnroughout the bog, rather, the
 area and depth of soil contamination appears to be representative of a
 channel into the bog area.  This is probably a consequence of the ditches
 used by Reilly to dispose of wastes.  As the contamination dissolves into
 the aquifer it moves east, southeasterly where it migrates through a bedrock
 valley into the Platteville aquifer and toward the St.  Peter Aquifer.


 Drinking Water Criteria for PAH

     The Minnesota Department of Health (MDH), since 1978, has been monitor-
 ing the water quality of the Prairie du Chien/Jordan aquifer for low con-
 centrations of coal tar compounds, particularly PAH.  Using the EPA published
 "Ambient Water Quality Criteria for Polynuclear Aromatic Hydrocarbons",

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                                   - 7 -
 t

October 1980, the MDH developed a limitation of 28 ng/1 for the sum of
carcinogenic PAH.  This represents a 10~5 health risk which, in theory,
inplies that one cut of 100,000 people who drink two liters of water cont-
aminated at this level for 70 years will contract cancer from this source.
The MDH recommended a limitation of 280 ng/1 for "other" PAH in drinking
water.  This was not based on a model; rather, the Department had concerns
over the relationship of "ozher" PAH to the activation of carcinogenic PAH,
the inability of the analytical method used at the time to distinguish
between certain carcinogenic and "other" PAH compounds and also over the
possibility that "other" PAH may still be toxic, tumor promoters and/or
nutagens.  In the context of this Record of Decision, carcinogenic compounds
and carcinogenic PAH compounds are defined as those compounds that, when
appropriately tested, produce cancer in at least one animal species.
"Other" PAH compounds or "other" compounds are those compounds that were
not tested for carcinogenesis and those compounds that, when appropriately
tested, did not produce cancer in at least one animal species.

     EPA recommends a target health risk of 10~6.  Using the same EPA
Water Quality Criteria document as the MDH, this value would correspond to
2.8 ng/1 of Benzo(a) Pyrene (BaP), the most potent carcinogen of the PAH
family found in the environment.  Therefore, EPA would prefer a technology
capable of achieving a limit corresponding to a 10~6 health risk, if it
is technologically feasible.

     Heterocyclic compounds less potent than BaP, have been measured
in the ground water and will, to some extent, be found in the finished
water.  Quinoline, for example, is less potent than BaP and has a 10~6
health risk concentration at 1,100 ng/1.  Reducing Quinoline and other
like carcinogens all to the level of reduction for Ba? results in con-
servative protection of the drinking water population's public health.
To do this the ratio of the sum of all the known carcinogenic corpounds
to the sum of all PAH and heterocyclic compounds found in the water supply
was determined.  These values vary but to be consistently conservative,
the sum of all known carcinogens is, at the most, 70 ng/1 based on the
historical data at SLP 15.  Based on the same data the total PAH and hetero-
cyclic compounds found in the water supply is, on the average, about 7000
ng/1.  Based on the variation of the data a ratio of carcinogenic compounds
to total PAH and heterocyclic conpounds is between 0.007 to 0.01.

     Using the more conservative ratio of 0.01, the concentration of
carcinogens found in the drinking water can be calculated.  The application
Of this ratio is also conservative because its use assumes that the effluent
characteristics of the PAH compounds from various treatment systems are
the same as the attenuation of these compounds by the aquifer they travel
through.  Another conservative assumption used in the rationale and applied
to the table below, is that the carcinogenic compounds measured in the
drinking water are as potent as BaP.  The use of this assumption accommodates
the uncertainty in determining the health risks due to the interaction of
carcinogens and known tumor promoters found in the water supply.

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                                   - 8 -
Sum of all PAH
and Heterocyclic
Compounds
Ratio of Health Risk
Compounds to Total
Compounds in the
Drinking Water Supply
Resulting Concentration
of Health Risk Compounds
in Treated Water
Risk
Based
on
BAP
2000 ng/1 0.01 20 ng/1 <10~5
1000 ng/1 0.01 10 ng/1 <10~5
280 ng/1 0.01 2.8 ng/1 <10~6
70 ng/1 0.01 0.7 ng/1 <10~6
<10 ng/1 0.01 0.1 ng/1 <10~7
     It has been suggested that the drinking water criteria for the City of
St. Louis Park be determined by examining background levels of PAH found in
other drinking water supplies locally and nationally.  These levels could
then be compared to levels obtained through various treatment technologies.

     While national data provide an important and useful tool, such data
are not necessarily determinative.  The National Contingency Plan (NCP)
requires the EPA to make site specific determinations of the appropriate
remedial action.  In the case of St. Louis Park, national data have been
carefully evaluated.  EPA rejects the concept that drinking water for St.
Louis Park need only be treated to the same PAH levels as the drinking
water supply of the highest level in the country.  To use the municipal
supplies with the highest PAH concentrations in the country as a bench
mark would ignore important local factors, such as the fact that prior to
closure of the wells in 1978 the residents of St. Louis Park were consistently
exposed over an undeterminable amount of time to abnormally high levels of
PAH in their drinking water.  Furthermore, it must be recognized that simply
because certain drinking water systems draw on surface supplies, which
typically have higher levels of PAH than ground water, does not imply that
those levels are appropriate.

     In the case of St. Louis Park, EPA recommends a conservative approach
to protection of public health from carcinogenic PAH found in the drinking
water aquifer.  The ramification of recommending a health risk of 10~6 for
carcinogenic PAH exerts a limitation for "other" PAH that would not exceed
90% of the drinking water systems thus far measured nationwide for PAH.
The range of values, depending on regression of existing data, would fall
between 150 to 300 ng/1 for "other" PAH.  The 10% of municipalities that
have been identified as having higher concentrations for "other" PAH all
draw their supplies from surface waters, not ground water.

     The comparison of the background levels of "other" PAH (less than 120
ng/1) found in neighboring cities and again to the criterion developed by
the MDH (280 ng/1) for "other" PAH, shows that these values are essentially
equivalent.  MDH is confident, and EPA agrees, that a level of approximately
280 ng/1 for "other" PAH, and 2.8 ng/1 for carcinogenic PAH will assure
less than or equal to a 10~6 health risk to the population.

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                                   - 9 -


ALTERNATIVES EVALUATION

     In August 1982, MPCA contracted with O^M Hill to complete the eval-
uation of water supply alternatives for St. Louis Park started under earlier
studies.

     The scope of this study was designed to fill in data gaps from previous
studies and to provide sufficient information for the MPCA to select a
water supply alternative for St. Louis Park.  The Scope of Work was modified
as the study progressed to compensate for new information and to effectively
mesh this study with other ongoing studies by MPCA.  The objectives of
this study included:

     o    Collect and analyze water sanples from nearby ccrmnnities to
          compare water quaJity goals for  St. Louis Park with other water
          supplies in the area.

     o    Develop water quality and quantity goals for restoring potable
          water supply capacity to the city of St. Louis Park.

     o    Develop and evaluate water supply alternatives which will restore
          water supply capacity to the City of St. Louis Park.  Prepare
          capital and O&M costs estimates for each alternative and discuss
          the relative advantages and disadvantages of each alternative
          considered, including no action.

     o    Perform a cost-effectiveness analysis of the water supply alter-
          natives.  Prepare a recommendation for implementation based en
          cost and technical considerations.

     o    Prepare a conceptual design and capital and O&M cost
          estimates for the full-scale system.


Surriary and Conclusions

    The following objectives were established tc provide a common basis
for developing and evaluating water supply alternatives for St. Louis
Park:

     o    Total supply shortfall of 3,400 gpm.

               1,200 gpm year-round usage for SLP 15/10.

               2,200 gpm "peaking" usage, three weeks per year, possibly
               utilizing the wells currently closed (SLP 7,9).

               restore pre-1978 capacity.

     o    Water quality equivalent to pre-1978 water quality in St. Louis
          Park.

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                                   -  10 -


     The alternatives that satisfied "these objectives were:

     o    Treatment of SLP-15/10 to provide potable water and start-up
          SLP-7 and -9.

     o    Install interconnection with City of Minneapolis water distri-
          bution system.

     o    Install new wells in the deeper uncontaminated Mt. Simon/Hinckley
          Aquifer.

     The no action alternative was also evaluated.

     An assessment of technologies was conducted to screen potentially
applicable technologies for removal of PAH and other coal tar derivatives
from ground water.  The following technologies were selected as most
appropriate for further evaluation and bench-scale test work:

     o    Oxidation Processes

                Ozone (03).
                Ozone/Ultraviolet (O$/UV).
                Hydrogen Peroxide/Ultraviolet (H202/UV).
                Chlorine Dioxide (C102).

     o    Adsorption Processes

                Granular Activated Carbon.
                Powdered Activated Carbon.
                Macroreticular Resin.

     o    Membrane Processes

                Reverse Osmosis.
                Ultrafiltration.
     SLP 15/10 was started up and well water was passed through the
existing iron removal treatment system in September 1982.  Water sanples
were obtained at various points in the treatment system and analyzed for
PAH.   Eighty percent removal of PAH was measured across the system, but
effluent did not meet MDH's treatment goal of 280 ng/1 total "other" PAH.
Bench-scale tests indicated that the unit operations employed at the existing
treatment system were ineffective in removing most PAH compounds.   To.
resolve the discrepancies between the first onsite test and the bench-scale
results, a second onsite test was conducted in December 1982.  The results
of the second onsite test corresponded well with bench scale results.  It
was concluded that the unit operations employed at the existing treatment
system are not adequate to provide PAH removals for a potable water treatment
system at SLP 15/10 nor were they reliable.

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     Only three technologies tested during the bench-scale testing program
met the MDH treatjnent goals:

     o    Granular Activated Carbon (SVC).
     o    Ozone/Ultraviolet (O^/UV).
     o    Hydrogen Peroxide/Ultraviolet  (H202/UV).


     Conceptual designs were prepared for full-scale treatment systems using
each of the above technologies.  Comparative capital and annual O&M costs
were estimated for each system, and the  features of each system were examined.
Based on both cost and technological considerations, GAC was selected for
pilot-scale testing.  A 42-day pilot-scale test of GAC was conducted at SLP
15/10.  Based on the results of the pilot test, design criteria were developed
for a full-scale GAC treatment system at SLP-15/10.  The pilot-scale test was
adequate to provide system design criteria, but could not be run long enough
to accurately define carbon adsorption capacity in a full-scale system.
Based on information gained in bench and pilot-scale testing, a range for
expected carbon adsorption capacity was  developed.

     Powdered activated carbon (PAC) did not meet the criteria for bench
scale testing and thus was not evaluated in detail.  It had substantially
the same construction cost (5600,000) for mixing tank, clarifier and piping
as the GAC but the O&M cost to meet the  drinking water levels was impractical
to consider due to the high and inefficient use of carbon.  Since the amount
of PAC required is higher than GAC, use  of PAC will result in higher O&M
costs and increase the risk that contaminants would pass through before
adjustments were made.  Furthermore, substantial amounts of carbon residue
would be generated and removed on a frequent basis thereby increasing the
maintenance cost of the system when compared to GAC.  Hydrogen peroxide/
ultraviolet treatment was evaluated and  eliminated due to high capital and
O&M costs.  Capital cost was $1.158 million and annual O&M cost is estimated
at $281,000 to reach the recommended treatment level.  The present worth of
this technology was $3.806 million, significantly higher than GAC or ozone.

     After completion of the treatment technology review and testing
program, the following alternatives were identified for detailed evaluation:

     o    Alternative No. 1 - Treat SLP  15/10 with Granular Activated Carbon
          for Potable Supply and Start Up SLP-7 and -9.

     o    Alternative No. 2 - Install Interconnection with City of Minneapolis
          Water Distribution System.

     o    Alternative No. 3 - Install Wells in Mt. Simon/Hinckley Aquifer.


     The no action alternative was eliminated because of the documented
contamination above the State and EPA's  reconmended targets at the drinking
water wells, the consequent water supply shortfall, and the knowledge that
the plume is continuously spreading toward other water supplies.  Return of
SLP 15/10 to operation would help retract the plume and when combined with
proposed future remedial measures it would protect other cities.

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                                   - 12 -


Discussion of Alternatives

     Costs for both treatment and non-treatment alternatives were developed
and are shown in Table 2.  The costs for treatment alternatives were developed
over a range of treatment levels that correspond to various health risks.
The treatment levels vary from sub organoleptic (i.e., beneath taste and
odor) concentrations of 3000 to 4000 ng/1 of other PAHs down to less than
10 ng/1.  The associated risks are shown on Table 2.  These cost estimates
indicate that at the higher treatment range ozone is less expensive than
granular activated carbon.  As the treatment levels decrease to the target
levels recommended by the State and EPA granular activated carbon becomes
the less expensive alternative.

     It can be seen that costs for deeper wells and for treatment of the
Prairie du Chien/Jordan are similar, with treatment to the recommended PAH
level slightly cheaper.  This is due to the high expense of drilling to
the Mt. Simon-Hi nek ley Aquifer which the City completed in the summer of
1983.  The cost for one well was approximately S6(JO,OGO due to the geologic
factors that makes drilling and casing expensive.  Furthermore, it is
probable that iron removal facilities will be necessary for water taken
from the Mt. Simon Hinckley Aquifer.  The cost of these facilities (estimated
at $400,000 per well) is not included in Table 2.

     Installation of potable water supply wells in the Prairie du Chien/
Jordan aquifer upgradient of the contamination was considered, however,
costs would be similar to installing wells in the Mt. Simon-Hinekley, and
in addition, installing new wells upgradient of the plume woula tend to
retract the plume and pollute other SLP water supply wells.

     Based on the above cost evaluation, treatment of the Prairie du
Chien/Jordan aquifer is the least costly alternative that meets the remedial
action objectives.  Either treatment with ozone or granular activated
carbon will satisfy the objectives.  However, granular activated carbon
treatment is recommended for the following reasons:

     (1)  It can be operated over a wide range to remove carcinogenic and
          other compounds to below detection limits, 1-2 ng/1 (corresponding
          to less than 10~^ health risk), or up to higher levels such as
          the sub taste/odor threshold, of 3000-4000 ng/1 of other PAH.
          At the limits of 2.8 ng/1 for carcinogenic PAH, pilot plant data
          shows that no other PAH will be detected in the treated water.

     (2)  It can accept slug loads without upset and with no need to adjust
          operation of the system.  System regeneration is predictable.

     (3)  It can be maintained with less operator oversight than other
          competitive technologies.

     (4)  There is no generation of by-products which could become health
          risks.

     (5)  GAC is a proven technology, preferred by the EPA-Office of Drink-
          ing Water, and represents the best available technology for
          this problem.

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                                                   Table 2
                                        COSTS OF ALTERNATIVES (x 1000)
CARCINOGENIC      TOTAL
   HEALTH         PAH
    RISK          nq/I

A. Treatment Alternatives

   10-5 to 10-6   2000
   10~5 to 10-6   1000
 < 10-6 to 10-6    280
 < 10-6           < 70
 < 10~6           < 10

B. Non-Treatment Alternatives

   Hookup to Minneapolis
   Drill Deeper Wells
OZONE
PRESENT
CAPITAL O/M WORTH
374 132 1,610
459 175 2,108
709 183 2,434

GAC
PRESENT
CAPITAL O/M WORTH
633 161 2,150
633 173 2,263
633 188 2,405

ALTERNATE SUPPLIES
PRESENT
CAPITAL O/M WORTH

250 833 8,102
1,870 111 2,916
   NOTES:

   1.  Present worth cost determined at  10%, 30 years.

   2.  2000 ng/1 = Sub Orrjanoleptic Threshold.

   3.  GAC and 03 costs are approximately constant for limits < 280 ng/1.

   4.  03 costs include $60,000 for pilot work.

   5.  Health risk of carcinogenic compounds based on break through of non-carcinogenic
       compound:; associated with non-carcinoqonic limit (Based on RaP at 2.8 ng/1 = 10"6).

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                                   - 13 -
Ozone technology, in addition to being slightly more expensive at the
recommended treatment level/ is less desirable for use in a drinking
water system for several reasons:

     (1)  Ozone generation and dosage is proportional to influent concen-
          trations which will vary with operation of the system; therefore,
          the use of conservative (high) dosages tend to result in increased
          costs of operation.

     (2)  If a slug load passes through the system it would not be totally
          treated, and by-products with possible health risks could be
          generated according to a review of relevant literature.

     (3)  If influent concentrations exceed design criteria, the contamin-
          ants would pass through the system and adjustment of the system
          could not be made until analytical results are received.  Ihis
          would probably take 1 to 2 weeks, during which time contaminants
          would enter the drinking water system, possibly exposing the
          population to health-risk related compounds.

     (4)  Two different ozone treatment systems were compared, for the
          various degrees of treatment.  For limitations between 4000
          ng/1 and 1000 ng/1 only ozone is necessary.  For less than
          1000 ng/1 ozone with UV lamps is necessary.  Ozone is cost-
          competive to approximately 1000 ng/1.  Below that, Q^C is
          cost-effective.  If ozone were implemented as a treatment
          technology, for levels above 1000 ng/1, and subsequently the
          regulatory agencies determined lower limitations were necessary,
          the installed ozone treatment system could not be retrofitted
          to meet the more stringent limits.


For economic reasons, ozone would be suitable and preferred for a discharge
to surface water.
RECOMMENDED ALTERNATIVE

     Section 300.68(j) of the National Oil and Hazardous Substances
Contingency Plan states that EPA shall select the cost-effective alterna-
tive (i.e. the lowest cost alternative that is technologically feasible
and reliable and which effectively mitigates and minimizes damage to and
provides adequate protection of public health, welfare, or the environment).

     EPA has determined that the treatment of St. Louis Park well SLP-15/10
with granular activated carbon will achieve the above requirements (See
Figure 9-1 for system diagram).  Other alternatives were evaluated that
would provide adequate public health protection but these are not recommended
for the following reasons.  Interconnection with the City of Minneapolis
would provide an adequate supply and has the lowest capital cost of all
the alternatives.  However, the cost of purchasing water over time causes
the present worth cost to be significantly higher than any alternative.

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                                                                                                        VEHICLE
                                                                                        TO EXISTING
                                                                                        SLP 16
                                                                                        TREATMENT
                                                                                        SYSTEM
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                                   - 14 -


     Installation of deeper wells to the Mt. Simon-Hinekley aquifer is only
oll^.Lly :r,cre expensive than the recommended alternative.  This alternative
is technically less complex than the recommended alternative since it is
not dependent on a treatment system to remove PAH compounds.  However, this
alternative was not recommended since the experience gained when the City
installed a new well in the Mt. Simon-Hinekley aquifer showed that the
quantity of ground water was below the original expectation.  This indicates
that this aquifer may not be capable of providing the necessary quantity
of ground water over a long-term.  The State recognizes this situation and
is concerned about future significant withdrawal of water from this aquifer.
Therefore, this alternative is not recommended.

     The alternative of treating contaminated water from the Prairie du
Chien aquifer is the least expensive alternative to provide an acceptable
water supply and has the additional advantage of mitigating the existing
plume of contamination.  Pumping and treatment of well SLP-15/10 will act
as a barrier to contamination and allow the renewed use of wells SLP-7
and SLP-9 for drinking water use.  This alternative will also help control
migration of the plume and remove contamination from the environment.  In
addition, pumping and treatment of SLP-15/10 will probably be a component
of a future remedial action to control migration of the entire plume of
contamination.  That action will be addressed in a future Record of Decision;
however, selection of the recommended action for treatment of SLP-15/10
will reduce the cost of the future plume control action, if approved.

     The recommendation for use of granular activated carbon rather than
ozone is based on its lower cost and higher confidence to consistently
meet the required treatment level.  EPA's reccnrnended target for carcinogenic
PAH (based on benzo (a) pyrene) is 2.8 ng/1 which corresponds to a 10~6
risk factor.  Use of granular activated carbon is also recommended over
ozone since GAC has been proved to be reliable over a wide range of
operating conditions and is considered best available technology for water
supply treatment.  Therefore, granular activated carbon treatment provides
the least cost with the highest flexibility and reliability of treatment.

     Design and construction of a GAC system is expected to take 8 months
after initiation of design.  Additional funds for this task are not
necessary at this time since the MPCA is able to reprogram funds available
in the existing cooperative agreement.  Additional funding will be requested
in the future for further remedial action, as appropriate.  The MPCA and
Region V consider the construction of a drinking water system the highest
priority for cleanup of the Prairie du Chien aquifer.  Other tasks already
approved and funded i.e., feasibility study for the soils and multi-aquifer
well closing can be initiated this fall.  However, due to the amount of
data produced by Reilly Tar in its report, "Recommended Plan for a
Comprehensive Solution of the Polynuclear Aromatic Hydrocarbon Contamination
Problem in the St. Louis Park Area," and data produced by other sources,
the scope of any future feasibility study for source control will be
substantially modified.  The design of the water treatment system can
commence immediately upon approval of the Record of Decision since
Hill is still under contract with the MPCA for this work.

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                                   - 15 -
  t
.. r

COST ESTIMATE

     The total capital cost of GAC treatment is $633,000.  Piping to SLP 10
and hookup of SLP 10 to SLP 15 is approximately $49,000.  Design of the
system is estimated at $68,000, and the first year O&M Cost is estimated at
$188,000.

     Therefore, the total capital cost estimate is $750,000.  The MPCA can
reprogram this amount with existing funds originally obligated by EPA for
IRM/FS work at the site.  The first year O&M cost of approximately $188,000
will be requested in a subsequent amendment.


OPERATION AND MAINTENANCE

     The first year operational cost for which funding is requested is
$188,000.  The State of Minnesota accepts the oversight responsibility of
monitoring the effectiveness of the system.  The State will assure the
future O&M as required by section 104(c)(3) of CERCLA, but EPA and the
State may seek to transfer that responsibility to either Reilly or the
City, or both, through enforcement action or negotiations.


NEXT STEPS

     Milestones                                      Date

     Sign ROD                                        May 1984

     Amend CA for Design and Construction            June 1984

     Complete Design                                 August 1984

     Complete Construction                           June 1985


FUTURE REMEDIAL ACTIONS

     Following completion of the feasibility study being conducted by the
State, another ROD will be prepared to address the following possible
actions:

     (1)   Off-site remedial measures to control contaminated ground water
          plumes in multi-aquifers beneath the site, and

     (2)   Source control measures to minimize the release of hazardous
          substances from the site.

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                                   -  16 -
*'

 PUBLIC RESPONSIVENESS SUMMARY       . "

     The MPCA has attempted to keep the residents of the affected area well
 informed and  has made positive effort to respond to their concerns.  For
 this purpose, the  Agency hired a community relations coordinator during
 the course of the RI/FS work.

     The public was  informed of the initiation of the drinking-water
 feasibility study at a public meeting held on February 15, 1982, at the
 public high school in St. Louis Park.  Approximately 100 people attended
 the meeting.

     A second public meeting at the high school held on May 16, 1983,
 reported the  results from the feasibility study.  An audience of more than
 100 people heard presentations by Executive Director, Sandra Gardebring
 and Michael Hansel of the MPCA, Commissioner Mary Madonna Ashton and David
 Gray of the Minnesota Department of Health (MDH), Paul Bitter of the U.S.
 EPA and representatives of CH2M-Hill and Barr Engineering, the project's
 contractors.  TVo fact sheets were distributed at the meeting covering the
 background of the problem and the feasibility study results.

     Questions and comments about the feasibility study were solicited at
 the public meeting and thereafter.  In addition to responding to telephone
 calls  from concerned citizens and questions from news reporters, the MPCA
 has endeavored to keep the public informed of progress in several ways.

     An MPCA  Board - appointed citizens advisory committee made up of local
 residents has met monthly since the simmer 1983 to provide regular communi-
 cation between the MPCA and the local community.  Members of that organiza-
 tion have heard from the MPCA, the MDH and Reilly's Technical Consultants,
 ERT, and deliberated the issue.

     Other efforts to inform the community have included the publication
 of feasibility study results and articles on advisory commitee progress
 in the city news letter sent to every resident of St. Louis Park on a
 bi-monthly basis.  The St.  Louis Park public library has received a copy
 of the feasibility study report, sheets, and an advisory committee statement.
 The availability of the fact report was announced on the City's "bulletin
 board" on cable television.

     Because  the meeting announcing the results of the feasibility study
 preceded a Reilly-sponsored meeting reporting the company's recommendations,
 many comments received in the time period immediately following the meeting
 considered the differences in the proposals and the progress of the litigation.
 A few  comments urged the MPCA to consider the ERT report carefully, and
 considerable  MPCA and U.S. EPA staff time has been spent examining ERT's
 work inclusions.

     Questions at the public meetings fell into three main categories,
 (1) those considering the carbon filter system and drinking-water safety,
 (2) those regarding other remedial actions that may be necessary and,
 (3) those asking about cleanup and cost and the progress of the litigation.
 For instance, residences wanted to know how carbon was able to remove

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                                   - 17 -
  %

contaminates from the drinking water'and what happened to the spent carbon.
T^c technology of carbon filtration and regeneration for reuse for other
purposes was explained.  Residents were assured that the filtered water
would be tested monthly with a 3- or 4- day turnaround on test results,
in response to questions about "breakthrough."  One questioner wanted to
know whether the carcinogenic PAH were readily adsorbed, as well as the
other PAH, to which the response was "yes".  A few questions regarded the
PAH criteria level, which the MDH representative explained represents an
expected 10~5 risk level.  No support was expressed for the other alternatives
considered by the feasibility study, including the connection with Minneapolis
Water System or deep wells.

     Concerns on other remedial measures included questions on the rate of
groundwater movement, multi-aquifer wells and other remedial action that
might be anticipated.  It was explained that the study of the groundwater
was not complete but the using of granular activated carbon on well 15/10
was part of an overall plan to control groundwater movement and the spread
of contamination.  The results of the well survey and progress on well
abandonment were described.  It was explained that a prohibition on new
multi-aquifer wells will prevent the creation of new problems.

     Several comments were received urging the agency to continue with its
litigation efforts in expressing the opinion that the company should bear
the cost of cleanup.

     At the time of the public meeting and in the time that followed,
support for the carbon filter system has been strong.  A major concern
remains the question of the City having to return contaminated wells to
service, as it did during the summer of 1982.  A water conservation committee
was established by the St. Louis Park committee counsel to recommend reduced
water usage (in addition to the City's ordinance regulating loss due to
sprinkling during the summer months).

     The City Council has adopted a resolution encouraging the MPCA to pro-
ceed with the carbon filter system.  The Citizen's Advisory Committee
reached consensus on a statement including similar reports.  Candidates
for City Council seats in the fall of 1983 elections all expressed support,
as has the area's legislative delegations.

     News media and public criticism has focused primarily on the delay in
implementation.  The community is well educated in the drinking-water
problem experienced by the City over the years, and carbon filtration
appears to be not only accepted but desired by the public.

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