PB95-963137
EPA/ESD/R08-93/103
March 1995
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
Smuggler Mountain
(O.U. 1), Aspen, CO
6/10/1993
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EXPLANATION OF
SIGNIFICANT DIFFERENCES
SMUGGLER MOUNTAIN
OPERABLE UNIT 1
ASPEN, PITKIN COUNTY,
COLORADO
United States
Environmental Protection Agency
Region VIE
June 1993
INTRODUCTION
The purpose of this document is to explain the
significant differences between the Smuggler
Mountain Superfund Site cleanup remedy selected
by the U.S. Environmental Protection Agency
(EPA) in the Record of Decision (ROD)
as modified by the 1989 and 1990 Explanations of
Significant Differences (ESDs) and 1991 Minor
Modification. It addresses how the remedy will be
implemented in light of additional public comment,
including the public health recommendations of the
Technical Advisory Committee (TAG).
MAJOR CHANGES IN THE REMEDY THAT ARE PROPOSED
IN THIS EXPLANATION OF SIGNIFICANT DIFFERENCES
The Operable Unit 1 (OU 1) remedial action, selected in the ROD and modified by the previous ESDs and
minor modification, is being changed as follows:
1) The Pitkin County Health Department will
institute a blood lead surveillance program
for young children.
2) The berm area will be capped with clean
soil and revegetated. Common-use areas
of exposed mine waste, including the
Mollie Gibson Park, will also be covered,
revegetated and monitored.
3) Vegetable gardens should be planted in at
least 12 inches of clean soil.
4) The Aspen/Pitkin Environmental Health
Department will evaluate site construction
projects or land use changes to determine
whether they present a threat of soil
exposure to young children.
5) EPA will make a final determination
regarding remediation of the OU 1
residential soils. This determination will
be based on EPA's review of lead
speciation studies that have been
completed, bioavailability studies that are
to be completed in 1993-1994, and review
of the Pitkin County Health Department's
blood lead and dust monitoring program.
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INTRODUCTION
(continued)
Undex-Section 117 of the Comprehensive
Environmental Response, Compensation, and
Liability Act (CERCLA), as amended.by the
Superfund Amendments and Reauthorization Act,
. EPA is required to publish an Explanation of
Significant Differences when significant changes
are proposed to the previously selected remedy.
The .ESD shall be placed in the administrative
. record fi],e for the site. This ESD, as well as the
ROD, previous ESDs, the TAC Report, and major
documents pertaining to activities at the Smuggler
Site are available at the Pitkin County Library, the
Aspen/Pitkin Environmental Health Department,
and the EP A Superfund Records Center in the
Denver EP A office.
SITE HISTORY AND CONTAMINATION
PROBLEM .
The Smuggler Mountain Superfund Site is located
in the northeastern portion of Aspen on the . .
southwestern flank of Smuggler Mountain. Waste
rock and tailings from mines on Smuggler
Mountain are exposed, covered or mixed .with
native soils across the site. The site is largely
developed with large and small condominium units,
mobile home parks, a tennis club, and numerous
single family residences.
Soil analyses in the early 1980's, conducted first by
residents and then later by EPA and the Potentially
Responsible Parties (PRP's), identified
concentrations of lead as high as 65,000 parts per
million (ppm); well above EPA's cle:mup level of
1,000 ppm. Elevated levels of cadmium were also
found in the soils. The site was placed on the
National Priorities List (NPL) in May 1986. A
ROD was issued in September 1986, and a remedy
for soil cleanup was selected.
SUMMARY OF THE RECORD OF DECISION
The objectives of the remedy selected in the 1986
ROD were to isolate waste materials with lead
concentrations greater than 1,000 ppm by
requiring:
1)
removal and disposal of soils and tailings
with lead concentrations greater than 5,000
ppm in an on-site repository,
2)
capping of soils with lead concentrations
between 1,000 and 5,000 ppm with 6 to 12
. inches of clean soil and revegetation.
3)
continued monitoring of the ground water,
4)
provision of an alternate water supply for
residences with domestic wells and,
5)
operation and maintenance of the remedy
through regular inspections as well as
through land use restrictions, known as
institutional controls.
The 1986 ROD selected a soil cleanup level for
lead concentrations exceeding 1,000 ppm based on
information in the Endangerment Assessment and
Remedial Investigation/Feasibility Study and on
recommendations by the Agency for Toxic
Substances and Disease Registry (ATSDR).
The ROD divided the Site into two OUs: OU 1 is
mostly residential; OU 2 includes the mine site on
Smuggler Mountain. The ROD also required
ground water monitoring as a result of suspected
ground water contamination. Further consideration
of the ground water was deferred to OU 2.
However, current site conditions suggest that the
ground water contamination identified earlier was
due to the high natural metals content in the soils,
or the result of well materials. Accordingly,
ground water remediation will not be included in
this ESD or as part of any response action at the
site.
The remedy selected in the ROD was solely for OU
1. During the remedial design, additional technical
information showed that the selected remedy was
not implementable. The ROD was modified in the
March 1989 ESD. This ESD was issued to.
accommodate the unexpectedly high volume of soils
with lead concentrations over 1,000 ppm. EPA
planned to remove the top two feet of soils
containing more than 1,000 ppm lead in the
residential areaS and added an additional on-site
repository-for the extra volume of soil.
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The Aspen community was concerned with the
changes and submitted an alternative proposal to
EPA for site clean up. This prompted EPA to
c~e the remedy in a second ESD issued in May,
1990. from two feet to one foot of soil removal,
and the placement of a geotextile liner between the
clean soil, containing less than 250 ppm lead, and
. the contaminated soil. Several elements of the
remedy proposed in the March 1989 ESD were
changed in the May 1990 ED. These changes
consisted of a greater reliance on local land use
restrictions known as Institutional Controls (ICs)
and removal of six inches of contaminated soil in
the Hunter Creek and Centennial condominium
areas. However, one foot of soil would still be
removed elsewhere on the site.
The May 1990 ESD relied more on lCs. Pitkin
County adopted lCs in May 1991, but they were
repealed based on citizen concern about the need
for any remedy.
EP A issued a Minor Modification to the remedy in
October 1991 that recognized that landowners could
implement land use controls rather than local
government. The October 1991 Minor
Modification provided for implementation of
institutional controls by the adoption and
enforcement of local ordinances by Pitkin County
or the City of Aspen, by compliance with EP A
approved Operation and Maintenance plans by
private parties or by the use of EPA's enforcement
authority .
Some citizens contended that the cleanup, with
heavy equipment and dust, would be more
~azardous than living with the health risk at the
site. To address the community's concerns, the
T AC, an independent panel of six nationally
recognized lead experts and three technical
advisors, was convened in October 1992. The
TAC released a final report in January 1993.
SUMMARY OF THE TAC REPORT
The TAC published a final report in January 1993.
EP A reviewed this report and accepted the
recommended public health actions. The TAt
recommended that:
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1)
A program of blood lead surveillance be
instituted for young children.
2)
The highly cont~min~ted berm area be
capped with clean soil, revegetated, and be
monitored to ensure its integrity. The
Mollie Gibson Park and other common-use
areas of exposed mine waste be covered
and monitored.
3)
Vegetable gardens be planted in at least 12
inches of clean soil.
4)
Soil testing be made available to residents
of the Site upon request.
5)
The AspenlPitkin Environmental Health
Department evaluate proposed site use
changes for possible soil exposure . changes
to young children.
6)
If studies demonstrate that lead-bearing
materials at this Site have or can be made
to have very low bioavailability, the above
actions/recommendations be reviewed and
perhaps modified.
CURRENT EXPLANATION OF SIGNIFICANT
DIFFERENCES
1)
The Pitkin County Health Department will
institute a blood lead surveillance program
for young children and an indoor dust
sampling program. Neither program was
part of the May 1990 ESD.
2)
Pitkin County will cap the berm with clean
soil and revegetate and maintain it.
Common-use areas of exposed mine waste,
including the Mollie Gibson Park, will also
be covered, revegetated and monitored.
The May 1990 ESD required removing the
contaminated berm material and depositing
it in a secure repository. The primary
goal of the ROD and its previous
modifications was to break the exposure
pathway between humans and the
cont~mjn~ted material. This change can be
implemented without compromising that
goal. Inspection and maintenance will be
necessary to ensure the effectiveness of
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this remedy.
3)
Vegetable gardens will be planted in at
-- least 12 inches of clean soil. In the May
1990 ESD, flowers and vegetables were to
be planted in raised-bed gardens that were
at least six inches above the soil and
vegetative cover. Together raised-bed
gardens and one foot of clean soil were to
provide at least 18 inches of clean soil.
EP A has determined that 12 inches will be
sufficient to break this potential pathway of
exposure.
4)
The Aspen/Pitkin Environmental Health
Department will evaluate proposed
construction projects or land use changes
for the threat of soil exposure to young
children. EP A will oversee the
Department's efforts. The May 1990 ESD
called for both EPA's and the Aspen/Pitkin
Environmental Health Department's
evaluation.
5)
Lead speciation studies for the Smuggler
Site have been completed, and
bioavailability studies will be completed in
1993-1994. Upon completion of these
studies and review of the blood lead and
dust monitoring performed by the Pitkin
. County Health Department, EP A will
determine the need for further residential
soils cleanup. If EP A determines that th.e
remedial actions in the May 1990 ESD
need to be implemented, the TAC will be
reconvened to review and comment on the
findings of these studies. Based upon the
TAC's review and additional public
comment, EP A will make a final .
determination regarding cleanup of the OU
1 residential soils.
6)
Ground water monitoring will cease at OU
1. A ground water corrective action will
not be implemented at the site.
PROTECTIVCNESSOFTHEREMEDY
EP A has determined that the remedy included in
this ESD is sufficient to protect human health and
the environment. A final determination of the
protectiveneSs of these response actions and the
need to implement the additional OU 1 response
actions contained in the May 1990 ESD will be
made in the future. Completion of presently
ongoing bioavailability studies and monitoring of
the Aspen residents is necessary for EPA's final
determination. This determination will be made in
accordance with the periodic review provision of
CERCLA, Section 121(c).
SUPPORTING AGENCY COMMENTS
The Colorado Department of Health has reviewed
the significant differences contained in this 1993
ESD and has provided comments to EP A. The
Colorado Department of Health supports
implementation of the remedy as presented in this
ESD.
STATUTORY DETERMINATIONS
EP A has evaluated the cleanup presented in this
ESD against nine criteria for acceptance.
1) Overall Protection of Human Health and
the. Environment. EP A has determined that the
remedy will be protective of human health and the
environment because it breaks the exposure
pathway by preventing direct contact with
contaminated soils and tailings. This remedy
complies with the recommended health advisory by
ATSDR for cleanup of soils CODt~m;nated with
lead. This remedy requires remediation of certain
common-use areas where mine waste materials are
exposed.
2) Compliance with Applicable or Relevant
and Appropriate Requirements (ARARS). The
cleanup meets the statutory and regulatory
evaluation criteria for selection of a
remedy. Because hazardous substances will remain
at the site, EP A will conduct periodic inspections
of the site to ensure that the remedy. remains
protective of human health and the environment.
EP A is required to conduct such reviews under
Section 121(c) of CERCLA and the NCP.
3) Short-Term Effectiveness. During
construction of this remedy. dust levels may
increase slightly. Stringent health. and safety
measures and monitoring will m;n;m;7~ dust levels
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and ensure the safety of both the workers and the
residents.
4) - Long-Tenn Effectiveness and
Pennanence. Contaminated material will remain
onsite after completion of the remedy. The long-
term effectiveness and permanence of the remedy is
ensured by monitoring and maintenance of .the
clean soil cap and vegetative cover.
5) Reduction of Toxicity, Mobility, or
Volume through Treatment. Because treatment
of the principal threats at the site was determined to
not be practicable, this remedy does not satisfy the
stacutory preference for treatment as a principle
element of the remedy. However, this revised
remedy utilizes permanent solutions and alternative
treatment technologies to the maximum extent
practicable for this site.
6) Implementability. EP A has determined
that the remedy is fully implementable. The
materials and services needed are available, and
the remedy is technically and administratively
feasible.
7) Cost. The cost of implementing the
remedial actions identified in this ESD is estimated
to be $ 1.3 million. The remedy is considered to be
cost effective.
8) State Acceptance. The Colorado
Department of Health has reviewed and accepts the
remedy.
9) Community. Acceptance. The community
accepted the recommendations of the T AC. The
remedy implements those recommendations.
SCHEDULE FOR SITE CLEANUP
Implementation of this portion of the OU 1 remedy
is expected to be initiated during the 1993 and 1994
construction seasons.
FOR MORE INFORMATION
All major documents pertaining to the Smuggler
Site are available at the following information
repositories:
Aspen/Pitkin Environmental Health Department
130 S. Galena St.
Aspen, CO 81611
(303) 925-2020
Pitkin County Library
120 E. Main st.
Aspen, CO 81611
(303) 925-7124
EP A Superfund Records Center
999 18th St., Suite 500
Denver, CO 80202
(303) 293-1807
OUESTIONS about this site should be directed to: .
Rob Henneke,
Office of Extemal Affairs (80EA)
U.S. Environmental Protection Agency
999 18th. Suite 500
Denver, CO 80202
TELEPHONE: 303-294-1129
FAX: 303-294-7665
or.
Brian Pinkowski
Project Manager (8HWM-SR)
U.S. Environmental Protection Agency
999 18th, Suite 500
Denver, CO 80202
TELEPHONE: 303-293-1512
FAX: 303-293-1238
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION VIII
"9 18th STREET - SUITE 500
DENVER, COLORADO 80202-2466
June 2, 1993
Ref: 8HWM-SR
MEMORANDUM
TO: Robert L. Duprey, Director
Hazardous Waste Management Division
FROM: Diana Shannon, Chief
Superfund Remedial Branch
SUBJECT: Explanation of Significant Differences to the ROD for the Smuggler Mountain
Superfund Site, Operable Unit 1
Attached is the Explanation of Significant Differences (ESD) to the 1986 Record of
Decision (ROD) and the remedy which will be implemented at Operable Unit 1 of the
Smuggler Mountain Superfund Site.
The objectives of the ROD signed in 1986, as amended by the 1989 and 1990 ESDs
and Minor Modification, were to isolate waste materials with lead concentrations greater than
1000 ppm lead. The isolation of lead contaminated soils was to be accomplished by
excavation and on-site disposal. The remedy was to include exposed soils near the
residential areas as well as excavation and disposal of contaminated soils from individual
residential lots.
I recommend that the OU1 remedial action, as contained in the ROD, as amended, be
changed to incorporate implementation of the following additional and/or revised items:
1) The Pitkin County Health Department will institute a blood lead surveillance program
for young children. The Health Department will also implement a indoor dust
sampling program concurrent with the blood lead monitoring.
2) The berm area will be capped with clean soil and revegetated. Other common-use
areas of exposed mine waste, including the Mollie Gibson Park, will be covered,
revegetated and monitored.
3) Vegetable gardens should be planted in at least 12 inches of clean soil.
4) The Aspen/Pitkin Environmental Health Department will evaluate site construction
projects or land use changes to determine whether they present a threat of soil
Printed on Recycled Paper
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exposure to .young children.
5)
'Lead speciation studies' have been completed and bioavailability studies are to be
completed in 1993-1994. EP A, will review these studies and the monitoring
performed by the Pitkin County Health Department. If EP A determines that
additional work may be necessary, the TAC will be reconvened to review the fIndings
of these additional studies as part of an additional opportunity for public comment.
EP A will make a fmal detennination regarding the OUI residential soils. .
"-.... "
, ''''','
", . . These chariges' are the result of additional public comment and a reconsideration of
the eff~veness of the ROD's remedial goals.
The potential for ground water contamination was identifIed during the early
investigations. However, current site conditions suggest that the groundwater contamination
identifIed earlier was background contamination due to the high natural metals content in the
soils, or the result of well materials. My staff does not believe that groundwater: .
contamination which resulted from mining activities is likely to be a health threat now or in
the future. Accordingly, no groundwater remediation is included in this ESD.
The State of Colorado has reviewed this ESD and is in agreement with the remedy
described therein. Should you need further information or require a briefmg, please notify
me. Thank you.
Concurrence:
~f{bQ
, Date
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