Eureka Mills Superfund Site
Eureka, Utah
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY • REGIONS • MARCH 2011
Operable Unit 4 Groundwater, Surface Water, and Ecological Risk Proposed Plan
Introduction
The U.S. Environmental Protection Agency (EPA) and the Utah
Department of Environmental Quality (UDEQ) request com-
ments on the proposed plan for Operable Unit 4 (OU4) of the
Eureka Mills Superfund Site (site). The proposed plan pre-
sents the EPA's and UDEQ's preferred alternative for OU4,
which addresses:
• Human health risks from site groundwater
• Human health risks from site surface water
• Ecological risks within undeveloped areas of the site
EPA studied the impacts of historical mining on groundwater,
surface water, and the environment. Given EPA's role on
these studies, EPA is the lead agency for the site and is issuing
this proposed plan. UDEQ is the support agency for the site
and has been consulted on this proposed plan, as required by
the Comprehensive Environmental Response, Compensation,
and Liability Act (CERCLA), commonly referred to as Super-
fund.
As an aid to the reader, we have included a acronym list at
the end of this document.
This proposed plan provides an overview of:
• Site background and history
• Site contamination and risk
• Activities that EPA has completed at the site
• The preferred response action for OU4
EPA, in consultation with UDEQ, will select a final remedy for
the site after reviewing and considering community input sub-
mitted during the 30-day public comment period. EPA and
UDEQ may modify the preferred alternative based on new
information or public comments.
EPA is issuing this proposed plan as part of its public participa-
tion responsibilities under CERCLA Section 117(3) and Section
(Continued on page 2)
MARK YOUR CALENDAR
PUBLIC COMMENT PERIOD:
Monday, April 4, 2011 to Tuesday, May 3, 2011
EPA and UDEQ will accept written comments to the pro-
posed plan during the public comment period.
Written comments should be submitted to:
Paula Schmittdiel,
U.S. Environmental Protection Agency, Region 8
1595 Wynkoop Street
Denver, Colorado 80202-1129
Mail Code: 8EPR-SR
E:mail: schmittdiel.paula@epa.gov
PUBLIC MEETING:
Monday, April 11, 2011 at the Eureka City Hall at
15 N Church St in Eureka, Utah
EPA and UDEQ will accept verbal comments at the public
meeting for the proposed plan.
For more information about the Eureka Mills Superfund
Site, see the Administrative Record at the following loca-
tions:
Eureka Mills Superfund Site Information Repository
Eureka City Hall
15 North Church Street
Eureka, UT 84628
(435)433-6915
EPA Superfund Records Center
1595 Wynkoop Street
Denver, CO 80202
(303)312-6473
UDEQ Division of Environmental
Response and Remediation
195 North 1950 West,
Salt Lake City, Utah
801-536-4100
Questions? Contact Jennifer Lane at:
303-312-6813 or lane.jennifer@epa.gov
March 2011
Proposed Plan for Eureka Mills Superfund Site, Operable Unit 4
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300.430(^(3) of the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP).
This proposed plan summarizes information that can be found
in greater detail in the Remedial Investigation report (Rl), Feasi-
bility Study (FS), the Baseline Ecological Risk Assessment
(BERA) and other documents found in Administrative Record
for this site. Relevant documents from the Administrative Re-
cord can be viewed at the Eureka Mills Superfund Site Informa-
tion Repository at Eureka City Hall, at UDEQ's office in Salt Lake
City, or at the EPA Superfund Records Center in Denver, CO.
EPA and UDEQ encourage the public to review these documents
to gain a better understanding of the site and the studies EPA
has completed on surface water, groundwater, and the environ-
ment that led to this proposed plan.
Site Background
Eureka is situated in a southwest trending valley on the west
side of the East Tintic Mountains in northeast Juab County,
about So miles southwest of Salt Lake City, Utah (Figure 1). Ele-
vations in Eureka range from 6,700 feet to 6,300 feet above sea
level. The town has a population of 766 as of the 2000 census.
Eureka is part of Utah's historic Tintic Mining District. It was
founded in 1870 upon the discovery of a high-grade mineralized
outcrop containing silver and lead. The area was extensively
mined until 1958 and has experienced sporadic mining activity
since. Mines near Eureka produced ores of silver, gold, lead,
copper, iron, zinc, and cadmium.
Scope and Role of the Action
This proposed plan is for OU4 at the site. "Operable
Units" (OU) are used to define separate activities undertaken at
the same Superfund site. OU4 includes groundwater, surface
water, and ecological risks associated with non-residential areas
in the outskirts of Eureka. Other operable units at the site (see
Figure 2) addressed human health risks of site soils and included
the following:
• OU oo - Site-Wide, including residential areas
• OU 1 - May Day - Godiva Shaft and Tunnel
• OU 2 - Bullion Beck- Gemini Mine Waste Piles
• OU 3 - Central Eureka Mining Areas (Chief Consolidated
Mining Company)
Remedial action for each of these operable units was completed
in October 2010 in accordance with the site Record of Decision
(ROD) for lead contaminated soils (2002 ROD). OU4 is the final
Figure 1 - Site Location Map
e
operable unit to be addressed at the site.
Site History and Response Actions
The State of Utah and EPA began investigating impacts of his-
toric mining activities on the environment and residential areas
of Eureka in 2000. High concentrations of lead and arsenic in
soil combined with elevated blood lead levels in children living in
Eureka led to Time Critical soil removal actions in 2001 and 2002.
Based on the findings of the Site Investigation in 2000, the site
was placed on the National Priorities List (NPL) in September
2002.
In 2002, EPA completed studies and published a ROD for lead
contaminated soils, which were found to pose an imminent and
substantial endangerment to public health. Site areas requiring
soil remediation were divided into four operable units; refer to
Figure 2 for the remediation areas and operable unit bounda-
ries. Lead is the primary soil contaminant of concern (COC) at
the site. Other soil COCs were found to be co-located with lead.
For additional detail on the 2002 ROD and studies completed in
2002, refer to the following documents in the Administrative
Record:
• Remedial Investigation Report for Operable Units 00-3 at
the Eureka Mills Site, Eureka, Utah, July 2002 (Rl). The
scope of the investigation included soils, tap water, air,
residential interior and exterior paint, and other residen-
tial indoor sources of lead contamination.
• Feasibility Study Report for Operable Units 00-3 at the
Eureka Mills Site, Eureka, Utah, September 2002 (FS).
The feasibility study evaluated a range of alternatives to
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March 2011
Proposed Plan for Eureka Mills Superfund Site, Operable Unit 4
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Figure 2 - Site Plan
March 2011
Proposed Plan for Eureka Mills Super-fund Site, Operable Unit 4
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(Continued from page 2)
address the contamination and risks found during the
remedial investigation.
• Record of Decision for Lead-Contaminated Soil, Operable
Units oo through 3 at the Eureka Mills NPL Site. Eureka,
Utah, September 2002 (ROD). The ROD documents
EPA's reason for its selection of the cleanup remedy.
Remedial Designs (a design of the selected cleanup remedy or
RD) for OUs oo through 3 were completed in 2003. Remedial
Action (construction of the cleanup remedy or RA) was initiated
in August 2003 and completed in October 2010. Components of
the RA included:
• Cleanup of approximately 700 residential and commercial
properties with lead in soil concentrations greater than
231 ppm. The cleanup generally consisted of removal of
18 inches of soil and construction of an 18-inch cap con-
sisting of vegetated soil or rock.
• Capping of 13 mine waste piles near Eureka that posed a
human health risk with an 18-inch cap of vegetated soil or
rock.
• Construction of a disposal cell (Open Cell) for contami-
nated soils that may be excavated during future con-
struction activities.
• Assisting the City of Eureka with developing an excava-
tion ordinance to control excavation activities that could
disturb contaminated materials.
• Public health actions, including information programs,
periodic blood lead testing of children, and a program for
evaluating sources of indoor lead exposure.
Potentially responsible parties (e.g., mine owners) performed
portions of the RA, including capping the May Day, Godiva, and
Chief Mine #2 mine waste piles, remediating the property re-
ferred to as Upper Eureka Gulch (see Figure 2), and providing
materials and resources for other RA tasks. Remaining RA ac-
tivities were performed by EPA under the authority of the
Superfund Program.
In 2007, EPA initiated studies of OU4, which were completed in
2010. The results of these studies are presented in the following
documents:
• Groundwater/Surface Water Remedial Investigation Re-
port. Eureka Mills Superfund Site Operable Unit 4. July
2010 (GW/SW Rl). This document describes groundwater
and surface water studies and provides conclusions on
the impacts (if any) to the groundwater and surface wa-
ter from historical mining activities.
• Baseline Ecological Risk Assessment for the Eureka Mills
Site. February 2010 (BERA). This document assesses risks
to ecological receptors including plants, invertebrates,
birds, and mammals.
• Focused Feasibility Study Report for Ecological Risk.
Eureka Mills Superfund Site Operable Unit 4. March 2011
(FFS). This document develops and evaluates cleanup
alternatives to lower the risk to bird populations.
Site Characteristics
Croundwater
Shallow groundwater at the site resides in unconsolidated allu-
vium and weathered bedrock. A deeper aquifer also exists in
lower sedimentary bedrock units. The depth to the lower aqui-
fer is between 1500 and 2000 feet below ground surface. Due
to the impracticality and cost of drilling and of pumping water
from these depths, placing drinking water wells in the deeper
aquifer is not a reasonably anticipated future use.
Groundwater flow is generally east to west, following topogra-
phy, with a directional component towards the valley bottom
of Eureka Gulch.
Numerous water wells have been installed in Eureka, most in
the early 19005 when the wells served as sources of drinking
water for residences. The wells were generally shallow and
drilled into soils overlying bedrock. In some cases, deeper wells
were drilled into upper bedrock units, all within what is consid-
ered the shallow aquifer under the site.
According to a well survey completed during the GW/SW Rl,
20 wells still exist in Eureka. None of these wells are known to
be used for drinking water as all residents are connected to the
Eureka municipal water system. The municipal system derives
water from two sources: a system of five wells located east of
Eureka, in Homansville, and a well located near Tintic Junction,
approximately 2 miles west of Eureka. Each of these sources is
hydraulically isolated from the shallow groundwater aquifer at
the site. A review of Eureka City's data from their water testing
(as required of municipal suppliers) from each source do not
have elevated concentrations of metals that would indicate
impact from historical mining.
In order to further characterize the nature and extent of possi-
ble groundwater contamination, EPA installed four monitoring
wells downgradient of mine waste piles in soils overlying bed-
rock and in some cases shallow bedrock units. The depth to the
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Proposed Plan for Eureka Mills Superfund Site, Operable Unit 4
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Figure 3—Map of Surface Water Bodies
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shallow aquifer was found to range from 5 feet to more than 60
feet depending on the location of the well. The selected loca-
tions of the monitoring wells were the most likely places where
contaminant releases to the shallow aquifer might occur from
waste material associated with historical mining. The soil mate-
rials of the shallow aquifer tend to be fairly tight and thus do
not produce much water. Consequently, one of the four moni-
toring wells installed by EPA did not produce enough water to
sample for water quality.
Groundwater samples were collected from existing private wells
identified in the well survey and from the monitoring wells. A
total of 14 wells were sampled 3 to 5 times over the course of
the investigation and analyzed for heavy metal concentrations.
The following table summarizes samples that exceeded the Fed-
eral Maximum Contaminant Level (MCL) or Action Level (AL):
Summary of Metals Detected Above MCL
in Croundwater
• Agricultural
The following characterize site surface water features:
Metal
Arsenic
Lead
Maximum
Detected
Concentration
19,7 ng/L
230 ng/L
Samples
Detected
Above MCL
1 of 56
2 of 56
MCL
10 ng/L
15 ug/L*
* This is a Federal Action Level; there is not an MCL for lead
MCLs and ALs are the highest concentrations of specific metals
allowed in drinking water. Of the 56 samples collected, one
sample had an exceedance of the arsenic MCL and the lead ac-
tion level and another sample had an exceedance of the lead
action level. These two samples were collected from different
wells on different dates. Additional sampling of these two wells
to confirm the presence of contamination did not find any ex-
ceedances of the MCL or AL for either lead or arsenic.
While the cause of the exceedances is not entirely clear, the
conclusion from the remedial investigation was that there were
no impacts from historical mining activities found in the shallow
groundwater aquifer and that no further action is recom-
mended.
Surface Water
Site surface water features are shown in Figure 3. The State of
Utah's designated uses of surface water in the Eureka Gulch
watershed include:
• Secondary recreation (activities with a low likelihood
for ingestion, such as fishing)
• Severely habitat limited waters
Chemical
Arsenic
Cadmium
Chromium
Copper
Lead
Selenium
Dissolved Metal
Concentration (|ig/L)
13.1
2.3
2.1
4.7
9
5
Utah State
Criteria (|ig/L)
100
10
100
200
100
50
Eureka Gulch. Eureka Gulch has a stream that passes through
the central part of Eureka, alongside Highway 6. Approximately
6.5 miles southwest of the site, the Eureka Gulch stream joins
with the Tanner Creek drainage. Typically the Eureka Gulch
stream carries water only after a rainstorm or during snowmelt
and is not considered to be a viable aquatic habitat or
usable for recreation.
Knightsville and Gardner Canyon Sedimentation Ponds. Man-
made sedimentation ponds are located at the base of the
Knightsville and Gardner Canyons. These ponds capture poten-
tially contaminated run-off from residual sources in the canyon
during storms and spring melt periods to prevent the recontami-
nation of remediated areas at the site. The ponds vary in size
and are lined with rip-rap. Based on observations made since
the first ponds were constructed in 2004, the ponds will rarely
contain water for more than a few days during snowmelt. Since
the ponds usually do not contain water, there is no likely human
exposure to surface water and the ponds are not expected to
support aquatic life or provide a consistent source of drinking
water for wildlife.
Knight's Spring Pond. Knight's Spring Pond is a small pond fed
by a spring and formed by a man-made embankment. It is lo-
cated adjacent to Knightsville Road and is the only permanent
water body located within the site boundaries. The pond was
measured to be 24 feet in diameter and 3.5 feet deep during the
spring of 2007. It serves as a watering source for wildlife and
domesticated sheep that utilize the surrounding land for graz-
ing. It may also serve as habitat for aquatic organisms.
Surface water samples were collected from Knight's Spring
Pond and from Eureka Gulch monitoring stations when surface
water was present. A total of 10 samples were collected. The
following table compares the highest metal concentration en-
countered and the Utah State numerical water quality standards
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for agriculture. Of the applicable State designated uses for
Eureka Gulch and Knight's Spring Pond (tributaries to Tanner
Creek), only the agricultural designated use includes numerical
standards for metals.
None of the surface water samples analyzed exceeded the ap-
plicable State of Utah surface water quality standards for met-
als. There was no evidence of recreational use of Knight's
Spring Pond.
In summary, recreational use is unlikely at the site given the lack
of large surface water areas or the existence of any surface wa-
ter for more than a few days during the year. Since none of the
sample results exceeded the State's water quality standards no
further action is recommended.
Sediment
Sediments are silts, sand, organic matter, or minerals that accu-
mulate on the bottom of a water body. The only water body
within the site that contains water for the majority of time is
Knight's Spring Pond. Ten sediment samples were collected
from Knight's Spring Pond and analyzed for heavy metals to
investigate ecological risks. The results indicate that several
metals exceed sediment screening levels for benthic inverte-
brates (animals without backbones that generally live on or
within the sediment, such as clams and worms). For more infor-
mation about concentrations of heavy metals and sediments,
refer to the BERA. Although there are some exceedances of
screening levels, the size of the pond prohibits significant use by
aquatic life, thus, there is no unacceptable riskto aquatic popu-
lation. No further action addressing sediment in the pond is
recommended.
Soils
Soils data collected throughout the life of the project was used
for assessment of ecological risk. In aggregate, approximately
1,000 samples have been collected in non-developed areas
around Eureka and analyzed for heavy metals. The results indi-
cate that soils immediately outside Eureka and on the mountain
slopes surrounding Eureka have elevated metal concentrations,
predominately lead.
Refer to the following chart for a summary of lead concentra-
tion in soil (measured in ppm):
Lead Concentrations in Soil (ppm):
Non- Developed Areas
<3.000
3.000-10.000
l > 10.000
Baseline Ecological Risk Assessment
In order to evaluate potential risk to terrestrial life forms
(plants, animals, invertebrates). EPA and UDEQ performed a
baseline ecological risk assessment or BERA. In addition to the
BERA, a site-specific risk model was used to further evaluate
risks to birds.
The study area for the BERA included the undeveloped areas
north and south of the City to the ridgelines defining the valley
in which Eureka is located, and west of the site to include a
reach of Eureka Gulch. The terrain within the study area encom-
passes a range of elevations and habitats, including sagebrush
and pinion-juniper stands, thick mountain shrublands, and
wooded areas of deciduous and mixed coniferous trees. The
area is characterized by very steep slopes that are heavily vege-
tated. These habitats provide ample forage and nesting oppor-
tunities for numerous bird and mammal species. Parts of the
site are covered by mine waste piles. Some of these piles have
been capped with clean rock material because of the risk they
pose to human health from blowing dust, surface runoff, or
direct contact.
Refer to Figure 4 for an interpretation of the habitat types pre-
sent within the study area.
Environmental and biological data collected throughout the
study area were used for characterization of ecological risks.
These data were drawn from the analysis of more than 1,000
soil, surface water, groundwater, and sediment samples; plant,
earthworm and insect tissues; and toxicity/bioaccumulation
tests on plants and earthworms.
Plants and Invertebrates
The primary exposure pathway for both plants and soil inverte-
brates (worms, insects, larvae) is direct contact with contami-
nated soil. For plants, exposure may also occur due to deposi-
tion of dust on leaf surfaces, but this pathway is of minor con-
cern compared to root exposures in surface soil and subsurface
soils and therefore was not evaluated in the BERA. Based on
evaluation of the data, the following conclusions were drawn:
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Proposed Plan for Eureka Mills Superfund Site, Operable Unit 4
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Figure 4 - Map of Ecological Habitat Types
Ecological Habitat Types
| Exposure Area/Reference Area
~\ remedial action structures
Habit at Type
^^| Maple
| | Disturbed
| | Mixed Conife
^•1 Mixed Shrub
Mountain Drainage
| | Mountain Shrub
[ Pinyon-Jumper
[::::::[ Reclaimation
I Sagebrush
(Continued from page 7)
• For plants, concentrations of metals in site soil are not
high enough to be of general concern in most areas, but
in isolated locations elevated concentrations may cause
slight toxicity to individual plant species.
• Concentrations of metals in site soil are present at
levels that may cause some reduction in soil inverte-
brate growth at some locations, but the overall sur-
vival of soil invertebrates at the site is not likely to
be adversely impacted.
Birds and Mammals
Effects on birds and mammals were evaluated using 10 different
species that differed in feeding habits and home range size. A
"home range" is the area that an animal typically uses in the
course of its daily activities. For the purposes of the BERA,
home range sizes were classified as low, medium, and large:
• Small home ranges - 2 acres or less
• Medium home ranges - greater than 2 acres but less
than 200 acres
• Large home ranges - more than 200 acres and may be
many square miles
Birds and mammals may be exposed to site related contami-
nants by four main pathways:
• Ingestion of contaminants in prey
• Incidental ingestion of surface soil while eating
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• Ingestion of contaminated water
• Incidental ingestion of sediment while drinking
Birds and mammals may also be exposed by direct contact and
inhalation exposure to airborne dusts, but these exposure path-
ways are usually considered to be minor in comparison to expo-
sures from ingestion and were not evaluated quantitatively.
Based on the BERA, which included an evaluation of the chemi-
cal data combined with expected exposures to wildlife using the
site, the following conclusions were drawn by EPA:
• Risks to most birds and mammals with large home
ranges are considered to be minimal.
• Potentially significant risks may occur for small- and
medium home range birds. These risks are due to
ingestion of lead and other metals in soil and sedi-
ment and also from the ingestion of metals in food
(primarily insect tissue) at the site.
• Ingestion of lead in soil contributes the most to the
risk.
The BERA process is a thorough evaluation of the potential risk
to ecological receptors. There are many uncertainties in these
types of assessments because limited species-specific informa-
tion is available to model specific animals. Because potentially
significant risks were identified, EPA conducted additional stud-
ies that focused on birds with small and medium home ranges.
A bird survey was conducted at the site by experts from the U.S.
Fish and Wildlife Service. Information from the bird survey was
used to develop a more realistic site-specific exposure model
that evaluated foraging habits and habitat use in the contami-
nated areas. Five representative bird species were selected for
modeling. The site-specific model was conducted on areas in
the southeast corner of the site, west of Knightsville Road
(Exposure Area 2 (EA2); See Figure 4). This area is contaminated
with lead and is predominantly covered by shrub maples, which
provides the most suitable habitat for these bird types.
The level of risk predicted by the site-specific model was lower
than that found by the initial BERA assessment, reflecting the
model's more realistic exposure scenarios. Three of the five
representative bird species were found not to be at risk from
lead exposures, but low risks (decreased egg production) to
American Robins, Brewers Sparrows, and birds with similar for-
aging habits were predicted by the model. The risks to Ameri-
can Robins, Brewers Sparrows, and similar birds were character-
ized as low in magnitude and limited to a relatively small area of
the site.
Summary of Site Risks
Human Health Risk
Groundwater was investigated through research of available
data and from several rounds of sampling and analysis. Samples
were collected from existing private wells within Eureka and
from monitoring wells installed by EPA down-gradient of mine
waste piles. Each well was sampled on multiple occasions.
Samples were analyzed for metals and compared with applica-
ble regulatory criteria and, where a regulatory criterion was not
available, to values published by EPA. While there were two
metals that exceeded the MCLs and ALs in two cases ; in neither
case did repeat sampling of the same wells result in an ex-
ceedance of the MCL or AL Based on the sampling results, EPA
concluded that groundwater does not pose a risk to human
health has recommended no further action for groundwater.
The only permanent surface water body at the site is Knight's
Spring Pond. Surface water and sediment samples were col-
lected from this pond, as well as from Eureka Gulch, which was
found to occasionally contain small puddles of water following
rain events. Based on the designated use for surface water,
results from analysis of surface water samples were compared
to State of Utah agricultural water quality standards for metals.
None of these standards was exceeded; therefore, EPA con-
cluded that there are no unacceptable risks to human health
from surface water at the site. EPA is recommending no further
action for surface water.
Sediment was assessed for risk to aquatic organisms. Sediment
data were compared to aquatic toxicity benchmarks. The com-
parison indicated a potential for risks to aquatic organisms;
however, due to the limited size of Knight's Spring pond, EPA
has concluded that insufficient habitat exists at the site to sup-
port aquatic life and would not be an unacceptable risk to
aquatic organisms. Therefore, no further action is recom-
mended.
Ecological Risk
Data collected from the sampling and analysis of soil, sediment,
surface water, insects, plants, and earthworms, as well as toxic-
ity tests, field surveys for plants and birds, and historic environ-
mental data were used to evaluate the risk from historic mining
activities to the environment in the baseline ecological risk as-
sessment.
Based on the BERA analysis, EPA concluded that there were no
significant risks to plants, mammals, or invertebrates. However,
a potential risk to small and medium home range bird species
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was identified. To further evaluate the identified risk, EPA em-
ployed a model that more rigorously evaluated species-specific
feeding behaviors and habitat preferences than the model used
in the initial BERA analysis.
Based on the additional modeling, the American Robin and birds
with similar home ranges and foraging strategies had the high-
est probability of adverse health effects (i.e., decreased egg
production), primarily from the ingestion of lead in soils. The
model estimated that 29% (+/-11%) of American Robins would be
exposed to risk above a level of concern. EPA has concluded
that while there is a risk to individual birds, there is not unac-
ceptable risk to the population. However, EPA elected to de-
velop the FFS to evaluate alternatives to lower the risk to Ameri-
can Robins and similar species. The following paragraphs de-
scribe and summarize the evaluation of alternatives developed
in the FFS.
Remedial Action Objectives
The evaluation of the data and other information gathered dur-
ing the GW/SW Rl showed no impacts to either the groundwater
or surface water. Due to the lack of evidence indicating an im-
pact (i.e., metal concentrations above the MCLs, ALs or State
water quality standards), EPA did not conduct a human health
risk assessment or a feasibility study for either groundwater or
surface water. Since the data does not indicate any impacts to
the groundwater or surface water, no further action is recom-
mended for groundwater or surface water.
Low risk was identified for American Robins and similar species
due to lead concentrations in soil within preferred habitat areas.
The Remedial Action Objective (RAO) established for OU4 to
lower ecological risk is:
Enhance sustainability of American Robin and Brewer's Sparrow
populations within site habitat areas by protecting them from the
adverse effects of lead in soil.
Summary of Remedial Alternatives
The detailed analysis of the remedial alternatives can be found
in the FFS. A summary of the remedial alternatives for OU4 eco-
logical risks are presented below.
ALTERNATIVE 1 - NO FURTHER ACTION
Under this alternative, EPA would take No Further Action at the
site to prevent ecological exposure to the soil contamination.
Cost Summary:
Estimated Total Capital Cost: $o
Estimated Total Operation and Maintenance
(O&M) Cost (30-year, present worth cost): $o
Estimated Construction Time frame: N/A
ALTERNATIVE 2 - SOIL CAPPING
This alternative would involve interrupting the exposure path-
way for birds by placing a clean soil cap consisting of 12 inches
of uncontaminated soil and 6 inches of uncontaminated topsoil
over the contaminated soil. To determine the areal extent of
remediation necessary to achieve the RAO for OU4, the site-
specific model evaluated two capping scenarios that would re-
duce risks to receptors. The model focused on Exposure Area 2
(EA2), which was found during bird surveys to have relatively
high diversity of species and the highest likely receptor use and
exposure. It is also the area on site with the highest concentra-
tions of lead in soil. The optimal scenario from the model is cap-
ping approximately nine acres of maple habitat in EA2. Because
the area to cap is relatively steep, it was estimated that approxi-
mately one-third of the area, or 3 acres, would be capped with
armor stone. This option would require removing existing vege-
tation, limited excavation, and no soil disposal.
Cost Summary:
Estimated Total Capital Cost:
Estimated Total O&M Cost
(30-year, present worth cost):
Estimated Construction Time frame:
$2,300,000
$96,000
3 months
Evaluation of Alternatives
The NCP requires EPA to use nine criteria to evaluate the differ-
ent remediation alternatives individually and in comparison in
order to select a remedy. The following table provides a sum-
mary of those nine criteria. This section of the proposed plan
also provides a brief discussion of the performance of each of
the alternatives against the nine criteria, noting how each com-
pares to the other alternatives being considered. More detailed
analysis of the alternatives can be found in the Focused Feasibil-
ity Study for OU4.
Overall Protection of the Environment
The EPA has concluded that the risk to American Robins and
similar species from the elevated lead concentrations in soil
within the preferred habitat area is acceptable. The FFS was
developed to investigate lowering the risk. The No Further Ac-
(Cont/nued on page 11)
March 2011
Proposed Plan for Eureka Mills Superfund Site, Operable Unit 4
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Evaluation Criteria for CERCLA Remedial Alternatives
Overall Protection of Human Health and the
Environment evaluates whether an alternative
eliminates, reduces, or controls threats to public health
and/or the environment through treatment,
engineering controls, or institutional controls.
Compliance with Applicable or Relevant and
Appropriate Requirements (ARARs) evaluates whether
an alternative meets Federal and State environmental
statutes, regulations, and other requirements that
pertain to the site, or whether an ARAR waiver is
justified.
Long-Term Effectiveness and Permanence considers
the ability of an alternative to maintain protection of
human health and/or the environment over time.
Reduction of Toxicity, Mobility, or Volume of
Contaminants through Treatment evaluates an
alternative's use of treatment to reduce the harmful
effects of principal contaminants, their ability to move
in the environment, and the amount of contamination
present.
Short-Term Effectiveness considers the length of time
needed to implement an alternative and the risks the
alternative poses to workers, residents, and the
environment during implementation.
Implementability considers the technical and
administrative feasibility of implementing an
alternative, including factors such as the relative
availability of goods and services.
Cost includes estimated capital and annual O&M costs
as well as present worth cost. Present worth cost is the
total cost of an alternative overtime in terms of today's
dollar value. Cost estimates are expected to be
accurate within a range of +50 to -30 percent.
State Acceptance considers whether the State agrees
with the recommendations as described in the RI/FFS
and this proposed plan.
Community Acceptance considers whether the local
community agrees with the analyses and the Preferred
Alternative. Comments received during the public
comment period for this proposed plan are an
important indicator of community acceptance.
(Continued from page w)
tion Alternative does not lower the identified risk, whereas the
Capping Alternative minimizes birds' exposure to the lead con-
taminated soil. While the No Further Action Alternative does
not take action to lower risks to birds, it does have the benefit
of not disrupting the existing habitat.
Many other species of wildlife also use the habitat that would
be destroyed during construction of the Capping Alternative. In
addition, the Capping Alternative would permanently eliminate
some of the habitat because a third of the remediation area
would be capped with armor stone due to the steep slopes.
Compliance with Applicable or Relevant and Appropriate Re-
quirements
There are no chemical, location, or action specific ARARs di-
rectly applicable to the protection of wildlife.
Long-Term Effectiveness and Permanence
The No Further Action Alternative would not lower potential
impacts to individual birds from exposure to soil contaminants.
Based on the B ERA modeling, the Capping Alternative would
provide long-term reduction of risk to birds and, with operation
and maintenance efforts, provide a permanent solution.
Reduction of Toxicity, Mobility, or Volume of Contaminants
through Treatment
None of the alternatives include treatment.
Short-Term Effectiveness
As a consequence of the Capping Alternative, habitat for the
affected species and for all wildlife would be lost in the short-
term. There is currently a mature stand of trees in the EA-2 area
and it is estimated that it would take 15 to 30 years for the habi-
tat area that is destroyed to be completely restored. In addi-
tion, the Capping Alternative would eliminate a third of the
prime maple habitat due to the steep slopes that would be
capped with rock. The No Further Action Alternative would
leave a potential for exposure to soil contaminants.
Implementability
Capping of a limited area in EA-2 would involve some construc-
tion difficulties, but other remedial measures taken at the site
have shown capping on steep slopes to be achievable. Material
for construction of the cap is not currently available locally,
which will increase difficulty and cost. Depending on vegetation
type, revegetation/habitat restoration could take from 15 to 30
years to accomplish.
No Further Action does not require implementation.
Cost
The following summarizes the capital, operation, and mainte-
nance costs (30-year) for the different alternatives. It is recog-
nized that statutory 5-year review of the project will be required
(Continued on page 12)
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Page 11
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(Continued from page 11)
under each alternative. The cost for 5-year review of OU4 is not
included.
SUMMARY OF ESTIMATED COSTS
• No Further Action Alternative
Capital Cost: $o
Operation and Maintenance Cost: $o
• Capping Alternative
Capital Cost: $2.3M
Operation and Maintenance Cost: $96,000
State Acceptance
The State of Utah supports the Preferred Alternative.
Community Acceptance
Community acceptance of the Preferred Alternative will be
evaluated after the public comment period ends and will be
described in the ROD for OU4.
Summary of the Preferred Alternative
EPA studied the impact of historical mining activities to ground-
water and surface water and based on the data collected, it is
proposing the following actions for the protection of human
health:
1. For groundwater, EPA is recommending No Further
Action be taken.
EPA's recommendation is based on the lack of evidence show-
ing any metals in the groundwater that exceed the MCLs or ALs.
2. For surface water, EPA is recommending No Further
Action be taken.
EPA's recommendation is based on the lack of evidence show-
ing any metals in the surface water that exceed the State's wa-
ter quality standards.
3. For ecological risks, EPA is recommending "No Further
Action" as the preferred alternative at OU4.
EPA's preference for the No Further Action Alternative is based
on several factors:
• the limited population of at-risk wildlife observed using
the contaminated site areas
• EPA's conclusion that population level risks were ac-
ceptable
• the difficulty and cost associated with capping and
restoring the prime maple vegetation in areas that are
currently vegetated
• the presence and use by co-existing species assumed
to use the same habitat that are not at risk
While this option does not take action to lower risks to the small
population of birds that are potentially at risk, it does have the
benefit of not disrupting the existing habitat. EPA believes that
based on the site-specific characteristics and populations using
this site, the harm of disrupting the habitat being used by many
other animals outweighs the benefit that would be gained for
the small population of American Robins and similar species.
Destruction of habitat areas that support these bird species to
remove the contamination would not enhance the sustainability
of the American Robin and Brewer's Sparrow populations and
thus would not meet the Remedial Action Objective.
Community Participation
EPA is requesting that the public comment on the recommenda-
tions for No Further Action for the groundwater, surface water
and ecological risk presented above. Formal comments on this
proposed plan can be submitted during the public comment
period or at the public meeting.
The 30-day public comment period is being held from:
Monday, April 4, 2011 through Tuesday, May 3, 2011
Please note that comments received outside of the public com-
ment period are considered informal and may not receive a re-
sponse. Comments may also be provided during the public
meeting that will be held at from 6:00 to 7:00 p.m. on:
Monday, April 11, 2011 at the Eureka City Hall at 15 N Church St in
Eureka, Utah.
EPA and the regulatory agencies will consider all formal com-
ments prior to making a final decision for OU4. All comments
and responses will be documented in the Responsiveness Sum-
mary, which will be part of the official record and published in
the Record of Decision. Copies of the Responsiveness Summary
will be mailed to anyone who submits a formal comment. In
addition, EPA will announce the decision through the local me-
dia and on the EPA website.
Interested parties may submit comments in several ways:
Mail written comments to:
Paula Schmittdiel
U.S. Environmental Protection Agency, Region 8
(Continued on page 13)
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(Continued from page 12)
1595 Wynkoop Street
Denver, Colorado 80202-1129
Mail Code: 8EPR-SR2
Fax written comments to:
Paula Schmittdiel at 303-312-7151
E-mail comments to:
Schmittdiel.Paula@epamail.epa.gov
Offer verbal comments during the public meeting on Monday,
April 11. 2011.
Points of Contact
EPA
Paula Schmittdiel, Remedial Project Manager
U.S. Environmental Protection Agency, Region 8
1595 Wynkoop Street
Denver, Colorado 80202-1129
Mail Code: 8EPR-SR
303-312-6861
Schmittdiel.Paula@epamail.epa.gov
Jennifer Lane, Community Involvement Coordinator
U.S. Environmental Protection Agency, Region 8
1595 Wynkoop Street
Denver, Colorado 80202-1129
Mail Code: 8OC
303-312-6813
lane.jennifer@epa.gov
UDEQ
Michael Storck, Project Officer
Utah Department of Environmental Quality
168 North 1950 West (Building #2) First Floor
60x144840
Salt Lake City, Utah 84114-4840
801-536-4179
mstorck@utah.gov
Dave Allison, Community Involvement
195 North 1950 West (First Floor)
60x144840
Salt Lake City, Utah 84114-4840
801-536-4117
dallison@utah.gov
List of Acronyms
AL Action Level
ARARs Applicable or Relevant and Appropriate Require-
ments
6ERA
COC
EA
EPA
FFS
6aseline Ecological Risk Assessment
CERCLA Comprehensive Environmental Response, Com-
pensation, and Liability Act
contaminant of concern
Exposure Area
Environmental Protection Agency
Focused Feasibility Study
GW/SW Rl Groundwater / Surface Water Remedial Investi-
gation Report
MCL Federal Maximum Contaminant Level
NCP National Oil and Hazardous Substances Pollution
Contingency Plan
NPL National Priorities List
O&M Estimated Total Operation and Maintenance
OU Operable Unit
ppm parts per million
RA Remedial Action
RAO Remedial Action Objective
RD Remedial Design
Rl Remedial Investigation
ROD Record of Decision
UDEQ Utah Department of Environmental Quality
March 2011
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