PB97-964023
EPA/541/R-97/189
January 1998
EPA Superfund
Record of Decision:
Oak Ridge Reservation (USDOE), OU 2
(Oak Ridge Y-12 Plant Bear Creek Valley)
Oak Ridge, TN
1/23/1997
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DOE/OR/02-1435&D2
Record of Decision
for
Bear Creek Valley Operable Unit 2
(Spoil Area 1 and SY-200 Yard)
at the Oak Ridge Y-12 Plant,
Oak Ridge, Tennessee
OOE
uffunJN
on
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DOE/OR/02-1435&D2
Record of Decision
for
Bear Creek Valley Operable Unit 2
(Spoil Area 1 and SY-200 Yard)
at the Oak Ridge Y-12 Plant,
Oak Ridge, Tennessee
Date Issued—September 1996
Prepared by
Jacobs ER Team
125 Broadway Avenue
Oak Ridge, Tennessee
under contract DE-AC05-93OR22028
Prepared for
U.S. Department of Energy
Office of Environmental Restoration and Waste Management
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PREFACE
This Record of Decision for Bear Creek Valley Operable Unit 2 (Spoil
Area 1 and SY-200 Yard) at the Oak Ridge Y-J2 Plant, Oak Ridge.
Tennessee (DOE/OR/02-1435&D2) was prepared in accordance with
requirements under the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 to document the selected
remedy. This work was performed under Work Breakdown Structure
1.4.12.1.1.02 (Activity Data Sheet 2302, "Bear Creek Valley").
Publication of the D2 version of this document will meet a Federal
Facility Agreement milestone. This document is based on information
provided in the Feasibility Study for the Y-12 Bear Creek Valley
Operable Unit 2 Spoil Area 1, SY-200 Yard, and Rust Spoil Area, Oak
Ridge, Tennessee (DOE/OR/02-1279&D2).
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ACRONYMS AND ABBREVIATIONS
ARAR
Ba
Be
bis
CERCLA
Cd
CFR
Co
Cr
DOE
EPA
FR
FS
ft
ha
Hg
in.
kg
km
L
m
MCL
Mg
mg
Mn
mrem
NCP
Ni
NPL
NTS
O&M
ORNL
ORR
OU
PAH
Pb
PCB
Ra
RI
ROD
Sb
svoc
TBC
applicable or relevant and appropriate requirement
barium
beryllium
below land surface
Comprehensive Environmental Response, Compensation, and Liability
Act of 1980
cadmium
Code of Federal Regulations
cobalt
chromium
U.S. Department of Energy
U.S. Environmental Protection Agency
Federal Register
feasibility study
foot
hectare
mercury
inch
kilogram
kilometer
liter
meter
maximum contaminant level
microgram
milligram
manganese
millirem
National Oil and Hazardous Substances Contingency Plan
nickel
National Priorities List
Nevada Test Site
operation and maintenance
Oak Ridge National Laboratory
Oak Ridge Reservation
operable unit
polyaromatic hydrocarbon
lead
polychlorinated biphenyl
radium
remedial investigation
record of decision
antimony
semivolatile organic compound
to be considered
nWH9601.6MC/CIE
111
16. 1996
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ACRONYMS AND ABBREVIATIONS (continued)
TDEC Tennessee Department of Environment and Conservation
U uranium
V vanadium
VOC volatile organic compound
yd yard
JTOOOS9601.6MC/CIE IV
September 16. 1996
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PARTI. DECLARATION
JTOM59601.6MC/OE September 16. 1996
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SITE NAME AND LOCATION
U.S. Department of Energy
Oak Ridge Y-12 Plant Bear Creek Valley Operable Unit 2
Oak Ridge Reservation
Oak Ridge, Tennessee
STATEMENT OF BASIS AND PURPOSE
This record of decision (ROD) selects the remedial action for the Oak Ridge Y-12 Plant
Bear Creek Valley Operable Unit (OU) 2 in Oak Ridge, Tennessee, in accordance with the
Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA),
as amended by the Superfund Amendments and Reauthorization Act of 1986 and, to the extent
practicable, the National Oil and Hazardous Substances Contingency Plan (NCP). This ROD
provides background information on the site, outlines the technical goals of the remedy,
summarizes the analysis of potential remediation alternatives, explains the rationale for the
selected remedy, and certifies that the remedy complies with CERCLA. Implementation of the
selected remedy will ensure that human health and the environment are protected from exposure
to contaminants at Bear Creek Valley OU 2.
The remedial action decision is based on the administrative record for the Y-12 Plant Bear
Creek Valley OU 2, including the remedial investigation (RI) (DOE 1995a), the feasibility study
(FS) (DOE 1995b), the proposed plan (DOE 1995c), and other documents contained in the
administrative record file for this site.
This document is issued by the U.S. Department of Energy (DOE) as the lead agency.
The U.S. Environmental Protection Agency (EPA) and the Tennessee Department of Environment
and Conservation (TDEC) are supportive agencies as parties of the Federal Facility Agreement
for this response action, and they concur with the selected remedy.
ASSESSMENT OF THE SITE
Releases from this site or exposure to the hazardous media would present unacceptable
risks to human health and the environment if the response action selected in this ROD is not
implemented.
rro005960l.6MC/OE 1-2 September 16. 1996
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DECLARATION STATEMENT
The primary objective of this remedial action is to mitigate risks to human health and the
environment from exposure to contaminated soil and waste. Low levels of metals, organic
compounds, and radionuclides were detected in soil at the OU 2 sites: Spoil Area 1 and the
SY-200 Yard.
The selected remedy for Spoil Area 1 and the SY-200 Yard addresses the principal threats
at the sites by maintaining the existing waste covers and implementing specific access and use
restrictions. Access and use restrictions will prevent unacceptable exposure to the contaminants.
Deed restrictions will be implemented to restrict construction that could negatively impact the
integrity of the covers at the sites and prohibit waste intrusion. Restrictions will also require
incorporation of indoor radon mitigative measures in accordance with EPA guidelines for any
future structure built on site. The site will be designated as a restricted industrial use area.
Groundwater and surface water/sediment monitoring will be deferred to the Bear Creek Valley
OU ROD scheduled for approval in Fiscal Year 1999. Major components of the selected remedy
include the following:
• physical barriers (fences, gates, and signs) to limit access to the site;
• deed restrictions to restrict construction at the sites and prohibit waste intrusion to
mitigate direct exposure; and
• periodic physical surveillance of the soil cover and other features of the site and
maintenance or repa^vas required.
STATUTORY DETERMINATIONS
The selected remedy protects human health and the environment, complies with federal
and state requirements that are legally applicable or relevant and appropriate to the remedial
action, and is cost-effective. The selected remedy provides the best balance of tradeoffs in terms
of the nine CERCLA criteria for evaluation. The risk reduction provided by treatment is not
commensurate with additional costs. Therefore, this remedy does not satisfy the statutory
preference under CERCLA 121(b) for treatment to reduce the toxicity, mobility, or volume of
contaminants. Because this remedy will not result in the removal of hazardous substances present
JTOXJ59601.6MC/CJE 1-3
16. 1996
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above health-based risk levels from the site, a 5-year review will be conducted after completion
of remedial action to ensure that the remedy continues to protect human health and the
environment.
JT00059601.6MC/CJE 1-4 Sqttmta 16. 1996
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APPROVALS
Hall, Manager
U.S. Department of Energy
Oak Ridge Operations Office
Date
Earl C. Leming, Director
U.S. Department of Energy Oversight Division
Tennessee Department of Environment and Conservation
Date
7
John Hankinson, Regional
Region IV
U.S. Environmental Protection Agency
itor
Date
rrOOQ59601.6MaCJE
1-5
September 16. 1996
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PART 2. DECISION SUMMARY
JT0005960I.6MC/OE Scpunter 16. 1996
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SITE NAME, LOCATION, AND DESCRIPTION
The DOE Oak Ridge Reservation (ORR) is in Anderson and Roane Counties near the city
of Oak Ridge in eastern Tennessee. Figure 2.1 shows the city's location, approximately 32 km
(20 miles) northwest of Knoxville, Tennessee. The reservation, 14,300 ha (35,300 acres) of
federally owned land, houses the Oak Ridge K-25 Site, the Oak Ridge National Laboratory
(ORNL), and the Y-12 Plant.
The Y-12 Plant encompasses approximately 320 ha (800 acres) and is adjacent to the
corporate center of the city of Oak Ridge. The plant occupies Bear Creek Valley between
Chestnut Ridge to the south and Pine Ridge to the north of the plant.
The Bear Creek Valley OU 2 (see Fig. 2.1) is in Bear Creek Valley near the headwaters
of Bear Creek immediately west of the Y-12 Plant's main facilities. Bear Creek Valley OU 2 is
comprised of a former construction spoil area, Spoil Area 1, and a former construction storage
yard, the SY-200 Yard.
The surface water system in the area is comprised of Bear Creek and its tributaries. Bear
Creek runs parallel to the SY-200 Yard. An intermittent stream, located on the eastern edge of
the SY-200 Yard, flows north to Bear Creek. Spoil Area 1 includes a drainage ditch on its
eastern side. Drainage Ditch A is the only surface water feature located in Spoil Area 1.
SITE HISTORY AND ENFORCEMENT ACTIVITIES
On November 21, 1989, EPA placed ORR on the National Priorities List (NPL) under
CERCLA. On January 1, 1992, a Federal Facility Agreement was implemented by DOE, EPA,
and TDEC. The agreement provides a procedural framework and schedule for evaluating,
prioritizing, and managing areas of contamination on ORR. The agreement specifies that
CERCLA procedures be followed to evaluate and remediate contamination problems. Work at
Spoil Area 1 began as a Resource Conservation and Recovery Act of 1976 facility investigation
before the site was listed on the NPL. However, further work has been conducted under
CERCLA.
Originally constructed as part of the Manhattan Project in the early 1940s, the Y-12 Plant
has developed into a highly sophisticated manufacturing and developmental engineering facility.
Manufacturing activities at the Y-12 Plant included chemical processing and engineering. In
JTO»5960!.6MC/CJE 2-2 Sqxmbcr 16. 1996
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V
u>
BEAR CREEK VALLEY OU 2
11 ffCff
BCV OU 2
Dak Ridge
Reservation
K N 0 X
TENNESSEE
NOT TO SCALE
R 0 A N E | S y
x,-»' LOU DON ss
^ /•' 'v J
JE
DOE •
Fig. 2.1
Bear Creek Valley
Operable Unit 2
Y-1? Pl«ni, Bear Creek Vifl»x OU J • Oik Ridge. Tennesse!
OOCUUENI C 1JHDO
0005-JO / ROD
DRAWING ID:
SS I?H»OWG
ORAWINO DAK:
M» J. 1996 tO
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support of these activities, disposal areas for uncontaminated fill and construction debris (Spoil
Area 1) and for the temporary, aboveground storage of equipment (the SY-200 Yard) were
established.
SPOIL AREA 1
Spoil Area 1 is west of the Y-12 Plant on Old Bear Creek Road. Various renovation,
maintenance, and construction operations at the Y-12 Plant produced construction debris, which
included concrete, asphalt, brick, brush, rock, and tile. Solid waste (spoil material) generated
during these operations was disposed of in Spoil Area 1 from 1980 to 1985. A soil cover was
placed over Spoil Area 1 in 1985.
Spoil Area 1 is a Class IV landfill, permitted by TDEC (permit number DNL-01-103-
0012) for the disposal of construction and demolition waste. No spoil material was received by
the unit for approximately 5 years after 1985. However, the volume of waste placed at the unit
had exceeded the landfill limit by 8,946 m3 (11,700 yd3). TDEC was notified in 1991 of the
overfilled condition.
SY-200 YARD
The SY-200 Yard is west of the Y-12 Plant on Old Bear Creek Road between Spoil
Area 1 and the Rust Spoil Area. From the 1950s to 1986, the SY-200 Yard was an aboveground
storage facility for machinery and miscellaneous items. No chemicals or waste materials were
stored at the site, and all containers (e.g., tanks) at the site were empty and stored for future use.
The site was surrounded by a 1.8-m (6-ft) fence with gate access. The operation divisions that
used the yard included the Y-12 Plant Assembly Division, Engineering Technology Division,
Metal Preparation Division, and the ORNL Fusion Energy Division. Items stored at the site were
segregated with respect to ownership by the various operating divisions using the yard. After the
presence of visible mercury was detected on the SY-200 Yard, a soil cover of 0.9-1.7 m (3-5 ft)
was placed at the site.
HIGHLIGHTS OF COMMUNITY PARTICIPATION
The proposed plan for the Y-12 Bear Creek Valley OU 2 (DOE 1995c) was issued in
August 1995. The proposed plan and other supporting documents for Bear Creek Valley OU 2,
such as the RI and FS are available to the public in the Administrative Record File at the DOE
Information Resource Center. DOE published a notice of availability regarding the project in The
JTDOOS9601.6MOOE 2-4 September 16. 19%
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Oak Ridger and The Knoxville News-Sentinel newspapers on October 18, 1995. The public
comment period was set from October 18 through November 17, 1995. In the notice, the public
was offered the opportunity to request a public meeting, but none was requested. Because no
public comments were received, the selected remedy has not been modified, and DOE has
determined that the actions suggested in the proposed plan are justified.
SCOPE AND ROLE OF THE SITE
Bear Creek Valley OU 2 originally included three sites (Rust Spoil Area, Spoil Area 1,-
and SY-200 Yard). The Rust Spoil Area was removed from OU 2 because it appears to
contribute to groundwater contamination. The Rust Spoil Area and underlying groundwater will
be addressed as part of the overall Bear Creek Valley OU, which includes all groundwater for
the valley.
The remaining OU 2 sites, Spoil Area 1 and SY-200 Yard, do not contribute to
groundwater contamination. The site risks are associated with direct exposure to contaminated
soil and waste. This risk is mitigated through the selected remedy. Bear Creek Valley OU will
address the remaining source units in the valley and issues related to groundwater and surface
water. Therefore, actions taken through the selected remedy for OU 2 are justified and consistent
with the strategy for addressing principal threats posed by sources in the Bear Creek Valley OU.
Spoil Area 1 is a 2-ha (5-acre) site that received construction debris from 1980 until 1985,
at which time a 0.61-m (2-ft) minimum soil cover was placed over the site.
The SY-200 Yard was used from the 1950s until 1986 to temporarily store equipment.
After the stored equipment was removed in 1986, mercury was discovered during the construction
of an environmental support facility at the site. Construction stopped and the site was covered
with 0.9-1.7 m (3-5 ft) of clean soil.
SUMMARY OF SITE CHARACTERISTICS
During the RI, soil, surface water, sediment, and groundwater were sampled and analyzed
for contamination. Most compounds were near background levels.
mOa»«>1.6MCOE 2-5 September 16. 19%
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SPOIL AREA 1
Nature and Extent of Contamination. Subsurface soil samples were taken from six soil
borings at Spoil Area 1. Soil borings were constructed through the fill material and into the
native underlying soil. Samples were not taken of the clean cover, but were taken throughout
the fill material at 1.2-m (4-ft) intervals and once in the native soil. Samples were analyzed for
volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs), inorganic
contaminants, and radiological parameters. A comparison of historical sample data indicated that
57 analytes were present above background levels. Those constituents that were not laboratory
contaminants (are not necessary nutrients) and were detected more than once include metals (Ba,
Be, Cd, Co, Hg, Cr, and Mn), SVOCs, and radionuclides (total uranium and radium). Metals
that were detected did not provide evidence of spatial trends of distribution. Most analytes were
only slightly above background. Constituents that significantly exceeded background levels are
beryllium, benzo(a)pyrene, benzo(a)anthracene, benzo(b)fluoranthene, and ^Ra. Waste disposal
records for the site were reviewed to identify a potential source of radium, but no records
concerning radium were found.
Constituents in the small, intermittent seep at Spoil Area 1 above background include Sb,
Pb, Co, V, Hg, and Ni. Mercury was the only constituent in an unfiltered sample to exceed the
maximum contaminant level (MCL). However, mercury was not detected in the filtered sample.
Three metals were detected in surface water samples. Iron and aluminum were detected,
but these metals are naturally occurring and essential nutrients. Small concentrations of antimony
were also detected. The detected contaminant concentrations were all below risk-based levels.
Groundwater at Spoil Area 1 contained acetone and tetrachloroethene, 1,2-dichloroethene,
and trichloroethene." This suite of contaminants is characteristic of the groundwater plume
emanating from the nearby S-3 site. The lack of soil contamination and the similarity of
contaminant types to other nearby contaminant plumes indicate that Spoil Area 1 is not a likely
source for the VOC groundwater contamination at this site.
Contaminant Fate and Transport. Metal contaminants such as beryllium that are
migrating from the fill material at Spoil Area 1 are being adsorbed in the underlying native soil
residuum. This process of adsorption has essentially eliminated the transport of contaminants into
groundwater. In addition, the SVOCs detected are characterized by relatively low volatility and
low solubility in water. The SVOCs are expected to be relatively immobile in the soil and to
remain partitioned in the fill and debris of the landfill.
2-6
September 16. 1996
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The presence of radium indicates that radon will be formed. The release of radon and
subsequent decay products could result in potential exposure via inhalation if a hypothetical
enclosed structure allows sufficient buildup of decay products. Therefore, the air medium
represents a migration pathway for small amounts of radon, a decay product of radium. In
general, polyaromatic hydrocarbons (PAHs) released to the soil are expected to adsorb very
strongly to the soil and are not expected to leach below the top few inches of soil. The ultimate
fate of PAHs is biodegradation and biotransformation by benthic organisms.
SY-200 YARD
Nature and Extent of Contamination. Sampling before the RI had consisted of three
sampling events: July 1986, January 1988, and January 1989. Six samples were collected in July
1986. The majority of the 59 soil borings sampled during the RI were on the eastern and western
portions of the site where historical information indicated contaminants would most likely be
present. Because historical data indicated that at least 0.9 m (3 ft) of clean fill covered the site,
sampling began at 0.9 m (3 ft) below the surface. Of the 65 analytes identified as above
background, only beryllium, mercury, Aroclor-1254, Aroclor-1260, and benzo(a)pyrene
significantly exceeded background levels.
Mercury was detected to a concentration of 816 mg/kg, and free mercury was seen in
some of the borings. Delineation of mercury contamination is difficult because the analysis of
samples containing visible mercury did not always indicate mercury. The reason visible mercury
may not result in high analytical detections is that the mercury binds together to form visible
nuggets. However, if those nuggets are not selected for analysis during sampling or when the
analyzer selects a portion of the sample for analysis, the analytical results will hot show visible
mercury. However, mercury was primarily found above risk-based levels in the eastern and
western portions of the site at 0.9-3.3 m (3-11 ft) bis.
Analytes detected in water samples taken from wet weather conveyances are compared to
groundwater MCLs for screening purposes only and not to compare the water samples to any
ARAR. Sampling indicated that aluminum and iron exceeded MCLs. Aluminum and iron are
thought to be naturally occurring. The maximum total lead concentration of 5.7 /tg/L is below
the TDEC action limit of 15 /ig/L, which is a guidance level used for groundwater usable for
drinking water.
The RI included installation of shallow wells because the SY-200 Yard had no existing
wells. During drilling, a perched water table was encountered in the fill material at 4-5-m
(15-20-ft) depths. This perched water table was sampled and analyzed. No groundwater
JT00059601.6MOCJE 2-7
16, 2996
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contamination was detected in wells in the SY-200 Yard. This lack of contamination is expected
because the contaminants in the soil [mercury and polychlorinated biphenyls (PCBs)] are fairly
insoluble and do not readily migrate into the underlying groundwater.
Contaminant Fate and Transport. The fate and transport of metals, such as beryllium,
and SVOCs, such as benzo(a)pyrene, would be as described for Spoil Area 1. The data do not
suggest that migration to groundwater has occurred. Mercury, PAHs, and PCBs have similar
transport characteristics. Migration of contaminants from SY-200 Yard is not expected because
of the low solubility of mercury and PCBs, the primary contaminants present. Future erosion
of the soil cover and subsequent erosion of contaminants into Bear Creek is possible. Mercury-
is volatile and could be released to the air; however, migration of mercury through air is likely
to be minimal.
The low water solubility of PCBs, their high octanol/water partition coefficient, and the
strong adsorption to soils indicate that leaching should not occur in soil under most conditions.
PCBs (represented at the SY-200 Yard by Aroclor-1254 and -1260) do not degrade in soil by any
known chemical processes, degrade very slowly by biodegradation processes, and are largely
comprised of higher chlorinated species that are resistant to biodegradation. Data support the
limited migration potential of PCBs in that none were detected in the groundwater.
SUMMARY OF SITE RISKS
The risk assessment for the Bear Creek Valley OU 2 shows that soil poses a potential
human health risk. Risk exposure for soil was calculated according to the baseline scenario,
which assumes that all controls, fencing, and waste covers are not barriers to receptor exposure.
Two exposure scenarios, an industrial worker scenario and a residential scenario, were evaluated
in the risk assessment. Because of the location and current and projected future land use of OU
2, an industrial worker was evaluated as the most reasonable and most likely future receptor.
In addition, a conservative estimate of risk to residential receptors was evaluated.
The exposure pathways evaluated for the land use scenarios for each OU 2 site included
incidental ingestion of soil, inhalation of dust and VOCs, dermal contact with soil, and external
exposure to radionuclides in the soil. Ingestion of homegrown vegetables and fruits was also
evaluated for the residential scenario.
The ecological risk assessment is based on Risk Assessment Guidance for Superfund,
Volume II, Environmental Evaluation Manual (EPA 1989). This assessment determines if and
JTW)05960I.6MC/aE 2-8 Sepmnber 16. 19%
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where adverse ecological effects to receptors other than humans and domestic animals occur as
a result of exposure to contaminants from Bear Creek Valley OU 2 and whether remediation is
needed.
Because of the semiquantitative nature of the characterization of biota and habitats at risk,
the assessment of potential impacts to wildlife and vegetation from exposure to contaminants is
based largely on lexicological effects reported in the literature for the contaminants of potential
concern. Field measurements of contaminant concentrations and published toxicity data for
terrestrial organisms allow for a quantitative estimate of risk using the ratio or quotient method.
Because aquatic exposures in the source units are very limited, emphasis is given to terrestrial-
organisms at the Bear Creek Valley OU 2 units. Risks to aquatic communities will be evaluated
as part of the RI for the overall Bear Creek Valley OU.
SPOIL AREA 1
Human Health Risks. Only exposure to radium exceeded EPA's threshold risk of
1 x 10"4 for both exposure scenarios; however. Be, ^Ra, 238U, and benzo(a)pyrene exceeded an
excess cancer risk of 1 x 10* for the residential scenario. The total risk for the industrial
scenario is estimated at 4.8 x 10* (2.0 x 10* without radium). The total risk for the residential
scenario is estimated at 1.1 x 10~3 (1.0 x 10~s without radium). The garden scenario (not
included in the total risk summary) contributed a risk of 4.8 x 10~* and a hazard index of 20,
where a hazard index greater than 1 implies the potential of inducing toxicological effects. The
elevated risk is primarily from radionuclides such as uranium, and the elevated hazard index is
primarily from manganese. Manganese is thought to be naturally occurring and not related to
site activities. $
Environmental Risks. Spoil Area 1 is a grass-covered, terraced hillside bordered at the
top by a forest. A small seep exists at the base of Spoil Area 1 beside a road. The primary
exposure environment is the grassed soil surface and the underlying soil. Therefore, the
contaminant sources examined include surface and subsurface soil. Contaminants of potential
ecological concern at Spoil Area 1 include inorganics and organics. These contaminants were
then evaluated against a set of screening benchmarks to determine the contaminants of ecological
concern. After this secondary screening, manganese was found to be a contaminant of ecological
concern for small mammals at Spoil Area 1.
2-9
September 16. 1996
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SY-200 YARD
Human Health Risks. The contaminant-specific risks are at or less than 5 x W6 with
a total risk of 2.9 x 10"* for the industrial scenario and 2 x 10"3 for the residential scenario (not
including the garden scenario). Although no contaminants exceeded a hazard quotient of 1
(including mercury) on a sitewide basis, it was possible to identify limited areas contaminated
with mercury. A risk assessment on those areas showed a hazard index of 1.6, slightly above
EPA's threshold value of 1, for the residential scenario due to mercury. The garden scenario
shows a risk of 2 x 103, due primarily to 238U, and a hazard index of 70, due primarily to
mercury and manganese.
Environmental Risks. The SY-200 Yard is a denuded and graded lot surrounded on three
sides by open industrial areas and on the fourth side by a vegetated bank descending to Bear
Creek. This sloping side of the lot is the primary exposure environment for ecological receptors
at the SY-200 Yard, mostly from vegetation growing on and animals burrowing into contaminated
soil. Because the surface soil is not contaminated, airborne dust is not an exposure pathway.
Inorganic and organic compounds were considered as contaminants of potential concern.
However, after the secondary screening against toxicity benchmarks, the only soil contaminants
of concern at the SY-200 Yard were mercury for plants and manganese for small mammals.
DESCRIPTION OF ALTERNATIVES
RISK MANAGEMENT
In the FS, contaminants of concern targeted for remediation for Spoil Area 1 and SY-200
are ^Ra and mercury, respectively. Other contaminants with an excess cancer risk between
1 x 10^ and 1 x 10"4 for the site include beryllium and benzo(a)pyrene at Spoil Area 1 and
benzo(a)pyrene, dibenzo(a,h)anthracene, and PCBs at SY-200 Yard. These contaminants are not
targeted for remediation for several reasons. First PAHs, benzo(a)pyrene and
dibenzo(a,h)anthracene, are found at very low levels throughout the Y-12 Plant and are not a
significant health risk as shown in the baseline risk assessment. Remedial actions to control the
targeted contaminants would partially address the PAHs and PCBs. Likewise, beryllium
concentrations were higher than background levels but are considered attributable to native soils
and not to the fill material at Spoil Area 1. PCBs detected during sampling are buried beneath
several feet of clean soil, reducing the risk by several orders of magnitude.
JT00059601.6MC/CJE 2-10 September 16. 1996
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DEVELOPED ALTERNATIVES
The following alternatives were evaluated in the Bear Creek'Valley OU 2 FS. In the FS,
four alternatives were developed for Spoil Area 1, and five alternatives were developed for
SY-200 Yard. The first four alternatives are very similar for both sites and are combined in the
discussion below to avoid repetition. Alternative 2 is the selected remedy for both Spoil Area 1
and the SY-200 Yard and is discussed in more detail in the "Selected Remedy" section.
ALTERNATIVE 1—NO ACTION
The no action alternative would involve no remedial actions or restrictions to reduce the
potential for exposure. Current controls and restrictions would no longer apply. DOE is
required by NCP to include this alternative in the RI/FS selection process for comparison with
other alternatives. The no action alternative can be selected if the assessment of risk in the RI
shows no potential threat to human health or the environment or if active remediation is more
harmful to human health and the environment than no action.
ALTERNATIVE 2—MAINTAIN EXISTING COVER AND INSTITUTIONAL CONTROLS
The primary intent of Alternative 2 is to maintain the existing soil cover for both sites
while monitoring site conditions over time. Institutional controls, including physical barriers and
deed restrictions, would be implemented to allow restricted industrial land use. Deed restrictions
will be implemented to restrict construction that could negatively impact the integrity of the
covers at the sites and prohibit waste intrusion. Restriction will also require incorporation of
indoor radon mitigative measures in accordance with EPA guidelines for any structure built on
site. Specific monitoring would be deferred until the Bear Creek Valley ROD (scheduled for
approval in Fiscal Year 1999) is implemented. This monitoring plan will address all media,
contaminants, and contaminant migration pathways significant to the watershed. Physical
surveillance of the soil covers and other features of the site would be performed periodically, and
maintenance or repair would be performed as required.
ALTERNATIVE 3—CAPPING, INSTITUTIONAL CONTROLS, AND MONITORING
Alternative 3 includes the installation of clay caps over both waste areas and the collection
of an intermittent seep at Spoil Area 1. A clay cap would provide a physical barrier between the
buried waste and potential human and ecological receptors. For this alternative, no waste
material would be removed. Institutional controls and monitoring would be implemented as
discussed for Alternative 2.
JTOOQ59601.6MC/OE 2-11 September 16. 1996
i
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For Spoil Area 1, a seep water collection system would be installed to minimize the
buildup of shallow subsurface water beneath the cap. The collection system would consist of
subsurface drains placed "beneath the new clay cap as required. Collected water would be treated
at a nearby water treatment facility.
ALTERNATIVE 4—SOIL REMOVAL AND DISPOSAL
Alternative 4 would achieve final remediation for both sites through removal of the
contaminated soil and debris. Excavated waste would be disposed of at an appropriate disposal
facility. Once the groundwater action is complete (under another OU), this alternative would.
allow unrestricted land use at both sites.
For Spoil Area 1, approximately 25,000 m3 (33,000 yd3) of soil and debris would be
excavated and disposed of at a new landfill cell at the Y-12 Plant. The new landfill cell would
be an addition to an existing landfill. For the SY-200 Yard, approximately 5,700 m3 (7,500 yd3)
of waste would be removed and disposed of at the Nevada Test Site (NTS).
Any uncontaminated, excavated material would be stockpiled and used as backfill in the
excavated areas. Sampling during remediation would provide for removal of all materials
contaminated above EPA-accepted cleanup levels. The remediated areas would be backfilled with
clean soil and revegetated after waste removal activities cease.
The major differences between actions for Alternative 4 at the two sites are the target
contaminants ^Ra at Spoil Area 1 and mercury at SY-200 Yard), the volume of contamination
(much greater at Spoil Area 1), and the disposal locations.
ALTERNATIVE 5—MERCURY-CONTAMINATED SOIL REMOVAL, TREATMENT,
AND REPLACEMENT
This alternative applies only to the SY-200 Yard. Mercury-contaminated soil would be
removed from the SY-200 Yard, processed in a temporary, on-site treatment facility, and returned
to the excavated areas. After treatment, no institutional controls would be needed, and the site
could be released for unrestricted use.
The most likely treatment process would be mercury-roasting, which uses beat to remove
mercury from excavated soil that has been preprocessed to reduce particle size. Treated soil
would be cooled by a water spray and placed on the site. Treatment residuals would consist of
nO»59«01.6MOCJE 2-12
Scptcnibci 16, 1996
-------
small volumes of mercury-contaminated solids, sludges, and organic liquids. These residuals
would be disposed of at existing Y-12 Plant facilities or at a commercial disposal facility.
After completing soil treatment, the treatment facility would be dismantled and removed,
and the site would be revegetated.
SUMMARY OF COMPARATIVE ANALYSIS OF
ALTERNATIVES
CERCLA requires evaluation of nine criteria for comparing the expected performance of
remedial actions. The nine criteria are identified below, and the remedial alternatives have been
evaluated on the basis of these criteria.
1. Overall Protection of Human Health and the Environment
This criterion addresses an alternative's ability to provide adequate long- and short-
term protection of human health and the environment. Alternative 1 would be the
least protective in the long term. Alternatives 2 and 3 provide equal amounts of short-
term protection for the community and workers and of long-term protectiveness,
although Alternative 3 provides the added reliability of an engineered cap.
Alternatives 4 and 5 would provide the greatest long-term protection while increasing
short-term risk to the community and workers.
Alternative 1, no action, would not protect human health because risks from exposure
to contaminants at the site currently exceed acceptable levels. There would be the
potential for increased harm to the environment, if no action were taken.
Alternative 2 would protect humans from exposure to the materials by restricting
access to the waste with institutional controls and protect the environment by
maintaining the existing covers. Alternative 3 would also protect human health with
institutional controls and the environment through the use of containment, with the
added reliability of an engineered cap over the sites. Additionally, collecting seep
water from Spoil Area 1 may limit future off-site migration of contaminants, although
the existing seep is currently not posing an environmental risk. Alternative 4 would
protect human health and the environment by removing the contaminated material and
disposing of it elsewhere. However, short-term risks to communities along the
transportation route would be slightly higher because of the potential for truck
accidents. Alternative 5 would protect human health by removing the mercury from
m>005%01.6MC/CrE 2-13 September 16. 1996
-------
the soil through roasting, a treatment technology. Likewise, the final degree of
protection would be comparable to the other action alternatives, but with enhanced
reliability.
During remediation, all action alternatives would protect the community and workers
through the use of engineered and institutional controls. Short-term risks to the
community (not including transportation) and to nonremediation workers would be
approximately equal and within acceptable limits for all four action alternatives. Air
emission controls on the roaster for Alternative 5 would limit the release of mercury
to the atmosphere.
2. Compliance with ARARs
This criterion addresses an alternative's ability to meet ARARs of all environmental
federal and state statutes and regulations.
Alternatives 2 through 5 would comply with ARARs. No waivers are anticipated for
any of the alternatives. The FS presents a comprehensive list of potential ARARs for
all alternatives. A summary of ARARs for Alternative 2, the selected remedy, is
presented in Table 2.1 and is discussed in the "Statutory Determinations" section.
3. Long-Term Effectiveness and Permanence
Long-term effectiveness and permanence refers to the magnitude of expected residual
risk and the ability of a remedy to maintain reliable protection of human health and
the environment over time, once cleanup goals have been met.
Alternative 1 would be the least effective in the long term because of the potential for
erosion of the soil cover and subsequent waste migration off site. Alternatives 2 and
3 would be equally effective and permanent. The reliability of both a soil cover
(Alternative 2) or a clay cap (Alternative 3) depends on the degree of maintenance
received. Alternative 4 would be slightly more effective because stricter controls are
placed on disposal areas, on and off site, than on industrial areas. Alternative 5 would
be the most permanent for the SY-200 Yard because soil would be treated and mercury
would be removed permanently from the site.
Long-term environmental effects are comparable among the alternatives. The site does
not contain unique habitats. To some degree, irretrievable commitment of resources
JTOOQS960I.6MC/CIE 2-14 Scpranbcr 16. 1996
-------
Table 2.1. ARARs/TBC guidance for (he selected remedy for Spoil Area 1 and SY-200 Yard,
Dear Creek Valley Operable Unit 2, Oak Ridge Y-12 Plant, Oak Ridge, Tennessee
Chemical-specific ARARs
Control of radionuclide air
emissions
Protection of the public
Releases to the atmosphere must not exceed the NESHAP of Emissions of radionuclides to 40 CFR 61.92
10 mrem/year
The public must not receive an EDE greater than 100
mrem/year
e»
All releases of radioactive material must be ALARA
ambient air from DOE
facilities • applicable to
ertvssions at Spoil Area 1
Releases of radioactive
material from all DOE
activities - TBC for any
releases at Spoil Area 1
DOE Order 5400.5
Chapter II.la
DOE Order 5400.5
Chapter IV.2c
Location-specific ARARs—None
to
Action-specific ARARs
Maintain institutional controls
Maintain active controls including fences, warning signs,
and restrictions on land use
Maintain/implement the following institutional controls as
necessary: land and water use restrictions, well-drilling
prohibitions, building permits, and well use advisories and
deed notices
Maintain/implement institutional controls for all areas where
containment is a remedial action; such controls include, at a
minimum, deed restrictions for sale and use of property, and
securing the area to prevent human contact with hazardous
substances
Long-term management of
residual radioactive material
above guidance levels - TBC
for Spoil Area 1
Long-term management of
residual contamination at a
CERCLA site • TBC for
Spoil Area 1 and SY-200
Yard
Containment and long-term
management of residual
contamination at an inactive
hazardous substance site -
applicable for Spoil Area 1
and SY-200 Yard
DOE Order 5400.5
Chapter IV.6c
40 CFR 300.430(e)(3)(ii);
55 FR 3706
TDEC I200-l-l3-.08(3)(a)4.(iv)
-------
Table 2.1. (continued)
•^IFXVUti^V* ^ff^jM
Pftrtqu&ttM •.;--
Citation
Closure with waste in place
K)
General performance standard
Operator of a Class II or IV solid waste disposal facility
must close the facility in a manner (hat:
• minimizes the need for further maintenance and
• controls, minimizes, or eliminates, to the extent
necessary to prevent threats to public health and
the environment, postclosure escape of solid waste,
solid waste constituents, leachate, contaminated
rainfall, or waste decomposition products to the
ground or surface waters to the atmosphere
Operator of a Class II or IV solid waste disposal facility
must not:
• contaminate an underground drinking water source
or
• significantly limit (he present or future uses of
groundwater underlying the area
Closure of a permitted Class
II or IV solid waste disposal
facility-applicable for SA-1;
relevant and appropriate
for SY-200 Yard
TDEC 1200-I-7-.04(8)(a)
TDEC 1200-l-7-.04(7)(a)(l)(i)
TDEC 1200-l-7-.04(7)(a)(l)(ii)
AJLARA - is low as reasonably achievable
ARAR - applicable or relevant ind appropriate requirement
CERCLA - Comprehensive Environmental Response, Compensation, and
Liability Act of 1980
CFR - Code of Federal Regulations
DOE • U.S. Department of Energy
EDB - effective dose equivalent
FR • Federal Register
mrem - millirem
NESHAP - National Emission Standards for Hazardous Air
Pollutants
TBC « (o be considered
TDEC « Tennessee Department of Environment and
Conservation
-------
would result from implementation of any of the alternatives, except the no action
alternative. Alternative 4 would result in the permanent commitment of space at both
disposal sites. Alternatives 4 and 5 would use fuel and other nonrenewable energy
sources during remediation and a small volume of treatment residuals would require
disposal. Alternatives 2 and 3 would limit use of the sites because waste would
remain in place. Alternative 3 would use clean clay for the clay caps as well as some
fuel. Alternative 2 would use small amounts of fertilizer and fuel during maintenance
actions.
4. Reduction of Contaminant Toxicity, Mobility, or Volume Through Treatment
Alternatives 3 and 5 are the only alternatives that include treatment. Alternative 5
would provide the greatest reduction in toxicity, mobility, and volume of
contaminants.
Alternatives 2 and 4 do not include any treatment; therefore, there would be no
reduction of toxicity, mobility, or volume as a result of treatment. Alternative 3
would collect and treat water from the intermittent seep. Treatment of the water
would slightly reduce the volume of contamination through metals and radionuclide
precipitation or through carbon adsorption. However, the actual reduction in toxicity,
mobility, or volume from treatment would be minimal compared to the volume of
contaminated soil at Spoil Area 1.
Alternative 5 would remediate by treatment. Roasting mercury-contaminated soil
would result in a volume reduction of contaminated material. The mercury would be
recovered in a concentrated residual or transferred onto carbon or other material used
in the collection system. Although mercury would be removed from the environment,
the benefit would be small because the mercury present (elemental) is in its least toxic
and least mobile form.
5. Short-Term Effectiveness and Environmental Impacts
This criterion considers impacts to the community, on-site workers, and the
environment during construction and implementation until protection is achieved. The
actions included in Alternative 4 would have the greatest impact on the community and
workers. Alternative 5 would also impact workers. Alternatives 1, 2, and 3 would
not disturb any waste and therefore would impact workers the least. Alternatives 3,
JTOOOS960I.6MC/OE 2-17 5^.~»t~ 16. 1996
-------
4, and 5 would impact the environment and displace or destroy inhabitant species.
Alternative 2 would have almost no effect on human health or the environment, either
in the short of long term.
Alternative 1 would not involve any action; therefore, there would be no increase in
short-term risks and no short-term environmental effects. The action alternatives
would be approximately equally protective of the local community during
implementation. Through the use of institutional controls, access to the work site
would be controlled. Alternative 2 would have virtually no short-term environmental
impact. Alternative 3 would likely increase the sediment loading in Bear Creek during-
placement of the cap. Alternatives 4 and 5 have the greatest environmental impacts
because the waste would be disturbed and contaminants could migrate during
construction. Transportation of excavated material in Alternative 4 could increase the
risk to workers (on-site disposal for Spoil Area 1) or the community (off-site disposal
for SY-200 Yard) because of the increase in risk from potential truck accidents.
Alternative 2 would require no time to implement. Alternatives 3 (for both sites) and
5 could be implemented in 4-6 months. Alternative 4 would take 3 years to
implement for Spoil Area 1 and 4 months for the SY-200 Yard after resolution of
administrative concerns, such as possible litigation and authorization to transport and
dispose of waste from ORR.
6. Implementability
Implementability is the technical and administrative feasibility of a remedy, including
the availability of materials and services needed to implement the chosen solution.
Although mere would be no insurmountable issues for any of the alternatives.
Alternatives 4 and 5 would be the most difficult to implement because of site
conditions, transportation restrictions, and administrative obstacles. Alternatives 1,
2, and 3 would be easier to implement because waste would not be disturbed.
There would be significant administrative issues concerning Alternative 4 for the
SY-200 yard. NTS does not have a contract in place to accept waste from ORR. It
is uncertain if the states between Tennessee and Nevada would allow the material to
be transported and if the state of Nevada would allow waste to be admitted into the
state. The security requirements in the area of the rail-loading platform at the Y-12
Plant would require considerable planning and may slow remediation if access to
workers is denied or shipments are inspected. Excavation and off-site disposal are
nTXXWKOl.SMC/CJE 2-18 September 16, 1996
-------
technically feasible. However, any excavation would be difficult due to the presence
of buried piles at the SY-200 Yard and the difficulty in sampling and analyzing for
mercury in soils. The need to site a new construction debris landfill adds to the
administrative difficulty of Alternative 4 for Spoil Area 1. The difference in
administrative feasibility between Alternative 4 and the others is the most significant
difference under CERCLA criteria.
Full-scale experience in roasting mercury-contaminated soils (Alternative 5) is limited.
Uncertainties regarding the achievable, site-specific soil cleanup levels, the collection
of air emissions, and the characterization of the waste residual may be reduced by-
treatability studies. Roasting is considered innovative, but implementable, because
vendors exist that could provide and operate the system.
7. Cost
Cost estimates were prepared for each remedial alternative. The estimates are based
on feasibility level scoping and are intended to aid in making alternative evaluations.
The estimate is divided into capital cost and operation and maintenance (O&M) cost.
All estimates have been escalated using DOE-approved escalation rates and a schedule
for the various activities based on similar project experience. O&M cost includes
routine surveillance, maintenance, and monitoring (if required by the alternative) for
approximately 30 years. Monitoring would support the required CERCLA 5-year
reviews.
Of the action alternatives, Alternative 4 costs the most to implement, based on present
worth cost (see Table 2.2). Alternative 5 for the SY-200 Yard has similar costs to
Alternative 4. The cost for implementing Alternative 3 is an order of magnitude less
' than Alternative 4. Alternative 2 is the least costly of the action alternatives and is
significantly less than Alternative 3.
8. TDEC Acceptance
1
i State acceptance evaluates whether the state agrees with, opposes, or has no comment
• on the preferred alternative. The state of Tennessee concurs with the selected remedy.
t
\
nTO05960l.6MOCIE 2-19 September 16. 1996
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Table 2.2. Present-worth cost (based on a 30-year present value) for remedial alternatives Tor Bear
Creek Valley Operable Unit 2, Y-12 Plant, Oak Ridge, Tennessee
Alternative
Present-worth cost <$}
• Alternative 1
• Alternative 2
— Spoil Area 1
- SY-200 Yard
• Alternative 3
— Spoil Area 1
- SY-200 Yard
• Alternative 4
— Spoil Area 1
- SY-200 Yard
• Alternative 5
— SY-200 Yard
No cost
236,000
234,000
3,400,000
1,200,000
36,000,000
12,000,000
11,000,000
9. Community Acceptance
Community acceptance addresses the issues and concerns the public may have
regarding each of the alternatives. The proposed plan presented Alternative 2 as the
DOE, EPA, and T®EG preferred alternative. The "Responsiveness Summary" in
Part 3 indicates that no comments were submitted during the public comment period.
SELECTED REMEDY
DOE, EPA, and TDEC agree that Alternative 2, the preferred alternative as presented in
the proposed plan, is the most appropriate remedy for Spoil Area 1 and the SY-200 Yard in Bear
Creek Valley OU 2. This alternative provides the best balance of trade-offs with respect to the
CERCLA evaluation criteria. Alternative 2 will allow the proposed future land use of the site
to remain consistent with the current use. Restricted industrial land use for OU 2 is appropriate
because the land west of OU 2 is designated for disposal and the land east is assigned restricted
industrial use. Institutional controls must be maintained indefinitely. The RI risk assessment
JTOXI59601.6MC/OE
2-20
September 16. 1996
-------
indicates a current risk to ecological receptors and the potential for future risk to human and
ecological receptors. The selected remedy addresses the risk with waste cover maintenance and
institutional controls.
This alternative will protect human health and the environment without exposure risk to
remediation workers from waste excavation and handling as in Alternatives 4 and 5. Alternative
2 complies with ARARs. This action will not satisfy the statutory preference for remedial actions
that use treatment to reduce toxicity, mobility, and volume. Although this alternative provides
a lesser degree of long-term effectiveness and permanence, it is the only alternative that does not
negatively impact the environment during implementation. Because Alternative 2 does not-
require disposal, on site or off site, it is significantly more administratively implementable than
Alternatives 4 and 5. The effectiveness and implementability of Alternatives 2 and 3 are
relatively the same; however. Alternative 2 is, by far, the least costly to implement.
Implementation of the selected remedy at Spoil Area 1 is estimated to have a capital cost
of about $5,000. O&M costs are estimated for 30 years at about $470,000. Based on a 30-year
present value, the present-worth cost for Spoil Area 1 is estimated to be $236,000. The
implementation of the selected remedy at the SY-200 Yard is estimated to have a capital cost of
about $18,000 with 30-year O&M costs estimated at about $540,000. Based on a 30-year present
value, the present-worth cost for the SY-200 Yard is estimated to be $234,000.
STATUTORY DETERMINATIONS
Section 121 of CERCLA establishes several statutory requirements and preferences,
including protection of human health and the environment and compliance with ARARs.
Statutory requirements also specify that, when complete, the selected remedy must be
cost-effective. It must use permanent solutions and innovative treatment technologies or resource
recovery technologies to the maximum extent practicable. Finally, the statute includes a
preference for remedies that employ treatment that permanently and significantly reduce the
toxicity, mobility, or volume of hazardous substances as their principal element.
There will be no reduction in toxiciry, mobility, or volume of contaminants through
implementation of the selected remedy because it does not include treatment.
The selected remedy will protect human health by minimiyjng direct human contact with
soil contaminants. This action will result in a decrease in cumulative risk, likely equal to or
' below the 1 x 10"6 threshold criterion. Risk reduction will be accomplished by periodic
i maintenance of the existing soil cover and implementation of institutional controls that would
2-21
ie. 19%
-------
limit access and construction and thereby eliminate the exposure pathways (primarily external
exposure and inhalation of ^Ra). There is no current or significant potential future human health
or environmental risk from the seep.
Maintenance of the soil covers will provide a barrier against direct human contact with
the buried materials. Institutional controls, such as erecting and maintaining access controls, will
serve to prevent unauthorized access to the site, thus limiting the exposure frequency for future
industrial workers. Deed restrictions will be placed on the site to preclude future residential and
farming use of the areas. Deed restrictions will restrict construction and prohibit waste intrusion.
Restrictions will also require the incorporation of indoor radon mitigative measures in accordance-
with EPA guidelines for any future structure built on site.
The monitoring program to be implemented under the Bear Creek Valley OU ROD will
be designed to evaluate migration of contaminants through groundwater and surface water. Any
unacceptable contaminant migration in the watershed, based on valley-wide cleanup goals, will
be identified and addressed during CERCLA 5-year reviews.
The selected remedy will meet or exceed all ARARs; no waivers are requested. ARARs
are listed in Table 2.1 and discussed here.
Chemical-specific requirements set health- or risk-based concentration limits or discharge
limitations in various environmental media or indicate a safe level of discharge to be considered
(TBC) during remedial actions.
Subpart H of 40 Code of Federal Regulations (CFR) 61 addresses atmospheric
radionuclide emissions from DOE facilities and is applicable to any airborne radionuclide
emissions at Spoil Area 1. EPA has issued a final National Emission Standard for Hazardous Air
Pollutants rule [54 Federal Register (FR) 51654, December 15, 1989] that limits emissions of
radionuclides to the ambient air from DOE facilities to amounts that would not cause any member
of the public to receive an effective dose equivalent of 10 mrem/year (40 CFR 61.92).
DOE Orders are not promulgated regulations and thus are not considered to be ARARs.
They are, however, required at DOE facilities. The radiation exposure limits for the public
defined in DOE Order 5400.5, "Radiation Protection of the Public and the Environment,"
(February 8,1990) are an effective dose equivalent of 100 mrem/year from all exposure pathways
and all DOE sources of radiation. The overriding principle of the DOE Order is that all releases
of radioactive material shall be "as low as reasonable achievable." These requirements are TBC
guidance for Spoil Area 1.
JT0005960I.6MC/OE 2-22
|6, 1996
-------
Performance, design, or other action-specific requirements set controls or restrictions on
particular kinds of activities related to the management of hazardous waste (52 FR 32496).
Institutional controls will be implemented to limit access, and exposure. There are no federal
regulatory requirements specifying institutional controls for CERCLA units. However, the NCP
at 40 CFR 300.430(e)(3)(ii) suggests consideration of one or more alternatives that involve little
or no treatment, but provide protection of human health and the environment through the use of
institutional controls. The preamble to the NCP provides samples of institutional controls, which
include land and water use restrictions, well-drilling prohibitions, building permits, and well use,
including land and water use advisories and deed notices (55 FR 3706). In addition, DOE Order
5400.5, Chapter IV, requires administrative (institutional) controls for long-term management in-
areas containing residual radioactivity above guidance levels. The active controls specified in the
Order as well as the NCP may be considered TBC guidance and include land restrictions, fences,
and warning sijns.
Chapter 1200-l-13-.08(3)(a)4.(iv) of TDEC's final rule, "Inactive Hazardous Substance
Site Remedial Action Program," effective February 19, 1994, requires institutional controls
whenever a remedial action does not address concentrations of hazardous materials that pose or
may pose an unreasonable threat to public health, safety, or the environment or for all areas
where containment is a remedial action. The rule stipulates that controls shall include, at a
minimum, deed restrictions for sale and use of property and securing the area to prevent human
contact with hazardous substances that pose or may pose a threat to human health or safety and
would be legally applicable for this alternative.
Chapter 1200-l-7-.04(8) of the Rules of the TDEC lists closure and postclosure standards
for Class IV solid waste disposal facilities, including final cover and grading requirements,
precipitation run-on/runoff controls, and groundwater monitoring requirements. A compacted
soil cover of 0.8 m (30 in.) [0.5-m (18-in.) low permeability layer and 0.3 m (12-in.) protective
layer] is required [TDEC 1200-l-7-.04(8)(c)(3)(ii)]. However, if the site-specific closure plan
meets the general performance standards of TDEC 1200-l-7-.04(8)(a), the TDEC Office of Solid
Waste Management can approve it, allowing alternate closure requirements than those listed in
TDEC 1200-l-7-.04(8)(c) (Pugh 1993). After waste disposition ceased in 1985, SA-1 was closed
with a 0.6-m (2-ft) minimum vegetative soil cover which is now shown, through the CERCLA
risk assessment, to be protective of human health and the environment and meets the general
performance standards. Therefore, the specific performance standards are not ARAR for this
closure. The general closure performance standards would be legally applicable to SA-1, because
it was permitted as a Class IV facility, and are listed in Table 2.1.
mxXB960I.6MC/CJE 2-23 September 16. 1996
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Chapter 1200-l-7-.04(8) of the Rules of the TDEC lists closure and postclosure standards
for Class II solid waste disposal facilities, including final cover and grading requirements,
precipitation run-on/runoff controls, and groundwater monitoring requirements. A compacted
soil cover of 0.9 m (36 in.), of which 0.3 m (12 in.) support vegetative cover, is required [TDEC
1200-l-7-.04(8)(c)(3)(i)]. However, as with the Class IV closure requirements discussed above,
if a site-specific closure plan meets the general performance standards of TDEC 1200-1-7-
.04(8)(a), the TDEC Office of Solid Waste Management can approve it, allowing alternate
closure requirements than those listed in TDEC 1200-1-7-.04(8)(c) (Pugh 1993). In 1986,
SY-200 Yard was closed with a 1.5-m (5-ft) cap of clean soil which is now shown, through the
CERCLA risk assessment, to be protective of human health and the environment and meets the -
general performance standards. Therefore, the specific performance standards are not ARAR for
this closure. The general closure performance standards listed in Table 2.1 would be relevant
and appropriate to closure of the unpermitted SY-200 Yard, which handled industrial wastes.
There are no groundwater monitoring requirements that are applicable or relevant and
appropriate. There are no location-specific ARARs triggered by the selected remedy for Spoil
Area 1 and the SY-200 Yard.
USE OF PERMANENT SOLUTIONS TO THE MAXIMUM EXTENT PRACTICABLE
DOE believes the selected remedy represents the maximum practical extent to which
permanent solutions can be used in a cost-effective manner for the Bear Creek Valley OU 2.
DOE believes the selected remedy provides the best balance of tradeoffs in terms of the nine
CERCLA criteria for alternative evaluation. In general, risk reduction provided by treatment is
not commensurate with additional costs. Although hazardous and radioactive constituents were
detected at the sites, excavation, transport, and treatment of these constituents may result in
negative short-term impacts to the remediation workers and the environment. Waste disturbance
may result in contaminant volatilization or migration through fugitive dust emissions. Also,
treatment of mercury would only result in contaminant transfer from soil to another medium and
not contaminant destruction; therefore, benefits to treatment are minimal. Considering these
potential negative impacts, DOE believes the treatment or resource recovery would not be
practicable. The selected remedy relies on waste covers and institutional controls to protect
human health and the environment without negative impacts to potential receptors.
TT00059601.6MOCJE 2-24 September 16. 1996
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COST EFFECTIVENESS
Actions taken under CERCLA must consider the estimated total present-worth costs of the
alternatives. Alternatives 2 through 5 in the FS meet the regulatory requirements and reduce risk
to human health and the environment to acceptable levels. As shown in Table 2.1, the selected
remedy. Alternative 2, is the least costly of the action alternatives. For SY-200 Yard,
Alternative 3 is almost two times the cost of the selected remedy for similar degrees of
protectiveness. For Spoil Area 1, Alternative 3 is more than four times the cost of the selected
remedy. Alternative 4 is approximately 43 times more costly than the selected remedy for Spoil
Area 1. For SY-200 Yard Alternatives 4 and 5 range from 17 to 19 times more costly than the
selected remedy. Therefore, the selected remedy is the most cost-effective when compared with
the other alternatives considered in the FS.
EXPLANATION OF SIGNIFICANT CHANGES
No significant changes have been made to the remedial action decision selected in the
proposed plan through the regulatory and public comment periods.
REFERENCES
DOE (U.S. Department of Energy). 1995a. Remedial Investigation Report on Bear Creek Valley
Operable Unit 2 (Rust Spoil Area, Spoil Area 1, and SY-200 Yard) at the Oak Ridge
Y-12 Plant, Oak Ridge, Tennessee, DOE/OR/01-1273/V1&D2. Oak Ridge, TN.
DOE. 1995b. Feasibility Study for the Y-12 Bear Creek Valley Operable Unit 2, Spoil
Area 1. SY-200 Yard, and Rust Spoil Area, Oak Ridge, Tennessee, DOE/OR/02-
1279&D2. Oak Ridge, TN.
DOE. 1995c. Proposed Plan for the Y-12 Bear Creek Valley Operable Unit 2. Oak Ridge,
Tennessee, DOE/OR/02-1338&D2. Oak Ridge, TN.
EPA (U.S. Environmental Protection Agency). 1989. Risk Assessment Guidance for
Superfund, Vol. II, Environmental Evaluation Manual, interim final,
EPA/540/1089/001. Office of Solid Waste and Emergency Response, Washington,
DC.
JT0005960I.6MC/CJE 2-25 September 16. 19%
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Pugh, Glen. November 22, 1993. Tennessee Department of Environment and Conservation,
Division of Solid Waste Management, personal communication to L. M. Houlberg.
m«»9601.6MC/aE 2-26 Sqxanber 16, 1996
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PARTS. RESPONSIVENESS SUMMARY
JTOOOSM01.6MC/CIE September 16. 1996
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RESPONSIVENESS SUMMARY
The public was invited to participate in the determination of the selected remedy described
in "Highlights of Community Participation" in Part 2. No public comments were received, and
no modifications have been made to the preferred alternative described in the proposed plan.
JTOOOS9601.6MC/CIE 3-2 September 16. 1996
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