PB94-964054
EPA/ROD/R04-94/183
September 1994
EPA Superfund
Record of Decision:
Upper East Fork Poplar Creek
(O.U. 2), Oak Ridge, TN
9/12/1994
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DOE/OR/02-1265&D2
Record of Decision
for the Upper East Fork Poplar Creek
Operable Unit 2 (Abandoned Nitric Acid Pipeline)
at the Oak Ridge Y-12 Plant
Oak Ridge, Tennessee
Date Issued—July 1994
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 P.estoration and Waste Management
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ACKNOWLEDGEMENTS
Jacobs Engineering Group Inc., under prime contract to the U.S.
Department of Energy, developed this document with the help of the
Jacobs Environmental Restoration Team members:
Geraghty & Miller, Inc.
Lockwood Greene Technologies, Inc.
PAI Corporation
Solutions to Environmental Problems
United Science Industries
University of Tennessee
Additional support was given to the team by Martin Marietta Energy
Systems, Inc.
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CONTENTS
ACRONYMS iv
PART 1. DECLARATION '.' 1-1
SITE NAME AND LOCATION 1-2
STATEMENT OF BASIS AND PURPOSE 1-2
ASSESSMENT OF THE OPERABLE UNIT 1-2
DECLARATION STATEMENT 1-2
PART 2. DECISION SUMMARY 2-1
SITE NAME, LOCATION, AND DESCRIPTION 2-2
SITE HISTORY AND ENFORCEMENT ACTIVmES 2-2
HIGHLIGHTS OF COMMUNITY PARTICIPATION 2-4
SCOPE AND ROLE OF OPERABLE UNIT OR RESPONSE ACTION
SITE CHARACTERISTICS
SUMMARY OF SITE RISKS 2-5
STATUTORY DETERMINATIONS 2-6
EXPLANATION OF SIGNIFICANT CHANGES 2-7
REFERENCES 2-7
PART 3. RESPONSIVENESS SUMMARY 3-1
OVERVIEW ' 3-2
Fig. 1. Location of the Abandoned Nitric Acid Pipeline at the Y-12 Plant 2-3
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ORR
OU
RI
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Oak Ridge Reservation
operable unit
Remedial Investigation
uranium
ACRONYMS
iv
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PART 1. DECLARATION
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SITE NAME AND LOCATION
U.S. Department of Energy
Upper East "Fork Poplar Creek, Operable Unit 2
Abandoned Nitric Acid Pipeline
Oak Ridge Y -12 Plant
Oak Ridge, Anderson County, Tennessee
STATEMENT OF BASIS AND PURPOSE
This document presents the decision for no further action for the Abandoned Nitric Acid
Pipeline at the Oak Ridge Y -12 Plant in Oak Ridge; Tennessee. This alternative is chosen in
accordance with the Comprehensive Environmental Response, Compensation, and Liability Act
of 1980, as amended by the Superfund Amendments and Reauthorization Act of 1986 and, to the
extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan. This
decision is based on the administrative record file for this site. This Record of Decision provides
the public a consolidated source of information about the Abandoned Nitric Acid Pipeline, and
certifies that the Comprehensive Environmental Response, Compensation, and Liability Act
requirements are met.
The state of Tennessee and the U.S. Environmental Protection Agency concur with the
U. S. Department of Energy in this decision for no further action at Upper East Fork Poplar
Creek Operable Unit (OU) 2. .
ASSESSMENT OF THE OPERABLE UNIT
The baselin~ risk as:;~smei1t, conducted ilS pCi&""t of the Remedial Investigation (RI) for the
site, indicates that conditions related to the Abandoned Nitric Acid Pipeline do not pose an
unacceptable threat to human health or the environment. The total carcinogenic risks to either
workers or future homesteaders at the Abandoned Nitric Acid Pipeline from all pathways are
below 10-4, th~ U.S. Environmental Protection Agency's thresholds of concern for remedial
action. Noncarcinogenic hazard indices are below the action level of 1.0 established by the U.S.
Environmental Protection Agency.
DECLARATION STATEMENT
No further remedial action on the soils is necessary to achieve protection of human health
and the environment at the Abandoned Nitric Acid Pipeline. The no further action remedy
protects human health and the environment, complies with federal and state applicable or relevant
and appropriate requirements, and is cost-effective. The baseline risk assessment indicates that
previous cleanup and maintenance activities reduced radiological and hazardous constituents on
the site and in the soils to below levels for unacceptable carcinogenic and noncarcinogenic risk
to human health. 1be groundwater is not addressed as part of this investigation because it will
be addressed as part of the Upper East Fork Poplar Creek OU 1 surface water and groundwater
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investigation. In addition, no significant releases were detected from the- pipeline, therefore, it
is not considered to be a source of groundwater (iinrnmin:lrion. A five-year review does not
apply to this action because the remedy will not leave hazardous substances above action levels
on site .and, OU 1 will continue to explore and address groundwater in future investigations.
There will be no future remedial cost associated with implementing this Record of Decision.
.I::x /~-
Joe LaGro ,Manager
Oak Ridge Operations Office
U.S. Department of Energy
f'/~~
Da£
~~.~~~~. .
Earl C. Leming, Director ~
DOE Oversight Divisi~n
Tennessee Department of Environment and Conservation
~
Date
~trlT~ f'
John Hankinson, Regional Admiriistrator
Region IV
U.S. Environmental ¥rotection Agency
. 9-/2-#
Date
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PART 2. DECISION SUMMARY
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SITE NAME, LOCATION, AND DESCRIPTION
The Y -12 Plant is pan of the Oak Ridge Reservation (ORR) and is located adjacent to the
city of Oak Ridge in Anderson County, Tennessee. Y-12 occupies the upper reaches of East
Fork Poplar Creek and Bear Creek, which lie in the valley between Pine Ridge to the north and
Chestnut Ridge to the south. The Upper East Fork Poplar Creek, OU 2 Abandoned Nitric Acid
Pipeline is a I1h- to 3-inch-diameter underground stainless steel pipe line that runs 4,800 feet east
to west from the H-l Foundry (Building 9215) to the S-3 Ponds (now known as S-3 Site, see Fig.
1). Elevation of the pipe ranges from 1,013.5 feet above mean sea level near the discharge point
to a low of 986 feet above mean sea level near the midpoint.
The Abandoned Nitric Acid Pipeline was used to carry waste effluent from a uranium
recovery process that produced nitric acid and depleted uranium in solution. Materials known
to have been discharged through the pipeline include nitric acid, depleted and enriched uranium,
various metal nitrates, salts, and lead skimmings. The pipeline had many turns, bends, joints,
and low points along its length where waste effluent might have collected or leaked. .
SITE mSTORY AND ENFORCEMENT ACTIVITIES
The Y-12 Plant was built by the U.S. Army Corps of Engineers in 1943 as pan of the
Manhattan Project. The original mission of the plant was to separate 23SU, the fissionable isotope
of uranium, using an electromagnetic separation process. The pr~s stopped after World War
n; the Y -12 Plant was converted to nuclear weapons component fabrication and defense research
missions. Construction of the nitric acid pipeline was completed in October 1951. The pipeline
carried effluent from the H-l Foundry (Building 9215) to the S-3 Ponds. An estimated 5,500
gallons per day of effluent were discharged to the S-3 Ponds. The pipeline was originally buried
0.5 to 14 feet below ground surface, with an average depth of 5 feet. In 1983, the pipeline was
taken out of service by flushing the lines and plugging portions of the pipeline with grout or
concrete. Since then, some sections of the Abandoned Nitric Acid Pipeline have been removed.
No soil samples were apparently taken, but the removed sections were scanned by health physics
personnel, found to meet the acceptance.criteria for the Y-12 Burial Grounds, and were disposed
in the uncontaminated landfill.
The Abandoned Nitric Acid Pipeline was originally pan of the Group 4 Resource
Conservation and Recovery Act Facility Investigation Plan developed between 1988 and 1990.
On December 21, 1989, ORR was added to the National Priorities List, and the four areas being
investigated were separated at the U.S. Environmental Protection Agency's request to be dealt
with as individual OUs under the Comprehensive Environmental Response, Compensation, and
Liability Act. An RI Work Plan for the Abandoned Nitric Acid Pipeline was prepared in 1992,
and phase I of the sampling took place in January and February of 1993. Nineteen points along
the pipeline were selected where leaks had the highest probability of having occurred, and soil
samples were taken from below the pipeline and analyzed for metals, nitrate/nitrite, and isotopic
uranium. Samples were also monitored for organic vapors during excavation; samples with
detectable vapors were analyzed for volatile organic compounds. Since no significant
contamination was found in the phase I sampling, the project was streamlined and the RI Report
was generated without conducting further sampling episodes.
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The Remedial Investigation Report on Abandoned Mtric Acid Pipeline at the Oak Ridge
Y-12 Plant, Oak Ridge, Tennessee was issued in February 1994, and is available at the U.S.
Department" of Energy Information Resource Center located at 105 Broadway in Oak Ridge.
After reviewing the data gathered in the RI and the accompanying risk assessment, and
consultation with regulatory authorities, it was decided that no further action was needed for the
site. Therefore, a feasibility study was deemed unnecessary.
IDGHLIGHTS OF COMMUNITY PARTICIPATION
The Proposed Plan for Upper East Fork Poplar Creek OU 2 Abandoned Nitric Add
Pipeline, was released to the public March 21, 1994. This document. is available in the
administrative record file m~intained at the U.S. Department of Energy Information Resource
Center. The notice of availability was published in the Roane County News on March 18-21,
1994, the Oak Ridger on March 18, 1994, the Qinton Courier on March 24, 1994, and the
Knoxville News Sentinel on March 18-24, 1994. The notice included a statement that a public
meeting concerning the Proposed Plan would be arranged if requested by April 4, 1994. A
public comment period was held from March 21 through April 20, 1994; no public meeting was
requested. No public comments were received as indicated in the Responsiveness Summary,
Part 3 of this No Further Action Record of Decision.
SCOPE AND ROLE OF OPERABLE UNIT OR RESPONSE ACTION
Under the Comprehensive Environmental Response, Compensation, and Liability Act an
OU is defined as a discrete action that is part of a larger area or response action. The strategy
of breaking large areas into OUs is dcsi~ed to address cJI the problems at a site in a more
logical and manageable fashion. Upper East Fork Poplar Creek OU 2 addresses only the soils
along the Abandoned Nitric Acid Pipeline. Groundwater and surface water are addressed within
this OU only to identify potential sources of contamin~tion. Evaluation of any contamination
found in the groundwater or surface water and consideration of remedial alternatives for the water
will be conducted at a later date as part of Upper East Fork Poplar Creek OU 1 RllFeasibility
Study process. The OU concept enables the U.S. Department of Energy to.address potential and
actual sources of contamination early in the remedial process and then investigate and remediate
OUs that collect or integrate the cont~mination migrating from the sources. The Abandoned
Nitric Acid Pipeline does not appear to be an active contributor to water contamination at the Y-
12 Plant Site. Any cumulative human or ecological risk associated with exposure to contamin~ted
surface water or groundwater will be addressed in the integrated OUs for Bear Creek Valley OU
4 and Upper East Fork Poplar Creek OU 1.
SITE CHARACTERISTICS
Topography across the site is undulating with relief as much as 28 feet. Bedrock depth
conforms to the topography and is between 13 and 26 feet below ground surface. The water table
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tends to be situated just above bedrock, and was found to be below the pipelme at all sampling
locations during January and February, 1993. -
The Unconsolidated material in which the pipeline was placed consists of man-made fill
and weathered bedrock. The soils encountered in drilling were very tight clays and saprolite
which inhibit fluid and contaminant migration. No gravel base was found in any of the drilling
locations, suggesting that the pipeline was laid directly on the ground within the trench.
Historically, leaks and pipeline breakage have occurred, but releases from each spill including
any contaminated soil were cleaned up to protect the pipeline workers and others in the area.
The pipeline ran the full length of the historically restricted area, and.passed through both
developed and undeveloped areas of the plant. Exposure of the public and most ecological
receptors are very unlikely since the pipeline is buried underground and within the fenced
operational area of Y -12. Pathways of exposure for workers excavating in the area. near the
buried pipeline may include incidental ingestion, inhalation, dermal contact, and external
exposure.
Data collected at 19 soil sampling points beside and beneath the buried pipeline during the
RI indicate that:
. the Abandoned Nitric Acid Pipeline has not released effluent that has resulted in
contamination of the environment;
. contaminants of potential concern for the Abandoned Nitric Acid Pipeline include
nitrate, nitrite, 234U, 23SU, 238lJ, beryllium, hexavalent chromium, molybdenum, nickel,
and nickel salts; and
. most of the contaminant~ were at or below background levels for the ORR. 238lJ, 23SU,
and beryllium were the main contribators to carcinogenic ri:;k in the Abar.doned Nitric
Acid Pipeline soils, although 231iU was below background, and 233U and beryllium were
only slightly above background concentrations. All contaminants were below action
levels established by the U.S. Department of Energy, the Nuclear Regulatory
Commission, or established and agreed to in the RI Repon.
SUMMARY OF SITE RISKS
Two conservative exposure scenarios were evaluated to determine the potential risk to
hUman health posed by exposure to the contaminated soils surrounding the Abandoned Nitric Acid
Pipeline. The risk assessment for these scenarios was based on current industrial and future
hypothetical residential land uses. The risk assessment based on these scenarios included both
radiological and hazardous chemical constituents, and pathways involving direct soil contact, soil
ingestion, and inhalation of resuspended soil paniculates.
Under conservative conditions, the total excess cancer risk through all exposure pathways
to on-site construction workers was calculared to be approximately 1.9 x 1 (J6. This meam ihat
out of 1 million workers exposed to the Abandoned Nitric Acid Pipeline soils over a 25-year
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period, approximately two (1.9) would have a chance of developing cancer as a result of their
exposure to the radiological contaminants in the soil. The risk to construction workers is only
slightly greater than 1 x 1()"6 (one in a million), the U.S. Environmental Protection Agency-
established risk of no concern. The hypothetical future resident exposure scenario with people
living on the site for 30 years or more estimated the potential excess cancer risk to be about 1.5
x lO-s. This means that out of 100,000 hypothetical future residents living iii the area of
Abandoned Nitric Acid Pipeline, one or two (1.5) people might develop cancer because of
exposure to the radiologically COTltaminated soil. The risk calculated for the future hypothetical
resident is greater than the construction worker risk because the exposure frequency and duration
are assumed to be greater for a resident. However, both of these risk values are below the U.S.
Environmental Protection Agency-established unacceptable risk level of 1.0-x lQ-4 and are within
the U.S. Environmental Protection Agency-established acceptable risk range of 1.0 x 1()"6 (one
-in a million) and 1.0 x lQ-4 (one in 10,000).
The carcinogenic risk estimates represent 95 percent upper confidence limit on the
arithmetic mean, meaning there is only a 5 percent probability that the actual risk will be greater
than that estimated. However, due to the conservative risk assessment assumptions, the actual
risk will most likely be lower than the estimates.'
The hazard index is used to indicate the risk associated with exposure to noncarcinogenic
toxic substances. This index is calculated from the ratio of the hypothetical daily intake of a
substance divided by the estimated daily intake that is unlikely to cause health problems during
a lifetime. The size of the hazard indicates the magnitude of the hazard; the larger the number
the greater the risk. The U.S. Environmental Protection Agency established the threshold of
concern for the hazard index as 1.0 for noncarcinogenic toxicity. The total cumulative pathway
exposure hazard indices for noncarcinogenic risk to construction workers and hypothetical future
residents at the Abandoned Nitric Acid Pipeline site are 0.0047 and 0.052, respectively.
Although both construction worker and residential scenario:; were considered, the
industrial nature of the site suggests that the construction worker scenario is more likely (0 occur.
Therefore, the carcinogenic and noncarcinogenic risks associated with this scenario would be
considered representative of future conditions.
There are no completed exposure pathways for ecological receptors. The Abandoned
Nitric Acid Pipeline is located in a secured, highly industrialized area of' Y -12, and the area is
void of ecological receptors and habitat that would support such receptors. Any cumulative
human or ecological risk associated with exposure to contaminated surface or groundwater will
be addressed in the integrated OUs for Bear Creek Valley OU 4 and Upper East Fork Poplar
Creek au 1.
More information regarding the baseline risk assessment is found in Chapter 5 of the RI.
STATUTORY DETERMINATIONS
The sampling data and the baseline risk assessment indicate soils at the Abandoned Nitric
Acid Pipeline do not pose an unacceptable risk to human health or the environment based on U.S.
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Environmental Protection Agency conservative exposure scenarios. Cont:n~,inanon from past
events at the Abandoned Nitric Acid Pipeline is effectively mitigated in previous cleanup and
maintenance actions. No further remedial actions are necessary to ensure adequate protection of
human he3Ith and the environment under Sections 104 and 106 of the Comprehensive
Environmental Response, Compensation, and Liability ACt.
EXPLANATION OF SIGNIFICANT CHANGES
No significant changes have been made to the no further action decision selected in the
Proposed Plan through the regulatory and public comment periods.
REFERENCES
Martin Marietta Energy Systems, Inc. 1994. Remedial Investigation Repon on the Abandoned
Mtric Acid Pipeline at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee, U.S. Department
of Energy, Oak: Ridge, Tennessee, DOE/ORlOI-1214&D2.
Jacobs ER Team, 1994. Proposed Plan for the Upper East Fork Poplar Creek Operable Unit 2
(Abandoned Mtric Acid Pipeline), Oak: Ridge, Tennessee, DOE/ORl02-121S&D2.
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PART 3. RESPONSIVENESS SUMl\1ARY
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OVERVIEW
The U.S. Department of Energy established a public comment period from March 21
through April 20, 1994, for interested parties to comment on the U.S. Department of Energy's
Proposed Plan for Upper East Fork Poplar Creek OU 2, Abandoned Nitric Acid Pipeline, at the
Oak Ridge Y-12 Plant in Oak Ridge, Tennessee. The Proposed Plan states that no further
remedial action is necessary to protect human health and the environment at the Abandoned Nitric
Acid Pipeline. Also, the baseline risk assessment indicates that previous cleanup and maintenance
activities reduced radiological and hazardous constituents on the site and in the soil below levels
for unacceptable carcinogenic and noncarcinogenic risk to human health and the environment.
The 3o-day public comment period ended on April 20, 1994. No comments on the
Abandoned Nitric Acid Pipeline Proposed Plan were available by that date and no comments were
received by April 25, 1994, the last day to accept mailed comments. In addition, no public
meeting was requested, and none was held.
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