PB95-964616
EPA/ROD/R10-95/126
February 1996
EPA Superfund
Record of Decision:
USDOE Hanford 100 Area, Operable Units
100-BC-l, 100-DR-l and 100-HR-l, WA
9/27/1995
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DECLARATION OF THE RECORD OF DECISION
SITE NAME AND LOCATION
USDOE Hanford 100 Area
100-BC-l, 100-DR-l and 100-HR-l Operable Units
Hanford Site
Benton County, Washington
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected interim remedial actions for portions of the
USDOE Hanford 100 Area, Hanford Site, Benton County, Washington, which were chosen in
accordance with the Comprehensive Environmental Response, Compensation, and Liability
Act of 1980 (CERCLA), as amended by the Superrand Amendments and Reauthorization Act
of 1986 (SARA), and to the extent practicable, the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP). Specifically the selected remedial actions will address 37
high priority waste sites that received liquid radioactive effluent discharges in the 100-BC-l,
100-DR-l and 100-HR-l Operable Units, as well as adjacent contaminated sites that are within
the area required for remediation. This decision is based on the Administrative Record for
this site and for the specific Operable Units.
The State of Washington concurs with the selected remedy.
ASSESSMENT OF THE SITES
Actual or threatened releases of hazardous substances from the waste sites, if not addressed by
implementing the response actions selected in this Record of Decision (ROD), may present an
imminent and substantial endangerment to the public health, welfare, or the environment.
STATEMENT ON THE USE OF INNOVATIVE APPROACHES
The 100 Area of the Hanford Site is complex and contains many individual waste sites within
the area. Based on the circumstances presented by the 100 Area, the use of two innovative
approaches to remediation of the individual waste sites will enhance the efficiency of the
selected remedy. The approaches are the "Observational Approach" and the "Plug-In
Approach".
The Observational Approach relies on information from historical process operations
including historical liquid effluent discharges from 1944 to 1969, and information from
limited field investigations on the nature and extent of contamination, combined with a
"characterize and remediate in one step" methodology. This latter methodology consists of
contingency planning prior to site excavation and field screening for contaminants at sites
where remedial action and cleanup goals have been selected. Remediation proceeds until it
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can be demonstrated through a combination of field screening and confinnational sampling that
cleanup goals have been achieved.
The Plug-In Approach allows for the selection of the same remedy at multiple, similar or
"analogous" sites. In the 100 Area all of the reactor operations, except those in N Area, were
virtually identical, leading to very similar releases of contaminants at similar engineered
structures (retention basins, french drains, cribs, effluent trenches and pipelines, etc). Limited
field investigations at similar sites in different reactor areas has shown similar contaminant
characteristics in engineered structures and soils that received liquid discharges. The Plug-In
Approach allows for the selection and application of the same remedy at similar sites at
multiple reactor locations within the 100 Area where sufficient risk to warrant an action has
been demonstrated either through the results of previous historical sampling, by the limited
field investigation and qualitative risk assessment, and/or by an analogous site type approach
where multiple, similar sites that received similar discharge are assumed to have similar levels
of risks. Under this approach a standard remedy is selected that applies to similar
circumstances, rather than to a specific waste site. This approach allows the U.S.
Environmental Protection Agency (EPA), the U.S. Department of Energy (DOE) and the State
of Washington, Department of Ecology (Ecology), also known as the TriParties to select and
implement remedial actions at multiple, analogous waste sites without expending resources to
initially characterize multiple, similar sites in the 100 Area prior to a ROD. The sites then are
remediated after the ROD. This approach is discussed in greater detail in Sections K and IV.
REDESIGNATION OF 100-DR-l AND 100-HR-l OPERABLE UNITS
The 100-DR-l and 100-HR-l Operable Units were initially designated as RCRA Past Practice
(RPP) units. EPA and Ecology have decided to redesignate these OU's as CERCLA Past
Practice (CPP) units hi order to facilitate the disposal of contaminated materials at the
CERCLA Environmental Restoration Disposal Facility (ERDF). Section 5.4 of the TPA
describes the process that was followed to initially designate OU's as RPP or CPP, and
discusses that the remediation measures selected for OU's under either designation would be
comprehensive to satisfy the technical requirements of both statutory authorities. The primary
consideration for designation was the presence of significant RCRA treatment, storage or
disposal units (TSD's). OU's containing such TSD's were designated as RPP. The TSD's
contained in those OU's are, or will be addressed as part of the RCRA Hanford site-wide
permit. Based on these reasons, the TriParties have agreed to the redesignation of these OU's
to avoid any potential duplication of efforts during remediation. Ecology will remain the lead
regulatory authority for these sites.
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DESCRIPTION OF THE SELECTED REMEDY
The selected remedy for the 100 Area NPL Site addresses actual or threatened releases at high
priority liquid radioactive effluent disposal sites at the 100-BC-l, 100-DR-l and
100-HR-l Operable Units. The major components of the selected remedy include:
o Remove contaminated soil, structures and debris using the Observational Approach.
o Treatment, by thermal desorption to remove organics and/or soil washing for volume
reduction, or as needed to meet waste disposal criteria.
o Disposal of contaminated materials at ERDF.
o Backfill of excavated areas followed by revegetation.
Sites were designated as "high priority" due to potential risks to human health and the
environment. Sites classified as high-priority pose risk(s) through one or more pathways
sufficient to recommend a streamlined action via an interim remedial measure (IRM).
Particular emphasis was given to the waste sites addressed in this ROD due to existing or
potential adverse impacts to underlying groundwater and subsequent contaminant discharges
and potential adverse impacts to the Columbia River. It is expected that some additional sites
also will be remediated that are adjacent to and within the area required for remediation of the
high priority sites addressed in this ROD. This is discussed further in Sections IV and X.
This ROD also provides a decision framework to evaluate leaving some contamination in place
at a limited number of sites, specifically where contamination begins at depths below 15 feet.
The decision to leave wastes in place at such sites will be a site specific determination made
during remedial design and remedial action activities that will balance the extent of
remediation with protection of human health and the environment, disturbance of ecological
and cultural resources, worker health and safety, remediation costs, operation and maintenance
costs, and radioactive decay of short lived [half life less than 30.2 years
(e.g. 137Cesium)J radionuclides. The application of the criteria for the balancing factors, the
process for determining the extent of remediation at deep sites, and the public involvement
process during such determinations shall be specified further in the Remedial Design Report.
This is discussed further in Sections IV, VII, and X.
STATUTORY DETERMINATIONS
This interim action is protective of human health and the environment, complies with federal
and state requirements that are legally applicable, or relevant and appropriate for this interim
action , and is cost effective.
Although this interim action is not intended to fully address the statutory mandate for
permanence and treatment to the maximum extent practicable, this interim action does utilize
treatment and thus is in furtherance of that statutory mandate. Because this action does not
constitute a final remedy for the OU's, the statutory preference for remedies that employ
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treatment that reduces toxicity, mobility or volume as a principal element, although partially
addressed in this remedy, will be addressed further by the final response action. Subsequent
actions are planned to address fully the threats posed by the conditions at these OU's. Because
this remedy will result in hazardous substances remaining onsite above health-based levels, a
review will be conducted to ensure that the remedy continues to provide adequate protection of
human health and the environment within five years after the commencement of the remedial
action. Because this is an interim action ROD, review of this site and of this remedy will be
ongoing as the TriParties continue to develop final remedial alternatives for the OU's and the
100 Area NPL site.
CERCLA Section 104(d)(4) states where two or more non-contiguous facilities are reasonably
related on the basis of geography, or on the basis of the threat or potential threat to the public
health or welfare or the environment, the President may, at his discretion, treat these facilities
as one for the purposes of this section.
The preamble to the NCP clarifies the stated EPA interpretation that when non-contiguous
facilities are reasonably close to one another and wastes at these sites are compatible for a
selected treatment or disposal approach, CERCLA Section 104(d)(4) allows the lead agency to
treat these related facilities as one site for response purposes and, therefore, allows the lead
agency to manage waste transferred between such non-contiguous facilities without having to
obtain a permit. Therefore, the 100 Area NPL site and the ERDF are considered to be a
single site for response purposes under this ROD. This is consistent with the determination
made in the January 20, 1995 ROD for the ERDF that stated... "Therefore, the ERDF and the
100, 200, and 300 Area NPL sites are considered to be a single site for response purposes
under this ROD."
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Signature sheet for the Record of Decision for the USDOE Hanford 100-BC-l, 100-DR-l, and
100-HR-1 Operable Unit Interim Remedial Actions between the United States Department of
Energy and the United States Environmental Protection Agency, with concurrence by the
Washington State Department of Ecology.
_
Micnael Wilson" ' Date
Program Manager, Nuclear and Mixed Waste Program
Washington State Department of Ecology
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Signature sheet for the Record of Decision for the USDOE Hanford 100-BC-l, 100-DR-l, and
100-HR-1 Operable Unit Interim Remedial Actions between the United States Department of
Energy and the United States Environmental Protection Agency, with concurrence by the
Washington State Department of Ecology.
~
/
Chuck Clarke / Date
gional Administrator, Region 10
United States Environmental Protection Agency
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Signature sheet for the Record of Decision for the USDOE Hanford 100-BC-l, 100-DR-l, and
100-HR-l Operable Unit Interim Remedial Actions between the United States Department of
Energy and the United States Environmental Protection Agency, with concurrence by the
Washington State Department of Ecology.
7/
27
John D. Wag^mey Date
Manager, Richland Operations
United States Department of Energy
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TABLE OF CONTENTS
DECLARATION OF THE RECORD OF DECISION i
I. DECISION SUMMARY 1
A. INTRODUCTION 1
B. SITE NAME, LOCATION, AND DESCRIPTION 1
H. SITE mSTORY AND ENFORCEMENT ACTIONS 3
m. HIGHLIGHTS OF COMMUNITY PARTICIPATION 5
IV. SCOPE AND ROLE OF RESPONSE ACTION WITHIN SITE STRATEGY 7
V. SITE CHARACTERISTICS 11
VI. SUMMARY OF SITE RISKS 17
VH. REMEDIAL ACTION OBJECTIVES 24
Vm.DESCRIPTION OF ALTERNATIVES 28
DC. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 31
X. SELECTED REMEDY 35
XI. STATUTORY DETERMINATIONS 39
XH. DOCUMENTATION OF SIGNIFICANT CHANGES 43
Xm.TABLES AND FIGURES 43
APPENDDC A - MODELLING FOR PROTECTION OF GROUND WATER AND THE
COLUMBIA RIVER
APPENDDC B - RESPONSIVENESS SUMMARY
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DECISION SUMMARY
A. INTRODUCTION
The U.S. Department of Energy's Hanford Site was listed on the National Priorities List
(NPL) in July 1989 under the Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA) of 1980 as amended by the Superfund Amendments and
Reauthorization Act (SARA) of 1986. The Hanford Site was divided and listed as four NPL
Sites: the 100 Area, the 200 Area, the 300 Area, and the 1100 Area.
The U.S. Department of Energy (DOE) performed a 100 Area wide Phase 1 and 2 Feasibility
Study, and operable unit specific Limited Field Investigations (LFI's) for the 100-BC-l, 100-
DR-1, and 100-HR-l Operable Units (OU's), which characterized the nature and extent of
contamination in soils, structures, and debris that received radioactive liquid effluent
discharges. Operable unit specific Qualitative Risk Assessments, comprised of human health
risk assessments and ecological risk assessments, also were conducted to evaluate current and
potential effects of contaminants in those OU's on human health and the environment. A 100
Area-wide Phase 3 Source Waste Site Feasibility Study and 100 Area operable unit specific
Focused Feasibility Studies also were conducted to evaluate specific waste site remedial action
goals, objectives and technologies.
B. SITE NAME, LOCATION, AND DESCRIPTION
The Hanford Site is a 1,450km2 (560 mi2) Federal facility located in Benton County in
southeastern Washington along the Columbia River. It is situated north and west of the cities
of Richland, Kennewick, and Pasco, an area commonly known as the Tri-Cities (Figure 1).
Land use in the areas surrounding the Hanford Site includes urban and industrial development,
irrigated and dry-land farming, grazing, and designated wildlife refuges. The region includes
the incorporated cities of Richland, Pasco, and Kennewick (Tri-Cities) and surrounding
communities in Benton, Franklin, and Grant counties. Industries in the Tri-Cities mostly are
related to agriculture and electric power generation. Wheat, com, alfalfa, hay, barley, and
grapes are the major crops in Benton, Franklin, and Grant counties.
The 100 Area, which encompasses approximately 68 km2 (26 mi2) bordering the south shore of
the Columbia River, is the site of the nine retired plutonium production reactors. A brief
summary of the history of reactor operations is presented in Table 1. The reactor facilities
designated as B, C, D, DR. and H are located in the 100-BC-l, 100-DR-l and 100-HR-l
Operable Units (OU's) that are the focus of this ROD. The OU's are shown on Figure 1.
Figures 2, 3, and 4 show the location of waste sites within 100-BC-l, 100-DR-l and
100-HR-l, respectively.
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100 Area Land Use. Pre-Hanford uses included Native American usage and agriculture.
Existing land use in the 100 Area includes facilities support, waste management, and
undeveloped land. Facility support activities include operations such as water treatment and
maintenance of the reactor buildings. The waste management land use designation results
from former uncontrolled disposal activities in areas now known as "past-practice waste sites"
located throughout the 100 Area. Lastly, there are undeveloped lands located throughout the
100 Area that comprise approximately 90 percent of the land area within the 100 Area. These
areas are the least disturbed and contain minimal infrastructure. An 18 mile stretch of the
Columbia River is located within the 100 Area. The shoreline of the Columbia River is a
valued ecological area within the Hanford Site. Portions of the shoreline within the 100 Area
are within the 100 year flood plain of the Columbia River (Figure 5). Semi-arid land with a
sparse covering of cold desert shrubs and drought-resistant grasses dominates the Hanford
landscape. Forty percent of the area's annual average of six and one quarter inches of ram
occurs between November and January. Wetlands along the Columbia River are contained
within the boundaries of the 100 Area NPL Site.
The Hanford Future Site Uses Working Group (the Working Group) in 1992 recommended
that the 100 Area be considered for the following four future use options:
• Native American uses
• Limited recreation, recreation-related commercial use, and wildlife use
B Reactor as a museum and visitor center
Wildlife and recreational use
In addition, that group recommended cleanup of sources and contaminated groundwater flow
into the Columbia River as an "immediate priority". This recommendation was a key
consideration in the selection of high priority liquid radioactive disposal sites for interim
remedial actions that are addressed under this ROD. The recommendations also expressed a
desire for ultimately achieving "unrestricted use" for the air, surface, subsurface, and
groundwater, with the exception of the B Reactor as a museum option. That option would
place the reactor itself in a "restricted" status.
Furthermore, the Final River Conservation Study and the Environmental Impact Statement for
the Hanford Reach of the Columbia River (National Park Service 1994) proposed that the
Hanford Reach of the Columbia River and approximately 102,000 acres of adjacent lands be
designated as a National Wild and Scenic River and a National Wildlife Refuge, respectively.
The final land use for the 100 Area has not been established. For the purposes of this interim
action, the remedial action objectives are for "unrestricted use". Remedial action objectives
and cleanup goals will be re-evaluated if future land use and groundwater use determinations
are inconsistent with the goals presented in this ROD.
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H. SITE HISTORY AND ENFORCEMENT ACTIONS
This section provides a brief overview of the site history, operable unit background and the
primary regulatory considerations for the 100 Area waste sites.
The Hanford Site was established during World War II as part of the "Manhattan Project" to
produce plutonium for nuclear weapons. Hanford Site operations began in 1943, and DOE
facilities are located throughout the Hanford Site and the City of Richland. Certain portions of
the Hanford Site are known to have cultural and historical significance and may be eligible for
listing in the National Register of Historic Places.
In 1988, the Hanford Site was scored using EPA's Hazard Ranking System. As a result of the
scoring, the Hanford Site was added to the NPL in July 1989 as four sites (the 100 Area, the
200 Area, the 300 Area, and the 1100 Area). Each of these areas was further divided into
operable units (a grouping of individual waste units based primarily on geographic area and
common waste sources). The 100 Area NPL site consists of the following operable units for
contaminated sources such as soils, structures, debris, and burial grounds; 100-BC-l, 100-BC-
2, 100-KR-l, 100-KR-2, 100-NR-l, 100-DR-l, 100-DR-2, 100-HR-l, 100-HR-2, 100-FR-l,
100-FR-2, 100-IF-l, 2, 3, and 4; for contaminated groundwater; 100-BC-5, 100-KR-4, 100-
NR-2, 100-HR-3, and 100-FR-3. The actions in this ROD addresses all of the known high
priority liquid effluent disposal sites in the 100-BC-l, 100-DR-l and 100-HR-l OU's. This
ROD will require actions at 37 of the 128 waste sites known to include engineered structures
(out of approximately 300 total known releases) in the 100 Area.
In anticipation of the NPL listing, DOE, EPA, and Ecology entered into a Federal Facility
Agreement and Consent Order in May 1989 known as the TriParty Agreement. This
agreement established a procedural framework and schedule for developing, implementing,
and monitoring remedial response actions at Hanford. The agreement also addresses Resource
Conservation and Recovery Act (RCRA) compliance and permitting.
Operable Unit Background
100-BC-l The 100-BC-l Operable Unit is one of three operable units associated with the 100
B/C Area at the Hanford Site. The 100-BC-l and 100-BC-2 operable units address
contaminant sources while the 100-BC-5 Operable Unit addresses contamination present in the
underlying groundwater. The 100-BC-l Operable Unit encompasses approximately 1.8 km2
(0.7 mi2) and is located immediately adjacent to the Columbia River shoreline. In general, it
contains waste units associated with the original plant facilities constructed to support
B Reactor operation, as well as the cooling water retention basin systems for both B and
C Reactors. The B Reactor, constructed hi 1943, operated from 1944 through 1968, when it
was retired from service. The C Reactor, constructed in 1951, operated from 1952 until 1969,
when it also was retired from service. Currently, the only active facilities hi the lOO^BC-1
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Operable Unit are those that extract and treat water from the Columbia River and transport
that water to other 100 Area and 200 Area facilities.
100-DR-l The 100-DR-l Operable Unit is one of three OU's associated with the 100 D/DR
Area at the Hanford Site. The 100-DR-l and 100-DR-2 are source OU's. The third OU, 100-
HR-3 is the groundwater OU for D/DR and H Areas. The 100 D/DR Area contains two
reactors; the D reactor associated with the 100-DR-l OU, and the DR Reactor associated with
the 100-DR-2 OU. The D Reactor operated from 1944 to 1967 when it was retired. The DR
reactor operated from 1950 to J964_when it was retired. The 100-DR-l OU encompasses
approximately 1.5 km2 (0.59 mi2) and is immediately adjacent to the Columbia River.
Currently, sanitary and fire protection water is provided to the 100-H and 100-F Areas from
the 100 D Area,
100-HR-l The 100-HR-l Source Operable Unit is one of two source operable units
associated with the 100-H Area at the Hanford Site. The 100-HR-l and 100-HR-2 Source
Operable Units address contaminant sources while the 100-HR-3 Groundwater Operable Unit
addresses contamination present in the underlying groundwater. The 100-HR-l Source
Operable Unit encompasses approximately 0.41 km2 (0.16 mi2) and is located immediately
adjacent to the Columbia River shoreline. The operable unit contains waste units associated
with the original plant facilities constructed to support the H Reactor. The area also contains
evaporation basins which received liquid process wastes and non-routine deposits of chemical
wastes from the 300 Area, where fuel elements for the N Reactor were produced. These solar
evaporation basins received wastes from 1973 through 1985 and are regulated under RCRA as
treatment, storage, and disposal facilities. The H Reactor complex was constructed after World
War n to produce Plutonium for use in military weapons. The H Reactor operated from 1949
to 1965, when it was retired. Currently there are no active facilities, operations, or liquid
discharges within the 100-HR-l Source Operable Unit.
Tables 2, 3, and 4 present summary information regarding the 27 high priority liquid
radioactive effluent disposal sites evaluated in the OU-specific FFS reports. An additional 10
high priority liquid radioactive effluent disposal sites presented in Table 5 also are included in
this ROD for remedial action. Analyses by EPA and Ecology, and documented in the
Administrative Record, concluded that the 10 additional sites warrant remedial action based on
the Plug-In or analogous site type approach (i.e. similar historical discharges and limited
sampling is indicative of comparable, elevated risk levels such that remedial action is
warranted). Table 5 also indicates an analogous site for each of the 10 additional sites from
the list of 27 sites from the OU-specific FFS Reports. Additional discussions of these waste
sites and their inclusion in this ROD and the Plug-In approach are presented in Sections IV
andV.
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III. HIGHLIGHTS OF COMMUNITY PARTICIPATION
DOE, Ecology, and EPA developed a Community Relations Plan (CRP) in April, 1990 as part
of the overall Hanford Site restoration. The CRP was designed to promote public awareness
of the investigations and public involvement in the decision-making process. The CRP
summarizes known concerns based on community interviews. Since that time several public
meetings have been held and numerous fact sheets have been distributed in an effort to keep
the public informed about Hanford cleanup issues. The CRP was updated in 1993 to enhance
public involvement and is scheduled to be updated again this year.
The 100 Area Focused Feasibility Study Document and Proposed Plans for 100-BC-l, 100-
DR-1 and 100-HR-1 were made available to the public in both the Administrative Record and
the Information Repositories maintained at the locations listed below on June 26, 1995.
A fact sheet, which explained the proposed action, was mailed to approximately 2,000 people.
In addition, an article appeared in the bi-monthly newsletter, the Hanford Update, detailing the
start of public comment. The Hanford Update is mailed to over 5,000 people. The Proposed
Plans were mailed to all of the members of the Hanford Advisory Board.
ADMINISTRATIVE RECORD (Contains all project documents)
U.S. Department of Energy
Richland Operations Office
Administrative Record Center
740 Stevens Center
Richland, Washington 99352
EPA Region 10
Superfund Record Center
1200 Sixth Avenue
Park Place Building, 7th Floor
Seattle, Washington 98101
Washington State Department of Ecology
Administrative Record
300 Desmond Drive
Lacey, Washington 98503-1138
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INFORMATION REPOSITORIES (Contain limited documentation)
University of Washington
Suzzallo Library
Government Publications Room
Mail Stop FM-25
Seattle, Washington 98195
Gonzaga University
Foley Center
E. 502 Boone
Spokane, Washington 99258
Portland State University
Branford Price Millar Library
Science and Engineering Floor
SW Harrison and Park
P.O. Box 1151
Portland, Oregon 97207
DOE Richland Public Reading Room
Washington State University, Tri-Cities
100 Sprout Road, Room 130
Richland, Washington 99352
The notice of the availability of these documents was published in the Seattle Pi/Times, the
Spokesman Review-Chronicle, the Tri-City Herald, and the Oregonian on June 25, 1995 and
again on June 26, 1995. Additional advertisements ran in the Tri-City Herald on June 23,
1995 and June 24, 1995. The public comment period was held from June 26, 1995, through
August 9, 1995. A public meeting was held on July 25, 1995 at the Richland Public Library.
At the meeting, representatives from DOE, EPA and Ecology answered questions about the
project. A response to the comments received during the public comment period, including
those raised during the public meeting, is included in the Responsiveness Summary, which is
attached as Appendix B to this ROD. This decision document presents the selected interim
remedial action at high priority liquid radioactive effluent disposal sites in the 100-BC-l, 100-
DR-1 and 100-HR-l OU's at the Hanford Site in Richland, Washington. The selected interim
remedy is chosen in accordance with CERCLA, as amended by SARA, and to the extent
practicable, the NCP. The decision for these sites is based on the Administrative Record.
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IV. SCOPE AND ROLE OF RESPONSE ACTION WITHIN SITE STRATEGY
This section describes the objectives of the selected interim remedial action and how it fits
within the overall site remediation strategy, and discusses the application of the Plug-In
(analogous site type) Approach, and the Observational Approach consistent with the Hanford
Past Practices Strategy.
Objectives These interim actions are intended to significantly reduce risks associated with
liquid radioactive effluent disposal practices. Therefore, these interim actions are limited in
scope and will be followed by additional actions (interim and/or final) for other contaminated
source waste sites and groundwater in order to provide long-term protection of human health
and the environment. This interim action will be consistent with any future planned actions.
The interim cleanup actions described in this ROD address all known current and potential
risks to human health and the environment from the high priority liquid radioactive effluent
disposal sites in the 100-BC-l, 100-DR-l and 100-HR-l OU's. Sites classified as
high-priority pose risk(s) through one or more pathways sufficient to recommend an
accelerated response via an interim remedial measure (IRM). This ROD addresses
contaminated soils, structures, and debris found at these sites, but does not address
groundwater that has been contaminated by releases from these sites. Other source units and
groundwater contamination in the 100 Area will be addressed in future proposed plans and
records of decision. Any remaining risks will be addressed in a final ROD for the 100 Area
NPLsite.
The interim remedial action selected by this document has the following specific remedial
action objectives:
o Protect human and ecological receptors from surface exposure to contaminants in soils,
structures, and debris by exposure, inhalation, or ingestion of radionuclides, inorganics or
organics.
d Control the sources of groundwater contamination to minimize the impacts to groundwater
resources, protect the Columbia River from further adverse impacts, and reduce the degree of
groundwater cleanup that may be required under future actions.
o Provide the highest degree of protection of human health and the environment through
removal and disposal of the mass of contamination to the maximum extent practicable, such
that institutional controls and/or long-term monitoring are not required.
These objectives will be achieved through implementation of the remove, treat as appropriate
or required, and dispose alternative.
Plug-In Approach This ROD also provides a regulatory framework for a "Plug-In" or
"Analogous Site" approach for input to remediation decisions in place of a rigorous site
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characterization effort that is often conducted during a remedial investigation. The analogous
site approach relies on historical data, operational knowledge (particularly discharge and
disposal practices), and characterization data from similar sites to determine if there is
sufficient "analogous information" to proceed with a decision to initiate remediation of other,
less characterized site(s) through the Observational Approach. The Observational Approach in
turn relies on combining characterization and remediation steps in order to maximize the use
of resources. The Observational Approach is discussed in greater detail in this section under
the Hanford Past Practice Strategy. Figure 6 presents the conceptual model for analogous
sites in the 100 Area, and Table 6 presents specific analogous sites in the
100-BG-l, 100-DR-l and 100-HR-l Operable Units.
Hanford Past Practice Strategy and the 100 Area The Hanford Past Practice Strategy
(HPPS) was developed to address a number of concerns at Hanford related to streamlining
investigation activities and achieving rapid, more effective application of resources towards
cleanup actions. These concerns included improving RCRA/CERCLA integration to provide
greater uniformity in the application of statutory requirements at the Hanford Site;
streamlining the CERCLA approach such that a limited budget could be more effectively
applied to cleanup actions; and to coordinate past-practice investigations with RCRA closure
activities, since some operable units contain RCRA treatment, storage, and disposal facilities.
Figure 7 presents a decision flow chart for the HPPS process. The strategy includes three
paths for interim decisions, and the final remedy-selection process, for operable units that
incorporates the three paths and integrates sites not addressed in those paths.. An important
element of this strategy is the application of the Observational Approach, in which
characterization data are collected concurrently with cleanup. As shown on Figure 7, the three
paths for interim decisions are as follows:
• Expedited response action path, where an existing or near-term unacceptable
health or environmental risk from a site is determined or suspected, and a rapid
response is necessary to mitigate the problem.
• Interim remedial measures path, where existing data are sufficient to formulate
a conceptual model and perform a QRA. If a determination is made that a site
continues to be a candidate for an IRM, the process will proceed to select an
IRM remedy, and may include a focused FS, if needed, to select a remedy.
Limited field investigation path, where an LFI can provide sufficient data to
formulate a conceptual model and to perform a QRA and implement an IRM.
The interim actions in this ROD address sites classified as high-priority that pose a potential
adverse risk(s) through one or more exposure pathways, any of which are sufficient to warrant
a streamlined action via the IRM path.
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In order to enhance the efficiency of ongoing remedial activities at the 100 Area of the
Hanford Site, and to expedite the ultimate goal of cleanup, more emphasis has been placed on
initiating and completing waste site cleanup through IRM's. This strategy streamlines the
past-practice remedial action process and places emphasis on the following:
• Accelerating decision-making by maximizing the use of existing data consistent
with data quality objectives.
• Undertaking expedited response actions (ERA's) and/or IRM's, as appropriate,
to either remove threats to human health and welfare and the environment, or to
reduce risk by reducing toxicity, mobility, or volume of contaminants.
This ROD also provides a decision framework to evaluate leaving some contamination in place
at a limited number of deep sites, specifically where contamination begins at depths below 15
feet. The specific sites are discussed below. The decision to leave wastes in place at such
sites will be a site specific determination made during remedial design and remedial action
activities. Several factors will be considered in determining the extent of remediation
including reduction of risk by decay of short-lived (half life of less than 30.2 years)
radionuclides, protection of human health and the environment, remediation costs, sizing of
the Environmental Restoration Disposal Facility, worker safety, presence of ecological and
cultural resources, the use of institutional controls, and long term monitoring costs. In the
event that an evaluation is being considered that could allow for contaminated soil to be left in
place, additional public comment will be requested, and long-term groundwater monitoring
will be required. The application of the criteria for the balancing factors, the process for
determining the extent of remediation at deep sites, and the public involvement process during
such determinations shall be specified further in the Remedial Design Report.
In addition, fate and transport modeling will be utilized that will include, but not be limited to,
such factors as contaminant specific and site specific hydrologic and geochemical parameters.
Initial modeling that has been performed to date has relied on the Summers Model, an EPA
approved, one-dimensional solute transport model. Additional information on the model and
the preliminary input parameters is contained in Appendix A. It is expected that input
parameters may vary from those presented in Appendix A based on site specific conditions, as
well as the development of additional information during remedial design and remedial action
activities.
Based on existing knowledge, it is possible that six of the thirty seven sites may be candidates
for leaving residual wastes in place through the application of the decision framework due to
the presence of a potentially large volume of relatively low level of radioactive wastes that
have been encountered initially at depths below 15 feet. Those six sites are the 116-B-l
Process Effluent Trench, 116-B-l 1 Retention Basin, 116-C-l Process Effluent Trench, 116-
DR-9 Retention Basin, 116-D-2B Crib and the 116-H-7 Retention Basin. In the event such
an evaluation is given consideration for those six sites, or other sites that exhibit similar
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characteristics, during remedial design or remedial action activities, additional public comment
will be requested and an Explanation of Significant Differences provided.
For sites where contamination above the 15 mrem/year residential dose is present both above
and below a depth of 15 feet, remediation will continue to the bottom of the engineered
structure, at a minimum. In the event that a determination is made for sites that fall into either
of the above categories, that contamination levels are present below the fifteen foot level and
in the vadose zone beneath a site at levels that exceed 15 mrem/year dose, but are below levels
that are projected through modeling activities to be protective of groundwater and the
Columbia River, the following actions will be required; a request for additional public
comment and an Explanation of Significant Differences will be provided; groundwater
monitoring until such time that short-lived radionuclides have been demonstrated to have
undergone sufficient half life decay (minimum of five half lives since the cessation of liquid
effluent disposal practices) to levels that would pose no threat to groundwater or the Columbia
river under unrestricted future use; and institutional controls to prevent intrusion until such
time that long-term monitoring has demonstrated that any residual risk is below levels that
would allow for any, unrestricted use.
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V. SITE CHARACTERISTICS
This section presents an overview of the physical characteristics of the 100 Area, available
historical data that was evaluated, summaries of the 100 Aggregate Area Studies, and the
results of the 100-BC-l, 100-DR-l and 100-HR-l Operable Unit-specific waste site
evaluations.
Site Geology and Hydrology The Hanford Site is located in the Pasco Basin, a topographic
and structural basin situated in the northern portion of the Columbia Plateau. The plateau is
divided into three general structural subprovinces: the Blue Mountains; die Palouse; and, the
Yakima Fold Belt. The Hanford Site is located near the junction of the Yakima Fold Belt and
the Palouse subprovinces. A northeast to southwest geological cross section of the 100 Area is
presented in Figure 8. Generalized geologic structural maps of the 100-BC-l Area, and the
100-DR-l and 100-HR-l Areas are presented in Figures 9 and 10, respectively.
Geology. The 100 Area is located in the northern portion of the Hanford Site, adjacent to the
Columbia River. The geologic structure beneadi the 100 Area is similar to much of the rest of
the Hanford Site, which consists of three distinct levels of soil formations. The deepest level
is a thick series of basalt flows that have been warped and folded, resulting in protrusions that
crop out as rock ridges in some locations. The top of the basalt in the 100 Area ranges in
elevation from 46 m (150 ft) near the 100-H Area to 64 m (210 ft) below sea level near the
100-B/C Area. Layers of silt, gravel, and sand known as the Ringold formation form the
middle level. The Ringold Formation shows a marked west-to-east variation in the 100 Area.
The main channel of the ancestral Columbia River flowed along Umtanum Ridge and through
the 100-B/C and 100-K areas, before turning south to flow along Gable Mountain and/or
dirough the Gable Mountain-Gable Butte gap, leaving relatively thin deposits of sand and
gravel in the 100-B/C and 100-K Areas. The uppermost level is known as the Hanford
formation and consists of gravel and sands deposited by catastrophic floods during glacial
retreat. In the 100 Area, the Hanford formation consists primarily of Pasco Gravels facies,
with local occurrences of the sand-dominated or slackwater facies. The predominant soil types
in this area are Burbank loamy sand (34%), Ephrata sandy loam (23%), Ephrata stony loam
(23%), and Quincy sand (17%). Other soil types include Pasco silt loam, Kiona silt loam, and
river wash.
Groundwater Groundwater in the 100-B/C Area flows in a northerly direction towards the
Columbia River. The depth to groundwater at high river stage ranges from 22.89 m (75.1 ft)
in well 199-B4-4, located near the B Reactor, to 15.06 m (49.41 ft) in well 199-B3-47, located
due north of the 116-B-14 sludge disposal trench. The estimated hydraulic conductivities in
the uppermost aquifer range from 2 x 10"2 cm/s (50 ft/day) to 5 x 10° cm/s (15 ft/day).
Groundwater in the 100-D/DR Area flows in a north/northwest direction towards die
Columbia River. The depth to groundwater ranges from 22.67 m (74.4 ft) south of D Reactor
in well 199-D2-5 to 17.0m (55.8 ft) near the Columbia River in well 199-D8-53.
Groundwater in the 100-H Area generally flows in a northeasterly direction towards the
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Columbia River. The groundwater table elevation (above mean sea level) at normal to low
river stage ranges from 377 feet (ft) (114.9 m) in the southwest corner to approximately 374 ft
(113.9 m) near the river. The groundwater gradient is approximately 0.0006. Typical
hydraulic conductivities in the uppermost aquifer (Ringold Formation) range from 6.9 x 10"*
cm/s (2 ft/d) to 2.3 x 10° cm/s (6 ft/day).
Columbia River The Columbia River is the second largest river in North America and the
dominant surface-water body on the Hanford Site. The existence of the Hanford Site has
precluded development of this section of river for irrigation and power. The Hanford Reach is
now being considered for designation as a National Wild and Scenic River as a result of
congressional action in 1988. The uses of the Columbia River include the production of
hydroelectric power, extensive irrigation in the Mid-Columbia Basin, and as a transportation
corridor for barges. Several communities located on the Columbia River rely on the river as
their source of drinking water. Water from the Columbia River along the Hanford Reach is
also used as a source of drinking water by several onsite facilities and for industrial uses. In
addition, the Columbia River is used extensively for recreation, including fishing, hunting,
boating, sailboarding, waterskiing, diving, and swimming.
Historical Data An integral part of the 100 Area investigations was the acquisition,
evaluation, and utilization of records pertaining to the construction, operation, and
decontamination/decommissioning of the reactors and related facilities. This information is
categorized as historical information and includes operations records and reports, engineering
drawings, photographs, interviews with former or retired operations personnel, and data from
sampling and analysis of facilities and the local environment.
A primary reference for radiological characterization of the 100 Area Operable Unit sources is
a sampling study of the 100 Area performed during 1975-76 by Dorian and Richards. In die
100 Area Source Operable Unit areas, Dorian and Richards collected samples from retention
basins, effluent pipelines and surrounding soil, liquid waste disposal trenches, retention basin
sludge disposal trenches, miscellaneous trenches, cribs, french drains, and dummy
decontamination drains. Samples of soil were collected from die surface and subsurface to a
maximum of 11.6m (38ft) below grade in the 100-B/C area, and 7.6 m (25ft) below grade in
the 100-D/DR and 100-H Areas. Samples were also collected from retention basin sludge and
concrete and from effluent line scale and sludge. The samples were analyzed for
radionuclides. Inventories of radionuclides for the facilities and sites were calculated. Results
from Dorian and Richards were a major resource used in the development of the 100-Area
conceptual models and LFI data needs. It should be noted, however, that only concentrations
and inventories of selected radionuclides were reported in the 1975-76 study. In particular,
Ni-63, which is generally present at activities on the same order of magnitude as Co-60, was
reported for only some samples; Tc-99 was not evaluated; and daughter product radionuclides
of Sr-90 and Cs-137, which have approximately the same activities as die parent nuclides,
were not included in summaries of total activity. '
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100 Area Aggregate Studies The 100 Area aggregate studies and Hanford Site studies
provide integrated analyses of selected issues on a scale larger than the operable unit, such as
the Hanford Site background study. The 100-HR-3 Work Plan (DOE-RL 1992) addresses
activities common to the 100 Area such as a river impact study, a shoreline study, an
ecological study, and a cultural resource study. These studies provide data that was used in
the OU-specific LFI reports. Results of the Hanford Site background study, the 100 Area
ecological study, and cultural resource study that are applicable to the 100 Area OU's are
summarized below.
Background Study The evaluation of levels of naturally occurring constituents in Hanford
area soils and groundwater was undertaken in order to better understand baseline conditions
against which to evaluate potential cleanup levels and actions. A report on inorganic
constituents in soils was released in May, 1994 by DOE. A summary of those results is
presented in Table 7. Preliminary results of the evaluation of radionuclides in soils was
released in July 1995 by DOE. A summary of those results is presented in Table 8. For the
purposes of the interim actions discussed in this ROD, background considerations for
radionuclides is being considered in terms of mrem/year dose, and then by specific analyte(s)
as appropriate. For the 100 Area, the average background dose associated with radionuclides
in soils is approximately 60 mrem/year, and the 95 % upper confidence limit (UCL) dose is
approximately 78 mrem/year.
Ecological Analysis Ecological surveys and sampling have been conducted in the 100 Areas
and in and along the Columbia River adjacent to the 100 Areas (Sackschewsky and Landeen
1992; Weiss and Mitchell 1992). Sampling included plants with either a past history of
documented contaminant uptake or an important position in the food web, such as river algae,
reed canary grass, tree leaves, and asparagus. In addition, samples were collected of caddisfly
larvae (next step in the food chain from algae), burrow soil excavated by mammals and ants at
waste sites, and pellets cast by raptors and coyote scat to determine possible contamination of
the upper end of die food chain. Bird, mammal, and plant surveys were conducted and
reported in Sackschewsky and Landeen. Current contamination data have been compiled from
other sources, along with ecological pathways and lists of all wildlife and plants identified at
die site, including threatened and endangered species. This information has been published in
Weiss and Mitchell." Summaries of identified threatened, endangered and candidate species
under the Endangered Species Act from diose studies are presented in Tables 9 and 10.
Cultural Resources Review In compliance with Section 106 of die National Historic
Preservation Act the Hanford Cultural Resources Laboratory conducted an archaeological
survey during fiscal year 1991 of the 100 Area reactor compounds on the Hanford Site. This
survey was conducted as part of a comprehensive cultural resources review of the 100 Area
operable units in support of CERCLA characterization activities. The work included a
literature and records review and pedestrian survey of the project area, following procedures
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presented in the Hanford Cultural Resources Management Plan. A summary of those survey
efforts is discussed below. ,
The surveys located three historic and five prehistoric sites within the 100-D/DR and 100-H
Areas which could be potentially impacted by IRM activities. Two historic sites (designated
as 3-176 and 3-178) have the potential of being impacted by construction and support activities
in the 100-H Area. One historical site (3-180) and one prehistoric site (45BN176) have the
potential of being impacted in the 100-D/DR Areas. Four additional prehistoric sites
(45BN147, 45BN148, 45BN439, and 45BN459) are near the river in the 100-D/DR Areas in
potential zones for IRM activities. Three of these sites are village sites with pit houses. In the
100-B/C Area, two archeological sites (H3-17 and 45BN446) and a single isolated artifact
(45BN430) were located. Site H3-17 and 45BN446 are in areas that may potentially be
affected by IRM activities. All of the potential impact sites within the 100 Area OU waste
sites associate with the IRM activities under this ROD need to be evaluated for eligibility for
National Historical Registry Places. Any sites found eligible for listing should be avoided
during remedial actions or plans for data recovery/mitigation will be required.
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Nature and Extent of Contamination and Investigative Approach The results of the 100
Area investigations are described in the following paragraphs.
Limited Field Investigations (LFI's) were undertaken for the 100 Area OU's in a manner
consistent with the HPPS for waste sites that were considered to be candidates for IRM's. The
LFI included data compilation, non-intrusive investigations, intrusive investigations, 100 Area
aggregate studies, and data evaluation. The purpose of the LFI reports were to identify those
sites that are recommended to be candidates for IRM's, provide a preliminary summary of site
characterization studies, refine the conceptual model as needed, identify contaminant- and
location-specific applicable or relevant and appropriate requirements (ARAR's), and provide a
qualitative assessment of the risks associated with the sites. The assessments included
consideration of whether contaminant concentrations pose an unacceptable risk that warrants
action through IRM's. An IRM as defined by the HPPS is in broad terms and is not restricted
to limited and/or near-term actions. A decision to conduct an IRM relies on many factors
including potential adverse risks, ARAR's, future land use, point of compliance, time of
compliance, a bias-for-action as discussed in the HPPS, and potential threats to human health
and the environment. IRM's are intended to achieve remedies that are expected to be
consistent with final actions and a final Record of Decision.
Summaries of the physical description and contaminated media of the waste sites addressed in
this ROD for 100-BC-l, 100-DR-l and 100-HR-l are presented in Table 11. Tables 12, 13,
and 14 present summaries of the maximum concentrations of radionuclides and other
contaminants at the 100-BC-l 100-DR-l and 100-HR-l liquid waste radioactive effluent
disposal sites. An overview of the results of the LFI's for the 100-BC-l, 100-DR-l and
100-HR-l Ou's is discussed below.
NOTE: The volume estimates of the nature and extent of contamination presented in Tables
12, 13 and 14 are based on conservative assumptions. Contamination was assumed to be
homogeneous throughout the engineered structure, and in the vadose zone beneath the waste
site. Contaminant levels were assumed to be at the 95 % UCL level. Based on experience at
remediation during the 100-BC-l ERA, actual contaminated volumes are expected to vary from
preliminary estimates.
100-BC-l Analyses of LFI samples from high-priority sites did not detect any pesticides or
polychlorinated bi-phenyls (PCB's) (Aroclor 1260) and only low levels of volatile organic
compounds (VOC's) were found. The presence of VOC's (methyiene chloride, acetone,
toluene) are most likely the result of contamination present in the analytical laboratories. The
detected semi-volatile compounds include typical constituents in creosote and other wood
preservatives such as chrysene and pentachlorophenol. These semi-volatile compounds were
detected hi concentrations below the EPA Contract Lab Program, contract-required
quantitation limits. Timbers used to construct the cribs and the wood baffles in the retention
basins may be sources for these compounds. "Contamination by metals (chromium, mercury)
was found at 116-B-l, 116-B-3, 116-B-5, and at the highest concentrations in the 116-C-5
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sludge. Radionuclide contamination was also greatest in the 116-C-5 sludge, and present in all
other sampled high-priority waste sites.
100-DR-l Analyses of samples from high-priority sites detected pesticides, PCB's,
semivolatile organic compounds and VOC's. The presence of VOC's (methylene chloride,
acetone, toluene) are most likely the result of contamination present in the analytical
laboratories. The detected semi-volatile compounds included typical constituents in creosote
and other wood preservatives such as chrysene and pentachlorophenol. Metals contamination
was found at 116-D-1A, 116-D-1B, 116-D-7, 116-DR-9, 116-DR-l, 166-DR-2, 116-D-3, 130-
D-l and the sodium dichromate tanks site. The highest concentrations of metals were found in
soil samples at the 116-D-1A site. Radionuclide contamination was highest at the 116-DR-9
site, and was present in all of the high priority sites that were sampled.
100-HR-l Analysis of LFI samples from the high-priority sites did not detect any pesticide or
PCB compounds and only three VOC's were found. The presence of VOC's (methylene
chloride, acetone, toluene) are most likely the result of contamination from analytical
procedures used in the off-site analytical laboratories. The detected semi-volatile compounds
included typical constituents in coal tars and creosote such as chrysene and pentachlorophenol.
The source of this contamination is likely creosote treated timbers and pipes. Timbers were
used to construct the cribs and the wood baffles in the retention basins. Contamination by
metals was found at the 116-H-7 retention basin and the 116-H-l trench. Radionuclide
contamination was detected at these sites, and at the 116-H-3 drain where a very small
concentration of U2Eu was detected. Radionuclide contamination was detected at all five sites
investigated during the LFI. The 116-H-7 retention basin and the 116-H-l trench had the
highest detected concentrations of man-made radionuciides.
For the 100 Area LFI reports, the historical data (Dorian and Richards 1978) were found to be
generally reliable in predicting the probability of radionuclide contamination but unreliable in
predicting the levels of contamination. The historical analytical results were consistently
found to indicate levels of radionuciide contamination one to three orders of magnitude higher
dian the LFI data. The cause of this disparity is unclear but may be due to differences in
analytical instrumentation accuracy or sampling locations.
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VI. SUMMARY OF SITE RISKS
This section presents an overview of the risk assessment methodology and the qualitative risk
evaluations undertaken as part of the assessment of waste sites at the 100-BC-l, 100-DR-l and
100-HR-l OU's, the results and significant contaminants that are of primary concern for
remediation, and the assumptions and uncertainties associated with the risk evaluations.
The qualitative risk assessment consisted of contaminant identification, exposure assessment,
toxicity assessment, and human health as well as ecological risk characterization. The
contaminants of concern were identified based on historical sampling data and radionuclide
inventories as well as from the results of the limited field investigation studies. The exposure
assessment identified potential exposure pathways for future residential or recreational users.
The toxicity assessment evaluated the potential health effects to human or ecological receptors
as a result of exposure to contaminants. Exposure scenarios were developed to evaluate
potential future land use scenarios (residential and recreational) in which the onset of
exposures are delayed until the year 2018, based on the TPA target date for completion of
remediation in the 100 Area. The primary objective of the results of the QRA 's was to make a
"yes or no" determination with respect to whether a site should be considered as a candidate
for an interim remedial measure (IRM).
Qualitative Risk Assessment (QRA) Methodology The QRA methodology consisted of an
evaluation of risk for a defined set of human and environmental exposure pathways and
scenarios. It is not intended to be a replacement or substitute for a baseline risk assessment.
For the 100 Area waste sites addressed in this ROD, the QRA considered two human health
exposure scenarios (residential use and recreational use) with four exposure pathways (soil
ingestion, fugitive dust inhalation, inhalation of volatile organic compounds from soil, and
external radiation exposure), and a limited ecological assessment. The ecological assessment
concentrated on potential adverse effects to the Great Basin pocket mouse. The pocket mouse
has a home range that approximates the size of many of the waste sites. Furthermore, the
pocket mouse is a key part of the terrestrial food chain at Hanford for the loggerhead shrike, a
candidate endangered species.
Adverse effects resulting from exposure to chemical contaminants are identified as either
carcinogenic (i.e. causing development of cancer in one or more tissues or organ systems) or
non-carcinogenic (i.e., direct effects on organ systems, reproductive and developmental
effects). Figure 11 presents a conceptual model of the contaminant exposure pathways.
High priority sites that are addressed in this ROD pose risk(s) through one or more pathways
sufficient to recommend a streamlined action via an IRM.
Identification of Contaminants of Concern contaminants of concern were identified through
an evaluation of both historical data and LFI data. Contaminants that were present in the top
4.6 meters (15 ft) of soil were included in the evaluation. The higher concentration from
either the historical data set or the LFI were selected for evaluation in the QRA. A
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preliminary risk based screening for contaminants was performed using the residential scenario
at a lifetime incremental cancer risk (ICR) of 1 x 10'7, and a hazard quotient of 0.1.
Toxicity Assessment All radionuclides are classified by EPA as Group A human carcinogens
due to their property of emitting ionizing radiation. For radium, this classification is based on
direct human epidemiological evidence. For the remaining radionuclides, this classification is
based on the knowledge that these elements are deposited in the body, delivering calculable
doses of ionizing radiation to the tissues. Despite differences in radiation type, energy or half-
life, the health effects of ionizing radiation are identical, but may occur in different target
organs and at different activity levels. Cancer induction is the primary human health effect of
concern resulting from exposure to radioactive environmental contamination, since the
concentrations of radionuclides associated with significant carcinogenic effects are typically
orders of magnitude lower than those associated with systemic toxicity. The cancers produced
by radiation cover the full range of carcinomas and sarcomas, many of which have been shown
to be induced by radiation. EPA's Health Assessment Summary Tables (HEAST; EPA 1992)
and Eisenbud (1987) are used as the source of radionuclide information including half-lives,
lung class, gastro-intestinal (GI) absorption, and slope factors.
Quantification of Carcinogenic Risk For carcinogens, risks are estimated as the likelihood
of an individual developing cancer over a lifetime as a result of exposure to a potential
carcinogen (i.e., incremental or excess ICR). The equation for risk estimation is:
ICR = (Chronic Daily Intake) (Slope Factor)
This linear equation is only valid at low-risk levels (i.e., below estimated risks of 1 x 10'2),
and is an upperbound estimate of the upper 95th percent confidence limit of the slope of the
dose-response curve. Thus, one can be reasonably confident that the actual risk is likely to be
less than that predicted. Contaminant-specific ICR's are assumed to be additive so that ICR's
can be summed for pathways and contaminants to provide pathway, contaminant, or subunit
ICR's.
Quantification of Non-Carcinogenic Risk Potential human health hazards associated with
exposure to noncarcinogenic substances, or carcinogenic substances with systemic toxicities
other than cancer, are evaluated separately from carcinogenic risks. The daily intake over a
specified time period (e.g., lifetime or some shorter time period) is compared to an RfD for a
similar time period (e.g., chronic RfD or subchronic RfD) to determine a ratio called the
hazard quotient (HQ). Estimates of intakes for both the residential and recreational scenarios
are based on chronic exposures. The nature of the contaminant sources and the low
probability for sudden releases of contaminants from the subunits preclude short-term
fluctuations hi contaminant concentrations that might produce acute or subchronic effects.
The formula for estimation of the HQ is: HQ = Daily Intake/RfD
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If the HQ exceeds unity, the possibility exists for systemic toxic effects. The HQ is not a
mathematical prediction of the severity or incidence of the effects, but rather is an indication
that effects may occur, especially in sensitive subpopulations. If the HQ is less than unity,
then the likelihood of adverse noncarcinogenic effects is small. The HQ for all contaminants
for a specific pathway or a scenario can be summed to provide a hazard index (HI) for that
pathway or scenario. RfD's are route specific. Currently, all of the RfD's in IRIS are based
on ingestion and inhalation; none have been based on dermal contact. Until more appropriate
dose-response factors are available, the oral RfD's should be used to evaluate dermal
exposures. The uncertainty regarding these assumptions is discussed below in the uncertainty
section.
Human Health Qualitative Risk Assessment The Human Health QRA provided estimates of
risk that might occur under residential or recreational use scenarios based on the best available
knowledge of current contaminant conditions. It does not represent actual risks since neither
residential or recreational use of high-priority sites currently occurs. Furthermore, potential
adverse effects of exposure to radionuclides factored in decay until the year 2018. Risk
characterization for the individual waste sites differs depending on the type and amount of data
available for the specific waste site. Risk characterization was conducted in accordance with
the Hanford Site Risk Assessment Methodology. The risk characterization for each site was
performed by calculating contaminant-specific ICR's and HQ's and then summing
contaminant-specific risks to obtain a risk estimate for the waste site. For sites where
sampling data was not available to calculate ICR's and HQ's, the risk characterization
consisted of a qualitative discussion of the site, the potential threat posed by the site, and the
confidence hi the information available to assess the threat. Risk estimates from analogous
sites were used, where appropriate, to qualitatively determine possible contaminants and
potential risk levels.
Under the residential scenario the QRA identified that the major human health risk (ICR > 1
x 10"2) was primarily associated with external exposure from the radionuclides Co-60, Cs-137,
Eu-152, Eu-154 and Sr-90. Under the recreational scenario, the QRA identified that the major
human health risk (ICR > 1 x 10*2) was primarily associated with external exposure from the
radionuclides Co-60, Cs-137, Eu-152, Eu-154 and Sr-90. Under the recreational scenario at
approximately one half of the sites, for the radionuclides Co-60, Cs-137, Eu-152, Eu-154, and
Sr-90 the ICR was greater than 1 x 10"2, the remaining sites the risk ranged from 2 x 10~3 to 3
x 10"6- At the 116-C-5 hexavalent chromium (Cr 6+) was associated with a an ICR of 2 x
10** for residential and 3 x 10* for recreational. At a limited number of sites, an HI of 2.0
was identified for chromium (Cr 6+) and Arsenic. OU-specific summaries are presented
below.
100-BC-l Based on the qualitative risk assessment, the contaminants in soils, structures, and
debris providing the highest contribution to potential increased cancer risks (ICR > 1 x 10"2)
included the radionuclides ^Co, 137Cs, l52Eu, and 154Eu, via external exposure. Chromium hi
soil provided the highest contribution to noncancer hazard indices at 100-BC-l Operable Unit
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sites. The risk estimates presented in Table 15 represent potential future risks if the area were
to be used for recreational or residential purposes. These risks are outside of EPA's
acceptable risk range and show that remedial actions should be taken at these sites.
100-DR-l Based on the qualitative risk assessment, the contaminants in soil providing the
highest contribution to potential increased cancer risks (ICR > 1 x 10"2) include the
radionuclides wCo, I37Cs, 152Eu, and >54Eu Chromium in soil provides the highest contribution
to noncancer hazard indices at 100-DR-l Operable Unit sites. The risk estimates presented in
Table 16 represent potential future risks if the area were to be used for recreational or
residential purposes. These risks are outside of EPA's acceptable risk range and show that
remedial actions should be taken at these sites.
100-HR-l Based on the qualitative risk assessment, the contaminants in soil providing the
highest contribution to potential increased cancer risks (ICR > 1 x 10"2) includes the
radionuclides ^Co, 137Cs, :52Eu, and 154Eu. Arsenic in soil provide the highest contribution to
noncancer hazard indices at 100-HR-l Operable Unit sites. The risk estimates presented in
Table 17 represent potential future risks if the area were to be used for recreational or
residential purposes. These risks are outside of EPA's acceptable risk range and show that
remedial actions should be taken at these sites.
Summary of Key Uncertainties in the Human Health Risk Assessment In general, the
QRA is based on a limited data set. Uncertainties are associated with both the contaminants
identified for each waste site and the concentrations of the contaminants. Collected samples
may not be representative of conditions throughout the waste site and historical data may not
accurately represent current conditions. Because the samples may not be completely
representative of the site, risks may be underestimated or overestimated.
External exposure slope factors are appropriate for a uniform contaminant distribution, infinite
in depth and areal extent (i.e., an infinite slab source), with no clean soil cover. For
high-energy gamma emitters (e.g., Co-60 and Cs-137), the assumption of an infinite slab
source can only be satisfied if these radionuclides extend to nearly 2 meters (6 ft) below
ground surface, and over a distance of a few hundred meters or more. If the site being
evaluated is smaller than this, or if the site has a clean soil cover, then use of external
exposure slope factors is likely to over-estimate potential risks. The fact that the external
exposure pathway is the risk-driver at many waste sites is not surprising and in some cases
may be indicative of the uncertainty built into the evaluation of this pathway rather than the
actual associated risk.
For non-carcinogenic chemicals, the reference doses (RfD) are used as benchmarks for toxic
endpoints of concern. RfD's are derived from data obtained from studies in animals or
humans using modification and uncertainty factors that account for uncertainty in the
information used to derive the RfD. Uncertainty factors are applied for extrapolation of the
no-observed-effects-level (NOEL) in a study population to the RfD used in the risk
assessment. A factor of 10 is usually applied to reflect the level of each of the sources of
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uncertainty listed below:
Use of lowest observed effect level (LOEL) or other parameters that are less
conservative than NOEL;
Use of data from short-term exposure studies to extrapolate to long-term
exposure;
• Use of data from animal studies to predict human effects; and
Use of data from homogeneous animal populations or healthy human
populations to predict effects in the general population.
A modifying factor (as published by EPA in IRIS or HEAST) may also be incorporated into
the RfD to reflect qualitative professional judgements regarding scientific uncertainties not-
considered by the uncertainty factor, such as the completeness of the data base and the number
of animals in the study.
Risk Assessment Sensitivity Analysis It is of note that the analyses presented in the main text
of the Process Document and the OU-Specific Focused Feasibility Studies assumed a future
base case of a recreational land use in the year 2018. Additional analyses were undertaken for
a limited number of sites to compare and contrast the impacts of other land uses and associated
potential risks. A future residential land use was evaluated in this manner within the
framework of the feasibility study.
That analysis indicated that groundwater usage under differing land use scenarios would be the
main component affecting differences in overall potential adverse risks. Furthermore, that
under differing land usage, exposure to soil contaminants posed very little changes in overall
potential adverse risks. Therefore, achieving a goal of unrestricted use of lands in the 100
Area, using a future residential scenario for soil exposure represents a minor, incrementally
more stringent remediation goal than die future base case recreational scenario.
An analysis also was undertaken to examine the impacts of evaluating potential risks under a
full set of exposure pathways (i.e. a complete baseline analysis instead of the subset analyzed
under the QRA). That analysis indicated that contaminant specific risks do not differ between
the full set and die subset of exposure pathways with die following exceptions. Under the
residential scenario, contaminant specific risks calculated for the full set of exposure pathways
are 3-fold greater for Sr-90 and Aroclor-1260; 7-fold greater for benzo(a)pyrene; and 4-fold
greater for chrysene and pentachlorophenol. Under die recreational scenario, these
contaminant specific risks calculated for die full set of exposure pathways are more than 2-fold
greater. The increased risks for Sr-90 is primarily attributable to die crop ingestion pathway.
The increased risks associated with organic contaminants is primarily attributable to the crop
ingestion and dermal contact with groundwater pathways. The increases would be of concern
for sites where Sr-90, Aroclor-1260, benzo(a)pyrene or chrysene were the primary
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contaminants of concern for remediation. For the remaining contaminants, the external
exposure or groundwater ingestion pathways are the primary pathways of concern. Those two
pathways are common to both the QRA pathway set and the full pathways set.
Ecological Qualitative Risk Assessment The purpose of the qualitative ecological risk
assessment is to estimate the ecological risks from existing contaminant concentrations in the
100 Area Operable Units to selected ecological receptors. Strontium 90 and Technetium 99
were found to pose potential elevated risk (EHQ > 1) to individual mice under the ecological
exposure scenario. The results of the qualitative ecological risk assessments for the OU's is
discussed below. Summary information on sites that exceed the EHQ is presented in Tables
15, 16, and 17.
The 100-BC-l, 100-DR-l and 100-HR-l Operable Units contain terrestrial waste sites. The
approach to the risk assessment that was taken was to assess the dose to the Great Basin pocket
mouse which was chosen as the indicator ecological receptor for potential adverse risk from
each of the waste sites within the 100 Area Operable Units. The mouse is used as the indicator
receptor because its home range is comparable to the size of most waste sites and will receive
most of its dose from a waste site. This allows a risk comparison between waste sites.
Contaminants found in the soil at waste sites within the 100 Area Operable Units include
radioactive and non-radioactive elements. For non-radioactive elements, ecological effects
were evaluated from uptake from the soil by plants, and by accumulation of these elements
through the foodweb. Radioactive elements have ecological effects resulting from their
presence hi the environment (external dose), and from ingestion (e.g., dose from contaminated
food consumption), resulting in a total body burden. Total daily doses to an organism can be
estimated as the sum of doses (weighted by energy of radiation) received from all radioactive
elements ingested, residing in the body, and available in the organism's environment.
The radiological dose an organism receives is usually expressed as rad/day. Exposure can
result from both external environmental radiation and internal radiation from body burden.
All exposure pathways are added in determining total organism dose. Internal exposure
includes both body burden (contaminants that are taken into the body from all pathways) and
dose from recent food consumption which is still in the gut. The assessment and measurement
endpoint is the health and mortality of the Great Basin pocket mouse. The dose to the pocket
mouse was used to screen the level of risk of an individual waste site. For radionuclides, the
dose to the mouse was compared to 1 rad/day (DOE Order 5400.5) (IAEA 1992). For
non-radiological contaminants, the dose was compared to toxicity values.
100-BC-l Nearly all of the radiological risk (EHQ > 1.0) to the mouse at this Operable Unit
was attributable to strontium-90. The inorganic contaminants that exceed an EHQ of 1.0
include antimony, chromium, and mercury.
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100-DR-l Nearly all of the radiological risk (EHQ > 1.0) to the mouse at this Operable
Unit was attributable to strontium-90. The inorganic contaminant chromium exceeded a EHQ
of 1.0.
100-HR-l Nearly all of the radiological risk (EHQ > 1.0) to the mouse at this Operable Unit
was attributable to strontium-90. The inorganic contaminants that exceed an EHQ of 1.0 at
the 116-H-7 Retention Basin include arsenic, lead, and zinc.
Summary of Key Uncertainties in the Ecological Evaluation A significant source of
uncertainty in the exposure scenario is that the waste site is uniformly contaminated and in the
case of the mouse, all food is assumed to be contaminated. It was also assumed contaminants
were not passed through the gut, but completely retained (100% absorption efficiency).
To complete the QRA for the 100 Area Operable Units it was necessary to use data from
surrogate organisms in place of the pocket mouse since no site data are available for this
organism. This contributes to overall QRA uncertainty. In addition, transfer coefficients used
to model uptake of contaminants from soil to plants were not Hanford specific, the approach
did not consider whether roots of a plant actually grow deep enough to contact a contaminant,
and the model did not account for reduced concentrations from plant to seed (it was assumed
the seed concentration was the same as the plant). The pocket mouse food consumption rate
was generalized and seasonal behavior (hibernation) that would reduce exposure and body
burden was not considered. Uncertainty associated with wildlife toxicity values is significant,
particularly for non-radiological contaminants. The approach used in the QRA tends to build
uncertainty into the toxicity value.
The estimated dose from Sr-90 to the Great Basin pocket mouse exceeded 1 rad/day from all
waste sites that had measurable Sr-90 at the 100-HR-l Operable Unit. The significance of dose
estimates, either radiological or hazardous chemicals, as the risk driver is governed by the
accuracy of the source terms. For example, if the source of Sr-90 is 6-15 ft below the surface,
the dose may not represent real ecological risk since the exposure scenario is very
conservative. The approach used in the QRA presented the maximum level of contamination
irrespective of depth (anywhere from 0-15 ft depth) which drives the QRA to conservative
conclusions.
Note: Potential adverse impacts to the Columbia River ecosystem were not specifically
addressed in the 100-BC-l, 100-DR-l and 100-HR-l evaluations. Rather, such impacts are
being evaluated through other activities such as the 100 Area groundwater studies and the
Columbia River Study. However, there are several source areas within the 100-BC-l, 100-DR-
1 and 100-HR-l OU's that have caused releases that have reached the groundwater and the
Columbia River at levels that exceed criteria for the protection of aquatic species. This is
most notably a concern for hexavalent chromium from source areas hi 100-DR-l,
100-FR-l andlOO-HR-1.
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VII. REMEDIAL ACTION OBJECTIVES
Remedial Action Objectives (RAO's) are site specific goals that define the extent of cleanup
necessary to achieve the specified level of remediation at the site. The RAO's are derived
from ARAR's, the points of compliance, and the restoration timeframe for the remedial action.
The RAO's were formulated to meet the overall goal of CERCLA, which is to provide
protection to overall human health and the environment.
Contaminants of concern were identified based on a statistical and risk-based screening
process for affected media. The potential for adverse effects to human health and the
environment were initially identified in the LFI report, and were further evaluated in the QRA.
Findings of these assessments are summarized in the previous section.
Land Use. A key component in the identification of RAO's is the determination of current
and potential future land use at the site. These long range land use assumptions are not
predictors of long-term land use (beyond 20 to 30 years) and should not be used as predictors
of land use beyond reasonable lengths of time, nor for land use changes resulting from longer
term events. The Hanford Future Site Users Working Group (the Working Group) was
convened hi April of 1992 to develop recommendations concerning the potential use of lands
after cleanup. The Working Group issued their report in December 1992 and proposed that
the cleanup options at the 100 Area be based on eventual unrestricted land use. The final land
use of the 100 Area has not been established. Remedial action objectives and cleanup goals
will be re-evaluated if future land use and groundwater use determinations are inconsistent
with the goals presented hi this ROD.
Factors that were considered in conjunction with the Working Group proposals include: (1)
that contaminated sites which would exist indefinitely (beyond any reasonable tune for assured
institutional control) would be cleaned up for unrestricted use where practicable, and (2) that
institutional controls (such as land and groundwater restrictions) be implemented for sites
associated with low risks where it can be shown that the contaminant would degrade or
attenuate within a reasonable period of time or, for sites where contaminants would remain in
place above unrestricted use cleanup goals, where it can be shown that meeting the more
stringent cleanup goal is not practicable. For the 100 Area, a reasonable period of time was
identified by the Working Group as "as soon as possible (by 2018)". This time frame
coincides with the TriParty Agreement date for completion of cleanup actions in the 100 Area.
Chemicals and Media of Concern. Risks from soil and groundwater contaminants of concern
were identified at levels that exceed the EPA risk threshold and may pose a potential threat to
human health. The NCP requires that the overall incremental cancer risk (ICR) at a site not
exceed the range of 1 x lO"6 to 1 x 104. The State of Washington's Model Toxics Control Act
(MTCA) is' more stringent and requires that this risk not exceed 1 x 10"6 to 1 x lQrs. For
systemic toxicants or noncarcinogenic contaminants, acceptable exposure levels shall represent
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levels to which the human population may be exposed without adverse effect during a lifetime
or part of a lifetime. This is represented by a hazard index (HI). For sites in the state of
Washington where the cumulative carcinogenic site risk to an individual based on reasonable
maximum exposure for both current and future land use is less than 1 x 10-5, and the
noncarcinogenic HI is less than 1, action generally is not warranted unless there are adverse
environmental impacts or other considerations, such as exceedances of MCL's or nonzero
MCLG's. Risks associated with 100 Area Operable Units waste site contaminants are
summarized in Tables 14, 15, and 16 in Section VI.
Remedial Action Objectives. RAO's have been identified for the contaminated near surface
and subsurface soils, structures, and debris at the 100 Area Operable Units waste site for this
interim action, as well as for 100 Area groundwater and the Columbia River. The ROA's and
the principal requirements for achievement of them are discussed in the following paragraphs.
The interim remedial action selected by this document has the following specific remedial
action objectives:
1. Protect human and ecological receptors from exposure to contaminants in soils, structures,
and debris by dermal exposure, inhalation, or ingestion of radionuclides, inorganics or
organics.
This RAO will be achieved through excavation to State of Washington Model Toxics Control
Act (MTCA) levels for organic and inorganic chemical constituents in soil to support
unrestricted (residential) use, and the draft EPA and the draft Nuclear Regulatory Commission
proposed protection of human health standards of 15 mrem/year in soils above background for
radionuclides. For interim remedial actions that leave any contaminant in place above MTCA
levels, and/or the proposed draft EPA and draft NRC guidance for remediation of soils for
radionuclides, adequate institutional controls will be required to monitor the site after
remediation and to prevent potential future receptor exposure to contaminants.
2. Control the sources of groundwater contamination to minimize the impacts to groundwater
resources, protect the Columbia River from further adverse impacts, and reduce the degree of
groundwater cleanup that may be required under future actions.
This RAO will be achieved by protection of groundwater that has not been impacted such that
contaminants remaining in the soil after remediation do not result in an adverse impact to
groundwater that could exceed Maximum Contaminant Levels (MCL's) and non-zero MCLG's
under the Safe Drinking Water Act (SDWA). The SDWA MCL for radionuclides will be
attained at a designated point of compliance beneath or adjacent to the waste site hi
groundwater. The location and measurement of the point of compliance is to be defined by
EPA and Ecology. Monitoring for compliance will be performed at the defined point.
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Another consideration for achievement of this RAO is protection of the Columbia River such
that contaminants remaining in the soil after remediation do not result in an impact to
groundwater and, therefore, the Columbia River that could exceed the Ambient Water Quality
Criteria (AWQC) under the Clean Water Act for protection of fish. Since there are no AWQC
for radionuclides, MCL's will be used. The protection of receptors (aquatic species, with
emphasis on salmon) in surface waters will be achieved by reducing or eliminating further
contaminant loadings to groundwater such that receptors at the groundwater discharge in the
Columbia River are not subject to any additional adverse risks. Measurement of compliance
will be at a nearshore well, in the downgradient plume. The location and measurement will be
defined by EPA and Ecology.
3. To the extent practicable, return soil concentrations to levels that allow for unlimited future
use and exposure. Where it is not practicable to remediate to levels that will allow for
unrestricted use in all areas, institutional controls and long-term monitoring will be required.
For deep sites, such as the 116-B-l Process Effluent Trench, the 116-D-2B Crib and the 116-
H-7 Retention Basin where contamination begins at a depth at least 15 feet below the surface,
Several factors will be considered in determining the extent of remediation including reduction
of risk by decay of short-lived (half life of less than 30.2 years) radionuclides, protection of
human health and the environment, remediation costs, sizing of the Environmental Restoration
Disposal Facility, worker safety, presence of ecological and cultural resources, the use of
institutional controls, and long term monitoring costs. In the event that an evaluation is being
considered that could allow for contaminated soil to be left in place, additional public comment
will be requested and an Explanation of Significant Differences published. Long-term
groundwater monitoring also will be required. The application of the criteria for the balancing
factors, the process for determining the extent of remediation at deep sites, and the public
involvement process during such determinations shall be specified further in the Remedial
Design Report.
Residual Risks Post-Achievement of RAO's. Residual risks after meeting RAO's were
estimated based on a residential land use scenario for soils. Site risks from contaminated soils,
structures, and debris with respect to metals and organics are reduced from greater than
1 x 10'2 to approximately 1 x 10"6, representing a 99.999 percent reduction in risk. Site risks
from contaminated soils, structures, and debris with respect to radionuclides are reduced from
greater than 1 x 10"2 to approximately 3 x 10"*, representing a 99.66 percent reduction in risk.
Remediation Timeframe. Pursuant to CERCLA section 120 (e)(2) substantial onsite physical
remedial action at waste sites in the 100-BC-l, 100-DR-l and 100-HR-l OU's will commence
no later than 15 months after the issuance of this ROD. Waste site prioritization will occur in
the Remedial Design/Remedial Action phase. The expectation is to address those sites which
are contributing chromium contamination to groundwater, which hi turn impacts the Columbia
River. Completion of these actions shall be consistent with the overall goal of completion of
100 Area remedial actions by the year 2018. The Remedial Design Report and Remedial
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Action Work Plan for the implementation of this ROD shall include a comprehensive
implementation schedule to achieve RAO's for the 37 waste sites addressed in this ROD.
Tables 18, 19 and 20 from the OU-specific FFS reports present waste site specific remediation
timeframes. These are discussed further in Section IX, and can be found at the end of that
section.
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VHI. DESCRIPTION OF ALTERNATIVES
The 100 Area Source Operable Unit Focused Feasibility Study (DOE/RL-94-61) identified six
general response actions that could be applied to waste sites in the 100 Areas, including the
100-BC-l, 100-DR-l and 100-HR-l Operable Units. The alternatives evaluated for interim
remediation are as follows:
• No action
• Institutional Controls
• Containment
In Situ Treatment
• Remove/Dispose
• Remove/Treat/Dispose.
Note: The No Action, Institutional Controls, Containment and-In Situ Treatment alternatives
would limit the future uses of the 100 Area. A stated goal of the remediation of the 100 Area is
to allow for unrestricted use of the 100 Area lands.
No Action. Evaluation of this alternative is required under CERCLA; it serves as a reference
against which other alternatives can be compared. Under this alternative, no action would be
taken to remove, treat, or contain contamination at this site and no institutional controls would
be established to prevent exposure. There is no cost associated with this alternative.
Institutional Controls - This alternative involves the following:
* deed and/or access restrictions
groundwater monitoring.
Deed restrictions would consist of limitations on certain types of land-uses (e.g., prohibiting
drilling or excavation) at an individual waste site. Access restrictions would include fences or
signs. Groundwater monitoring would include sampling for potential changes in groundwater
contaminant concentrations underlying the waste sites. These institutional controls would limit
exposure to humans and would monitor changes in groundwater quality until a final response
action could be evaluated and implemented.
Containment - This alternative includes the following elements:
institutional controls
• groundwater monitoring
• surface water controls
installation of a surface barrier at the surface.
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As described under the institutional control alternative, deed restrictions and/or access
restrictions, combined with groundwater monitoring, would be implemented along with
surface water controls during and after installation of a surface barrier, such as the Hanford
Barrier.
In Situ Treatment (for soil) - This alternative applies to contaminated soil and includes the
following elements:
institutional controls
• groundwater monitoring
• surface water controls
• in situ vitrification.
Institutional controls such as deed restrictions and/or access restrictions, groundwater
monitoring, and surface water controls would be implemented as discussed under the
institutional control and containment alternatives after completion of the in situ vitrification
process. Under this alternative, the contaminated soil would be vitrified in place and covered
with a minimum of one meter of soil. The disturbed area would then be revegetated.
In Situ Treatment (for Buried Process Effluent Pipelines) - This alternative applies to
buried process effluent pipelines and contaminated soils. It includes the following elements:
institutional controls
• groundwater monitoring
• void grouting
. installation of a surface barrier, if needed.
Under this alternative, deed and/or access restrictions, groundwater monitoring, and surface
water controls would be implemented as previously described. The buried process effluent
pipelines would be pressure injected in place with grout that would immobilize contamination
in the pipeline (i.e., the contaminated metal, scale, and sediments in the pipe) through
encapsulation. A surface barrier would be installed (as described in the containment
alternative) over soils and buried pipelines if needed to reduce infiltration of rainwater.
Remove/Dispose - This alternative applies to contaminated soils and structures and includes
the following:
• remove contaminated soils, structures, and debris
• dispose contaminated materials at an approved disposal facility
• backfill of excavated areas and revegetation.
Under this alternative, contaminated media would be excavated, transported, and disposed at
the Environmental Restoration Disposal Facility, in accordance with waste acceptance criteria
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established for the disposal facility. A draft of the waste acceptance criteria was released in
June, 1995, and a final is expected in October of 1995. This timeframe will coincide with the
early development of the remedial design activities. Any material that exceeds the disposal
facility acceptance criteria would be stored onsite consistent with requirements until treated to
meet acceptance criteria or a treatability variance is approved. As the contaminated material is
excavated, it would be characterized and segregated prior to transportation. Excavation would
continue until all contaminated material exceeding the cleanup goal is removed. The site
would then be backfilled with clean material and the area would be revegetated. Site specific
revegetation plans will be developed during remedial design with input from affected
stakeholders including Natural Resource Trustees and Native American Tribes.
Remove/Treat/Dispose - This alternative applies to sites with contaminated soil and
structures, and includes the following elements:
• remove contaminated soils, structures, and debris
thermal desorption, if required, for soil
soil washing, as appropriate
dispose contaminate materials at an approved facility
• backfill of excavated areas and revegetation.
Under this alternative, the contaminated soils would be excavated as described under the
remove/dispose alternative. Soils contaminated with organic chemicals at levels exceeding
waste disposal acceptance criteria would be treated (e.g. thermal desorption), as necessary to
meet acceptance criteria. It may be then recombined with the remaining contaminated soils
prior to soil washing.
Soil washing could reduce the volume of contaminated soil for disposal. The application of
soil washing to a waste site will depend on several factors including soil conditions,
contaminant specific cleanup goals and the level of contaminants present. Soil washing is a
desirable treatment only when significant volume reduction can be achieved. It would only be
performed when such volume reduction could be achieved in a cost-effective manner. The
greatest cost benefit would be achieved at large volume sites with low levels of contaminants.
Treatability studies have been completed to evaluate the applicability of soil washing in the
100 Areas. A final report on the applicability of soil washing in the 100 Area that includes
presentation of key parameters to determine the cost effectiveness of the soil washing step is
expected to be released in September, 1995. That information, together with site specific
determinations during remedial design and remedial action activities will be relied upon to
make waste site specific determinations on the appropriateness of the soil washing step.
Following removal and treatment, contaminated soil and/or contaminated products resulting
from treatment technologies would be disposed of in the same manner as the remove/dispose
alternative. The excavation would be backfilled with washed soils and other soils as needed
and revegetated.
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IX. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
This section summarizes the relative performance of each of the alternatives with respect to the
nine criteria identified in the NCP. These criteria fall into three categories: The first two
(Overall Protection of Human Health and the Environment and Compliance with ARAR's) are
considered threshold criteria and must be met. The next five are considered balancing criteria
and are used to compare technical and cost aspects of alternatives. The final two criteria (State
and Community Acceptance) are considered modifying criteria. Modifications to remedial
actions may be made based upon state and local comments and concerns. These were
evaluated after all public comments were received.
The discussion presented below is general hi nature, rather than OU or site specific, due to the
large number of waste sites in the three OU's and the similarity in characteristics.
Overall Protection of Human Health and the Environment Overall Protection of Human
Health and the Environment addresses whether or not a remedy provides adequate protection
and describes how risks posed through each pathway are eliminated, reduced, or controlled
through treatment, engineering controls, or institutional controls.
The no action alternative does not meet this criteria. Institutional controls alone cannot be
relied on to indefinitely provide protection, and therefore does not meet this criteria. The
containment alternative would provide protection by encapsulating wastes for the pipelines, but
would not provide adequate protection for the retention basin and trenches. The in situ
alternative would provide overall protection for the retention basins and pipelines, but would
not adequately address the effluent trenches. The remove/dispose and remove/treat/dispose
alternatives would provide overall protection of human health and the environment.
Compliance with ARAR's Compliance with ARAR's addresses whether a remedy will meet
all of the applicable or relevant and appropriate requirements (ARAR's) of other Federal and
State environmental laws and/or justifies a waiver.
The no action, institutional controls, containment and in-situ treatment alternatives would not
meet all of the principal ARAR's identified for all of the sites. The remove/dispose and the
remove/treat/dispose alternatives would meet the ARAR's. If Land Disposal Restricted
contaminants are encountered, contaminated soil would be treated or a treatability variance
could be requested. No ARAR waivers have been requested or are being considered at this
time. In the event that technical ^feasibility or other ARAR waiver criteria are demonstrated
that meet EPA and Ecology requirements, in a timely manner, the TriParties will evaluate the
need for an ARAR waiver. If a waiver is requested, an Explanation of Significant Differences
will be issued and the public will be provided an opportunity to comment.
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Long-Term Effectiveness and Permanence Long-Term Effectiveness and Permanence refers
to the magnitude of 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.
The no action and institutional controls alternatives would not meet cleanup goals and,
therefore, would not provide for long-term effectiveness. Containment and in-situ treatment
would provide a greater degree of long term effectiveness by stabilizing and isolating the
wastes in place. The remove/dispose and remove/treat/dispose alternatives would provide the
greatest long-term effectiveness and permanence by containing and isolating wastes further
away from affected groundwater and the Columbia River at the ERDF.
Reduction of Toxicity, Mobility, or Volume through Treatment or Recycling Reduction of
Toxicity, Mobility, or Volume through treatment is the anticipated performance of the
treatment technologies that may be employed in a remedy.
The no action and institutional controls alternatives do not reduce the mobility, toxiciry, or
volume of the contaminants. The containment and institutional controls alternatives do not
include treatment. The containment, in-situ treatment, and remove/dispose alternatives would
reduce the mobility of contaminants but not the volume or toxiciry of most contaminants (ISV
would permanently destroy some organics). The remove/treat/dispose alternative provides the
most significant level of treatment and would reduce volume and mobility.
Short-Term Effectiveness Short-Term Effectiveness refers to the speed with which the
remedy achieves protection, as well as the potential of the remedy to create adverse impacts on
human health and the environment during the construction and implementation period.
The no action and institutional controls alternatives require minimal effort to implement. The
containment and in-situ treatment options require technology that is readily available. The
remove/dispose alternative would provide a greater degree of short-term protectiveness than
the remove/treat/dispose alternative because it requires less time to implement, utilizes
standard technologies, and presents less short-term risk to workers and the environment.
Implementability Implementability is the technical and administrative feasibility of a remedy,
including the availability of materials and services needed to implement the solution.
The institutional controls alternative would require administrative actions such as deed
restrictions. The containment and in situ treatment alternatives are implementable with existing
technologies. The remove/dispose alternative is easier to implement than the
remove/treat/dispose alternative since no treatment step is required. The treatment steps
evaluated under the remove/treat/dispose alternative utilize existing technologies that have
been routinely applied under full scale conditions at numerous hazardous waste sites.
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Remediation timeframes for specific waste sites in 100-BC-l, 100-DR-l and 100-HR-l from
the OU-specific FFS reports are presented in Tables 18, 19, and 20, respectively. For the
individual waste sites, the timeframes range from approximately one month to 8.1 years (insitu
treatment at 116-H-7 retention basin). Totals for the alternatives (which are not applicable to
all sites) are; containment - 5.3 years; insitu treatment -19.5 years; remove/dispose -11.3
years; and remove/treat/dispose -15.5 years. This total is representative of the expected
duration if the sites were remediated sequentially, one at a time. Significant time and cost
savings would be realized through mobilization and remediation of multiple sites, and multiple
OU's concurrently.
Cost Cost includes capital and operation and maintenance costs. The estimated costs are
present worth costs (capital costs plus annual costs over the life of the project, with a 5%
discount rate). Preliminary cost estimates were developed as part of the Phase 3 Source
Focused Feasibility Study (The Process Document) and extrapolated to operable unit specific
waste sites. Those estimates were based on conservative assumptions that tend to overestimate
actual costs of remediation. Expedited Response Actions (ERA) initiated at waste sites in the
100-BC-l Operable Unit during July and August of 1995 are expected to result in a more
accurate development of costs. The costs presented in the summary tables of this ROD are
those that were developed and presented in the FFS reports. Tables 17, 18, and 19 present the
summary information on the preliminary cost estimates. These estimates should be considered
useful only for relative comparison of alternatives. The total preliminary costs associated with
the selected interim action is $475.8M for the 27 waste sites evaluated in the OU-specific FFS
reports. The preliminary cost estimates for the 10 additional waste sites based on an
analogous site type approach is S15.2M.
As discussed in previous sections, assumptions on volumes of contaminated media for
remediation are very conservative and likely to be significantly over-estimated. Additional
analyses by EPA and Ecology also indicated conservative inputs to the cost estimating model
software (MCASES) such as sampling and analysis costs, disposal fees and administrative
costs that will need to be reviewed during remedial design prior to development of the
government estimate for cost realism and to identify areas where value engineering can
provide additional cost savings.
Based on initial results from the 100-BC-l ERA, it is expected that significantly lower costs
will be associated with remediation of the 100 Area waste sites. Approximately $241.7M of
the preliminary cost (approximately 51 % of the total) is for remediation of the six sites
identified as potential candidates for leaving some level of wastes in place above the cleanup
goals for unrestricted use. In the event that such a decision is made during remedial design
and remedial action activities, the costs associated with those six sites will be significantly
lower.
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State Acceptance State Acceptance indicates whether, based on its review of the Final LFI,
QRA and FFS Reports, Proposed Plans, and Administrative Record, the State concurs with,
opposes, or has no comment on the preferred alternative.
For the 100-DR-l and the 100-HR-l the Washington State Department of Ecology is the lead
regulatory agency. The redesignation of waste sites under this action from RPP to CPP does
not affect the lead regulatory agency status of Ecology. Ecology has been involved with the
development and review of the Remedial Investigation, Feasibility Study, Proposed Plan, and
Record of Decision. Ecology comments have resulted in significant changes to these
documents and has been integrally involved in determining which cleanup standards apply
under MTCA.
The State of Washington concurs with the selection of the interim remedial actions described
in this ROD.
Community Acceptance Community Acceptance refers to the public's support for the
preferred remedial alternative and is assessed following a review of the public comments
received on the Final LFI, QRA and FFS Reports and the Proposed Plans for the Operable
Units.
On July 25, 1995, a public meeting was held to discuss the Proposed Plans for the 100-BC-l,
100-DR-l and 100-HR-l Operable Units. The results of the public meeting and the public
comment period indicates acceptance of the preferred remedial alternative. Community
response to the remedial alternatives is presented hi the responsiveness summary, which
addresses questions and comments received during the public comment period.
34
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X. SELECTED REMEDY
The components of the selected remedy achieve the best balance of the nine evaluation criteria
described above. The total preliminary estimated cost of the remedy is S491M. The
preliminary design considerations described hi this ROD are for cost estimating and are
expected to change significantly based on the final remedial design and construction practices.
As noted under the comparative analysis section of this ROD, actual costs of remediation are
expected to be significantly lower than the preliminary cost estimate.
The selected remedy for high priority liquid radioactive effluent disposal sites will include, at
a minimum, the following activities.
1. Per the TriParty Agreement, DOE is required to submit the Remedial Design Report,
Remedial Action Work Plan, and Operations and Maintenance Plan for treatment units as
primary documents. These documents and associated documents concerning the planning and
implementation of remedial design and remedial action shall be submitted to EPA and Ecology
for approval prior to the initiation of remediation.
2. Removal and stockpiling of any necessary uncontaminated overburden. To the extent
practicable, this material will be used for backfilling of excavated areas.
3. Excavation and transportation of contaminated soils, structures and debris to the ERDF for
disposal. Excavation activities will follow all appropriate construction practices for excavation
and transportation of hazardous materials, and will follow ALARA practices for remediation
workers. Dust suppression during excavation, transportation, and disposal will be required, as
necessary.
4. Treatment, as appropriate, for volume reduction through soil washing, or through thermal
desorption will be performed in the 100 Area, and prior to transportation to the ERDF for
disposal. The intent of treatment of soils, structures, and debris is to minimize the amount of
material to be transported to the ERDF for disposal. Recycling of treated materials and re-use
of treated materials for backfilling of excavated areas also is expected to reduce remedial
action costs. Materials that are transported to ERDF for disposal must meet the disposal
acceptance criteria, including treatment provisions, for that facility.
5. The measurement of contaminant levels during remediation will primarily rely on field
screening methods. Limited confirmational sampling of field screen measurements will be
undertaken to correlate and validate the field screening. Once field screening activities have
indicated that cleanup levels have been achieved, a more extensive confirmational sampling
program will be undertaken that routinely achieves higher levels of quality assurance and
quality control that will support the issuance of a CERCLA closeout report for the waste site.
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6. As discussed in previous sections, the extent of remediation of the waste sites will take into
account certain site-specific factors. The waste sites are represented by the following three
general categories and the primary factors for consideration are discussed for each.
a) For shallow sites where the entire engineered structure, soil or debris contamination is
present within the top 15 feet, RAO's will be achieved when contaminant levels are
demonstrated to be at or below MTCA levels for inorganics and organics for residential
exposure and the 15 mrem/year residential dose level, and are at levels that provide protection
of ground water and the Columbia River.
b) For sites where the engineered structure and/or contaminated soil and debris begins above
15 feet and extends to below 15 feet, the engineered structure, at a minimum will be
remediated to achieve RAO's such that contaminant levels are demonstrated to be at or below
MTCA levels for metals and organics for exposure and the 15 mrem/year residential dose
level, and are at levels that provide protection of groundwater and the Columbia River. Any
residual contamination present below the engineered structure shall be subject to the same
evaluation as for deep sites described in c) below.
c) For deep sites where contamination begins at a depth at least 15 feet below the surface,
several factors will be considered in determining the extent of remediation including reduction
of risk by decay of short-lived (half life of less than 30.2 years) radionuclides [Table 24
presents a summary of the radioactive half life for radionuclides present at Hanford],
protection of human health and the environment, remediation costs, sizing of the
Environmental Restoration Disposal Facility, worker safety, presence of ecological and
cultural resources, the use of institutional controls, and long term monitoring costs. The
extent of remediation also will have to ensure that contaminant levels are at or below MCL's
for protection of groundwater or AWQC for protection of the Columbia River. The application
of the criteria for the balancing factors, die process for determining the extent of remediation
at deep sites, and the public involvement process during such determinations shall be specified
further in the Remedial Design Report.
NOTE: The practice of placing clean fill over site to reduce exposure to radioactive
contaminants has resulted in many of the sites, such as trenches, being backfilled, and shallow
near surface sites receiving additional clean fill above them. When considering the top 15
feet, such past practices should not be taken into account, rather the grade at the time of
disposal will be considered as the ground surface.
7. Once a site has been demonstrated to have achieved cleanup levels and ROA's, it will be
backfilled with clean materials and revegetated in accordance with approved plans.
Revegetation plans will be developed as part of remedial design activities with input from
affected stakeholders such as Natural Resource Trustees and Native American Tribes.
Revegetation efforts will attempt to establish a viable habitat at the remediated areas and will
emphasize the use of native seed stock.
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8. Institutional controls and long-term monitoring will be required for any sites where wastes
are left in place that preclude unrestricted use. This is principally of concern for the limited
number of deep sites that satisfy 6 (c) above. DOE will control access and use of the site for
the duration of the cleanup, including restrictions on the drilling of new ground water wells in
the existing plumes or their paths. It is expected that institutional controls will be enforced
until the remedial action objectives have been attained. DOE shall submit a monitoring plan
to EPA and Ecology for approval as part of the documents described under (1) above. The
monitoring plan shall include provisions to meet all requirements of this ROD, monitoring
methods, schedules, documentation and tracking, methods of analysis, a timeframe for
continuing monitoring after cleanup performance requirements have been met (if applicable),
and a provision for evaluating the resumption of remedial action if post-cleanup monitoring
reveals levels that exceed cleanup standards as defined by this ROD. The monitoring plan
shall also include a reporting procedure to notify EPA and Ecology when cleanup performance
requirements have been met, with allowance for EPA and Ecology to verify analysis.
Monitoring plans and programs may be subject to other requirements based on federal or state
regulations or guidance.
9. Since this is an interim action and wastes will continue to be present in the 100 Area until
such time as a final record of decision is issued and final remediation objectives are achieved,
a five year review will be required.
10. The selected remedy relies on the Plug-In Approach for determining sites to be candidates
for an IRM and the Observational Approach to remediation for implementation of the IRM.
Both of these are discussed in greater detail below.
The Observational Approach and the Plug-in Remedy Approach. The 100 Area of the
Hanford Site is complex and contains many individual waste sites within the area. Based on
the circumstances presented by the 100 Area, the use of two innovative approaches to
remediation of the sites will enhance the efficiency of the selected remedy. The approaches
are the "Observational Approach" and the "Plug-in Approach".
The Observational Approach combines information from historical process operations (for this
action this is primarily historical liquid effluent discharges), information from limited field
investigations on the nature and extent of contamination, along with a "characterize and
remediate in one step" methodology. The latter consists of site excavation and field screening
for contaminants at sites where the remedial action has been selected. The observational
approach has been utilized in many areas within Hanford to implement streamlining activities
to focus resources towards early remediation in lieu of extended investigation of sites.
The Plug-in Approach allows for the selection of die same remedy at multiple, similar or
"analogous" sites. In the 100 Area, all of the reactor operations, except those hi N Area, were
virtually identical, leading to very similar releases of contaminants. Therefore, the Plug-in
Approach allows for the selection and application of the same remedy at similar sites at
37
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different reactor locations within the 100 Area where sufficient risk has been demonstrated
either through the limited field investigation and qualitative risk assessment, by the results of
previous historical sampling, and/or by an analogous site type approach where multiple,
similar sites that received similar discharges and are assumed to have similar levels of risks.
Under this approach, a standard remedy is selected that applies to a given set of circumstances,
rather than to a specific waste site. The sites will be both characterized and remediated, if
required, after the ROD. This approach allows the TriParties to select and implement a
remedial action at similar waste sites without expending resources to further characterize
multiple, similar sites across the 100 Area. This will also allow resources to be focused more
on remediation of waste sites.
In addition, if a site or sites exhibit conditions that would make one of the treatment options
(e.g. soil washing, thermal desorption) a viable enhancement to the selected remedy, the
application of the appropriate treatment step for volume reduction, and/or to meet ERDF
acceptance criteria, would be undertaken. In the event that technical infeasibility, or other
ARAR waiver criteria are demonstrated that meet EPA and Ecology requirements, in a timely
manner, the TriParties will evaluate the need for an ARAR waiver. In the event that some
materials cannot be disposed of at the ERDF, and require disposal at an offsite facility, such
an offsite facility must be in compliance with EPA's Offsite Rule (40 CFR 300) concerning
offsite disposal of wastes.
CERCLA Section 104(d)(4) states where two or more non-contiguous facilities are reasonably
related on the basis of geography, or on the basis of the threat or potential threat to the public
health or welfare or the environment, the President may, at his discretion, treat these facilities
as one for the purposes of this section.
The preamble to the NCP clarifies the stated EPA interpretation that when non-contiguous
facilities are reasonably close to one another and wastes at these sites are compatible for a
selected treatment or disposal approach, CERCLA Section 104(d)(4) allows the lead agency to
treat these related facilities as one site for response purposes and, therefore, allows the lead
agency to manage waste transferred between such non-contiguous facilities without having to
obtain a permit. Therefore, the 100 Area NPL site and the ERDF are considered to be a
single site for response purposes under this ROD. This is consistent with the determination
made in the January 20, 1995 ROD for the ERDF that stated... "Therefore, the ERDF and the
100, 200, and 300 Area NPL sites are considered to be a single site for response purposes
under this ROD."
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XI. STATUTORY DETERMINATIONS
Under CERCLA Section 121, selected remedies must be protective of human health and the
environment, comply with ARAR's, be cost effective, and utilize permanent solutions and
alternative treatment technologies or resource recovery technologies to the maximum extent
practical. In addition, CERCLA includes a preference for remedies that employ treatment that
significantly and permanently reduces the volume, toxicity, or mobility of hazardous wastes as
their principal element. This section discusses how the selected remedy meets these statutory
requirements.
Protection of Human Health and the Environment The selected remedy protects human
health and the environment through interim remedial actions to reduce or eliminate risks
associated with exposure to contaminated soils, structures, and debris. Implementation of this
remedial action will not pose unacceptable short-term risks toward site workers that cannot be
mitigated through acceptable remediation practices. Removal of contaminated soil, structures,
and debris will prevent exposure under future land use.
The qualitative risk assessment for a residential scenario associated with radionuclides at waste
sites under this interim action estimated risks greater than 1 x 10'2. The qualitative risk
assessment for a recreational scenario associated with radionuclides at waste sites under this
action also estimated risks greater than 1 x IQr2. Remediation of sites will principally occur to
remove radioactive contaminated soils, structures, and debris. The incremental residual risks
after implementation this remedy is estimated at 3 x 10^ (residential scenario) for exposure to
radionuclides. It is expected that decay of radionuclides will achieve the MTCA cumulative
risk level of 1 x 10"s and EPA's acceptable risk range of 1 x 10~* to 1 x 10^ through no more
than five successive half life decays. For inorganics and organics the residual risk is expected
to be 1 x 10^ or lower. It is expected that inorganics and organics, due to co-location with
radionuclides, will be remediated to levels at or below MTCA levels during the course of
implementation of the interim remedial actions.
Compliance with ARAR's The selected remedy will comply with the federal and state
ARAR's identified below. No waiver of any ARAR is being sought. The ARAR's identified
for the 100 Area Source Operable Units are the following:
Chemical-Specific ARAR's
• Safe Drinking Water Act (SDWA), 40 USC Section 300, Maximum Contaminant
Levels (MCL's) for public drinking water supplies are relevant and appropriate for
establishing cleanup goals that are protective of groundwater.
• Model Toxics Control Act Cleanup Regulations (MTCA), Chapter 173-340 WAC,
risk-based cleanup levels are applicable for establishing cleanup levels for soil,
structures and debris.
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• Clean Water Act, 33 USC Section 1251, for Protection of Aquatic Life are relevant
and appropriate for establishing cleanup goals thai are protective of the Columbia
River.
• Water Quality Standards for Waters of the State of Washington, Chapter 173-201-
035 WAC are applicable for establishing cleanup goals that are protective of the
Columbia River.
• National Primary and Secondary Ambient Air Quality Standards, 40 CFR Part 50,
are applicable due to potential airborne emissions of particulates or lead during
excavation, treatment, transportation or disposal of hazardous materials.
• National Emission Standards for Hazardous Air Pollutants, 40 CFR part 61, are
applicable for radionuclide emissions from facilities owned and operated by DOE.
Radionuclides are presented in the contaminated soils, structures and debris that
will be excavated, treated, transported and disposed under this interim action.
Action-Specific ARAR's
• Model Toxics Control Act Cleanup Regulations (MTCA), Chapter 173-340 WAC,
• State of Washington Dangerous Waste Regulations, Chapter 173-303 WAC are
applicable for the identification, treatment, storage, and land disposal of hazardous
and dangerous wastes.
• RCRA Subtitle C (40 CFR 261, 264, 268) are applicable for the identification,
treatment, storage, and land disposal of hazardous wastes.
• U.S. Department of Transportation Requirements for the Transportation of
Hazardous Materials (49 CFR Parts 100 to 179) will be applicable for any wastes
mat are transported off site.
• Hazardous Materials Transportation Act (49 USC 1801-1813), is applicable for
transportation of potentially hazardous materials, including samples and wastes.
• RCRA Land Disposal Restrictions (40 CFR 268) may be applicable for disposal of
inorganics or organics contaminated materials that are hazardous or dangerous
wastes to meet ERDF waste acceptance criteria.
• Minimum Standards for Construction and Maintenance of Wells (Chapter 173-160
and 162 WAC) Applicable regulations for the location, design, construction, and
abandonment of water supply and resource protection wells.
40
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• RCRA Standards for Miscellaneous Treatment Units (40 CFR 264 Subpart X). The
substantive requirements of this are relevant and appropriate to the construction,
operation, maintenance and closure of any miscellaneous treatment unit (e.g.
thermal desorption unit) constructed in the 100 Area for treatment of hazardous
wastes.
• RCRA Standards for Tank Systems Units (40 CFR 264 Subpart J). The substantive
requirements of this are relevant and appropriate to the construction, operation,
maintenance and closure of any tank units associated with soil washing treatment
units constructed in the 100 Area for treatment of hazardous wastes.
• State of Washington, Department of Health WAC 246, 247 is applicable to the
release of airborne radionuclides.
Location-Specific ARAR's
• National Archeological and Historical Preservation Act (16 USC Section 469); 36
CFR Part 65, is relevant and appropriate to recover and preserve artifacts in areas
where an action may cause irreparable harm, loss, or destruction of significant
artifacts.
• National Historic Preservation Act (16 USC 470, et. seq.)\ 36 CFR Part 800, is
relevant and appropriate to actions in order to preserve historic properties
controlled by a federal agency.
• Endangered Species Act of 1973 (16 USC 1531, et. seq.); 50 CFR Part 200; 50
CFR 402, is relevant and appropriate to conserve critical habitat upon which
endangered or threatened species depend. Consultation with the Department of the
Interior is required.
Other Criteria, Advisories, or Guidance to be Considered for this Remedial Action
(TBC's)
• 40 CFR Part 196. Draft Proposed Rulemaking by EPA for cleanup of
radionuclides in soils to 15mrem/year above natural background.
• 10 CFR Part 20. Draft Proposed Rulemaking by NRC for cleanup of radionuclides
in soils to 15mrem/year above natural background, and a goal of 3 mrem/year.
• Draft Environmental Restoration Disposal facility Waste Acceptance Criteria (June
1995) that delineates primary requirements including regulatory requirements,
41
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specific isotopic constituents and contamination levels, the dangerous/hazardous
constituents and concentrations, and the physical/chemical waste characteristics that
are acceptable for disposal of wastes at ERDF.
• 59 FR 66414. Radiation Protection Guidance for Exposure to the General Public.
EPA protection guidance recommending (non-medical) radiation doses to the public
from all sources and pathways to not exceed 100 mrem/year above background. It
also recommends that lower dose limits be applied to individual sources and
pathways. One such individual source is residual environmental radiation
contamination after the cleanup of a site. Lower doses limits and individual
pathways are referred to as secondary limits.
• The Future For Hanford: Uses and Cleanup, The Final Report of the Hanford
Future Site Uses Working Group, December 1992.
Cost Effectiveness The selected remedy provides overall effectiveness proportional to its
cost. The cost for the treatment enhancement steps for contaminated soils (radionuclides,
metal and/or organics) appears to be higher than for the other alternatives. However, the
treatment steps will result hi a reduction hi the volume of contaminated soil for disposal, as
well as reducing the costs associated with disposal, backfill and restoration of excavated sites
through recycling of cleaned soils.
In addition, the use of the Observational and Plug-In approaches will ensure that a protective
remedy is implemented, while saving both tune and money required to evaluate and select and
implement remedies on a site by site basis, as well as through combining aspects of
characterization with remediation.
Utilization of Permanent Solutions and Alternative Treatment Technologies to the
Maximum Extent Possible The selected remedy utilizes permanent solutions and alternative
treatment technologies practicable for this site.
Preference for Treatment as a Principal Element The selected remedy utilizes treatment as
appropriate for reduction of the volume of contaminated materials for disposal (e.g. soil
washing, thermal desorption), as well as permanently destroy organic contaminants (thermal
desorption and capture of off-gases).
CERCLA Section 104(d)(4) states where two or more non-contiguous facilities are reasonably
related on the basis of geography, or on the basis of the threat or potential threat to the public
health or welfare or the environment, the President may, at his discretion, treat these facilities
as one for the purposes of this section.
The preamble to the NCP clarifies the stated EPA interpretation that when non-contiguous
facilities are reasonably close to one another and wastes at these sites are compatible for a
42
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selected treatment or disposal approach, CERCLA Section 104(d)(4) allows the lead agency to
treat these related facilities as one site for response purposes and, therefore, allows the lead
agency to manage waste transferred between such non-contiguous facilities without having to
obtain a permit. Therefore, the 100 Area NPL site and the ERDF are considered to be a
single site for response purposes under this ROD. This is consistent with the determination
made in the January 20, 1995 ROD for the ERDF that stated... "Therefore, the ERDF and the
100, 200, and 300 Area NPL sites are considered to be a single site for response purposes
under this ROD."
XH. DOCUMENTATION OF SIGNIFICANT CHANGES
DOE and EPA reviewed all written and verbal comments submitted during the public comment
period. Upon review of these comments, it was determined that no significant changes to the
selected remedy, as originally identified in the Proposed Plan, were necessary.
Xm.TABLES AND FIGURES
Tables and figures for this ROD appear on the following pages.
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Table 1. Reactor Status.
Reactor
B*
C
KE
KW
N
D
DR
H
F
Constructed
1943
1951
1952-1954
1952-1954
1959-1962
1943**
1949**
1948**
1943-1945
Operated
From
1944
1952
1955
1955
1963
1944
1950
1949
1945
To
1968
1969
1971
1970
1987
1967
1964
1965
1965
Status
Retired
Retired
Retired
Retired
Shutdown in
progress
Retired
Retired
Retired
Retired
*B Reactor was held in standby status from 03/1 9/46 to 06/02/48, then restarted.
** Construction dates assumed in correlation with reactor operational dates.
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Table 2. Description of 100-BC-l Operable Unit High-Priority Radioactive Liquid Waste Disposal Sites.
Waste Site
Physical Description
of Waste Site
Former Waste Site Use
'Contaminants of
Potential Concern
116-B-ll Retention
Basin
Reinforced concrete retention basin.
143 m long x 70 m wide x 2 m deep.
Held cooling water effluent from 105-B
Reactor for cooling/decay before release to
the Columbia River. Large leaks of effluent
to soil.
Am-241. Cs-134. Cs-137. Co-60.
Eu-152, Eu-154, Eu-155. Pu-238,
Pu-239, Ra-226. Sr-90. Th-228,
U-238, antimony, chromium, lead,
mercury
116-C-5 Retention
Basin
Two circular steel tanks. 101m diameter x
5 m deep.
Held cooling water effluent from 105-B and
C Reactors for cooling/decay before release
to the Columbia River. Large leaks of
effluent to soil. .
Am-241, Cs-134, Cs-137. Co-60,
Eu-152, Eu-154, Eu-155. Ni-63,
Pu-238, Pu-239, Ra-226, Sr-90,
Th-228, U-238, antimony,
chromium, lead, mercury
116-B-l Process
Effluent Trench
Unlined trench.
108 m long x 9 m wide x 5 m deep.
Received high activity effluent produced by
failed fuel elements, disposed effluent to the
soil.
Cs-137, Co-60, Eu-152, Eu-154,
Pu-239, K-40, Sr-90, U-238,
chromium
116-C-l Process
Effluent Trench
Unlined trench.
175 m long x 38 m wide x 7 m deep.
Received high activity effluent produced by
failed fuel elements, disposed effluent to the
soil.
Am-241, Cs-134, Cs-137, Co-60,
Eu-152, Eu-154, Eu-155, Pu-238,
Pu-239, Ra-226, Sr-90, Th-228.
U-238. antimony, chromium, lead.
mercurv
116-B-l 3 and
116-B-l 4 Sludge
Trenches
116-B-13, unlined trench. 15 m long x
15m wide x 3 m deep.
116-B-14, unlined trench. 37 m long x 3 m
wide x 3 m deep.
Received sludge from retention basins:
sludge disposed to soil then trench
backfilled.
Am-241. Cs-134, Cs-137. Co-60,
Eu-152, Eu-154, Eu-155, Pu-238,
Pu-239, Ra-226. Sr-90, U-238,
antimony, chromium, lead, mercury
116-B-4
French Drain
Gravel filled pipe. 1 m diameter x 6 m
deep.
Received contaminated spent acid from
dummy decontamination facility; disposed
effluent to soil.
Co-60, Cs-137, Eu-152, Eu-154,
Eu-155, Pu-239, K-40. Th-228,
barium.
116-B-12Seal Pit
Crib
Timber reinforced excavation filled with
gravel, soil covered. 3 m long x 3 m wide
x 3 m deep.
Received drainage from confinement seal
system in 117-B building seal pits: disposed
effluent to soil.
None identified
H6-B-5Crib
Concrete covered unlined crib containing
boiler ash and gravel fill. 26 m long x 5 m
wide x 4 m deep.
Received tow-level effluent from
contaminated maintenance shop and
decontamination pad in 108-B building
including tritium waste; disposed effluent to
soil.
Cs-137, Co-60. Eu-152. Eu-154,
H-3. barium, mercury
100-B/C Buried
Process Effluent
Pipelines
Buried process effluent pipelines.
Total length = 6533 m
pipe diameter - varies: leaks have occurred
with known soil contamination.
Transported reactor cooling water from
reactors to retention basins, outfall
structures, and disposal trenches, contains
contaminated sludge and scale.
Cs-134, Cs-137, Co-60, Eu-152,
Eu-154, Eu-155. Ni-63. Pu-238,
Pu-239, Sr-90, U-238
Am-241
Cs-134
Cs-137
Co-60
Eu-152
Eu-154
Eu-155
H-3
^'
amercum
= IJ4cesium
I37cesium
"cobalt
'"europium
'^europium
'"europium
tritium
K-40
Ni-63
Pu-238
Pu-239/240
Ra-226
Sr-90
Th-228
U-238
"'potassium
"nickel
_ 90,
39/MOplutonium
^'radium
'strontium
^thorium
•^uranium
The contaminants of potential concern were identified from the Qualitative Risk Assessment.
Data not available for du's site. Contaminants of potential concern identified based on anologous site 116-D-9 Crib.
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Table 3. Description of 100-DR-l Operable Unit High Priority
Radioactive Liquid Waste Disposal Sites.
Waste Site
116-D-7
Retention Basin
116-DR-9
Retention Basin
116-DR-1.116-
DR-2 Process
Effluent
Trenches
107-D and
107-DR Sludge
Trenches
(includes 5
separate
trenches)
116-D-lAand
II6-D-1B Fuel
Storage Basin
Trenches
•100-Dand
100-DR Buried
Process Effluent
Pipelines
MI6-D-2A
Cribs
H6-D-9Crib
Physical Description of Waste Site
Reinforced rectangular concrete retention
basin; two cells, 142.3 m long x 70.1 m
wide x 7.3 m deep.
Reinforced rectangular concrete retention
basin; two cells, 182.9 m long x 83.2 m
wide x 6. 1 m deep.
Unlined co-located trenches. Length and
width varies, depth 6. 1 m deep.
Unlined trenches.
Trench #1, #2 and #3 are each 32.0 m
long x 9.1 m wide x 3.1 m deep.
Trench #4 - 2S.9 m x 6.1 m x 3.1 m
deep.
Trench 15 - 15.2 m x 6.1 m x 3.1 m
deep.
1 16-D-1A. unlined trench, 39.6 m long x
3.1 m wide x 1.8 m deep.
1 16-D-1B, unlined trench, 30.5 m wide
x 3.1 m wide x 4.6 m deep.
Buried parallel buried process effluent
pipelines. Total length approximately
2.100 m pipe diameter 152 cm buried up
to 6 m below surface.
Unlined earthen structure. 3.1 m x 3.1.m
x 3.1 m deep.
Uniined earthen structure, 3.1 m x 3.1.m
x 3. 1 m deep.
Former Waste Site Use
Held cooling water effluent from 105-D and
105-DR Reactors for cooling/decay before
release to the Columbia River; probably
received ruptured fuel element waste.
Held cooling water effluent from 105-D and
105-DR Reactors for cooling/decay before
release to the Columbia River, probably
received ruptured fuel element waste.
Received effluent overflow from the 116-D-
7 and 116-DR-9 Retention Basins at times
of high activity caused by fuel element
failure.
Received sludge from 116-D-7 and 116-DR-
9 Retention Basins: sludge dredged from
basins, disposed to soil then trench
backfilled.
Received contaminated water from 105-D
Fuel Storage Basin.
Transported reactor cooling water from the
105-D and 105-DR Reactors to the 1 16-D-7
and 1 16-DR-9 Retention Basins, outfall
structures and the 1 16-DR-l and 116-DR-2
Trenches. The buried process effluent
pipelines may contain contaminated sludge
and scale.
Received liquid effluents following fuel
cladding failures from 105-D Reactor.
Received liquid effluent from seal pits in
the 1 17-D exhaust air filter building.
'CoutaiuinaiiLS of Potential
Concern
Cs-134, Cs-137, Co-60, Eu-152,
Eu-154. Eu-155, Pu-238,
Pu-239/240, chromium, Ni-63,
Th-228. U-238
Cs-134, Cs-137, Co-60, Eu-152,
Eu-154, Eu-155. Ni-63, Pu-239,
Sr-90, arsenic, chromium, PCBs,
benzo(a)pyrene. Ra-226, U-238
Cs-134, Cs-137, Co-60, Eu-152,
Eu-154, Eu-155, Pu-239, Na-22,
chromium
Cs-134, Cs-137, Co-60. Eu-152.
Eu-154, Eu-155, Ni-63, Pu-238,
-Pu-239/240, Sr-90. arsenic,
chromium, PCBs, benzo(a)pyrene
Cs-134, Cs-137, Co-60. Eu-152,
Eu-154, Eu-155, Ni-63,
Pu-239/240, Na-22, Ra-226.
Sr-90, Th-228, chromium
Cs-134, Cs-137, Co-60, E4-154,
Er-155, Ni-63, Pu-238, Pu-
239/240. Sr-90, U-238
Cs-137, Co-60. Eu-152, Eu-154,
Ra-226. Sr-90, Th-228
Th-288, arsenic, chromium
Cs-137
Ci>-60
Eu-152
Eu-154
Eu-155
Na-22
Ni-63
Pu-238
Pu-239/240
Ra-226
Sr-90
Th-228
"'cesium
"cobalt
'"europium
'"europium
'"europium
"sodium
°nickel
"'plutonium
°«"'pluionium
°*radium
"strontium
aithorium
The contaminants of potential concern were identified from the Qualitative Risk Assessment
Contaminants are based on analogous site 100-H Buried Process Effluent Pipeline.
Contaminants were identified in soil below 15 feet, and there is little likelihood of exposure to humans and ecological receptors.
-------
Table 4. Description of 100-HR-l Operable Unit High Priority
Radioactive Liquid Waste Disposal Sites.
Waste Site
Physical Waste Site Description
Former Waste Site Use
'Contaminants of Potential
Concern
116-H-7
Retention Basin
Reinforced rectangular concrete retention
basin.
193 m long x 84 m wide x 6 m deep.
Held effluent from 105-H Reactor for
cooling and decay of short-lived
radionuclides before being released to
die Columbia River. Large leaks
occurred .during operation and
underlying soil was contaminated.
Cs-134. Cs-137. Co-tf). Eu-152.
Eu-154. Eu-155. Pu-238.
Pu-239/240, K^O. Ra-226.
Sr-90, Th-228. U-238. arsenic.
chromium, lead, zinc
116-H-l Process
Effluent Trench
Unlined trench.
39 m long x 34 m wide x 5 m deep.
Received reactor cooling water made
radioactive through contact with failed
fuel elements. Received sludge from
116-H-7 Retention Basin when 10S-H
Reactor was deactivated.
Cs-137. Co-60. Eu-152. Eu-154.
Eu-155. Pu-239/240. K-40.
Ra-226. Sr-90, Th-228. arsenic.
chromium
100-H Buried
Process Effluent
Pipelines
Buried parallel process effluent pipelines:
tool length of 1.5 m diameter piping is 902
m: total length of 0 J m piping is 325 m.
Buried up to 6 m below surface; no known
soil contamination.
Transported reactor cooling water from
me 105-H Reactor to the 116-H-7
Retention Basin. 116-H-5 Outfall
Structure, and 116-H-l Process Effluent
Trench. The pipelines may contain
contaminated sludge and scale.
Cs-134. Cs-137. Co-60. Eu-152.
Eu-154. Eu-155. Ni-63. Pu-238.
Pu-239/240. Sr-90. U-238
116-H-4
Pluto Crib
Unlined crib.
3 m long x 3 m wide x 3 m deep; crib was
excavated and removed in 1960 to allow
construction of the 132-H-2 filter building.
Received reactor cooling water
contaminated by failed fuel elements.
Crib was excavated and material buried
in 118-H-5 Burial Ground. A filter
building (132-H-2) was later built on the
116-H-4 Pluto Crib she.
None identified in Qualitative
Risk Assessment
Cs-134
Cs-137
Co-60
Eu-152
Eu-154
Eu-155
K-tO
Ni-63
Pu-238
Pu-239/240
Ra-226
Sr-90
Th-228
U-238
"•Cesium
'"Cesium
"Cobalt
'"Europium
'"Europium
"'Europium
"Potassium
"Nickel
a'Plujonhim
BWMOPlutonium
'"Radium
""Sutmnum
"Thorium
"Uranium
The contaminants of potential concern were identified from me Qualitative Risk Assessment (QRA).
-------
Table 5. 10 Additional High Priority Liquid Radioactive Disposal
Sites from 100-BC-l, 100-DR-l, and 100-HR-l.
ou
100-BC-l
100-DR-l
100-HR-l
Site
Fuel Storage Basin Trench
Pluto Crib
Crib
Crib
French Drain
Dry Well/Quench Tank
Crib
Crib
French Drain
Effluent Disposal Trench
Number
116-B-2
116-B-3
116-B-6A
116-B-6B
116-B-9
116-B-10
116-D-4
116-D-9
116-D-6
116-H-2
Analogous Site
116-D-1A
116-D-2A
116-D-2A
116-D-2A
116-B-4
116-B-4
116-D-2A
116-D-2A
116-B-4
116-B-l
-------
Table 6. 100 Area Analogous Sites.
Waste Site Description
Process Effluent Disposal Trench
Fuel Storage Basin Trench
Dummy Decontamination French
Drain
Process Effluent Retention Basin
Reactor Confinement Seal Pit
Drainage Crib
Process Effluent Outfall Structure
Process Effluent Pipelines
Effluent Pumping Station
Exhaust Air Filter Building
Pluto Crib
Gas Recirculation Building
100-B/C Area
Site
116-B-l
116-B-2
116-B-4
116-B-ll
116-C-5
-
116-B-7
132-B-6
132-C-2
Process Effluent
Pipelines
132-B-4
116-B-3
116-C-2
132-B-5
100-D/DR Area
Site
116-DR-l
116-DR-2
116-D-la
116-D-lb
--
116-D-7
116-DR-9
116-D-9
116-D-5 •
116-DR-5
Process Effluent
Pipelines
132-D-3
117-D
116-D-2a
115-D
100-H Area Site
116-H-l
—
116-H-3
116-H-7
116-H-9
116-H-5
Process Effluent
Pipelines
132-H-3
132-H-2
116-H-4
-------
Table 7. The Hanford Sitewide Background Summary Statistics and Upper
Threshold Limits (UTL) for Inorganic Analytes in Soil.
Analyte
Aluminum
Antimony
Arsenic
Barium
Beryllium
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Potassium
Selenium
Silver
Sodium
Thallium
Titanium
Vanadium
Zinc
Zirconium
95%
Distribution*
(mg/kg)
13,800
MR
739
153
1.62
MR
20,410
23.4
17.9
253
36,000
12.46
7,970
562
0.614
NR
22.4
2,660
NR
1.4
963
NR
3,020
982
733
473
95%
UTLb
(mg/kg)
15,600
15.7°
8.92
171
1.77
0.66C
23,920
27.9
19.6
282
39,160
14.75
8,760
612
1.25
1.4C
253
3,120
5C
2.7
1,290
3.7°
3,570
111
79
573
-------
Analyte
K-40
Co-60
Sr-90
Ku-106
Cs-134
Cs-137
Eu-154
Eu-155
Ra-226
Th-232
U-234
U-235
U-238
Pu-238
Pu-239/240
Am-241
Total Risk
Sample
Average
15
0.067
0.10
8.4e-03
-3e-03
0.55
6e-04
0.05
0.71
0.69
0.67
0.026
0.68
9e-04
0.01
0.14
Maximum
38.2
II
0.432
0.236
0.0848
7.65
0.0978
0.163
1.2
0.893
1 18
0.0552
1.23
0.013
0.04
0.14
95% UCL
(Weibull)
19.7
0.36
1.78
0.98
1.122
1.043
0.035
Concentration to
Reach 10 < Risk
7.71
1.95
3790
128
8.09
2.88
2.65
301
0.707
0.724
326
16.5
68.3
156
139
131
Risk from 75%
Sample
Background
Concentrations
l.95e-04
3.44e-06
3.58e-09
6.55e-09
-3.72e-08
l.9le-05
2.26e-08
l.67e-08
I.OOe-04
'9.52e-05
2.06e-07
l.57e-07
9.93e-07
5.78e-IO
7.l8e-09
l.07e-07
4.l4e-04
Risk from
Maximum
Background
Concentrations
4!97e-04
5.64e-04
l.55e-08
l.84e-07
l.05e-06
2.65e-04
3.69e-06
5.43e-08
I.69e-04
1.23e-04
3.62C-07
3.34e-07
l.80e-06
8.35e-09
2.87e-08
l.07e-07
l.63e-03
Risk from 95%
UCL (Weibull)
Background
Concentrations
2.56e-04
l.29e-08
6.l8e-05
l.38e-04
3.44e-07
l.52e-06
2.5le-08
4.56e-04
-------
Table 9. Endangered and Threatened Species Potentially Found on the 100 Areas.
Species
Notes
Endangered Vascular Plants
Persistentsepal yellowcress
(Rorippa columbiae)
Northern Wormwood
(Artemisia campertris ssp
borealis var workskioldii)
Known to have a scattered distribution because of specialized habitat
requirements or habitat loss; generally occurs in marshy places; known to
inhabit wet shoreline of Hanford Reach in Benton County
Rare, local endemic species near the river; not known from the Hanford Site
but reported just to the north near Beverly, Grant County
Threatened Vascular Plants
Columbia milk-vetch
(Astragalus colvmbianvs)
Hoover's desert parsley
(Lomatium tuberosum)
American white pelican
(Pelecanus erythrorhynchus)
"Peregrine falcon
(Falco peregrinus)
Sandhill crane
(Cms canadensis}
Locally endemic to area near Priest Rapids Dam; could potentially occur in
Northwest portion of the Hanford Site along the Columbia River
Locally endemic to south-central Washington, including Benton County;
known to inhabit rocky hillsides
Endangered Birds
Flocks have recently become common in the Columbia Basin during all seasons
foraging on fish, amphibians, and crustaceans, and roosting on islands
Breeds and winters in eastern Washington, inhabiting open marshes, river
shorelines, wide meadows, and farmlands; nests on undisturbed cliff faces; an
erratic visitor to the Hanford Site
Inhabits open prairies, grainfields, shallow lakes, marshes, and ponds; common
migrant during spring and fall in Washington; some known and suspected
nesting sites in eastern Washington: an occasional visitor at the Hanford Site
Threatened Birds
•Bald eagle
(Haliaeetus leucocephalus)
Ferruginous hawk
(Buteo regaiis)
Pygmy rabbit
(Sylvilagus idahoensis)
Regular winter visitor to the Columbia River, feeding on spawned-out salmon
and waterfowl; they roost in the 100 Areas and nest (unsuccessfully to date)
along the Hanford Reach
Inhabits open prairies and sagebrush plains, usually with rocky outcrops or
scattered trees; known to nest in Benton and Franklin Counties, including the
Hanford Site; rarely winter in Washington, but are known to occasionally
forage on small mammals, birds, and reptiles on sagebrush plains of the
Hanford Site
Threatened Mammals
Inhabits undisturbed areas of sagebrush with soils soft enough to permit
burrows; once known to exist on the Hanford Site west of the 200 Areas
plateau
Source: DOE 1990a-f, DOE 1991a-f
* Indicates both state and federal designation
-------
Table 10. Threatened, Endangered, and Candidate Birds of the Hanford Site
that May Occur in the Vicinity of the 100 Areas.
Common Name
Bald eagle*
Peregrine falconb
American white pelican8
Sandhill crane*
Ferruginous hawk8
Loggerhead shrike*
Sage grouseb
-------
Table 11
ou
IOO-BC-1
100-BC-l
IOO-BC-1
IOO-BC-1
IOO-DC-1
IOO-BC-1
IOO-BC-1
IOO-BC-1
IOO-BC-1
IOO-BC-1
IOO-BC-1
IOO-DR-1
Site
Number
II6-B-I
116-B-2
II6-B-3
1 16-B-4
I16-B-5
II6-B-II
II6-B-I2
II6-B-I3
II6-B-I4
1I6-C-I
1I6-C-5
II6-D-IA
Name
Process Effluent Trench
Fuel Storage Basin
Trench
Pluto Crib
Dummy
Decontamination
French Drain
Crib(IOB-B)
Retention BasinE
Crib(U7-B)
Sludge Trench
Sludge Trench
Process Effluent Trench
Retention Basin
(carbon steel tanks)
Fuel Storage Basin
Trench
IRM
Liquid
Waste
Disposal
X
X
X
X
X
X
X
X
X
X
X
X
Size
M
S
S
S
S
L
S
M
M
L
L
M
Contaminant
Depth A
15-20 FT
7 - 25 FT
4-17 FT
6-20 FTE
6-22.5 FT
20-34 FT
6-26 FT
10 FT
10 FT
36FTF
20 FT
0-56 FT
Est. Depth
to Engr.
Struct.*
15 FT0
15FT
I3FTD
20 FT
M.5FT
20 FT
6 FT
10 FT
IOFT
25 FT
OFT
6FT
Approximate
Overburden
Depth A
0-15 FT
0-1 5 FT
13 FT
20 FT
11.5 FT
4 FT (contam
soil inside
tank)
6FT
4-10 FT
4-10 FT
25 FT
3 FT
8 FT (2 ft
above grade
to 6 ft below
grade)
Principle Contaminants
Rads, Cr, Mn, Zn
Rads, MIBK
Rads, Ag, Cr,
semivolatiles
Rads, nitrate, sodium
oxalate, sodium sulfamate
Rads, Ba, Hg, Zn
Rads, probably Cr, Cu,
Fe, Hg, Mn, Pb, Zn
Rads
Rads, Cr, Cu, Fe, Hg, Mn,
Pb.Zn
Rads, Cr, Cu, Fe, Hg, Mn,
Pb.Zn
Rads, Cr, Mn, Zn
Rads, Cr, Cu, Fe, Hg, Mn,
Pb, Zn, semivolatiles
Rads, Organics, Beta-
BHC, Cd, Cr, Pb, Ni
Approx.
Distance to
Reactor (Ft)
2600
150
60
60
750
2450
.550
2300
2625
2950
1965
130
-------
ou
IOO-DR-1
IOO-DR-1
IOO-DR-1
IOO-DR-1
IOO-DR-1
IOO-DR-1
Site
Number
II6-D-IB
II6DR-2
II6-DR-I
M6-D-7
(107-D)
I6-DR-9
(107-D)
107-D/DR
100-DR-l
IOO-DR-1
IOO-DR-1
1 00-HR- 1
100-HR- 1
1 00-HR- 1
II6-D-2
116-D-9
11 6-1 1-1
II6-H-4
100-H
Name
Fuel Storage Basin
Trench
Liquid Waste Process
Effluent Trench
Liquid Waste Process
Effluent Trench
Process Effluent
Retention Basin
Process Effluent
Retention Basin
Sludge Disposal
Trenches Trench 1
Trench 2
Trench 3
Trench 4
Trench 5
Process Effluent
Pipeline
Pluto Crib
Seal Pit Crib
Process Effluent Disp
Trench
Pluto Crib
Buried Pipelines
IRM
Liquid
Waste
Disposal
X
X
X
X
X
X
X
X
X
X
X
X
Size
M
L
M
L
L
S
S
S
S
S
L
S
S
L
S
L
Contaminant
Depth A
0-20 FT
6-25 FT
6-25 FT
10 to 35 FT
10 to 40 FT
6-19 FT
6- 19 FT
6-19 FT
6-19 FT
6-19 FT
VARIES
IO-I5FT
N/A
0-20 FT
NoCVb
vanes
Est. Depth
to Engr.
Struct.*
I5FT
20 FT
20 FT
24 FT
20 FT
10 FT
10 FT
10 FT
10 FT
10 FT
VARIES
10 FT
10 FT
15FT
10 FT
varies
Approximate
Overburden
Depth A
17 FT (2 ft
above grade
to 15 ft below
grade)
20 FT
20 FT
14 FT
10 FT
16 FT
16 FT
16 FT
16 FT
16 FT
VARIES
N/A
15 FT
IOFT
vanes
Principle Contaminants
Rads, Organ ics, Cr, Pb,
Zn
Rads, Organ ics, Ag, Cd
Rads, Organ ics, Ag, Cr,
Zn
Rads, Di-n-butly
phthalate, phenol, Cr
Rads, Organics, As, Cd,
Cr.Ni
Unknown
Unknown
Unknown
Unknown
Unknown
Rads, Acetone, Methylene
Chloride, Toluene
Rads, Organics
Rads, Acetone
Rads , As, Cr, Pb, PNA
semivolatiles
unknown
Rads, Trit, U
Appro*.
Distance to
Reactor (Ft)
130
2500
2500
2150
1750
2250
2250
1750
2100
2300
625
900
250
900
-------
Table 11
ou
100-HR- 1
1 00-HR- 1
Site
Number
II6-H-7
II6-H-2
Name
Retention Basin
Effluent Disposal
Trench
IRM
Liquid
Waste
Disposal
X
X
Size
L
M
Contaminant
Depth A
16-26 FT
N/A
Est. Depth
to Engr.
Struct/
20 FT
10 FT
Approximate
Overburden
Depth A
4 FT
10 FT
Principle Contaminants
Rads with less than
0.5pCi/g
Rads, Tritium
Approx.
Distance to
Reactor (Ft)
1100
250
NOTES: A. Estimated depths are measured from current grade around the site and are based on limited or incomplete information.
Actual depths may vary considerably from estimates.
B. No contaminated volume - contaminants removed.
C. II6-B-I: Constructed with gravel Till 15-21 FT; overburden = 1-15 FT, 15-21 FT engineered design fill.
D. Depth includes 3 FT of mounding above local grade. Without mounding depth = 10 FT.
E. Contaminant depths assumed.
F. Minimum thickness (depth) borehole ended in contaminated material; top of saturated zone is approximately 49 feet below
ground surface.
* Data based on reported values in the Rev. 0 LFI and draft FFS.
N/A = Not applicable
S = Small
M = Medium
L = Large
-------
Waste
Site/Group
(Retention
Basin)
II6BII
Extent of Contamination
Volume
(IHJ)
118835.0
Length
(i»)
210.3
Width
(in)
III. 3
Area
(m1)
23406.0
Depth
(in)
6.1
Media/
Material
Soil
Concrete
Contaminant
Radionuclides
"C
"Co
'"Cs
"'P.u
"•Eu
"Ni
"'Pu
imwpt,
"Sr
»"U
Inorganics
Arsenic
Cadmium
Chromium VI
Lead
Maximum
Concentration
Detected
(a)
pCi/g
2.59(10')
4.39(10*)
S.SOdO2)
2.83(10')
8.24(10')
5.10U04)
7.66
3.40(10')
2.\0(\tf)
9.00
me/kg
(e)
i_i
to
n
h-I
I
I
ff
n
-------
Waste
Site/Group
(Retention
Basin)
II6-C-5
100 B/C Buried
Pipelines
100 B/C Pipeline
Soil (Leak al
function Box)
Extent of Contamination
Volume
(nij)
145210.0
302973.0
1 325.0
Length
(in)
(c)
6533.0
76.2,
Width
(iu)
(c)
varies
5.8
Area
(nr)
23805.0
varies
441.0
Depth
(HI)
6.r
varies
3.0
Media/
Material
Soil
Concrete
Soil
Sleel
Concrete
Sludge
Soil
Concrete
Contaminant
Radionuclides
"'Am
"C
"Co
"'Cs
'"Eli
'"Eli
Ml
2MPu
""«Pu •
"Sr
H*rti
Inorganics
liarium
Cadmium
Chromium VI
Lead
Mercury
Radionuclides
"Co
"'Cs
"3Ru
i«Eu
'"F-u
"Ni
"MM
»OT40pu
"Sr
Radionuclides
"Co
«OT«PU
"Sr
Maximum
Concentration
Detected
(a)
pCi/e
3.40(ltf)
2.59(10')
1. 95(10")
2.\S(\Ci/^
2.8KI01)
l.lUltf)
i.esdo1)
3.4KI01)
9.42(10')
6.l8(l(r)
l.4l(ltf)
2.80(10")
2.04(1 01)
nCi/e
4.64(10')
1.00(10)
1.36(10)
er
55"
!
o
St
B"
-------
Waste Silc/Gruiip
116 ni (Process RlTluciil
Disposal Trench)
II6-C-I (Process Effluent
Dis|H)sal Trench)
II6-B- 13 (Sludge Trench)
Kxlctil itf Cnulaiiiiualion
Vuhiuie
(UIJ)
3001.0
314410
924.0
l.tiiglh
(ill)
112.2
1698
15.2
Width
(in)
13.1
32.6
15.2
Area
(in1)
1470.0
5535.0
228
Depth
(in)
4.6
5.8
4.0
Media/
Material
Soil
Soil
Concrete
Sludge
Cuuiaiuinaut
Inorganics
Chromium VI
Manganese
Kadionuclides
'"Cs
i»Ru
""""IM
Inorganics
Chromium VI ,
Radiiinuclides
"'Am
"C
'"Cs
'"liu
"Ni
"Sr
Ml
my
Inorganics
Arsenic
Uarium
Cadmium
Chromium VI
Mercury
Lead
Maximum
Concentration
Detected
(a)
mg/kg
3.30(10')
8.39(10")
nCi/g
1.18(10')
6.63
5.30
me/kg
(e)
(b)
(h)
5?
cr
n"
9
!
s?
-------
Waste Site/Group
1 16 B 14 (Sludge Trench)
1 16 B-4 (French Drain)
1 16 B 12 (Seal Pit Crib)
1 16 B 5 Crib
Exleul uf Ciiulauiuiatiiiu
Vuliuue
(ui1)
439.0
3.2
0.0
1022.0
Length
(m)
36.6
12(0
0.0
29.0
Width
(in)
3.0
12(1)
0.0
8.2
Area
(m1)
1100
II
0.0
232.0
Ocpth
(m)
•40
2.7
0.0
43
Mwlia/
Material
Sludge
Soil
Steel
NA
Soil
Concrete
Cnulauiiuant
Radionuclides
"'Am
"C
'"Ct
"Co
'"liu
"•liu
"Ni
"•hi
"Sr
"111
Tritium
"Ml
Inoreanics
Arsenic
llariuin
Cadmium
Chromium VI
Mercury
Uad
Radionuclides
"Co
"'Cs
'"Cu
'"liu
•«"«PU
None
Radionuclides
'"l!u
'II
Inorganics
Barium
Mercury
Maximum
Concentration Detected
(a)
b
b
nCi/e
2.68(10')
2.08(10')
4.20(10')
4.54(10')
8.60
e
pCi/g
1.15(10')
2.96(10*)
me/te
4.84(10')
2.90
a Where concentration exceeds preliminary remediation goals.
b Based on retention basin group data.
c Contamination is defined by an additional 12.2 in (40 D) radius beyond the retention basin walls
d Data is from pipeline sludge. Although the in situ PKG are exceeded, impact to groundwaler is expected to be negligible due
to containment of the material by the pipe.
c Based on Process Document group data.
f 1.2 m (4 fl) is the diameter of the trench drain
g .Assumed to meet in situ PRO.
h No quantitative data is available. Constituents are assumed from Miller and Wahlen 1987.
COPC « contaminants of potential concern
NA - not applicable
Dimensions - Contaminated volume dimensions from the PI:S.
r.»r> - ,(».... ! !~n ,n.l .lrr..n,mi..i,,,iinn
er
JT
I
9
I
Z
sr
-------
Waste Site
(group)
I16-D-7
(retention basins)
107 D/DR #1
(sludge trench)
Kxtent of Contamination
Volume
(m1)
125760.0
2316.0
•
Length
(m)
148.4
38.1
Width
(m)
79.2
15.2
Area
(m1)
1 1753.0
652.0
Depth
(m)
10.7
4.0
Media/
Material
Soil
Concrete
Sludge
Sludge
Kenned
COPC
Radionuclides
"C
""Co
'"Cs
"2Eu
'*Eu
'H
"wwpu
"Sr
Inorganics
Chromium VI
Radionuclides
"C
IJ7Cs
"Co
IJJEu
'"Eu
'H
"Sr
»6Ra
Inorganics
Arsenic
Cadmium
Chromium VI
Maximum
Concentration
Detected
(a)
pCi/g
4.3xl02
3.05x10'
1.32x10'
2.96x10*
9.94x10'
1.98xI04
2.90x1 0J
3.73x10*
mg/kg
5.16x10"
assumed from
116-DR-9and
116-D-7data
tf
cr
-------
Waste Site
(group)
107 D/DR n
(sludge
trench)
Extent of Contamination
Volume
(in1)
2316.0
Length
(in)
38.1
Width
(m)
15.2
Area
(m2)
572.0
Depth
(m)
4.0
Media/
Material
Sludge
Refined
COPC
Radionuclides
I4Q
IJ7Cs
"Co
IMEu
IJ4Eu
JH
K8Tli
Inorganics
Arsenic
Cadmium
Chromium VI
Maximum
Concentration
Detected
(a)
assumed from
l!6-DR-9and
1 16-D-7 data
t
(0
I
-------
Waste Site
(group)
107 D/DR #3
(sludge trench)
Extent of Contamination
Volume
(m>)
2316.0
Length
(HI)
38.1
Width
(in)
15.2
Area
(m1)
579.0
Depth
(m)
4.0
Media/
Material
Sludge
Refined
COPC
Radionuclides
i4C
"7Cs
"Co
132Eu
IMEu
JH
239/240 pu
MSr
Inorganics
Arsenic
Cadmium
Chromium VI
Maximum
Concentration
Detected
(a)
assumed from
M6-DR-9and
H6-D-7data
2
£
n
I
I
sr
-------
Waste Site
(group)
107 D/DR #4
(sludge
trench)
Extent of Contamination
Volume
(i»J)
1561.0
Length
(m)
32.0
Width
("0
12.2
Area
(m2)
390.0
Depth
(m)
4.0
-
Media/
Material
Sludge
Refined
COPC
Radionuclides
MC
"7Cs
"Co
IJ2Eu
IMBu
3H
"Sr
Inorcanics
Arsenic
Cadmium
Chromium VI
Maximum
Concentration
Detected
(a)
assumed from
M6-DR-9and
lI6-D-7data
e
o
m
I
-------
Waste Site
(group)
107 D/DR #5
(sludge treiu.il)
•
Extent of Contamination
Volume (in1)
2005.0
Length
(m)
27.4 .
Width
(in)
18.3
Area
(m2)
501.0
Depth
(m)
4.0
Media/
Material
Sludge
Refined
COPC
Radionuclides
"C
IJ7Cs
wCo
IJ4Eu
JH
339/140 pu
wSr
Inorganics
Arsenic
Cadmium
Chromium VI
Maximum
Concentration
Detected
(a)
assumed from
H6-DR-9and
1 16-D-7 data
cr
n"
n
I
-------
Waste Site
(group)
II6-DR-9
(retention
basin)
'
I16D-IA
(fuel storage
basin trench)
Extent of Contamination
Volume
(i»J)
260414.0
4409.0
Length
(in)
210.3
43.3
Width
(in)
101.5
6.7
Area
d»2)
21345.0
290.0
Depth
(m)
12.2
15.2
Media/
Material
Soil
Concrete
Sludge
Soil
Refined
COPC
Radionuclides
"C
"Co
"7Cs
IHEu
'"Eu
239/740 py
H«Ra
"•Sr
I28Th
Inorganics
Arsenic
Cadmium
Chromium VI
Radionuclides
l37Cs
l32Eu
239/240 pu
n«Ra
Inorganics
Cadmium
Chromium VI
Lead
Maximum
Concentration
Detected
(a)
nCi/g
1.8x10*
2.07x10'
3.25xlOJ
l.llxlO4
3.98xlOJ
6.50x10'
1.25
1.70x10'
1.02
nig/kg
1.24x10'
1.20
7.34x10'
nCi/g
2.57x10'
9.17
8.30
4.28x10'
mg/kg
1.00
l.OSxlO2
5.l9xl02
n
i-»
U)
o
I
-------
Waste Site
(group)
116-D-IB
(fiiel storage
basin trench)
116DR-I/2
(process
effluent
trench)
II 6-0-2 A
(plulo crib)
1I6-D-9
(seal pit crib)
Extent of Contamination
Volume
(m1)
2947.0
24.447.0
14.4
0.0
•
Length
(in)
39.6
varies
3.1
0.0
Width
(m)
12.2
varies
3.1
0.0
Area
(in*)
483.0
4,215
9.6
0.0
Depth
(m)
6.1
5.8
1.5
0.0
Media/
Material
Soil
Soil
Soil
Timbers
NA
Refined
COPC
Radionuclides
'"Cs
'"Eu
239/240 pu
Inorganics
Chromium VI
Lead
Radionuclides
"7Cs
'«Eu
239/740 pu
Inorcanics
Cadmium
Chromium VI
Radionuclides
M6Ra
None
Maximum
Concentration
Detected
(a)
pCi/c
2.49x10'
9.72
5.30
3.04x10'
2.20x10'
pCi/p
8.30x10*
4.42x10'
1.40x10'
mp/kj!
1.10
1.86x10*
pCi/p
1.3x10'
NA
s
£
m
i
n
3f
r
-------
Waste Site
(group)
100 D/DR
(pipelines)
Extent of Contamination
Volume
(in1)
(b)
,
Length
("0
(b)
Width
(in)
(b)
Area
(m1)
(b)
Deptli
(m)
(b)
Media/
Material
Steel
Concrete
Refined
COPC
Radionuclides
'"Cs
IMEu
IMEu
IJ5Eu
<3Ni
Maximum
Concentration
Detected
(a)
pCi/K
assumed from
pipeline group
data
(a) Where concentration exceeds preliminary remediation goals from the FFS.
(b) Based on retention basin group profile
(c) Based on group profile
(d) No quantitative data is available. Constituents are assumed from Miller and Walilen 1987.
(e) It is assumed that burial grounds contain immobile forms of waste; thus, no contaminants are assumed to exceed the reduced infiltration
concentrations.
(0 no soil contamination has been identified associated with die pipelines, therefore no volume calculation is made; extent of contamination is
limited to the pipeline itself.
COPC contaminants of potential concern
D&D* decontamination and deconunissioning
NA not applicable
I
CO
I
i—»
f
I
-------
Waste Site (group)
1 16- II -7 (retention
basin)
II6H-I (process
ellluem trench)
•i
116 H-4 (plulo crib)
Kxtcnl of Conlaminution
Volume
(m1)
S6483.0
12.015.0
0.0
Length
(ni)
201.8
S8.8
0.0
\Viillh
(m)
93.3
33.5
00
Area
(in1)
18828.0
1970.0
0.0
Depth
(m)
3.0
6.1
0.0
Media/
Material
Soil
Concrete
Soil
NA
Kenned
core
Radionuclides
"Co
'"Cs
"2Eu
1MEu
»«Pu
M»/2«Opu
*Sr
Inorcanics
Arsenic
Lead
Radionuclides
"Co
'"Cs
IJJEu
IS4Eu
mnwpy
Inorganics
Arsenic
Chromium
VI
Lead
Oreanics
Chrysene
None
Maximum
Concentration
Detected
(a)
pCi/g
2.20 x 10'
2.01 x 10'
1.72x 104
5.68 x 10'
6.78
2.00 x 107
2.38 x 107
me/kg
4.7 x 10'
5.40 x 107
pCi/g
3.42 x 10'
4.01 x 107
5.30 x 107
8.8 x 10'
1.1 x 10'
me/kg
3.79 x 10'
2.96 x 10'
l.87x 107
pph
9.20 x 107
NA
I
n
?
-------
Waste Site
(group)
100 II pipeline
(Pipeline)
132 II 1
Reactor
Exhaust Slack
(D&D facility)
132-11-2
Filler Building
(D&D facility)
132 II 3
Effluent
Pumping
Station (D&D
facility)
Kxteiil of ('ontaniinalion
Volume
(m1)
)
0.0
0.0
0.0
Length
(in)
0>)
0.0
0.0
00
Width
(m)
(b)
0.0
0.0
0.0
Area
(m1)
0«)
0.0
0.0
0.0
Depth
(m)
0»
0.0
0.0
0.0
Media/
Material
Slcel
Concrete
NA
NA
NA
•
Refined
COI'C
Radionuclides
«°Co
IJ7Cs
"2Eu
'"Eu
6JNi
»'Pu
"Sr
None
None
None
Maximum
Concentration
Detected
(a)
assume data from
pipeline group
NA
NA
NA
I
I
n
9
(a) Where concentration exceeds preliminary remediation goals from the PPS.
(b) No comaminaied soil is associated with (he site; therefore, no volume of contamination is calculated; extent of contamination is limited to the pipeline
itself.
(c) Based on group data.
COPC = contaminants of potential concern
NA = not applicable
D&D = decontamination and deconunissioning
-------
Table 15. 'Qualitative Risk Assessment Summary for 100-BC-l Interim Remedial Measure Sites.
Waste Site
116-B-ll Retention
Basin
116-C-5 Retention Basin
Pipeline sludges
Pipeline soils
116-B-l Process Effluent
Trench
116-C-l Process
Effluent Trench
116-B-13and 116-B-14
Sludge Trenches
16-B-4 French Drain
116-B-12Crib
116-B-5Crib
'Human Health Risk Estimates
'Residential Land Use
Incremental
Cancer Risks
>lx 10*
> 1 x lO'2
> 1 x 1C'2
3 x 10-3
> 1 x 10-2
> 1 x lO'2
> 1 x 10-2
> 1 x 10-2
5x 10-
2 x 10-3
Noncancer
Hazard Index
2.5
2.5
NA'
<1
<1
2.5
2.5
<1
2.5
<1
*Recreational Land Use
Incremental
Cancer Risks
> 1 x 10"2
> 1 x 10-2
> 1 x lO"2
2x 10°
1x10"
2x ia3
> 1 x 10'2
3x 10-
3x 10*
1 x 10-3
Noncancer
Hazard Index
<1
<1
NA5
<1
<1
<1
<1
<1
<1
<1
Ecological Risk
Estimates
(Environmental
Hazard
Quotient)
>1
>1
>1
<1
<1
>1
>1
>1
<1
<1
3.
4.
5.
The Qualitative Risk Assessment provides an evaluation of the need for interim remedial measures at 100-BC-l sites.
Human health and ecological risks estimated in die QRA are based on conservative assumptions that may overstate die
level of potential risks. Actual risks associated with the 100-BC-l sites are likely to be lower than those presented
here.
Corresponds to a frequent-use scenario in the FFS.
Corresponds to an occasional-use scenario in the FFS.
NA = Not applicable. Noncarcenogenic contaminants not detected at this site. No hazard index was calculated for
this site.
-------
Table 16. Qualitative Risk Assessment1 Summaryfor 100-DR-l Interim Remedial Measure Sites.
Waste Site
1 16-D-7 Retention Basin and
107-D Sludge Disposal
Trenches
116-DR-9 Retention Basin and
107-DR Sludge Disposal
Trenches
116-DR-l and 116-DR-2
Process Effluent Trenches
116-D-lAand 116-D-1B Fuel
Storage Basin Trenches
100-D and 100-DR Buried
Process Effluent Pipelines5
116-D-2ACrib
6ll6-D-9Crib
^uman Health Risk Estimates
'Residential Land Use
Incremental
Cancer
Risks
4x 1C"'
> 1 x 10"2
> i x ia2
> i x ia2
> 1 x ID"2
8x 10-3
5x itr
Noncancer
Hazard
Index
<1
<1
<1
<1
N/A
N/A
>1
Recreational Land Use
Incremental
Cancer
Risks
3x 10-*
> 1 x ID"2
2X1CT1
2x 1(T .
> 1 x 10;2
5x 10-'
3 x 1O*
Noncancer
Hazard
Index
<1
<1
<1
<1
N/A
N/A
<1
Ecological Risk
Estimates
(Environmental
Hazard Quotient)
<1
>1
>1
<1
>1
<1
<1
1. A qualitative risk assessment provides an evaluation of the need .for interim remedial measures at 100-DR-l
sites.
2. Human health and ecological risks estimated in the qualitative risk assessment are based on conservative
assumptions that may overstate the level of potential risks. Actual risks associated with the 100-DR-l sites
are likely to be lower than presented here.
3. This corresponds to a frequent-use scenario in the FFS.
4. This corresponds to an occasional-use scenario in the FFS.
5. Data are not available for risk calculations. Risks estimates were based on analogous site 100-H buried
process effluent pipeline.
6. Risk estimates were based on analogous site 116-H-9 Crib.
N/A - Not Applicable. Noncarcinogenic contaminants not detected at this site. No hazard index was
calculated for this site.
-------
Table 17. Qualitative Risk Assessment1 Summary for 100-HR-l Interim Remedial Measure Sites.
Waste Site
116-H-7
Retention Basin
116-H-l Process
Effluent Trench
100-H Buried
Process Effluent
Pipeline Sludge
116-H-4 Pluto
Crib
'Human Health Risk Estimates
'Residential Land Use
Incremental
Cancer
Risks
> 1 x 10'2
> 1 x lO*2
> 1 x 10'2
Noncancer
Hazard
Index
2
2
NA
'Recreational Land Use
Incremental
Cancer
Risks
> 1 x 10-2
Sxltf4
> 1 x Iff2
Noncancer
Hazard
Index
0.04
0.03
NA
'Ecological Risk
Estimates
(Environmental
Hazard Quotient)
> 1.0
> 1.0
> 1.0
Site has been previously addressed.
*A qualitative risk assessment provides an evaluation of the need for interim remedial measures at 100-HR-l sites.
'Human health and ecological risks estimated in the qualitative risk assessment are based on conservative
assumption that may overstate the level of potential risks. Actual risks associated with the 100-HR-l sites are
likely to be lower than presented here.
'Corresponds to a frequent-use scenario in the FFS.
'Corresponds to an occasional-use scenario in the FFS.
NA - Not Applicable.
-------
1
Site
Containment
Duration
(yr)
Removal/Disposal
Duration
(yr)
In Situ Treatment
Duration
(yr)
Removal/Treatment/Disposal
Duration
(yr)
100 BC-I OPERABLE UNIT
1 16-0-1 1 Retention Basin
1 16-C-S Retention Basin
1 16 B 13 Sludge Trench
116 B 14 Sludge Trench
116 Bl Process Effluent Trench
1 16 Cl Process Effluent 1 reach
1 16 B 5 Crib
II6-B-4 French Drain
100 B/C PIPELINES
1 18 B 5 Burial Ground
118 B 7 Burial Ground
118 BIO Burial Ground
01
O.I
2.4
O.I
O.I
O.I
0.7
0.7
O.I
O.I
O.I
0.5
O.I
O.I
2.4
O.I
0.1
O.I
0.2
0.2
0.7
3.8
0.3
O.I
0.2
O.I
O.I
0.2
1.5
1.7
O.I
O.I
0.2
0.6
O.I
O.I
2.5
0.1
O.I
0.1
I
n"
oo
W
2
I
I
Si
o
n
f
§.
o
-------
Sile
Ciiiilaiiiinenl
Duration
(yrs)
Renuwal/Disposal
Duration
(yrs)
In Situ Treatment
Duration
(yrs)
Removal/Treatment/Disposal
Duration
(y«)
100 DRI OPEKAIiLK UNIT
1161)7
107 D/DR SLUDGI! 'IVRNCIII-S
#1
n
#3
#4
#5
116DR9
116-0 1 A
1161) IB
II6DR 1/2
II6D2A
100 D/DR FIFIil INK
I18-D-4A
M8-D-4D
118-D-I8
1.6
O.I
0.1
O.I
1.2
O.I
O.I
O.I
O.I
O.I
1.4
0.2
O.I
0.4
O.j
1.0
O.I
O.I
O.I
0.4
0.4
0.4
0.3
0.3
3.1
O.I
0.1
O.I
O.t
O.I
2.1
0.1
O.I
O.I
0.1
O.I
3.2
0.3
0.1
0.5
0.1
0.1
O.I
O.I
I
n
i—»
VS
s
(—I
V)
ff
k
•a
I
-------
i
fir
srre
•I
Cuiiiaiiunenl
Ouraliiin
(yrs)
Removal/Disposal
Duration
(yrs)
In Situ Trealmenl
Duration
(yrs)
Removal/Treatment/Disposal
Duration
(yn)
IOO-IIR-1 OPURABLK UNIT
II6-II-7 Retention Basin
116 II 1 Process limuenl Trench
116 II 4 Pluto Crib
100 II PIPELINBS
0.5
0.2
8.1
1.0
0.2
Nit interim action proposed al site
O.S
0.3
O.I
o
o
w
s.
f?
s
a
I
-------
Sile
Containment
Capital
O&M
Present
Worth
Removal/Disposal
Capital
O&M
Present
Worth
In Situ Treatment
Capital
O&M
Present
Worth
Removal/Trealment/Disposal
Capital
O&M
Present
Worth
100 UC-I OPERABLE UNIT
II6D II
lelenlion Basin
II6C-5
NOTES:
• Costs are in millions of dollars
• O&M - Operation and Maintenance
• NA - Not Applicable to the Waste Sile (see FFS Report)
• Costs presented are based on a diHcren! exposure scenario than the selected scenario, but the relative differences between alternatives is similar (see FFS Report Tor detailed cost
analysis).
• Costs presented are preliminary, and are presented Tor comparison purposes only. It is expected thai actual costs will be significantly lower.
•4
n
-------
Site
II6-D-7
Containment
Capital
($ uiilliuu)
N/A
O&M
N/A
Present
Wurth
(( uiilUuu)
N/A
Remove/Dispose
Capital
($ milliou)
81.5
O&M*
-
Present
Worth
($ million)
76.8
lu Situ Treatment
Capital
($ million)
N/A
O&M
($ million)
N/A
Present
Worth
($ milliou)
N/A
Reujovc/Trcat/Dispose
Capital
($ milliou)
82.30
O&M
($ million)
12.60
Present
Worth
($ million)
87.70
107 D/DR Sludge Trenches
11
12 "
#3
*4
#5
1I6-DR9
II6D-IA
116!) IU
1 16 DR 1/2
II6D2A
100 D/DR
ripeliiie
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
32.3
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
14.8
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
38.1
1.69
1.75
1.72
1.27
1.31
102
4.69
1.95
13.90
0.28
9.03
-
-
-
-
-
-
-
-
-
-
-
1.61
1.67
1.64
1.22
1.25
96
4.47
1.86
13.3
0.27
8.61
3.53
3.61
3.58
2.63
.2.85
N/A
N/A
N/A
31
0.60
3.68
2.24
2.29
2.27
1.56
1.78
N/A
N/A
N/A
23
0.09
0.00
5.49
5.63
5.57
4.00
4.42
N/A
N/A
N/A
48.80
0.66
3.51
2.08
2.13
2.11
1.68
1.72
100.20
4.88
2.29
13.70
0.71
N/A
0.27
0.28
0.27
0.19
0.21
24.50
0.95
0.41
3.48
0.01
N/A
2.24
2.30
2.28
1.79
1.84
114.00
5.57
2.58
16.30
0.70
N/A
NOTES:
• Costs are in millions of dollars
• CAP - Capital
• O&M - Operation and Maintenance
• PW - Present Worth
• NA - Not Applicable to the Waste Site (see PI;S Report)
• Costs presented are based on a different exposure scenario than the selected scenario, but the relative differences between alternatives is similar (see FPS Report for detailed cost
analysis).
• Costs presented are preliminary, and are presented for comparison purposes only. It is expected that actual costs will be significantly lower.
-------
Table 23. Summary of Estimated Costs for 100-HR-l Operable Unit Remedial Alternatives.
SITE
116-H-7
116-H-l
Pipelines
Containment
CAP
NA
NA
$9.76
O&M
NA
NA
$0.2
PW
NA
NA
$11.9
Remove/Dispose
CAP
$29.4
$6.08
$2.27
O&M
$0
$0
$0
PW
$28.0
$5.79
$2.16
In-Situ Treatment
CAP
$66.9
NA
$0.94
O&M
$6.77
NA
$0
PW
$98.0
NA
$0.90
Remove/Treat/Dispose
CAP
$31.9
$6.53
NA
O&M
$4.1
$0.83
NA
PW
$34.2
$7.02
NA
NOTES:
• Costs ate in millions of dollars
• CAP - Capital
• O&M - Operation and Maintenance
• PW - Present Worth
• NA - Not Applicable to the Waste Site (see FFS Report)
• Costs presented are based on a different exposure scenario than the selected scenario, but the relative differences between alternatives is
similar (see FFS Report for detailed cost analysis).
• Costs presented are preliminary, and are presented for comparison purposes only. It is expected that actual costs will be significantly lower.
-------
Table 24. Half-Life.
Isotope
Potassium-40
Cobalt-60
Strontium-90
Technetium-99
Ruthenium- 106
Antimony- 125
Iodine-129
Cesium- 134
Cesium- 137
Europium- 152
Europium- 154
Europium- 155
Radium-226
Thorium-232
Uranium-233
Uranium-234
Uranium-235
Uranium-238
Neptunium-237
Plutonium-238
Plutonium-239
Plutonium-240
Plutonium-241
Americium-241
Curium-244
Symbol
«K.
"Co
»°Sr
"Tc
106Ru
125Sb
I29J
134Cs
137Cs
IJ2Eu
154Eu
IS5Eu
226Ra
U2Th
a3U
^U
asu
a«u
B7Np
:38pu
239pu
240pu
24,pu
241 Am
244Cu
Half-Life
1.28xlO'yr
5.3 yr
29.1 yr
2.12 x 10s yr
367 days
2.7 yr
1.57xl07yr
2.06 yr
30.2 yr
13.5 yr
8.6 yr
4.75 yr
1600 yr
1.4xlOI0yr
1.6xl05yr
2.4 x 10s yr
7 x 108 yr
4.5 x 10' yr
2.14 xlO6
87.7 yr
2.4xl04yr
6537 yr
14.4 yr
433 yr
18.11
Isotopes in bold are naturally-occurring.
-------
Table 25. MTCA Soil Levels for Metals and Organics.
METALS METHOD A
Aluminum
Arsenic 20.0
Barium
Berylium
Boron
Cadmium 2.0
Chromium (III) 100.0
Chromium (VI)
Copper
Iron
Lead 250.0
Manganese
Mercury 1.0
Nickel
Sodium
Vanadium
Zinc
OTHER INORGANICS
Ammonium/Ammonia
Chloride
Cyanide
Fluoride (Fluorine)
Nitrate
Nitrite
Sultate
VOCs
Acetone
Chloroform
Methylene Chloride 0.5
Perchloroethylene
1,1,1 -Trichlorethane 20.0
Trichloroethene
OTHER ORGANICS
Acetic Acid
Ethylenediamine
Ethylenediamine tetraacetic
acid (EDTA)
Formic Acid
Hydrazine
PCBs 1.0
Petroleum Products/Deisel oil 200.0
Thiourea (Ethylene thiuorea)
•all concentrations are mg/kg
n/a = no level has been established
METHOD B
n/a
6.00e+001
5.60e+003
4:00e + 002
7.20e+003
4.00e+001
8.00e+004
4.00e+002
2.96e+003
n/a
n/a
4.00e-(-002
2.40e-(-001
1.60e-i-003
n/a
5.60e+002
2.40e + 004
2.72e+006
n/a
1.60e+003
4.80e+003
1.28e+005
8.00e + 003
n/a
8.00e+003
8.00e-l-002
1.33e+002
1.96e-(-001
7.20e-i-003
9.096+001
n/a
1.60e+003
n/a
1.60e-i-005
3.33e-001
1.30e-001
2.006+002
6.40e-HOOO
-------
Table 26. Groundwater Protection Standards.
Constituent
Am-241
C-14
Co-60
Cs-134
Cs-137
Eu-152
Eu-154
Eu-155
K-40
Na-22
Ni-63
Pu-239/240
Pu-238
Ra-226
Sr-90
Tc-99
Th-228
Th-232
Tritium
U-234
U-235
U-238
Antimonv
Arsenic
Barium
Cadmium
Chromium
Lead
Mansanese
Mercurv
Zinc
Units
pCi/L •
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
DCi/L
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
ue/L
ue/L
ue/L
ue/L
ue/L
ue/L
ue/L
ue/L
ue/L
Groundwater Protection
Standard
Value
1.2
1.467.0
147.0
13.0
29.0
800.0
800.0
4.000.0
280.0
59.0
44.0
1.2
1.6
5.0
8.0
4.000.0
10.0
2.0
20.000.0
20.0
24.0
24.0
6.0
50.0
2.000.0
5.0
100.0
15.0
50.0
2.0
5.000.0
Source
0.04»DCG
MCL
MCL
MCL
MCL
0.04»DCG
0.04*DCG
0.04*DCG
0.04*DCG
MCL
MCL
0.04*DCG
0.04»DCG
MCL
MCL
0.04«DCG
MCL
0.04*DCG
MCL
0.04»DCG
0.04»DCG
0.04*DCG
MCL
MCL
MCL
MCL
MCL
MCL
MCL
MCL
MCL
DCG =1Derived Concentration Guide, DOE Order 5400.5
MCL = Maximum Concentration Level (40 CFR 141.16)
-------
Table 27. Columbia River - Ambient Water Quality Criteria
Protective of Aquatic Organisms.
COPC
Antimony
Arsenic (III)
Barium
Cadmium
Chromium (VI)
Lead
Manganese
Mercury (II)
Zinc (EPA 1987)
Aroclor 1260
Benzo(a)pyrene
Chrysene
Pentachlorphenol
Freshwater Aquatic Life
1600/xg/l
190 ng/l
N/A
1.1 /zg/1 *(salmon)
lUg/1
. 3.2Mg/l*
N/A
0.012^8/1
HOMg/1*
N/A
N/A
N/A
3.2 Mg/1 (pH = 6.5)
* Assumes a hardness of 100 ppm as CaCO3.
-------
Figure 1. Hanford Site.
Sea
Spokane
ROJ6C7 SITE
Vanco
_^-v
Portland
Old Hanford
Townsite
Yakima
Barricade
200 West
Area
Washington Public
Power Supply
System
Rattlesnake Springs • . •
WNP-2 .WNP-4
* «WNP-1
Wye Barricade
400 Area Fast •
Flux Test Facility
•-T. . . Battelle
'T_. Observatory
Advanced
Nuclear
Fuels
Richland
WestRichland
8 KILOMETERS
!
5 MILES
LEGEND
[•XI Arid Lands Ecology Reserve
£3$ City of Richland
U..:-:••;I Saddle Mountain National Wildlife Refuge
PT/i Washington State Department of Game Reserve
Source: OOE-RL 1982.
903-1272^6168^-3-92
-------
Figure 2. Map of the IOO-B/C Area Showing tl
Source and Groundwater Operable Units.
i
UECENO:
e Monitoring Well
+ Septic Tank
116 Liquid Waste Unite
118 Solid Wast* Units
1607 Septic Tanks
132 Decommissioned Radioactlvely
Contaminated Facility
—— Source Operable Unit Boundary
• -• » Groundwater Operable Unit Boundary
NOTE:
The heavy dashed line indicates the
preliminary limits of the 100-9C-5 operable
unit
I-ie-tl M11UOVMSU
-------
Figure 3. 100-DR-l Operable Unit.
SEE
SHEET 2
FOR
DETAILS
j
MITOtS
UOOCl
UMk* Jfemaratin*
UiiOTMra* r«*lr
rmr »
hTSK. ,
Wgtw f«y in4
> Wtur mm IM-O/KI-0
9
Mo* iul> rrMtodM >ltnln« il |l»ihm.
WftfM* MM C.U>
-------
and Origtaa! Facilities.
Lift Station
and Effluent
Monitoring
' Station
1716 Shops
and Gas
Pump
11S;H.2
1607-H10
116-H-9
N761-Hjt16-H-1
his-H-a" '
116-H-2 \ House
132-H-2
116 Liquid Waste Units
N9300Q H8 Solid Waste Units
132 Decommissioned
Radioactive!/ Contaminated
Facilities
1607 Septic Tanks
2S3 Demolished or Backfilled Facilities
— Operable Unit Boundary
Note: Facility location
3000 METERS
10000 FEET
903 1272/28246/8-3-92
-------
Figure 5. Flooded Area for the Probable Maximum Flood.
GRANT CO. I
uS-D/OB-vea /frfc-
Old Han
ot. 11A Townsite
Yakima
Barricade
200 West'
Area
2iUU.S.
State of Ecology
Washington
(leased)
Washington Public
Power Supply
Rattlesnake Springs
Wye Barricade I WNP-2 .WNP-4
400 Area Past m
Flux Test Facility
300 Area PNL&
Westmghouse
Hanford
Advanced
Nuclear
Fuels
•~l Baneile
'-i_ Observatory
LEGEND
Areas Flooded
8 KILOMETERS
5 MILES
Source: DOE 1982.
903-1279/26298/4-27-92
-------
100 Area Waste Sites
Soil Sites
Solid Waste Sites
Uqu.dT»,»..,
Retention Basins
(116)
Liquid Dl.po..l
Burial Grounds
(118)
Trenches
(116)
Process Elllu.nl
IS
Cribs/I
Septic Systems
(1607)
(116)
Fuel Storage Basin
Discharge
Sludge
Pipelines
Pluto Crib
Outfall Structures
(116)
Special
Burial Grounds
Notes;
( ) Number In parenthesis Is the waste
site prolix.
— Represents potential future site group.
o\
t
g.
1
3
5
v*
S-'
Seal Pit Crib
Dummy Decon Crib/
French Drain
ITH:JJA:P114A-Mc2
-------
Expedited Response
Action (ERA) Path
Draft 100 Area
Work Plans
Interim Remedial
Measure (IRM)
Path
Limited Field
Investigation
Path to Achieve
Interim Remedial
Measure (LFI IRM)
Data
Evaluation
A
Are
Data
Sufficient
to Formulate
Conceptual Model and
Qualtadv* Rlik
Assessment
7
C
Determine Minimum
Data Requirements
lor IRM Path
Can
Additional
Required Data be
Obtalnad by Untiled
Raid Investigation
1
0
onse \
teded 7 V— +•
me /
Trl Party
Agreement
Memorandum
EE/CS (CERCLA)
Permit Modification
(RCRA)
Inflate ERA
-»•
Public
Comment
Public
Comment
-»
Trl-Party Agreement
Action Memorandum
*•
Perform and
Complete ERA;
Integrate Schedule
Define Threshold
Contamination Levels;
Formulate Conceptual
Model and Qualitative
Risk Assessment;
Perform FS Screening
Defer Further
Investigations to
Cumulative Risk
Evaluation Phase
Negotiate Scope of
Work. Relative Priority.
and Incorporate kilo
Integrated Schedule;
Perform LFI
1
IRM Proposed
Plan Integrated
Schedule
Public
Comment
Issue IRM
Rtcord o( Decision
(IRM ROD)
Perform IRM;
Concurrent
Characterization
Final Remedy
Selection lor
Operable Unit
Asiest Accumulation ot Data
lromAAMS.ERA.IRM.LFI
Path* and Feasibility Studies tor
Operable Unit and Aggregate
Area RUk Astettment Needs
and Final Remedy Selection
Determine
Minimum Data
Needs. Relative
Priority ot Work;
Incorporate Into
Integrated
Schedule
Perform and Complete
Field Investigations;
Document Through Work
Plan Addendum*.
Meeting Mnulee. and
Scope ol Work
Statements
Proposed Plan/
Public Comment
Can
Operable
Unit/Aggregate
Area ROD be
Issued
Perform Focused
Feasibility Study
(studies)
Goto
A or Eat
Appropriate
JJA:HPPS-BC
-------
Figure 8. Northeast to Southwest Geological Cross Section of the Suprabasalt Sediments
Across the Western Wahluke Syncline in the Vicinity of the 100-B/C, 100-K, 100-N,
100-D/DR, and 100-H Areas of the Hanford Site.
100 B/C
L100N
1.100 Hj
Gable
Mountain
Anticline
FSA
Wahluke
Syndine
Approximate Location
of Cross Section
n
03
HG
HSZ
UR
FSE, FSC,
FSB & FSA
LM
OB
Horizontal
Scale
Vertical F^ 1 Wlometsr
' 50 Meters
Vertical
Exaggeration
18x
LEGEND
Location of Borehole used
in Cross Section
Gravelly Deposits,
Hanford Formation
Sandy to Silty deposits,
Hanford Formation
Upper Unit, Ringold Formation
Fluvial Gravel-Dominated
Intervals. Ringold Formation
Lower Mud. Ringpid Formation
Overbank Deposits,
Ringold Formation
Basalt
Formation Contact
Fades Association or
Unit Contact
Contact Inferred or Uncertain
Source: Undsey 1991.
903-1272/26315/8-4-92
-------
A
SOUTH
p
ui
ui
UJ
ui
600
500
400
300
200
100
0
100
200
300
400
500
in
ID
I
HANFORO PLANT COORDINATES (FEET)
to
I
10
I
A'
NORTH
- Saddle Mountain Basalt Outcropping _
Water Table
Elevation -400
Fit* Sand and Giavel
1 Giava) and
SitiySand
• • Sandy Gravel
Sand and Qav«l Oaval/Sand '
wlhS« • Sand.SMwiirr ' .
" —— »- t_Qiay»l. Clay and Cafcfte
:_=—ii_--_- .-_Si«.Sand;Clar«rth:—_
— „ . .Giavel and Catch*
Lower Ringold Fm
:— — Cta». Sand. Ash '—1-'
-Hanlord Fm ''
,—- -400
Middle Ringotd Fm •
Saddle Mountains Basalt
Ellensburg Fm
LEGEND
»
"^" '— Estimated Geologic Contact
I Perforated Interval
NOTE: See Figure 2-16 lor Location ol Cross Section
Note: tm equals 3.28 ft.
Vertical Exaggeration = 10X
0 300 METERS
1000 FEET
O
§
9
O,
O
O
i
§
w
n
903-1280/26431/2-27-92
-------
Figure 10. Generalized Stratigraphk Column for the 100-H
Areas, Assumed to be Similar in the 100-D/DR Area.
1
CO
0>
£
.2
re
_«
UJ
450 r
400
350
300
250
200
150-
100-
50-
"2.2
£13
re§
o
cE
if o
•o
V
i
o
in
0>
I
o
v>
o
O o>
_ «"
LEGEND
(53 Clay
^•irVJ Sand
IS Gravel
3 Caliche
Ash
Basalt
Water Table
&
0)
o Sediment Classification
,HR-1
Vf/47§7~ "
J7
6/87
DR-1
Source: LJiKalaetaL 1988.
Ellensburg Formation
Elephant Mountain Member
Silty Sandy Gravel
Gravelly Silty Sand
Silty Sand
Silty Clayey Sand
te Sandy Silty Ciay
Basalt
Ash. Gravel. Sand. Silt. Clay
Basalt
903 1273/26313/7-27-92
-------
Primary Primary Secondary Secondary Transport Primary
Sources Release Sources Release Media Exposure
Mechanisms Mechanisms Routes
Receptors
Secondary
Exposure
Routes
Reactor &
Ancillary
Facilities
(I) Includes all facilities that received process effluents.
including pipelines, basins, cribs, trenches, trench drains,
and outfall structures.
(2) Includes other sources within limited existing information.
(3) Includes exposure to radiation.
LEGEND:
» Potential Exposure Pathway
» Potential Primary Exposure Pathway
f"> Primary contaminant sources and known contaminated media
n
i
a
*•
a
I
i1
n
I
I
if
9
O
1
o;
n
I
903 1272/26410/8-4-92
-------
APPENDIX A
SUMMERS MODEL APPROACH FOR THE PROTECTION OF GROUND WATER
AND THE COLUMBIA RIVER
The Summers model has been evaluated to estimate residual contaminant concentrations in the
soil that will be protective of groundwater and of the Columbia River. This appendix presents an
overview of the methodology for those two efforts, and the general input parameters for the
model. Additional detail and the conditions for application at specific waste sites will be
finalized and approved by EPA and Ecology during remedial design activities based on
information provided by DOE. Information that is being developed under the 100-BC-l
expedited response action is expected to provide significant information regarding validation of
the model code, assumptions, and sensitivity of input parameters to observed field conditions.
Groundwater Methodology. Constituent concentrations can be calculated using the Summers
Model, which was rearranged to solve for concentration in groundwater. The rearranged model
is presented below:
C (Q * Q ) - Q C.
9* P gv _ 9* J-
Q
P
The terms of the equation are defined as:
C^ = Concentration hi groundwater (pCi/L or Ug/L)
Qp = Volumetric flow rate to groundwater (fWday);
calculated as Ap x q
Ap = Horizontal area of contamination (ft2)
q = Recharge rate (ft/day)
Q^ = Groundwater flow rate (ftVday);
calculated as V x h x w
V = Darcy velocity in groundwater (ft/day)
h = Thickness of the zone of mixing hi aquifer (ft)
w = Width of mixing zone in aquifer (site width) (ft)
Q = Initial concentration hi groundwater (pCi/L or ug/L)
Concentration in soil is calculated from Cp (leachate concentration) as follows:
A-l
-------
The terms of the equation are defined as:
C, = Concentration in soil (pCi/g or ug/g)
Cp = Concentration in leachate (pCi/g or ug/g)
Kj = Distribution coefficient (mL/g)
For contaminants where the Kj value is zero, the concentrations in soil are calculated as follows:
The terms of the equation are defined as:
m = volumetric moisture content (unitless)
d = dry soil density (g/ml)
Distribution coefficients for radionuclides and inorganics are estimated from literature reviews.
Distribution coefficients for organics will be estimated as follows:
The terms of the equation are defined as:
KOJ = Soil organic carbon constant (mL/g)
foe = Fraction of organic carbon in soil
Assumptions^The major assumptions in the modeling effort include:
o The vadose zone between the waste site and the groundwater is uniformly contaminated.
o Recharge from rainfall is constant
o Flow in the aquifer is constant
o The lithology of the vadose zone is constant
o Infiltration will equilibrate with existing contamination and mix completely with the
upper 15 feet of the aquifer.
A-2
-------
Input Parameters
Parameter
Concentration in Groundwater
Volumetric Flow to
Groundwater
Horizontal Areas of
Contamination
Recharge Rate
Groundwater Flow Rate
Darcy Velocity in Groundwater
Porosity
Thickness of Mixing Zone in
Aquifer
Width of Mixing Zone
Volumetric Moisture Content
Dry Soil Density
. Symbol
c..
QP
AP
q
Q~
V
n
h
w
m
d
Value
Contaminant Specific
Site Specific
Site Specific
Variable
Variable
Variable
Variable
15 Feet
Site Specific
0.09
1.7g/ml
Comment
Maximum Contaminant Levels
(MCL's)
Area of Waste Site x Average
Annual Recharge Rate
Estimated Surface Area of Site
Varies for Site to Site
V x h x w
Pore velocity/porosity
Porosity of Geologic
Formation
Average Depth of RCRA
Equivalent Well Screen
Width of waste Site
Perpendicular to Groundwater
Flow
Soil Moisture Average 5
Percent (w/w) or 9 Percent by
Volume
Based on approx value of 1 10
Ibs/fV
Columbia River Protection Methodology. The selected alternative requires that source areas
do not affect groundwater such that discharges to the Columbia River could adversely affect
aquatic species. The methodology below presents a simplified approach to estimate attenuation
factors that-represent the effect of radiological decay as a radionuclide moves from a waste site to
the river, and mixing within the groundwater that results from river water flowing into the
ground and mixing (diluting) groundwater prior to discharge to the river environment.
Attenuation factors can be multiplied by the desired water quality goal and used as input to the
Summers model as approved by EPA and Ecology. The "multiplied water quality goals" can
then replace the term C^ as described in the previous section of this Appendix. The model can
then be used to estimate residual soil contaminant levels that would be expected to be protective
of aquatic life in the Columbia River. .
A-3
-------
Methodology. A three step process is presented to estimate residual contaminant levels that
would be protective of the Columbia River. The first step (applicable to radionuclides) estimates
the effect of radioisotope decay while the contaminant moves from the waste site to the river.
The second step accounts for mixing within the groundwater that results from river water flowing
into the ground and mixing (diluting) groundwater prior to discharge to the river environment.
The third step combines radioactive decay and mixing, then computes a concentration value for
residual contamination.
Step 1.
The contaminant travel time to the river is determined as follows:
T.D/V .R
T = Time for contaminant to reach river (plug flow)
D = Distance between the river and the individual waste site
Vw = Average pore velocity of the water
Soil retardation factor
During the period T, the radioactive contaminants will decay by an amount given by the equation
below:
C^ = (0.5)*(T/HL)
Where:
HL = Half life of the radionuclide
CR = level or radioactivity of an isotope when it reaches the river
C«, = Level of radioactivity of an isotope assumed leaving the waste site
The measure of the ability of the groundwater system to provide time for each radionuclide to
decay before reaching the river is the inverse of the above equation and is referred to as the decay
attenuation factor. Radionuclides with limited decay, or mobile contaminants with no decay, are
assumed to reach the groundwater/river interface at the same level as at the waste site (i.e. a
decay factor of 1 .0).
Step 2
Surface water protection criteria areapplied at the point of exposure to the organism (e.g. 18
inches.into the river substrate for protection of the early life stages of salmon). The decay
A-4
-------
attenuation factors may be multiplicative. Total attenuation factor = (decay attenuation factor) x
(mixing attenuation factor)
Step 3
The ambient water quality criteria are then multiplied by the appropriate total attenuation factors,
and applied in the Summers model for the term C^.
Assumptions
o Inflow of river water and mixing with groundwater occurs due to two processes. First,
during periods of high river level relative to the nearby groundwater, river water flows
into the river bank, and mixes with groundwater. When discharge to the river resumes,
groundwater contaminants have been attenuated. Second, turbulent mixing within the
river bottom can occur to a depth in the substrate that is deeper than that utilized by many
aquatic organisms. For both these conditions, at the point of exposure the organism may
be exposed to groundwater contaminants that have been attenuated by mixing with river
water. Calculating the amount of mixing is a hydrodynamically difficult problem. Based
on limited seep data, and well data, it is believed to vary between a factor of 2 to 5.
A-5
-------
APPENDIX B
USDOE HANFORD 100-BC-l, 100-DR-l AND 100-HR-l
RESPONSIVENESS SUMMARY
The U.S. Department of Energy (DOE), the U.S. Environmental Protection Agency (EPA), and
the State of Washington, Department of Ecology (Ecology) held a public comment period from
June 26, 1995 through August 9,1995 for interested parties to comment on the Proposed Plans
for 100-BC-l, 100-DR-l and 100-HR-l operable units (OU's). The Proposed Plans presented the
preferred alternative for high priority liquid radioactive effluent waste sites in those OU's. A
public meeting was held on July 25,1995 at the Richland Public Library, 955 Northgate Drive in
Richland, Washington to describe the remedial technologies that were evaluated and to present
the preferred alternative. Numerous discussions were held with the Hanford Advisory Board
(HAB), including presentations to the HAB at the May 1995 and August 1995 meetings.
A responsiveness summary is required by the Comprehensive Environmental Restoration
Compensation and Liability Act for the purpose of providing the agencies and the public with a
summary of citizens comments and concerns about the site, as raised during the public comment
period, and the agencies responses to those comments.
I. RESPONSIVENESS SUMMARY OVERVIEW. This section briefly describes the
background of the Hanford Site 100 Area and outlines the preferred alternatives for the 100 Area
Operable Units.
II. BACKGROUND ON COMMUNITY INVOLVEMENT AND CONCERNS. This
section provides a brief history of community interest and concerns regarding the 100 Area
Operable Units.
HI. SUMMARY OF MAJOR QUESTIONS AND COMMENTS RECEIVED DURING
THE PUBLIC COMMENT PERIOD AND THE AGENCIES' RESPONSES TO THOSE
COMMENTS. This section summarizes both oral and written comments submitted to the
agencies at the public meeting and the public comment period, and provides the agencies'
responses to those comments.
IV. REMAINING CONCERNS. This section discusses community concerns that the agencies
should be aware of as they prepare to undertake remedial designs and remedial actions at the 100
Area Operable Units.
B-l
-------
I. RESPONSIVENESS SUMMARY OVERVIEW
SITE BACKGROUND The Hanford Site was established during World War II as part of the
"Manhattan Project" to produce plutonium for nuclear weapons. Hanford Site operations began
in 1943, and DOE facilities are located throughout the Hanford Site and the City of Richland.
Certain portions of the Hanford Site are known to have cultural and historical significance and
may be eligible for listing in the National Register of Historical Places.
In 1988, the Hanford Site was scored using EPA's Hazard Ranking System. As a result of the
scoring, the Hanford Site was added to the NPL in July 1989 as four sites (the 100 Area, the 200
Area, the 300 Area, and the 1100 Area). Each of these areas was further divided into operable
units (a grouping of individual waste units based primarily on geographic area and common .
waste sources). The 100 Area NPL site consists of the following operable units for contaminated
sources such as soils, structures, debris, and burial grounds; 100-BC-l, 100-BC-2,
100-KR-l, 100-KR-2,100-NR-l, 100-DR-l, 100-DR-2, 100-HR-1,
100-HR-2,100-FR-l, 100-FR-2,100-IU-l, 2,3, and 4; for contaminated groundwater; 100-BC-
5, 100-KR-4,100-NR-2,100-HR-3, and 100-FR-3. The actions in this ROD addresses all of the
known high priority liquid effluent disposal sites in the 100-BC-l, 100-DR-l and 100-HR-1
OU's. This ROD will require actions at 37 of the 128 waste sites known to include engineered
structures (out approximately 300 total known releases) in the 100 Area.
In anticipation of the NPL listing, DOE, EPA, and Ecology entered into a Federal Facility
Agreement and Consent Order in May 1989 known as the TriParty Agreement. This agreement
established a procedural framework and schedule for developing, implementing, and monitoring
remedial response actions at Hanford. The agreement also addresses Resource Conservation and
Recovery Act (RCRA) compliance and permitting.
OPERABLE UNIT BACKGROUND
100-BC-l The 100-BC-l Operable Unit is one of three operable units associated with the 100
B/C Area at the Hanford Site. The 100-BC-l and 100-BC-2 operable units address contaminant
sources while the 100-BC-5 Operable Unit addresses contamination present in the underlying
groundwater. The 100-BC-l Operable Unit encompasses approximately 1.8 km2 (0.7 mi2) and is
located immediately adjacent to the Columbia River shoreline. In general, it contains waste units
associated with the original plant facilities constructed to support B Reactor operation, as well as
the cooling water retention basin systems for both B and C Reactors. The B Reactor, constructed
in 1943, operated from 1944 through 1968, when it was retired from service. The C Reactor,
constructed in 1951, operated from 1952 until 1969, when it also was retired from service.
Currently, the only active facilities in the 100-BC-l Operable Unit are those that extract and treat
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water from the Columbia River and transport that water to other 100 Area and 200 Area facilities.
JOO-DR-1 The 100-DR-l Operable Unit is one of three OU's associated with the 100 D/DR
Area at the Hanford Site. The-100-DR-l and 100-DR-2 are source OU's. The third OU, 100-
HR-3 is the groundwater OU for D/DR and H Areas. The 100 D/DR Area contains two reactors;
the D reactor associated with the 100-DR-l OU, and the DR Reactor associated with the 100-
DR-2 OU. The D Reactor operated from 1944 to 1967 when it was retired. The DR reactor
operated from 1950 to 1964 when it was retired. The 100-DR-l OU encompasses approximately
1.5 km2 (0.59 mi2) and is immediately adjacent to the Columbia River. Currently, sanitary and
fire-water protection is provided to the 100 H and 100 F Areas from the 100 D Area.
100-HR-l The 100-HR-1 Source Operable Unit is one of two source operable units associated
with the 100 H Area at the Hanford Site. The 100-HR-l and 100-HR-2 Source Operable Units
address contaminant sources while the 100-HR-3 Groundwater Operable Unit addresses
contamination present in the underlying groundwater. The 100-HR-l Source Operable Unit
encompasses approximately 0.41 km2 (0.16 mi2) and is located immediately adjacent to the
Columbia River shoreline. The operable unit contains waste units associated with the original
plant facilities constructed to support the H Reactor. The area also contains evaporation basins
which received liquid process wastes and non-routine deposits of chemical wastes from the
300 Area, where fUel elements for the N Reactor were produced. These solar evaporation basins
received wastes from 1973 through 1985 and are regulated under RCRA as treatment, storage,
and disposal facilities. The H Reactor complex was constructed after World War II to produce
plutonium for use in military weapons. The H Reactor operated from 1949 to 1965, when it was
retired. Currently there are no active facilities, operations, or liquid discharges within the
100-HR-l Source Operable Unit.
SUMMARY OF THE PREFERRED ALTERNATIVE
Remove/Treat/Dispose - This alternative applies to sites with contaminated soil and structures,
and includes the following elements:
• remove contaminated soils, structures, and debris
• thermal desorption, if required, for soil
» soil washing, as appropriate
• disposal of contaminated materials at an approved facility
backfill of excavated areas and revegetation.
Under this alternative, the contaminated materials would be excavated as described under the
remove/dispose alternative. Materials contaminated with organic chemicals at levels exceeding
waste disposal acceptance criteria would be treated (e.g. by thermal desorption) as necessary to
met waste acceptance criteria. It may then be recombined with the remaining contaminated soils
prior to soil washing.
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Following removal and treatment, contaminated soil and/or contaminated products resulting from
treatment technologies would be disposed of onsite at the ERDF. The excavation would be
backfilled with washed soils and other soils as needed and revcgetated.
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II. BACKGROUND ON COMMUNITY INVOLVEMENT AND CONCERNS.
The sites addressed in this ROD are high priority waste sites that received radioactive liquid
discharges during the operational period of the reactors in the 100-BC-l, 100-DR-l and 100-HR-
1 Operable Units. These sites were identified as high priority for interim actions due to having
the highest likelihood for adverse impacts to human health and the environment, and particularly
as potential sources for release of contaminants to the Columbia River. Protection of the
Columbia River has been identified by stakeholders as being a high priority value. This value
has been articulated at numerous public forums, and through letters written to the TriParty
organizations.
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III. SUMMARY OF MAJOR QUESTIONS AND COMMENTS RECEIVED DURING
THE PUBLIC COMMENT PERIOD AND THE AGENCIES' RESPONSES TO THOSE
COMMENTS.
Significant comments received during the public comment are presented in this section.
Responses to the comments follow each comment. Some of the comments are representative of
numerous comments on the same topic, while others are presented verbatim. Some comments
were received that were not related to the 100 Area Operable Units. Copies of all comment
letters that were received are attached to this responsiveness summary. A transcript of the public
meeting was made and is available for review at the Information Repositories.
COMMENT 1. Numerous commentors expressed support for the preferred alternative of remove,
treat (as appropriate or required) and dispose. Furthermore, the actions associated with the
preferred alternative would support major stakeholder values of protection of the Columbia
River, striving to meet the goal of unrestricted use for the 100 Area by meeting residential
cleanup standards, and getting on with cleanup.
RESPONSE. Comments accepted.
COMMENT 2. Numerous commentors expressed a concern that public involvement needs to
continue as the TriParty organizations finalize site specific source cleanup standards for
protection of groundwater for those sites where either there is no soil exposure route
(remediation is for protection of groundwater) and/or the site is under consideration for leaving
contamination in place that would not allow for unrestricted use.
RESPONSE. Additional public comment will be requested prior to any decision to leave
contamination in place under such circumstances.
COMMENT 3. Several commentors supported the regulatory agencies suggestion to
redesignated RCRA Past Practice (RPP) sites under this ROD as CERCLA Past Practice (CPP)
sites.
RESPONSE. A TriParty change package has been approved that redesignated the 100-DR-l and
100-HR-1 operable units as CPP units. Ecology maintains lead regulatory authority at these
sites.
COMMENT 4. Planning and implementation of the preferred alternative should be done in such
a manner that balances cleanup with protection of the health and safety of workers and the
public, protection of natural resources, and minimizes the area and volume of disturbed soil.
RESPONSE. Remedial design planning will address concerns about worker health and safety,
protection of the public, and protection of cultural and natural resources during implementation
of remedial actions. The design of remedial actions will include safety analyses, and worker
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health and safety plans to assure protection of workers and the public during remedial action.
Remedial design also will include surveys of sites for cultural and natural resources to assure that
disturbances of identified resource areas are minimized to the extent possible.
COMMENT 5. Exposure pathways other than ingestion of food may present significant
exposure for the great basin pocket mouse.
RESPONSE. Other pathways of exposure from soil to the pocket mouse are likely to be present.
These include external exposure to radiation, inhalation of contaminated dust, and contaminated
soil ingestion from grooming. However, the Qualitative Risk Assessments (QRA's) used to
evaluate site risks were not intended to be full baseline risk assessments. The QRA's provided a
relative comparison of site risks for use in selecting sites for interim remedial action. Ecological
risks generally were not drivers in identifying sites for interim remedial action. A more complete
evaluation of exposure pathways will be undertaken prior to selection of any final actions.
COMMENT 6. The Hanford Future Site Uses Working Group recommended unrestricted land
use for the 100 Areas. That recommendation should be the basis for land use considerations for
the 100 Area cleanup actions.
RESPONSE. One of the goals as stated in the ROD is to meet this recommendation.
COMMENT 7. The costs associated with Natural Resource injuries at ERDF and in the 100 Area
associated with the preferred alternative are not presented in the Proposed Plans.
RESPONSE. Evaluation of potential natural resource injuries at ERDF is a component of the
ERDF mitigation action plan implementation. Specific mitigation plans for the 100 Area
remedial actions will be developed during the remedial design. The intent of these mitigation
plans will be restoration of the sites and to avoid or minimize impacts to natural resources
during cleanup activities to the extent practicable. Because the waste sites to be remediated in
the 100 Area occur within areas previously disturbed by reactor operations and agricultural
activities, remediation and revegetation actions will likely result in improving rather than
degrading ecological conditions in the area.
COMMENT 8. Revegetation of remediated waste sites should be done only with native plants
and should to the greatest extent possible attempt to restore the natural diversity.
RESPONSE. A revegetation pilot project is currently in the planning stages. The purpose of
this project is to test techniques for revegetation with native plants. This project's successes and
failures will be used as guidance to plan revegetation on a wider (landscape) scale during
remedial design.
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COMMENT 9. In the event that in the future irrigation occurs in the 100 Area, residual
chromium in soils may move into groundwater, reach the Columbia river and have an adverse
effect on salmon.
RESPONSE. The cleanup goals developed for the proposed remedial actions do not currently
take irrigation into consideration. In the event irrigation occurs in the future that could cause
additional releases of chromium, the effectiveness and degree of protection provided by the
remedy would need to be re-evaluated.
COMMENT 10. The cumulative impacts of leaving waste in place at multiple sites needs to be
addressed, particularly in the context of establishing allowable limits of residual contamination.
RESPONSE. Cumulative impacts from multiple sites were not evaluated in the context of the
QRA's, since the objective of the QRA's was no provide a "yes/no" answer for the
implementation of an interim action at a waste site. It is expected that cleanup goals for
protection of human health and the environment would reduce risks such that potential contact
with soils at multiple sites would not result in cumulative risks that exceed allowable levels.
COMMENT 11. The impacts of multiple contaminants at each site also should be evaluated in
the context of allowable limits for wastes left in place.
RESPONSE. Cumulative impacts at individual waste sites from multiple contaminants were
evaluated in the QRA's. Additional evaluation of multiple radionuclide concentrations to meet
the 15 mrerri/year dose level will be undertaken as part of the remedial design activities.
COMMENT 12. An irrigation scenario should be assumed for the purposes of evaluating
candidate sites for leaving waste in place.
RESPONSE. The cleanup goals developed for the proposed remedial actions do not currently
take irrigation into consideration. In the event irrigation occurs in the future that could cause
additional releases of chromium, the effectiveness and degree of protection provided by the
remedy would need to be re-evaluated.
COMMENT 13. Disposal of wastes from the 100 Area actions at the ERDF or W^025 do not
meet the disposal criteria expected for commercial nuclear waste disposal facilities - that waste
disposal areas support general unrestricted use 100 years after closure.
RESPONSE. Disposal of 100 Area wastes in either the WO-25 facility or the ERDF will be
equivalent to performance requirements for commercial nuclear facilities. This conclusion is
based on the results of performance assessment (PA) analyses completed for each of the
facilities.
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The NRC defines a waste classification system which designates waste as Class A, B, and C to
protect the inadvertent intruder. Both WO-25 and the ERDF have been designed to be essentially
equivalent to Class C which is the most protective of the Classes. The NRC also requires that an
all pathways dose of 25 mrem/yr from use of contaminated groundwater should not be exceeded
as a result the disposal of commercial waste. For ERDF, waste acceptance criteria have been
developed using a more stringent level of 4 mrem/yr as the basis.
COMMENT 14. The proposed plans are very general in nature and should provide more specific
information on the alternatives.
RESPONSE. The Proposed Plans are intended to summarize the information that is contained
in other documents. The Focused Feasibility Studies provides the details concerning the remedial
alternatives and the evaluation of these alternatives. A list of the pertinent documents used to
develop the Proposed Plans are referenced in the back of the Proposed Plans and are available for
review at the Administrative Record locations (also identified in the back of the Proposed Plans.
COMMENT 15. The proposed plans do not present specific cleanup standards.
RESPONSE. The proposed plans cited the governing environmental statutes and proposed rules
that contain the numerical standards for the specific contaminants. The specific values are
presented in Tables 25,26, and 27 of the ROD.
COMMENT 16. Will the cleanup goals and action levels protect future native uses of the sites
near the river, including eventual intrusion into the sites.
RESPONSE. Although a final land use determination has not been made for the 100 Area, the
present cleanup goals are intended to not preclude future uses of the sites. Cleanup goals for
nonradioactive contaminants are based on State of Washington Model Toxics Control Act
(MTCA) cleanup levels for unrestricted residential use of sites. Similarly, cleanup goals for
radionuclides are based on achieving a dose limit of 15 mrem/year above background based on a
residential use scenario. There is additional discussion on the topic of eventual intrusion and
timeframes under the response to Comment 21.
COMMENT 17, Several sites were proposed as "no action" sites. The no action sites should be
characterized by DOE to assure that contamination levels are at or below the appropriate cleanup
standards before proceeding with no action or institutional controls.
RESPONSE. Sites that were identified as "No Action" at this time are only considered as not a
candidate for an interim action. No final decision has been made regarding those sites.
COMMENT 18. EPA should revise the CRP to allow the Yakama Indian Nations (YIN) to
review additional information prior to the completion of RD and the start of RA.
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RESPONSE. Under DOE's and EPA's government to government relationship, documents are
provided to the YIN at the same time EPA and Ecology receive them. Therefore, the CRP does
not require revisions for the YIN to review additional information prior to the completion of the
remedial design. The information referred to by the YIN is contained in the 100 Area
documents, most notably in the FFS reports. Additional information that the YIN has requested
input towards is related to site specific restoration plans. It is the intent of the TriParties to have
full participation by the YIN, and other affected stakeholders, during the development and
implementation of the site revegetation plans.
COMMENT 19. When is work expected to begin for the 100 Area cleanups ?
RESPONSE. CERCLA section 120 (e)(2) requires \hal..."Substantial and continuous physical
onsite remedial action shall be commenced at each facility no later than 15 months after the
completion of the investigation and the study." Therefore, such actions must commence no later
than 15 months after the signature of this ROD. Current planning assumptions for RD/RA
activities, and the availability of the ERDF for acceptance of wastes, are projecting initiation of
full scale remediation in the mid to late summer 1996 timeframe.
COMMENT 20. Has a temporary disposal facility been designed for storage of wastes that will
be RCRA compliant and be able to withstand weather effects and inadvertent intrusion for an
indefinite timeframe ?
RESPONSE. Compliance with substantive requirements of RCRA will be addressed for the
design of any temporary waste storage units during remedial design activities that will follow
this ROD. Adverse weather effects will also be evaluated at that time. It is not necessary to
evaluate inadvertent intrusions for an indefinite timeframe since by definition a temporary
storage unit would be utilized for a finite period of time.
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COMMENT 21. At what point in time is general intrusion assumed to occur ? [NOTE. The
author of this comment suggested that 500 years past closure is a reasonable timeframe to
assume general intrusion.]
RESPONSE. For the majority of sites, the expectation is that intrusion could safely occur at any
time post-remediation. This expectation is based on the assumption that the majority of sites
would be remediated to levels that would allow for unrestricted use. For sites that may be
considered to be candidates to leave some level of wastes in place, the primary contaminants of
concern are expected to be radionuclides. The specific radionuclides and the associated half lives
are; Cesium-137 (30.2 years), Europium-154 (7.8 years), Europium-155 (5 years) and Strontium-
90 (28.9 years). Radioactive decay for these contaminants would eventually allow for
unrestricted intrusion. The table below presents relevant radioactive decay timeframes and
associated reduction of activity for these contaminants.
Half
Life
1
2
3
4
5
6
7
8
9
10
Percent
Reduction
50%
75%
87.5%
93.75%
96.9%
98.4%
99.2%
99.6%
99.8%
99.9%
Cs-137
Years
30.2
60.4
90.6
120.8
151
181.2
211.4
241.6
271.8
302
Co-60
Years
5.3
10.6
15.9
21.2
26.5
31.8
37.1
. 42.4
47.7
53
Eu-152
Years
13.5
27
40.5
54
67.5
81
94.5
108
121.5
135
Eu-154
Years
7.8
15.6
23.4
31.2
39
46.8
54.6
62.4
70.2
78
Sr-90
Years
28.9
57.8
86.7
115.6
144.5
173.4
202.3
231.2
260.1
289
For most of the high priority liquid effluent disposal sites addressed by this ROD, discharges
ceased nearly 30 years ago. Therefore, all of the above listed radionuclides have experienced at
least one half life. Five half life cycles results in a 96.9 percent reduction in radioactivity and
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therefore a reduced level of potential risk. In 120.8 years from the present all of the above listed
radionuclides will have experienced at least five half lives.
At 500 years past closure (assuming a date of 2018 for closure or completion of 100 Area
remediation) the following number of half lives and percent reductions in radioactivity will have
been realized.
o Cesium-137 ~r6.5 Half Lives - 99.998 % Reduction
o Cobalt-60 94.3 Half Lives - Essentially 100% Reduction
o Europium-152 37.0 Half Lives - Essentially 100% Reduction
o Europium-154 64.1 Half Lives - Essentially 100% Reduction
o Strontium-90 17.3 Half Lives - 99.999 % Reduction
COMMENT 22. (a). A description of how the conduct of the interim remedial measures impacts
the long term cleanup goals for the site should be accomplished.
(b). For example, are the high priority sites not currently being considered for interim remedial
measures being delayed indefinitely ?
(c). When and how will these sites be characterized and evaluated for future action ?
(d). Specifically sites 116-B-9,116-B-10,116-H-2 and the two unnamed deferred sites at D Area
are high priority sites which were dropped from consideration as IRM candidates without
explanation. Planning should be conducted for those sites.
RESPONSES.
a). The interim remedial measures are expected to be consistent with the long term cleanup goals
for the site. The Hanford Past Practices Strategy designates a "bias for action" to proceed with
cleanup as quickly as possible. The interim remedial measures selected in this ROD are one way
of proceeding expeditiously with cleanup.
b). No, sites are not being delayed indefinitely. The sites being addressed in this action are in
response to stakeholders concerns that sites with the highest potential for adverse impact to the
Columbia River be addressed first. The TriParties are discussing the most expedient methods to
finalize cleanup decisions for all of the remaining waste sites in the 100 Area.
c). The TriParties are discussing the most expedient methods to finalize cleanup decisions for all
of the remaining waste sites, including the remaining high priority sites, in the 100 Area. A
decision on how to best proceed is expected this fall.
d). As noted in the focus sheet distributed with the proposed plans, those sites were reconsidered
by the TriParties and are included in this ROD for remediation.
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COMMENT 23. No action is not an acceptable alternative for 116-B-12,116-D-9 and 116-H-4.
RESPONSE. The 166-D-9 site is included in this ROD fonremediation. The TriParties are
proposing that action be taken first at sites that pose the highest potential for adverse impact to
the Columbia River. The 116-B-12 and 116-H-4 are not considered to be within this group of
sites for interim action. These sites will need to be further evaluated to determine what action is
necessary, if any, to complete a final action.
COMMENT 24. The 116-B-12 Seal Pit Crib should be characterized to resolve apparent
conflicting information in the feasibility study and the proposed plan. The FS recommends
institutional controls while the proposed plan recommends no action. Another approach would
be to include the site as an IRM and characterize and remediate in one process.
RESPONSE. There is no inconsistency between the Focused Feasibility Study, Revision 0 and
the Proposed Plans regarding the recommended alternative "No Action." In an earlier draft of
the Focused Feasibility Study, seal pit cribs were recommended for institutional controls. In the
final draft, this was changed to no interim action because contaminant levels in the cribs were not
detected above preliminary remediation goals. It is acknowledged that before a final Record of
Decision can be written for this site, additional evaluation will be required.
COMMENT 25. The 116-D-9 Crib should be included as a candidate for an IRM.
RESPONSE. As noted above, the 116-D-9 site is included in this ROD for remediation.
COMMENT 26. No action was recommended at the 116-H-4 Crib, due to previously conducted
removal actions. Has the site been characterized to assure remaining contamination levels are
below the residential risk levels ? If so, the relevant supporting information should be presented.
If not, site-specific information should be used to guide cleanup actions.
RESPONSE. This site was excavated in 1960 and the material was deposited in the 118-H-5
Burial Ground (Thimble Pit). Additional characterization of the site was not conducted after the
contamination was removed. It is acknowledged that before a final Record of Decision can be
written for this, site, additional evaluation will be required.
COMMENT 27. Please provide an estimate of the expected waste volumes compared to the
expected volume reduction by treatment; the acreage of land to be impacted by the removal,
treatment and disposal activities, and the area of land to be revegetated under the proposed
alternatives.
RESPONSE. A preliminary estimate has been made that 1,295,936 cubic yards of
contaminated material exists at the high priority liquid radioactive effluent disposal waste sites.
The percent volume reduction by treatment is not precisely known at this time. Preliminary
information from soil washing treatability studies indicates that about 40 percent of Hanford soils
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are treatable by soil washing. Of that 40 percent, approximately 85 percent volume reduction can
be achieved. Based on the preliminary volume estimate, this would translate into approximately
518,375 cubic yards of soil eligible for soil washing, and up to a 440,618 cubic yard reduction
via soil washing. This projection would leave approximately 855,318 cubic yards for disposal.
Using information on excavated volume dimensions presented in Attachment 1 to Appendices E,
F, and G to the Focused Feasibility Study, the approximate area to be affected by removal
activities at high priority liquid waste disposal sites discussed in Proposed Plans for the 100-BC-
1,100-DR-l, and 100-HR-l Operable Units can be estimated as follows:
D 100-BC-l Operable Unit: 56 Acres
D 100-DR-l Operable Unit: 43 Acres
D 100-HR-l Operable Unit: 11 Acres
It should be noted that virtually all cleanup activities will take place in areas that have been
previously disturbed during the construction period for reactors and their support facilities. The
area required to support treatment is not known, but is expected to be small. The area to be
affected by waste management activities at the Environmental Restoration Disposal Facility,
where disposal will occur, is 4.1 square kilometers (1.6 square miles).
Similarly, the total area to be revegetated has not been determined. Development of mitigation
measures, such as re vegetation planning, will be initiated as part of remedial design efforts
following the Record of Decision.
COMMENT 28. Provide a more detailed description of the residential scenario used to calculate
the risks. Risk scenarios should include Yakama Nation members uses of the site, and exposure
through food grown on the land, or ingestion of plants, fish and wildlife.
RESPONSE. The QRA's evaluated four exposure pathways (external exposure to
radionuclides, inhalation of suspended dust, soil ingestion, and inhalation of volatile organics
from soils) to calculate risks under a residential scenario. Those estimated risks were in turn
used to determine sites that would be selected for interim remedial actions. A complete
description of the risk assessment methodology, assumptions and input parameters are presented
in the 100-BC-l, 100-DR-l and 100-HR-l QRA Reports.
The residential scenario used for developing radionuclide cleanup level of 15 mrem/year
considers the following pathways of exposure: external exposure to radionuclides, inhalation of
suspended dust, soil ingestion, ingestion of plants, and ingestion of products (meat and milk)
from animals consuming feed raised in soils with residual radionuclides. Assumptions used to
estimate potential exposure consider daily contact with radionuclides in soil, and ingestion of
plant and animal products comparable to a rural residence.
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Protection offish in the Columbia River is addressed in the cleanup goals designed specifically
to protect groundwater and the Columbia River.
COMMENT 29. If any of the proposed actions is known at this time to have significant impact to
ecological and cultural resources, it should be addressed now and considered in the evaluation of
alternatives and the selection of remedy.
RESPONSE. No cultural resources are expected to be impacted by the cleanup actions
addressed in the Proposed Plans. All work areas and ancillary support areas will be placed on
previously disturbed ground and will be confined to the waste sites and/or to identified support
areas. Because most of these areas have been previously disturbed, significant ecological
impacts are not anticipated as a result of remedial actions. Methods to avoid and/or minimize
impacts to cultural and ecological resources will be taken into account during remedial designs.
Remedial design also will include surveys of sites for cultural and natural resources to assure that
disturbances of identified resource areas are minimized to the extent possible. Known cultural
and historic sites are discussed in Section V of the ROD.
COMMENT 30. Since the sites lie in traditional Native American wintering grounds, a plan
should be in place to assure burial sites are not impacted during implementation of cleanup.
RESPONSE. The remedial actions scheduled for 100-BC-1,100-DR-1, and 100-HR-1 will
take place in areas removed from known burial sites. Also, the waste sites are located in
sediments (i.e., flood plain gravel) which have not demonstrated burial sites in the past. Known
cultural and historic sites are discussed in Section V of the ROD.
No plan can assure that isolated or random burial sites will not be disturbed. However, to reduce
the likelihood of impacts, Native American cultural resource staff will be given the opportunity
to visit the project sites in advance of final site layout design. ERC cultural staff will coordinate
field visits in a similar manner as for the 116-C-l Trench prior to the 100-BC-1 Demonstration
Project. As a result of field inspections, ERC cultural resource specialists and Native American
monitors may be present to observe initial ground breaking activities undertaken in support of
these projects. Activities beyond initial ground breaking may also be monitored as determined
appropriate by the participants. Should a burial be discovered at any time, NAGPRA procedures
will be implemented.
COMMENT 31. A list of contaminant specific cleanup levels should be provided.
RESPONSE. These are provided in Tables 25, 26, and 27 of the ROD.
COMMENT 32. Does the risk scenario to be used for cleanup levels assure that future Native
American users of the site will not be at risk by residual contamination when using the site in the
traditional manner ?
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RESPONSE. The residential exposure scenario used to develop cleanup levels in soil reflects
traditional Native American uses of the site to the extent that, there would be similarities in
frequency and duration of time spent at a site, rates of contact with soil, and ingestion rates of
plant and animal products. The food chain models and assumptions used to estimate uptake of
contaminants from soil to plants and animals are sufficiently general that they likely predict
similar rates of uptake for native plants (for example, the models calculate radionuclide uptake
into fruits and edible roots without distinguishing between different plant species). Similarly,
estimated uptake of radionuclides by plant eating animals would be similar regardless of whether
the animal was free-range cattle or deer. While the models probably do hot fully reflect all uses
of a site, they provide an indication of the magnitude of exposure that may be common to the
residential scenario and traditional Native American uses of a site.
COMMENT 33. Do the cleanup standards provide adequate protection of the habitat for native
species, including food and medicines ?
RESPONSE. Please see the response to Comment 32 above.
COMMENT 34. Cleanup goals should be protective of native uses such as hunting, fishing,
gathering, and pasturing of livestock.
RESPONSE. Please see the response to Comment 32 above.
COMMENT 35. Provide a basis, including references, for the proposed 15 mrem standard for
cleanup of the radionuclides in the plan.
RESPONSE. The proposed standard will limit radiation doses from contaminated sites to 15
mrem/year above natural background levels for soils. The 15 mrem/year proposed standard
corresponds to a incremental cancer risk of 3 x 10"4, based on the following assumptions:
D The site would be used in the future for residential use.
D Residents are potentially exposed for 350 days/year for 30 years.
D "All potential exposure pathways" are considered in assessing exposure to future
residents.
The rationale for the 15 mrem/yr standard is that it falls within the range of other radiation
protection standards promulgated or proposed by EPA, NRC and others. Prior radiation
protection standards correspond to incremental cancer risks ranges of 10'2 to 10"4. The 15
mrem/year standard is applicable to an entire site, including soils, structures, surface water and
air. Cleanup standards for groundwater are considered separately from other media; cleanup of
soils to protect groundwater is based on achieving drinking water MCL's.
Sources: EPA. 1994. 40 CFR 196, Environmental Protection Agency Radiation Site
Cleanup Regulation, Notice of Proposed Rulemaking;
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EPA. 1994. Issues Paper on Radiation Site Cleanup Regulations. Office of
Radiation and Indoor Air, Washington, DC.
NRC. 1994. 10CFRPart20. Notice of Proposed Rulemaking.
COMMENT 36. Discuss the models which will be used to determine if remaining soil
contamination will impact ground water such that contamination could exceed Maximum
Contaminant Levels under the Safe Drinking Water Act.
RESPONSE. A simple leaching/dilution model, known as the Summer's model has been used
to estimate concentrations hi soil corresponding to MCL's in groundwater. The Summer's model
is a steady-state one-dimensional analytical model which assumes an infinite constant
contaminant source, with uniform unchanging contamination throughout the vadose zone. The
cleanup levels developed by this model are conservative, because they neglect the time required
for contamination to migrate to the water table. Under ambient site conditions, contaminants
could re-adsorb to soil particles while traveling to the groundwater, and radionuclide decay
would occur during contaminant travel. These processes, which could reduce the amount of
contamination that could enter groundwater from soil, are not considered in the Summer's model.
COMMENT 37. Protection measures for waste that will be stored prior to disposal should be
included. Soil containing hazardous waste should be double contained, incompatible waste
should be segregated, barriers should be in place to prevent inadvertent intrusion, and runoff
collection should be provided.
RESPONSE. All relevant and appropriate considerations for temporary storage facilities will be
addressed during remedial design activities.
COMMENT 38. The documents state that "site specific re-vegetation plans will be developed
during remedial design with input from affected stakeholders". These plans should be provided
as early as possible in the remedial design phase and prior to construction.
RESPONSE. The TriParties will continue to involve affected stakeholders during remedial
design and remedial action activities associated with the development and implementation of
revegetation plans. The revegetation plan for the 116-C-l waste site has been provided to the
Natural Resource Trustees for their input.
COMMENT 39. Though the "Remove/Treat/Dispose " Alternative has been selected for most of
the source areas, the decision point at which the choice to treat or remove has not been defined.
RESPONSE. Treatment will be performed when it is appropriate or required. For purposes of
the Focused Feasibility Study, treatment was identified as appropriate when it is shown to be
cost-effective. Other factors may affect the appropriateness of treatment in the future such as
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situations where contaminant levels exceed waste disposal acceptance criteria. Additionally, a
treatability variance could be required if Land Disposal Restricted contaminants under the
Resource Conservation and Recovery Act are encountered.
COMMENT 40. Are ARAR waivers being considered ?
RESPONSE. No, at this time no ARAR waivers have been requested or are under consideration.
If any waivers are considered in the future, the public will be notified.
COMMENT 41. The general sampling and decision making strategy which will be used to
determine if cleanup goals at these IRM sites should be discussed.
RESPONSE. The remedial design shall define the specific sampling strategy and decision
making process to demonstrate achievement of cleanup goals. The sampling and analysis plan
shall define items such as the constituents, level of analysis, and sampling protocol. A
significant portion of the sampling will be based on field screening analyses with limited off-site
laboratory analyses. The data gathered through the sampling effort will support the decision
making process.
COMMENT 42. Since equipment will be mobilized for these remedial measures, the Department
of Energy may wish to consider performing environmental investigation of the sites not
considered for IRM's at this time due to lack of information. Such characterization will provide
useful information for planning future cleanup.
RESPONSE. DOE plans to conduct additional evaluation, field characterization, and
engineering activities, as appropriate, as part of remedial design and remedial action. This is
considered an important part of planning future cleanup.
COMMENT 43. DOE announced that the public comment period for this plan to begin on June
26,1995 and ending on August 9,1995; however, the correspondence informing the Nez Perce
Tribe of the plan was contemporary with the release for public comment. The government-to-
govemment consultation period is 30-45 days prior to public review. Why was the Nez Perce
Tribe not consulted prior to this public comment period ?
RESPONSE. DOE is continuing dialogue with the Nez Perce and other affected Native
American Tribes in order to maintain and improve methods of communication for Hanford site
activities.
COMMENT 44. The 100-HR-1 Focused Feasibility Study list chrysene as a contaminant of
potential concern for the 116-H-l Process Effluent Trench, but Table 1 of the Proposed Plan does
not list it for that site.
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RESPONSE. Table E2-5 of the 100-HR-1 Focused Feasibility Study incorrectly lists chrysene
as a contaminant of potential concern for the 116-H-l Process Effluent Trench. Table E2-7 in
the Focused Feasibility Study identifies the allowable level for chrysene in soil. This value is
higher than the concentration of chrysene present at the 116-H-l Process Effluent Trench. The
Proposed Plan is correct in not listing chrysene as a contaminant of potential concern.
COMMENT 45. The costs referenced the 100-HR-1 Operable Unit Focused Feasibility Study
Report appear to contain double billing, if not triple billing, for services. Billing by both the
Environmental Restoration Contractor and the Fixed Price Contractor for "Monitoring, Sampling
and Analysis" appears to be a double billing. The listing of separate charges for "Subcontractor
Material Procurement Rate", "Project Management/Construction Management", "General &
Administrative/Common Support" all by the Environmental Restoration Contractor is essentially
double/triple billing for similar services.
RESPONSE. Billing of the Environmental Restoration Contractor (ERC) and the fixed price
contractor for "Monitoring, Sampling, and Analysis," (headings shown under ANA:02, SUB:02,
and ERC:02) includes different aspects of the process. ANA:02 includes all off-site analyses of
samples. SUB:02 addresses the in situ monitoring of the materials during excavation operations
and the collection of individual soil samples. The final heading, ERC:02, includes the onsite
analysis of samples in a mobile laboratory, Quality Assurance, safety oversight, and support from
health physics personnel. The intent of these activities is to compliment rather than duplicate
one another.
The costs for Subcontractor Materials Procurement Rate, Project Management/Construction
Management, General & Administrative/Common Support" are onsite costs that address the
bidding and procurement of a contractor, management and supervision of the contractor, and
onsite common pool costs, such as emergency health services, dosimetry, fire protection, and
security, respectively. These costs are unique and do not duplicate one another.
The TriParties are continuing their efforts to reduce remedial action costs at Hanford. This
includes reviews of cost estimating assumptions, projections, applying value engineering studies,
and lessons learned from demonstration projects such as the 100-BC-l Expedited Response
Action in order to reduce costs wherever possible.
COMMENT 46. The cost of full scale excavation could be avoided if sites were more thoroughly
characterized.
RESPONSE. The implementation of the observational approach for sites in the 100 Area is
based on a "characterize and remediate in one step approach". This has the potential to incur
excavation costs for some sites that may ultimately be found to be below cleanup goals.
However, this cost is partially offset by the cost of characterization that may not produce
sufficient information. It is believed that it is cost effective to proceed with remediation by
integrating the lessons learned in future remedial planning efforts. For large volume sites that
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represent the majority of the estimated cleanup costs, additional initial characterization made be
made through rapid, cost-effective technologies such as cone penetrometer screening for
radionuclidcs.
COMMENT 47. Dust suppression and airborne releases will need to be addressed during
remedial actions.
RESPONSE. Dust suppression will be addressed during remedial design and remedial action
activities.
COMMENT 48. Clean dirt from excavations should not go to the ERDF.
RESPONSE. Clean dirt from excavations will not go to the ERDF. It will be used to backfill the
excavated areas.
COMMENT 49. Leaving wastes in place will not meet the goal of "unrestricted use" for the 100
area. Activities such as agricultural use would be precluded.
RESPONSE. The cleanup goals developed for the proposed remedial actions do not currently
take irrigation into consideration. In the event irrigation occurs hi the future that could cause
additional releases of chromium, the effectiveness and degree of protection provided by the
remedy would need to be re-evaluated.
COMMENT 50. How will "how clean is clean" be determined ? Potential impacts to fish in the
Columbia River should be factored into this decision.
RESPONSE. The remedial action goals specified in the proposed plans are presented as
specific cleanup levels in Tables 25,26, and 27 of the ROD. Cleanup levels are specific,
quantifiable values used to guide the implementation of remedial actions, and to measure the
effectiveness of remedial action in achieving protection of human health and the environment.
Cleanup levels are used to define the extent of contamination in soil, guide remedial
design/remedial action (RD/RA) activities, and determine when remedial action is complete at a
site. Achievement of quantifiable cleanup levels will be demonstrated through a combination of
field screening methodologies and confirmational sampling with more rigorous quality assurance
and quality control methods. One of the remedial action goals is to achieve ambient water
quality criteria for protection of aquatic organisms (including fish) in the Columbia River.
COMMENT 51. Groundwater monitoring should be a component of the 100 Area cleanup
actions.
RESPONSE. Ongoing groundwater monitoring programs will be continued during cleanup of
the 100 Areas. The need for any additions and/or modifications to the existing monitoring
network will be evaluated during remedial design and remedial action activities.
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COMMENT 52. The Insitu Vitrification Technology (ISV) was not given a fair and accurate
consideration in the feasibility studies for the 100 Area.
RESPONSE. During preparation of the Focused Feasibility Study, an exhaustive literature
search was conducted for in situ vitrification and all other technologies considered. In all cases,
the most recent published information that was available and that had been approved by the Tri-
Parties was used to objectively compare technologies. The comparative evaluations clearly show
that use of in situ vitrification is not compatible with the stated goal to not limit future uses of
100 Area land because it would not meet ARAR's and it is not consistent with potential final
actions and land uses in the 100 Areas. In addition, see the response to Comment 55 below.
COMMENT 53. Geosafe was not requested to provide input into the feasibility studies for the
100 Area.
RESPONSE. The avenue for Geosafe to provide input is through the public comment period, as
has been done. See the response to Comment 55 below.
COMMENT 54. Factors such as the CERCLA preference for treatment, permanence, volume
reduction and the use of innovative technologies were purposely given diminished importance in
the 100 Area feasibility studies through the use of low weighting factors.
RESPONSE. A lower weighting factor was used for the treatment criteria in the evaluation of
alternatives. However, the use of this weighting factor did not have a significant impact to the
results of the comparative analysis. For example, if the results using the low weighting factor
(0.5) were to be compared to results using a full weight (1.0) for the treatment criteria, both
evaluations result in the alternatives being scored relatively the same with respect to each other.
Innovative technologies were considered in the Focused Feasibility Study process, and one such
technology, in situ vitrification, was carried through the detailed analysis. In situ vitrification
was judged to be not compatible with the goal to not limit future uses of 100 Area land because it
would not meet ARAR's, and it is not consistent with potential final actions and land uses in the
100 Areas. Therefore, a more conventional technology, which does not have the limitations of in
situ vitrification, was identified as the preferred alternative.
COMMENT 55. Several specific comments on language in the feasibility studies were
submitted by Geosafe regarding the ISV technology and its application. These were submitted to
clarify areas in 100 Area documents where Geosafe contends there are inaccuracies, and to
bolster the argument that ISV should be the selected remedy for the 100 Area waste sites.
RESPONSE. The specific comments on areas in the documents where Geosafe contends there
are technical inaccuracies are not individually addressed in this responsiveness summary.
Rather, the comment letter is attached herein, and therefore has become part of the administrative.
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record for the site. Furthermore, the following discussion is presented in response to the Geosafe
letter.
The Geosafe Company was involved in technology evaluations for application of ISV at 100
Area waste sites. Pilot scale treatability studies were performed at selected waste sites at 100-
B/C Area. To the extent that Geosafe is in possession of additional technical information, than
that which was evaluated by the TriParties and is presented in the feasibility studies, Geosafe was
given ample opportunity to provide that information and did not to do so.
Furthermore, the application of ISV to 100 Area waste sites would not meet the goal of
unrestricted use for the area, since deed restrictions would be required to prevent intrusion into
areas where metals and radionuclides were contained in a vitrified mass.
Finally, many of the sites would require significant additional characterization than has been
undertaken in order to-potentially apply the ISV technology. The selected remedy combines
characterization steps with the remediation process for the waste sites in the 100 Area, thereby
eliminating the need for additional, costly characterization. The selected remedy is considered to
best meet the threshold criteria and provides the best balance overall of meeting the CERCLA
nine criteria.
IV. REMAINING CONCERNS. This section discusses community concerns that the agencies
should be aware of as they prepare to undertake remedial designs and remedial actions at the 100
Area Operable Units.
Commentors indicated a strong desire for focusing of resources on more cleanup activities and
less on studies. An emphasis on restoration of natural habitat and minimizing disturbance of
cultural and ecological resources in areas disturbed by remedial actions was made by several
commentors.
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