PB96-964611
EPA/ROD/R10-96/143
August 1996
EPA Superfund
Record of Decision:
Hanford 300 Area (USDOE), 300-FF-l and
300-FF-5 Operable Units, Benton County, WA
7/17//1996
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DECLARATION OF THE RECORD OF DECISION
SITE NAME AND LOCATION
USDOE Hanford 300 Area
300-FF-l and 300-FF-5 Operable Units
Hanford Site
Ben ton County, Washington
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected final remedial and interim remedial actions for
portions of the USDOE Hanford 300 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 Superfund Amendments and
Reauthorization Act of 1986 (SARA), and to the extent practicable, the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP). This decision is based on the
administrative record for this site. *'
The Washington State Department of Ecology (Ecology) concurs with the selected remedies.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this site, if not addressed by
implementing the response actions selected in this Record of Decision (ROD), may present an
imminent and substantial endangerment to public health, welfare, or the environment.
DESCRIPTION OF THE SELECTED REMEDIES
This ROD addresses actual or threatened releases from the wastes sites in the 300-FF-l
Operable Unit and the groundwater in the 300-FF-5 Operable Unit. 300-FF-l and 300-FF-5
are two of the three operable units that comprise the USDOE Hanford 300 Area National
Priorities List site. The third operable unit (300-FF-2) consists of the remaining waste sites in
the 300 Area NPL site and any associated groundwater that is not part of 300-FF-5. Actual or
threatened releases from the waste sites and the groundwater in 300-FF-2 will be addressed in
a future ROD. The major components of the selected final remedy for 300-FF-l include:
Removal of contaminated soil and debris;
Disposal of contaminated material at the Environmental Restoration Disposal
Facility;
Recontouring and backfilling of waste sites, followed by revegetation;
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• Institutional controls to ensure that unanticipated changes in land use do not
occur that could result in unacceptable exposures to residual contamination.
The selected remedy for 300-FF-5 is an interim remedial action that involves imposing
restrictions on the use of the groundwater until such time as health-based criteria are met for
uranium, trichloroethene, and 1,2-Dichloroethene. This is an interim action because there are
other constituents (e.g., tritium) which are migrating into 300-FF-5 that have not yet been
fully addressed and because a portion of 300-FF-5 is overlaid by uncharacterized waste sites in
300-FF-2. A final remedial action decision for 300-FF-5 will be made after these issues have
been addressed. The selected interim remedy includes:
• Continued monitoring of groundwater that is contaminated above health-based
levels to ensure that concentrations continue to decrease;
• Institutional controls to ensure that groundwater use is restricted to prevent
unacceptable exposures to groundwater contamination;
DECLARATION
The selected remedies are protective of human health and the environment, comply with
Federal and State applicable or relevant and appropriate requirements directly associated with
these remedial actions, and are cost-effective. These remedies utilize permanent solutions and
alternative treatment (or resource recovery) technologies, to the maximum extent practicable
for this site. However, because treatment of the principal threats of the site was not found to
be practicable, these remedies do not satisfy the statutory preference for treatment as a
principal element.
Because these remedies will result in hazardous substances remaining on-site above health-
based levels, a review will be conducted within five years after commencement of remedial
action to ensure that the remedies continue to provide adequate protection of human health and
the environment.
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Signature sheet for the Record of Decision for the USDOE Hanford 300-FF-l and 300-FF-5
Operable Units Remedial Actions between the United States Department of Energy and the
U;;i:cJ Slate;; Environmental Protection Agency, \vith concurrence by the Washington State
Department of Ecology.
7//7
). Wagoner y Date
lager, Richland Operations
United States Department of Energy
in
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Signature sheet for the Record of Decision for the USDOE Hanford 300-FF-l and 300-FF-5
Operable Units Remedial Actions between the United States Department of Energy and the
i-p erf or*
....
Department of Ecology.
Cjiuck Clarke y
.egional Administrator, Region 10
United States Environmental Protection Agency
IV
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Signature sheet for the Record of Decision for the USDOE Han ford 300-FF-l and 300-FF-5
Operable Units Remedial Actions between the United States Department of Energy and the
UIliLCO OUUCb JJ/ii v•ii^muc-mai i" iuicCuvJii / v^unu), With CuiiCUi i'ciiCC by UiC \\aslungtOll Suite
Department.of Ecology.
_
Michael A. Wilson Date
Program Manager, Nuclear and Mixed Waste Program
Washington State Department of Ecology
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TABLE OF CONTENTS
DECLARATION OF THE RECORD OF DECISION
DECISION SUMMARY 1
SITE NAME, LOCATION, AND DESCRIPTION 1
SITE HISTORY AND ENFORCEMENT ACTIVITIES 1
HIGHLIGHTS OF COMMUNITY PARTICIPATION 11
SCOPE AND ROLE OF RESPONSE ACTION WITHIN SITE STRATEGY .... 13
SUMMARY OF SITE CHARACTERISTICS 14
SUMMARY OF SITE RISKS 36
REMEDIAL ACTION OBJECTIVES 49
DESCRIPTION OF ALTERNATIVES 52
SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 57
SELECTED REMEDIES 61
STATUTORY DETERMINATIONS 63
DOCUMENTATION OF SIGNIFICANT CHANGES 66
RESPONSIVENESS SUMMARY ' 67
VI
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DECISION SUMMARY
T cTrn^ \T A n./fT? T OO.A TTOVT A MT> T>T?Q TW
The U.S. Department of Energy's Hanford Site is a 560-square-mile federal facility located in
southeastern Washington along the Columbia River (see Figure 1). The region includes the
incorporated cities of Richland, Pasco, and Kennewick (Tri-Cities), as well as surrounding
communities in Benton, Franklin, and Grant counties. 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.
The 300 Area, which encompasses approximately 1.35 sq km (0.52 sq mi), is adjacent to the
Columbia River and approximately 1.6 km (1 mi) north of the Richland city limits. The
300 Area is generally level, with a steep embankment dropping to the river. The waste sites in
300-FF-l are not near any wetlands and are not within the 100-year floodplain. The 300 Area
began as a fuels fabrication complex in 1943. Most of the facilities in the area were involved
in the fabrication of nuclear reactor fuel elements. In addition to the fuel manufacturing proc-
esses, technical support, service support, and research and development related to fuels
fabrication also occurred within the 300 Area, In the early 1950's, the Hanford Laboratories
were constructed for research and development. As the Hanford Site production reactors were
shut down, fuel fabrication in the 300 Area ceased. Research and development activities have
expanded over the years. The 300 Area contains a number of support facilities, including a
powerhouse for process steam production; a water intake and treatment system for potable and
process water; and other facilities necessary for research and development, environmental
restoration, decontamination, and decommissioning.
EL SITE HISTORY AND ENFORCEMENT ACTIVITIES
The Hanford Site was listed on the National Priorities List (NPL) in November 1989 under the
Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA)
as amended by the Superfund Amendments and Reauthorization Act of 1986 (SARA). The
Hanford Site was divided and listed as four NPL Sites: the 100 Area, the 200 Area, the 300
Area, and the 1100 Area.
In anticipation of the NPL listing, the U.S. Department of Energy (DOE), the U.S.
Environmental Protection Agency (EPA), and the Washington State Department of Ecology
(Ecology) entered into the Hanford Federal Facility Agreement and Consent Order (known as
the Tri-Party Agreement) in May 1989. 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.
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 November 1989 as four sites (the
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APPROXIMATE
3 KILOMETERS
•r
2 MILES
Legend
300-FF-2 Operable Unit
300-FF-1 Operable Unit
300-FF-5 Operable Unit
E9508079.1b
1\
Hanford Site
Boundary
100
s
\ Washington /
L ^ \ ~"^\ \ \V
1 \ i i 1
| I •-- r — ; — - - -~1 — - -^
1 200-West i I 1 200-East
A Area \ [^ |<] Area
— M — \ :- \ \
V'"x \ XA
xEnvironmental NXX
i Restoration ' XN
!___ Disposal }
V \ Facility /
Richland
Figure 1. Hanford Site Map.
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100 Area, the 200 Area, the 300 Area, and the 1 100 Area). Each of these areas was further
divided into operable units, which are groupings of individual waste units based primarily on
. , . -
Cli CtX CUiU V^WiiUiiVJii
operable units: 300-FF-l, 300-FF-2 and 300-FF-5 (see Figure 2). The 300-FF-l Operable
Unit addresses contaminated soils, structures, debris, and burial grounds. The 300-FF-2
Operable Unit is as generally depicted in Figure 2 and includes contaminated soils, debris,
burial grounds, and groundwater. The 300-FF-5 Operable Unit is as depicted in Figure 2 and
addresses the groundwater beneath 300-FF-l and part of 300-FF-2.
The 300-FF-l Operable Unit covers an area of approximately 47.4 ha (1 17 acres) and contains
many of the current and past 300 Area liquid waste disposal units. The 300-FF-l Operable
Unit is bounded on the east side by the Columbia River and on the north, south, and west sides
by the 300-FF-2 Operable Unit.
The waste sites in 300-FF-l have been divided into two categories: process waste sites and the
burial ground. The process waste sites received primarily liquid wastes, and the burial ground
received primarily solid wastes. Table 1 provides a summary of the physical characteristics of
these sites.
300-FF-l Process Waste Sites. Thfe process waste sites are the South Process Pond, the
North Process Pond, the Process Trenches, the Process Trenches Spoils Pile, the Process
Sewers, the Sanitary Tile Field and other sanitary sewage waste sites, the Ash Pits, the Filter
Backwash Pond, the Retired Filter Backwash Pond (located over part of the South Process
Pond), the North Process Pond Scraping Disposal Area, the 300-3 Aluminum Hydroxide site,
and Landfills la, Ib, Ic, and Id. Landfills la, Ic, and Id were originally grouped with the
Burial Grounds in the remedial investigation and feasibility study (RI/FS). After further
evaluation, however, it was determined that the remedy for the process waste units also will
apply to the landfills for the following reasons: the landfills are small in area and volume
when compared to the burial ground, Landfills Ib and Id are co-located within part of the
North Process Pond Scraping Disposal Area, and Landfills la and Ic are near the North
Process Pond and the Columbia River.
The South Process Pond is an inactive, unlined surface impoundment in the southern
area of 300-FF-l. The South Process Pond was the first disposal facility for liquid
process wastes in the 300 Area. These liquid wastes contained uranium, copper, and
aluminum, as well as traces of other contaminants. The pond also received slurried ash
from the coal-fired power house. It was built in 1943 and was operated until 1975,
when it was replaced by the Process Trenches. This pond was originally a single large
infiltration basin with the inlet in the southwest corner. In 1948, after the North
Process Pond was constructed, the inlet was moved to the northwest corner. In 1951, a
dike was constructed across the south end of the pond to form the eastern Ash Pit and
the now-retired filter backwash pond (now called the Retired Filter Backwash Pond).
Later, dikes were added to route the flow through the pond. The inlet was in the
northwest corner, from which the wastewater flowed through three small settling basins
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-N-
Hanford Site
Boundary
Legend
300-FF-2 Operable Unit
300-FF-1 Operable Unit
V77A 300-FF-5 Operable Unit UAPPROX,MATE
E9604048.8
Figure 2. 300 Area Operable Units.
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Table 1. 300-FF-l Waste Sites.
(Sheet 1 of 3)
Facility
Description/Designation
Years of
Service/Status
Waste
Construction
South Process Pond
(316-1)
1943-1975
Inactive
Process wastes
Water treatment filter backwash
Approximately 11 acres in size consisting of
three small settling basins separated by 9-fl high,
16- to 20-ft wide dikes; two larger infiltrat;on
basins separated by 9-ft high by 100-ft wid 3
dike.
North Process Pond
(316-2)
1948-1975
Inactive
Process wastewater
Slurried coal fly ash
Approximately 9 acres in size surrounded by
10-ft high and 15-ft wide dike; pond is divided
into three small settling basins and one larg er
infiltration basin separated by 15-ft high and
12-ft wide dikes.
North Process Pond
Scraping Disposal Area
(618-12)
1948-1964
Inactive
Sludge from North Process Pond
Coal fly ash
400 ft by 200 ft by 8 ft deep; covered with ashes.
Process Trenches (316-5)
1975-1994
Inactive
- Process wastewater
Process Trench Spoils
Area
1991
Inactive
Disposal location for sediments
excavated from the active
portions of the east and west
trenches.
Two parallel trenches each 1,500 ft long and
12 ft deep at the bottom; 150 by 10 ft extension
from slope failure. The excavation activities
removed a total of 10,800 m3 (14,000 yd3) from
the trenches.
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Table 1. 300-FF-l Waste Sites.
(Sheet 2 of 3)
Facility
Description/Designation
Years of
Service/Status
Waste
Construction
Process Sewer System
(within 300-FF-l)
1943.1994
Inactive
Process wastewater (cooling water and
low-level radioactive liquid wastes from
fuels fabrication)
Laboratory wastes
Chemical spills
24-in.-diameter vitreous clay pipe v/ith
gasketed bell and spigot joints. Only
those portions of the process sewer
located within the operable unit are
addressed.
Sanitary Sewer System
(Sanitary Trenches)
Post-1954 to
Present
Active
Sanitary sewage
Septic tank overflow
Cooling water
Small quantities of photographic
chemicals
8-in. clay pipe to septic tanks and two
parallel leaching trenches, each 500 by
12 ft wide; tanks once drained to now
abandoned tile field. Only the portions of
the sanitary sewer located within the
operable unit boundaries are addressed.
Ash Pits
1943-Present
Active
- Slurried coal fly ash
Two pits 15 to 20 ft deep.
Filter Backwash Pond
1987-Present
Active
- Water treatment filter backwash
Single basin 20 to 25 ft deep, with a
synthetic liner which rests on a.concrete
liner/foundation; part of south process
pond 1944-1951. Ash pit prior to use
as Filter backwash pond.
Retired Filter Backwash
Pond (Infiltration Basin
within South Process
Pond)
1975-1987
Inactive
- Water treatment filter backwash
Eastern pit part of south process pond
1944-1951.
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Table 1. 300-FF-l Waste Sites.
(Sheets of3)
Facility
Description/Designation
Years of
Service/Status
Waste
Construction
Landfill la
Unknown
Inactive
Located between Burial Ground 618-5
and the river. Evidence suggests the
area was used for burning debris. Waste
types undetermined, probably from
laboratories.
Several parallel trenches; precise
dimensions unknown.
Landfill Ib
Unknown
Inactive
Located south of Burial Ground 618-5
and bounded by the North Process Pond
perimeter fence. General area identified
as having received wastes. Quantity
unknown.
Undetermined.
Landfill Ic
Unknown
Inactive
Unknown wastes. Located directly east
of the northeast corner of North Process
Pond. Waste was removed during the
remedial investigation.
Undetermined.
Landfill Id
1962-1974
Inactive
Located north of the west end of the
sanitary trenches. Used as burn pit.
Burn pit for miscellaneous debris.
Burial Ground No. 4
(618-4)
1955-1961
Inactive
Miscellaneous uranium-contaminated
materials
Approximately 110,000 ft2, depth
unknown.
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on the west side of the pond into two larger infiltration basins. The pond had no outlet;
water loss was by infiltration and evaporation.
The pond was periodically dredged to improve infiltration after a dike failure in 1948
resulted in a release to the Columbia River. Dredging was discontinued after 1969
when large quantities of sodium aluminate were no longer disposed to the pond. The
dredge spoils were placed on the pond dikes and used elsewhere as fill.
The pond was deactivated in 1975; however, the east infiltration basin continued to be
used for the disposal of filter backwash until late 1986. The dikes separating the
settling basins and the west infiltration basin were partially removed at this time to
provide cover for the pond sludges. The South Process Pond is now dry, and portions
have been covered with soil.
The North Process Pond was constructed in 1948 after a dike failure at the South
Process Pond. The North Process Pond is in the center of 300-FF-l, approximately 91
m (300 ft) west of the Columbia River. The North Process Pond was operated until
1975.
The North Process Pond originally consisted of a single large infiltration basin. This
basin was later subdivided into three small settling basins and one large infiltration
basin. The original three settling basins were replaced by three new basins in
1961/1962. The original basins on the west side of the facility were then used for
sludge disposal. The inlet for the pond was at the southwest corner. The pond had no
outlet; water loss was by infiltration and evaporation.
Lack of infiltration was also a problem for the North Process Pond. The pond was
periodically dredged to improve infiltration from 1948 through 1969. Dredge spoils
were spread on the dikes or spread and covered in the adjacent North Pond Scraping
Disposal Area.
The North Pond Scraping Disposal Area, also known as the 618-12 Burial Ground, is
immediately south of the North Process Pond. This area was used to dispose of pond
sludges. The site has since been covered with coal ash and clean fill.
The Process Trenches are an inactive RCRA treatment, storage, and disposal (TSD)
unit that will be closed pursuant to the Washington Dangerous Waste Regulations
(WAC 173-303). The Hanford Site dangerous waste permit will be modified to
incorporate specific permit conditions for this closure. The Process Trenches consist of
two parallel, unlined trenches that operated from 1975 to 1994. The two trenches,
called the east and west trenches, are separated by an earthen berm. The trenches are
located near the western boundary of the 300-FF-l Operable Unit, approximately 300
m (1,000 ft) west of the Columbia River. The Process Trenches received wastes from
the process sewer system, including the low-level radioactive waste from the 307
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Retention Basins. The trenches did not have outlets; water loss was by infiltration and
evaporation.
By the late 1980's, the process wastewater contained very little uranium. However, the
ground water still had significantly elevated uranium concentrations. The relatively
clean process wastewater was mobilizing uranium previously deposited in the bottom of
the trenches and carrying it to the groundwater. In 1991, DOE performed an expedited
response action (ERA) under CERCLA removal authority at the Process Trenches.
The objective was to move contaminated soils from the south end of the Process
Trenches to the dry north end, thus preventing process wastewater from passing
through the contaminated soil and driving contamination to groundwater.
Approximately 10,800 m3 (14,000 yd3) was moved in the trenches. The more
contaminated materials were placed in a depression in the northwest corner of the west
trench. The less contaminated material was moved to the north end of the trenches,
graded, and covered with a plastic barrier and a layer of clean aggregate. The
contaminated sediments were left within the boundary of the Process Trenches and are
referred to as the Process Trenches Spoils Pile. In 1994, a new effluent treatment and
disposal facility was started up, eliminating discharges to the Process Trenches
completely.
«
The Process Sewer System transferred liquid process wastes to the process ponds and
trenches. Only those portions of the process sewer system located within the operable
unit are included within the scope of 300-FF-l. The system is constructed of vitreous
clay pipe and the trunk sewer diameter is 61 cm (24 in.). The original process sewer
serving the South Process Pond was later modified to serve the North Process Pond.
The process sewers were further modified to serve the Process Trenches, as well as the
307 Retention Basins located in the 300-FF-2 Operable Unit. The portion of the
process sewers serving the North and South Process Ponds was reportedly abandoned in
March 1975. However, documentation of abandonment exists for only the pipe that
fed the southwest corner of the South Process Pond. The as-abandoned condition has
not been identified for the pipe that fed the northwest corner of the South Process Pond
or for the pipe to the North Process Pond.
The Sanitary Sewage Waste Sites handle sanitary sewage from the 300 Area. The
sewage travels through sanitary sewers constructed of vitreous clay pipe. The sanitary
sewers discharge to septic tanks. The septic tanks are periodically cleaned, and the
sludge is disposed of in an adjacent sludge pit. Between 1943 and 1948, the septic
tanks were connected to a tile leach field constructed of perforated clay pipe. The tile
field was replaced by the Sanitary Sewage Trenches, which are still in use. The south
sanitary sewage trench was evidently constructed prior to or during 1948. The north
sanitary sewage trench was constructed in 1952 across portions of the abandoned tile
field. This ROD addresses only those sections of the sanitary sewer located within the
300-FF-l Operable Unit. The Sanitary Sewage Trenches will be taken out of service in
the next few months when the sanitary wastes from the 300 Area will be discharged to
the City of Richland system.
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The Ash Pits received slurried fly ash, which was generated at the 300 Area
powerhouse when coal was burned. Currently, the powerhouse is using No. 6 fuel oil
cUi^l TO ^ '" ".^ i~ U^..^r> r> ,^0,^-n f r^r] T1^ o DV ^ch ^V'oo rlnrTMor! WltVl W^fpf ^ f| (1 dl SChRT^CH
to two ash pits located between the South Process Pond and the 307 Trenches. The
area of the Ash Pits was originally part of the South Process Pond. Presumably, some
contaminated soil and/or sludge from pond operations remains beneath the fly ash. The
Ash Pits originally consisted of a single trench; the trench was divided into the current
configuration around 1960. The Ash Pits often filled up, so sludge was removed and
placed near the river bank or between the north and south process ponds. It is
presumed that, as time progressed, ash was allowed to accumulate at the east end of the
east pit, eventually to the point where the original extent was no longer apparent and
only a limited portion of the ash pit was actually being used.
The Filter Backwash Pond was constructed in 1987 to receive filter backwash from
the 300 Area potable water treatment plant. The backwash contains a high
concentration of alum, which settles in the pond. This facility is located directly east
of the Ash Pits, as currently configured. Prior to 1951, the area was part of the South
Process Pond. The pond has a synthetic liner which rests on a concrete
liner/foundation. After the alum has settled, the water is recycled through the water
treatment plant. »
The Retired Filter Backwash Pond was constructed over a portion of the infiltration
basin of the South Process Pond. When the South Process Pond was retired in 1975,
the infiltration basin was used for disposal of filter backwash. The infiltration basin
operated until 1987.
The 300-3 Aluminum Hydroxide Site was identified during installation of a sump pit
for the 300 Area Treated Effluent Disposal Facility. The site consists of several
horizontal 0.3- to 0.45-m- (1- to 1.5-ft) diameter cedar logs forming a vertical wall
approximately 10 ft high running in a north/south direction. The top part of the wall
slopes downward to the west and the bottom part is vertical. The structure appears to
be resting on a concrete slab at a depth of approximately 3 to 4.5 m (10 to 15 ft). A
white chalky material was found during the excavation. The material was determined
to be aluminum hydroxide; Toxic Characteristic Leaching Procedure analysis indicated
that the material was not a dangerous waste. The constituents in the material were all
below health-based concentrations and the material was determined to be nonhazardous
and was left in place at the site.
Landfills la, Ib, Ic, and Id were identified during a review of aerial photographs.
Radioactive contamination and debris were found on the surface of Landfill la. The
materials appeared to be similar to laboratory wastes. Small amounts of what appeared
to be "yellowcake" (uranium oxide concentrate) were also found. Landfills Ib and Ic
were identified as disturbed or graded areas north of the North Process Pond and near
the Columbia River. Landfill Id was identified as a relatively large burn pit.
Historical records indicate that, although some incidental radioactive materials may
10
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have been buried in Landfill Id, the pit was mainly for paper, wood, paint cans, and
other debris.
Burial Grounds, A variety of solid wastes, some contaminated with uranium, were disposed
in burial grounds or landfills in and around the 300 Area. One burial ground, Burial Ground
618-4, is part of 300-FF-l. The other burial grounds are in 300-FF-2.
Burial Ground 618-4 is located in the northwest corner of the operable unit. It was
used from 1955 through 1961 and is known to contain miscellaneous materials
contaminated with radioactive uranium. In 1979, 20 depleted uranium fuel elements
were found to be improperly discarded near Burial Ground 618-4. An area of
approximately 37 m2 (400 ft2) was found to be radioactively contaminated. The
elements were removed, along with the contaminated surface soils, and disposed of in
the 200 West Area.
300-FF-5. The 300-FF-5 Operable Unit covers an area of approximately 415 ha (1025 acres)
and addresses the groundwater underlying 300-FF-l and part of 300-FF-2. Because
groundwater underlying the 300 Area discharges to the Columbia river, 300-FF-5 included an
assessment of the interaction between the groundwater and the river.
III. HIGHLIGHTS OF COMMUNITY PARTICIPATION
DOE, Ecology, and EPA developed a Community Relations Plan in April 1990 as part of the
overall Hanford Site restoration. This plan was designed to promote public awareness of the
investigations, as well as public involvement in the decision-making process. The plan
summarizes known concerns based on community interviews. Since it was originally written,
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 plan was updated in
1993 to enhance public involvement, and it is currently undergoing an additional update.
The RI/FS reports and the proposed plan for 300-FF-l and 300-FF-5 were made available to
the public in both the Administrative Record and the Information Repositories maintained at
the locations listed below. These documents were offered for a 45-day public comment period
from December 4, 1995 to January 17, 1996. During that time, an extension of the comment
period was requested. The public comment period was subsequently extended to February 9,
1996. The 300 Area Process Trenches Closure Plan and Groundwater Monitoring Plan were
also made available for review.
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ADMINISTRATIVE RECORD (Contains all project documents.)
TJ Js Dc'nnrtTY!^1^ of F
Richland Field Office
Administrative Record Center
2440 Stevens Center Place
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
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
12
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Notices of the public comment period and availability of documents for review were published
in the Seattle Pi/Times, the Spokesman Review-Chronicle, the Tri-City Herald, and the
G/'egonian on December 3, 1995 and again on December 4, 1935. The iiolice also rail
throughout the week of December 3 in the various papers published by the Hood River News.
Additionally, a 2-page focus sheet that summarized the Proposed Plan was mailed on
November 30, 1995 to an "interested in Hanford" mailing list of about 4,700 people. That
mailing list included the members of the Hanford Advisory Board (a citizen/stakeholder
cleanup advisory board), Native American Tribes with reserved treaty rights to Hanford-
related resources, and natural resource trustees. Focus sheets and proposed plans were mailed
to a number of individuals in response to requests during the comment period. The extended
comment period was announced in the Tri-City Herald on January 14, 1996. The proposed
plan and focus sheet identified that a public meeting would be held upon request. No public
meeting was requested. A response to the comments received during the public comment
period is included in the Responsiveness Summary, which is Appendix A of this ROD.
Briefings and discussions were held with the Environmental Restoration Subcommittee of the
Hanford Advisory Board on December 6, 1995 and on January 25, 1996.
This decision document presents the selected remedial actions for the 300-FF-l and 300-FF-5
Operable Units at the Hanford Site in Richland, Washington. The selected remedies are
chosen in accordance with CERCLA'as amended by SARA, and to the extent practicable, the
National Contingency Plan (NCP). The decision for these operable units is based on the
Administrative Record.
IV. SCOPE AND ROLE OF RESPONSE ACTION WITHIN SITE STRATEGY
The cleanup actions described in this ROD address known current and potential risks to human
health and the environment from 300-FF-l. The interim actions for 300-FF-5 described in
this ROD address known current and potential risks to human health and the environment from
the uranium, trichloroethene, and 1,2-Dichloroethene in the groundwater. This ROD does not
address other contaminants (e.g., tritium) that may be present in 300-FF-5 which are reserved
for future actions. These actions are enhanced by the 1991 ERA and the elimination of liquid
waste discharges in the 300 Area. The remedial action at Burial Ground 618-4 will provide
information helpful in selecting remedial actions at the burial grounds in 300-FF-2. This ROD
addresses the contaminated soil and debris in 300-FF-l and the contaminated groundwater in
300-FF-5 described above. This ROD also requires the disposal of excavated contaminated
materials from the 300 Area Process Trenches. The Process Trenches are subject to closure
requirements under RCRA. The closure plan and the specific permit conditions will be part of
the Hanford Site RCRA permit. Actual or threatened releases from the waste sites and the
groundwater in 300-FF-2, and a final remedial decision for 300-FF-5, will be the subject of
future proposed plans and RODs.
13
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V. SUMMARY OF SITE CHARACTERISTICS
A. General Characteristics
The Hanford Site is located in the Pasco Basin, a sediment-filled topographic and structural
basin situated in the northern portion of the Columbia Plateau. The Hanford Site is dominated
by the low-relief plains of the Central Plains physiographic region and anticlinal ridges of the
Yakima Folds physiographic region. The Pasco Basin is bounded on the north by the Saddle
Mountains anticline; on the west by the Umtanum Ridge, Yakima Ridge, and Rattlesnake Hills
anticlines; and on the south by the Rattlesnake Mountain anticline. The Palouse Slope, a
west-dipping monocline, bounds the Pasco Basin on the east. The Pasco Basin is divided into
the Wahluke and Cold Creek synclines, which are separated by the Gable Mountain anticline,
the eastern extension of the Umtanum Ridge. The sediments within the Pasco' Basin are
underlain by the Miocene-age Columbia River Basalt Group, a thick sequence of flood basalts
that covers a large area in eastern Washington, western Idaho, and northeastern Oregon.
Local Geology. The uppermost member of the Columbia River basalts present in the
300 Area is the Ice Harbor Member of the Saddle Mountains Basalt group. Suprabasalt strata
in the 300 Area consist of the 29- to 44-m thick (95- to 145-ft thick) Ringold Formation, the
24- to 35-m (80- to 115-ft) thick Hanford formation, and a thin veneer of surficial deposits.
Sediments from the upper strata of the Ringold Formation within and near the 300 Area are
characterized by complex interstratified beds and lenses of sand and gravel. Ringold
Formation deposits are generally better cemented, calcified, and sorted than those from the
Hanford formation. Ringold strata typically contain a lower percentage of angular basaltic
detritus than do Hanford formation deposits.
Local Hydrogeology. The unconfmed aquifer beneath the 300 Area is composed of two
hydrogeologically distinct formations: the Hanford and the Ringold formations. The Hanford
formation is dominated by pebble to boulder gravels with sandy dominated facies present
locally. Excluding eolian deposits, the vadose zone is composed of the Hanford sands and
gravels. The open framework structure of this formation yields very high hydraulic
conductivities ranging between 3,600 m/day (12,000 ft/day) to 10,000 m/day (32,800 ft/day).
The formation generally has a high porosity and drains rapidly. Though mounding beneath
operating ditches and ponds was observed in the past, no such mounding is known to exist
today. Saturated Hanford formation underlies the North and South Process Ponds and the
Process Trenches and varies between 1.5 to 7.6 m (5 to 25 ft) in thickness. The saturated
Hanford formation generally thickens near the Columbia River and thins to the west. The
partially indurated Ringold Formation underlies the Hanford formation and completely
contains the unconfmed aquifer on the western edge of the operable unit. There is evidence of
several erosional lows in the top of the Ringold Formation that generally extend from west to
east across the formation. The Ringold Formation has much lower conductivities, ranging
from 50 m/day (160 ft/day) to 150 m/day (500 ft/day).
The uppermost confined aquifer occurs in the lower sand and gravel units of the Ringold
Formation and is separated from the unconfmed system by the Ringold lower mud unit. An
14
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upward gradient exists between the confined and the unconfined aquifers, indicating that the
mud unit is locally extensive.
Flow in the unconfmed system is generally toward the Columbia River, and groundwater
eventually discharges to the river through springs and seeps in the river bottom and riverbank.
However, river stage strongly influences both groundwater flow and contaminant exchange
rates between the aquifer and the river. This effect is most pronounced near the river, but is
also observed throughout the operable unit. Gradient reversals, causing flow to move from the
river into the 300-FF-5 Operable Unit, are common and are facilitated by the high
transmissivities measured in the Hanford formation. Daily river stage variations of 1 to 3 ft
are common, and seasonal (long-term) changes of 4 ft have been observed.
The groundwater flow system has a significant impact on the contaminant distribution observed
in the aquifer. Higher groundwater pore velocities, associated with the saturated Hanford
formation found along the river, will quickly flush and naturally dilute contamination
introduced into the aquifer and facilitate its remediation. Contaminants whose movement is
only slightly chemically retarded will decrease with time once potential sources are removed or
contained.
Surface Water, The.Columbia Riv6r is the second largest river in North America, and is 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, and the Hanford Reach
(the free flowing section of the Columbia River beginning at Priest Rapids Dam and ending
just north of 300-FF-l) is now being considered for designation as a National Wild and Scenic
River as a result of congressional action in 1988 (Public Law 100-605). Washington State has
classified the stretch of the Columbia River from Grand Coulee to the Washington-Oregon
border, which includes the Hanford Reach, as Class A, "Excellent". Class A waters are to be
suitable for essentially all uses, including raw drinking water, recreation, and wildlife habitat.
The Columbia River has many uses, including production of hydroelectric power, extensive
irrigation in the Mid-Columbia Basin, and as a transportation corridor for barges. In addition,
the river and islands serve as habitat for a variety of fish and birds. Several communities
along the Columbia River rely on the river for drinking water. Water from the Columbia
River is also the source of drinking water for the 300 Area. In addition, the Columbia River is
used extensively for recreation, including fishing, hunting, boating, sailboarding, waterskiing,
diving, and swimming.
Background Data. Project-specific background soil samples were obtained from six
boreholes located in and near the 300 Area, in areas undisturbed by 300-FF-l Operable Unit
activities. No discernable differences in parameter concentrations exist between the borehole
locations; therefore, all samples were combined to provide a description of the operable-unit-
specific background conditions. Thirty-three samples are available to characterize soil
background in the vadose zone; these include samples collected from the surface to the water
table. Background soil quality is characterized in Table 2.
15
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Table 2. Local Background Soil Concentrations.
Analyte
aluminum
ammonia
antimony
arsenic
barium
beryllium
cadmium
calcium
chloride
chromium
cobalt
copper
cyanide *
fluoride
iron
lead
magnesium
manganese
mercury
nickel
nitrate
nitrite
phosphate
potassium
selenium
silver
sodium
sulfate
thallium
vanadium
zinc
mg/ kg
5190
1.5
11.2
2.2
97.4
.42
.77
8980
400
19.0
12.2
44.2
126
3.4
20900
5.69
4280
333
.1
10.2
5.9
2.2
1.6
980
.26
2.54
367
30.1
1.8
30.9
27.2
16
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Cultural Resources Review. 300-FF-l and 300-FF-5 are located adjacent to the Columbia
River, an area typically associated with high cultural resource potential. Four archaeological
sites of cultural significance have been identified within the operable unit. One site has been
evaluated and determined eligible for placement on the National Register of Historic Places.
According to Section 106 of the National Historic Preservation Act, an eligible site is provided
the same level of protection and associated requirements as a site listed on the National
Register of Historic Places. Human remains have also been identified within the operable
unit. The remains were discovered during the construction of a sewer line and were left
undisturbed and capped with additional soil. The pipeline was constructed above ground, over
the archaeological site. An additional site, considered an isolated find, has been identified
within the operable unit. An isolated find typically represents three or less discrete artifacts
within 10 m (33 ft) of each other. Because more extensive surveys were not performed, the
magnitude is not defined. Those cultural resource reviews conducted to date within 300-FF-l
have been limited to specific project locations. No survey has been conducted over the entire
operable unit. Consequently, any actions undertaken for remediation, or in support of
remediation, will be preceded by a field survey by cultural resource specialists. Because
human remains have already been found within the operable unit, consultation with Native
Americans will take place in the early phases of project design.
An additional six sites are located within 0.8 km (0.5 mi) of the operable unit. Of the six
sites, three are described as "isolates" and consist of limited items uncovered during the
survey. The other three sites are more substantial and are described as traditional-use sites,
such as housepits and fishing camps.
Ecology. No plants or mammals on the Federal list of Endangered and Threatened Wildlife
and Plants are known to occur within 300-FF-l. There are, however, several species (see
Table 3) of both plants and animals that are of concern or are under consideration for formal
listing by the Federal government and Washington State.
The persistentsepal yellowcress (Rorippa colwnbiae) is listed as a Washington State
endangered species and has been found in the riparian zone along the Columbia River within
300-FF-l and 300-FF-5. Two additional plant species that may occur, but have not been
discovered, within the 300-FF-l boundaries are listed as Washington State threatened species.
These species are Hoover's desert parsley (Lomatium tuberosum) and Columbia River
milkvetch (Astragalus columbianus). It should be noted that Washington State designations, in
all cases, are as strict or stricter than the corresponding Federal designations.
Four bird species of concern are noted to occur near 300-FF-l and 300-FF-5. These species
include Swainson's hawk (Buteo swainsoni), Forster's tern (Sterna forsteri), long-billed curlew
(Numenius americanus), and burrowing owl (Athene cunicularid). Of these special animals,
the Washington State Department of Fish and Wildlife classifies the Swainson's hawk and
burrowing owl as "State Candidate" species, and Forster's tern and long-billed curlew as
"State Monitor" wildlife species. The long-billed curlew, until recently, was designated as a
Federal Candidate 3 spqpies. The U.S. Fish and Wildlife Service dropped the Candidate 2 and
3 categories from their listings in February 1996.
17
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Table 3. Candidate Species to the Threatened or Endangered
Identified on the Hanford Site. (Page 1 of 2)
List
Common Name
Molluscs
Birds
Plants
Shortfaced lanx
Columbia pebble snail
Common loon
Swainson's hawk
Ferruginous hawk
Western sage grouse^
Sage sparrow
Burrowing owl
Loggerhead shrike
Northern goshawk^
Lewis' woodpecker^
Long-billed curlew
Sage thrasher
Flammulated owl(b)
Western bluebird^
Golden eagle
Black tern(b)
Trumpeter swan^
Columbia milk-vetch
Columbia yellowcress
Hoover's desert parsley
Northern wormwood(c)
Desert Evening primrose
Shining flatsedge
Dense sedge
Gray cryptantha
Piper's daisy
Southern mudwort
False-pimpernel
Tooth-sepal dodder
Thompson's sandwort
Bristly cryptantha
Robinson's onion
Columbia River mugwort
Stalked-pod milkvetch
Medic milkvetch
Crouching milkvetch
Rosy balsamroot
Palouse thistle
Smooth cliffbrake
Fuzzy -beard tongue penstemon
Squill onion
Scientific name
Fisherola (— Lanx) nuttalli
Fluminicola (= Lithoglyphus) columbiana
Gavia immer
Buteo swainsoni
Buteo regalis
Centrocercus urophasianus phaios
Amphispiza belli
Athene cunicularia
Lanius ludovicianus
Accipter gentilis
Melanerpes lewis
Nunienius americanus
Oreoscoptes montanus
Otus flammeolus
Sialia m.exicana
Aquila chrysaetos
Childonius niger
Cygnus columbianus
Astragalus columbianus
Rorippa columbiae
Lomatium tuberosum
Artemis a campestris borealis var. wormskioldii
Oenothera Caespitosa
Cyperus rivularis
Carex densa
Cryptantha leucophaea
Erigeron piperianus
Limosella acaulis
Lindernia anagallidea
Cuscuta denticulata
Arenaria franklinii v. thompsonii
Cryptantha interrupta
A Ilium robinsonii
Artemisia lindleyana
Astragalus sclerocarpus
Astragalus speirocarpus
Astragalus succumbens
Balsamorhiza rosea
Cirsium brevifolium
Pellaea glabella
Penstemon eriantherus
A I Hum scillioides
Federal00
X(C3)
X(C2)
X(C2)
X(C2)
X(C2)
X(C2)
X(C3)
X(C2)
X
-------
Table 3. Candidate Species to the Threatened or Endangered List
Identified on the Hanford Site. (Page 2 of 2)
Common Name
Scientific name
Federal(a)
State
Insects
Columbia River tiger beetle^
Cinindela colubica
X
Reptiles
Striped whipsnake
Masticophis taeniatus
Mammals
Merriam's shrew
Pacific western big-eared
Pygmy rabbit(c)
Sorex merriami
Plecotus townsendii townsendii
Brachylagus idahoensis
X(C2)
X(C2)
X
X
The following species may inhabit the Hanford Site, but have not been recently collected, and the known
collections are questionable in terms of location and/or identification.
Palouse milkvetch
Few-flowered blue-eyed Mary
Coyote tobacco
Astragalus arrectus
Collinsia sparsiflora
Nicotiana attenuata
S
S
S
*(a) Abbreviations: <
Cl = Taxa for which the Service has enough substantial information on biological vulernability
to support proposals to list them as endangered or threatened species. Listing is anticipated
but has temporarily been precluded by other listing activity.
C2 = Taxa for which current information indicates that proposing to list as endangered or
threatened is possibly appropriate, but for which conclusive data on biological vulnerability
are not available to support listing. The Service will not propose listing unless additional
supporting information becomes available.
C3 = Taxa that were once considered for listing as endangered or threatened, (i.e., in categories
1 or 2) but are no longer current candidates for listing. Such taxa are further subdividied
into three categories that indicate why they were removed from consideration.
S = sensitive, i.e., taxa vulnerable or declining, and could become endangered or threatened
without active management or removal of threats;
Ml =. Monitor group 1. Taxa for which there are insufficient data to support listing as
threatened, endangered, or sensitive.
M2 = Monitor group 2, i.e., taxa with unresolved taxonomic questions.
M3 = Monitor group 3, i.e., taxa that are more abundant and/or less threatened than previously
assumed.
(b) Species reported, but seldom observed, on the Hanford Site.
(c) Probable, but not observed, on the Hanford Site.
Note: The U.S. Fish and Wildlife Service dropped the Candidate 2 and 3 categories from their listings in
February 1996.
19
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B. Nature and Extent of Contamination and Investigative Approach
Investigative Approach. DOE had investigated several of the 300-FF-l waste sites prior to
starting the remedial investigation under CERCLA. The information from these previous
investigations, and available historical information, was used to focus the remedial
investigation. Geophysical and soil-gas surveys were performed over the burial ground prior
to any subsurface sampling. These surveys were used to guide the location of test pits; test
pits were placed in areas where the surveys indicated large concentrations of buried waste or
the possibility of solvents. The process ponds and the process trenches were sampled with
both borings and test pits. The results were used to refine the conceptual site model and the
contaminants of concern list, identify applicable or relevant and appropriate requirements, and
provide an assessment of the risks associated with the sites. The results of the investigation are
described below.
DOE has monitored groundwater in the 300 Area for over 40 years. However, 19 additional
wells were installed to expand the horizontal and vertical coverage. Samples were taken
during well drilling to provide data of documented quality on the site geology and hydrology.
In addition, DOE performed aquifer tests at 5 wells to provide data on aquifer flow properties.
In order to assess impacts to the Colombia River, samples were taken from both the river and
from springs and seeps where groundwater discharges to the river. The results of the
investigations were used to refine the conceptual site model and the contaminants of concern
list, identify applicable or relevant and appropriate requirements, and provide an assessment of
the risks associated with the groundwater. They are described below.
300-FF-l Contamination. In the 300 Area, fuel elements were fabricated by a co-extrusion
process. The fuel elements, or billets, were formed by bonding an aluminum or zirconium
cladding onto a uranium and silicon fuel core. A copper jacket and lubricants were used
during the extrusion process to protect the fuel element. Lubricants were removed using
organic solvents such as trichloroethene (also known as trichloroethylene or TCE). After
extrusion of the fuel elements, nitric acid was used to remove the copper jackets. The uranium
core was chemically milled using copper sulfate, nitric acid, and sulfuric acid. A zirconium
end cap was then brazed on with beryllium. In addition, aluminum fuel spacers from the
100 Area reactors were re-anodized in the 300 Area.
South Process Pond. Surface radiation surveys conducted during the RI identified 3
soil contamination locations near the edge of the South Process Pond and 10 locations
outside the south pond perimeter fence (Figure 3). Most of these locations are north of
the pond and located in what appears to be an enlarged berm. This is the same general
area where records indicate that the dike failed and discharged pond water into the
Columbia River.
Prior to the RI, samples were taken from the South Process Pond in a number of test
pit locations. The data showed that contaminant concentrations decreased with
increasing distance from the pond inlets and also decreased with soil depth.
20
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R-39 to R-44
&R-46
R-14toR-16|~H
R-17to R-2/4
332 Storage
Facility
Areas surveyed at or below
background radiation
Areas surveyed above
background radiation
Area unable to be surveyed
due to high background
radiation associated with
the 340 Complex
Area additionally surveyed
with USRADS
Area not surveyed
300-FF-1 Boundary
Railroad
Fences and Waste Sites
Source: Modified fromTeel and Olsen 1990.
E9604048.3
Figure 3. Surface Radiation Survey Results for 300-FF-l.
21
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Forty-four samples were collected from four locations during the RI. The sampling
locations are shown on Figure 4. A green precipitate layer was found in the 0.3- to
0.6-m (1.5- to 2-ft) interval at SPT-3. Uranium-238 concentrations are greatest
(980 pCi/g) in this near-surface precipitate layer. The concentrations range from 16 to
56 pCi/g at this depth in the other locations sampled. The high concentration at
location SPT-3 correlates with its close proximity to the process pond inlet. In
contrast, location SPT-1 exhibits markedly lower concentrations out in the central
portion of the infiltration pond. The uranium-238 concentrations at location SPT-3
rapidly decrease by orders of magnitude over a short depth interval. Concentrations of
uranium-238 near the water table range between 1.1 and 2.9 pCi/g. Groundwater was
encountered at approximately 9 m (30 ft). At the bottom of the borehole and test pits,
approximately 10 m (35 ft) to 12 m (40 ft) below ground surface, they range from 0.8
to 3.1 pCi/g.
Other radioactive contaminants of concern are present in the waste unit. The highest
concentrations of cobalt-60 were found within the upper 1.5 m (5 ft) at each sampling
location, with the highest (81 pCi/g) found at location SPT-3. Radium-226 and
thorium-228 concentrations in the range of 0.3 to 1 pCi/g are present at all locations
sampled and apparently represent Hanford Site background concentrations.
i
The highest copper concentrations were found in the near-surface soils, with a notably
high concentration of 95,000 mg/kg located in the precipitate layer at location SPT-3.
Copper concentrations below 3 m (10 ft) range between 16 and 83 mg/kg, with the
exception of one location at approximately 5.2 m (17 ft) in SPT-3, where copper was
detected at 520 mg/kg. Chromium exhibits higher concentrations near the surface and
lower concentrations at depth. A chromium peak of 600 mg/kg was found near 0.45 m
(1.5 ft) in location SPT-3. Concentrations at the same depths at locations SPT-1 and
SPT-2 were 43 and 42 mg/kg, respectively. Chromium concentrations at depths
greater than 2 m (6 ft) at all sample locations are less than the operable unit background
upper tolerance limit (UTL) of 19 mg/kg.
Ammonia was detected in 17 of 44 samples taken during the RI. The highest
concentration detected was 90 mg/kg.
Polychlorinated biphenyls (PCBs) were found in the South Process Pond. The highest
concentrations are located at approximately 0.45 m (1.5 ft) below the soil surface;
concentrations range from 5 to 9 mg/kg. PCBs were found at depths greater than 2 m
(6 ft) below the ground surface in only two samples. Concentrations in these samples
were less than 1 mg/kg.
22
-------
\
o
o^
BOOHZO
it • BOOHYS
•B
OOHZ2, BOOHZ3
•BOOHY4
\
Filter Backwash Pond
LEGEND
® Boreholes
py Testpits
• Surface grab samples
Source: Modified from DOE-RL 1993a.
100 METERS
p
bo FEET
E964048.2
Figure 4. Sampling Locations in the Southern Portion of 300-FF-l.
23
-------
North Process Pond. More than 40 soil contamination locations were identified within
a 91-m (300-ft) radius of the North Process Pond during the RI surface radiation survey
(Figure 3). Characterization prior to the RI concluded that the maximum
contamination is located near the pond inlet and at a depth of 5 m (16.5 ft). This
conclusion correlates with results of the RI and indicates that contamination of the
settling basins is more extensive than in the infiltration section of the process pond.
Thirty-eight samples were collected from four locations during the RI. The sampling
locations are shown on Figure 5. The maximum uranium-238 concentration
(900 pCi/g) was at 1.5 m (5 ft) below ground surface at location NPT-1. Pit NPT-1 is
the closest of the RI sampling locations to the pond inlet. A green precipitate layer was
found at this same interval. Similar green precipitate was characterized and identified
as calcite highly enriched with uranium and copper. The uranium-238 concentration
decreases to 120 pCi/g at 2 m (6 ft), then to 34 pCi/g at 3 m (10 ft). The uranium-238
concentrations range between 9 and 20 pCi/g at the remaining depths sampled. Pit
NPT-1 showed consistently higher concentrations than did the other three sample
locations. No uranium-238 concentrations at the other locations exceed 50 pCi/g. The
decreased concentrations in locations distant from the pond inlet adheres to the general
trend of decreasing contamination with distance.
t
The highest cobalt-60 concentration (3.5 pCi/g) was found at 1.5 m (5 ft) in NPT-1.
Cobalt-60 concentrations rarely exceeded 1 pCi/g at any of the other intervals sampled,
regardless of the location in the waste unit. The highest radium-226 and thorium-228
(2 and 3 pCi/g, respectively) concentrations were also found in the first 1.5 m (5 ft) of
NPT-1.
The highest copper and chromium concentrations (41,000 and 550 mg/kg, respectively)
occur within the first 1.5 m (5 ft) below ground surface at location NPT-1, which is
close to the pond inlet. At 6.4 m (21 ft), the contaminant concentrations have
decreased by orders of magnitude to 430 mg/kg for copper and 13 mg/kg for
chromium. The operable unit background UTL is 44 mg/kg for copper and 19 mg/kg
for chromium. Copper concentrations exceed the operable unit background UTL at all
sample locations below 1 m (3 ft) in NPT-1 and below 3 m (9 ft) in 399-1-22.
However, at locations farther from the pond inlet (NPT-2 and NPT-3), copper
concentrations do not exceed the operable unit background UTL below depths of 3.3 m
(lift).
PCBs were found in 9 of 38 samples. The highest PCB concentrations were typically
found at depths less than 3 m (10 ft). The maximum PCB concentration was
16 mg/kg, at location NPT-1.
No sampling was conducted during the RI within the North Process Pond Scraping
Disposal Area. Because the scraping disposal area received sludge from the North
Process Pond, contamination is expected to be similar in nature to the North Process
Pond.
24
-------
Burial Ground No. 4
G4TP-1
ERA Spoils Area
5 VPTjIgJ
©
•
Burial Ground No. 5 \
I618-5BG5TP-1 \
Process
Trenches
(316-5)
316-2NPT-2
51316-2 NPT-3V
North Process Pond
316-2399-1-22
North Process Pond
Scraping Disposal Area
o
o^
cr
P"
^S.
^
LEGEND
® Boreholes
|S Testpits
A Soil sample prior to Process Trench ERA
O Soil sample taken after Process Trench ERA
Source: Modified from DOE-RL 1993a.
200 METERS
F3
600 FEET
E9604048.1
Figure 5. Sampling Locations in the Northern Portion of 300-FF-l.
25
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Process Trenches. The east and west Process Trenches were sampled prior to and
following the ERA. Figure 6 shows the distribution of contaminants in the Process
Trenches both before and after the ERA. Pre-ERA sample results are considered
representative for the Process Trench Spoils Area, which is located at the north end of
the trenches.
The greatest pre-ERA concentrations of uranium-238 (to a maximum of 9,100 pCi/g)
were located near the surface at the east trench weir box. Pre-ERA concentrations of
uranium-238 were highest near the south end of the trenches, and decreased markedly
with distance toward the north end of the trenches. After the ERA, the highest
uranium-238 concentration detected (44 pCi/g) was in the west trench at both the
surface and at a depth of 1.4 m (4.5 ft), 20 m (65 ft) from the south end of the trench.
The post-ERA isotopic uranium data were rejected during data validation because the
laboratory did not provide documentation that the instrument calibration sources were
traceable to the National Institute of Standards and Testing, as required by the
validation procedure. However, the data were retained for limited use.
Thorium-228 concentrations in pre-ERA soils in both the east and west trenches ranged
from 0.52 pCi/g to a maximum of 17 pCi/g. The maximum was detected at a depth of
0.15 m (0.5 ft) in the east trenph. Post-ERA concentrations ranged from below the
detection limit at a depth of 3.3 m (11 ft) in VPT-1 to a maximum of 0.83 pCi/g at the
2-m (6.5-ft) interval in the same test pit, within the range of the apparent site
background.
Figure 6 presents pre- and post-ERA sampling data for chromium and copper. The
concentrations of these constituents generally decrease with depth. The greatest
pre-ERA copper concentrations (3,600 mg/kg) were present in the first 0.15 m (0.5 ft)
below ground surface in the east trench. Pre-ERA maximum copper concentrations
(1,500 mg/kg) in the west trench were somewhat lower, but within the same
magnitude. Pre-ERA east trench chromium concentrations vary significantly between
sampling locations, with the highest concentrations (around 180 mg/kg) in surface soils
20 m (65 ft) from the south end of the trench. Similar surface concentrations were
found 100 m (328 ft) from the south end of the trench. No post-ERA soil sample had a
chromium concentration in excess of the operable unit background UTL of 19 mg/kg.
PCBs were found in several pre-ERA surface samples in the east trench at
concentrations up to 20 mg/kg. They were tentatively identified in pre-ERA west
trench surface soils at concentrations ranging from 0.12 to 13 mg/kg. No PCBs were
detected in any post-ERA east trench samples and PCBs were only tentatively identified
in the west trench at a maximum concentration of 0.031 mg/kg.
The pre-RI data show samples with elevated concentrations of arsenic, cadmium,
thallium, and benzo(a)pyrene. The maximum values found were 319 mg/kg of arsenic,
222 mg/kg of cadmium, 25,000 mg/kg of thallium, and 27 mg/kg of benzo(a)pyrene.
26
-------
c;
Sample
No.
B01022
B01020
B01019
B01016
B014Q2
B01018
B014Q3
B014Q4
B014Q5
B014Q6
B014Q7
B014Q8
Post
ERA
Depth
(ft)
+4
+4
+1
0
0
-1
-1.5
-6
-11
-11
-11
-16
U-23J
(pCi/g)
11 OCR
1800R
93R
44R
44 R
15R
32R
12R
11R
NA
NA
19R
Co-60
(pCi/g)
1.8
1.6
0.65
0.14
ND
ND
ND
ND
ND
NA
NA
ND
Cr
(mg/kg
52
55
21
6.2
8.6
5.8
7.2
7.0
4.1
2.2
3.6
5.4
Cu
(mg/kg)
1400
1500
320
53
60
29
54
26
38
29
31
69
Pre/
Post
ERA
*
*
*
!
!
*>
!
!
j
!
i
i
^
^
^
f '
t
f>
>
\
LEGEND \
*$C Pre-ERA soil sample \
Q Post-ERA soil sample \
Approximate ERA excavation depth
(current ground level)
NA Not Analyzed
ND Not Detected
R Rejected Data (Invalidated
during data validation)
NOTE: The Process Trench ERA removed the upper four feet
of soil. The excavated soils were transported and disposed of
at the north end of the west trench.
Source: Compiled from R.I. Data (DOE-RL 1993a).
Sample
No.
B01046
B01045
B01027
B01044
Post
ERA
Depth
(ft)
+4
+ 1
0
-1
Sample
No.
B01043
B01042
B01025
B01041
Post
ERA
Depth
(ft)
+4
+1
0
-1
U-23E
(pCi/g
69R
4.3R
4.7R
30R
U-238
(pCi/g)
77R
33R
5.4R
8.6R
Co-60
(pCi/g)
1.0
0.05
0.32
0.03
Cr
(mg/kg
33
ND
ND
27
Cu
(mg/kg]
450
30
75
280
Pre/
Post
ERA
*
*
i
*
Co-60
(pCi/g)
0.14
0.07
0.05
0.08
Cr
(mg/kg
170
9.4
ND
ND
Cu
(mg/kg]
970
210
110
73
Pre/
Post
ERA
*
*
!
*
Sample
No.
B01038
B01037
B01040
B01036
B01029
B01035
Post
ERA
Depth
(ft)
+4
+4
+4
+ 1
0
-1
U-238
(pCi/g)
9100
64R
9100R
1100R
6.0R
50R
Co-60
(PCi/g)
0.79
NA
0.96
0.36
ND
0.08
Cr
(mg/kg;
180
80
130
74
ND
ND
Cu
(mg/kg)
3300
1300
3600
1200
19
140
Pre/
Post
ERA
*
*
*
*
j
*
Sample
No.
B01034
B01033
B01031
B01032
Post
ERA
Depth
(ft)
+4
+ 1
0
-1
U-238
(pCi/g)
2900R
360R
2.5R
9.2R
Co-
60
(pCi/g)
0.55
0.11
0.04
0.22
Cr
(mg/kg;
35
ND
ND
ND
Cu
(mg/kg)
1500
150
16
81
Pre/
Post
ERA
*
*
!
*
I
0 100 METERS
0 300 FEET
E9604048.4
Figure 6. Process Trench Soil Concentrations.
27
-------
Chrysene was identified in pre-ERA samples at concentrations up to 43 mg/kg. All of
the soil which these samples were taken from were moved during the ERA and are part
of the Process Trench Spoils Area.
Separate, independent TCLP tests were performed on 300 Area Process Trench soils
per EPA protocols during the RI. All of the samples passed the TCLP test criteria.
Similarly, EP Toxic Procedure tests were performed before the RI on process trench
soils with similar results.
Sanitary Sewer Trenches. Three surface soil samples were obtained from three
locations in the North Sanitary Trench during the RI. The samples were analyzed for a
comprehensive list of inorganic and organic nonradioactive constituents. However, no
radiological analyses were conducted. Sampling locations are shown in Figure 4.
Sampling was not performed in the south sanitary trench, at either of the two septic
tanks located at the west end of the trenches, or at the adjacent sludge pond. Levels of
contamination at these locations are expected to be similar to the North Sanitary
Trench.
No contaminants of concern were identified during the 300-FF-l RI. The maximum
copper concentration found during the RI was 880 mg/kg. The maximum chromium
concentration was 120 mg/kg.
Ash Pits. Three surface soil samples were obtained from the ash pits during the RI.
Samples were analyzed for metals and semivolatile organics only; radionuclide analysis
was not conducted. No contaminants of concern were identified at the surface for this
waste unit. Contaminated soil may be present beneath ash deposits in the pits, since
this area was once part of the South Process Pond.
Filter Backwash Pond. Six surface soil samples were obtained from the filter
backwash pond during the RI. Samples were analyzed for metals and semivolatile
organics only; radionuclide analyses were not conducted. No contaminants of concern
were identified for this waste unit. Contaminated soil may be present beneath ash
deposits, since this area was once part of the South Process Pond.
Retired Filter Backwash Pond. When the South Process Pond was retired in 1975,
the east basin was used for disposal of water treatment plant filter backwash. No
sampling activities were conducted during the RI. Contaminants of concern for the
soils beneath the pond are anticipated to be the same as those identified for the South
Process Pond and to require similar remedial action.
Landfills la, Ib, Ic, and Id. Surface radiation levels above background have been
found at Landfills la, Ib, Ic, and Id. Geophysical surveys were also performed for
these landfills, with the following results.
• Landfill la is a small group of waste disposal trenches.
28
-------
• Two shallow deposits and a large number of discrete objects were identified at
Landfill Ib. However, the survey did not suggest significant quantities of
waste.
• Waste materials were not identified at Landfill Ic; however, the surface debris
which were the source of the radioactive contamination were found and
removed.
• A large continuous area of waste was indicated at Landfill Id. The greatest
thickness was identified near the edges of the unit. Steel materials comprise a
significant portion of the waste.
Burial Ground 618-4. The RI surface radiation survey identified seven locations
above background levels: six near the entrance to the burial ground and one outside the
north fence. In addition to surface soil contamination, contaminated metal pieces were
also found during the survey. The existence of contaminated surface debris and areas
of elevated surface radiation activity indicates that the extent of contamination that may
require remediation is greater than the fenced area of the burial ground.
Tetrachloroethene, 1,2-Dichloroethene (DCE), and TCE were detected in soil gas at
eight sampling locations. Trichloroethene was identified in one soil sample at a
concentration of 0.4 mg/kg, and tetrachloroethene was tentatively identified in two
samples with a maximum concentration of 0.13 mg/kg.
Test pit excavation during the RI encountered radioactive pipe, scrap metal, barrels,
salt-bath precipitate, and other refuse. No indications of liquid waste disposal were
found. The refuse was located within sand and gravel fill. The thickness of the fill
was 5.8 m and 2.7 m (19 ft and 9 ft) at locations 618-4TP-1 and 618-4TP-2 (see
Figure 5), respectively. Undisturbed sandy gravel of the Hanford formation was
located below the fill. Ten soil samples were collected from two test pits during the
RI.
A uranium-238 concentration of 2,100 pCi/g was found at 1 m (4 ft) at location
618-4TP-1, and a concentration of 640 pCi/g was found at 2 m (6 ft) at location
618-4TP-2. Concentrations at other depths are substantially lower, (e.g., the next
highest concentration is 110 pCi/g at a depth of 3.3 m [14 ft] in 618-4TP-1).
Uranium-234 exhibits a similar distribution: 2,100 pCi/g at 1 m (4 ft) and a secondary
peak of 110 pCi/g at 4 m (14 ft). Radium-226 and thorium-228 were consistently
found in 618-4TP-1 over the entire depth sampled; however, concentrations exceeded
background only at a single location, where thorium-228 was detected at 2.3 pCi/g.
Radium-226 was found in only one sample at 618-4TP-2. Cobalt-60 was not found at
either sampling location.
The maximum copper and chromium concentrations were identified in 618-4TP-2 at
230 and 960 mg/kg, respectively. These highs were within an interval of 1 to 2 m
29
-------
(3 to 6 ft) below ground surface. Copper and chromium maximums in 618-4TP-1 were
significantly lower: 67 and 45 mg/kg, respectively. Comparison of the operable unit
background UTL for copper (44 mg/kg) indicates that the background UTL is only
exceeded in the upper 5 m (15 ft) of 618-4TP-1 and only in the upper 2 m (6 ft) of
location 618-4TP-2. PCBs were present at both sampling locations, with the maximum
concentration of 2.7 mg/kg identified at 0.6 m (2 ft) below ground surface in
618-4TP-2.
300-FF-5 Contamination, Over 400 samples were taken and analyzed for chemicals and
radionuclides during 7 rounds of groundwater sampling at 64 different wells. The wells
utilized were a combination of wells drilled for the RI and existing wells. Table 4 provides a
summary of contaminants in the groundwater and Table 5 provides a summary of contaminants
in surface water. River-bottom sediments were sampled near the springs and seeps, and no
contamination was found. A description of contamination by medium is presented below.
Groundwater. For groundwater, the identified contaminants of potential concern
were: total coliform bacteria, 1,2-DCE (total and trans), TCE, chloroform, nitrate,
^Sr, "Tc, tritium, total uranium, 234U, 235U, 238U, nickel, and copper. All of the
groundwater contaminants of potential concern were associated only with the
unconfmed aquifer. *
Groundwater contamination in the vicinity of the 300-FF-5 Operable Unit generally
consists of three main plumes (Figure 7). The primary plume, and the only one of the
three that is derived from 300 Area operations, is centered beneath the
300-FF-l Operable Unit. Contaminants associated with this plume are total coliform
bacteria, chloroform, DCE, TCE, nickel, copper, 90Sr, and uranium. Although the
distribution of each contaminant varies somewhat because of differing transport
properties and sources, maximum concentrations occur primarily in the vicinity of the
Process Trenches and the north and south process ponds.
A second plume, consisting of tritium, is present throughout the north and eastern
portions of the 300-FF-5 Operable Unit (Figure 7). This plume is derived from
operations in the 200 Area and is migrating into the 300-FF-5 Operable Unit from the
north. At the time of the Phase I RI sampling, maximum tritium concentrations
(approximately 12,000 pCi/L) occurred beneath the northern portions of the 300 Area
and declined to the south. The minimum detected concentrations (approximately
1,000 pCi/L) occurred approximately 400 m (1,300 ft) south of the 300-FF-5 Operable
Unit. This plume will be addressed in future ROD(s).
The third plume, consisting of 99Tc and nitrate, is migrating from the vicinity of the
1100-EM-l Operable Unit, which is located approximately 1.6 km (1 mi) west of the
southern portion of the 300-FF-5 Operable Unit. TCE is also present in groundwater
at the 1100-EM-l Operable Unit. This plume was addressed in a 1993 ROD, which
30
-------
Table 4. Summary of Groundwater Contaminants.
(Page 1 of3)
Constituents Detected
(Rounds 5, 6, <& 7)
Aluminum
Antimony
Arsenic
Barium
Bromide
Calcium
Chloride
Chromium
Cobalt
Copper
Fluoride
Iron
Lead
Magnesium
Manganese
Nickel
Nitrate
Potassium
Selenium
Well where
Maximum Value
Occurred
399-1-17A
399-3-12
399-1-18A
399-1-17B
399-2-1
399-1-21A
399-1-5
399-1-17A
399-3-2
399-1-17A
399-2-1
399-1-10B
399-1-14B
399-1-16B
399-1-17B
399-1-17A
399-1 -ISA
399-1-10B
399-1-17A
399-1-16A
399-1 -ISA
399-1 -ISA
399-1-12
Units
Hg/L
Hg/L
^g/L
Hg/L
Mg/L
Hg/L
J^g/L
Hg/L
Hg/L
^g/L
!^g/L
Hg/L
^g/L
^g/L
Hg/L
Hg/L
Hg/L
Hg/L
UR/L
Maximum
Concentration
Detected
66
37.7
6.2
70
100
55,500
140,000
4.5
5.8
4.5
1,200
450
4.1
13,000
170
140
23,000
6,800
3
Local
Background
Concentration
358
<16
12.9
210.4
-
70,336
51,740
2.4
<3
2.6
1,114
420.7
<5.2
12,912
199
5.3
13,420
6,443
<20
Previous
Maximuma
1780
ND
13.9
133
ND
74,400
26,700
10.2
3.2
11.6
1,300
560
5.6
14,200
224
118
15,600
6,880
14.1
Minimum
RBCM
.64
None
None
8
96
32
2,560
Minimum
ARAR
Screening
Levelc
-
.6
5
200
-
-
25,000
10
-
130
400
-
1.5
-
-
-
4,400
-
1000
-------
Table 4. Summary of Groundwater Contaminants.
(Page 2 of3)
Constituents Detected
(Rounds 5, 6, & 7)
Silver
Sodium
Sulfate
Tin
Vanadium
Zinc
Chloroform
1 ,2-Dichloroethylene (cis)
1 ,2-Dichloroethylene (total)
Dichloroethene (trans)
2,4,5-T
2,4,5-TP
2-Butanone
4,4'-DDD
Coliform Bacteria
Delta-BHC
Gamma-BHC (Lindane)
Endosuh°an sulfate ;•
Ethyl Benzene
Methylene chloride
Trichloroethene
Tetrachloroethene
Well where
Maximum Value
Occurred
399-3-10
399-1-14B
399-1-10A
399-1-11
399-1 -ISA
399-1-16A
399-1 -ISA
399-2-1
399-1-17A
399-1-16B
399-1-16B
399-1-16B
399-1-11
399-1-11
399-1-21A
399-1-17A
399-1-17A
399-1-16A
399-1-11
399-1-18A
399-1-16B
399-4-7
399-1-16B
399-1-14A
Units
Hg/L
^g/L
Hg/L
^g/L
Hg/L
Hg/L
^g/L
^g/L
^g/L
^g/L
Hg/L
^g/L
Hg/L
^g/L
cfii/lOOmL
Hg/L
^g/L
^g/L
^g/L
^g/L
^g^
^iR^L
Maximum
Concentration
Detected
3.8
53,000
51,000
53
12
22
22
130
180
150
0.38
0.36
11
0.002
1
.008
.002
0.045
.084
8
11
0.74
Local
Background
Concentration
<5
44,738
75,910
-
14.9
21
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Previous
Maximum3
10
64,300
54,000
ND
16.6
85.6
18
ND
150
130
ND
ND
ND
ND
280
ND
ND
ND
ND
ND
14
4
Minimum
RBCM
960
0.028
16
16
32
16
12.8
80
0.0341
-
.0063
0.08
160
1.09
0.157
Minimum
ARAR
Screening
Level0
-
-
'
-
-
-
10
10
7
-
5
-
.001
-
-
.02
-
-
.5
.5
.5
LK)
-------
Table 4. Summary of Groundwater Contaminants.
(Page 3 of3)
Constituents Detected
(Rounds 5, 6, & 7)
Gross Alpha
Gross Beta
Cobalt-60
Radium
Ruthenium- 106
Strontium-90
Technetium-99
Tritium
Uranium
Uranium-233/234
Uranium-234
Uranium-235
Uranium-238
Well where
Maximum Value
Occurred
399-1-16A
399-5-1
399-1-17A
399-1-17B
399-1-17A
399-1-17A
399-5-1
399-1-18A
399-2-2
399-1-7
399-1-17A
399-1-7
399-1-7
Units
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
^g/L
pCi/L
pCi/L
pCi/L
pCi/L
Maximum
Concentration
Detected
126
33
8.5
0.179 ^
55.6
1.28
74
11,300
150
45
25
7.7
33
Local
Background
Concentration
4.3
9.3
.
-
-
.
-
-
12.9
-
-
-
-
Previous
Maximum8
130
110
3.49
0.08
34.4
4.57
65
11,770
270
120
120
17
93
Minimum
RBCM
.304
0.0381
.481
3.51
Minimum
ARAR
Screening
Levelc
1.5
_
10
.5
^
3
.8
90
2000
2
-
-
-
-
aMaximum detected value from rounds 1-4.
bMinimum risk-based concentration for groundwater ingestion or inhalation of volatiles, assuming ICR=lxlO~7 and HQ=0. 1 .
cMinimum of chemical -specific ARARs. Have assumed screening level of 0. 1 of MCL
dValues presented only for those compounds which exceeded background and/or the previous maxima.
Note: An asterisk indicates exceedance of other values by the maximum concentration detected. Screening based on filtered data for metals, unfiltered data
for all other constituents.
ND - Not detected in rounds 1-4.
NR - Not reported.
RBC - Risk based concentration
U)
LO
-------
Table 5. Summary of Columbia River Contaminants.
Constituents
Detected
Aluminum
Barium
Cadmium
Calcium
Copper
Iron
Magnesium
Manganese
Sodium
Trichloroethene
Vanadium
Zinc
Technetium-99
Tritium
Uranium
Uranium-234
Uranium-235
Uranium-238
Units
Mg/L
Mg/L
Mg/L
Mg/L
Mg/L
Mg/L
Mg/L
Mg/L
Mg/L
Mg/L
Mg/L
Mg/L
pCi/L
pCi/L
Mg/L
pCi/L
pCi/L
pCi/L
Maximum
Concentration
Detected
1120*
47.4
2
21,000
7.2
1860*
4940
77.8*
2620
0.002
12.5*
75
5.4
3,100
0.501*
18
1.10
19
Background
Concentration
20-130
0-200
-------
316-5 Propess
Trenches I
316-2 North
Process Pond
Sanitary Leach
Trenches
316-1;South
Process Pond
OO-FF-5 Boundary
...N.I 4400.
LEGEND
Grid based on Lambert
Coordinate System, NAD83 (Meters)
+ Monitoring Well
SOURCE: DOE-RL1994b.
400 METERS
P
1200 FEET
E9604048.7
Figure 7. General Shape and Extent of 300 Area Groundwater Plumes
35
-------
required monitoring in wells upgradient of 300-FF-5 to verify that the plume did not
migrate into 300-FF-5. Figures 8 and 9 present groundwater gradients and flow
directions in the 300 Area at high and low river stages.
Sediment. Sediment samples were collected at four spring sites during low river stage
levels. Hanford Site-specific background concentrations in river sediments were
available and were compared to detected compounds in 300 Area sediments. No
compounds in the sediment detected above background concentrations exceeded risk-
based or regulatory screening. Therefore, there were no contaminants of potential
concern in the Columbia River sediments.
Surface Water. Surface water samples were taken in conjunction with riverbank
spring samples. Contaminants found in surface water for the 300-FF-5 Operable Unit
were: TCE, 99Tc, tritium, 234U, 235U, and 238U. Maximum values for these
contaminants are summarized in Table 5. Concentrations generally were observed to
be highest close to the riverbank and lowest away from the riverbank. The maximum
concentrations were all associated with the sample collected 1 m (3 ft) from the bank.
Concentrations generally increased toward the downstream end of the 300-FF-5
Operable Unit. The maximum river concentrations of the uranium isotopes, tritium,
TCE, and 99Tc all occurred at one sampling location, adjacent to a riverbank spring.
VI. SUMMARY OF SITE RISKS
The risk assessment consisted of contaminant identification, exposure assessment, toxicity
assessment, and characterization of human health and ecological risks. The contaminants of
concern were identified based on historical sampling data and inventories as well as from the
results of the remedial investigations. The exposure assessment identified potential exposure
pathways for current and future uses. The toxicity assessment evaluated the potential health
effects to human or ecological receptors as a result of exposure to contaminants. The risk
assessment was conducted in accordance with the Hanford Site Risk Assessment Methodology
(HSRAM). HSRAM was developed by DOE, in consultation with EPA and Ecology.
HSRAM is based on EPA!s Risk Assessment Guidance for Superfund (RAGS) and other EPA
guidance (both national and Region 10). HSRAM was developed to provide a common set of
exposure assumptions and provide direction on flexible, ambiguous, or undefined aspects of
the various guidance, while ensuring that Hanford Site risk assessments remain consistent with
current regulations and guidance. The results of the human health and ecological risks are
discussed below.
A. Human Health Risks
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).
36
-------
E9604048.5
o 1-12 Well Location and Number
• 4-7 Monitoring Network Well
A sws-1 Surface-Water Monitoring Station
Roads
Generalized Flow Direction
Source: DOE/RL, 1996a
Figure 8. Water Table Elevation Map Showing Flow Direction at High River Stage.
37
-------
E9604048.6
o 1-12 Well Location and Number
m 4-7 Monitoring Network Well
A sws-1 Surface-Water Monitoring Station
Roads
Generalized Flow Direction
Source: DOE/RL, 1996a
Figure 9. Water Table Elevation Map Showing Flow Direction at Low River Stage.
38
-------
Identification of Contaminants of Concern.
Data collected during the RI were used to identify contaminants present at 300-FF-l and
300-FF-5. The previous section of this ROD presents sampling results by media.
Contaminants of concern were identified in a step-wise process. First, sample results were
compared with background values. Next, the results were compared with risk-based screening
concentrations. The screening concentrations represent a potential cancer risk of 1 x 10~7 or a
hazard quotient of 0.1, considering all pathways in a residential exposure scenario. The results
were also compared to potential ARARs. Potential contaminants of concern are those that
exceed background and either the risk-based or ARAR screening. The potential contaminants
of concern were then evaluated in the baseline risk assessment.
Sixteen potential contaminants of concern were identified for 300-FF-l, based on reasonable
maximum exposure (RME) scenarios. Table 6 lists the concentrations of the potential
contaminants of concern in each 300-FF-l waste site. Seventeen potential contaminants of
concern were identified for 300-FF-5 and are listed in Table 7.
Toxicity Assessment.
Toxicity information for the contaminants of concern was found in EPA's Integrated Risk
Information System (IRIS) and/or EPA's Health Effects Assessment Summary Tables
(HEAST). The information is summarized below.
Cobalt-60, Uranium. 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 HEAST, and Eisenbud (1987), are used as the source of
radionuclide information including half-lives, lung class, gastro-intestinal (GI) absorption, and
slope factors.
Uranium also has non-radiological health affects that must be considered. Along with the
potential for inducing cancer due to radiation, uranium has been shown to cause adverse
effects on the kidneys in animal studies.
Arsenic has been classified as a Group A carcinogen, known to produce skin and lung cancer
from inhalation and direct contact. Arsenic is also known to cause non-carcinogenic affects
(keratosis and hyperpigmentation).
39
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Table 6. Maximum Concentrations of Potential Contaminants
of Concern at 300-FF-l Waste Sites.
Contaminant
Non-Radioactive
ammonia
arsenic
benzo(a)pyrene
cadmium
chrysene
PCBs
thallium
tetrachloroethene
trichloroethene
(TCE)
Radioactive
cesium- 137
cobalt-60
thorium-228
uranium-234
uranium-235
uranium-238
zinc-65
Process
Trenches
Pre-ERA
(mg/kg)
-
319
27
222
43
19.5
25,000
1.1
.1
(pCl/g)
2.4
1.8
16.8
9700
1600
9143
-
Process
Trenches
Post-ERA
(mg/kg)
-
1.6
-
-
-
.38
1
(pCi/g)
1.5
.32
.83
59.7
7.7
44.1
-
South
Process
Pond
(mg/kg).
90.0
23.3
-
13.2
-
14.5
-
(pci/g)
.63
81
1.2
1230
75
980
-
North
Process
Pond
(mg/kg)
55.9
4.3
-
-
-
42
-
(pCi/g)
37.5
3.5
3.2
1100
110
900
.32
Burial
Ground
618-4
(mg/kg)
-
7.6
-
-
-
2.7
-
0.3, soil gas
concentration
0.0024
fjig/cm3
0.39, soil gas
concentration
0.0052
fjig/cm3
(PCi/g)
1.6
-
2.25
2100
54.8
2100
-
- = Not a contaminant of potential concern at this waste management unit.
40
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Table 7. Concentrations of Potential Contaminants of Concern
in 300-FF-5.
Media/Parameter
Maximum
Detected
Concentration
MCL
Units
Groundwater
Chloroform
1,2-Dichloroethene (cis)
1,2-Dichloroethene (total)
Dichloroethene (trans)
Trichloroethene
Total coliform
Copper
Nickel
Nitrate
Ruthenium- 106
Strontium-90
Technetium-99
Tritium
Uranium-234
Uranium-235
Uranium-238
Total Uranium
22
130
180
150
14
280
11.6
140
23,000
55.6
4.57
74
11,800
120
17
93
270
100
70
-
100
5
-
-
-
44,000
-
8
900
20,000
-
-
-
20*
(Mg/L)
(Mg/L)
(Mg/L)
G"g/L)
C"g/L)
(c/100 ml)
(Mg/L)
0"g/L)
G"g/L)
(pCi/L)
(pCi/L)
(pCi/L)
(pCi/L)
(pCi/L)
(pCi/L)
(pCi/L)
G"g/L)
Surface Water
Tritium
Uranium-234
Uranium-235
Uranium-238
Total Uranium
3,100
18
1.10
19
.501
20,000
-
-
-
20*
(pCi/L)
(pCi/L)
(pCi/L)
(pCi/L)
G"g/L)
*The uranium MCL is a proposed value (56 FR 33050)
41
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Benzo(a)pyrene has been classified as a Group B2 carcinogen from oral exposure. Various
animal studies have shown evidence that benzo(a)pyrene causes stomach cancer.
Chrysene has been classified as a Group B2 carcinogen, based on results of animal studies.
The route of exposure is through ingestion.
Polychlorinated biphenyls. or PCBs, are classified as Group B2 carcinogens by all routes of
exposure. PCB's also have been shown to cause non-cancerous effects such as skin irritation.
Trichloroethene has been classified as a Group B2 carcinogen based on animal evidence.
Chronic exposures to TCE may produce liver and kidney damage and may affect the central
nervous system and the reproductive system. Neither IRIS nor HEAST provide an RfD for
TCE and the only slope factor is provided by HEAST.
Risk Characterization.
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 cancer risk, or 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 ICRs are assumed to be additive so that ICRs
can be summed for pathways and contaminants to provide pathway, contaminant, or subunit
ICRs.
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 in contaminant concentrations that might produce acute or subchronic effects.
The formula for estimation of the HQ is:
HQ - Daily Intake/RfD
42
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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. RfDs are route specific. Currently, all of the RfDs 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 RfDs should be used to evaluate dermal
exposures.
Human Health Baseline Risk Assessment. Human Health Baseline Risk Assessments were
performed for both 300-FF-l and 300-FF-5. They provide estimates of risks posed by the
waste sites and ground water under current and likely future use scenarios. The 300 Area is
currently, and is likely to stay, an industrial site. However, the Columbia River is adjacent to
the 300 Area and, as previously discussed, is used for recreational purposes and drinking
water. Therefore, the risk assessments were based on an industrial-use scenario of the waste
sites and groundwater, and recreational use of the river. Additionally, residential use of
Columbia River water was assessed. The results of the risk assessments are discussed below
and summarized in Table 8. Contaminants of concern are those contaminants whose potential
exposures present a carcinogenic rislc greater than 1 x 10"6 or a non-carcinogenic hazard index
greater than one. Contaminants present in concentrations exceeding cleanup standards are also
contaminants of concern. These are listed in Table 9 for 300-FF-l and in Table 10 for
300-FF-5.
Results of the baseline risk assessment show that three sites in 300-FF-l exceed the 1 x 10"4
risk level. These sites are the North and South Process Ponds and Process Trenches Spoils
A A 1
Pile. The potential increase in cancer risks for these sites are 2 x 10 , 2 x 10 , and 3 x 10 ,
respectively. The soil contaminants providing the highest contributions to the potential
increased risk are uranium and cobalt-60. While cobalt-60 contributes to short-term dose in
the South Process Pond, this radionuclide does not contribute to long-term dose because it has
a short (5.26 year) half-life and quickly decays to lower concentrations. Uranium, on the
other hand, has a very long half-life and will contribute to risk for thousands of years. The
exposure routes are direct contact with contaminated soil, external radiation, and inhalation
and ingestion of contaminated dust. These risks are outside EPA's acceptable risk range and
show that remedial actions should be taken at these sites. The hazard indices for the North
Process Pond, South Process Pond, and Process Trenches Spoils Pile are 0.2, 0.3, and 0.1,
respectively.
The 618-4 Burial Ground has a potential increased cancer risks of 1 x 10"4. Uranium
contributes the majority of this risk. Exposure routes are direct contact with contaminated
soil, external radiation, and inhalation and ingestion of contaminated dust. While the risk
estimate for the 618-4 Burial Ground is within EPA's acceptable risk range, it is at the upper
limit of that range. The 618-4 Burial Ground hazard index is 0.4, which indicates a low
likelihood of adverse noncancer human health effects.
43
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Table 8. Summary of Risk Estimates for 300-FF-l.
Waste Site
Process Trench Spoils Area
Process Trenches
South Process Pond
North Process Pond
Burial Ground 618-4
Sanitary Trenches
Filter Backwash Pond
Ash Pits
Pathway
Soil Ingestion
HQa
.03
.009
.1
.06
.05
.09
.008
.02
ICRb
2x10^
2xlO'7
2X1Q-6
3xlO'6
IxlO"5
5xlO'8
lxlO'6
2xlO'6
Dust Inhalation
HQ
.002
.001
.0004
.04
0
0
0
0
ICR
2X10-4
3xlO-7
lxlO'6
IxlO-4
IxlO-6
IxlO-8
2xlO'9
2xlO-9
l^iatilePiiialili
HQ
-
-
-
-
-
-
-
-
ICR
2xlO'8
0
0
0
IxlO-5
-
.
-
Dermal Exposure
HQ
.06
.02
.2
.1
.3
.2
.01
.01
ICR
2xlO-5
0
2xlO'6
2X10"6
4X1Q-6
SxlO'7
7xlO'7
IxlO'5
External Exposure0
HQ
-
-
-
-
-
-
-
-
ICR
3xl(T3
IxlO-4
2XKT4
5xlO'5
IxlO-4
.
.
.
Waste Site Total
HId
.1
.03
.3
.2
.4
.3
.02
.03
ICR
3xlO'3
IxlO-4
2xl04
2xl04
lxl(T*
6xlO'7
2xlO'6
IxlO'5
- =Not applicable
aTotal Hazard Quotient
bLifetime Incremental Cancer Risk
cApplies to radionuclides only
dTotaI Hazard Index
Note: These risk estimates are based on an industrial use scenario.
-------
Table 9. Maximum Concentrations and Cleanup Levels for Contaminants
of Concern in 300-FF-l.
Contaminant of
Concern
Cobalt-60
Uranium-234
Uranium-235
Uranium-238
Arsenicd
Benzo(a)pyrened
Chrysened
Polychlorinated
Biphenyls
Thalliumd
Maximum
Concentration3
Detected in Soils
81 pCi/g
9700 pCi/g
1600 pCi/g
9143 pCi/g
319mg/kge
27 mg/kge
43 mg/kge
42 mg/kge
25,000 mg/kge
Cleanup Levels
15 mrem/yrb
219 mg/kg
18 mg/kg
18 mg/kg
17 mg/kg
245 mg/kg
Source of Cleanup
Level
40 CFR 196C
MTCAf
MTCAf
MTCAf
MTCAf
MTCAf
aData presented are maximum levels. These contaminant levels are limited to only a few
areas (see Figure 10).
bAn exposure assessment model is used to convert between soil concentrations (pCi/g) and
dose levels (mrem/yr). For example, in 300-FF-l, the 15 mrem/yr dose from total uranium
(uranium-234, -235, and -238) equates to 350 pCi/g.
C40 CFR 196 is a draft regulation identified in an advance notice of proposed rulemaking at
58 FR 54474.
dContaminants found only in the 300 Area Process Trenches Spoils Pile.
^hese contaminant concentrations were found in locations that also had high total uranium
concentrations (above 350 pCi/g).
fState of Washington, Model Toxic Control Act, Method C, Industrial Cleanup Values For
Soils (MTCA Cleanup Levels and Risk Calculations, update February 26, 1996).
45
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Table 10. Maximum Concentrations and Cleanup Levels for Contaminants
of Concern in 300-FF-5.
Contaminant
1,2-Dichloroethene (cis)
Trichloroethene
Uranium
Maximum
Concentration
Detected in
Groundwater
During June
1992
180 //g/L
14 Mg/L
270 Mg/L
Maximum
Concentration
Detected in
Groundwater
During June
1994
130 Mg/L
5.4 //g/L
150Mg/L
Cleanup
Levels
70 Mg/L
5//g/L
20 Mg/L
Source of
Cleanup
Level
MCLa
MCLa
MCLb
aFor these contaminants the maximum contaminant level (MCL) value is lower than the
existing Washington State water quality criteria.
bThis is an EPA proposed MCL and is To Be Considered.
46
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The risk assessment results for 300-FF-5 show that the potential increased health risks were
from exposure to uranium and trichloroethene, both of which are known to cause cancer. The
total cancer risk calculated for these two contaminants is 6 x 10~6, which is less than 1 x 10~4.
The hazard index calculated for this site is 0.2, which is also less than 1, suggesting a low
likelihood of adverse noncancer human health effects.
Ecological Risk Assessment, Ecological Risk Assessments were also performed for
300-FF-l and 300-FF-5. The assessment showed that impacts were insignificant. For
300-FF-l, the evaluation showed that the Great Basin Pocket Mouse may potentially be
effected from exposure to onsite contamination. The increased risk would not have a
significant impact on mouse populations and is not transferred to any predator. Remedial
actions for the protection of human health will also provide protection for the Great Basin
Pocket Mouse. For the 300-FF-5 Operable Unit, individual organisms might receive small'
doses of contaminants, but there would not be a significant dose to any population, and
contaminants are not carried up into the food chain. Therefore, no ecological risks to major
species were identified.
Uncertainty Analysis
Uncertainty Associated with the Identification of Contaminants of Concern. The wealth
of data available (both historical data and data collected during the remedial investigation)
provides confidence that the contaminants of concern were identified in 300-FF-l and
300-FF-5. Also, the risk-based screening procedure was based on a residential-use exposure.
assessment and conservative risk levels (ICR = 1 x 10"7 and HQ =0.1).
Uncertainty Associated with the Exposure Assessment. The exposure assessment is based
on a large number of assumptions regarding the physical setting of the waste sites, and the
exposure conditions of the receptor population. An assumption was made that the
contaminants of concern were readily accessible for contact via ingestion, inhalation and
dermal exposure pathways. Actual site conditions, however, may substantially limit or
preclude such exposures. In most cases, the maximum concentrations detected are not
uniformly distributed in the soil and may be several feet below the surface.
Exposure parameters (i.e., body weight, averaging time, contact rate, exposure frequency, and
exposure duration) represent reasonable maximum values as defined in the HSRAM (DOE-RL
1993), but may not reflect actual exposure conditions. For example, the direct contact
pathways (external exposure and ingestion) use the assumption that a worker is present 8 hr/d,
146 d/yr for 20 years. To assume that a worker is in close proximity to any combination of
the waste management units for approximately half of a working lifetime, however, may not
be reasonable. Consequently, such exposure conditions are likely to contribute to an
overestimation of the risk.
The choice of intake parameters for all exposure pathways is governed by the land use being
evaluated. This assessment considers that the only on-site land use will be industrial. This
assumes that there will be no major changes in current land use at the operable unit. Although
47
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this seems highly probable based on current information, any land use change that would
increase exposures by workers or indicate a different on-site receptor population would result
in a need to reevaluate the risks presented here.
Absorption factors of contaminants from soil have been derived to evaluate the dermal
absorption pathway. Limited data are available on the absorption of chemicals from a soil
matrix. Therefore, the assessment of risks may be an overestimation or an underestimation of
the actual risk,
Uncertainty Associated with the Toxicity Assessment. Uncertainty is associated with the
toxicity values and toxicity information available to assess potential adverse effects. This
uncertainty in the information and the lack of specific toxicity information contribute to
uncertainty in the toxicity assessment.
A high degree of uncertainty in the information used to derive a toxicity value contributes to
less confidence in the assessment of risk associated with exposure to a substance. The RfDs
and SFs have multiple conservative calculations built into them (i.e., factors of 10 for up to
four different levels of uncertainty for RfDs, and the use of an upperbound estimate derived
from the linearized multi-stage carcinogenic model for SFs) that can contribute to
overestimation of actual risk. The extrapolation of data from high-dose animal studies to low-
dose human exposures may overestimate the risk in the human population because of metabolic
differences, repair mechanisms, or differential susceptibility.
Although there is substantial evidence to indicate that exposure to ionizing radiation causes
cancer in humans, the scenarios upon which this assumption is based are largely acute,
external exposures. Sources of uncertainty specific to radionuclide exposure include: the
extrapolation of risks observed in populations exposed to relatively high doses, delivered
acutely, to populations receiving relatively low dose chronic exposures; estimates of doses
delivered to target cells from the inhalation or ingestion of alpha-emitters (e.g., isotopes of
uranium and thorium); and statistical variation in the human exposure data. In accounting for
these and other sources of uncertainty, EPA risk factors for cancer incidence from radionuclide
exposure span an order of magnitude.
EPA slope factors developed to assess external exposures to radionuclides are likely to be
particularly conservative. External exposure slope factors are appropriate for a uniform
contaminant distribution (that is, an infinite slab source). Because of the penetrating ability of
high-energy photons, this assumption can only be satisfied if the uniform distribution of certain
radionuclides extends to nearly 2 m (6.6 ft) below ground surface, and over a distance of a
few hundred meters or more. The use of the 95 % UCL of the mean soil concentration to
represent this uniform radionuclide concentration only compounds the conservatism inherent in
the analysis of the external exposure pathway. The conservatism is expected to be worst for
high-energy photon emitters such as Cobalt-60 and Cesium-137. The fact that the external
exposure pathway is the risk driver in this risk assessment is therefore not surprising, and is
more an indication of the conservatism built into the evaluation of this pathway than the actual
risks associated with it.
48
-------
Some contaminants, such as PCBs, only have toxicity values for carcinogenic effects (i.e.,
SFs), but do not have toxicity values for noncarcinogenic effects (i.e., RfDs). Some of these
contaminants are known to produce systemic toxic effects in addition to cancer. Without an
RfD, quantitative evaluation of these other effects is often not possible. However, for all
contaminants of potential concern carried through the risk assessment, the level of confidence
is high that key critical health effects have been evaluated.
Uncertainty Associated with the Ecological Risk Assessment. The ecological risk
assessment is based only on estimates of an assumed exposure to the mean contaminant
concentration that is uniformly distributed across the waste management site. There are no
empirical data that can be used to validate the exposure estimates in this risk assessment.
Modeling from soil to potential ecological receptors required a number of assumptions
including soil-to-plant, plant-to-animal, and animal-to-animal transfer factors or coefficients.
If the review of the literature produced a range of values, the highest transfer factor was used
in an attempt to be protective of the environment. No evaluation or critical review was
conducted to determine if these transfer coefficients are relevant to conditions at the waste
management sites. The lack of species specific toxicity information and the assumptions and
uncertainties incorporated into the estimates of NOAELs is another source of uncertainty.
The assessment methodology biases the exposure and toxicity assessment to try and be
protective of the ecological resources. Given the uncertainties listed above it is expected that
the risk characterizations presented above are probably order-of-magnitude estimates.
Actual or threatened releases of hazardous substances from this site, if not addressed by
implementing the response actions selected in this Record of Decision (ROD), may present an
imminent and substantial endangerment to public health, welfare, or the environment.
VH. REMEDIAL ACTION OBJECTIVES
Remedial Action Objectives (RAOs) are site specific goals that define the extent of cleanup
necessary to achieve the specified level of remediation at the site. The RAOs include
remediation goals derived from ARARs, the points of compliance, and the restoration
timeframe for the remedial action. These goals are formulated to meet the overall goal of
CERCLA, which is to provide overall protection of human health and the environment.
Contaminants of potential concern were identified in site-affected media. The potential for
adverse effects to human health and the environment were initially identified in the RI reports,
and were further evaluated in the baseline risk assessments. Findings of these assessments are
summarized in the previous section. No unacceptable risks to ecological receptors have been
identified.
Land Use. A key component in the identification of RAOs is the determination of current and
potential future land use at the site. The current use and long range planning by the city,
county, and Hanford Site planners show the 300 Area as industrial. The Hanford Future Site
49
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Uses Working Group (the Working Group) was convened in 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 for the 300 Area
be based on continued industrial use.
Factors that were considered in conjunction with the Working Group proposals include: (1)
that contaminated sites which would exist indefinitely (beyond any reasonable time for assured
institutional control) would be cleaned up to standards for industrial 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 300 Area, a reasonable period of time was
identified by the Working Group as "as soon as possible (by 2018)".
Chemicals and Media of Concern. Risks from soil contaminants of concern were identified
at levels that exceed the EPA risk threshold and may, therefore, 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 10"6 to 1 x 10"4. 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 10"5. For
systemic toxicants or noncarcinogenic contaminants, acceptable exposure levels shall represent
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 quotient (HQ). For sites in the state of
Washington where the cumulative carcinogenic site risk to an individual based on reasonable
maximum exposure fpr both current and future land use is less than 1 x 10~5, and the
noncarcinogenic HQ is less than 1, action generally is not warranted unless there are adverse
environmental impacts or other considerations, such as exceedances of MCLs or nonzero
MCLGs. Risks associated with 300 Area contaminants are summarized in Table 8 and in
Section VI.
Remedial action is necessary at the following sites because the risk estimates are 10"4 or
greater: the South Process Pond, the North Process Pond, the North Pond Scraping Disposal
Area, the Process Trenches, the Process Trenches Spoils Area, and Burial Ground 618-4.
Remedial action is also necessary at the Ash Pits, the Retired Filter Backwash Pond, and
Landfill Ib because they are located in areas that were formerly part of the North or South
Process Ponds, and are expected to pose analogous risks. Remedial action is necessary at
Landfills la and Id because they are expected to pose risks analogous to Burial Ground 618-4.
Remedial action is warranted for the groundwater because the MCLs for uranium, TCE, and
1,2-Dichloroethene are exceeded. Remedial action is not needed at the Sanitary Sewage Waste
Sites, the Filter Backwash Pond, the 300-3 Aluminum Hydroxide Site, and Landfill Ic.
Institutional controls are necessary to ensure that unanticipated changes in land use do not
occur and that use of groundwater is restricted until cleanup standards are met.
The remedial action selected by this document has the following specific remedial action
objectives:
50
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1. Protect human and ecological receptors from exposure to contaminants in soils and debris
by exposure, inhalation, or ingestion of radionudides, metals or organics.
This RAO will be achieved through compliance with the MTCA cleanup values for organic
and inorganic chemical constituents in soil to support industrial land use (WAC 173-340-745),
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. These
values are given in Table 9.
2. Protect human and ecological receptors from exposure to contaminants in the groundwater
and control the sources of groundwater contamination in 300-FF-l to minimize future impacts
to groundwater resources.
This RAO will be achieved by attaining Maximum Contaminant Levels (MCLs) and non-zero
MCLGs promulgated under the Safe Drinking Water Act (SDWA). These values are given in
Table 10. The specific location and measurements of the compliance monitoring will be
documented in an operation and maintenance plan for 300-FF-5, which will be approved by
EPA. Also, the contaminants remaining in the soil after remediation will not result in further
degradation of groundwater quality.
«
3. Protect the Columbia River such that contaminants in the groundwater or remaining in the
soil after remediation do not result in an impact to the Columbia River that could exceed the
Washington State Surface Water Quality Standards.
The protection of the river will be achieved by preventing further degradation of groundwater
quality in the uranium plume such that receptors that may be affected at the groundwater
discharge point to the Columbia River are not subject to any additional incremental adverse
risks. The specific location and measurements of the compliance monitoring will be
documented in an operation and maintenance plan for 300-FF-5, which will be approved by
EPA.
Remediation Timeframe. Pursuant to CERCLA section 120 (e)(2) substantial onsite physical
remedial action will commence no later than 15 months after the issuance of this ROD. The
Remedial Design Report and Remedial Action Work Plan for the implementation of this ROD
shall include a comprehensive implementation schedule. Preliminary estimates for the waste
sites in 300-FF-l indicate that the sites could be cleaned up in approximately 4 to 7 years.
Modeling of the 300-FF-5 groundwater indicates that remediation time frames vary from 3 to
10 years.
51
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VIII. DESCRIPTION OF ALTERNATIVES
A. 300-FF-l Process Waste Unit Alternatives.
Alternative P-l: No Action. Evaluation of this alternative is required and serves as a
baseline for comparison to the other alternatives. Under this alternative, no action would be
taken to remove, treat, or contain contamination and no additional restrictions or institutional
controls would be established.
Alternative P-2a: Soil Cover. This alternative leaves soil contamination in place under a
new 2-ft-thick vegetated silty soil cover to prevent direct exposure and inhalation and ingestion
of contaminated soils. Soils contaminated above cleanup levels from the Process Trenches
Spoils Pile would be excavated and disposed in the Environmental Restoration Disposal
Facility (ERDF) or other RCRA Subtitle C compliant facility. Since uranium is long-lived,
institutional controls would be required to maintain the 45-acre silty soil cover indefinitely.
Other potential controls include fences, signs, and use restrictions. Groundwater monitoring
would be required to ensure that the contamination left in place does not cause degradation of
ground water quality.
Alternative P-2b: Consolidation and Soil Cover. This alternative reduces the vegetated
silty soil cover size required for the process waste sites as compared to alternative P-2a. This
is implemented by excavating soil/debris above cleanup standards from Landfill la and Ib and
the North Pond Scraping Disposal Area, and consolidating those materials into the North
Process Pond. Excavated soil from the Process Sewers, Landfill Id, and the South Process
Pond Scraping Disposal Area would be consolidated in the same manner into the South
Process Pond. Soils contaminated above cleanup levels from the Process Trenches Spoils Pile
would be excavated and disposed in ERDF or other RCRA Subtitle C compliant facility.
Since uranium is long-lived, institutional controls would be required to maintain the 14-acre
silty soil cover indefinitely. Other potential controls include fences, signs, and use restrictions.
Groundwater monitoring would be required to ensure that the contamination left in place does
not cause degradation of ground water quality.
Alternative P-3: Selective Excavation and Disposal. This alternative requires removal of
contaminated soil/debris with concentrations above cleanup standards. The individual process
waste units can be divided into three zones: areas where the data shows that the soil is above
the cleanup standard, areas where the data shows the soil is below cleanup standards, and areas
where the data is inconclusive. The locations of these three zones within the process waste
units are shown on Figure 10.
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-N-
0
E
o
O
300-FF-1
Operable Unit Boundary
Below Cleanup Standards
Data Inconclusive
Above Cleanup Standards
33
CD
250 meters
••
700 feet
Figure 10. Alternative P-3 Process Waste Unit Zones.
53
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Under this alternative, soil would be removed from the areas where it is known that the soil is
contaminated (above the cleanup standards) with little sampling and analysis except for
confirming all contaminated soil had been removed. Areas that are confirmed to be below the
cleanup standard would be left in place. The areas where the data is inconclusive would
require field analyses to determine if the soil was contaminated above the cleanup standards or
not and therefore would be removed or not. Excavated soil and debris would be disposed of at
ERDF or other regulated landfill. Present data indicate that once total uranium above the
cleanup standard is removed, the average concentrations of total uranium and cobalt-60 will be
such that the dose will not exceed 15 mrem/year. If verification sampling unexpectedly
indicates that the 15 mrem/year cleanup level is exceeded by the combination of uranium and
cobalt-60, institutional controls may be used to allow the cobalt-60 to decay. No additional
institutional controls would be required, beyond ensuring that unanticipated changes in land
use do not occur that could result in unacceptable exposures to residual contamination.
Alternative P-4: Excavation, Soil Washing, and Fines Disposal. This alternative is similar
to Alternative P-3, with the addition of soil washing to reduce the quantity of soil requiring
disposal. Data from the 300 Area show that the contaminants are concentrated in the fines (silt
and clay). The coarser soils (gravel and sand) are generally clean. Soil washing separates soil
according to particle size, and therefore the soil with the concentrated contaminants could be
separated from the clean soil. The concentrated soil would be disposed of in ERDF or other
regulated landfill, and the soils within cleanup standards would be replaced. Verification
sampling would also be required. No additional institutional controls would be required,
beyond ensuring that unanticipated changes in land use do not occur that could result in
unacceptable exposures to residual contamination.
B. 300-FF-l Burial Ground Alternatives.
Alternative B-l: No Action. Evaluation of this alternative is required and serves as a
baseline for comparison to the other alternatives. Under this alternative, no action would be
taken to remove, treat, or contain contamination and no additional restrictions or institutional
controls would be established.
Alternative B-2: Institutional Controls. This alternative requires setting up and maintaining
institutional controls above those currently in place. Institutional controls may include: use
and/or access restrictions and maintenance of the existing fences, signs, and existing soil
covers. Groundwater monitoring would also be required to verify the effectiveness of the
existing soil cover. These controls and the soil cover would need to be maintained long
enough for uranium to decay (millions of years).
Alternative B-3: Excavation and Removal of Burial Ground 618-4. The 618-4 Burial
Ground would be remediated through excavation and disposal of materials greater than cleanup
levels. Contaminated soil and debris would be disposed of in ERDF or other regulated
landfill. 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. Verification sampling would also be required. No additional
54
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institutional controls or post-cleanup monitoring are required, beyond ensuring that
unanticipated changes in land use do not occur that could result in unacceptable exposures to
residual contamination.
C. 300-FF-5 Groundwater Alternatives.
Alternative GW-1: No Action. Evaluation of this alternative is required and serves as a
baseline for comparison to the other alternatives. Under this alternative, no action would be
taken to remove, treat, or contain contamination and no additional restrictions or institutional
controls would be established.
Alternative GW-2: Institutional Controls. For this alternative, current institutional controls
would be continued, and restrictions on groundwater withdrawal and use would be put in
place. It is expected that the uranium concentrations in groundwater will decrease to less than
remediation goals in approximately 3 to 10 years. Trichloroethene and dichloroethene may
remain in a very small region of the water table aquifer at concentrations around the MCL.
Because of attenuation, trichloroethene and dichloroethene would not reach the Columbia
River in concentrations exceeding the MCLs or surface water quality standards. Monitoring
would continue until remediation goals are met.
i
Alternative GW-3: Selective Hydraulic Containment, This alternative combines extraction
and treatment of a localized portion of the groundwater containing the highest levels of
contamination with natural attenuation of the remainder of the aquifer. The localized portion
of the groundwater contamination plume is shown as the higher concentration, selective
remediation area in Figure 11. Groundwater would be extracted through existing and
additional groundwater wells at approximately 1,135 L/min (300 gal/min). Captured water
would be treated using a sand filter and an ion-exchange unit. The treated water would then
be discharged to the river. All treated water would meet National Pollution Discharge
Elimination System discharge standards and any other discharge standards.
Spent ion-exchange resins would be removed from the columns, drained, and appropriately
packaged for disposal. Disposal of the spent resins would be in ERDF.
Alternative GW-4: Extensive Hydraulic Containment. This alternative is similar to
Alternative GW-3 except that the entire contamination plume (see Figure 11) greater than
MCLs would be extracted and treated. Groundwater would be extracted through groundwater
wells at approximately 14,760 L/min (3,900 gal/min). Additional wells and a larger treatment
unit would be required to handle the volume of water from this option.
The extracted water would be treated and discharged in the same type of system described in
Alternative GW-3; however, additional wells would be required to extend the remediation
area. Additional wells increase the potential to disturb Native American artifacts.
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C/)
c
0)
Q)
CO
300-FF-1 Boundary
i— ~~~
399-1-16B
-N-
250 meters
iF1
700 feet
Higher Concentration Selective Remediation Area
Lower Concentration Extensive Remediation Area
Figure 11. Map of Differing Groundwater Remediation Areas.
56
E9510037.4
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Alternative GW-5: Selective Slurry Wall Containment. This alternative combines
containment of the highest levels of contamination (to prevent discharge to the Columbia
River) with natural attenuation of the remainder of the aquifer. The portion of the aquifer that
has higher concentrations is shown in Figure 11. Contaminated groundwater would be
contained by installation of a slurry wall between the contamination plume and the river,
preventing groundwater from reaching the river. A slurry wall would be installed by
excavating a trench to a depth of approximately 36 m (120 ft) and filling the excavation with a
thick slurry. This slurry is more restrictive to groundwater flow than the natural soils and
essentially creates an "in-ground dam11 that prohibits flow of the groundwater into the river.
Groundwater would also be extracted at an estimated rate of 26 L/min (7 gal/min) to ensure
that the contaminated groundwater does not flow around the outer edges of the slurry wall.
The extracted water would be treated and discharged in the same type of system described in
Alternative GW-3.
Alternative GW-6: Extensive Slurry Wall Containment. This alternative is similar to
Alternative GW-5 except that the entire plume would be contained by the slurry wall. In this
alternative, the overall length of the slurry wall is increased so that the entire plume greater
than the MCLs (see Figure 11) would be intercepted, and groundwater extraction and
treatment rates would be increased to approximately 189 L/min (50 gal/min). The extracted
water would be treated and discharged in the same type of system described in
Alternative GW-3. As with Alternative GW-4, this alternative has more potential to disturb
Native American artifacts because of the length of the wall required to intercept the entire
plume.
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 ARARs) 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.
Overall Protection of Human Health and the Environment, The no-action alternatives
(P-l, B-l, and GW-1) do not meet the overall protection criteria. Alternatives P-2a, P-2b,
and B-2 would prevent exposure to contamination as long as the soil cover and the institutional
controls are maintained. The excavation and removal alternatives (P-3 and B-3) and the
excavation, soil wash, and disposal alternative (P-4) include disposal of contaminated material
in ERDF or other regulated landfill. These excavation alternatives minimize long-term
exposure and provide the best overall protection by moving contamination sources away from
the river and groundwater.
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For 300-FF-5, all the alternatives with the exception of the no-action alternative would provide
overall protection of human health and the environment as long as the controls remain in place
to prevent using contaminated groundwater for drinking water.
Compliance with Applicable or Relevant and Appropriate Requirements. The no-action
alternatives (P-l, B-l, and GW-1) do not meet ARARs. The 300-FF-l options that leave
contamination in place meet ARARs by constructing an appropriate cover and providing long-
term monitoring and maintenance. Excavation and disposal options (P-3, P-4, and B-3) would
meet ARARs. If soil and debris are encountered which are RCRA hazardous wastes or state
dangerous wastes and which contain contaminants above the land disposal restricted levels,
they would require treatment or a treatability variance could be sought. Groundwater is not
currently used for drinking water, and such use would be prevented until remediation goals are
achieved. All groundwater alternatives will achieve ARARs through attenuation or treatment,
Long-Term Effectiveness and Permanence. The no-action alternatives (P-l, B-l, and
GW-1) do not provide long-term effectiveness and permanence. The institutional controls and
soil cover alternatives (P-2a, P-2b, and B-2) prevent exposure to surface contamination as long
as the cover is maintained; however, the cover and institutional controls would need to be
maintained for millions of years. Long-term effectiveness and permanence are better achieved
by excavation and removal options (P-3, P-4, and B-3) that contain the potential sources of
contamination much farther from the river, in other sites designed for long-term performance.
These options ensure permanence by increased containment.
All of the groundwater alternatives except the no-action alternative provide long-term
effectiveness. Uranium groundwater concentrations should be reduced to less than the
proposed MCL limit via natural attenuation of the groundwater in 3 to 10 years. Placing a
slurry wall between the plume and the river would contain the plume but could require up to
100 years to complete remediation. The institutional controls, selective hydraulic containment,
and selective slurry wall alternatives may take longer than 3 to 10 years for concentrations of
trichloroethene and dichloroethene to achieve MCLs in a limited area of the groundwater.
Institutional controls would prevent exposure until natural attenuation has reduced contaminant
concentrations.
Reduction of Toxicity, Mobility, or Volume through Treatment. The only alternatives that
include treatment are Alternatives P-4 and GW-3 through GW-6. Alternative P-4 reduces the
volume of contaminated soil to be disposed.
The extensive hydraulic and slurry wall containment alternatives (GW-4 and GW-6) contain
and treat all groundwater, reducing mobility. The selective hydraulic containment and slurry
wall alternatives (GW-3 and GW-5) provide the next best mobility reduction by containing and
treating the most contaminated portions of the plume.
Short-Term Effectiveness. Short-term risk to cleanup workers is minimized when the amount
of time to conduct the remediation is minimized. The institutional controls and soil cover
alternatives (P-2a, P-2b, and B-2) prevent exposure from surface contamination and can be
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quickly implemented (1 to 2 years). Excavation options (P-3, P-4, and B-3) take relatively
longer (2 to 7 years) and provide greater opportunity for longer exposure to contaminated soil.
For the groundwater, institutional controls would limit exposure to contaminated groundwater
until the remedial action was complete. All of the groundwater alternatives include
institutional controls for some duration. Alternatives GW-2, GW-3, and GW-4 would reach
cleanup goals in 3 to 10 years. The slurry wall alternatives (GW-5 and GW-6) may take up to
100 years. Alternative GW-2 has the least potential for cleanup worker exposure and injury
and would have the least potential for disturbance to the habitat and possible artifacts in the
operable unit.
Implementability. All alternatives evaluated for the process waste units, burial grounds, and
groundwater can be readily implemented. The institutional control and soil cover alternatives
are implementable with existing technology and would require administrative actions such as
use restrictions. Soil washing has been tested and has shown that volumes of contaminated soil
can be reduced by over 85 %. Soil washing is a more complex operation than any of the other
process waste unit alternatives.
Institutional controls on the groundwater are readily implementable with administrative
actions. Hydraulic containment alternatives require extensive design and construction and
careful operation of the groundwater pumping system. Extensive hydraulic containment is
particularly difficult because approximately 50 wells must be installed, some in areas where
facilities exist. The slurry wall alternatives are even more difficult to implement than
hydraulic containment alternatives because of the presence of buildings and buried utilities, the
potential to disturb Native American artifacts, and the extensive excavation that must be
completed.
Cost. Cost estimates for all alternatives are given in Table 11. These preliminary cost
estimates are presented for comparison purposes only. Actual costs may vary considerably.
Alternatives P-2a, P-2b, and B-2 would require long-term (millions of years) institutional
controls and groundwater monitoring to assess that the remediation was successful. A present
worth cost may not adequately reflect the total cost of such extended monitoring.
The immediate cost of implementing institutional controls for the groundwater is very low.
Most of the cost is associated with monitoring; therefore, this alternative is only slightly more
expensive than no action. The remaining alternatives are significantly more expensive.
Pumping and treating all of the groundwater to levels less than MCLs would be expensive
(about $60 million), and could take up to 100 years to complete.
State Acceptance. The State of Washington concurs with Alternatives P-3 (Selective
Excavation and Disposal), B-3 (Excavation and Removal of Burial Ground 618-4), and GW-2
(Institutional Controls for 300-FF-5).
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
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Table 11. Remediation Alternatives Cost Estimates.
Alternatives
Capital
Cost
Annual
O&M
Years
Present
Worth*
Process Waste Sites
P-l No Action
P-2a Soil Cover
P-2b Consolidate and Soil Cover
P-3 Selective Excavation and Disposal
P-4 Excavation, Soil Washing, and Fine Disposal
0.0
8.8
9.9
24.0
39.3
0.08
0.13
0.10
0.00
0.00
30
30
30
4-7
4-7
1.6
11.2
11.8
24.0
39.3
Burial Grounds »
B-l No Action
B-2 Institutional Controls
B-3 Excavate and Removal of Burial Ground 618-4
0.0
0.6
3.3
0.08
0.08
0.00
30
30
3
1.6
2.3
3.3 .
Groundwater
GW-1 No Action
GW-2 Institutional Controls
GW-3 . Selective Hydraulic Containment
GW-4 Extensive Hydraulic Containment
GW-5 Selective Slurry Wall Containment
GW-6 Extensive Slurry Wall Containment
0.0
0.1
7.9
41.0
17.0
77.0
0.06
0.08
0.28
0.98
0.89
1.20
30
10
10
10
30
30
0.9
1.4
13.2
60.0
34.0
100.0
NOTE: Present worth of operating and monitoring costs assumes 5% interest (net of inflation); time
period varies between alternatives.
"Costs in millions of dollars, estimated for mid- 1994.
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received on the RI/FS reports and the Proposed Plan. The results of the public comments
indicate acceptance of the preferred remedial alternative, with some comments suggesting
alternatively more or less strict cleanup standards.
X. SELECTED REMEDIES
The selected remedies for 300-FF-l and 300-FF-5 include Alternative P-3 (Selective
Excavation and Disposal of contaminated soil and debris from the process waste units),
Alternative B-3 (Excavation and Removal of Burial Ground 618-4), and Alternative GW-2
(Institutional Controls for Ground water). The selected remedies are the best alternatives under
the nine criteria discussed in the previous section. When compared with other alternatives, the
selected remedies provide the best overall protection of human health and the environment at a
reasonable cost. The selected remedies facilitate the reuse of the sites for other industrial uses.
The total estimated cost of the remedies is $28,700,000.
Selective Excavation and Disposal from the Process Waste Units
Soil and debris from the process waste units contaminated with radionuclides or other
hazardous constituents above cleanup? standards (Table 9) will be removed and disposed of in
ERDF. During remediation, samples will be taken or field instrumentation will be used to
monitor progress and provide data to determine whether the waste satisfies ERDF waste
acceptance criteria and ARARs. After excavation, confirmation samples will be taken to
verify that cleanup levels have been met. If the confirmation sampling unexpectedly indicates
that the 15 mrem/year cleanup level is exceeded by the combination of uranium and cobalt-60,
institutional controls may be used to allow the cobalt-60 to decay.
Soils and debris meeting cleanup standards (Table 9) will remain within the boundaries of the
process waste units.
Excavation and Disposal from Burial Ground 618-4
Soil and debris from Burial Ground 618-4 contaminated with radionuclides or other hazardous
constituents above the values in Table 9 will be removed and disposed of in ERDF. During
remediation, samples will be taken to monitor progress and provide data to determine whether
the waste satisfies ERDF waste acceptance criteria and ARARs. After excavation,
confirmation samples will be taken to verify that cleanup levels have been met. Any material
that exceeds the disposal facility acceptance criteria would be stored within 300-FF-l in
accordance with ARARs until acceptance criteria are met by treatment or approval of a
treatability variance.
Cultural Resources Review
An additional survey will be performed in conjunction with Tribal members to evaluate all
areas potentially affected by the remedial activities for the 300-FF-l Operable Unit. This
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includes waste sites that are planned to be excavated as well as operational areas. In addition,
the statutory provisions of the Native American Graves Protection and Repatriation Act will be
followed for the treatment of inadvertent discoveries of Native American remains and cultural
objects. Specifically, if discoveries are made during ground disturbing activities, the
following must take place: activity in the area of discovery must cease immediately;
reasonable efforts must be made to protect the items discovered; notice of discovery must be
given to the Agency Head and appropriate Tribes; and a period of 30 days must be set aside
following notification for negotiations regarding the appropriate disposition of these items.
Recontouring, Backfilling, and Revegetation
After excavation, the sites will be recontoured, including backfilling as necessary. Some sites
may be revegetated to stabilize the surface and reduce erosion. Although not required to
ensure effectiveness of the remedies, some sites will be revegetated in accordance with natural
resource mitigation plans developed by DOE in consultation with other natural resource
trustees.
Groundwater Monitoring and Natural Attenuation
Continued groundwater monitoring is> necessary to verify modeled predictions of contaminant
attenuation and to evaluate the need for active remedial measures.
The monitoring system will be designed and optimized to confirm that attenuation is occurring.
The monitoring frequency will be selected to ensure that achievement of the RAOs can be
verified. The specific locations and measurements will be documented in an operation and
maintenance plan for 300-FF-5, which will be approved by EPA. If monitoring does not
confirm the predicted decrease of contaminant levels, DOE and EPA will evaluate the need to
perform additional response actions. The RI/FS predicted that the RAOs would be attained in
3 to 10 years.
Institutional Controls
Institutional controls are required to prevent human exposure to groundwater and to ensure that
unanticipated changes in land use do not occur that could result in unacceptable exposures to
residual contamination. The DOE is responsible for establishing and maintaining land use and
access restrictions until cleanup criteria are met. Institutional controls include placing written
notification of the remedial action in the facility land use master plan. The DOE will prohibit
any activities that would interfere with the remedial activity without EPA concurrence. In
addition, measures acceptable to EPA that are necessary to ensure the continuation of these
restrictions will be taken before any transfer or lease of the property. A copy of the
notification will be given to any prospective purchaser/transferee before any transfer or lease.
The DOE will provide EPA with written verification that these restrictions have been put in
place.
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Investigation-Derived Waste
Remedial investigations at 300-FF-l and 300-FF-5 generated investigation-derived waste
consisting of soils, slurries from monitoring well installation, purge water generated during
development and monitoring of the wells, protective clothing used during site work, etc. This
waste is stored in the 300 Area. Soil and debris will be disposed to ERDF, as will slurries
following dewatering, in accordance with ERDF waste acceptance criteria and ARARs.
XL STATUTORY DETERMINATIONS
Under CERCLA Section 121, selected remedies must be protective of human health and the
environment, comply with ARARs, 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. The following sections discuss how the selected remedies meet these
statutory requirements.
Protection of Human Health and ttie Environment. The selected remedies protect human
health and the environment through soil and groundwater actions by preventing exposure to
contaminants in soil and groundwater and ensuring better containment. Implementation of
these remedial actions will not pose unacceptable short-term risks toward site workers.
Removal of contaminated soil and debris will prevent exposure because the ERDF is designed
for long-term containment. There will be fewer restrictions on future land use after
completion of these actions. The groundwater controls will prevent exposure to contaminated
groundwater and natural attenuation provides groundwater cleanup in a reasonable time frame,
given the uses of the site.
Compliance with ARARs. The selected remedies will comply with the federal and state
ARARs identified below. The interim remedial action for 300-FF-5 is only part of a total
remedial action that will satisfy other ARAR requirements when completed. The ARARs for
the 300-FF-l and 300-FF-5 are the following:
Chemical-Specific ARARs
• Safe Drinking Water Act (SDWA), 40 CFR Part 141, Maximum Contaminant
Levels (MCLs) for public drinking water supplies are relevant and appropriate for
establishing cleanup goals for TCE and DCE that are protective of groundwater.
• Model Toxics Control Act Cleanup Regulations (MTCA), Chapter
173-340-745 WAC, risk-based cleanup levels are applicable for establishing cleanup
levels for soil.
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• Water Quality Standards for Waters of the State of Washington, Chapter
173-201A-040 WAC, are applicable for establishing cleanup goals for TCE and
DCE that are protective of the Columbia River.
Action-Specific ARARs
• 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 Land Disposal Restrictions (40 CFR 268) are applicable for disposal of
metals-contaminated materials that are hazardous or dangerous wastes.
Location-Specific ARARs
• Archeological and Historic Preservation Act (16 USC Section 469); applicable to
recovery and preservation of 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
applicable 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 Part 402, is applicable 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
(TBCs)
• Draft 40 CFR Part 196 (58 FR 54474). Advance Notice of Proposed Rulemaking
by EPA for cleanup of radionuclides in soils to 15 mrem/year above natural
background.
• Draft 10 CFR Part 20(59 FR 43200). Draft Proposed Rulemaking by NRC for
cleanup of radionuclides in soils to 15 mrem/year above natural background, and as
low as reasonably achievable.
• Draft 10 CFR Part 834 (58 FR 16268). Draft Proposed Rulemaking by DOE for
radiation protection of the public. Establishes a dose limit of 100 mrem/year above
natural background, and as low as reasonably achievable.
• Proposed amendment to 40 CFR Part 141 (56 FR 33050). A new MCL for
uranium proposed by EPA.
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• Environmental Restoration Disposal Facility Waste Acceptance Criteria that
delineate primary requirements including regulatory requirements, 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 do 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 remedies provide overall effectiveness proportional to their
cost. The cost of the selected alternatives for the process waste units and the burial ground are
higher than the alternatives that leave? waste in place, but are significantly more protective. In
addition, the selected alternatives facilitate future beneficial uses of the sites.
Utilization of Permanent Solutions and Alternative Treatment Technologies to the
Maximum Extent Possible. The selected remedies utilize permanent solutions. Alternative
treatment technologies are not practicable for this site.
Preference for Treatment as a Principal Element The selected remedies do not utilize
treatment because, when considered against the other balancing criteria, the benefits are
insufficient to warrant the added cost. However, if the volumes of contaminated soil and
debris requiring disposal at ERDF are significantly higher than estimated, treatment (such as
soil washing for volume-reduction) could become cost-effective and could be considered.
On-Site Determination CERCLA Section 104(d)(4) states that 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 public health and welfare or the environment, the President may, at
his discretion, treat these facilities as one for the purposes of that section. The preamble to the
NCP indicates 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 waste transfer between such non-contiguous facilities without
having to obtain a permit. The 300-FF-l and 300-FF-5 Operable Units and the ERDF are all
contained within the Hanford Site, and are subject to the Tri-Party Agreement. They are
reasonably related based on geography and on the basis of the threat or potential threat to
public health, welfare, or the environment, and therefore are being treated as a single site for
response purposes under this ROD. This is consistent with the determination made in the
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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."
XII. DOCUMENTATION OF SIGNIFICANT CHANGES
DOE, EPA, and Ecology reviewed all comments submitted during the public comment period.
Upon review, no significant changes to the preferred alternatives, as originally identified in the
Proposed Plan, were necessary.
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APPENDIX A
RESPONSIVENESS SUMMARY
GENERAL
Comments were received from 9 groups and individuals, including the Hanford Advisory
Board, the Nez Perce Tribe, Heart of America Northwest, the Washington State Department
of Health, and the Washington State Department of Fish and Wildlife. All of the comments
received were generally supportive of cleanup actions in 300-FF-l and 300-FF-5. However,
some of the comments suggested stricter cleanup standards (i.e., lower concentrations) and
some comments recommended cleanup alternatives other than the preferred alternative
identified in the proposed plan.
The Hanford Advisory Board (the Board) found that the preferred alternative for 300-FF-5 was
acceptable and consistent with previous recommendations. The Board did not comment on the
preferred alternative for 300-FF-l. f
The comments (Heart of America Northwest and the Nez Perce Tribe) which suggested stricter
cleanup standards can also be considered comments on the future use of the 300 Area. All
available information, including The Future For Hanford: Uses and Cleanup, The Final
Report of the Hanford Future Site Uses Working Group, indicates the likely and expected
future use of the 300 Area is industrial. All of the waste sites in 300-FF-l are located within
the boundaries of the 300 Area. The remedial action objectives were developed to be
protective within the assumed industrial use.
The comments (the Nez Perce Tribe and a technology vendor) which recommended other
cleanup alternatives were specifically directed at 300-FF-5. The preferred (and selected)
alternative for 300-FF-5 is institutional controls with continued groundwater monitoring while
the contamination continues to decrease and dissipate over time. Modeling indicates that
concentrations of the contaminants of concern will be below standards in 3 to 10 years. In
addition, contaminated groundwater entering the Columbia River will not pose any threat to
human health and the environment during this time. The other alternatives recommended by
some comments had active treatment and/or containment components. For the reasons
described in the proposed plan and this record of decision, these alternatives were not selected.
SPECIFIC COMMENTS AND RESPONSES
Leachate tests were performed on 300 Area soil samples to determine the amount of toxic
hexavalent chromium present in the soils. Results showed only a small percentage of
teachable (hexavalent) chromium in the soil. This is surprising due to the volume of
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hexavalent chromium that has already passed through Hanford soils in the 100 and
300 Areas. What chemistry was employed in determining hexavalent chromium
concentration following leaching? We are hesitant not to consider hexavalent chromium
a contaminant of concern in the 300 Area and request a discussion concerning the
reasoning behind its exclusion.
There is a reasonable amount of corroborating physical data (leach test results and
groundwater chromium concentrations), which support the conclusion that only a small
percentage of leachable chromium exists in the 300-FF-l soils. Even though these results
may seem surprising, the physical data are conclusive and are discussed below. In addition
to the physical evidence, an analysis of the expected fate of chromium—given 300-FF-l
soil physical and chemical properties—was performed and is provided on pages 2-43 and 2-
44 in the 300-FF-l Phase III FS report. This analysis provides a reasonable understanding
of (1) why it is expected that hexavalent chromium is likely to change state to the less
toxic trivalent form in 300-FF-l soils, (2) why the trivalent chromium is likely to be
insoluble, and (3) should any remaining hexavalent chromium exist, why it is also likely to
be insoluble. This evaluation provides plausible explanations of the existing site
conditions. This analysis, coupled with the strong physical evidence, strongly suggests that
hexavalent chromium should not be a contaminant of concern for 300-FF-l.
*
The specific leach tests referenced in the comment were performed on "fines" sludge cake
soils processed from the 300-FF-l soil-washing treatability tests. The report containing
these results is available in the 300-FF-l Administrative Record and is titled, "Leaching
Tendencies of Uranium and Regulated Trace Metals from the Hanford Site 300 Area North
Process Pond Sediments," PNL-10109, dated September 1994. The treatability test
procedure concentrates contaminants into the soil fines. The leach tests were conducted to
determine the leaching tendencies of uranium and other regulated trace metals, including
chromium in concentrated fines that may be disposed to ERDF if the soil-washing
alternative is selected. Five different test methods were performed: (1) the standard
Toxicity Characteristic Leach Procedure (TCLP), (2) EPA Method 1312 Synthetic
Precipitation Leaching Procedure, (3) ASTM draft Sequential Batch Extraction of Waste
with Acidic Extraction Fluid, (4) a 1:1 batch extract test, and (5) a flow-through column
leach test. The leachate tests were analyzed using an ICP-MS. The test results are
generally conservative given the concentrated media tested and, even so, indicate a very
small percentage of leachable chromium.
Separate independent TCLP tests were performed on 300 Area Process Trench soils per
EPA protocols during the remedial investigation (RI). All the samples passed the TCLP
test criteria. Similarly, EP Toxic Procedure tests were performed before the Rl/feasibility
study (FS) on process trench soils with similar results.
Additional physical evidence includes the groundwater data. Chromium concentrations in
the groundwater are below the MCL and the freshwater aquatic life standard. An
evaluation was performed on filtered versus unfiltered groundwater samples. Virtually all
the chromium detected was associated with particles in the unfiltered samples. This
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physical data further substantiates that the remaining chromium in 300-FF-l soils is
insoluble.
Cultural resources surveys concluded no sites to be remediated contain prehistoric
artifacts because the 300 area was previously disturbed during construction. Please
provide reference to this specific site survey. We may, when needed, be available to
review cultural situations or data encountered during remedial work at the site in
accordance with the Native American Graves Protection and Reparation Act and the
Hanford Cultural Resources Management Plan.
A Cultural Resource Survey was performed for the 300-FF-l Operable Unit at the
beginning of the remedial investigation. The survey was performed by the Hanford
Cultural Resource Laboratory and given the designation HCRC # 90-300-12.
In that the Cultural Resource Survey cited above was limited in scope, an additional survey
will be performed in conjunction with tribal members to evaluate all areas potentially
affected by the remedial activities for the 300-FF-l Operable Unit. This includes waste
sites that are planned to be excavated as well as operational areas. In addition, the
statutory provisions of the Native American Graves Protection and Repatriation Act will be
followed for the treatment of inadvertent discoveries of Native American remains and
cultural objects. Specifically, if discoveries are made during ground disturbing activities,
the following must take place: activity in the area of discovery must cease immediately;.
reasonable efforts must be made to protect the items discovered; notice of discovery must
be given to the Agency Head and appropriate Tribes; and a period of 30 days must be set
aside following notification for negotiations regarding the appropriate disposition of these
items.
The proposed plan states dichloroethene, trichloroethene, and uranium were found to be
above cleanup levels in monitoring well 399-1-16B. Table 2 on page 8, indicates
concentrations of these constituents appear to be dropping. Reductions in contaminant
levels do not, however, appear to be a trend for the 300 area, as indicated in the
document entitled, Hanford Site Ground-Water Monitoring for 1994 (PNL-10698,
UC-402,403), pages 5.76 to 5.83, Higher levels of contamination in the above mentioned
constituents may actually be moving into the 300 area. We are concerned that very little
research has been completed regarding effects of dichloroethene, trichloroethene, and
uranium on salmon and salmon alluvin. We ask that these problems encourage further
research on the effects of these contaminants on salmon and other species.
Paragraph 4 mentions the contaminated monitoring well, 399-1-16B, and the Figure on
Page 7. The information would be better presented if the other area monitoring wells
were shown on the Figure, as well. Maps in the groundwater monitoring document listed
above show numerous other wells in the area; we would have no way of knowing that
from reviewing the Document.
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The trend data presented in Table 2 of the proposed plan is representative for 300-FF-5.
The data referenced in Hanford Site Groundwater Monitoring for 1994 refers to data both
in and beyond the 300-FF-5 boundary and scope. The 300-FF-5 Operable Unit is a
groundwater operable unit that underlies and is down gradient of other operable units or
waste sites. For instance, trichloroethene, technetium-99, and nitrate emanate near the
Horn Rapids landfill and are addressed in the 1100 Area Record of Decision. A tritium
plume is believed to originate from the 200-PO-2 Operable Unit and is currently migrating
south and east from the 200 East Area. Contaminants in 300-FF-5 groundwater that are
currently below MCLs, and are from a source other than the 300 Area source operable
units, will be addressed in their respective units. Also, the referenced pages in the PNL
document do not indicate that either dichloroethene or uranium is trending .upward either
within, or outside of, the 300-FF-5 boundary.
Research cited in the 300-FF-5 RI/FS has shown that the river adjacent to 300-FF-5 is not
used as a salmon-spawning area. Sampling of the river water, as part of the 300-FF-5 RI,
has shown no detection of dichloroethene, a couple of detections of trichloroethene well
below the MCL and aquatic wildlife criteria, and uranium values well below the proposed
MCL, except during extreme low river stage near the river bank. Further research on
impacts to salmon and salmon aleVin from 300-FF-5 contaminants is not required, based
on the current data.
The proposed plan is meant to be a summary-level document. Figure 3 on page 7 was
designed to depict cleanup boundary areas for selective versus extensive slurry wall and
hydraulic containment options. It is understood that a technical reviewer would want to
see more detailed information. This information is available in the Remedial
Investigation/Feasibility Study Report for the 300-FF-5 Operable Unit, DOE/RL-94-85,
issued in May 1995.
The proposed plan states, for 300-FF-5, "individual organisms might receive small doses
of contaminants, but there would not be a significant dose to any population". Since
research on the effects of dichloroethene, trichloroethene, and uranium are lacking, we
cannot fully agree with this statement.
The 300-FF-5 contaminants in the Columbia River are below surface water quality
standards and below the MCLs, except for uranium under extreme low river stages. Nine
river water samples were collected during the remedial investigation. No dichloroethene
was detected in any samples. Trichloroethene was undetected in six of the nine samples.
In the remaining three samples, trichloroethene was qualified as estimated at concentrations
of 1, 1, and 2 //g/1 which were all less than half the 5 //g/1 MCL and much less than the
21,900 //g/1 criterion for protection of aquatic life.
Exposure end-point concentrations for aquatic organisms should be those of the Columbia
River where the aquatic organisms live. The concentrations of 300-FF-5 Operable Unit
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contaminants (including uranium) measured in the Columbia River are undetectable to very
low. However, a conservative assumption was made in the ecological risk assessment
which provides a safety factor for aquatic organisms. The ecological risk assessment used
maximum groundwater concentrations as the source term to represent exposure-point
concentrations for aquatic organisms in the river. The ecological risk assessment has
shown that the small doses individual organisms might receive pose no unacceptable risk.
The Department has technical concerns regarding the document's external exposure
dosimetry estimates, particularly as they pertain to 60Co. The dosimetry estimates
contained in the technical support documents show that the cobalt concentrations that
were used as input to these calculations were an average over a very large area
(approximately 40,000 m2). The document's use of the entire South Process Pond site for
this averaging greatly underestimates the potential doses to workers and is the primary
reason that the document can erroneously claim that "this level of cobalt-60 will decay
naturally to a level of insignificant dose contribution by the time the operable unit is
completed."
The comment misunderstands how the "average" was predicted and used. The 60 pCi/g
referred to in the comment is not* an average, but an actual concentration. The sample was
taken from an area which is also highly contaminated with uranium and would be removed
under the selected alternative. The average that was used to make the dosimetry estimates
referred to in the comment, was the highest remaining 60Co level AFTER cleanup. From
the data, the highest remaining ^Co level after cleanup is 8 pCi/g. If this number is used
as an average over the entire pond, then the resulting exposure would be 1.17 mrem/yr by
the time the operable unit is completed.
The choice of an appropriate area over which to average concentrations depends upon
two factors. These are the typical area over which the reasonably maximally exposed
work would range at the site and the area of contamination which would contribute most
of an external dose. For the former, the maximum appropriate area is the size of a
facility built on the site. For the latter, the dose an individual would receive from a
uniform concentration of gamma-emitters in soil is dominated by the contribution from
soils within 30 meters of the individual, while doses from soils further away is almost
negligible. This effect is shown, for example, in Figure 6.2 of the Nuclear Regulatory
Commission's "Residual Radioactivity Contamination From Decommissioning"
(NUREG/CR 5512). The implication of this effect is that for the purposes of external
exposure dosimetry, one should not average concentrations over areas larger than
approximately 1,000 m2. Most state and federal radiological cleanups use an area of
100 m2 for such averaging unless site-specific conditions, such as an industrial scenario,
justify a larger area. This is documented in the Nuclear Regulatory Commission's
NUREG/CR 5849. If one applies this protocol to the data in Figure 2 of the Sample
Activity Report for Cobalt, one finds that the highest average concentrations are
approximately 60 pCi/g. This concentration will not be negligible in comparison to
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15 mrem/yr by the year 2018. Even if one allows for an averaging area of 1,000 m2, the
resulting maximum concentrations will not be negligible by 2018. Thus, the Department
does not believe that a soil cleanup standard, based solely upon doses from uranium, is
technically defensible without a careful assessment of the concentrations.
The scenario applied in the 300-FF-l Phase III Feasibility Study is an industrial scenario.
The levels depicted in the above paragraph (i.e., 60 pCi/g) are levels that will not exist
after the cleanup, and do not depict the levels of contamination that will exist in the year
2018. Based on Figure 2 of BHI-00618, the peak, or high, 60Co levels remaining after
cleanup would be 16 pCi/g; assuming the industrial worker modeled above spent 10% of
his outdoor time in these higher levels, his exposure would be 0.22 mrem/yr in the year
2018. Combine this with the higher average exposure used above and the total exposure to
the worker is less than 1.5 mrem/yr in the year 2018. Actual average ^Co numbers are
much less, and the resulting exposure from 60Co would be considerably lower.
Cobalt-60 is a contributor to the total dose that is compared to the 15 mrem/yr cleanup
standard. The expectation is that upon completion of the remedial action, the remaining
60Co in the South Process Pond, combined with total uranium, produce a dose no greater
than 15 mrem/yr. If verification sampling unexpectedly indicates that the 15 mrem/yr
level is exceeded, then additional actions, including institutional controls, may be used to
allow the 60Co to decay.
Another concern of the Department arises from the Phase HI Feasibility Study's assertion
that "when uranium (350 pCi/g) is removed, all potential chemical contaminants will also
be removed..." (see page ADD-4). Despite this claim, the analysis to demonstrate such
correlations, or a correlation between uranium and 60Co, is not present in that document
or any of the documents reviewed by the Department. If verification of the cleanup will
rely on such correlations between contaminants, it is essential that these correlations be
carefully documented.
The correlation or relationship has been qualitatively demonstrated for the express purpose
of guiding the remediation. A statistical analysis is not required. Also, ^Co is specifically
identified as not always following the relationship with uranium. The final verification
does not rely on this correlation. For final verification, samples will be analyzed for all
contaminants of concern.
The Department also noticed that there seem to be quality assurance problems in the data
contained in the technical support documents. The "Process Trenches" (DOE/RL-93-73)
report, for example, shows that all of the isotopic uranium analyses, which presumably
were done by alpha spectroscopy, were rejected as unusable data (see Appendix 7D of the
report). Despite this, all of that data appears in Table 4-3 of Chapter 4, with no
acknowledgment of this quality assurance problem. How is it possible that all of the
isotopic analysis of the most important site contaminant is rejected as unusable? How is
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it possible that data that was rejected as unusable is used in the analysis of the site with
no apparent reservation?
The data were qualified as rejected due to documentation required by the validation
procedure that was missing. This was attributed to two main factors; the procedure's
overly strict requirements and the labs not being told in advance of all of the
documentation that would be required. Irrespective of being rejected, the data can be used
for certain purposes such as indicators, etc. For the purposes of the decision that we
reached (i.e., cleanup is necessary), the data are useable.
WDFW recognizes that the 300 Area is potentially slated for economic development as
mentioned in The Future for Hanford: Uses and Cleanup. Summary of the Final Report of
the Hanford Future Site Uses Working Group. If an industrial scenario is actually the
land use scenario, then little effort and money should be wasted in restoring the
remediation sites to account for natural resource value injuries. However, lost natural
resource values should be mitigated off-site through improvements/enhancements at an
area of the Hanford Site which has ecological function already.
Although the existing 300-FF-l ifesources which may be affected by the planned remedial
actions may be considered to be of low to fair quality, they are not without "ecological
function.11 Onsite mitigation may be appropriate for the 300-FF-l Operable Unit sites.
The cost to replace injured natural resources at these sites should be minimal, with a high
probability of successful restoration of existing ecological functions. If future industrial
activities re-injure or destroy the mitigated natural resources, appropriate additional
mitigation measures would be evaluated.
It appears stabilization of the sites1 surfaces would be necessary to prevent erosion. Little
if any additional fill material would be required to achieve this objective. Existing
mounds of clean dirt on site could be utilized to recontour the site. It is not necessary to
bring the sites to grade since this would require additional borrow material from another
site, thus impacting natural resources at the borrow sites and requiring additional
compensatory mitigation. Sterile non-native bunchgrasses, such as crested wheatgrass
(Agropyron cristatum) and Siberian wheatgrass (Agropyron sibericuni), which were used
on the Horn Rapids Landfill, could be used to stabilize the site.
Efforts will be taken to use fill material from existing borrow sites without impacting
valuable native habitat. Waste sites will be backfilled to approximate the surrounding area
and may not require filling to a level grade since some, such as 618-4, exist now as a
gentle swale. Bunch grasses, such as Crested wheatgrass and Siberian wheatgrass, will
likely be used to revegetate these sites. If available, use of native grass seed will also be
considered.
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WDFW has expressed its concerns about the McGee Ranch to USDOE in the past. At
this time, WDFW would prefer to see no additional impacts to the McGee Ranch since it
plays a vital role in allowing genetic exchange to occur between the Hanford Site and
Yakima Training Center flora and fauna communities. Further degradation of the
McGee Ranch will have additional natural resource value impacts which may not be
mitigable at any cost.
There are no plans to use McGee Ranch soils for remediation of these waste sites.
Given the fact that the 300-ff-l operable unit may potentially be utilized for industrial
use, the list of bullets should include efforts to replace natural resource values which have
been injured with off-site compensatory mitigation. Thus, natural resource values are
restored in another area of the Hanford Site which has ecological function.
Compensatory mitigation should include affects from this project's remediation process
which include injuries of natural resources at borrow sites, haul roads, laydown pads and
extended footprint into undisturbed habitat and the actual site itself. General Comment:
This project should account for the cost of compensatory mitigation upfront to ensure
that it is budgeted. At this time, it is not reflected in the costs of the alternatives
presented earlier in the document. Comment: Please include the cost of natural resource
mitigation actions in the list of tables presented in the front of this document.
Regarding the suggestion for off site, compensatory mitigation, although the existing
300-FF-l resources which may be affected by the planned remedial actions may be
considered to be of low to fair quality, they are not without "ecological function." Onsite
mitigation may be appropriate for the 300-FF-l Operable Unit sites. The second part of
the comment suggests that compensatory mitigation should include the effects of the
projects remediation process which include injuries of natural resources at borrow sites,
haul roads, laydown pads, etc. Consideration of onsite mitigation for these types of
remediation activities are already identified in the 300-FF-l Phase III FS (see Sections
6.2.9 and 7.2.5) and will be factored into the 300-FF-l remedial design effort. The next
part of the comment indicates the project should account for the cost of compensatory
mitigation upfront to ensure it is budgeted and that it is not reflected in the cost of
alternatives presented in the FS. In response, the scope for onsite mitigation is included in
the alternative descriptions in the FS and is included in the FS cost estimates. The
additional response cost factor for restoration/mitigation is also discussed in Appendix K,
Section K.3.6.
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