United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R07-90/043
September 1990
Superfund
Record of Decision:
Weldon Spring Quarry/
Plant/Pits (USDOE), MO
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50272-101
I REPORT DOCUMENTATION
I PAGE
1. REPORT MO.
EPA/ROD/R07-90/043
3. Recipient'* Accession No.
4. TWe and Subtitle
SUPERFUND RECORD OF DECISION
Weldon Spring Quarry/Plant/Pits (USDOE), MO
Second Remedial Action - Initial
S. Report Date-
9/28/90
7.
8. Performing Organization Rept No.
t. Performing Organization Nun* and Address
10. Protoct/Ta*k/Work Unit No.
11. ContrscU.C) or Gr*nt(G) No.
(C)
(G)
12. Sponsoring Organization Nun* and Address
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Type of Report * Period Covered
800/000
14.
IS. Supplementary Note*
16. Abstract (Limit: 200 word*)
The 226-acre Weldon Spring Quarry/Plant/Pits (USDOE) site is a former ordnance works and
chemical plant near the city of Weldon Spring in St. Charles County, Missouri. The site
is divided into two noncontiguous areas: a 217-acre chemical plant area, comprised of
various buildings, ponds and four raffinate pits, and a 9-acre quarry, which forms a
valley wall at the edge of the Missouri River floodplain. Since the early 1940s, the
;te has been used by various government agencies for chemical and ordnance processing
-th chemical and radioactive waste disposal in the quarry. From 1941 to 1946, the site
was an Army ordnance works used for the production of trinitrotoluene (TNT) and
dinitrotoluene (DNT) explosives, and the quarry was used to dispose of the chemical
wastes. From 1955 to 1966 the Atomic Energy Commission (AEC), the predecessor to the
Department of Energy, constructed and operated the chemical plant for processing uranium
and thorium. Types of wastes disposed of onsite included uranium and thorium ore
residues (drummed and uncontained), radioactively contaminated building debris,
processing equipment, and residues of TNT and DNT from cleanup of the former ordnance
works. Except for partially decontaminating buildings and dismantling some equipment,
the site has not been used since 1967. In 1990, EPA released a remedial
(See Attached Page)
17. Document Analyse a. Descriptor*
Record of Decision - Weldon Spring Quarry/Plant/Pits (USDOE), MO
Second Remedial Action
Contaminated Media: soil, sludge, debris
Key Contaminants: organics (PCBs, PAHs), metals (arsenic, lead), radioactive
materials
b. Identifiers/Open-Ended Term*
e. COSATI Held/Group
18. Availability Statement
I
It. Security CI»**(Thi* Report)
None
20. Security Cine (ThU Page)
None
21. No. of Page*
43
22. Price
(SeeAN9-Z39.18)
See Instructions on Rtvene
OPTIONAL rOHM 272 (4-77)
(Formerly NTIS-35)
Department of Commerce
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EPA/ROD/R07-90/043 ,
?ldon Spring Quarry/Plant/Pits (USDOE), MO .
cond Remedial Action . . .
Abstract (Continued)
investigation/feasibility study and proposed plan, which documented five remedial actions
for the quarry. The first remedial action involves treating contaminated surface water,
followed by discharge of treated water to the Missouri River. The second remedial
action, which is documented in this Record of Decision (ROD), addresses interim
deposition of bulk wastes in the quarry to minimize future ground water and air
contamination and to facilitate additional characterization of waste and residuals in and
around the quarry. Final decisions for disposal of wastes will be made in a subsequent
ROD for the chemical plant. Future remedial actions will address materials remaining In
the quarry walls and floor, ground water contamination, and contaminated properties
outside the quarry. The primary contaminants of concern affecting the quarry soil,
sludge, and debris are organics including PCBs and PAHs; radioactive materials; and
metals including arsenic and lead.
The selected interim remedial action for this site includes excavating an estimated
95,000 cubic yards of chemically and radioactively contaminated bulk wastes from the
quarry and temporarily storing the wastes onsite in the chemical plant area; and
implementing site access restrictions. The estimated total cost for this remedial action
is $11,000,000. There are no O&M costs associated with this remedial action.
PERFORMANCE STANDARDS OR GOALS: Not provided.
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SEP *41990
REMD SECTION
RECORD OF DECISION FOR THE MANAGEMENT OF THE
BULK WASTES AT THE WELDON SPRING QUARRY
WELDON SPRING, MISSOURI
September 1990
.-t.fi>'r-
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DECLARATION
SITE NAME AND LOCATION
Weldon Spring site
St. Charles County, Missouri
STATEMENT OF BASIS AND PURPOSE
1*.
This decision document presents the selected remedial action
for the quarry bulk waste operable unit of the Weldon Spring site
in St. Charles County, Missouri. The Weldon Spring site consists
of two distinct areas that comprise one contiguous site as listed
on the National Priorities List (NFL). This remedial action was
selected in accordance with the Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA), as amended, and
to the extent practicable, the National Oil and Hazardous
Substances Pollution Contingency Plan (NCP). This decision is
based on the administrative record file for this site.
The State of Missouri concurs with the selected remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from
this site, if not addressed by implementing the response action
selected in this record of decision, nay present an imminent and
substantial endangerment to public health and welfare, or the
environment.
DESCRIPTION OF REMEDY
This operable unit remedial action is the second of five
response actions planned as part of the overall remedial action for
the Weldon Spring quarry. The first response action to be
initiated at the quarry is a removal action involving treatment of
wtqtMrod.qrd/jtj
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contaminated surface water and discharge of the treated water to
the Missouri River. An engineering evaluation/cost analysis
(EE/CA) report has been prepared to evaluate alternatives for
management of this water. The quarry water removal action is
expected to be initiated in 1991.
The function of this operable unit is to remove bulk wastes
from the quarry. This will eliminate the wastes as a potential
continuing source of groundwater contamination and minimize risks
associated with exposure to contaminants released into the air. It
will also facilitate additional characterization of the wastes and
residual contamination in and around the quarry.
Bulk wastes are defined as materials that can be removed from
the quarry using standard equipment and procedures. This remedial
action is not the final remedial action for the quarry, and it does
not address final disposition of the bulk wastes. Disposal
decisions for these wastes will be made as part of the remedial
action decision for the chemical plant area of the Veldon Spring
site. These decisions are being addressed in a remedial
investigation and feasibility study which is currently in
preparation. A decision on the final remedial action for the
quarry will be made in a subsequent decision making process after
the bulk wastes have been removed.
The major components of the selected remedy include:
o Removal of the bulk wastes from the quarry using standard
equipment and procedures.
o Transporting the bulk wastes along a dedicated haul road
to the chemical plant area of the Weldon Spring site.
o Placing the bulk wastes in controlled storage in an
engineered temporary storage facility.
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Following removal of the wastes, detailed studies will be made
of the empty quarry and local groundwater system. These studies
will facilitate decisions with regard to the three remaining
components of the quarry remedial action, i.e., (1) residual
materials remaining in the quarry vails and fissures, (2)
groundwater, and (3) vicinity properties. The vicinity properties
are contaminated properties that are outside the quarry and for
which the U.S. Department of Energy is responsible (e.g., the Femme
Osage Slough). Comprehensive response actions for residual
materials, groundwater, and vicinity properties can be developed
only after the bulk wastes have been removed from the quarry so
that the nature and extent of residual contamination and migration
pathways can be fully assessed. These actions, which will address
final quarry cleanup criteria, will be developed in consultation
with Region VII of the U.S. Environmental Protection Agency (EPA)
and the State of Missouri and will be described in future
documents.
DECLARATION
The selected remedy is protective of human health and the
environment; it complies with Federal and State requirements that
are legally applicable or relevant and appropriate to the remedial
action, unless those requirements have been properly waived in
accordance with CERCLA; and it is cost effective. This remedy
utilizes permanent solutions and alternative treatment technologies
to the maximum extent practicable given the limited scope of this
remedial action. However, because this action constitutes neither
the final remedy for the quarry nor the final decision for
disposition of the bulk wastes, it does not satisfy the statutory
preference for treatment as a principal element of the remedy.
Potential treatment technologies will be considered in the process
for selection of the final remedy for the quarry and for final
disposition of the bulk wastes.
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Because this remedy may result in hazardous substances
remaining on site above health-based levels, a review will be
conducted within five years after commencement of this remedial
action to ensure that the remedy continues to provide adequate
protection of human health and the environment.
Regional'Administrator, U.S. Environmental
Protection Agency Region VII
Date
Oak Ridge Operations Office Manager,
U.S. Department of Energy
Date
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TABLE OF CONTENTS
SECTION PAGE
DECISION SUMMARY 1
1 SITE NAME, LOCATION, AND DESCRIPTION 1
2 SITE HISTORY. 7
3 HIGHLIGHTS OF COMMUNITY PARTICIPATION .11
4 SCOPE AND ROLE OF OPERABLE UNIT ,.. . . 13
5 SITE CHARACTERISTICS 18
5.1 Setting 18
5.2 Waste Characteristics 20
6 SUMMARY OF SITE RISKS 33
6.1 Contaminant Identification 33
6.2 Exposure Assessment 34
6.3 Potential Health Risks 37
6.4 Potential Environmental Risks 39
7 POTENTIALLY APPLICABLE OR RELEVANT AND APPROPRIATE 41
REQUIREMENTS
7.1 Federal Environmental Laws 42
7.1.1 Resource Conservation and Recovery Act 42
7.1.2 Safe Drinking Water Act 45
7.1.3 Clean Water Act 46
7.1.4 Clean Air Act 46
7.1.5 Toxic Substances Control Act 48
7.1.6 Atomic Energy Act 49
7.1.7 Uranium Mill Tailings Radiation Control Act...50
7.1.8 Other Potential Federal ARARs 51
7.2 State Environmental and Facility Siting Laws 52
7.2.1 Missouri Air Quality Standards 52
7.2.2 Missouri Air Pollution Control Regulations.... .52
7.2.3 Missouri Radiation Regulations 53
7.2.4 Missouri Hazardous Waste Management Laws 53
7.2.5 Other Potential State ARARs 54
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TABLE OF CONTENTS (continued)
SECTION PAGE
7.3 To Be Considered Requirements 54
7.3.1 DOE Order 5400.5—Radiation Protection of
the Public and the Environment 54
7.3.2 DOE Order 5480.11—Radiation Protection for
Occupational Workers 55
8 DESCRIPTION OF ALTERNATIVES 57
8.1 Alternative 1: No Action 57
8.2 Alternative 2: Surface Containment 57
8.3 Alternative 3: Surface and Subsurface Containment....58
8.4 Alternative 4: In Situ Treatment 58
8.5 Alternative 5: Expedited Excavation with Temporary
Storage at the Chemical Plant Area 59
8.6 Alternative 6: Delayed Action Pending the Record
of Decision for the Site 60
8. 7 Evaluation of Preliminary Alternatives 60
9 SUMMARY OF COMPARATIVE ANALYSIS OF FINAL ALTERNATIVES 64
9.1 Evaluation of the Final Alternatives 64
9.1.1 No Action 64
9.1.2 Expedited Excavation with Temporary Storage
at the Chemical Plant Area 65
9.1.3 Delayed Action Pending the Record of Decision
for the Site 67
9.2 Comparison to the Nine Evaluation Criteria 68
9.2.1 Threshold Criteria 68
9.2.1.1 Overall Protection of Human Health
and the Environment 68
9.2.1.2 Compliance with ARARs 68
9.3 Primary Balancing Criteria 69
9.3.1 Long-term Effectiveness and Performance 69
9.3.2 Reduction of Toxicity, Mobility, and Volume
through Treatment 69
9.3.3 Short-Term Effectiveness 70
9.3.4 Implementability 70
9.3.5 Cost 70
9.4 Modifying Criteria 71
9.4.1 State Acceptance 71
9.4.2 Community Acceptance 71
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TABLE OF CONTENTS (continued)
SECTION PAGE
10 SELECTED REMEDY 72
11 STATUTORY DETERMINATIONS 73
11.1 Protection of Human Health and the Environment 73
11.2 Compliance with Applicable or Relevant and
Appropriate Requirements 75
11.2.1 Location-Specific ARARs. V. .75
11.2.2 Action-Specific ARARs 76
11.2.3 Contaminant-Specific ARARs 80
11.3 Cost Effectiveness 82
11.4 Utilization of Permanent Solutions and Alternative
Treatment Technologies to the Maximum Extent
Practicable 82
11.5 Preference for Treatment as a Principal Element....83
RESPONSIVENESS SUMMARY 84
wtqtMTod.qrd. ji] ill
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LIST OF TABLES
TABLE PAGE
1 History of Disposal Activities at the Weldon
Spring Quarry 10
2 Concentrations of Radionuclides in the Quarry
Bulk Wastes 26
3 Concentrations of Chemicals Detected in the
Quarry Bulk Wastes in the 1984-1985
Characterization Study and Background
Concentrations in Missouri Soils .- 27
4 Concentrations of Chemicals Detected in the
Quarry Bulk Wastes in the 1986 Characterization
Study 30
5 Concentrations of Nitroaromatic Compounds in
Surface Soils at the Quarry 32
6 Carcinogenic Risks and Health Hazard Indexes
for the Passerby and Trespasser Scenarios 39
7 Radiation Protection Standards - Limiting Values
for Assessed Dose from Exposure of Occupational
Workers to Radiation 56
8 Screening of Preliminary Alternatives 62
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LIST OP FIGURES
FIGURE PAGE
1 Location of the Weldon Spring Site,
Wei don Spring Missouri 2
2 Map of the Weldon Spring Site and Vicinity 3
3 Layout of the Weldon Spring Quarry 5
4 Surface Hydrological Features in the Vicinity
of the Quarry and Location of Production
Wells in the St. Charles County Well Field 6
5 Major Environmental Compliance Activities
and Related Documents for the Weldon Spring
Site Remedial Action Project 14
6 Environmental Compliance Components for the
Weldon Spring Quarry 16
7 Uranium-238 Radioactive Decay Series 22
8 Thorium-232 Radioactive Decay Series 23
9 Surface Radioactive Contamination at the Quarry 24
10 Subsurface Radioactive Contamination at the Quarry....25
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DECISION SUMMARY
1 SITE NAME, LOCATION, AND DESCRIPTION
The Weldon Spring site is located in St. Charles County,
Missouri, near the city of Weldon Spring, about 48 km (30 mi) west
of St. Louis (Figure 1). The site consists of two noncontiguous
areas: (1) the chemical plant area and (2) the quarry. The
chemical plant area is about 3.2 km (2 mi) southwest of the
junction of Missouri (State) Route 94 and U.S. Route 40/61. The
quarry is about 6.4 km (4 mi) south-southwest of the chemical plant
area and about 8 km (5 mi) southwest of the town of Weldon Spring.
Both the chemical plant area and the quarry are accessible from
State Route 94 and are fenced and closed to the public. The
locations of the chemical plant area and the quarry are shown in
more detail in Figure 2.
The chemical plant area covers about 88 ha (217 acres) and
contains various buildings and ponds (including four raffinate
pits) as well as gravel and paved surfaces. Vegetation in this
area is predominantly grasses, shrubs, and small trees. The August
A. Busch Memorial Wildlife Area is located to the north, the Weldon
Spring Wildlife Area to the south and east, and the U.S. Army
Reserve and National Guard Training Area to the west.
The quarry was excavated into a limestone bluff that forms a
valley wall at the edge of the Missouri River alluvial floodplain.
Prior to 1942, it was mined for limestone to support various
construction activities. The quarry is about 300 m (1,000 ft)-long
by 140 m (450 ft) wide and covers an area of approximately 3.6 ha
(9 acres). The main floor comprises approximately 0.8 ha (2 acres)
and currently contains about 11,000 m3 (3,000,000 gal) of ponded
water covering about 0.2 ha (0.5 Acre). The quarry is vegetated
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T^WtoMM Spring H^gM. |V
FIGURE 1
LOCATION OF THE WELDON SPRINQ SITE, WELDON SPRING, MISSOURI
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••M^
August A. Busch
Memorial WiWIilt Area
U.S Army Rt«rv* and
\ National Guard Training Arta
W«ldon Spring
2 Kitom«l«rs
/*/
FIGURE 2
MAP OF THE WELDON SPRING SITE AND VICINITY
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with grasses, shrubs, and trees, and is surrounded by the Weldon
Spring Wildlife Area. The general layout is shown in Figure 3.
The Missouri-Kansas-Texas Railroad line formerly passed just
south of the quarry. This line was recently dismantled, and the
right-of-way has been converted to a gravel-based public trail for
hiking and biking (the Missouri River State Trail). A rail spur
enters the quarry at its lower level from the west and extends
approximately one-third of its length. The spur is overgrown with
\:
vegetation and is in a state of disrepair. The St. Charles County
well field is located to the southeast between the quarry and the
Missouri River (Figure 4). The nearest well is located about
0.8 km (0.5 mi) from the quarry.
The quarry and the chemical plant area are related as to
history and purpose, are reasonably close in proximity, and are
compatible with regard to remediation approach. Therefore, they
are considered one Comprehensive Environmental Response,
Compensation and Liability Act (CERCLA) site for purposes of this
response action.
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Inactive
Water
Treatment '/
Plant ''
50 !00 Meters
FIGURE 3
LAYOUT OF THE WELDON SPRING QUARRY
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J** — - * . .»fc
Oup* Crrtt V.
I) » QUARRY'*
// •-:•.'•>•
'•^-•"I^QBJB*5"^*
'-*F«mm« t»w
£1*91 ;
03 /
.
v
09
We!)s
O4
/
«
r
/
1000
?OOCFt«:
M
200 40C «OC
FIGURE 4
SURFACE HYDROLOGICAL FEATURES IN THE VICINITY OF THE
QUARRY AND LOCATION OF PRODUCTION WELLS IN THE
ST. CHARLES COUNTY WELL FIELD
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2 SITE HISTORY
In April 1941, the U.S. Department of the Army acquired about
7,000 ha (17,000 acres) of land in St. Charles County, Missouri,
for construction of the Weldon Spring Ordnance Works. From
November 1941 through January 1944, the Atlas Powder Company
operated the ordnance works for the Army to produce trinitrotoluene
(TNT) and dinitrotoluene (DNT) explosives. The ordnance works was
reopened during 1945 and 1946 but was closed and declared surplus
to Army needs in April 1946. By 1949, all but about 810 ha (2,000
acres) had been transferred to the State of Missouri (now the
August A. Busch Memorial Wildlife Area) and the University of
Missouri (as agricultural land). Much of the land transferred to
the University of Missouri was subsequently developed into the
Weldon Spring Wildlife Area. Except for several small parcels
transferred to St. Charles County, the remaining property became
the current chemical plant area and adjacent U.S. Army Reserve and
National Guard Training Area.
The U.S. Atomic Energy Commission (AEC), a predecessor of the
U.S. Department of Energy (DOE), acquired 83 ha (205 acres) of the
former ordnance works property from the Army by permit in May 1955,
and the property transfer was approved by Congress in August 1956.
An additional 6 ha (15 acres) was later transferred to the AEC for
expansion of waste storage capacity. The AEC constructed a feed
materials plant, now referred to as the chemical plant, on the
property for the purpose of processing uranium and thorium ore
concentrates. The quarry, which had been used by the Army since
the early 1940s for disposal of chemically contaminated materials,
was transferred to the AEC in July 1960 for use as a disposal site
for radioactively contaminated materials.
The feed materials plant wa*s operated for the AEC by the
Uranium Division of Mallinckrodt Chemical Works from 1957 to 1966.
During this period, the AEC used the quarry to dispose of uranium
wcqbwrod.qrd/j«j 7
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and thorium residues (drummed and uncontained), radioactively
contaminated building rubble and process equipment, and TNT and DNT
residues from cleanup of the former ordnance works. Following
closure by the AEC, the Army reacguired the chemical plant site in
1967 and began converting the facility for herbicide production.
The buildings were partially decontaminated, and some equipment was
dismantled. Contaminated rubble and equipment from some buildings
were placed in the quarry. In 1969, prior to becoming operational,
the herbicide project was canceled. Since that time, the plant has
remained essentially unused and in caretaker status.
In 1971, the Army returned the 21-ha (51-acre) portion of the
property containing the raffinate pits to the AEC but retained
control of the rest of the chemical plant area. As successor to
the AEC, the DOE assumed responsibility for the raffinate pits. In
1984, the Army repaired several of the buildings; decontaminated
some of the floors, walls, and ceilings; and removed some
contaminated equipment to areas outside of the buildings. In Kay
1985, the DOE designated control and decontamination of the Weldon
Spring site as a major Federal project under its Surplus Facilities
Management Program. In May 1988, the DOE redesignated the project
as a major system acquisition.
On October 1, 1985, custody of the Army portion of the
Chemical plant area was transferred to the DOE. On October 15,
1985, the U.S. Environmental Protection Agency (EPA) proposed to
include the Weldon Spring quarry on its National Priorities List
(NPL); this listing occurred on July 22, 1987. On June 24, 1988,
the EPA proposed to expand the listing to include the chemical
plant area. This proposal was finalized on March 13, 1989, and the
expanded site was placed on the NPL under the name "Weldon Spring
Quarry/Plant/Pits (USDOE/Army)." The balance of the former Weldon
Spring Ordnance Works property,/which is adjacent to the DOE
portion and for which the Army has responsibility, was included on
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the NPL as a separate listing on February 21, 1990, under the name
"Weldon Spring Former Army Ordnance Works."
A summary of disposal activities at the quarry is presented in
Table 1. Based on historical data and characterization results, an
estimated 73,000 m3 (95,000 yd3) of contaminated materials is
present in the quarry; of this, approximately 31,000 m3 (40,000 yd3)
is rubble, 39,000 m3 (51,000 yd3) is soil and clay, and 3,000 m3
(4,000 yd3) is pond sediment.
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TABLE 1 History of Disposal Activities mi the Heldon Spring Quarry
Estimated
time Period Watte Type
volume*
yd3
1942 - 1945 TNT and DNT waste
1946 TNT and DNT watte b b
1946 • 1957 TNT and DNT residues and contaminated rubble froai - - ..
cleanup of the ordnance works (in deepest part and in
northeast corner of quarry) • *"•
1959 3.81 thorium residues (drummed, currently below water 150 200
level)
1960 - 1963 ' Uranium- and radium-contaminated rubble fro* demolition 38.000 50.000
of the St. Louis Dettrehan Street feed plant (covering
0.4 ha [1 acre] to a 9-a [30-ft] depth in deepett part
of quarry)
1963 - 1966 High-thorium-content waste (in northeatt corner of 760 1,000
quarry)0
1963 - 1966 Uranium and thorium residues from the chemical plant - - - -
and off-tite facilities; building rubble and procett
equipment (both drummed and uncontained)
1966 3.OX thorium residues (drummed, placed above water 460 600
level in northeatt corner of quarry); TNT residues from
cleanup of the ordnance works (placed to cover the
drums)
1968 - 1969 Uranium- and thorium-contaminated rubble and equipment 4,600 6,000
from interiors of some chemical plant buildings (101,
103, and 105)
" A hyphen indicates that the watte volume estimate it not available.
b An estimated 90 tons of TNT/DNT waste was disposed of in 1946.
c Tris MS a prricn of tre taste o-yraUy (toned at ire Aiy armnl to ffwrite City. lUTois; ant of this
from the quarry for the purpose of recovering rare earth elements. _
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3 HIGHLIGHTS OF COMMUNITY PARTICIPATION
A remedial investigation/feasibility study (RI/FS) was
conducted in accordance with the requirements of CERCLA, as
amended, to document the proposed management of the quarry bulk
wastes as a focused interim remedial action. Documents developed
during the RI/FS included the RI report, a baseline risk evaluation
(BRE), and an FS report. The RI/FS and proposed plan were released
to the public on March 5, 1990. An informational bulletin was also
prepared to summarize this proposed action and facilitate the
community participation process.
These documents, along with other documents in the
administrative record file, have been made available to the public
in the public reading room at the Weldon Spring site. Copies of
these documents have also been provided at five additional
information repositories at the following locations: the Memorial
Arts Building at Lindenwood College (St. Charles, Missouri),
Kathryn M. Linneman Branch of the St. Charles City/County Library
(St. Charles, Missouri), Spencer Creek Branch of the St. Charles
City/County Library (St. Peters, Missouri), Kisker Road Branch of
the St. Charles City/County Library (St. Peters, Missouri), and
Francis Howell High School (St. Charles, Missouri). A notice of
availability of these documents was published in the St. Charles
Journal on March 4, 1990, and the St. Charles Section of the St.
Louis Post Dispatch on March 28, 1990.
A public comment period was held from March 5, 1990, through
April 9, 1990. A public meeting was held on March 29, 1990, at the
Ramada Inn in Went2vilie, Missouri, as a part of the public
participation process. This public meeting was advertised in the
two newspaper announcements described above. At this meeting,
representatives from the DOE, EPA Region VII, and the State of
Missouri answered questions about the «ite and the remedial
alternatives under consideration for the quarry bulk wastes.
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Transcripts of the meeting are included as part of the
administrative record file for this operable unit remedial action.
The administrative record file includes the information used to
support the selected remedy. Documents in the administrative
record include the RI, BRE, and FS reports.
In addition to the public meeting, the DOE held numerous
briefings and meetings with public officials, school
administrators, special interest groups, and members of the general
public. These meetings, which were generally informal, allowed for
an effective exchange of information and receipt of public input.
A response to the comments received during the public comment
period is included in a responsiveness summary, which was prepared
as a separate document. A summary of the major issues raised
during the public comment period is provided in this record of
decision. This decision document presents the selected remedial
action for management of the bulk wastes at the Weldon Spring
quarry in accordance with CERCLA, as amended, and to the maximum
extent practicable, the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP). The decision for this site is
based on the administrative record.
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4 SCOPE AND ROLE OF OPERABLE UNIT
The DOE is addressing the quarry bulk wastes as an operable
unit remedial action (OURA) as part of the overall remedial action
planned for the Weldon Spring site. The two general types of
remedial actions that can be addressed as OURAs are (1) final
actions that completely remediate a discrete area of a site or (2)
interim actions taken to facilitate cleanup and to mitigate an
ongoing release or threat of a release or to limit a potential
pathway of exposure. Remedial action for the quarry bulk wastes
falls into the second category. The implementation of a response
action as an OURA must be consistent with the permanent remedy for
the entire site, even though the action might be implemented prior
to selection of the final remedy.
Defining the quarry bulk wastes as an OURA of the Weldon
Spring site makes it possible to expedite management of these
wastes. This action does not address final disposal of the quarry
bulk wastes. As discussed in more detail below, that decision will
be made as part of a subsequent remedy selection process for the
chemical plant area.
Quarry bulk wastes are defined as the chemically and
radioactively contaminated solids present in the quarry that can be
removed using standard equipment and techniques. The total volume
of these wastes—which consist primarily of soils, sludges,
equipment, and structural debris—is about 73,000 m3 (95,000 yd3).
This OURA for the quarry bulk wastes is one of several
components for overall remediation of the Weldon Spring site. An
overview of the environmental strategy for achieving overall site
remediation is presented in Figure 5. Remedial action alternatives
for the chemical plant area will be evaluated in a separate RI/FS.
This RI/FS will be modified to incorporate the requirements of an
vsqbwrad.qrd/j*j 13
-------
BRA • Baseline Risk Assessment
BRE • Baseline Risk Evaluation
EE/CA • Engineering Evaluation/Cost Analysis
EIS • Environmental Impact Statement
FS • Feasibility Study
PP • Proposed Plan
Rl • Remedial Investigation
FIGURE 5
MAJOR ENVIRONMENTAL COMPLIANCE ACTIVITIES AND RELATED
DOCUMENTS FOR THE WELDON SPRING SITE REMEDIAL
ACTION PROJECT
-------
environmental impact statement (EIS) for compliance with the
National Environmental Policy Act (NEPA). This integrated process
is being referred to as an RI/FS-EIS.
As depicted in Figure 5, various interim actions (both removal
actions and operable unit remedial actions) will be performed prior
to completion of this RI/FS-EIS in order to mitigate actual or
potential releases of radioactive or chemical contaminants into the
environment. Disposal decisions will be made as part of the
remedial action decision for the chemical plant area and will be
addressed in the RI/FS-EIS that is currently in preparation.
Management of the bulk wastes is one of five separate
components of the overall environmental response under
consideration for the quarry (Figure 6). The five components are
(1) surface water, which provides the hydraulic gradient for
contaminant migration to groundwater; (2) bulk wastes, which
constitute the source of contaminants migrating into the air and
underlying groundwater at the quarry; (3) materials remaining in
the quarry walls and floor after bulk waste removal (i.e.,
residuals); (4) groundwater; and (5) vicinity properties, which are
contaminated properties outside the quarry for which the DOE is
responsible (e.g., the Fenune Osage Slough).
In response to a potential threat to the nearby St. Charles
County alluvial well field, management of contaminated surface
water is the first of these five components being addressed. This
well field supplies drinking water to more than 60,000 residents of
St. Charles County. It is located within 1.6 km (1 mi) of the
quarry. The quarry pond is providing a hydraulic gradient for
contaminant migration into the local groundwater because the pond
surface is higher than the nearby groundwater table.
mqbwrod.qrd/jaj 15
-------
QUARRY
Bulk Wastes
Contaminated
Groundwater
Pond Water
Contaminated
Vicinity Properties
Residual Materials
FIGURE 6
ENVIRONMENTAL COMPLIANCE COMPONENTS FOR
THE WELDON SPRING QUARRY
-------
. • -till*
The expedited response action for / component has been
documented in an engineering evaluation/cost analysis (EE/CA)
report. The alternative selected as a result of the EE/CA process,
which included public review and comment, was to treat the ponded
water in a facility constructed adjacent to the quarry and release
the treated water to the Missouri River in compliance with a permit
issued to the DOE by the Missouri Department of Natural Resources.
The action is expected to be initiated in 1991 and will continue
until subsequent decisions are implemented for a permanent solution
at the quarry.
The purpose of the quarry bulk waste OURA is to minimize the
potential for further migration of contaminants from the quarry
into the environment and to facilitate overall site cleanup by
making it possible to assess the extent of residual contamination
in the quarry and identify pathways for migration of contaminants
from the quarry. The bulk wastes constitute the source of
contaminants that are being released into the air at the quarry and
which are migrating through the fractured walls and floor of the
quarry into the underlying groundwater.
The comprehensive response actions for residual materials,
groundwater, and vicinity properties can be developed only after
the bulk wastes are removed from the quarry so that the nature and
extent of residual contamination and migration pathways can be
fully assessed. These actions, which will address final quarry
cleanup criteria, will be developed in consultation with EPA Region
VII and the State of Missouri and will be described in future
documents on the quarry.
w*qbwrod.qrd/jij
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5 SITE CHARACTERISTICS
5.1 SETTING
The Weldon Spring quarry is situated in a relatively remote
location along Missouri State Route 94 about 6.4 km (4 mi) south-
eouthwest of the chemical plant area and about 8 km (5 mi)
southwest of the city of Weidon Spring. The quarry is surrounded
by the Weldon Spring Wildlife Area, which is managed by the
Missouri Department of Conservation and is open throughout the year
to the general public for a variety of recreational uses. This
wildlife area is largely undisturbed, heavily wooded, and contains
regions of heavy underbrush. Vegetation at the quarry consists
primarily of grasses, shrubs, and trees. Agricultural crops are
grown on much of the land south of the quarry. Access to the
quarry is restricted by a 2.1-m (7-ft) high chain link fence which
is topped by three strands of barbed wire. This fence completely
surrounds the quarry.
The quarry was excavated into a limestone bluff of the
Kiwnswick Limestone Formation that forms a valley wall at the edge
of the Missouri River floodplain; this limestone formation contains
numerous cracks and fissures. The quarry is about 300 m (1,000 ft)
long by 140 m (450 ft) wide and covers an area of approximately
3.6 ha (9 acres). The main floor of the quarry comprises
approximately 0.8 ha (2 acres) and currently contains about 11,000
m3 (3,000,000 gal) of ponded water covering about 0.2 ha (0.5
acre). The Missouri River is located approximately 1.6 km
(1 mi) to the southeast. Nearby streams include Little Femme Osage
Creek to the west, an unnamed tributary of Little Femme Osage Creek
to the north, and Femme Osage Creek to the southwest. The Femme
Osage Slough is located about 210 m (700 ft) south of the quarry
(Figure 4). *.
Mqbvrod.qrd/jij 18
-------
The quarry borders the Missouri River alluvial floodplain.
The surrounding topography, except for the floodplain area to the
south/ is rugged, heavily wooded, and characterized by deep
ravines. The surface elevation of waste in the quarry is about
145 m (480 ft), and the elevation of the quarry rim is about 170 m
(550 ft) mean sea level (KSL). The average surface elevation of
the water ponded in the quarry is about 142 m (465 ft) MSL. A
pyramid-shaped limestone hill rises from the quarry floor to an
elevation of about 158 m (518 ft) MSL. The upper elevations at the
quarry are well above the Missouri River floodplain. The quarry
was originally excavated to a bottom elevation of approximately
136 m (446 ft) KSL.
The ponded quarry water is hydraulically connected to the
local groundwater system in the underlying fractured bedrock, and
its elevation appears to be a hydrologically high elevation for the
vicinity. Most of the groundwater flow from the quarry is
transported by the local gradient toward the alluvium of the
Missouri River floodplain. The connection between the fractured
limestone aquifer beneath the quarry and the unconfined alluvial
aquifer near Femme Osage Slough is not clearly understood.
Although it is certain that groundwater flows toward the Missouri
River from the quarry, the influence of Femme Osage Slough on this
flow and the associated solute transport is uncertain. It appears
that the clay and silty alluvium at the slough may act as a
groundwater barrier. Although at present there is no evidence of
groundwater flow through the alluvial material below the slough to
the alluvial aquifer, the existing groundwater monitoring system
will be expanded. Groundwater velocity in the bedrock below the
alluvium is not known.
The St. Charles County well field lies between the quarry and
the Missouri River; it is separated from the quarry by the Femme
Osage Slough (Figure 4). Monitoring wells located between the
quarry and the well field are sampled routinely in order to monitor
vsqbwrod.qrd/j«j 19
-------
for both chemical and radiological contaminants. Groundwater in
the unconfined alluvial aquifer south of Femme Osage Slough is not
radioactively contaminated; concentrations of radioactive
constituents in samples from this aquifer are within the typical
background range for this region. However, nitroaromatic compounds
have been detected at low levels (less than 1 |ig/l) in groundwater
south of the slough. These compounds have been detected
sporadically in 5 of the 10 DOE monitoring wells located south of
the slough.
i-.
Nitroaromatic compounds have not migrated to the county well
field. Nitroaromatic compounds detected south of the slough may be
the result of contamination in slough sediments due to discharges
of nitroaromatically contaminated wastes into Little Femme Osage
Creek during World War II, past pumping tests on the quarry pond in
which pond water was -discharged directly into Little Femme Osage
Creek, or transport via the groundwater pathway. (Femme Osage
Slough was formerly a portion of Femme Osage Creek and received
water from Little Femme Osage Creek prior to discharge to the
Missouri River.)
The alluvial aquifer south of Femme Osage Slough appears not
to be contaminated with uranium. Monitoring will be expanded to
establish solute concentrations and groundwater flow directions in
the deeper bedrock aquifer.
5.2 WASTE CHARACTERISTICS
The materials disposed of in the quarry consist of wastes from
the chemical plant as well as wastes brought in from other areas in
the past, including (1) materials associated with the processing of
uranium and thorium concentrates, (2) uranium- and radium-
contaminated rubble, (3) high-thorium-content materials (most of
which were subsequently removed from the quarry for the purpose of
recovering rare earth elements), and (4) 3.0% thorium residues.
w«qbwrod.qrd/jij 20
-------
Most of the estimated 73,000 m3 (95,000 yd5) of bulk wastes in the
quarry is radioactively contaminated. The radioactive contaminants
of concern are those associated with the uranium-238 and thorium-
232 decay series (Figures 7 and 8).
Radioactive contamination on the main floor of the quarry
covers an area of almost 5,600 m2 (60,000 ft2) and extends to depths
of about 12 m (40 ft); radioactive contamination in the entire
quarry covers an area of about 15,900 m2 (171,000 ft2) and extends
to an average depth of about 4 m (13 ft). The locations and depths
of radioactive contamination at the quarry are shown in Figures 9
and 10. The concentrations of the major radionuclides in the
quarry wastes are summarized in Table 2.
In each of the uranium-238 and thorium-232 decay series, one
member of the series is a gas (radon-222 and radon-220,
respectively). Elevated concentrations of radon-222 and radon-220
and their short-lived decay products have been measured in the
atmosphere within the quarry and at the quarry fence. The average
concentration of radon gas (radon-222 and radon-220) in the
atmosphere within the quarry is 14 pCi/1 based on previous measure-
ments. The annual average concentration at the fence line varies
from year to year and has averaged about 2 pCi/1 over the past few
years. The background concentration of radon gas in the Weldon
Spring area is about 0.3 pCi/1.
As radionuclides decay, they emit various types of radiation;
certain of these can traverse environmental media and penetrate
human skin. Hence, close proximity to radioactive materials can
pose hazards to individuals without actual uptake by the body
(i.e., through ingestion or inhalation). The most energetic form
of electromagnetic radiation emitted by radionuclides is the gamma
»
ray. Elevated gamma exposure rates have been measured at the
quarry fence and within the quarry. The highest measured gamma
mqbwrod.qrd/jij 21
-------
NOTES:
Only the dominant d«cay mode
is shown.
The times shown ire haft-lives.
The symbols o and B indicate
alpha and beta decay.
An asterisk indicate* that the
iaotopa is also a gamma
•miner.
Radon-222*
o
1
1 Pofomum.214*
36 days
e
i .
20 minuies
Polonium-218
o
*
Laad
BismuBv214*
31 ''
minuies $
27 minutes
r
2H* _
1
1 -
a
^
160
micro-
seconds
(
Polonijm-2iO*
/ .
B
Sdays
Bismuth-210
i
J
0
22 years
^
sd-210*
140 flays
t
Lead-206 (stable/
FIGURE 7
URANIUM-238 RADIOACTIVE DECAY SERIES
-------
Thorium-232
a
>
14 baiior
years
8
5.
Radium-226
NOTES:
Only the dominant decay mode
is shown.
The times shown are half-lives.
The symbols a and 0 indicate
alpha and beta decay.
An asterisk indicates that the
isotope is also a gamma
•miner.
FIGURE 8
THORIUM-232 RADIOACTIVE DECAY SERIES
-------
1
\
n Area of Confirmed
Padioachve Contamination. 0-05 fl
FIGURE 9
SURFACE RADIOACTIVE CONTAMINATION AT THE QUARRY
-------
f— FvnmUrw
n *«w» ol Confirmed Suteurfaoe fl>rJoac
-------
TABLE 2 Concentration! of ftadionuclides in the Quarry Bulk Hastes
ftadionuclide
uraniua-238
ThoriuM-238
Thoriu»-230
RadiuM-228
Nadiua>-226
Bulk Waste concentration
(pCi/g>
Range Average
1.4
0.7
0.7
0.1
0.2
- 2,400
36
- 6.600
- 2,200
- 2,800
200
26
330
96
110
Average Surficial
Concentration*
(pCi/g)
170
(b)
1SO
20
110
Average
Background
Concentration'
(PCi/g)
1.3
1.0
1.3
1.0
0.9
* Staples obtained frc* the top 15 c* (6 in.) of the quarry bulk wattes. »'•
b No data available.
exposure rate at the quarry fence is about 8 jiR/hr above
background; the background gamma exposure rate in the Wei don Spring
area is about 10 nR/hr. The gamma exposure rate within the quarry
averages 60 jiR/hr; the maximum measured rate is 625 pR/hr.
Nonradioactive contaminants in the quarry bulk wastes are
consistent with those expected from the disposal history. Both the
type of waste material present and the contaminant concentrations
in this material are highly variable. As part of the radiological
characterization conducted in 1984 and 1985, one surface and six
subsurface samples were collected for nonradiological analysis.
These samples were analyzed for priority pollutant metals, organic
compounds, cyanide, and other selected compounds. Some organic
contaminants and elevated levels of some metals were detected.
Results for contaminants that were measured above detection limits
are summarized in Table 3.
A more extensive chemical characterization study was conducted
at the quarry in 1986 when samples were taken from 17 boreholes.
The depths of the boreholes were highly variable, ranging from
0.61 m (2 ft) to 12 m (40 ft). The borehole locations were
*
selected on the basis of historical data on waste disposal at the
quarry.
vtqbvrod.qrd/jaj
26
-------
TABLE 3 Concentration, of Cheaiicals Detected In the Quarry Bulk Haste* in the 1984-1985
Characterization Study and Background Concentrations in Missouri Soils
Composite Borehole Sample
Concentration (aq/kq)
Chmical*
Priority Pollutant
HetBls and Cyanide
Antinony
Arsenic
Berylliusi
Cadmiu*
Chromium
Copper
Lead
Mercury
Nickel
Selenium
Silver
Thai Him
line
Cyanide
Organic Priority
Pollutants
•-Benzene hexachlorlde
S-Benzene hexachlorlde
y-Benzene hexachlorlde
(Hndane)
PCB* (Aroclor 1254)
PCBt (Aroclor 1260)
Other Organic Pollutants
2-Pentanone-4-hydroxy-
4-nethyl (diacetone
alcohol)
2-Nethylnaphthalene
Rangeb
<20d
73-120
0.45-0.83
1.8-98
19-49
38-160
130-410
0.18-6.3
19-120
17-28
5.8-8.3
3.0-6.2
68-870
0.2-0.6
0.0051-0.0053
0.019-0.095
0.0013
0.56-46
9.0
|_
2-6h
0.67
Nuafcer of
Boreholes in
. which Chemical
Average Detected
100
0.62
19
30
100
280
2.0
43
23
7.0
4.7
340
0.38
0.00529
0.0459
0.00139
12
9.0
L
4.6h
0.67
0
6
6
6
6
6
6
6
6
6
3
6
6
5
2
3
1
5
1
5
1
Surface
Saaple
Concentration
(•B/kfl)
71
100
0.61
2.0
24
140
950
0.7
300
22
7.5
5.1
39
0.2
.
0.0035
—
1.0
-
14"
j
<0.06d
Average
Background
Concentration0
(•o/kg)
-------
e NA Meant data not available.
The 29 volatile priority pollutants Measured for were not detected at a sensitivity level of 20 sg/kQ- Thirteen sesilvolatlle organic compounds
were detected In on borehole; these compounds are indicated in Table * (identified by footnote f). The presence of PCDs prevented the detection of
•ost pesticides.
0 Concentrations of a. 8, and y-beniene hexachloride, were reported for only 2, 3. and 1 of the borehole sasples. respectively.
h Estimated concentrations.
wsqbwrod.qrd/ja) 28
-------
Nitroaromatic compounds, polychlorinated biphenyls (PCBs), and
polynuclear aromatic hydrocarbons (PAHs) were detected in these
samples. The results of this study are summarized in Table 4.
Because of the heterogeneous nature of the wastes and the limited
number of samples taken, the results are expected to be indicative
of., rather than representative of, the wastes present in the
quarry.
Three surface samples were collected in May 1987 from an area
in the northeastern corner of the quarry where surficial discolor-
ation suggested the presence of nitroaromatic compounds. Various
nitroaromatic compounds were detected in the samples. The compound
2,4,6-TNT was detected at an average concentration of 13,000 mg/kg.
The results of the analyses for nitroaromatic compounds are
summarized in Table 5.
These characterization results indicate that chemical
contamination is present throughout much of the quarry bulk wastes
and that the distribution of the contaminants is highly
heterogeneous. However, general locations of various waste types
can be defined in some cases. For example, nitroaromatic compounds
are found in the eastern end of the quarry, which is consistent
with the disposal history. The PCBs do not show a defined pattern
of distribution but are typically limited to near-surface depths
(0 to 1.8 m [0 to 6 ft]). Most chemical contaminants are found at
depths of less than 3.6 m (12 ft).
tftqbwrod.qrd/jij 29
-------
TABLf 4 Concentration* of CheBicals Detected in the Quarry Bulk Metes
in the 1986 Characterization Study
Chemical*
Concentration
(•q/kfl) Number of Boreholes
. .In which Chemical
Range Average0 Detected0
d,e
Volatile Compounds
Acetone
2-Butanone
Ethylbenzene
Hethylene chloride
Toluene
Total xylenes
Trichloroethene
Semivolatile Compounds *
Acenaphthene.
Dibenzofyran
Fluorene ,
Phenanthreoe
Anthracene .
Fluoraothene
PyreneT .
fienz (a) ao thracene
Chrysene .
Benzo(b)fluorenthene!
Benzo(k)fluoranthene
Benzo(a)pyrene
Indeno(1,2>3-cd)pyrene
Dibenz(a,h)anthracene
Benzo(g.h.i}perylene
2,*-DNT«
2.6-DHT*
Oi-n-botylphthalete
Bit(2-ethylbexytJphthalate
Naphthalene
PCBs c
Aroclor 1254
Aroclor 1260
Mitroaronafic Compounds
2,6-Oiaaino-4-nitrotoluene
2,4,6-TNT
2.4-DKT?
2.6-ONT1
2,4-Oiaaino-6-nitrotoluene
1.4-52
0.86-1.7
0.68-1.8
0.79-6.4
0.75
0.66-1.4
0.9
1.7-18
1.4-3.6
6.6-19
0.73-150
0.34-37
0.78-190
0.68-170
0.53-86
0.46-89
0.62-110
0.78-0.98
0.46-68
0.45-49
0.33-17
0.41-50
1.7-10
0.53-3.7
0.47-0.56
0.66-1.6
1.3
0.46-120
9.1-12
0.33-0.58
0.38-1600
0.46-33
0.36-68
1.3-7.3
13
1.4
0.99
2.9
0.75
0.95
0.9
7.6
2.5
13
26
9.7
24
23
15
13
17
0.88
11
9.3
2.9
10
6.3
1.6
0.53
1.0
1.3
21
11
0.47
260
8.1
9.5
4.8
6
2
8
8
1
2
1
4
2
2
6
6
6
6
6
6
6
2
6
6
4
6
1
1
2
3
1
9
1
3
6
3
3
2
* All compounds that had one or acre positive results above detection liait* are listed; concentrations are
rounded to two significant figures. Saaplei were taken In the last quarter of 1986 fro* 17 boreholes in
the bulk wastes.
b Ranges and averages are for detected values only and do not necessarily Indicate the average
concentration for the entire waste Mterial.
c Detection of a chemical indicates that the specie* was detected in at least one Incremental sample fro* a
borehole. Each incremental saaple was not necessarily tested for all cheaical species.
d Except for trichloroethene, all of the volatile compounds detected in the saaples were also detected in
•ethod and field blanks.
wsqbwrod.qrd/jij
30
-------
e Analyses for volatile organics, te»ivolitUe organics. and PCBi were performed in accordance with the EPA
Contract Laboratory Program.
This compound was alto detected in the 1984-1985 investigation by Bechtel National, Inc.
" This compound is also listed in this table under nitroaroaatic compounds (see footnote i).
h Analyses for nitroaroutic compounds were performed according to Method 4B of the U.S. Army Toxic and
Hazardous Materials Agency using high-pressure liquid chroMtography.
1 This compound is also listed in this table under semivolatile compounds. Split samples were analyzed in
accordance with the EPA Contract Laboratory Program and Method 4B of the U.S. Army Toxic and Hazardous
Materials Agency.
wsqbwrod. qrd/ j a j 31
-------
TABLE 5 Concentrations of Nitroarooatic Coapound* in Surface Soils at the Quarry*
Concentration
NitroaroMtic
Compound
2.4,6-TNT
2,4-DNT
2.6-OKT
Nitrobenzene
1,3,5-Trinitrobenzene
1.3-Dinitrobenzene
(•B/kfl)
Ranee
4.900-20,000
6.6-29
<1.2-8.6
8.4-130
18-280
<0.8b
Average
13,000
18
5.0
78
140
* Three surface saapt.es were taken froa the exposed slope in the
northeastern corner of the quarry.
b Lower liait of detection.
Mqbwrod. qrd/ j a j
32
-------
6 SUMMARY OP SITE RISKS
A baseline risk evaluation was prepared to assess the
potential risks associated with the contamination present at the
quarry. Risk assessment is a key component of the RI/FS process
and is typically conducted for the baseline (no-action) case to (1)
determine potential impacts to human health and the environment,
(2) support the determination of appropriate cleanup criteria, and
(3) provide A basis for -evaluating the effectiveness of proposed
remedial action alternatives. However, because management of the
bulk wastes is a focused interim action of the overall remedial
action for the quarry, the scope and purpose of this assessment was
less comprehensive than that generally performed in a baseline risk
assessment. Because site characterization data on the nature and
extent of the contamination and the pathways and mechanisms for
contaminant migration from the quarry is limited, a comprehensive
baseline risk assessment could not be prepared. For this reason,
the assessment was referred to as a baseline risk "evaluation," to
distinguish it from the more comprehensive baseline risk
"assessment." The analyses in this risk evaluation were carried
out to meet, within the limits of available data, the first of the
three objectives of a risk assessment, i.e., to assess the
potential impacts on human health and the environment. The scope
of the evaluation was limited to an assessment of the potential
risks associated with the bulk wastes. It addressed exposures that
could occur in the short term under existing site conditions.
Risks will be assessed further as part of other RI/FS processes
before the wastes are finally disposed of and the overall
remediation of the quarry is completed.
6.1 CONTAMINANT IDENTIFICATION
The BRE identified those radionuclides and chemicals present
in the quarry bulk wastes that pose the greatest potential risk to
human health. The radioactive contaminants of concern (i.e.,
vcqbwrod.qrd/jaj 33
-------
indicator radionuclides) are those associated with the uranium-238
and thorium-232 decay series (see Table 2 and Figures 7 and 8).
The radiological hazards of the various radionuclides in these
series were determined from the activity concentrations of uranium-
238 / thorium-232, thorium-230, radium-228, and radium-226 and from
measured values of radon-222, radon-220, and their short-lived
decay products. The risks associated with gamma radiation were
also assessed.
\:
The indicator chemicals were selected from contaminants
detected in the wastes (see Tables 2, 3, 4, and 5). They were
selected mainly on the basis of their toxicological properties and
their concentrations in surface soils at the quarry. (Under
current site conditions, the only complete exposure pathways at the
quarry result from surface soil contamination.) The indicator
contaminants for the BRE were nitroaromatic compounds (2,4,6-TNT,
2,4-DNT, 2,6-DNT, and 1,3,5-trinitrobenzene), metals (arsenic,
lead, nickel, selenium, and uranium), PCBs, and PAHs. Of these
contaminants, TNT, ONT, arsenic, lead, nickel, PCBs, and PAHs are
considered to be potential carcinogens.
6.2 EXPOSURE ASSESSMENT
The key factors considered in developing the exposure pathways
at the quarry include (1) the quarry is fenced, closed to the
public, and surrounded by wildlife areas; (2) the nearest residence
is 0.8 km (0.5 mi) west of the quarry on State Route 94; and (3) no
remedial action activities are currently taking place at the
quarry. The exposure assessment in the BRE was based on current
land-use conditions and contaminant concentrations.
The main source of contamination within the quarry is the bulk
wastes, and the exposure pathways'considered in the risk evaluation
are those directly associated with these wastes. It has been shown
that the groundwater at the quarry contains elevated concentrations
vcqtMTOd.qrd/jaj 34
-------
of chemical and radioactive contaminants, but this water is not a
drinking water source. The groundwater south of the quarry and at
the nearby St. Charles County well field is monitored routinely,
and mitigative measures would be taken if elevated concentrations
were detected in the well field. Thus, because there are no known
or indicated points of current exposure, the groundwater pathway is
incomplete and was not considered in the BRE. The potential risks
associated with contaminated groundwater will, however, be
addressed an the -comprehensive risk assessment to ±>e prepared
following implementation of the bulk waste . remedial action and
completion of detailed characterization of the quarry area. Mo
private residences or other structures are located within the area
that could be impacted by releases from the quarry.
Based on an evaluation of waste characteristics and potential
release mechanisms, the BRE identified the principal contaminants
at the quarry to which individuals could be exposed and the
potential routes of human exposure to these contaminants as:
o Inhalation of radon-222, radon-220, and their
short-lived decay products.
o Exposure to external gamma radiation.
o Inhalation of radioactively and chemically
contaminated airborne dusts.
o Dermal contact with chemically contaminated surface
soils.
o Ingestion of radioactively and chemically
contaminated surface soils.
*
• *
Scenarios of human activities that could result in exposures
by these pathways were developed for individuals temporarily
vtQbwrod.qrd/jij 35
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occupying the impacted area. "Passerby" and "trespasser" scenarios
were evaluated. These scenarios were realistic but conservative.
descriptions of activities that could result in human exposures to
quarry contaminants. Under each scenario, two "cases" were
developed to estimate "representative" exposure and "plausible
maximum" exposure.
The passerby scenario considered potential exposures to an
individual who routinely walks by the northern boundary of the
quarry along State Route 94. For the representative exposure case,
it was assumed that the individual walks by the quarry twice per
day, 250 days per year over a period of five years; for the
plausible maximum exposure case, the exposure period was increased
to 365 days per year over a period of 10 years. The exposure
pathways evaluated for this scenario were inhalation of radon-222
and radon-220 and their short-lived decay products, exposure to
external gamma radiation, and inhalation of dusts contaminated with
nitroaromatic compounds and uranium. (Nitroaromatic compounds and
uranium are the only contaminants found in exposed areas of the
quarry that are subject to fugitive dust emissions.)
The trespasser scenario considered exposures to a youth who
enters the quarry several times per year. For the representative
exposure case, it was assumed that an individual (11 to 15 years
old) enters the quarry, remains there for a period of two hours,
and repeats this activity 12 times per year over a period of five
years. For the plausible maximum exposure case, it was assumed
that an individual (9 to 18 years old) enters the quarry once per
week for a period of four hours, 50 weeks per year over a period of
10 years. The exposure pathways evaluated for the trespasser
scenario included the same pathways considered for the passerby as
well as direct contact with contaminated soils, which could result
in dermal absorption of the organic indicator chemicals and
incidental ingestion of all compounds.
vtqbwrod.qrd/jij 36
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The conditions of the passerby scenario were selected to
represent (1) the exposure occurring at the location of highest
off-site radon and airborne particulate concentrations (along State
Route 94) and (2) a frequency and duration of exposure (i.e.,
daily, for a total duration of 24 minutes) that, over the long
term, would not be exceeded by an individual routinely entering any
area impacted by contaminant releases from the quarry. Thus,
although other potential receptors were identified (e.g.,
individuals driving ±>y the quarry -on State Route 94 or a hiker on
the Missouri River State Trail), they were not explicitly evaluated
because their exposures would be similar to, or less than, the
exposures estimated for the passerby. Although access to the
quarry is restricted by a chain-link fence, the area is not
guarded, hence it is reasonable to assume that a trespasser could
enter the contaminated area. The trespasser scenario is considered
to be a conservative estimate of potential exposures to any
individual coming into direct contact with the contamination in the
quarry.
6.3 POTENTIAL HEALTH RISKS
The BRE assessed the radiological and chemical health risks
resulting from potential exposures to the quarry contaminants under
current site conditions. Health effects resulting from radiation
exposure were evaluated in terms of the increased likelihood of
inducing fatal cancers and serious genetic effects in future
generations. The risk of cancer induction from the radionuclides
present in the quarry bulk wastes is much greater than the risk of
serious genetic effects. The potential for adverse health effects
(other than cancer) from exposure to chemical contaminants was
assessed by dividing the estimated average daily intake by
established reference doses. This calculation determined the
•hazard index". A hazard index of less than 1 indicates a
nonhazardous situation while a hazard index greater than 1
indicates a potential for adverse health effects.
wsqbwrod.qrd/jtj 3?
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The estimated carcinogenic risks and hazard indexes for the
passerby and trespasser scenarios are summarized in Table 6. The
carcinogenic risks from radiation exposures range from 4.2 x 10~6
for the passerby representative exposure case to 8.7 x 10"5 for the
trespasser plausible maximum exposure case, and the carcinogenic
risks from chemical exposures range from 1.0 x 10"9 to 3.6 x 10*5,
respectively. The risk from radiation exposure exceeds that from
chemical exposure for both scenarios. The major exposure pathway
for the radiological risk in all cases is inhalation of radon-222
i-.
and its short-lived decay products. The major contributor to the
chemical carcinogenic risk for the trespasser is 2,4,6-TNT, which
accounts for approximately 40% of the risk; arsenic, PCBs, and PAHs
account for the remaining 60%.
The very low hazard indexes estimated for the passerby
scenario (less than 2 x 10*s) indicate that there is little
potential for noncarcinogenic health impacts to individuals outside
the quarry. However/ for the trespasser, the hazard index is 2.0
for the representative exposure case and 8.5 for the plausible
maximum exposure case. For both cases, the major contributor to
the noncarcinogenic hazard is exposure to 2,4,6-TNT. This is not
unexpected given the presence of this contaminant at concentrations
greater than 1% in surface soils at the quarry. The ^estimated
hazard indexes for 2,4,6-TNT are 1.7 and 7.2 for the representative
and plausible maximum trespasser exposure cases, respectively.
These results indicate the potential for the occurrence of adverse
health effects to an unprotected individual frequently entering the
quarry. However, under current site conditions in which access to
the quarry is restricted, it is unlikely that an individual would
routinely enter the quarry.
vsqbvrod.qrd/j«j 38
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TABLE 6 Carcinogenic licks and Health Hazard Intern for the Passerby and Trespasser
Scanario*
Health Hazard
Careinooenie Risks Index for
Exposure Scenario/Case
Passerby
Representative
Plausible maximum
Trespasser
-Representative
Plausible maximum
Radiological'
4.2 x !0lf
1.2 x 10
6.0 x 1olf
8.7 x 10
. Noncarcinogenic
Chemical" Effects0
1.0 x I0l£
3.0 x 10
4.3 x 1olf
3.6 x 10
1.0 x 101
1.6 x 10
2.0
8.5
* Risk of a fatal cancer; the rate of cancer induction will be higher.
b Rate of cancer induction. The NCP establishes that, for known or suspected
carcinogens, acceptable exposure levels are generally concentration levels
that represent an excess upper bound lifetime cancer risk to an individual
of between 10 and 10 using Information on the relationship between dose
and response.
c The health hazard index is a measure of the potential for adverse
chronic health effects other than cancer. A value greater than 1 indicates
a potential for adverse health effects.
6.4 POTENTIAL ENVIRONMENTAL RISKS
The potential risks to the environment considered in the BRE
were impacts on soil resources, air quality, vegetation and
wildlife, and water resources. No adverse impacts have been
observed for soil resources, air quality, or vegetation and
wildlife as a result of the bulk wastes in the quarry. The major
impact that could result from gaseous releases, i.e., radon, is
addressed in the human health assessment portion of the BRE.
Water resources have been impacted by the presence of the bulk
wastes. The ponded water is already contaminated as a result of
contact with the bulk wastes, but incremental contamination from
continued contact, e.g., future surface runoff, is not expected to
significantly alter the existing water quality. Similarly, Femme
Osage Slough, south of the quarry,.already contains radioactive and
chemical contaminants. This contamination may have resulted from
subsurface migration from areas north of the slough and/or from
wsqbwrod.qrd/jaj 39
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past discharges into Little Fenune Osage Creek. Groundwater in the
vicinity of the quarry has been contaminated as a result of
contaminant migration from the bulk wastes. If the bulk wastes
remain in the quarry, contaminants could migrate farther into the
surrounding environment via the fractured limestone of the
Kimmswick Limestone Formation, and contaminant concentrations might
Increase in the vicinity of Fenune Osage Slough.
v*qbwrod.qrd/j*j 40
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7 POTENTIALLY APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS
Section 121(d)(2) of CERCLA requires that for any hazardous
substance, pollutant, or contaminant that remains on site, the
remedial action must attain a level or standard of control at least
equal to requirements, criteria, or limitations under Federal
environmental laws or more stringent State environmental lavs or
facility siting laws which are legally Applicable or relevant end
appropriate (ARAR) under the circumstances of the release or
threatened release at the completion of the remedial action.
Furthermore, the NCP requires attainment of ARARs during
implementation of a remedial action when an ARAR is pertinent to
the action itself as well as at the completion of the action.
Under certain conditions, compliance with these ARARs may be
waived.
The limited scope of the quarry bulk waste operable unit
remedial action, including the fact that it is not the final
remedial action for either the bulk wastes or the quarry, was
considered in analyzing potential ARARs.
A number of Federal and State environmental laws were
evaluated as to legal applicability or relevance and
appropriateness to the circumstances of the releases and threatened
releases at the quarry. Those requirements considered to be most
likely to be applicable or relevant and appropriate to the remedial
alternatives under consideration are discussed below.
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7.1 FEDERAL ENVIRONMENTAL LAWS
7.1.1 Resource Conservation and Recovery Act
Subtitle C of the Resource Conservation and Recovery Act
(RCRA) regulates the generation, transportation, treatment, storage
and disposal of hazardous wastes as defined in 40 CFR 261. RCRA
includes several requirements that might be applicable or relevant
and appropriate to the remedial action Alternatives under
consideration, including requirements and standards pertaining to
closure of . hazardous waste management units, groundwater
monitoring, location standards, minimum technology requirements,
land disposal restrictions, and unit design and operating
standards.
Under 40 CFR 261, a solid waste is a regulated hazardous waste
if it is not otherwise excluded from regulation as a hazardous
waste and exhibits any of the characteristics identified in 40 CFR
261 Subpart C, or is listed in 40 CFR 261 Subpart D, or is a
mixture of a solid waste and a hazardous waste listed in 40 CFR 261
Subpart D.
RCRA hazardous waste management requirements would be legally
applicable to this remedial action if a combination of the
following conditions were met:
1. The waste is a regulated hazardous waste, as
described above, and either
2a. The waste was treated, stored, or disposed of after
the effective date of the RCRA requirements, or
2b. The activity at • the CERCLA site constitutes
*
treatment, storage, or disposal as defined by RCRA.
Mqbwrod.qrd/jaj 42
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Although the quarry bulk wastes were not treated, stored, or
disposed of after the effective date of RCRA, some of the remedial
alternatives considered would include activities currently
regulated by RCRA if the bulk wastes are RCRA hazardous wastes.
Therefore, an evaluation of the applicability of RCRA Subtitle C
requirements to the various response alternatives must include a
determination as to whether the bulk wastes are RCRA regulated
hazardous wastes.
In order to determine if the quarry contains listed wastes, it
is necessary to consider information as to the source of the
wastes. Based on the source of the quarry bulk wastes, the
materials disposed of in the quarry could have included the
following hazardous wastes that are listed in 40 CFR 261 Subpart D:
o K-044 listed wastes, which are defined as wastewater
treatment sludges from the manufacturing and processing
of explosives.
o K-047 listed wastes, which are defined as pink/red
water from TNT operations.
o U-105 listed waste, which is the commercial chemical
product, manufacturing intermediate, or off-
specification commercial chemical product
2,4-dinitrotoluene.
o U-106 listed waste, which is the commercial chemical
product, manufacturing intermediate, or off-
specification commercial chemical product
2,6-dinitrotoluene.
An extensive document search* was conducted of all available
records and reports pertaining to the sources of the wastes
disposed of in the quarry. While the results of this search
vsqbwrod.qrd/jij 43
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indicate that both vastevater treatment sludges from the
manufacturing of explosives and pink/red water from TNT operations
were generated at the Weldon Spring Ordnance Works facility, no
information was found to substantiate that such wastes were
disposed of in the quarry. Furthermore, there is no information to
suggest that commercial chemical products, manufacturing
intermediates, or off-specification commercial chemical products
2,4-dinitrotoluene or 2,6-dinitrotoluene were disposed of in the
quarry. It is concluded, therefore, that the quarry "bulk wastes
i-.
are not a listed hazardous waste under RCRA.
None of the quarry bulk waste samples tested to date have
exhibited any of the RCRA hazardous waste characteristics.
Therefore, the DOE considers the quarry bulk waste not to be a RCRA
characteristic hazardous waste, and the RCRA Subtitle C
requirements are not legally applicable. This testing is not
conclusive, however, given that the heterogeneity of the waste mass
precludes representative sampling of the in-place material. In
addition, the EPA has recently established an additional RCRA
characteristic test (Toxicity Characteristic Leaching Potential
[TCLP]) which has not yet been performed on the waste material.
However, even if these requirements are not legally applicable
to the response action, they may be relevant and appropriate to the
circumstances of the release or threatened release. A
determination of relevance and appropriateness includes
consideration of a number of factors, including the purpose of the
requirement and the purpose of the CERCLA action, the medium
regulated or affected by the requirement and the medium
contaminated or affected by the CERCLA site, the substances
regulated by the requirement and the substances found at the CERCLA
site, and the actions or activities regulated by the requirement
and the remedial action contemplated at the CERCLA site.
vsqbwrod. qrd/j • j 44
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The available data indicate that the DNT contaminated soil and
debris in the quarry is present in low concentrations and dispersed
in soil over a wide area. Thus, even though some hazardous
constituents are present in the quarry bulk wastes, the low
concentrations and the physical and chemical condition of the
contaminated soils and debris matrix of the wastes are inherently
different from what was envisioned by RCRA. Therefore, the DOE
does not consider RCRA Subtitle C requirements to be relevant and
appropriate on the basis of similarity of the wastes present at the
site to a RCRA listed waste.
However, some of the wastes present in the quarry may exhibit
characteristics similar to RCRA hazardous wastes. Furthermore,
some of the remedial alternatives under consideration for the
quarry are similar to some of the hazardous waste actions regulated
by RCRA. Therefore, in analyzing the various remedial alternatives
for compliance with ARARs, the DOE will consider whether RCRA
requirements for hazardous wastes are relevant and appropriate.
Prior to selection of the final remedial action for treatment
and/or disposal of the quarry bulk wastes, additional tests will be
performed once the wastes have been placed in storage to establish
more definitively whether the quarry bulk wastes are RCRA
characteristic hazardous wastes. This information will then be
considered in future decision making processes regarding subsequent
management of the quarry bulk wastes.
7.1.2 Safe Drinking Water Act
Potential ARARs under the Safe Drinking Water Act (SDWA)
include Maximum Contaminant Levels (MCLs) and Maximum Contaminant
Level Goals (MCLGs). MCLs are enforceable standards which apply to
public drinking water supplies. . MCLGs are unenforceable health
based goals for maximum contaminant levels in drinking water.
»«qbwpod.qrd/j»j 45
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Section 121(d)(2) of CERCLA requires on-site remedies to attain
MCLGs if they are relevant and appropriate to the release.
The DOE does not consider either MCLs or MCLGs to be
applicable or relevant and appropriate requirements for this action
since this operable unit remedial action does not address
groundwater remediation. MCLs and MCLGs will be evaluated as
potential ARARs during the decision making process for groundwater
at, and downgradient of, the quarry. »••
7.1.3 Clean Water Act
Potential ARARs under the Clean Water Act (CWA) include
Federal Water Quality Criteria, standards for discharge of wastes
to publicly owned treatment works (POTW), effluent limitations and
guidelines for discharges directly to waters of the United States,
and requirements for dredge and fill activities. The DOE does not
consider any of these requirements to be either applicable or
relevant and appropriate to this operable unit remedial action
because the action does not involve remediation of releases to
waters of the United States, discharges to either a POTW or to
waters of the United States, or dredge and fill activities.
Potential ARARs under the CWA will be evaluated during subsequent
remedial action decision making.
7.1.4 Clean Air Act
Potential ARARs under the Clean Air Act (CAA) include National
Emission Standards for Hazardous Air Pollutants (NESHAPs) and
National Ambient Air Quality Standards (NAAQS). The NESHAP
requirements are codified in 40 CFR 61 and the NAAQS requirements
are codified in 40 CFR 50. The NESHAP provisions of the CAA
authorize the Administrator of *. the EPA to establish emission
standards for hazardous air pollutants. The.NESHAP provisions
further limit the construction of new sources or modification of
Mqbwrod.qrd/jaj 46
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existing sources which will not be in compliance with such emission
standards. The NESHAP standards have been set for several
contaminants present in the quarry bulk wastes which are currently
being released into the air or which may be released during
remedial alternatives under consideration. These contaminants
include radionuclides, arsenic, and asbestos.
The standards for radionuclides in 40 CFR 61 are applicable to
remedial alternatives under consideration.
The standards for arsenic in 40 CFR 61 are based on glass
manufacturing, primary copper smelting, and arsenic trioxide and
metallic arsenic production. These standards are not applicable to
any aspect of this operable unit remedial action since the source
of the air emissions is not a source addressed by the regulations
defining the standard. Furthermore, after evaluating the purpose
of the requirement versus the purpose of the quarry response action
and taking into consideration the actions regulated by the
requirement versus the action contemplated for the quarry, the DOE
does not consider these standards to be relevant and appropriate.
The DOE considers other emission standards, such as the standards
found at 29 CFR 1910.1000 for compliance with the Occupational
Safety and Health Act (OSHA), to be better suited to the remedial
alternatives under consideration.
The asbestos standard in 40 CFR 61 requiring no visible
emissions is considered to be applicable to some of the remedial
alternatives under consideration.
The CAA provides for the promulgation of two types of KAAQs,
i.e., primary and secondary standards, which apply to the ambient
air. Primary ambient air quality standards are standards which the
Administrator of the EPA finds to be necessary to protect public
health. Secondary standards are those standards which the
vcqbwrod.qrd/jej 47
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Administrator of the EPA finds are necessary to protect the public
welfare from the presence of air pollutants in ambient air.
The NAAQS are not ARARs because they do not apply directly to
source-specific emissions; rather they are national limitations on
ambient concentrations intended to protect public health and
welfare. The State of Missouri's Implementation Plan, however,
does provide source-specific emission limitations and is considered
to be an ARAR. This is discussed in Section 7.2.1 which considers
Missouri Air Quality Standards.
7.1.5 Toxic Substances Control Act
Potential ARARs under the Toxic Substances Control Act (TSCA)
include standards and requirements for the storage and disposal of
PCBs, for cleanup of PCB spills and for asbestos abatement
projects. PCB storage and disposal requirements are found in 40
CFR 761 Subpart D. TSCA PCB storage and disposal requirements
generally apply to PCBs at concentrations greater than 50 ppm; PCB
articles, e.g. transformers, capacitors, etc.; PCB containers with
concentrations greater than 500 ppm; and PCB spills greater than 50
ppm.
Any PCBs, PCB articles, and PCB containers in the quarry bulk
wastes would have been placed there prior to the effective date of
these regulations, so they would not be legally applicable to these
wastes as they presently exist. However, various remedial
alternatives under consideration could trigger the applicability of
these requirements.
The PCB Spill Cleanup Policy, found in 40 CFR 761 Subpart G,
establishes criteria to be used in determining the adequacy of the
cleanup of spills which occurred after May 4, 1987, which resulted
.*
in the release of materials containing PCBs at concentrations of 50
ppm or greater. Since any spills resulting from the presence of
MQbwrod.qrd/j«j 48
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PCBs in the bulk wastes occurred long before this date, the PCB
Spill Cleanup Policy is not applicable to this remedial action.
However, certain cleanup criteria in the PCB Spill Cleanup Policy
nay be considered relevant and appropriate to some aspects of some
of the remedial alternatives under consideration.
Various requirements pertaining to asbestos abatement projects
were promulgated at 40 CFR 731 Subpart G. These requirements
include limits on permissible exposures of workers to airborne
concentrations of asbestos during asbestos abatement projects,
requirements for asbestos removal, demolition and renovation
operations, and exposure monitoring. Since this operable unit
remedial action does not fit the regulatory definition of an
asbestos abatement project, these standards and requirements are
not legally applicable to the remedial alternatives under
consideration. The requirements do, however, include health-based
standards for asbestos exposure and may be considered relevant and
appropriate to certain aspects of some of the remedial
alternatives.
7.1.6 Atomic Energy Act
In regulations promulgated pursuant to the Atomic Energy Act
(AEA), radiation exposure limits and acceptable concentrations of
radionuclides in restricted and unrestricted areas are established
in 10 CFR 20. These standards are applicable only to activities
carried out under licenses issued by the U.S. Nuclear Regulatory
Commission (NRC). These requirements are not applicable to this
action since the DOE is not an NRC licensee. Although portions of
the requirements given in 10 CFR 20 could be considered relevant to
the quarry bulk waste remedial action, they are not appropriate
since the requirements are.based on radiation dosimetry models that
are out of date. The radiation protection requirements given in 10
CFR 20 are currently being revised to incorporate new radiation
dosimetry considerations. The requirements in DOE Orders for
mqbwrod.qrd/j(j 49
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radiation protection of individuals and the environment have
recently been updated and are comparable to those in proposed
revisions to 10 CFR 20. Remedial actions will be conducted in
compliance with DOE Orders for radiation protection which are more
up to date. Provisions in DOE Orders for radiation protection of
individuals and the environment are identified in Section 7.3 which
discusses "to be considered* requirements.
The revisions to 10 CFR 20 are expected to be promulgated
prior to removal of the bulk waste from the quarry. *" The
requirements in 10 CFR 20 will be reviewed following revision to
ensure that all substantive requirements are met. Any provisions
in the revised 10 CFR 20 that are more restrictive than
requirements in the DOE Orders for radiation protection will be
complied with.
Environmental Radiation Protection Standards for Nuclear Power
Operations are applicable to operations within the uranium fuel
cycle. These requirements are published in 40 CFR 190 under the
authority of the AEA. On the basis of jurisdictional
prerequisites, the standards are not applicable, i.e., the proposed
action is not part of the nuclear fuel cycle as defined in 40 CFR
190.02. Further, the requirements are considered relevant but not
appropriate since the intent is to regulate normal uranium fuel
cycle production operations and planned discharges. There are
variances in the requirements for unusual occurrences which would
include operations such as implementation of the proposed action.
Although these standards are not ARAR, it is DOE policy to maintain
exposures as low as reasonably achievable.
7.1.7 Uranium Mill Tailings Radiation Control Act
Pursuant to the Uranium Mill Tailings Radiation Control Act
(UMTRCA), various control standards for inactive uranium processing
sites have been promulgated. These standards were evaluated as
vcqbvrod.qrd/jaj 50
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potential ARARs for the quarry bulk waste remedial action. The
requirements are not applicable since the Weldon Spring site is not
a uranium mill tailings site. Furthermore, most of these
requirements are not considered to be relevant and appropriate to
this action primarily on the basis of consideration of the actions
or activities regulated by the requirement and the remedial action
contemplated at this site. For example/ 40 CFR 192.12(b)(l) and
40 CFR 192.12(b)(2) are considered not relevant nor appropriate
because no habitable buildings are involved in the remedial action.
40 CFR 192.12(a) might be relevant and appropriate to the
identification and management of residual materials in the quarry,
but this is beyond the scope of the proposed action. These
requirements will be evaluated as part of the follow-on remedial
actions planned for the quarry.
However, 40 CFR 192.02(b)(1), which addresses releases of
radon from tailings disposal piles, is considered to be relevant
and appropriate to those aspects of the remedial alternatives which
involve storage of the bulk wastes. At completion, the bulk waste
storage facility will have to meet the radon-222 flux standards
specified in 40 CFR 192.02(b)(1). This standard requires
reasonable assurance that radon-222 from residual radioactive
material will not (1) exceed an average release rate of 20
picocuries per square meter per second (20 pCi/m2/sec), or
(2) increase the annual average concentration of radon-222 in air
at or above any location outside the site perimeter by more than
one-half picocurie per liter (0.5 pCi/1).
7.1.8 Other Potential Federal ARARs
Other Federal laws, including the National Historic
Preservation Act, the Archeological Protection Act, the Endangered
Species Act, the Fish and Wildlife .Coordination Act, the Wilderness
Act, and the Wildlife Management Act,. will be evaluated as
potential ARARs in light of specific remedial action proposals.
Mqbwrod.qrd/jij 51
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7.2 STATE ENVIRONMENTAL AND FACILITY SITING LAWS
7.2.1 Migspyri Air Qualit S
The State of Missouri has adopted the NAAQS criteria specified
in the CAA through the State Implementation Plan. The State of
Missouri has promulgated ambient concentration standards under 10
CSR 10-6.010. Implementation of some of the remedial alternatives
could result in emissions of several of the criteria pollutants,
including particulate matter (50 |ig/m5 annual average or 150 jig/m3
over a 24 hour period) and lead (1.5 |ig/m3 quarterly average). As
stated earlier, ambient standards for these contaminants are not
ARAR; however they provide a sound technical basis for assuring
protection of public health and welfare during implementation and
will be considered for remedial alternatives involving potential
air releases.
7.2.2 Missouri Air Pollution Control Regulations
Various standards to control emissions of particulate matter
have been promulgated under Missouri air pollution control
regulations. The standards addressed in 10 CSR 10-5.050 are not
applicable nor relevant and appropriate since the source
definitions relate to industrial processes.
The standards addressed in 10 CSR 10-5.090 are not applicable
nor relevant and appropriate since the requirement applies to
single industrial source emissions.
The standards addressed in 10 CSR 10-5.100 are applicable to
the prevention of airborne particulate matter during construction
activities. The standard of control relates to "unnecessary
amounts of fugitive emissions'" and .minimizing complaints.
Particulate standards promulgated under 10 CSR 10-5.180 for
wqbwrod.qrd/jij 52
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internal combustion engines (no release for more than 10 seconds at
one time) are applicable during implementation.
7.2.3 Missouri Radiation Regulations
The Missouri Department of Health has issued Standards for
Protection Against Ionizing Radiation in 19 CSR 20. These
requirements are similar to those currently in 10 CFR 20. As
discussed in Section 7.1.6, these standards are based on radiation
dosimetry models that are out of date. The requirements in DOE
Orders for radiation protection of individuals and the environment
are more up to date. The quarry bulk waste remedial action will
therefore be implemented using DOE radiation protection
requirements.
There are, however, specific State requirements that are more
restrictive then Federal requirements, specifically a radon-222
concentration limit of 1 pCi/1 in uncontrolled areas. Baseline
data indicate that radon-222 levels in the area controlled by
fencing around the quarry render compliance with this requirement
unachievable during implementation of the action'based remedial
action alternatives. This requirement could be met upon completion
of the action based alternatives.
7.2.4 Missouri Hazardous Waste Management Laws
Missouri has adopted by reference a number of the RCRA
Subtitle C hazardous waste management regulations. To the extent
that State requirements are the same as Federal requirements, the
State requirements are not more stringent and will not be further
considered as ARARs. However, Missouri has also adopted some
requirements which are not identical to the Federal requirements,
including landfill siting requirements,, waste pile location
requirements, and storage facility lining'requirements, which may
be more stringent than Federal requirements. As discussed above
irtqfawrod.qrd/jij 53
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under potential RCRA ARARs, these State hazardous waste management
requirements are not considered legally applicable to the bulk
wastes, but may be relevant and appropriate.
7.2.5 Other Potential State ARARs
Other State laws will be considered in light of specific
remedial action proposals.
7.3 TO BE CONSIDERED REQUIREMENTS
The NCP provides that in addition to applicable or relevant
and appropriate requirements, other advisories, criteria, and
guidance may be considered for a particular release. DOE Orders,
which are not ARARs in that they are not promulgated standards
(e.g., public laws codified at the State or Federal level), provide
a sound basis for conducting this action. The DOE will implement
this action in compliance with all of its Orders, independent of
their evaluation as ARAR.
Two of the more significant Orders for this- action are DOE
Orders 5400.5 and 5480.11 which provide requirements for radiation
protection. The key elements of these Orders are as follows.
7.3.1 DOE Order 5400.5—Radiation Protection of the Public and
the Environment
The basic dose limit for protection of members of the general
public is 100 mrem/yr, above background, effective dose equivalent
from all exposure nodes. This dose is the sum of the effective
dose equivalent from all exposures to radiation sources external to
the body during the year plus the committed effective dose
equivalent from radionuclides taken into the body during the year.
Doses from specific exposure modes must comply with those required
by other Federal statutes such as the CAA and the SDWA. Further,
vsqtwrod.qrd/j*j 54
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all radiation exposures must be reduced to levels as low as
reasonably achievable.
The DOE derived concentration guides (DCGs) for airborne
radionuclides address protection of the general public from
airborne radioactive contaminants. The DCGs are concentrations
which, under conditions of continuous inhalation exposure for one
year, would result in an effective dose equivalent of 100 mrem.
The DCGs are provided in Chapter III of DOE Order 5400.5.
7.3.2 DOE Order 5480.11—Radiation Protection for Occupational
Workers
The effective dose equivalent received by any member of the
public entering a controlled area is limited to 100 mrem/yr above
background. In addition, exposures shall not cause a dose
equivalent to any tissue (including the skin and lens of the eye)
to exceed 5 rem/yr. The limits for assessed dose from exposure of
workers to radiation are shown on Table 7. (These values represent
maximum limits; it is DOE policy to maintain radiation exposures as
far below these limits as is reasonably achievable.)
vtqbvrod.qrd/j*j 55
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TABLE 7 Radiation Protection Standards - Ll«1t1ng Values
for Assessed Dose fro* Exposure of Occupational
Workers to Radiation
Annual
Dose Equivalent
Radiation Effect (re*)
Stochastic effects 9*
Monstochastic effect*
Lens of eye 15
Organ, extremity, or tissue 50
Including skin of vhole body
i-
Unborn child 0.5
Entire gestation period
1Annual effective dose equivalent
The DOE derived air concentrations (DACs) for airborne
radionuclides address protection of workers from airborne
radioactive contaminants. The DACs are based on limiting either
the committed effective dose equivalent to 5 rem/yr, or the dose
equivalent to any organ to 50 rem/yr/ whichever is more
restrictive. If airborne concentrations are likely to approach or
exceed DACs/ respiratory protective equipment is required. The
DACs are provided in Attachment 1 to DOE Order 5480.11.
wsqbwrod.qrd/jaj 56
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8 DESCRIPTION OF ALTERNATIVES
Following an analysis of potentially applicable response
technologies that might satisfy the remedial action goals for the
operable unit, five alternatives were developed for further
consideration. In addition, a no-action alternative was included
to provide the baseline for a comparative evaluation. Hence, six
preliminary remedial alternatives have been evaluated. These
alternatives are as follows.
8.1 ALTERNATIVE 1: NO ACTION
The no-action alternative is included as a baseline for
comparison with the other alternatives. As part of this baseline
condition, no further action would be taken at the quarry, i.e.,
the bulk wastes would remain in their current condition but the
quarry water treatment plant, selected as a removal action under
the preceding EE/CA, would be in operation. Institutional controls
currently in effect at the quarry, including fences and locked
gates, monitoring, and site ownership, would remain in place.
f
8.2 ALTERNATIVE 2: SURFACE CONTAINMENT
Under Alternative 2, all surface vegetation would be removed
and a surface containment layer, such as a soil cap or synthetic
geotextile fabric, would be installed over the entire area of the
quarry. Surface containment would reduce the release of
contaminants via surface pathways (e.g., wind dispersal) and could
limit percolation of precipitation or snowmelt through contaminated
materials in the bulk wastes. This would reduce contaminant
migration into the groundwater. However, since the bulk wastes
would remain in contact with the groundwater, contaminant migration
resulting from lateral flow of groundwater through the bulk wastes
* *
would not be reduced.
w*qbwrad.qrd/j«i .57
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8.3 ALTERNATIVE 3: SURFACE AND SUBSURFACE CONTAINMENT
Under Alternative 3, the quarry bulk wastes would be isolated
in place by installing a surface layer, as in Alternative 2, in
conjunction with placement of a natural or polymeric grouting
material around the periphery of the quarry and beneath the entire
area at a depth greater than that of the buried wastes. The
components of Alternative 3 are the same as those of Alternative 2,
i.e., surface preparation and installation of a surface containment
layer, with the addition of subsurface containment. The
containment system for Alternative 3 would consist of an underlying
confinement layer and lateral cutoff walls installed around the
periphery of the bulk wastes, in addition to the surface cover or
cap. A continuous surface and subsurface containment system would
minimize contaminant migration resulting from lateral migration of
groundwater through the bulk wastes. It would also reduce surface
releases of contaminants and contaminant migration due to
percolation of precipitation and snowmelt through the bulk wastes.
The subsurface containment system could be installed by drilling
through the wastes and injecting a confining layer around and
beneath the entire quarry.
8.4 ALTERNATIVE 4: IN SITU TREATMENT
Under Alternative 4, the contaminated materials would be
solidified in situ by mixing them with a cementitious material to
form a solid mass or by vitrifying them with an electrical current
to form a glass-like matrix. The resultant waste would limit
surface releases, percolation, and lateral and downward migration
of contaminants. The effectiveness of in situ treatment cannot be
guaranteed due to uncertainties associated with verifying treatment
success and ensuring the integrity of the solidified waste over
time. If cementation were used, complete mixing and stabilization
•
would be difficult to ensure because the bulk wastes extend over a
significant area and depth and include process equipment and other
MQbwrod.qrd/jaj 58
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unwieldy debris. In situ vitrification is generally feasible only
if the wastes contain less than 5% metal by weight and if less than
90% of the linear separation between electrodes is occupied by
metal. In situ vitrification is infeasible because of the metal
debris/ e.g., drums, process equipment, and building rubble,
scattered throughout the quarry.
8.5 ALTERNATIVE 5: EXPEDITED EXCAVATION WITH TEMPORARY STORAGE
AT THE CHEMICAL PLANT AREA
Under Alternative 5, the bulk wastes would be excavated from
the quarry and transported along a dedicated haul road to the
chemical plant area. There, they would be unloaded and temporarily
stored in an engineered facility pending a final decision on
disposal of all wastes generated by remediating the Weldon Spring
site. Transportation activities and construction and maintenance
of the temporary storage facility would be carried out in a manner
that would minimize potential releases of contaminants to the
environment. Limited treatment would be conducted, as appropriate,
to facilitate implementation (e.g., post-excavation dewatering to
facilitate waste transport and storage controL). Subsequent
treatment and/or disposal would be addressed in conjunction with
other on-site materials after completion of the RI/FS-EIS process
and approval of the record of decision for remediation of the
chemical plant area.
A variation of this alternative was considered at the
preliminary analysis stage, i.e., excavation and replacement of the
bulk wastes back into the quarry for temporary storage after
chemical sealant or a liner had been placed in the quarry.
However, technical difficulties associated with cover and seal
emplacement would compromise the effectiveness of this option, and
protection of human health and . the environment could not be
ensured. In addition, the availability of land at the quarry for
staging is extremely limited due to constraints imposed by
wtqbwrod.qrd/j< j 5 9
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ownership and topography. Therefore, storage of the required
volume of material pending preparation of the quarry for waste
emplacement would be infeasible. Thus, this variation was not
considered further.
8.6 ALTERNATIVE 6: DELATED ACTION PENDING THE RECORD OF DECISION
FOR THE SITE
Under Alternative 6, no response action would be taken with
respect to the quarry bulk wastes until the remedy is selected for
the entire Weidon Spring site. Thus, the bulk wastes would remain
in their current condition for the short term.
8.7 EVALUATION OF PRELIMINARY ALTERNATIVES
Migration control at the quarry (via containment) is the
primary emphasis of Alternatives 2 and 3, whereas source control
(via excavation and/or treatment) is the primary emphasis of
Alternatives 4 and 5. Alternative 6 (delayed action) is
essentially the same as Alternative 1 (no action) in the short
term. For purposes of evaluating alternatives, Alternative 6 is
expected to be similar to one of the action alternatives (i.e.,
Alternatives 2 through 5) in the long term. However, this would
depend upon the action selected following the delay.
Each of the action alternatives would require various support
activities prior to implementation. These activities include (1)
design and construction of staging and support areas, (2)
procurement of appropriate equipment, and (3) development of
planning and operational controls to minimize contaminant releases.
In addition, the institutional controls that now exist at the
quarry, i.e., DOE ownership, fences and locked gates, and
monitoring, are implicitly included as support activities for the
•
alternatives, as appropriate. Under the action alternatives, these
controls would be upgraded as needed. For example, certain
Mqtawred.qrd/jij 60
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portions of the fence and gates would be repaired, additional signs
would be posted, and monitoring would increase.
These preliminary alternatives were screened in the FS
according to the three screening criteria provided in the NCP:
effectiveness, implementability, and cost. Effectiveness is
defined as the ability of an alternative to protect human health
and the environment in both the short term and the long term. The
reduction of contaminant toxicity, mobility, or volume is
considered a measure of effectiveness. Implementability is defined
as the technical feasibility, resource availability, and
administrative feasibility (i.e., acceptability) of an alternative.
Costs can be considered on a relative basis at the screening stage
but cannot be the sole reason for eliminating an alternative from
consideration.
Results of the screening of preliminary alternatives are
presented in Table 7. Based on this screening, three final
alternatives were identified for managing the quarry bulk wastes:
o Alternative 1: No action.
o Alternative 5: Expedited excavation with temporary
storage at the chemical plant area.
o Alternative 6: Delayed action pending the record
of decision for the site.
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TABLE 8 Screening of Preliminary Alternative*
Alternative
Effectiveness
Implementabllity
Cost
Alternative 1:
No action
Continued Migration of contaminant* fro* the
bulk waste* could Increase exposures of human,
animal, and plant populatloni to chemicals and
radionuclIdes over tine. Contaminant toxicity.
Mobility, and volume would not be reduced.
Not applicable.
Not applicable.
Alternative 2:
Surface containment
Exposure* could be reduced In the short term
but are not expected to be effectively reduced
over the long terai due to the potential for
subsurface migration. Contaminant mobility
would be somewhat reduced, but toxicity and
volume Mould not be reduced.
Very difficult due to the
topography and extent of
the contaminated area.
Lower than other action alternatives In
the short term but expected to be higher
than those alternatives over time due to
monitoring and maintenance and
questionable effectiveness (I.e., the
eventual need for a more effective
response), which would increase costs due
to inflation and the potential Increased
extent of contamination.
Alternative 3:
Surface and
subsurface
containment
•eduction of potential exposures could be
greater than for Alternative 2 in the short
term, but effectiveness over the long term Is
doubtful due to difficulties in ensuring and
maintaining containment in a fractured setting.
Essentially infeasible due
to difficulties associated
with surface containment
(as In Alternative 2) and
with subsurface containment
due to the extent of the
affected area, depth and
type of waste material, and
fractured nature of the
bedrock.
Significantly greater than Alternatives 2
and 5 due to serious difficulties
associated with attempting to drill and
grout under existing waste conditions,
the fractured subsurface, and
questionable effectiveness.
Alternative 4:
In situ treats*
Hore protective than Alternatives 1. 2, or 3,
but effectiveness over the long term is
questionable due to uncertainties associated
with verifying treatment success and ensuring
the Integrity of the solidified waste form over
time. Contaminant mobility would be reduced.
but not toxicity; the volume might increase or
decrease depending on the treatment me jhod.
Essentially infeasible due
to the nature and extent of
the bulk wastes.
Significantly greater than Alternatives 2
and 5 could be greater than Alternative 3
due to the type and placement of the
wastes, the extensive resource
requirements, the need to control
moisture content, and questionable
effectiveness.
Alternative 3:
Expedited excavation
with temporary
storage
More protective of all the alternatives;
Initiates • permanent solution at the quarry
and supports follow-on comprehensive quarry
remediation end waste management decisions for
the entire project. Contaminant mobility would
be reduced, but not toxicity; the total volume
of material* would Increase because some
uncontaminated materials would be included.
Relatively straightforward,
using standard equipment
and procedures.
Low relative to other alternatives that
would be equally or less effective; costs
of monitoring and maintenance at the
quarry would decrease over time; total
project cost* could be minimized due to
the coordination of decisions for waste
dtspoilt ion.
wsqbwrod.qrd/JaJ
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Alternative
Effectiveness
lapleaMfntability
Cost
Alternative 6:
Delayed action
Stullar to Alternative 1 in the short ter» and
exacted to be similar to one of the action
alternatives In the long ter« (I.e.. If a
tiaiilar response was selected following the
delay).
Not applicable during the
short terai and expected to
be similar to one of the
action alternatives In the
long ter«.
Expected to be higher than certain action
alternatives In the long ter« due to the
costs associated with annltorlng until
action is eventually taken and due to
Inflation and the potential Increased
scope of the cleanup effort as a result
of contaminant •ipration.
wsqbwrod. qrd/)a J
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9 SUMMARY OF COMPARATIVE ANALYSIS OF FINAL ALTERNATIVES
9.1 EVALUATION OF THE FINAL ALTERNATIVES
The final alternatives for managing the quarry bulk wastes
were evaluated according to the nine criteria provided in the NCP
for final remedial actions, as appropriate to this interim action.
These evaluation criteria are:
o Threshold criteria — Overall protection of human
health and the environment and compliance with
applicable or relevant and appropriate
requirements.
o Primary balancing criteria -- Long-term
effectiveness and permanence; reduction of
toxicity, mobility, and volume through
treatment; short-term effectiveness;
implementability; and cost.
?>
o Modifying criteria — State acceptance and community
acceptance.
9.1.1 No Action
d..+
Consist' with EPA guidance, the no-action alternative was
carried through the detailed evaluation phase of the remedial
action decision making process to provide a baseline for comparison
with the remaining final alternatives. The no-action alternative
would not be protective of human health and the environment.
Contaminant toxicity, mobility, and volume would not be reduced.
The no-action alternative would not be effective in either the
short term or the long term. Radon releases from the uncontrolled
wastes, which have exceeded regulatory limits, would continue at
present levels as would releases of other materials. The no-action
w*qbwrod.qrd/j«j 64
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alternative would not provide a permanent remedial action solution
at the quarry.
Timeliness, engineering controls, construction and operational
factors, waste handling and implementation requirements, and costs
do not apply to the no-action alternative.
9.1.2 Expedited Excavation with Temporary Storage at the
Under the expedited excavation and temporary storage
alternative, the bulk wastes would be excavated from the quarry
with standard equipment and practices, then transported along a
dedicated haul road to the chemical plant area of the Weldon Spring
site. There, the wastes would be unloaded and temporarily stored
in an engineered facility pending a final decision on disposal of
all wastes generated by remediating the Weldon Spring site. The
storage facility would be constructed and maintained in a manner
that would minimize potential releases. Limited treatment may be
conducted as appropriate to facilitate implementation (e.g.,
dewatering could be used after excavation to facilitate waste
transport and storage). This alternative would expedite cleanup
without adversely affecting ultimate waste management decisions for
the Weldon Spring site or limiting the choice of reasonable
alternatives. Subsequent treatment and/or disposal of the bulk
wastes would be addressed in conjunction with other on- site
materials in the RI/FS-EIS that is being prepared for remediation
of the chemical plant area.
The total volume of materials that would be handled if this
alternative were implemented is estimated to be about 110,000 m3
(140,000 yd3). This volume includes materials resulting from
preparatory clearing and grubbing activities at the qnarry, the
excavated bulk wastes, uncontaminated materials excavated along
with the wastes, expansion of excavated materials following their
v»qbwrod.qrd/jaj 65
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removal from the quarry, and a 15% contingency factor. An
estimated 15 months would be required to implement this alternative
at a cost of about $11 million. These figures, however, are
preliminary and may increase as engineering design is completed.
Institutional controls would consist of continued site ownership,
monitoring, and improvement and extension of existing physical
barriers as needed (e.g., for the haul road and quarry support
area). Engineering controls would be implemented to minimize
potential releases of contaminants (e.g., radon and fugitive dusts)
in order to ensure protection of the workers, the public, and the
environment during the action period. These controls include
limiting the extent of the work area and wetting and/or covering
exposed surfaces at the quarry; controlling the speed of transport
vehicles on the haul road; and utilizing liners, run-on/runoff
control systems, and covers for the temporary storage facility at
the chemical plant area.
The expedited-action alternative would be timely and would
support overall protection of human health and the environment at
the quarry in both the short term and the long term. This
alternative would (1) reduce contaminant toxicity, mobility, and
volume through source control; (2) reduce contaminant mobility of
the excavated wastes by placing them in controlled storage in the
chemical plant area; and (3) facilitate subsequent response
activities at the Weldon Spring site, including follow-on quarry
remediation, waste characterization, and comprehensive waste
management decisions. Hence, this alternative is consistent with,
and would contribute to, a permanent solution at the quarry and the
efficient performance of overall remedial actions being planned for
the site. Furthermore, it could be implemented with readily
available equipment and standard engineering procedures. It would
also be cost effective because it would limit both inflationary
effects and potential increased cleat p efforts that would result
» *
if contamination at the quarry spread • before a response was
implemented.
w*qbwrod.qrd/jij 66
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9.1.3 Delayed Action Pending the Record of Decision for the
Site
Under this alternative, no action would be taken for the
quarry bulk wastes until a decision was made regarding the ultimate
disposition of the entire Weldon Spring site. Rather than being
expedited, remedial action at the quarry would be postponed until
the site record of decision was approved. This approval would
follow issuance of the RI/FS-EIS currently being prepared. Hence,
this alternative is similar to the no-action alternative in the
short term. The delay period is expected to last two to five
years.
In the longer term, when the response was implemented
following the delay period, many of the considerations for this
alternative could be similar to those for the expedited-action
alternative, i.e., if an excavation alternative were eventually
selected pursuant to the record of decision. That is, waste
handling and implementation requirements and engineering and
institutional controls would be similar to those for the expedited-
excavation alternative. Delaying initiation of a response action
would result in continued migration of contamination from the
quarry, and this could adversely impact human health and the
environment. The cost of implementing this alternative is expected
to increase because of inflation; the total cost of comprehensive
quarry remediation could increase even further if the extent of
contamination and the resultant scope of required cleanup increased
as a result of the delay.
w*qbwrod.qrd/jBJ 67
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9.2 COMPARISON TO THE NINE EVALUATION CRITERIA
9.2.1 Threshold Criteria
9.2.1.1 Overall Protection of Human Health and the Environment.
Of the three final alternatives, the expedited-action
alternative would provide the greatest short-term level of
protection of human health and the environment. It would control
the primary source of ongoing contaminant releases via air and
groundwater and maintain the wastes in controlled storage at a
facility engineered to prevent contaminant releases to the
environment. The no-action alternative would not be protective of
human health and the environment in either the short term or long
term since releases would continue unmitigated. While the delayed-
action alternative would not provide such protection in the short
term, it is expected that at such time as the final quarry remedial
action decision is made, a remedy providing a similar level of
long-term protection would be selected.
9.2.1.2 Compliance with ARARs.
The only identified requirement that is currently not being
met and is applicable to the no-action and delayed-action
alternatives is the State requirement of 1 pCi/1 outside a
controlled area. Since radon-222 levels currently exceed this
limit at the quarry fence line, these alternatives would not comply
with this requirement. While the expedited-response action could
not meet this requirement during implementation, the requirement
could be achieved upon completion of the remedial action both at
the quarry and at the temporary storage area.
RCRA Subtitle C requirement.? for closure of a landfill are
also considered relevant and appropriate requirements for the no-
action alternative, but the alternative would not meet this
w*qtMrod.qrd/j*j 68
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requirement. Since the expedited-action alternative is not
considered the final remedial action for the quarry/ landfill
closure requirements are not considered to be relevant and
appropriate. Even if RCRA closure requirements were considered
relevant and appropriate to excavation at the quarry, they could
properly be waived pursuant to Section 12l(d)(4)(A). This is
because the quarry bulk waste remedial action is only part of a
total remedial action which will attain that standard upon
completion. The applicability and relevance and appropriateness of
the closure requirements to the delayed-action alternative would be
determined at. the time the final remedy selection decision is made.
The expedited-response action can be conducted in compliance
with other Federal and State ARARs.
9.3 PRIMARY BALANCING CRITERIA
9.3.1 Long-term Effectiveness and Permanence
«
The expedited-action and delayed-action alternatives provide
similar levels of long-term effectiveness and permanence. The
no-action alternative would not be effective over the long term and
would not provide a permanent remedy for the quarry.
9.3.2 Reduction of Toxicity. Mobility, and Volume through
Treatment
The no-action alternative would not reduce the toxicity,
mobility, or volume of the wastes through treatment. The
expedited-action and delayed-action alternatives are expected to
provide a comparable degree of reduction in waste mobility by
removing the bulk wastes to a separate area of the site where
storage could be controlled. However, the reduction in waste
mobility would not be timely in the delayed-action alternative
because of the delay period. The wastes would be subsequently
wtqbwrod.qrd/jej 69
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treated and/or disposed of pursuant to the decisions made in the
RI/PS-EIS currently being developed for the Weldon Spring site.
Neither alternative would reduce the toxicity or volume of the bulk
wastes.
9.3.3 Short-Term Effectiveness
The expedited-action alternative would provide a timely
response to ongoing releases of contaminants to the environment.
The no-action and delayed-action alternatives would not be
effective in the short term.
9.3.4 Implement**hj? ^*"Y
The expedited-action and delayed-action alternatives are both
technically and administratively feasible. Implementability does
not apply to the no-action alternative.
9.3.5 Cost
The expedited-action alternative is estimated to cost about
$11 million. The cost of implementing the delayed-action
alternative cannot be estimated at this time. However, assuming
the delayed action is similar to the proposed expedited action,
costs would be somewhat higher because of inflation. Furthermore,
the total cost of comprehensive quarry remediation could increase
even further if the extent of contamination and the resultant scope
of required cleanup efforts increased as a result of the delay.
The no-action alternative has no cost.
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9.4 MODIFYING CRITERIA
9.4.1 State Acceptance
The State of Missouri supports the selected alternative.
9.4-2 Community Acceptance
A public comment period was held from March 5, 1990, through
April 9, 1990. In addition, a public meeting was held on Max*ch 29,
1990, to explain the preferred remedy and elicit comments from the
public. Public comments received during the comment period
indicate that the majority of the community directly impacted by
this action (i.e., residents of St. Charles County) support the
expedited-action alternative. With the exception of members of the
Coalition for the Environment, citizens in neighboring counties
provided no comments on the proposed action. Members of the
Coalition for the Environment, who reside in St. Louis County,
oppose the expedited-action alternative citing a lack of
characterization data and engineering detail in the RI/FS and
supporting documents. This organization stated that more
information is needed before one of the alternatives is selected.
No group or individual supported any of the rejected alternatives.
Responses to the comments received during the public comment period
are included in the responsiveness summary, which was prepared as
a separate document. A summary of the major issues raised during
the public comment period is included in this record of decision.
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10 SELECTED REMEDY
Based on an evaluation of the final alternatives for managing
the quarry bulk wastes, expedited action has been selected as the
remedy. Under this alternative, the bulk wastes will be excavated
from the quarry, transported along a dedicated haul road, and
placed in controlled storage in the chemical plant area pending a
final decision on disposal of all wastes generated by remediating
the Weldon Spring site.
The expedited-action alternative represents the best balance
among the evaluation criteria for remedial actions. The no-action
and delayed-action alternatives would not support a permanent
solution during the short term, and they would hinder the decision
making process for, and implementation of, overall site cleanup.
Timeliness, implementability, and cost do not apply to the
no-action alternative. Although implementation of the delayed-
action alternative might be similar to that of the currently
preferred alternative during the action period, it is not
considered timely because of the delay. Delaying cleanup could
also increase the contaminant migration problem which would
negatively impact overall protectiveness and cost effectiveness.
Expedited excavation of the bulk wastes would protect human
health and the environment by (1) controlling the primary source of
ongoing contaminant releases via air and groundwater and (2)
maintaining the wastes in controlled storage at a facility
engineered to prevent contaminant releases to the environment.
Expedited excavation would also promote the effectiveness of site
cleanup by facilitating detailed characterization of (1) the quarry
subsurface to address complete follow-on remediation, and (2) the
bulk wastes to support comprehensive waste management decisions for
the project.
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11 STATUTORY DETERMINATIONS
Consistent with the statutory requirements of Section 121 of
CERCLA, as amended/ remedial actions should be selected that:
o Are protective of human health and the environment.
o Comply with ARARs.
i-
o Are cost effective.
o Utilize permanent solutions and alternative treatment
technologies to the maximum extent practicable.
o Satisfy the preference for treatment which, as a
principle element, reduces toxicity, mobility, and
volume.
The quarry bulk waste remedial action is only one of several
actions that will be taken to remediate the Weldon Spring site (see
Figure 5). The manner in which this focused action satisfies these
five requirements is discussed in the following subsections.
11.1 PROTECTION OF HUMAN HEATH AND THE ENVIRONMENT
The selected remedy is protective of human health and the
environment by (1) controlling the primary source of ongoing
contaminant releases from the quarry via air and groundwater and
(2) maintaining the wastes in controlled storage at a facility
engineered to prevent release of contaminants to the environment.
Although the quarry bulk wastes do not pose a significant risk to
human health and the environment in the short term, the continued
presence of the bulk wastes could pose significant threats in the
future.
vcqbwrod.qrd/j*j '3
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The bulk wastes contain elevated concentrations of both
radioactive and chemical contaminants, and the limestone underlying
the quarry contains fractures and fissures that constitute
potential pathways for contaminant migration. Contaminants are
currently migrating into the groundwater beneath the quarry, and
radon gas concentrations and gamma exposure rates within the quarry
and at the fence line are elevated above background levels.
In addition, some types of vegetation in the vicinity contain
elevated levels of radioactivity. This contamination does not pose
an immediate risk because site access is controlled/ the nearby
environment is continuously monitored, and corrective actions to
protect human health and the environment would be implemented if
warranted. However, if administrative control of the quarry were
lost at some point in the future, exposure to the bulk wastes could
potentially result in excessive health risks to persons frequently
entering it.
Procedures to protect human health and the environment will be
implemented during the quarry bulk waste remedial action. The
environmental pathway of most concern is atmospheric releases.
Extensive control measures will be implemented during all phases of
the action that could create airborne emissions. During excavation
of the wastes, emissions will be controlled by water sprays, foams,
and tarpaulins, as needed. The wastes will be transported to the
chemical plant area in trucks along a dedicated haul road. Current
plans are to package the wastes in containers to ensure minimal
releases. Dust control measures similar to those at the quarry
will be used while the wastes are being unloaded at the temporary
storage area. Finally, all wastes susceptible to windblown erosion
or release of radon gas will be covered as soon as practical
following placement in the temporary storage area. These measures
will ensure minimal atmospheric releases as a result of
implementing this action and thus be protective of human health and
the environment.
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The selected remedy further protects human health and the
environment in that it supports overall remediation of the Weldon
Spring site by facilitating further investigations at the quarry
area. These investigations are essential for evaluating the
various response action alternatives for the quarry. An
understanding of the nature and extent of fracture joints and
fissures and associated soil and groundwater contamination can be
established only after the bulk wastes have been removed. Hence,
the proposed removal of bulk vastes from the quarry would
facilitate the development of a comprehensive plan to address the
issue of subsurface remediation in this area.
11.2 COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS
The selected remedy will comply with applicable or relevant
and appropriate requirements, unless those requirements have been
properly waived in accordance with CERCLA, and will be performed
consistent with all pertinent DOE Orders as set forth below. The
ARARs are presented below according to location-specific, action-
specific, and contaminant-specific requirements. The excavation,
transportation, and storage of the wastes are considered to be on-
site actions and need only comply with the substantive requirements
of Federal and State environmental laws that are ARARs.
11.2.1 Location-Specific ARARs
The analysis of location-specific ARARs included a review of
the Resource Conservation and Recovery Act, the Missouri Hazardous
Waste Management Laws, the National Historical Preservation Act,
the Archeological and Historic Preservation Act, the Archeological
Protection Act, the Endangered Species Act, the Fish and Wildlife
Coordination Act, the Clean Water Act, the Wilderness Act, the
Wildlife Management Act, the Coastal Barrier Resources Act, the
wsqbwrod.qrd/jaj 75
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Clean Air Act, and the Surface Mining Control and Reclamation Act
as outlined in the CERCLA Compliance with Other Laws Manual.
The planned installation of a 10-cm (4-in) pipe to connect the
quarry with an existing county water main (for decontamination,
fire-fighting capability, and other water requirements) could
impact cultural resources. Requirements associated with protection
of cultural resources are applicable (i.e., National Historic
Preservation Act, Archeological -and Historic Preservation Act, and
Archeological Resources Protection Act). Construction of the water
line will be coordinated with the Missouri State Historic
Preservation Officer to ensure compliance with these requirements.
The proposed action will not impact floodplains, wetlands, or
sensitive ecosystems.
No other location-specific requirements were found to be
either applicable or relevant and appropriate to the proposed
action.
11.2.2 Action-Specific ARARs
The analysis of action-specific ARARs addressed the following
tasks for the quarry bulk waste remedial action:
o Excavation - removal of bulk wastes from the
quarry.
o Storage - temporary storage in a waste management
unit defined as a waste pile which includes surface
impoundments for runoff control.
Presented below is a discussion of the ARARs for these
*
activities.
wtqbwrod. qrd/j a j 76
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Excavation
Requirements associated with the excavation of wastes are
found in RCRA closure requirements. A,complete analysis of closure
requirements for the quarry is not within the scope of the quarry
bulk waste remedial action since the action will be complete with
excavation of the bulk wastes. The follow-on residual RI/FS will
characterize the nature and extent of any contamination left in the
cracks and fissures of the rock, develop risk-based cleanup
»-.
criteria, and define appropriate closure requirements. As
discussed previously, closure requirements for the quarry are
neither applicable nor relevant and appropriate to the excavation
phase of remedial action.
Closure requirements will be considered in more detail in the
follow-on residual RI/FS. After excavation of the bulk wastes,
additional characterization work will be performed to better
characterize the nature and extent of any contamination left in the
cracks and fissures of the rock, and to define appropriate closure
requirements.
Occupational safety and health standards for workers involved
in activities at CERCLA sites are given in 29 CFR 1910.120. These
requirements are not applicable under exemptions in the Atomic
Energy Act. These requirements are, however, relevant and
appropriate to this remedial action.
Storage
RCRA Subtitle C requirements for waste piles and surface
impoundments are considered possible ARARs for the selected action.
Missouri Hazardous Waste Management requirements are similar to
Federal requirements, with some differences as discussed below.
The areas of the regulations that were evaluated include those for
waste management units defined as waste piles and surface
wtqbwrod.qrd/jij 77
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impoundments. The respective requirements are presented in
40 CFR 264 Subparts L (Waste Piles), K (Surface Impoundments), G
(Closure and Post Closure), and F (Groundwater Protection).
The RCRA design requirements for waste piles are found in
Subpart L, Section 264.251. These requirements are relevant and
appropriate to this remedial action. Therefore, the waste pile
will be designed in accordance with 40 CFR 264.251 to store the
material as if RCRA were applicable. The facility will include a
liner, a leachate collection and removal system, a run-on control
system, a runoff management system and a cover for areas which
contain particulate matter subject to wind dispersal.
The collection and holding facilities within the temporary
storage area were evaluated with respect to RCRA requirements in
Subpart K, Section 264.221 and the Missouri Hazardous Waste
Management Laws for surface impoundments. The State and Federal
RCRA requirements for surface impoundments are not legally
applicable but may be relevant and appropriate. The design
requirements for a double liner system specified in 40 CFR
264.221(c) are relevant and appropriate. However, considering the
expected duration of storage, the clay liner requirement of 10 CSR
25-7.264(2)(k) is not appropriate. The soil underlying the
proposed location for the temporary storage area is already
contaminated; the eventual remedy of the chemical plant area will
include remediation of on-site contaminated soil.
Similarly, the groundwater protection requirements of 40 CFR
264 Subpart F are not legally applicable but the groundwater
monitoring requirements are considered to be relevant and
appropriate. The groundwater response requirements, however, are
not considered to be relevant and appropriate to this remedial
wtqbwrod.qrd/jaj 78
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action/ which does not address groundwater remediation. Even if
the groundwater response requirements were found to be relevant and
appropriate, they could be waived pursuant to Section 121(d)(4)(A)
and Section 121(d)(4)(C) of CERCLA. While not a part of this
remedial action, groundwater remediation will be addressed in the
final remediation of the chemical plant area. In addition, it is
not practical to separate groundwater under the temporary storage
area from groundwater being addressed as part of the overall RI/FS-
EIS currently being prepared for remediation of the entire chemical
plant area.
Similarly, the requirements of 40 CFR 264.258, Closure and
Post-Closure Care, are not legally applicable and are not
considered to be relevant and appropriate to the quarry bulk waste
remedial action. If found to be relevant and appropriate, these
requirements could be waived under Section 121(d)(4)(A) and Section
121(d)(4)(C) of CERCLA. The closure requirements are not pertinent
since the bulk waste removal and storage is an interim action and
closure of the temporary storage area cannot adequately be
addressed until the final remedy for the chemical plant area is
selected. In addition, it is technically impractical to close the
temporary storage area until the material can be removed for final
disposition consistent with the ultimate site remedy. The
temporary storage area will not be closed with the wastes in place.
Other considerations for storage include portions of the Land
Disposal Restrictions, 40 CFR 264 Subpart E and the Toxic
Substances Control Act, 40 CFR 761.65. These requirements deal
with prohibitions on storage and may be applicable for this action.
The limitations on storage time are waived under the provisions of
Section 121(d)(4)(A) and Section 121(d)(4)(C) of CERCLA since the
schedule for final disposition of the quarry bulk wastes is
controlled by the decision making*process.for remediation of the
chemical plant area. It is not technically feasible to comply with
wcqbwrod.qrd/jaj 79
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the time limitations since a remedy for the chemical plant area
will not be selected in the required time frame.
An additional action-specific consideration is for
transportation. Requirements pertaining to transportation of
radioactive and chemically hazardous wastes are not legally
applicable to this action, but some portions are relevant and
appropriate. For purposes of this action, a simplified manifest
system will be developed. This system will include tracking waste
shipments from the quarry to the temporary storage area; placarding
the trucks; and using strong, tight containers to prevent leakage
under conditions normally incident to transportation.
11.2.3 Contaminant—Specific ARARs
The analysis of contaminant-specific ARARs was performed to
address each major environmental law or regulation pertinent to the
types of contaminants that will be encountered during this remedial
action.
NESHAP requirements for radionuclides, given in 40 CFR 61
Subparts H and Q, and asbestos given in Subpart M are legally
applicable to all phases of the action.
State standards found in 10 CSR 10-5.100 pertaining to control
of airborne particulate matter, and in 10 CSR 10-5.180 pertaining
to particulate standards for internal combustion engines are
applicable to the implementation phase and will be met.
40 CFR 192.02(b)(l) addresses releases of radon from uranium
mill tailings disposal piles. These standards will be relevant and
appropriate after the bulk wastes have been placed in controlled
storage. At that time, the temporary storage area will meet the
radon-222 flux standards specified in 40 CFR 192.02(b)(1). These
standards require reasonable assurance that radon-222 releases will
80
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not (1) exceed an average release rate of 20 pCi/m2/sec or (2)
increase the annual average concentration of radon-222 in air at or
above any location outside the site perimeter by more than 0.5
pCi/1.
Although DOE Orders are not ARARs in that they are not
promulgated standards, the radiation protection requirements given
in DOE Orders 5400.5 and 5480.11 are most suitable for this action.
The requirements in these two orders -are based on recent radiation
dosimetry models while the radiation protection requirements in
both 10 CFR -20 and 19 CSR 20 are based on out-of-date dosimetry
considerations. Hence, the action will be conducted in accordance
with these two DOE Orders for radiation protection. As discussed
in Section 7.1.6, the requirements in 10 CFR 20 are currently being
revised. The action will comply with any provisions in the revised
10 CFR 20 and subsequent revisions to 19 CSR 20 that are more
stringent than those in these two DOE Orders.
The State radon-222 limit of 1 pC/1 in uncontrolled areas
cannot be achieved during implementation of this action. This
standard is waived pursuant to Section 121(d)(4)(C) of CERCLA
during implementation. This requirement will be achieved upon
completion of the action.
Standards of control are established under the Toxic
Substances Control Act for the cleanup of PCB spills and for
asbestos exposure limits. 40 CFR 761.125 addresses cleanup
requirements for PCB spills and is applicable during transport of
the bulk wastes. Permissible exposure limits to asbestos fibers
are addressed in 40 CFR 763.121(c). The standard is relevant and
appropriate to the implementation phase of this action.
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11.3 COST EFFECTIVENESS
The selected remedy is estimated to cost about $11 million
and is expected to be implemented in 15 months. These figures,
however, are based on conceptual estimates performed early in the
RI/FS process and both are likely to increase as engineering design
is completed. This remedy is cost effective since postponing the
action could result in the continued spread of contamination in the
quarry area. This would result in the need for a more extensive
cleanup effort in the future. In addition, delaying action would
result in higher costs due to inflation. Both of these effects
will be minimized by implementing the selected remedy. In
addition, this remedy would promote the effectiveness of
remediation of the entire Weldon Spring site by facilitating
detailed characterization of (1) the quarry subsurface to address
follow-on remediation, and (2) the bulk wastes to support
comprehensive waste management decisions for the entire Weldon
Spring site.
11.4 UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT
TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICABLE
The selected remedy will result in the permanent removal of
the bulk wastes from the quarry. This will remove the source of
contaminant releases to the air and groundwater in the quarry area.
The use of alternative treatment technologies or resource recovery
technologies is beyond the scope of the quarry bulk waste remedial
action. This action will not result in a permanent solution for
either the quarry or the bulk wastes. A final decision for the
quarry area will be made following removal of the bulk wastes (this
action) and completion of detailed studies on the need to perform
additional remediation in the quarry area. Treatment and disposal
decisions for the wastes will be included in the RI/FS-EIS for
• •
remediation of the chemical plant area.
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11.5 PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT
Treatment of the bulk wastes to reduce toxicity, mobility,
and volume is beyond the scope of this action. The action is
limited to excavation of the bulk wastes from the quarry with
transport to, and temporary storage at, the chemical plant axea.
The wastes will be treated only to facilitate transportation and
storage activities (e.g., segregation, dewatering). They will be
characterized in detail after they are placed in controlled storage
\:
in the chemical plant area. The results of this detailed
characterization will be used to finalize decisions on potential
treatment strategies to reduce toxicity, mobility, and volume.
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RESPONSIVENESS SUMMARY
The remedial investigation/feasibility study (RI/FS)
documents vere issued to the general public on March 5, 1990, and
the public comment period extended through April 9, 1990. A public
meeting was held on March 29, 1990, at the Ramada Inn in
Wentzville, Missouri, as a part of the community participation
process. In addition to the public meeting, the U.S. Department of
Energy (DOE) held numerous briefings and meetings with public
officials, school administrators, special interest groups, and
members of the general public. A separate responsiveness summary
document has been prepared to address the issues raised during the
public comment period. This document lists the major issues raised
in oral and written comments on the RI/FS documents and provides
the DOE responses to these issues. In addition, individual
responses to all written comments are provided. The following
discussion, which has been extracted from the responsiveness
summary document, provides summaries of the major issues associated
with the proposed action followed by DOE responses.
The conceptual approach for -implementing the preferred
alternative, as presented in Chapter 8 of the FS report, was
revised following receipt of the public comments. The approach
currently being evaluated is to conduct basic waste sorting at the
quarry, load the sorted wastes into containers such as large steel
boxes, and transfer the containers to trucks for transport to the
chemical plant area. At the chemical plant area, the containers
will be unloaded and the wastes placed directly into controlled
storage. The empty containers will be returned to the quarry for
reuse. Such an approach could allow for the return trip to be on
the dedicated haul road eliminating all truck traffic on State
Route 94. This approach will be evaluated in detail after this
record of decision is issued.
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Issue 1
Comment. The RI/FS documents include a disclaimer in which
it is stated that the DOE does not assume any legal liability or
responsibility for the accuracy, completeness, or usefulness of the
information included in the documents. How can the DOE proceed
with this action when it does not stand behind the information
supporting its selection?
\:
Response. The disclaimer was included in these documents by
mistake. The DOE does indeed stand behind the information and
analyses provided in the RI, Baseline Risk Evaluation (BRE), and
FS. This disclaimer is used in documents summarizing work
sponsored by the DOE that is experimental or developmental in
nature. Its purpose is to exempt the DOE and its contractors from
legal liability for research activities so that new ideas and
concepts can be explored without being restricted by legal
constraints. These conditions do not apply to this RI/FS.
Issue 2
Comment. The proposed action entails temporary storage of
the bulk wastes at the chemical plant area. How long is
"temporary" storage?
Response. The quarry bulk wastes are scheduled to be in
temporary storage for three to six years.
Issue 3
Comment. How do we know that temporary storage will not
become permanent?
w*abwrod.qrd/jaj 85
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Response. The temporary storage facility will not be
designed to meet permanent disposal requirements nor is there any
consideration of ever upgrading it to meet such requirements.
Permanent disposal requires separate processes of environmental
compliance, regulatory concurrence, and public involvement. This
does not mean that construction of a permanent disposal cell on
site will not be considered in the future; however, it does mean
that temporary- storage of the bulk wastes will not influence that
disposal decision.
Issue 4
Comment. Removal of the quarry bulk wastes with temporary
storage in the chemical plant area is only an interim action in the
overall remediation of the Weldon Spring site. When will a
decision on the permanent disposal of all site wastes be reached?
Response. The DOE is currently preparing an RI/FS under the
Comprehensive Environmental Response, Compensation, and Liability
Act (CERCLA) to evaluate alternatives for the permanent disposal of
all wastes generated by remediating the Weldon Spring site. The
analyses in that RI/FS will include those required in an
environmental impact statement (EIS) for compliance with the
National Environmental Policy Act (NEPA). This integrated
CERCLA/NEPA approach is being referred to as the RI/FS-EIS process.
The RI/FS-EIS is being prepared consistent with U.S. Environmental
Protection Agency (EPA) guidance; a preliminary internal review
draft will be available in late 1990. The RI/FS-EIS documents will
be available for review by EPA Region VII, the State of Missouri,
and the general public in 1991, and a joint EPA/DOE record of
decision for this proposed action will be issued in 1992.
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Issue 5
Comment. The quarry bulk wastes should not be moved until
a permanent disposal decision has been reached for managing all
wastes from the Weldon Spring site and a disposal facility is ready
to accept the wastes. This interim remedial action is not a wise
expenditure of tax dollars.
Response. Delaying this interim remedial action vould
postpone the attainment of remedial action objectives at the quarry
(e.g., to respond to ongoing releases by removing the primary
source of contamination from the quarry and to initiate necessary
characterization activities). The preferred alternative can be
implemented in a manner that will not endanger students and staff
at Francis Howell High School or any other individuals in the area.
The extensive monitoring program currently in place will be
expanded prior to initiating the proposed action to ensure the
health and safety of nearby residents and the environment.
The DOE is currently preparing an RI/FS-EIS to evaluate
alternatives for the permanent disposal of all wastes generated by
remediating the Weldon Spring site. Although the RI/FS-EIS will be
available for public review and comment in 1991, the length of time
to implement permanent disposal options will take several more
years. Delaying the proposed removal of the bulk wastes would
result in continued uncontrolled release of contaminants to the
environment in the quarry area. The proposed action is being taken
at this time to respond to this release.
Although some additional cost will be incurred by placing
the bulk wastes in temporary storage, most of the components
associated with this action will be required whether the action is
taken now or in the future. The wastes must be removed and
characterized to permit an informed evaluation of various treatment
options prior to final disposal. Hence, the incremental cost is a
wtqbwrod.qrd/j»j 87
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good expenditure of funds based on the considerable benefits
associated with expediting the action, i.e., the proposed action
i
will protect human health and the environment and support overall
waste management decisions for the project. These and other
reasons for conducting the proposed action are discussed in greater
detail in the FS.
Issue 6
Comment. Why not simply move the well field to ensure the
safety of this source of potable water? This would be a much
simpler and cheaper solution.
Response. There is currently no need to consider moving the
well field or providing an alternative source of potable water
because the water in this well field is not contaminated. Removing
the source of potential threat to the well field is only one of the
reasons for this action. The bulk wastes must be removed in order
to perform detailed characterization of the wastes for evaluating
appropriate treatment technologies and disposal alternatives. In
addition, the wastes must be removed to allow for detailed
characterization of the quarry area. Removal of the bulk wastes is
responsive to the need to protect human health and the environment
and also serves to protect an important natural resource (i.e., the
groundwater in this area).
Issue 7
Comment. Will any wastes from other areas be brought to the
Weldon Spring site for disposal?
Response. The proposed action is limited to management of
the quarry bulk wastes. Management of all. wastes from cleanup of
the Weldon Spring site is the subject of a separate RI/FS-EIS
process that is currently under development. There are no plans to
mqbwrod.qrd/jej 88
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bring wastes from other areas to the Weldon Spring site for
disposal. The record of decision for remediation of the chemical
plant area of the Weldon Spring site will address the scope of
waste disposal and limitations on use of the Weldon Spring site for
future actions.
Issue 8
Comment. The wastes should be sorted and containerized at
the quarry prior to transport to the chemical plant area for
temporary storage.
Response. This type of issue would typically be addressed
during the engineering design phase of the project. However, the
DOE has reviewed this concept and believes it has merit. The
approach currently being evaluated is to conduct basic sorting at
the quarry, load the sorted wastes into containers such as large
steel boxes, and transfer the containers to trucks for transport to
the chemical plant area. At the chemical plant area, the
containers will be unloaded and the wastes placed directly into
controlled storage; the empty containers will be returned to the
quarry for reuse.
This approach would tend to decouple the excavation,
transportation, and unloading activities. For example, extra
containers could be loaded at the quarry during a second shift or
while wastes were being transported to the temporary storage area.
Trucks could travel along the haul road in small convoys (i.e.,
three to six trucks) to the temporary storage area where the
containers would be off-loaded. The wastes would be removed from
the containers and placed into controlled storage. Empty
containers would be loaded onto -the trucks and returned to the
quarry. Such an approach could allow for-the return trip to be on
the dedicated haul road. Plans for the haul road may need to be
Mqbwrad.qrd/j«j 89
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modified to include several turnouts which, in conjunction with
radio contact, would allow safe passage of truck traffic. This
would eliminate all truck traffic on Route 94.
Issue 9
Comment. Why is it necessary to move the wastes closer to
Francis Howell High School for temporary storage? Why not take the
quarry wastes somewhere else for disposal?
Response. No disposal facility is currently available for
the quarry wastes. Furthermore, a permanent waste disposal
decision is a very complex issue and will not be made for a few
years. Therefore, the only alternatives at this time are either to
remove the quarry bulk wastes and temporarily store them pending a
waste disposal decision or delay the quarry cleanup action. The
DOE believes it is important to initiate the quarry cleanup action
as soon as possible (see responses to Issues 5 and 6). The
question then becomes where to store these wastes.
In addition to the fact that there is simply no other
available space, there are several good reasons for temporarily
storing the wastes in the chemical plant area. On-site storage
will ensure that no individuals are inadvertently exposed because
access to the chemical plant area is controlled. Also, the
presence of on-site DOE and contractor staff will ensure continuous
oversight. The wastes can be safely and expeditiously
characterized to allow for an informed decision on their final
disposal to be made as soon as possible. Finally, the extensive
monitoring capability available in the chemical plant area can be
used to ensure the health and safety of nearby residents. This is
the best way to store these materials in the near term.
w«qbwrod.qrd/j»j 90
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Issue 10
Comment. There is insufficient engineering information on
the proposed action' to adequately assess the feasibility of its
implementation. It is not possible to select an alternative with
the level of detail provided in the RI/FS documents.
Response. The level of detail provided in the RI/FS
documents is consistent with that required by the EPA for actions
of this magnitude. Detailed engineering for this action cannot be
initiated until the record of decision has been issued. However,
the analyses' presented in the RI/FS and supporting documents
demonstrate that this action can be performed safely and in
compliance with all applicable standards and regulations. This
information is sufficient to allow for selection of an alternative.
The level of detail necessary to determine the engineering
feasibility of this action is presented in the preliminary
engineering report supporting the FS. The design documents to be
developed following issuance of the record of decision will focus
on the physical aspects of this action such as equipment needs,
operational requirements, material handling, and cost. Planning
related to dealing safely with the various types of contaminants
and hazards that may be encountered will be presented in an
operational environmental, safety, and health plan. The results of
these two planning efforts will ensure that this action is
implemented safely.
Issue 11
Comment. There is insufficient characterization data to
adequately plan this action.
•
» •
Response. Previous investigations have provided a
significant amount of information on the physical, chemical, and
wsqbwrod.qrd/j«j 91
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radiological characteristics of the wastes. The results of these
investigations, which are presented in the RI, are consistent with
the disposal history at the quarry. This information is sufficient
to design a safe plan for the removal/ transport, and temporary
storage of the bulk wastes.
It is possible that some unknown waste material was placed
in the quarry. In designing the waste removal process, an
observational approach will be used to deal with this possibility.
In this approach, planning is based on available data and realistic
assumptions concerning field conditions. Adjustments are made in
the field as work proceeds. Deviations from expected conditions
and mechanisms by which to identify their occurrence are defined,
and plans are developed to address or mitigate adverse effects that
result from these deviations. This approach ensures responsiveness
to actual field conditions.
Issue 12
Comment. The quarry bulk wastes contain residual
concentrations of trinitrotoluene (TNT), dinitrotoluene (DNT), and
their decomposition products. Is there any possibility that an
explosion could occur while the bulk wastes are being removed?
Response. The highest measured concentration of TNT in the
bulk wastes is about 2%. This value is the result of biased
sampling in which areas of surf icial discoloration were targeted in
an effort to define the maximum concentrations. The measured value
of 2% is well below the concentration that presents an explosive
hazard during excavation (which is 12% to 15%). The concentrations
of DNT and decomposition products of TNT and DNT in the bulk wastes
are much lower than the measured concentration of TNT. The
proposed action has been reviewed by Hercules, Inc., a company with
extensive expertise in dealing with explosives. Their technical
review concluded that the current plan is feasible and that an
wsqbwrod.qrd/jij 92
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explosion is highly unlikely. However, the concentration of
nitroaromatic compounds in the bulk wastes will be evaluated as the
wastes are being excavated to ensure that there are no pockets
containing much higher concentrations of TNT that could present an
explosive hazard. Plans will be in place to deal with explosive
concentrations of TNT in the unlikely event of such an occurrence.
Issue 13
Comment. Effective radon and dust control measures should
be used to minimize atmospheric releases while implementing this
action.
Response. Extensive radon and dust control measures will be
implemented during all phases of this action that have a potential
for creating airborne emissions. During excavation of the wastes,
emissions will be controlled by water sprays, foams, and
tarpaulins, as needed. The wastes will be transported to the
chemical plant area in trucks along a dedicated haul road. Current
plans are to package the wastes in containers to ensure minimal
releases. Dust control measures similar to those at the quarry
will be used while unloading the bulk wastes at the temporary
storage area. Finally, all wastes susceptible to windblown erosion
or release of radon gas will be covered as soon as practical
following placement in the temporary storage area. These measures
will ensure minimal releases of radon gas or contaminated dust as
a result of implementing this action.
Issue 14
Comment. It is essential that remedial actions at the
Wei don Spring site be implemented in a manner that will not
compromise the health and safety of the people of St. Charles
• •
County. A thorough environmental monitoring program should be put
in place prior to initiating this action to ensure the health and
wsqbwrod.qrd/jej 93
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safety of nearby residents and students and staff at Francis Howell
High School.
Response. An extensive environmental monitoring program is
currently in place at both the quarry and chemical plant areas.
This program provides extensive information on the current status
of these two areas. The monitoring program will be expanded at
both areas before the bulk waste remedial action is initiated. An
operational environmental, safety, and health plan is currently
being prepared to address the specific needs of this action. An
array of air monitors will be placed at the temporary storage area
and site perimeter to detect any airborne contamination that could
impact Francis Howell High School. The health and safety of nearby
individuals will not be compromised by this action.
Issue 15
Comment. An emergency response plan should be developed
before this action is initiated to address actions that would be
taken if there are any spills or natural disasters. This plan
should address earthquakes, high winds, tornadoes, spills, and any
other events that could cause large releases of radioactive and
chemical contaminants to the environment. The Francis Howell
School District should be part of the planning process because of
the close proximity of its elementary and high schools.
Response. The DOE will develop an emergency response plan
to address credible emergency situations consistent with the
hazards posed by the proposed action. This plan will identify
measures to be taken in the event of a spill, transportation
accident, or natural disaster. In developing this plan, the DOE
will involve the Francis Howell School District and local officials
who would require notification or•coordination in the event of an
•
emergency. Removal of the bulk wastes will not begin until an
emergency response plan is in place.
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Issue 16
Comment. The ongoing environmental monitoring program at
the quarry needs to continue without interruption before, during,
and after removal of the bulk wastes. This is the only way to
ensure the safety of the St. Charles County well field.
Response. The St. Charles County well field is being
extensively monitored by Federal, State, and local authorities.
This monitoring indicates that the well field has not been impacted
by contaminants migrating from the quarry. The DOE will increase
its monitoring efforts during the bulk waste remedial action to
ensure that this action does not result in contamination impacting
the well field. Monitoring of the well field will continue
following removal of the bulk wastes while studies are undertaken
to evaluate the need for additional remediation of this area.
Monitoring activities at the quarry will not be discontinued until
all follow-on studies have been completed and any additional
remedial actions have been implemented. Such future decisions will
rely on input from EPA Region VII, the State of Missouri, and
officials from St. Charles County.
Issue 17
Comment. Since the levels of radon are elevated at the
quarry, why move these materials closer to Francis Howell High
School and increase the risk to students from radiation exposure?
Response. The bulk wastes are being removed in part to
control radon emissions from these materials. The radium-
contaminated soils will be placed in controlled storage in the
temporary storage area and covered with a liner that is very
effective at reducing radon ga£ releases. Modeling studies
described in the FS indicate that the radon concentrations at
Francis Howell High School resulting from this action would be
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indistinguishable from background levels. The DOE will monitor for
radon-220, radon-222, and their short-lived decay products at the
temporary storage area, the site perimeter, and Francis Howell High
School during implementation of the action and during the temporary
storage period. This monitoring program will allow for upgrading
of radon emission controls, if necessary, to prevent impacts to the
high school.
Issue 18
Comment. Results of environmental monitoring activities
need to be provided to the general public in a timely manner. The
results of 1988 environmental monitoring activities were not issued
until January 1990. The general public needs to be kept better
informed, especially as the bulk waste remedial action proceeds.
Response. The 1988 environmental monitoring report was
issued late due to the internal review process within the DOE. The
1989 environmental monitoring report will be issued in the near
future. The DOE agrees on the need to provide environmental
monitoring results in a timely manner and is currently developing
a plan to issue the results of environmental monitoring on a more
frequent basis. Any anomalous environmental monitoring data
associated with the bulk waste remedial action will be made
available to local authorities and any potentially affected
individuals as soon as possible.
Issue 19
Comment. The report recently released by the Committee on
the Biological Effects of Ionizing Radiations (i.e., the BEIR V
report) indicates that the biological effects of exposure to low
levels of radiation are greater .than previously estimated. Are
there likely to be any changes in Federal limits on permissible
levels of radiation exposure to workers or the general public as a
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result of this study? What impact do these results have on the
proposed action?
Response. The recently issued BEIR V study includes a
detailed description of current data on the health risks of
exposure to low levels of ionizing radiation. This study estimates
that the health risk is about three times greater than estimated in
the previously issued BEIR III report. However, it should be noted
that the data used to reach these conclusions have limitations, as
noted in the BEIR V study. Assessment of the carcinogenic risks
that may be associated with low doses of radiation were
extrapolated• from effects observed at doses larger than 10 rem
delivered over a short period of time. In addition, it was
necessary to use assumptions about the relevant dose-effect
relationships and the underlying mechanisms of carcinogenesis.
Health hazards associated with chronic exposure to low
levels of ionizing radiation have been studied in areas such as
those having high levels of background radiation, areas receiving
fallout from nuclear weapons testing, and areas near nuclear
installations. The data from these studies do not indicate an
elevated level of cancer risk. Hence, it is still not possible to
draw definitive conclusions of the cancer risks associated with
chronic exposure to low levels of ionizing radiation.
The permissible level of radiation exposure for workers is
based on limiting their health risk to levels that are comparable
to the occupational risks from other industries that are considered
to be safe. The permissible level (5 rem/yr) may be reduced as a
result of recent studies that indicate that the risk from exposure
to low levels of ionizing radiation is higher than previous
estimates. The DOE and other Federal agencies are currently
examining this issue. The radiation doses to workers who would
implement this action would be considerably below current limits.
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The results of the BEIR V study are not expected to result
in significant changes in the permissible levels of radiation
exposure to the general public or in DOE concentration limits for
radionuclides in liquid or gaseous effluents. The risk factors
presented in the BEIR V report are consistent with those used by
the EPA in developing revisions to the National Emission Standards
for Hazardous Air Pollutants under Section 112 of the Clean Air Act
for radionuclides and the U.S. Nuclear Regulatory Commission (NRC)
in developing revisions to it CFR 20 for permissible levels
of radionuclides in air and water in controlled and uncontrolled
areas. The DOE standards are consistent with those developed by
the EPA and NRC.
A major element of the DOE radiation protection program for
occupational and public exposures is the as low as reasonably
achievable (ALARA) concept. Under the ALARA process, all exposures
to radiation and all releases of radioactivity to the environment
must be reduced to levels that are as low as reasonably achievable.
The DOE is committed to this approach. The proposed action would
not be impacted even if more stringent standards were in effect
because the predicted levels of radiation exposure to workers and
the public are well below applicable standards.
Issue 20
Comment. Transporting the wastes by truck from the quarry
to the chemical plant area has the potential for spreading
contamination to currently clean areas. How will this possible
spread of contamination be controlled?
#
Response. The wastes will be transported to the chemical
plant area in trucks that will travel at low speeds along a
dedicated haul road. Current plans are to package the wastes in
containers to ensure minimal releases during transport. The
exteriors of the trucks will be surveyed for contamination before
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leaving the quarry and chemical plant area, and any loose
contamination will be removed before the trucks are allowed to exit
either area. Finally, periodic surveys of the haul road will be
performed to ensure that contamination controls are effective. If
any contamination is detected on the haul road, the area will be
cleaned up immediately and measures will be taken to prevent a
reoccurrence. This approach will ensure that contamination is not
being spread to the environment as a result of waste relocation.
Issue 21
Comment. .As currently planned, trucks leaving the quarry
would cross State Route 94 near the quarry and then proceed along
a dedicated haul road to the chemical plant area. Empty trucks
would return to the quarry using Route 94. The DOE should
investigate further the use of grade separation (i.e., an
underpass) at the intersection of State Route 94 and the haul road
to avoid any crossing of Route 94 by trucks. In addition, plans
should be developed to minimize or eliminate truck traffic on
Route 94 during time periods that bus or student traffic are on
this roadway.
Response. The DOE agrees that transportation safety is one
of the most significant issues associated with this action. As
presented in the FS, wastes would be loaded directly into trucks.
In this approach, the rate of waste removal could be limited by the
time required for a truck to travel to the temporary storage area
and return to the quarry for another load. By staging the
containers at the quarry, and using the trucks only to shuttle
containers back and forth to the temporary storage area, the entire
operation can sustain the extra time required for trucks to share
the single lane haul road. To provide further flexibility, plans
for the haul road could be modified to include turnouts which, in
• •
conjunction with radio contact, would allow safe passage of truck
traffic. This would eliminate all truck traffic on Route 94.
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In addition, discussions are currently taking place with the
State of Missouri on the use of grade separation where the
dedicated haul road crosses State Route 94. This would eliminate
all crossing of Route 94 by trucks. Use of grade separation would
require reconstruction of a section of Route 94. The decision on
use of this option will be largely dictated by the cost of the
reconstruction relative to that associated with other safety
measures that could be used at this crossing (e.g., flagmen,
traffic signals). The DOE will continue working with the State to
resolve this issue.
Issue 22
Comment. Will this action have any impact on wildlife in
the immediate area?
Response. Activities related to this action will destroy
about 15 ha (37 acres) of vegetation at the quarry, along the haul
road, and at the chemical plant area. Some small, relatively
immobile wildlife will be lost, and other more mobile wildlife will
be disturbed, displaced, and possibly lost during construction and
operation. However, the overall impact will be very minor given
the extensive amount of wildlife habitat in the surrounding area.
«•
Issue 23
Comment. There has been a higher incidence of childhood
leukemia in St. Charles County than that expected in the general
population. It is imperative that this action be conducted-in a
manner to ensure that no additional cancers will result from
removing the bulk wastes from the quarry and transporting them to
the chemical plant area for temporary storage.
•
Response. The Missouri Department•of Health retrospective
childhood leukemia study does not support the contention that there
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are elevated levels of childhood leukemia in St. Charles County.
The study indicates an increased level of childhood leukemia cases
during the period of 1975 through 1979, but the incidence rate over
the entire period of the study (i.e., 1970 through 1983) was not
statistically different from that to be expected in the general
population. The Department of Health was not able to establish a
link between these leukemia cases and any specific cause. They
specifically ruled out exposure to releases from the Weldon Spring
site.
Even though the risks to the general public from this action
are estimated to be very low, the DOE, under its ALARA process,
will ensure that the risks are reduced to extremely low levels. It
is highly unlikely that there will be any health impacts associated
with radiation exposure resulting from this action.
Issue 24
Comment. What will become of the quarry after the bulk
wastes have been removed?
Response. After the bulk wastes have been removed, detailed
studies will be performed to evaluate the need for additional
remedial action (such as the removal of residual materials from the
cracks and fissures in the quarry and the remediation of
contaminated groundwater). The water treatment plant at the quarry
will continue to operate to keep the quarry pond from refilling.
After all necessary remedial actions are complete, the quarry area
will be stabilized. Plans for stabilizing this area will be
prepared cooperatively with State of Missouri agencies such as the
Missouri Departments of Natural Resources and Conservation to
ensure that future uses of the quarry area are consistent with
those planned for the surrounding Weldon Spring Wildlife Area.
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Issue 25
Comment. How do we know that sufficient funds will be
available to complete all necessary remedial actions.
Response. Funding for remediation of the Weldon Spring site
is provided by Congress on an annual basis. There is no guarantee
•that all required funds will be made available each and every year.
However, cleanup projects such as that at the Weldon Spring site
are currently top priority activities within the DOE. In addition/
because the site is on the National Priorities List (NPL), EPA
Region VII is responsible for ensuring the adequacy of the cleanup.
Representatives from EPA Region VII have made it very clear that
they will not delist the site from the NPL until they are satisfied
that all required remedial actions have been completed.
Issue 26
Comment. The proposed plan states that Alternative 5 is
preferred by the DOE. Has the DOE already decided on implementing
this alternative?
Response. The DOE had not yet reached a decision on
implementing Alternative 5 when the proposed plan was issued to the
public. However, this alternative was preferred by the DOE. This
joint EPA/DOE record of decision provides the rationale for
selection of this alternative.
Issue 27
Comment. The DOE has apparently already concluded that
truck transport of the bulk wastes is the preferred mode of
transportation. Additional consideration should be given to using
the existing rail spur between the quarry and chemical plant area.
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Response. The existing rail spur between the quarry and
chemical plant area is in a state of disrepair and would require a
significant amount of effort (and cost) to upgrade for use. The
results of a recent detailed cost estimate indicate that the rail
option would cost about $1 million more than the haul road option.
In addition, this rail spur crosses State Route 94 three times
between the quarry and chemical plant area. Each crossing presents
a safety concern. The wastes can be safely and efficiently
transported by truck along a dedicated haul road that will be
constructed using portions of the existing rail spur. This
dedicated haul road will cross State Route 94 only once (near the
quarry). Discussions are currently taking place with the State of
Missouri on the use of grade separation where the haul road crosses
Route 94. This would eliminate any crossing of Route 94 by trucks.
Issue 28
Comment. The sorting pad at the temporary storage area
should be completely enclosed and ventilated to minimize airborne
releases of contaminants. In addition, the entire quarry area
should be enclosed during removal of the bulk wastes.
Response. The need for an extensive sorting pad at the
temporary storage area is being reevaluated because the current
plan is to conduct basic waste sorting at the quarry. Although
some sorting may still be required at the temporary storage area,
enclosing the sorting pad with an engineered structure is probably
unnecessary. However, this consideration will be evaluated as
engineering design proceeds.
Enclosing the entire quarry during excavation of the bulk
wastes was considered in the preliminary engineering report and
rejected due to its high cost. In addition, there is simply no
need to enclose the quarry to remove the wastes safely. Radon and
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dust suppression measures will be implemented to ensure that
releases of hazardous contaminants to the atmosphere will be low
and not present a health risk to nearby individuals.
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