PB95-964615
EPA/ROD/R10-95/125
January 1996
EPA Superfund
Record of Decision:
Teledyne Wah Chang Albany Site,
Surface & Subsurface O.U., Millersburg, OR
9/27/1995
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RECORD OF DECISION
DECLARATION, DECISION SUMMARY,
AND
RESPONSIVENESS SUMMARY
FOR
FINAL REMEDIAL ACTION FOR
SURFACE AND SUBSURFACE SOIL
OPERABLE UNIT
TELEDYNE WAH CHANG ALBANY SUPERFUND SITE
MBLLERSBURG, OREGON
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SITE NAME Aiii) LOCATION
Teledyne Wah Chang Albany
Millersburg, Linn County, Oregon
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial actions for the surface and subsurface soils
operable unit at the Teledyne Wah Chang Albany Site (She or TWCA She), in Millersburg, Linn
County, Oregon, which were chosen in accordance with the requirements of the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), as amended by the
Superfund Amendments and Reauthorization Act of 1986 (SARA), 42 U.S.C. §9601 et. seq.. and, to
the extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan, 40
C.F.R. Part 300, Published in 55 Fed. Reg. 8666, et. sea., on March 8, 1990 (NCP). This decision
is based on the administrative record for the Site.
The State of Oregon concurs with the selected remedy.
ASSESSMENT OF THE Sl'l'lS
Actual or threatened releases of hazardous substances from this Site, if not addressed by implementing
the response actions selected in this Record of Decision (ROD), may present an imminent and
substantial endangerment to public health, welfare, or the environment.
DESCRIPTION OF THE SELECTED REMEDY
The remedial actions described below are the final CERCLA response actions planned for the surface
and subsurface soil operable unit at the Site. Teledyne Wah Chang Albany is an active operating
facility which primarily manufactures zirconium metal from zircon sands. The processing of the
zircon sands generates sludge, waste water, residues and gases as by-products. The cleanup actions
described hi this ROD address the threats to public health posed by radionuclides and their decay
products, polychlorinated biphenyls (PCBs), and other contaminants at the Site.
The selected remedy combines source remediation with institutional controls to reduce risks to human
health and the environment posed by contaminants in surface and subsurface soil at the TWCA Site.
The selected remedy consists of the following:
Excavation of contaminated material exceeding the gamma radiation action level of 20
/irem/hour above background levels;
Transportation of the excavated material to an appropriate off-site facility for disposal;
For areas of the Site where modelling indicates that radon concentrations in future buildings
could exceed 4 pCi/liter, institutional controls requiring that future buildings be constructed
using radon resistant construction methods;
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Requirement that information on areas of subsurface I-CL ?nd radiouuciide contamination
which do not pose a risk if they are not disturbed, be incorporated into the TWCA facilities
maintenance plan, and be made available to future Site purchasers or regulatory agencies;
Because the determination that action is not required for certain areas of the Site is based on
scenarios which do not allow unrestricted use, should excavation occur as part of future
development of the TWCA Main Plant or the Soil Amendment Area, excavated material must
be properly handled and disposed of in accordance with Federal and State laws; and
Institutional controls requiring that land use remain consistent with current industrial zoning.
Except as expressly stated in CERCLA, in the NCP, or in this ROD, this ROD is not- designed to
address TWCA's ongoing operations or to preclude the need for TWCA's ongoing operations to
comply with other environmental laws or regulations. Regulation of TWCA's ongoing operations is
covered under RCRA and under other State and Federal environmental laws. Except as otherwise
stated in this ROD, determinations in this ROD are intended to apply to Site geographic areas rather
than to ongoing plant operations.
The determinations made in this ROD regarding contamination of surface and subsurface soils apply
to areas of the Site investigated during the RI/FS, and are based on information from the RI/FS. As
TWCA is an active operating facility, some on-site conditions may have changed since the RI/FS.
Material placed in CERCLA investigated areas subsequent to the RI/FS sampling may not necessarily
be addressed by this ROD, but may be investigated and addressed under RCRA. Similarly, not all
excavations on the Site are covered by this ROD.
STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the environment, complies with Federal and
State requirements that are legally applicable or relevant and appropriate to the remedial action, and is
cost-effective. This remedy utilizes permanent solutions and alternative treatment or resource
recovery technologies to the maximum extent practicable. Since treatment of the principal threats
posed by the Site is not practicable at this time, it does not satisfy the statutory preference for
treatment as a principal element.
Because this remedy will result in hazardous substances remaining on Site above health-based levels,
a review will be conducted within five years after commencement of the remedial action to ensure that
the remedy continues to provide adequate protection of human health and the environment.
Date /Regional Administrator
'j^EHvlromnental Protection Agency
' Region 10
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TABLE OF CONTENTS
DECLARATION Dl
1.0 INTRODUCTION 1
1.1 Site Name and Location 1
1.2 Lead and Support Agency 1
1.3 Administrative Record 1
2.0 SITE DESCRIPTION I . 1
2.1 Setting 1
2.2 Topography 3
2.3 Land Use 3
3.0 SITE BACKGROUND ... , 3
3.1 Site History 3
3.2 Plant Processes 5
3.3 Radioactive Materials Handling ........ . . . 7
3.4 Past Remedial and Removal Activities .....' 8
3.5 Operable Unit 2: Groundwater and Sediments - - • • • 8
3.4.1 Sludge Ponds Operable Unit 8
3.4.2 Supplementary Removal Action at Schmidt Lake 9
3.4.3 Soil Removal in Fabrication Area. 9
4.0 COMMUNITY RELATIONS 12
5.0 SCOPE AND ROLE OF RESPONSE ACTION WITHIN SITE STRATEGY 14
6.0 SITE CHARACTERISTICS 16
6.1 Geology and Soils 16
6.2 Extent of Soil Contamination 16
6.3 Chemical and Radionuclide Contamination on the Main Plant and the Farm
Ponds Area 22
6.3.1 Soil Contamination in the Farm Ponds Area 22
6.3.2 Soil Contamination in the Extraction Area 23
6.3.3 Soil Contamination in the Fabrication Area . . 23
6.3.4 Soil Contamination in the Solids Area . . . 23
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6.4 Radiological Survey (Gamins Radiation and Rsdon Investigation at TWCA) .... 31
6.4.1 Gamma Radiation Survey 31
6.4.1.1 Background Contaminant Levels 31
6.4.1.2 Main Plant 32
6.4.1.3 Soil Amendment Area 39
6.4.2 Calculated Radon Levels in Future Buildings : 39
7.0 SUMMARY OF SITE RISKS 45
7.1 Human Health Risks 45
7.1.1 Approach to Human Health Risk Assessment 45
7.1.2 Chemicals of Concern 46
7.1.3 Toxicity Assessment . . 46
7.1.4 Exposure Assessment 48
7.1.5 Risk Characterization 52
7.1.6 Chemical and Radionuclide Risks 53
7.2 Human Health Risks from Exposure to Surface Gamma Radiation and
Inhalation of Radon 56
7.2.1 Gamma Radiation Risks 60
7.2.2 Risks from Radon Inhalation 60
7.3 Risk Assessment Uncertainty 60
7.4 Environmental Risk Characterization 68
7.5 Conclusions 68
7.6 Risk Management Decisions 68
8.0 DESCRIPTION OF ALTERNATIVES 70
8.1 ARARs Common to the Remedial Actions Proposed for the Site 70
8.1.1 Health and Environmental Protection Standards for Uranium and
Thorium Mill Tailings (40 CFR Pan 192.12) 70
8.1.2 Oregon Statutes and Regulations 71
8.2 Remedial Action Alternatives 72
8.2.1 Alternative 1 - No Further Action 72
8.2.2 Alternative 2 - Limited Excavation 72
8.2.3 Alternative 3 - Capping of Areas Above Selected Gamma
Radiation Action Levels 73
8.2.4 Alternative 4 - Additional Excavation of Soil 76
u
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9.0 COMPARATIVE ANALYSIS OF ALTERNATIVES 78
9.1 Threshold Criteria 78
9.1.1 Overall Protection of Human Health and the Environment 78
9.1.2 Compliance with Applicable or Relevant and Appropriate
Requirements (ARARs) 78
9.2 Primary Balancing Criteria 79
9.2.1 Long-Term Effectiveness and Permanence 79
9.2.2 Reduction of Toxicity, Mobility, or Volume Through
Treatment 79
9.2.3 Short-Term Effectiveness 79
9.2.4 Implementability 80
9.2.5 Projected Costs 80
9.3 Modifying Criteria 80
9.3.1 State Acceptance •:..--. 80
9.3.2 Community Acceptance " 80
10.0 SELECTED REMEDY 81
10.1 Remedial Action for Gamma Radiation 82
10.2 Remedial Action for Radon 82
10.3 Chemical and Radionuclide Contamination 89
10.4 CERCLA FrverYear Review 90
10.5 Costs : 90
11.0 STATUTORY DETERMINATIONS 92
11.1 Protection of Human Health and the Environment 92
11.2 Compliance with Applicable or Relevant and Appropriate Requirements
(ARARs) 92
11.3 .Cost Effectiveness .'.' 94
11.4 Utilization of Permanent Solutions and Resource Recovery Technologies to the
Maximum Extent Practicable 95
11.5 Preference for Treatment as a Principal Element 95
11.6 Community Acceptance 95
11.7 Conclusions , 95
12.0 DOCUMENTATION OF SIGNIFICANT DIFFERENCES 96
APPENDIX A Responsiveness Summary A-l
ui
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LIST OF TABLES
6-la Farm Ponds Area Surface Soil Contaminant
Concentrations 24
6-lb Farm Ponds Area Subsurface Soil Contaminant Concentrations 25
6-2a Extraction Area Surface Soil Contaminant
Concentrations 26
6-2b Extraction Area Subsurface Soil Contaminant Concentrations 27
6-3a Fabrication Area Surface Soil Contaminant Concentrations 28
6-3b Fabrication Area Subsurface Soil Contaminant
Concentrations 1 29
'* -.
6-4 Summary of Main Plant External Gamma Exposure
Data 33
6-5 Summary of Soil Amendment Area External Gamma
Exposure Data . '. 40
6-6 Parameters for Radon Model '.- V 42
6-7 Potential Radon Concentrations in Future
Buildings - Main Plant Subareas . 43
6-8 Potential Radon Concentrations in Future
Buildings - Soil Amendment Area 44
7-1 Chemicals of Potential Concern and Selection
Criteria 47
7-2 Toxicity Factors 49
7-3a Exposure Assumptions for Subsurface Soil
Pathways 53
7-3b Exposure Assumptions for Surface Soil
Pathways 53
7-3c Exposure Assumptions for Agricultural Pathways , 53
7-4a Summary of Sample-Specific Risks for Surface
Soils 54
IV
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l-4b Summary of Sampie-Specitlc Ris'c-; for Subsurfecs
Soils '. ; 55
7-5 Exposure Assumptions for External Gamma Radiation Pathways 57
7-6 Exposure Assumptions for Radon Inhalation
Pathways 59
7-7a Summary of Cancer Risk Estimates for Gamma Radiation - Main Plant Area -
Industrial Scenario 61
7-7b Summary of Cancer Risk Estimates for Gamma Radiation - Soil Amendment Area -
Farm Worker Scenario 62
7-7c Summary of Cancer Risk Estimates for Gamma Radiation - Soil Amendment Area -
Industrial Scenario . 63
7-7d Summary of Cancer Risk Estimates for Gamma Radiation - Soil Amendment Area -
Residential Scenario 64
7-8a Summary of Cancer Risk Estimates for Radon Inhalation - Main Plant Subareas -
Industrial Scenario . 65
7-8b Summary of Cancer Risk Estimates for Radon Inhalation -
Soil Amendment Area - Industrial Scenario 66
7-8c Summary of Cancer Risk Estimates for Radon Inhalation -
Soil Amendment Area - Residential Scenario 67
8-1 Residual Risk Following Remediation to Specified Action Level . . : 75
10-1 Cost Breakdown for the Selected Remedy 91
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LIST OF FIGURES
2 - 1 Location Map 2
3 - 1 Past Disposal Areas 4
3-2 Zirconium Manufacturing Process '. . . 6
3-3 Location of Boring B-91-5 9
6-1 Fence Diagram Geologic Cross Section of Solids Area 17
6-2 Remedial Sectors 18
6 - 3a Surface Soil Sampling Locations - Extraction Area 19
6 - 3b Surface Soil Sampling Locations - Fabrication Area 20
6 - 3c Surface Soil Sampling Locations - Farm Ponds Area . 21
6-4 Solids Area Source Location 30
6 - 5a Gamma Survey Results - Parking Lot Area 36
6 - Sb Gamma Survey Results - Former Sand Unloading Area 37
6 - 5c Gamma Survey Results - Schmidt Lake 38
6-6 Gamma Survey Results - Soil Amendment Area 41
10 - la Areas Exceeding Action Level For Gamma Radiation83
Parking Lot Area . . 83
10 - Ib Areas Exceeding Action Level For Gamma Radiation
Former Sand Unloading Area 84
10 - Ic Areas Exceeding Action Level For Gamma Radiation
Schmidt Lake 85
10 - 2a Areas Exceeding Radon Action Level
Extraction Area 86
10 - 2b Areas Exceeding Radon Action Level
Fabrication Area 87
10 - 2c Areas Exceeding Radon Action Level
Soil Amendment Area . 88
VI
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1.0 INTRODUCTION
1.1 Site Name and Location
Teledyne Wah Chang Albany
Millersburg, Oregon
1.2 Lead and Support Agency
The U.S. Environmental Protection Agency (EPA) is the lead agency for this Superfund Site. The
State of Oregon, through the Oregon Department of Environmental Quality (ODEQ), has reviewed
and concurs with the response activities planned at the She.
1.3 Administrative Record
This ROD is based on the Administrative Record (AR) for this Site and will become pan of the AR
file, in accordance with §300.825(a)(2) of the NCP. The AR is available for review at the EPA
Regional Office, 1200 Sixth Avenue, Seattle, Washington, 98101, and at the Albany Public Library,
in Albany Oregon. An index of the AR is included with this ROD.
2.0 SITE DESCRIPTION
2.1 Setting .
The Teledyne Wah Chang Albany Site (Site or TWCA Site) is located in Millersburg, Oregon, an
industrial-based community two miles north of downtown Albany (Figure 2-1). The Site is
approximately 20 miles south of Salem, 65 miles south of Portland, 60 miles east of the Pacific
Ocean, and adjacent to the Willamette River. Portions of the TWCA Site are within the river's 100-
year and 500-year flood plains.
The TWCA plant is bounded on the east by Old Salem Road and Interstate 5 (1-5). The land east of
the plant is used mainly for residential and commercial purposes. The land west of the Willamette .
River, which forms the western boundary of the plant, is used for agriculture. The land surrounding
the Farm Ponds Area to the north of the Main Plant is also used for agricultural purposes.
The city of Albany had a population of approximately 29,000 in 1990; Millersburg had a population
of about 700 people. The TWCA Site is located within an area that is zoned for heavy industry.
Industrial facilities closest to the TWCA Site include: a particle .board plant, a resin plant, a wood
flour processing plant, and a closed plywood mill.
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NORTH
ALBANY
MUIersburg
{-/Soil Amendment
Area
Interstate 5
, Fabrication
.-*»
i"** .
. • '; 1
' A
solids Area -
4
/ Extraction Area
Figure 2-1
Location Map
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2.2 Topography
TWCA is located within the broad and relatively flat Willamette Valley which was formed by the
Willamette River as it meandered back and forth between the Coast Range mountains to the west and
the Cascade Mountains to the east. The ground surface in the vicinity of TWCA slopes westward
towards the river with a gradient of approximately 11 feet per mile.
2.3 Land Use
The TWCA Superfund Site covers the 110 acre Main Plant and the 115 acre Farm Ponds Area
located 3/4 mile north of the Main Plant (Figure 2-1). The Main Plant is organized into the
following areas; the Extraction Area (south of Truax Creek), the Fabrication Area (north of Truax
Creek), and a Solids Storage Area west of the Burlington Northern Railroad. The Farm Ponds Area
contains the plant's wastewater treatment ponds, four 2-1/2 acre solids storage ponds, and the 50 acre
Soil Amendment Area. The Soil Amendment Area has been primarily used in the past for
agriculture.
3.0 SITE BACKGROUND
3.1 Site History
Teledyne Wah Chang operations at the TWCA Site began in 1956 when, under contract with the U.S.
Atomic Energy Commission, Wah Chang Corporation reopened the U.S. Bureau of Mines Zirconium
Metal Sponge Pilot Plant. Construction of new facilities, at the location of the existing plant, began
in 1957. These facilities were established primarily for the production of zirconium and hafnium
sponge; however, tantalum and niobium pilot facilities were also included. Melting and fabrication
operations were added in 1959. TWCA was established in 1967 after Teledyne Industries, Inc.,
purchased the Wah Chang Corporation of New York. In 1971, the plant became a separate
corporation, Teledyne Wah Chang Albany.
Beginning in 1957, waste materials from TWCA's processes were placed in unlined ponds on the
facility. Examples of unlined ponds used for disposal of waste sludges and other materials in the past
include the V-2 Pond, Schmidt Lake, and the Lower River Solids Pond (LRSP) (Figure 3-1).
From 1972 until 1978 chlorinator residues from TWCA's sand chlorinator process were placed in a
separate pile north of Schmidt Lake. This practice was discontinued hi 1978, when the contents of
the pile were removed and transported off Site to a permitted low level radioactive waste disposal
facility (Figure 3-1).
Solid residues generated during the development and operation of nonferrous metals manufacturing
processes at the plant site were placed hi a resource and recovery pile. The major material placed in
the pile was magnesium chloride. From 1983 through 1988 TWCA recovered material from this pile
to produce magnesium oxide for use hi its ongoing processes (Figure 3-1).
The V-2 Pond was used for temporary storage and pretreatment of primarily hydrous metal precipitate
and imnfartflri lime solids. The use of mis pond was discontinued in 1979. The V-2 Pond was
emptied hi 1989. Confirmatory soil sampling of the pond was conducted hi late 1991 and early 1992.
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Chloride -.,
_ „ „„ Chlorinator
Rcsolirco Recovy plle
Lower River
Solids Pond
StREAM BOUNDARY
TOPOGRAPHICAL LINt
.. DIRT ROAD
:TWCAMaln Plant
Figure 3-1
Past Disposal Areas
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The V-2 Pond is currently filled with gravel and soil (Figure 3-1). '
The unlined sludge ponds have attracted the attention of regulatory agencies (U.S. Environmental
Protection Agency (EPA) and Oregon Department of Environmental Quality (ODEQ)) and the public
for many years, particularly because of the presence of radioactive materials, which was first
confirmed by the Oregon State Health Division in 1977. Waste sludges (toe solids) generated prior
to 1979 were contained in the LRSP, Schmidt Lake, Arrowhead Lake, and the V2 Pond. Much of
the public concern has focused on the LRSP and Schmidt Lake because of their proximity to the
Willamette River.
Under an Oregon Department of Environmental Quality permit, some of the solids generated prior to
1976 were used as a beneficial soil amgndmgnt on land in the Farm Ponds Area (the Soil Amendment
Area). In 1978 TWCA changed its production process which reduced the amount of radioactive
materials in the lime solids. Lime solids generated after 1979 are now contained in 4 ponds located
in the Farm Ponds Area.
Concerns that the unlined sludge ponds were located in the Willamette River floodplain, and that
hazardous materials from the sludge ponds would migrate to soil, surface water, and groundwater, led
to the TWCA facility being proposed for inclusion on the National Priorities List (NPL) in December
of 1982. The TWCA Site was placed on the NPL in October 1983.
3.2 Plant Processes
TWCA is an active, operating, producer of zirconium metal. Zircon sand, the principal ore, is
generally imported from Australia. A schematic diagram showing TWCA's process for producing
zirconium and hafnium is shown in Figure 3-2. Zircon sand (zirconium orthosilicate) is concentrated
by gravity, electrostatic, and magnetic methods to remove all but a small amount of impurities before
being shipped to the TWCA facility. Zircon sands typically contain small amounts of radioactive
elements such as uranium and thorium which are concentrated during the TWCA production process.
In addition, the zircon sands will contain 1 to 5 percent fraftijurn which becomes a co-product with
zirconium.
The zircon concentrate is combined with petroleum coke, and mixed in a ball mill before feeding to a
chlorination reactor where at high temperatures the zirconium orthosilicate is converted to zirconium-
hafnium tetrachloride and silicon tetrachloride. The hafafaim and zirconium are separated by mixing -
the zirconium-hafhium tetrachloride with methyl isobutyl ketone (ME3K), containing ammonium
thiocyanate. This portion of the process separates the hafnium into an organic phase and the
zirconium into an aqueous phase. Hafnium is removed from the organic phase by stripping with
sulfuric acid, and then it is formed into a solid by precipitation with ammonium hydroxide. The
precipitate is filtered and heated to form hafnium oxide. Zirconium is removed from the aqueous
phase by precipitation with sulfuric acid. The zirconium precipitate is also filtered and heated to form
zirconium oxide. MIBK and ammonium thiocyanate are purified and recycled.
The zirconium and hafnium oxides follow similar paths to metal production. Zirconium oxide is
mixed with petroleum coke and fed to a chlorination reactor to form zirconium tetrachloride.
Elemental magnesium is then reacted with the zirconium tetrachloride to form a sponge-like material
consisting of magnesium chloride and zirconium. The magnesium chloride is physically removed
from the zirconium sponge and sold as a byproduct. The zirconium sponge is consolidated into ingots
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Figure 3-2
Zirconium Manufacturing Process
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by first crushing, blending snd pressing the rpongr into briqaettes. The briquettes are then welded
together with an electron beam to form an electrode which is melted and cast into homogenized ingots
in a vacuum arc furnace. The cast zirconium ingots are then fabricated into numerous shapes and
forms such as forgings, plate, sheet, foil, tubing, rod, and wire. The fabrication process can involve
caustic cleaning, degreasing, and/or pickling.
3.3 Radioactive Materials Handling
In March 1978, a Naturally Occurring Radioactive Materials (NORM) license was granted to TWCA
to transfer, receive, possess and use zircon sands and industrial byproducts containing licensable
concentrations of radioactive material. TWCA currently disposes of its radioactive waste material at
the U.S. Ecology Low Level Radioactive Waste Site located on the Hanford Reservation in
Washington and operates under the provisions set forth in the 1978 NORM license. •
3.4 Past Remedial and Removal Activities
3.4.1 Sludge Ponds Operable Unit
The LRSP and Schmidt Lake lie adjacent to each other in the western portion of the TWCA Site, next
to the east bank of the Willamette River, between Murder Creek to the north and Truax Creek to the
south (Figure 3-1).
In the summer of 1988, in order to expedite cleanup, EPA and TWCA identified the sludges in the
LRSP and Schmidt Lake as a separate operable unit from the rest of the Site for the following
reasons:
a) the sludges in the unlined ponds were a likely source of groundwater contamination;
b) the LRSP and Schmidt Lake are located in the Willamette River flood plain;
c) the sludges in the ponds contained low levels of radioactive materials, and had been
the focus of community concerns about the Site; and
d) TWCA, in response to the community concerns wished to clean up the ponds without
waiting for the full Site RI/FS to be completed.
A Record of Decision (ROD) for an Interim Response Action at the Sludge Ponds Unit was signed by
EPA on December 28, 1989. The Operable Unit ROD presented the selected remedial action for the.
sludge ponds unit.
The major components of the selected remedy consisted of:
- Excavation and removal of the sludges from the ponds.
- Partial solidification of the sludge with a
solidification agent such as Portland cement.
- Construction of a monocell at an off-site permitted solid waste facility.
- Transportation of the solidified sludge to the off-she
facility and disposal in the monocell.
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- Long-term operation and maintenance (OocM) of the off-
site monocell.
On February 14, 1991, EPA issued a Unilateral Order (Order) to TWCA for design and
implementation of the selected remedy for the operable unit. In June of 1991, construction of the off-
site monocell at the Finley Buttes Landfill in Boardman, Oregon was completed. Excavation and
removal of the sludges began in July of 1991 and was completed in November 1991. Approximately
100,000 cubic yards of solids (including cement) were transported to the monocell at Finley Buttes.
Cover construction and grass seeding of the monocell was completed in April 1992. On June 30,
1993, EPA issued a Certification of Completion for the Sludge Ponds Operable Unit Remedial Action
to TWCA.
3.4.2 Supplementary Removal Action at Schmidt Lake
In 1991, EPA received information provided by a former TWCA employee that radioactive materials
had been buried in Schmidt Lake in the 1970's. These radioactive materials were buried in drums
which were allegedly located below the sludges that had been the subject of the operable unit remedial
action. Based on this information, EPA requested that TWCA conduct additional geophysical
investigations hi this area. In 1992, pursuant to the additional work provision of the RI/FS Consent
Order with EPA, TWCA conducted an electromagnetic survey in this area. The electromagnetic
survey identified potential additional source materials in and around Schmidt Lake. These source
materials included several corroded metal drums containing sands with elevated-amounts of thorium
and uranium, and an underground storage tank containing liquid petroleum product.
In December 1992, as part of an action referred to as the Schmidt Lake Excavation Project (SLEP),
2,016 cubic yards of materials containing zircon sands with elevated levels of thorium and uranium
were removed from Schmidt Lake and transported by TWCA to the U.S. Ecology low-level
radioactive waste site in Washington for disposal.
3.4.3 Soil Removal in Fabrication Area
In December 1991, during the installation of a soil boring adjacent to the Emergency Services
Building in the Fabrication Area of the Main Plant (Boring B91-5) (Figure 3-3), a floating
nonaqueous oil layer containing 8 percent PCBs was detected. Groundwater in the vicinity of this
boring contained up to 22,500 parts per billion (ppb) PCBs. Additional sampling identified an area of
soil, approximately 30 feet by 30 feet, as a probable source/receptor for the PCB-contaminated oil.
In order to prevent further degradation of water quality resulting from the oil layer, in November
1992 TWCA initiated a removal action in the area. After approval by EPA, TWCA excavated
approximately 230 cubic yards of PCB-contaminated soil and disposed the soil at an off-site permitted
landfill. The source of the oil layer was not identified.
3.5 Operable Unit 2: Groundwater and Sediments
On June 10, 1994, EPA selected the Final Remedial Action for Groundwater and Sediments. This
Operable Unit ROD presented the selected remedial action for surface water, groundwater and
sediments at the Site. The major components of the selected remedy consisted of:
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East Site Boundary
U
Figure 3-3
Location of Boring B-91-5
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For Contaminated Groundwater:
Remediation of groundwaier via groundwater extraction in the Feed Makeup area and
at areas on Site where contaminant concentrations exceed lifetime cancer risk levels of
10** and/or substantially exceed noncancer HI of 1 for worker exposure. Extraction
shall continue until contaminant concentrations in groundwater throughout the She are
reduced to below SDWA MCLs, non-zero MCLGs, or cancer risk levels of 10"6 and
noncancer risk HI < 1 for worker exposure, or until EPA in consultation with ODEQ
determines mat continued groundwater extraction would not be expected to result in
additional cost effective reduction in contaminant concentrations at the Site.
Contaminated groundwater in exceedance of SDWA MCLs, non-zero MCLs, or
cancer risk levels of 10* and noncancer risk HI > 1 for residential use shall be
prevented from migrating off the plant sue, or beyond the current boundary of the
groundwater contaminant plume at the Farm Ponds Area.
Discharge of extracted groundwater to Teledyne Wan Chang Albany's wastewater
treatment plant. Pretreatment of groundwater to comply with CWA requirements
prior to discharge to the wastewater treatment plant.
Treatment or removal of subsurface source material near the Feed Makeup Building
on the main plant.
For Contaminated Sediments!
Slope erosion protection consisting of a geotextile covered by riprap placed along the
banks of Truax Creek to prevent contaminated fill material from entering the creek.
Removal of approximately 3,600 cubic yards of contaminated sediments from the
surface water bodies adjacent to, or flowing through the Site. Additional ecological
characterization prior to removal to determine potential impacts of sediment removal
to the local ecosystem and to provide mechanisms to mitigate those impacts.
Site-Wide Actions:
Deed restrictions and institutional controls on land and groundwater use for both the
main plant and Farm Ponds area. The objective of this component of the remedy is to
ensure that the property and groundwater are used only for purposes appropriate to
the cleanup levels achieved.
Environmental evaluations of currently uncharacterized potential contaminant source
areas, as needed to ensure achievement of groundwater RAOs. The objective of this
component of the remedy is to ensure that contaminant source areas do not adversely
impact the remedy.
10
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* Long-term on-site and off-site groundwater, surface water, and sediment mcnitcric?
which shall include at a minimum the monitoring of on-site wells which are in
exceedance of MCLs and non-zero MCLGs, cancer risk levels of 10"6, and noncancer
risk HI > 1 for residential exposure.
• Review of selected remedy at least once every five years to ensure protection of
human health and the environment.
The groundwater ROD has not yet been implemented. The implementation of the groundwater ROD
will be done concurrently with the Soils Operable Unit (the subject of this current ROD).
11
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•2.0 COMMUNITY RELATIONS
The Revised Draft RI/FS and the Proposed Plan for the Site were originally released to the public for
comment on August 25, 1993. The Proposed Plan addressed remediation for contamination in
groundwater and sediments, and in surface and subsurface soils. Based in part on supplemental RI/FS
data received from Teledyne Wah Chang Albany on December 21, 1993, EPA determined that it
would be more realistic to address remediation of the Site in two parts. On June 10, 1994, EPA
issued a ROD for groundwater and sediments.
This ROD addresses contamination in surface and subsurface soil, as Operable Unit Three. The
Proposed Plan was issued July 21, 1995. The public comment period lasted from August 1 to August
30, 1995. The RI/FS and supporting documentation were made available to the public in the
information repositories maintained at the Superfund Records Center in Region 10's offices in Seattle,
and the Albany Public Library. The notice of availability of the RI/FS documents was published in
the Albany Democratic Herald on July 31,1995.
The proposed plan offered the opportunity to hold a public meeting if sufficient interest was expressed
by the public. Because little interest was expressed, a public meeting was not held.
Past EPA Region 10 community relations activities at the Site have included the following:
• December 1982 - TWCA Site proposed for inclusion on NPL: 60-day public comment period
initiated.
• October 1983 - TWCA Site listed on NPL.
• February-May 1987 - Local citizens and officials interviewed in order to prepare a
Community Relations Plan.
• November 1987 - Final Community Relations Plan issued.
•
• November 1987 - Information Repositories established at Albany Public Library, ODEQ
(Portland), and EPA Region 10 (Seattle).
• November 1988 - RI/FS work plan for entire facility sent out for 30-day public comment
period. Work plan was placed in Information Repositories and a Fact Sheet was published.
• February 1989 - Fact Sheet published announcing EPA's approval of the final work plan.
• June 1989 - Fact Sheet published announcing that TWCA had submitted a draft RI/FS report
to EPA for the Sludge Ponds Operable Unit.
• August 16, 1989 - Interim Action (Operable Unit #1) Proposed Plan published.
• August 18 - October 16, 1989 - Public comment period for the Operable Unit #1 Proposed
Plan.
12
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* September 6, 1989 - Public meeting for the Operable Unit #1 Proposed Flan «".? hs'd in
Albany, Oregon.
• October 11, 1990 - Fact Sheet published announcing expansion of scope of RI to include
identification of potential sources of contamination. Fact Sheet also announced beginning of
negotiations with TWCA for Sludge Ponds Operable Unit remedial action.
• March 5, 1991 - Fact Sheet published announcing issuance of Unilateral Order by EPA to
TWCA for cleanup of Sludge Ponds Operable Unit.
• July 1991 - Local citizens and officials updated and interviewed in order to prepare a Revised
Community Relations Plan.
• October 1991 - Revised Community Relations Plan issued.
• February 19, 1992 - Fact Sheet published announcing issuance of Request for Information
letter by EPA to TWCA regarding the threat of a release of hazardous substances in or
around Schmidt Lake. Fact Sheet also updated continuing RI investigations.
• October 29, • 1992 - Fact Sheet published announcing that TWCA- had- submitted a draft RI/FS
report to EPA for the entire Site. Fact Sheet also updates public on discovery of decayed
metal drums containing zircon sand within Schmidt Lake.
• April 1, 1993 - Fact Sheet published announcing removal of decayed metal drums and
approximately 2,100 cubic yards of contaminated sands from Schmidt Lake.
• August 25, 1993 - Proposed Plan for entire Site Superfund cleanup published.
• August 27-October 27, 1993 - Public comment period for Proposed Plan.
• September 14, 1993 - Public meeting to take comments and answer questions regarding the
Proposed Plan held in Albany, Oregon.
• October 15, 1993 - EPA meets with TWCA to discuss TWCA's objections to Proposed Plan.
• October 22, 1993 - Fact Sheet published updating public on public comment period and
Proposed Plan.
• June 10, 1994 - Fact Sheet announcing the signing of the ROD and detailing major elements
of the cleanup plan.
• July 21, 1995 - Proposed Plan for Surface and Subsurface Soil Operable Unit published.
• July 21, 1995 - Fact Sheet summarizing the Proposed Plan for Final Remedial Action for
Surface and Subsurface Soils and inviting comments during the public comment period.
13
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5.0 SCOPE AND ROLE OF RESPONSE ACTION WITHIN SITE STRATEGY
As with many Superfund sites, the problems at the TWCA Site are complex. TWCA is an active
facility with ongoing operations. As a result, EPA organized the Superfund work into three operable
units (OUs). These are:
• OU One: The sludges in the LRSP and Schmidt Lake.
• OU Two: Contamination in the groundwater and sediments
• OU Three: Contamination in surface and subsurface soils.
EPA selected the remedy for OU One, sludges in the LRSP and Schmidt Lake, in a ROD signed on
December 28, 1989. The selected remedy for OU One has resulted in removal and off-site disposal
of contaminated sludges from the LRSP and Schmidt Lake. This remedial action was completed in
June 1993.
EPA selected the remedy for OU Two, addressing the contamination in groundwater and sediment at
the Site, on June 10, 1994. The remedial actions described in the ROD are designed to deal with
contaminated groundwater and sediment, as well as the sources of die groundwater and sediment
contamination at the facility. The implementation of (he OU Two ROD has been postponed until the
completion of this current ROD for OU Three.
The third OU, the subject of this ROD, addresses the contamination in surface and subsurface soils at
the TWCA Site. Surface and subsurface soils on the TWCA Site are contaminated with PCBs and
radionuclides as well as other contaminants. The decay products of the radionuclides, gamma
radiation and radon, are also present on the Site.
The remedial actions presented in this ROD will address the presently known threats to human health
and the environment posed by contaminated surface and subsurface soil.
TWCA is an operating facility. The facility is currently being inspected under the requirements of
EPA's Resource Conservation and Recovery Act (RCRA). EPA and the Oregon Department of
Environmental Quality (ODEQ) are working together and with TWCA to coordinate the activities of -
the CERCLA and RCRA programs in their regulation of TWCA. The coordination between the two
programs at the facility has led to the following determinations:
Except as expressly stated in CERCLA, in the NCP, or in this ROD, this ROD is not
designed to address TWCA's ongoing operations or to preclude the need for TWCA's
ongoing operations to comply with other environmental laws or regulations. Regulation of
TWCA's ongoing operations is covered under RCRA and under other State and Federal
environmental laws. Except as otherwise stated in this ROD, determinations in this ROD are
intended to apply to Site geographic areas rather than to ongoing plant operations.
The determinations made in this ROD regarding contamination of surface and subsurface soils
apply to areas of the Site investigated during the RI/FS, and are based on information from
the RI/FS. As TWCA is an active operating facility, some on-site conditions may have
/ "
14
-------
changed since the RI/FS. Material placed in CERCLA investigated areas subsequent to the
RI/FS sampling may not necessarily be addressed by this ROD, but may be investigated and
addressed under RCRA. Similarly, not all excavations on the Site are covered by this ROD.
Areas of surface and subsurface soil contamination not addressed during the RI/FS and
therefore not addressed in this ROD, but which are later found to be sources or potential
sources of groundwater contamination are addressed in the Record of Decision for Final
Remedial Action of Groundwater and Sediments Operable Unit, Teledyne Wan Chang Albany
Superfund Site, June 10, 1994. Areas of the Site or contamination at the Site, not addressed
by either the groundwater ROD or this ROD, are subject to investigation and corrective action
under RCRA. For conditions or contamination at the She previously unknown that are later
discovered, such conditions or contamination may be addressed under either RCRA or
CERCLA. In addition, under the NORM license administered by the Oregon Department of
Health, TWCA will be required to remediate remaining radioactive material when the plant
closes.
15
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6.0 SITE CHARACTERISTICS
The TWCA RI was conducted in two phases. Phase I was designed to determine whether
contamination existed in groundwater along the perimeter of the facility. As part of this investigation,
soil borings, surface water and sediments were also sampled. Phase n was designed to locate and
investigate potential sources of contamination at the facility. In recognition of TWCA's concerns, the
EPA CERCLA program agreed that the scope of the RI/FS could be designed so 'as not to interfere
with ongoing operations at the facility. Concerns regarding the potential adverse impact of the RI/FS
on TWCA's ability to remain in operation, were also a factor in EPA's agreement at the time of
scoping of the RI/FS, that TWCA could forego sampling of areas beneath certain active ponds, waste
piles, pavements, and existing buildings and structures at the facility. During the preparation of the
groundwater ROD, it was recognized that, should there be contaminated areas beneath tmsampled
areas, these areas could potentially serve as additional contaminant sources that could continue to
undermine the effectiveness of the remedial action. Because of the potential for these contaminant
sources to adversely impact the effectiveness of the remedy, determination of the nature and extent of
possible contamination in these unsampled areas must necessarily take place at some point in the
future. Integration of such sampling into the normal ongoing operations at the TWCA facility has
been incorporated into the Record of Decision for Final Remedial Action of Groundwater and
Sediments Operable Unit, Teledyne.Wah Chang Albany Superfund Site, June 10, 1994.
6.1 Geology and Sofls
The geology beneath the TWCA Site is typified by a stratigraphic column common to much of
Oregon's central Willamette Valley. The column consists of five stratigraphic units which in order of
youngest to oldest are: recent alluvium, Willamette Silt, Linn Gravel, Blue Clay (present in
stratigraphic lows of the Spencer Formation), and Spencer Formation. A geologic cross section
showing these units beneath the Solids Area is shown in Figure 6-1. Engineered fill is also present in
many locations within the Main Plant area. The stratigraphic column at the Farm Ponds Area
consists of Willamette Silt (brown silt and basal gray clay), Linn Gravel, and Blue Clay.
6.2 Extent of Sofl Contamination
For purposes of the RI, the TWCA Site was divided into five areas, termed "remedial sectors". The.
remedial sectors, which are. shown in Figure 6-2, include: 1) the Farm Ponds Area, 2) the Extraction
Area, 3) the Fabrication Area, 4) the Solids Area, and 5) the Surface Water Remedial Sector. The
subject of this ROD is the surface and subsurface soil contamination of 1) the Farm Ponds Area
(north of the TWCA Main Plant), and on the TWCA Main Plant 2) the Extraction Area, 3) the
Fabrication Area, and 4) the Solids Area.
The remedial sectors were subdivided into areas based on current or past manufacturing activities
conducted in each area. Finally, each area was divided into smaller subareas. Surface soil samples
were taken from each subarea. The purpose for this approach was to find localized areas of soil
contamination within the much larger area of the Site. Subsurface soil samples were taken from areas
of potential source locations. Figures 6-3a, b, and c show the surface sample locations across the
Site. Samples were taken in areas which would not impact ongoing TWCA operations.
16
-------
Fill UATERIAl . WaLOMOEOIUIANOUUII
OMVa WITH H.T. (ANA AND
. WOOD ANP UtTAl MM!
ItiSilr""* •»** «we«n««o
oioini to MW OW.MOHH
UQHTOIUr.WICACCOMMWOUO
-RMNtO
MNM'ONt WITH CMOONACCOUI
u*i IRMI MONO ecooma
Diagram
Cross Section of
VOICAMC now NtMl Tor or
pHM i
FORSOdOLASSIFICAi
' REfEflTOASIM D14M
Solids Area
-------
Soil Amendment Area
Farm Ponds Area
/ U \ 1
SURFACE WATER
REMEDIAL SECTOR
EXTRACTION
AREA
LEGEND
STREAM BOUNDARY
DIRT ROAD
V
i \cvcngM\neasr\nuscivicz-ijete
Figure 6-2
Remedial Sectors
-------
CHEMICAL
UNLOADING
AREA
SCAUEINfTCT /
.0 100 200
----- STREAM BOUNDARY
^_lt>-^ TOPOGRAPHICAL LINE
- _ - ORT ROAD
_ - EMSTMC FENCE
MST^ SAMPLE AREAS
• W«MX2«3 CRAB SAMPLE LOCATION
Figure 6-3a
Surface Soil Sampling Locations
Extraction Area
-------
STREAM BOUNDARY
fP"^ TOPOGRAPHICAL ONE
- — - WRT ROAD
EJOSTDNC FENCE
tj?f-<»;i SAMPLE AREAS
L.
n-OZ(c} CRAB SAMPLE LOCATION
100 200
Figure 6-3b
Surface Soil Sampling Locations
Fabrication Area
-------
BACKGROUND
SUBTLE AflEA mrP)
KURDS'
STREAM BOUNDARY
-,_ — WRTROAO
. . . . SURFACE SOU. SAMPUNC TRANSECT
f?\ BACKGROUND SURFACE SOR.
V^ SAMPLE AREA (APPROC LOCATION.
AREA NOT TO SCALE)
FP-C7OS CRAB SAMPLE UXMTMNS
Figure 6-3c
Surface Soil Sampling Locations
Farm Ponds Area
-------
The Surface Water Remedial Sector, and groundwater and sediment contamination in the other
remedial sectors, was covered in the Record of Decision for Final Remedial Action of Groundwater
and Sediments Operable Unit, Teledyne Wan Chang Albany Superfund Site, June 10, 1994.
Gamma radiation and radon were investigated as a supplemental Radiological Survey after the
completion of the other portions of the RI/FS. The presence of radium in soils indicated that risks
from exposure to gamma radiation and radon could potentially pose an unacceptable Site risk. In
order to accurately investigate these risks, EPA determined that it would be appropriate to collect
gamma radiation and radon measurements to supplement the Site investigation. Results of the
supplemental investigation are presented separately in the Site Characterization Section (Section 6.0)
and Summary of Site Risks (Section 7.0). The reason for mis organization are two fold: 1) the
investigation of gamma radiation and radon was carried out separately and with different methodology
than the rest of the RI/FS, and 2) based on the results of the risk assessment (Section 7.0), risks from
ingestion and inhalation of chemicals and radionuclides were not significant and do not require action,
while the risks from exposure to gamma radiation and inhalation of radon are significant and do
require remedial action.
6.3 Chemical and RadKonnclide Contamination on the Main plant and the Farm
Ponds Area
In the following sections, tables of contaminant concentrations show only those contaminants with
concentrations exceeding a risk level of Ixlfr7 or a hazard index of 0.1 (and therefore meet
contaminant of concern screening criteria, see Section 7.0 for an explanation of the risk assessment
process, and the scenarios used). In addition to the tables, areas on the Site where surface or
subsurface contaminant concentrations are noteworthy are discussed in the text. For radionuclides,
this discussion covers only soil concentrations of radium and thorium. Radioactive daughter products,
Gamma radiation and radon, are covered in Section 6.4.
63.1 Soil Contamination in the Farm Ponds Area
The Farm Ponds Area is located approximately 3/4 mile north of the Main Plant, and contains four 2-
1/2-acre solids storage ponds (Figure 6-3c). These ponds received lime solids generated in TWCA's
industrial wastewater treatment plant. The ponds are constructed with a soil-bentonite liner. The
ponds received waste water treatment sludges between 1979 and 1993, and are regulated under the -
National Pollutant Discharge Elimination System (NPDES) program.
The lime solids are similar in composition to the sludges that were placed hi the LRSP and Schmidt
Lake prior to 1979. However, the Farm Ponds solids have a lower concentration of radionuclides.
The Soil Amendment Area, which was the main focus of the soil investigation in the Farm Ponds
Area, is a 47.8-acre tract located directly north of the Farm Ponds (Figure 6-3c). In 1975 and 1976,
TWCA obtained solid waste permits from the Oregon Department of Environmental Quality to use
solids from the primary wastewater treatment plant experimentally as a soil amendment These solids
were applied once in 1976. The solids were similar in composition to mat of the LRSP and Schmidt
Lake and probably contained low-level metals, radionuclides, and organic compounds.
22
-------
Contaminant concentrations in the surface and subsurface soils in the Farm Ponds Area are shown in
Tables 6-la and b. The Soil Amendment Area had elevated concentrations of PCBs,
hexachlorobenzene (HOB), thorium, and radium.
6.3.2 Soil Contamination in the Extraction Area
The Extraction Area comprises the southern portion of the Main Plant (see Figure 6-2). Surface
sample locations are shown in Figure 6-3a.
A list of contaminants and their concentrations which are found in the surface and subsurface soil of
the Extraction Area is shown in Tables 6-2a and b. Surface soils collected from the chemical
unloading area along the west side of the Extraction Area contain elevated levels of HCB, PCBs,
polyaromatic hydrocarbons (PAHs), and thorium. The chemical unloading area serves as a point for
rail and trailer unloading and temporary storage of chemicals and other production materials.
Soils surrounding the V2 Pond contain elevated amounts of thorium and radium. The V2 Pond was
used from 1960 until 1979 as a wastewater.solids holding pond as part of a previous wastewater
treatment system. The pond solids consisted primarily of metal precipitates and unreacted lime.
Radium concentrations up to 54 pCi/gram were found in residuals remaining in the sidewalk of the
V2 pond after sludges from this area were removed in 1989. Excavation *>f the sidewalk was stopped
pending imminent collapse of a tank over the excavation area. The pond was filled with soil and
gravel. This area did not show an increase in surface gamma radiation during the gamma survey (see
Section 6.4.1)
633 Sofl Contamination in the Fabrication Area
The Fabrication Area occupies approximately SO acres on the northern portion of the Main Plant
(Figure 6-2). The area is bounded by Truax Creek to the south. Murder Creek to the north,
Burlington Railroad tracks to the west, and Willamette Industries and Southern Pacific railroad tracks
to the east.
Figure 6-3b shows sample locations in the Fabrication Area. A summary of surface and subsurface
soil contamination in the Fabrication Area is shown in Tables 6-3a and b. High concentrations of
PCBs were found in subsurface soils in the southeast portion of the Fabrication Area. The PCBs in
the vicinity of the Emergency Services Building were previously excavated (see Section 3.4.3);
however, they are still present in the southern region of this area where excavation did not take place
(Boring B-02).
Relatively high radium concentrations were found hi Boring B-2 and 691-06 ranging from 7.4 pCi/g
to 26 pCi/g at 13 to 20 feet below grade.
63.4 Sofl Contamination in the Solids Area
The Solids Area covers approximately 20 acres and is located west of the Main Plant between the
Burlington Northern Railroad and the Willamette River (Figure 6-2). The area contains four separate
potential source areas which are shown in Figure 6-4. These potential source areas include the
Lower River Solids Pond (LRSP), Schmidt Lake, the Magnesium Resource Recovery Pile, and the
Chlorinator Residue Pile. The LRSP and Schmidt Lake received sok'ds from TWCA's existing
23
-------
Table 6-la
Farm Ponds Area Surface Soil Contaminant Concentrations
AmJyte
Number of
Detections
(Number of
Hexachlorobenzene
6(14)
PCBs(ppm)
Tool PCBs
5(14)
Avenge
Deiocud
945
frjfa^lHUfff*
ftfnmf*t
Location of
M2jumun
2.000
SA-02
I.I
1.4
Meals
-------
Table 6-lb
Farm Ponds Area Subsurface Soil Contaminant Concentrations
Analyte
Number of
Detections
(Number of
Samples)
Average
Detected
Concentration
Maximum
Detected
Concentration
Semrrolatile Organic Compounds (ppb)
Hexachloro benzene
PCBs(ppm)
Total PCBs
Metals (ppm)
Thorium
US)
2(5)
16(18)
240
2.40
0.035
- 0.041
Location of
Maximum
Background
Level
SB-SA-02
NO
SB-SA-05
ND
5.4
13.6
SB-SA-05
7.47
Radionoclide (pCi/g)
Radium-226
Radium-228
5(5)
5(5)
1.20
1.22
ND = Not detected.
1.70
1.60
SB-SA-02
SB-SA-02
1.2
1.5
..
-------
Table 6-2a
Extraction Area Surface Soil Contaminant Concentrations
Analyic
Number of
Petcctions
(Nomber of
Samples)
Avenge
Doeocd
Cfmrnnramni
Detected
Cnnnmmtinn
Maximum
ffof t^rTifr^f
Level
Sennvoiadle Organic Compounds (ppb)
Benzo(a)anthracene
Benzo(a)pyiene
Benzo(b)fluonntbene
BenzoOOfluoranihene
Chrysme
Dibenzo(a,h)amhncene
Hexacblorobenzene
Indeno(U.3-cd))pyrere:
PCBs(ppm)
Total PCBs
13(26)
11(26)
14(26)
12(26)
15(26)
3(26)
13(26)
9(26)
195
ISO
208
273
303
76
1 .370 . .
126
19(26)
2.8
AoCCUS (ppOl)
Chromium
Thorium
Zirconium
Radionuclklcs (pCi/g)
Ridhim-226
Radhim-228
26(26)
26(26)
26(26)
26(26)
20(26)
251
12
31.024
2.4
1.9
870
610
870
1.100
1^00
140
8.000
400
19
1.010
69.9
198.000
17.9
5.9
WW-03
WW-03
WW-03
CIM)3
WW-03
WW-03
CU-01
WW-03
ND
ND
ND
ND
ND
ND
ND
ND
CU-07
CU-08
CU-04
WW^)2(giab)
WW-02 (grab)
WW^)2 (grab)
ND
37
7.5
ND
U
1.5
ND = Not detected.
-------
Analytc
Table 6-2b
Extraction Area Subsurface Soil Contaminant Concentrations
Number of
Detections
(Number of
Samples)
Avenge
Detected
Conccuujlion
SemhroUlife Organic Compounds (ppb)
Hexachlorebenzene | 8(52)
PCBs (ppm)
Total PCBs
10(37)
Metals (ppm)
Thorium
Rxtionaciidr (pCi/r)
Radium-226
Radhira-228
55(55)
50(50)
46(46)
ND = Not detected.
279
Madumom
Detected
670
0.31^
13.0
10.2
6.0
2.01
75.0
54.2
11.43
Location of
Maximum
ParVfround LJCVC!
V2-06 (3.0)
B91-13 G.O)
V2-05 (5 .5)
V2-01 (3.0)
V2-05 (5 J>
ND
ND
7.47
1.2
1.5
-------
Table 6-3a
Fabrication Area Surface Soil Contaminant Concentrations
Analyte
Number of
Detections
(Number of
Samples) •
Average
Detected
Concentration
Maximum
Detected
Concentration
Semivolatite Organic Compounds (ppb)
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
Chrysene
Dibenzo(a,h)antriracene
Hexachforobenzene
lndeno(1 ,2.3-cd)pyrene
PCBs (ppm)
Total PCBs
Metals (ppm)
Cnrommm
Thorium
10 pi)
8(31)
9(31)
8(31)
12 (31)
2(31)
9(31)
6(31)
.320
295
265
293
339
152
859
266
1.700
1.300
1.400
1.500
2.000
250
5.100
970
Location of
Maximum
Background
Level
SS-04
SS-O4
SS-04
SS-04
SS-04
SS-O4
TF-04
SS-04
22(31)
1.3
92
SSrC2
31 (31)
31 PI)
234
3.8
2.810
13.1
FT-02 (grab)
SS-05
NO
NO
NO
NO
NO
NO
NO
NO
NO
36.5
7.5
Radionuclides (pCi/g)
•Radium-226
Radium-228
31 (31)
24(31)
1.4
1.9
5
11.6
TF-03 (grab)
CW-01
1.2
1.5
NO = Not detected.
-------
Analytc
Table 6-3b
Fabrication Area Subsurface Soil Contaminant Conccntations
Number of
Detections
(Number or
Samples)
Semivolalfle Organic Compounds (ppb)
Benzo(a)anthfaeene
Chrysenc
Hexachtonbenrene
3(44)
4(44)
7(44)
PCBs (pom)
Total PCBs
Metals (ppm)
Thorium
RadioaucEde (uCi/e)
Radium-226
Radium-228
36(50)
41(41)
39(39)
27(27)
Average
Detected
Concentration
530
558
8.800
0.619
8.2
Maximum
Detected
Concentration
Local ion of
Maximum
Background
Level
1.100
1.300
27.000
440.0
B-2 (19.5)
B-2 (19.5)
B-2 (19 3)
B92-13 Grab (12.5)
170.0
B-2 (19.5)
ND
ND
ND
NA
7.5
1.98
1.09
26.0
6.2
B-2 (19.5)
691-06(13.0)
1.2
1.5
NA = Not analyzed.
ND = Not detected.
-------
JCAlC IHfCCI
0 100 100
LBCSNO
* UONItOftlNC Kll
fOfluC* SOuOCC »»C*
Figure 6-4
Solids Area Source Location
-------
wastewater treatment plant from 1967 to 1979. These solids were the subject of a previous operable
unit (see Section 3.4.1). In addition, an additional 2,016 cubic yards of materials containing zircon
sands with elevated levels of thorium and uranium were removed from Schmidt Lake (see Section
3.4.2).
Soil sampling performed in the vicinity of the former Chlorinator Residue Pile, located north of
Schmidt Lake, revealed the presence of barium sulfate and chloride salts. Source materials from the
Chlorinator Residue Pile were removed in 1978 and barium sulfate was applied over the area to bind
remaining radium that had been found in the residual Chlorinator solids.
In 1988, approximately 44,000 cubic yards of magnesium chloride solids were removed by TWCA
from the Magnesium Resource Recovery Pile, located at the northeast corner of the LRSP. TWCA
then capped mis area with asphalt and now uses it for materials handling.
In February 1995, TWCA submitted results of samples taken following the removal of sludges from
the Lower River Solids Pond. The samples did not show any significant chemical or radionuclide
contamination. This area was also surveyed during the gamma survey (see Section 6.4).
In May 1995, TWCA submitted results of samples taken following the removal of sludges and the
additional material from Schmidt Lake. The samples did not show any significant chemical or
radionuclide contamination. This area was also surveyed during the gamma survey (see Section 6.4).
In June 1995, TWCA submitted results of subsurface samples taken from the area of the former
Chlorinator residue pile. Total radium concentrations for mis area ranged from 0.83 to 3.35
pCi/gram.
In Jury 1995, TWCA submitted the results of samples taken in the area of the magnesium resource
recovery pile. No contaminant concentrations of significance were found.
6.4 Radiological Survey (Gamma Radiation and Radon Investigation at TWCA)
In September 1994, TWCA completed a Radiological Survey of the 1) Soil Amendment Area in the
Farm Ponds Area, 2) the Extraction Area, 3) the Fabrication Area, and 4) the Solids Area. The
purpose of this study was to collect gamma radiation readings across accessible areas of the Site,
collect radon concentrations, assess potential risks posed by external gamma radiation and radon from
surface soil, and evaluate potential remedial alternatives. EPA determined that it was appropriate to
collect gamma radiation measurements for use in the risk assessment, rather than calculating potential
gamma exposure from radium concentrations, because a survey would provide more data. Attempts
to collect radon data were not successful, and therefore radon concentrations were modelled from
radium data. Subsurface gamma radiation levels were not measured. In the Human Health Risk
Assessment, risks from .subsurface radionuclides were calculated using radium data (see Section 7.1).
During the investigation, approximately 2,280 surface gamma radiation measurements were taken in
71 on-site areas.
31
-------
6.4.1 Gamma Radiation Survey
6.4.1.1 Background Contaminant Levels
Background levels of gamma radiation were obtained for the Main Plant from property near the Site
not directly impacted by TWCA operations. The background level for the Main Plant was 10.5
prem/hour. For the Soil Amendment Area, a reference level was obtained from an adjacent
agricultural field not impacted by the application of the lime solids spread on the Soil Amendment
Area. The term "reference level" reflects the fact that agricultural areas already have an increase in
gamma radiation levels over background resulting from radioactive elements in fertilizers. The
reference gamma radiation level was 12.5 prem/hour.
6.4.1.2 Main Plant
The results of the gamma survey on the TWCA Main Plant indicated that 90% of the survey readings
were below 20.5 /irem/bour (10 prem/hour over background, a level considered differentiable from
background levels, and one half of the next increment evaluated, see Section 8.3.3), and 95% were
below 30 /xrera/hour (this level is 20 prem/hour over background, a level used for screening areas
requiring remediation in the Uranium Mill Tailings Radiation Control Action of 1978, see Section
8.1). A summary of gamma radiation data for the Main Plant is shown in Table 6-4. It should be
noted mat some data are higher man the average value for the areas. The average values are
meaningful for risk assessment purposes because die risk assessment assumes that exposure takes
place in all parts of an area, not just at an individual reading.
Areas with significantly elevated gamma radiation levels were located on three areas of the Main
Plant (sample locations shown in parentheses): the parking lot outside of the boundary of the
Extraction Area (PL-01 and PL-02), the former sand unloading area in the Fabrication Area (OC-01),
and Schmidt Lake (SL-02) in the Solids Area (see Figures 6-Sa, b, and c). The elevated levels of
gamma radiation in these areas were hypothesized to be the results of the following Site activities:
Parking Lot:
This was the former location of the paint shop. Metal preparation for painting used black
sand for sandblasting. The sand is the probable cause of the elevated gamma radiation.
Former Sand Unloading Area:
The Site was used to unload zircon sand from railcars as a raw material for the zirconium
process. This resulted in sand being spilled from a conveyor belt onto the ground around the
unloading site. The zircon sand used in the process contained naturally occurring
radionuclides.
Schmidt Lake:
The area of elevated gamma radiation in Schmidt Lake was used as a temporary staging area
for the Schmidt Lake Excavation Project (SLEP) (see Section 3.4.2) Stockpiled material
included zircon sand that had elevated levels for gamma radiation due to naturally occurring
radionuclides.
32
-------
Table 6-4
Summary of Main Plant External Gamma Exposure Data
Page 1 of 3
Main
Plant
Subarca
CU-01
CU-03
CU-04
CU-05
CU-06
CU-07
CU-08.
CU-09
CW-01
CW-02
CW-03
CW-04
CW-05
FT-01
FT-03
FT-04
LRSP-01
LRSP-02
MF-01
MF-02
MF-03
LMF-04
i MF-05
MP-0!
Number of
Readings
12
16
12
11
15
12
13
8
20
16
7
25
35
17
9
9
200
196
8
16
16
10
8
34
Maximum
Detected
Value
14.28
10.92
14.28
16.92
8.87
12.27
10.24
10.24
26.46
14.28
8.87
8.87
8.87
20.81
10.92
10.24
15.61
23.35
9.56
9.56
9.56
10.24
10.92
8.87
Minimum
Detected
Value
8.19
6.11
8.19
7.50
4.71
5.41
4.71
4.71
6.11
6.11
6.11
4.01
4.71
6.80
8.19
7.50
4.71
4.71
7.50
6.80
6.11
6.80
6.80
4.71
Arithmetic
Mean
10.06
8.01
10.63
9.48
7.03
8.41
7.86
7.83
9.68
9.29
7.49
5.97
7.06
11.09
8.80
8.57
10.21
11.21
8.10
8.49
8.31
•8.32
9.04
6.88
Median
9.56
7.50
9.90
8.19
7.50
8.19
7.50
8.53
7.50
8.87
7.50
6.11
7.50
9.56
8.19
8.19
10.24
11.60
7.84
8.19
8.19
8.19
8.87
6.11
Standard
Deviation
1.90
1.58
1.81
2.90
1.28
1.61
1.90
2.40
5.47
2.53
1.13
1.15
1.34
3.63
0.93
0.85
2.59
3.59
0.77
0.8'3
0.92
1.25
1.41
1.03
Number of
readings
>20.S
/jrem/hr
2
1
'
2
Number of
readings
>30.S
/Jrem/hr
Number
readings
>S7 ^irem/hr
.
-------
Table (5-4
Summary of Main Plant External Gamma Exposure Data
Page 2 of 3
Main
Plant
Subarca
MP-03
MP-04
MP-05
MP-06
NW-01
NW-02
NW-03
NW-04
NW-05
OC-01
PL-01
PL-02
SL-01
SL-02
SS-01
1 SS-02
SS-03
SS-04
SS-05
ST-01
ST-02
ST-03
ST-04
ST-05
TF-01
Number of
Readings
30
18
16
15
II
II
II
5
9
97
122
150
85
92
21
6
6
12
18
16
15
12
9
11
21
Maximum
Detected
Value
10.92
8.87
10.24
10.24
10.92
9.56
9.56
9.56
9.56
80.17
41.06
43.78
25.22
41.61
10.24
12.95
11.60
16.27
22.08
11.60
7.50
10.92
9.56
8.19
11.60
Minimum
Detected
Value
7.50
5.41
4.71
7.50
6.80
6.80
6.11
6.80
6.11
6.80
5.41
4.71
4.71
6.80
4.01
7.50
6.11
7.50
6.11
6.11
4.71
4.71
4.71
4.71
4.71
Arithmetic
Mean
8.83
7.15
7.23
8.87
8.68
8.56
7.93
8.05
8.11
26.24
14.99
23.94
12.76
13.79
7.29
9.32
8.87
11.13
13.18
8.01
5.78
7.43
6.56
6.17
7.62
Median
8.53
7.50 .
7.50
8.87
8.87
8.87
8.19
8.19
8.19
25.08
13.28
21.45
12.95
12.27
7.50
8.87
8.87
10.24
12.27
7.50
5.41
6.80
6.80
6.11
7.50
Standard
Deviation
0.84
1.07
1.45
0.90
1.11
0.94 J
0.99
1.23
1.22
17.33
7.68
11.14
3.90
6.20
1.72
2.05
1.74
2.97
4.7,6
1.49
0.91
2.29
1.77
0.96
1.84
Number of
readings
>20.5
/jrcm/hr
54
21
80
I
7
2
Number of
readings
>30.5
/jrcm/hr
35
9
45
5
Number
readings
>57 ^rcm/lir
9
-------
Table 6-4
Summary of Main Plant External Gamma Exposure Data
Page 3 of 3
Main
Plant
Subarca
TF-02
TF-04
7F-05
WW-01
WW-03
WW-04
WW-05
WW-06
WW-01
Number of
Readings
27
31
23
9
7
12
27
24
17
Maximum
Detected
Value
11.60
14.28
11.60
11.60
9.56
10.92
8.87
9.56
10.92
Minimum
Detected
Value
6.11
6.11
6.11
7.50
5.41
4.71
4.71
4.71
5.41
Arithmetic
Mean
8.97
9.94
8.21
8.87
7.29
7.26
6.90
6.51
7.41
Median
8.87
10.24
7.50
8.87
8.19
7.15
6.80
6.80
7.50
Standard
Deviation
1.70
2.63
1.30
1.28
1.63
1.70
1.14
1.36
1.56
Number of
readings
>20.5
/u-em/hr
Number of
readings
>30.5
prem/hr
Number
readings
>S7 ^rcm/hr
-
.
-------
FPL o7l
LT U
20.00-
LEGEND
- STREAM BOUNDARY
- TOPOGRAPHICAL LINE
DIRT ROAD
EXISTING FENCE
GAMMA EXPOSURE
SURVEY SUBAREA
SURVEY GRID
LOCATIONS
COORDINATES
AND GAMMA
MEASUREMENTS
. EXTERNAL GAMMA
ISOfiAOS
5n
IB
1
EXTRACTION
AREA /
BOUNDARY
Figure 6-5a
i Gamma Survey Results
Parking Lot Area
-------
_ .. —< STREAM BOUNDARY
TOPOGRAPHICAL LINC
. . 0"RT ROAD
EXISTING FENCE
for oil GAMMA EXPOSURE
L?^r _J SU*VEY SUBAREA
" "-'^--N SURVEY GRID
LOCATIONS.
COORDINATES
'V. AND GAMMA
MEASUREMENTS
(ufem/hr) •
EXTERNAL GAMMA
I SOS ADS
Figure 6-5b
Gamma Survey Results
Former Sand Unloading Area
-------
SCALE IN rtCT
0 » 90
IfOEND
— STREAM BOUNDARY
-^ TOPOGRAPHICAL UNC
- OtRTROAO
— [XISTINO FCMCC
-WL-Bf SURVEY ««>
LOCATIONS.
COORDINATES
AND CAUUA
MEASUREMENTS
CXTCRNAL OAUMA
ISOAAOS
f
Figure 6-5c
Gamma Survey Results
Schmidt Lake
N v m \ \ v\ \\ \ .
-------
6.4.1.3 Soil Amendment Area.
The results of data from the Soil Amendment Area indicate that approximately 94 percent of the Soil
Amendment Area survey readings were below 22.5 firem/hour (10 ^rem/hour over reference levels).
None exceeded reference levels plus 20 /irem/hour. A summary of the results is shown in Table 6-5.
Results are shown in Figure 6-6.
6.4.2 Calculated Radon Levels in Future Buildings.
Potential future indoor radon concentrations were modelled from known soil concentrations of the .
parent isotope radium-226. The methodology was obtained from Diffuse NORM WASTES: Waste
Characterization and Preliminary Risk Assessment. Office of Radiation and Indoor Air. RAE-9232/1-
2. Volume I. Appendix D Risk Assessment Methodology. Sections 1.2.1 and 1.2.4. (USEPA 1993).
This approach was taken after an attempt to collect radon measurements was unsuccessful.
The model used the following equation:
CR,, = [(CRlxSDxE)/(HxRQ] x (AxDfJw x
where:
Cg,, = Indoor radon concentration (pCi/m3)
CR, = Soil radium-226 concentration (pCi/g)
SD = Soil density (g/m3)
E = Radon emanation coefficient (unitless)
H = Height of a standard room (m)
RC = Room air changes per year
A = Radon decay constant (yr*1)
Df, = Radon diffusion coefficient through soil
(mVyr)
Dff = Radon diffusion coefficient through foundation
(mVyr)
Th = Thickness of building foundation (m)
Table 6-6 shows the values of the parameters used in the model.
Radon, which emanates from radium-226 in the surface soil, is assumed to enter a building through
the concrete floor foundation. The building is assumed to be built on top of the soil where radium
concentrations were measured.
The model was applied to all surface soil radium data. Results where modelling of
radon in future buildings exceeds background concentrations are shown in Table 6-7 for the Main
Plant and Table 6-8 for the Soil Amendment Area. The areas referenced are shown on Figures 6-3a,
b and c.
39
-------
Table 6-5
Summary or Soil Amendment Area External Gamma Exposure-Dnta
SAA
Subarea
3A-01
SA-02
SA-03
SA-04
SA-05
SA-06
SA-07
SA-08
SA-09
SA-10
SA-11
SA-12
SA-13
Number of
Readings
15
15
15
15
15
15
15
15
15
15
15
15
10
Maximum
Detected
Value
22.08
20.81
23.98
23.35
27.08
23.98
18.23
25.84
16.92
20.81
20.17
22.08
22.72
Minimum
Detected
Value
9.56
8.87
10.24
11.60
11.60
12.95 .
10.24
10.92
7.50
8.87
8.87
11.60
8.87
Arithmetic
Mean
14.72
14.81
15.91
18.1
16.70 .
18.41
15.20
18.78
13.63
13.13
13.26
16.19
17.01
Median
14.28
15.61
14.95
. 18.88
15.61
16.92
15.61
19.53
15.61
12.95
12.95
15.61
16.60
Standard
Deviation
4.33
4.05
4.25
3.54
4.23
3.56
2.13
4.40
3.25
3.67
3.81
3.52
4.20
Number >20.S
(/u-cm/hr)
2
1
2
3
2
1
Number >30.5
(/a-cm/hr)
Number >57
(ffl-cin/hr)
-------
~\ I __ ff •
' 1 ' -__-
C*«"* EXPOSURE
SURVEY Z5-ACRE SU9*RE*
SURVEY C*0
LOCATIONS.
COORDINATES
AflD GAUUA
MEASUREMENTS
Figure 6-6
Gamma Survey Results
Soil Amendment Area
-------
Table 6-6
Parameters for Radon Model
Model Parameters
Radium-226 concentration (pCi/g)
Soil Density (g/cm3)
Radon Emanation Coefficient (unhless)
Height of Standard Room (m)
Room Air Changes per Year
Radon Decay Constant (yr"1)
Radon Diffusion Coefficient Through Soil (nr/yr)
Radon Diffusion Coefficient Through Building Foundation
(m2/yr)
Thickness of Building Foundation (m)
Parameter Value
From Phase
2 RI
1.29
0.55
2.3
4,400
66
22
3
0.15
-------
Table 6-7
Potential Radon Concentrations in Future Buildings
Main Plant Subarcas
Main Plant
Subarea
ST-01
ST-02
WW-01
CW-01
SS-02
SS-05
SS-04
CU-03
CU-04
MP-05
NW-03
WW-03
CU-05
cw-02
MP-06
CU-01
SS-03
TF-04
WW-07
CU-02
NW-01
Radium-226
Concentration '
(pCi/g)
8.8
6.19
5.3
3.6
3.5
3.5
2.8
2.3
2.3
1.9
1.9
1.9
1.7
1.7
1.5
1.4
1.4
1.4
1.4
1.3
1.3
Estimated Radon
Concentration b
(pCif\)
11.63
8.18
7.01
4.76
4.63
4.63
3.70
3.04
3.04
2.51
2.51
2.51
• 2.25
2J5
1.98
1.85
1.85
1.85
1.85
1.72
1.72
Background Areas
BS-01
BS-02
BS-03
BS-04
BS-05
1
1
1
1.2
1
1.32
1.32
1.32
1.59
1.32
a. Surface soil radium-226 concentrations measured during the KI.
b. Radon concentrations modeled from surface soil radium-226.
-------
Table 6-8
Potential Radon Concentrations in Future Buildings
Soil Amendment Area
Soil
Amendment
Area
Subarea
SA-01
SA-02
SA-04
SA-05
SA-06
Radium-226
Concentration a
(pCi/g)
4.4
8
6.1
1.4
4.7
Estimated Radon
Concentration b
(pCi/1)
5.82
10.57
8.06
1.85
6.21
Background Areas
BS-01
BS-02
BS-03
BS-04
BS-05
1
1
1
1.2
1
1.32
1.32
1.32
1.59
1.32
a. Surface soil radium-226 concentrations measured during the RI.
b. Radon concentrations modeled from surface soil radium-226.
-------
7.0 SUMMARY OF SITE RISKS
CERCLA response actions at the TWCA Site as described in this ROD are intended to protect human
health and the environment from risks related to current and potential exposure to hazardous .
substances at the Site.
To assess the risk posed by Site contamination, a Baseline Risk Assessment was completed by CH2M
Hill on behalf of Teledyne Wan Chang Albany, as part of the TWCA RI/FS. The Baseline Risk
Assessment evaluated human health risks from exposure to chemically contaminated groundwater,
surface water, and surface and subsurface soil. In addition, as part of the Radiological Survey
conducted by TWCA, risks associated with gamma radiation and radon, the result of radium
contamination in the Site soil, were also evaluated.
This ROD only addresses risks associated with contaminants in surface and subsurface soil in the
areas investigated during the RI/FS. Information on groundwater and surface water may be found in
the Record of Decision for Final Remedial Action of Groundwater and Sediments Operable Unit,
Teledyne Wah Chang Albany Superfund Site, June 10, 1994.
7.1 Human Health Risks
7.1.1 Approach to Human Health Risk Assessment for Chemicals and Radionuclides
Section 7.1 describes EPA's standard risk assessment methodology. This was the methodology used
for calculating risks associated with exposure to chemicals in surface and subsurface soil, risks from
exposure to radionuclides in subsurface soil (including gamma exposure), and risks from exposure to
radionuclides excluding gamma radiation and radon in surface soils. An alternative methodology was
used to calculate risks associated with exposure to external gamma radiation from surface soils, and
from inhalation of radon. This approach is described in Section 7.2. EPA determined that the
alternative methodology was appropriate given the data collected.
TWCA is an active operating facility and is expected to remain so in the foreseeable future. The
percentage of time that workers at an operating facility would spend hi a potentially contaminated area
is generally less than if the Site were used for residential purposes. Therefore, for purposes of
characterizing human health risks on the plant site, the RI/FS used an approach that is less
conservative than if the TWCA property were used for residential purposes. This less conservative
approach assumed that only workers would be exposed to risks from contaminants at the plant site.
Residential exposure may be higher than worker exposure because residential exposure is likely to be
for as much as 24 hours per day, rather than 8 hours per work day for worker exposure.
In an attempt to realistically estimate potential human health risks at the TWCA Site, based on
information presented in the RI, risks were calculated on a sample-specific basis. Summation of risks
at this Site would not have presented a meaningful approach because of the varied contaminant source
areas caused by the large and complex chemical and manufacturing processes at the TWCA facility.
In these circumstances, the sample-specific approach allows more accurate delineation of risks from
specific contaminant source areas. This approach also enables retention of information on the
geographic distribution of risk throughout the study area. The sample-specific approach to calculating
risk has also provided information on the spatial discreetness and concentration of risk which was
45
-------
readily visualized by mapping risks. Tne s^r-ple-Sj^cific risk were used to distinguish areas that
potentially exceed target risk levels from areas where exposure to contaminants results in calculated
risk levels below EPA's acceptable risk range (see Figures 6-3 a, b, and c for surface soil sample
locations).
For contaminants at the TWCA Site, the calculation of risk involved a 4-step process which included
the identification of contaminants of concern, an assessment of contaminant toxicity, an exposure
assessment of the population at risk, and a characterization of the magnitude of risk. Sections 7.1.2
through 7.1.4 cover the steps taken for chemical and radionuclide risks at the Site. Risks associated
with exposure to gamma radiation and radon are covered in Section 7.2.
7.1.2 Chemicals of Concern
The chemicals of concern were selected based on: 1) the concentration of the chemical exceeding
naturally occurring levels, (2) there being EPA-derived slope factors or reference doses available for
the chemical, and (3) the maximum detected concentration exceeding a conservative health-based
screening concentration. For surface or subsurface soils, chemicals were eliminated from
consideration if the maximum detected concentration and protective screening level exposure
assumptions resulted in a risk less than or equal to the one in ten million cancer risk value, or less
than or equal to 0.1 hazard quotient for noncancer effects using the industrial scenario for the Main
Plant and the residential scenario for the Farm Ponds Area (see Section 7.1.4). Table 7-1 provides a
list of the contaminants of concern at the Site.
Because of the presence of radium in soils, risks from exposure to gamma radiation and radon were
considered to be important for consideration. The Radiological Survey performed after the
completion of the other portions of the RI/FS investigated the presence of surface gamma radiation
and radon and calculated risks from exposure to these radium daughter products. Risks from
exposure to surface gamma radiation and radon are discussed in Section 7.2.
7.1.3 Toxicity Assessment
The Baseline Human Health Evaluation provides toxicity information for the chemicals
of concern. Generally, cancer risks are calculated using toxicity factors known as slope factors (SFs),
while noncancer risks rely on reference doses (RfDs).
EPA has developed SFs for estimating excess lifetime cancer risks associated with exposure to
potential chemical carcinogens. SFs for chemical intake (ingestion or inhalation) are expressed in
units of (mg/kg-day)"1 and are multiplied by the estimated intake of a potential carcinogen, in mg/kg-
day, to provide an upper-bound estimate of the excess lifetime cancer risk associated with exposure at
that intake level. The term "upper bound" reflects the conservative estimate of the risks calculated
from the SFs. Use of this approach makes it highly unlikely that the actual cancer risk would be
underestimated. SFs for individual chemicals are derived from the results of human epidemiological
studies, or chronic animal bioassay data, to which mathematical extrapolation from high to low dose,
and from animal to human dose, have been applied.
RfDs have been developed by EPA to indicate the potential for adverse health effects from exposure
to chemicals exhibiting noncarcinogenic effects. RfDs which are expressed in units of mg/kg-day, are
estimates of lifetime daily exposure for humans, including sensitive subpopulations likely to be
46
-------
Table 7-1
Chemicals of Concern and Selection Criteria
Chemical
Surface Soils
Farm Ponds
Plant Site
Subsurface
Soils
VOLATILE ORGANIC COMPOUNDS 3
SEMIVOLATILE ORGANIC COMPOUNDS
Benzo(a)an(hracene
Benzo(a)pyrene
Benzo(b)nuoranthene
Benzo(k)fluoranthene
Chrysene
Dibenz(a,h)anthracene
HexachJoro benzene
Indeno( 1 ,2,3-cd)pyrene
ND
ND
ND
ND
ND
ND
c
ND
d
c
d
d
d
d
c
d
d
g
ND
ND
d
ND
c
ND
PCBs
Total Aroclon
c
c
METALS f
Chromium (total)
Thorium
Zirconium
Radionudides
Radium 226
Radium 228
g
c
S
e
e
c
c
b
c
g
c
g
e
e
e
e
ND = Not detected.
a. Volatile Organic Compounds not analyzed for in surface soil, in subsurface soil
maximum values were below risk based concentrations.
b. Selected based on having a reference dose value.
c. Selected based on having a cancer slope factor.
d. Selected based on being a carcinogenic PAH and slope factor based on
.benzo
-------
without risk of adverse effect, estimated intakes of contaminatis of concern from environmental
media (e.g., the amount of a contaminant of concern ingested from incidental contact with
contaminated soil) can be compared to the RfD. RfDs for individual chemicals are derived from
.human epidemiological studies or animal studies to which uncertainty factors have been applied.
The Baseline Human Health Evaluation relied on oral and inhalation SFs and ~RfDs. The toxicity
factors shown in Table 7-2 were drawn from the Integrated Risk Information System (IRIS) or, if no
IRIS values were available, from the Health Effects Assessment Summary Tables (HEAST).
7.1.4 Exposure Assessment
The exposure assessment identified potential pathways for contaminants of concern to reach the
exposed population. Exposure assumptions were based primarily on EPA regional and national
guidance, including EPA Superfund Standard Default Exposure Factors, except where tailored to meet
specific Site conditions. Current Site use is industrial, except for the Soil Amendment Area (located
within the Farm Ponds Remedial Sector) which is currently being used for agricultural purposes. The
Baseline Human Health Evaluation evaluates exposure to current and future workers on the plant site,
and to potential future residents in the Farm Ponds Area (a conservative approach for this area). EPA
further supplemented the evaluation in the Farm Ponds Area by evaluating an agricultural worker
(farm worker) scenario in the Soil Amendment Area of the Farm Ponds Area.
Exposures to contaminants in surface soils could occur via inadvertent ingestion, skin contact, or by
inhaling dusts and vapors. The frequency, duration, extent, and route of
exposure to surface soils would depend on the particular activity of the receptor and location of the
activity. In the Baseline Human Health Evaluation, incidental ingestion exposures were estimated for
current or future workers contacting surface soil during regular working hours. Risks from skin
contact with soils were not quantified because information is not available on the efficiency of
chemical absorption from soil across the skin, and no toxicity values exist for this exposure route.
Risks from inhalation were evaluated, found to not be a significant risk driver, and are not included
in the risk calculations.
Workers may be exposed to chemicals in subsurface soils during excavations and/or trenching to
repair or place utility lines or pipes. Workers coming into contact with chemicals in subsurface soils
may become exposed through incidental ingestion, skin contact, inhalation of vapors, or external
exposure to gamma radiation. Exposures under this scenario would generally be infrequent. The risk
assessment evaluated risks from ingestion of chemicals and radionuclides, and from exposure to
gamma radiation. Risks from skin contact were not evaluated for the reasons discussed above. Risks
from inhalation were not evaluated because excavation trenches would likely be damp and protected
from wind, therefore dusts would generally not be available for inhalation. The exposure frequency
(i.e., days per year exposed) and the exposure duration (i.e., total number of years exposed) were
based on TWCA Site specific employee practice information provided to EPA by TWCA.
Exposure point concentrations for the TWCA Site Baseline Human Health Evaluation were derived in
a manner consistent with the EPA guidance to evaluate Reasonable Maximum Exposures (RMEs).
The RME is defined as the highest exposure that is reasonably expected to occur at a Site. In
addition the Baseline Human Health Evaluation incorporates information that incorporates both the
48
-------
Table 7-2 •
Toxicity Factors
CARCINOGENS
COMPOUND
Areenic
Benzene
Chloroform
Chromium VI
1,2-Diclilorethane
1, l-t>ichloroethene
Hexachlorobenzene
1,1,2, 2-Tetrachloroothane
Tatrachloroetherie
Trichloroethylene
Vinyl Chloride
Benzo(a) pyrene
Be nzo( a) anthracene
Benzo(b) f luoranthene
Benzo(k) fluoranthene
Chryeene
Dlbenz ( a, h) anthracene
lndeno( 1 , 2, 3-cd)pvrene
Polychlorlnated biphenyls
Slope Factor
Oral
2.00E+00
2.90E-02
6.10E-03
9.10E-02
6.00E-01
1.60E+00
2.00E-01
S.10E-02
1.10E-02
1.90E+00
7 . 30E+00
«
•
*
*
*
• t '_
7.70E+00
Sourco
IRIS
IRIS
IRIS
IRIS
IRIS .
IRIS
IRIS
HEAST
HEAST
HEAST
IRIS
*
*
*
*
*
* •
IRIS
Unit Risk
Inhalntlon
4.30E-01
8.30E-06
2.30E-05
1/20E-02
2.60E-05
5.00E-05
4.60E-04
5.80E-05
5.20E-07
1.70E-06
8.40E-05
1.70E-03
A
*
*
4
*
*
Source
IRIS
IRIS
IRIS
IRIS
IRIS
IRIS
IRIS
IRIS
HEAST
HEAST
HEAST
HEAST
»
*
«
•
*
A
v.'olqh; of Evidence
Oral
:. -.halation
A A
A I A
82 32
B2
C
B2
C
B2
82
A
B2
n
32
C
B2
B2
92
B2
A
E2
• •
•
*
•
•
.
*
i
* . •
i
• •
B2
Slope factor, unite - risk per milligram per kilogram of body weight per day {.(mg/kg-day)-!}
Unit, Risk, units - risk per microgram per cubic moter, {(ug/m3)-l)
* Indicates that risks were considered equivalent to Benzo(a)pyrene
i
IRIS - Integrated Risk Information System, USEPA, 1992
flEAST -Health Effects Assessment Summary tables, Annual Summary, USEPA, 1992
-------
Table 7-2 (cont.)
Toxicity Factors
NON-CARCINOGENS
COMPOUND
Acetone
Chloroform
1, 1-Dichloroethane
lfl-Dichloroethene
ciBlA2-Dichloroethene
Methyl Isobuty Ike tone
1,1, 1-Trlchloroe thane
1, 1,2-Trlchloroe thane
Ble(2-
ethylhexyl)Phthalate
Hexachlorobanze.ne
Antimony
Arsenic
Barium
Cadmium
Chromium (total)
Copper
Magnesium
Manqaneae
Mercury
Nickel
Thallium
Uranium
Zinc
REFERENCE DOSE
Oral
l.OOE-01
1 .OOE-02
l.OOE-01
9.00E-03
1. OOE-02
2.00E-.02
9. OOE-02
4.00E-03
2. OOE-02
8.00E-04
4.00E-04
3.00E-04
7. OOE-02
5.00E-04
l.OOE+00
3.70E-02 -
9.70E+00
l.OOE-01
3.00E-04
2. OOE-02
7.00E-05
3.00E-03
2.00E-01
Source
IRIS
IRIS
HEAST
IRIS
HEAST
IRIS
KEAST
IRIS
IRIS
IRIS
IRIS
IRIS
IRIS
IRIS
IRIS
HEAST
ECAO
IRIS
HEAST
IRIS
HEAST
IRIS .
HEAST '
UF/MF
1,000
1,000
1,000
1,000
3,000
1,000
1,000
1,000
1,000
100
1,000
3
3
10
500
NR
1,000
1
1,000
100
3,000
1,000
10
Inhalation
NA
NA
5.00E-01
NA
NA
NA
l.OOE-t-00
5.00E-04
4.00E-04
3.00E-04
Source
• HEAST
. HEAST
HEAST
i
IRIS
HEAST
.
UF/MF
1,000
1,000
1,000
300
30
CONFIDENCE
LEVEL
Oral/
Inhalation
Low
Mod
Hod
Hod
Med
Low
Mod
Low
Hod/Med
Med
SYSTEM .EFFECTED
Liver 6 Kidney
Liver
Kidney
Liver
Blood
Liver Enzyme
Liver
Clinical, chemistry
Liver
Liver
Clinical Chemistry
Skin
31ood, Fetus
Kidnev
Mot Reported
CI Tract
GI Tract
CNS, Respiratory
Kidnev, Nervoue
Bodv Weight
Clinical Chemistry
Kidney
Blood
-------
Table 7-2 (cont.)
Toxicity Factors
NON-CAR C IMOGENS
COMPOUND
Zirconium
Ammonia
Fluoride
Nitrate
REFERENCE DOSE
Oral
3.00E+00
6.00E-02
6.00E-02
1.60E+00
Source
ECAO
HEAST
IRIS
IRIS
UF/MF
1,000
1
1
1
Inhalation
Source
UF/MF
CONFIDENCE
LEVEL .
Oral/
Inhalation
High
Kiqh
SYSTEM EfFECTED
No Effect Level-
Taste
Teeth
Blood
Reference Doee, units - milligrams per ktlograro of body weight per day (mg/kg/day)
UF - Uncertainty factor
MF - Modifying Factor
NA - Not available
NR - Not Reoorted
IRIS - Integrated Risk Information System, USEPA, 1992
HEAST - Health Effects Aseeosmont Summary Tables, Annual Summary, USEPA, 1992
ECAO -'Environmental Criteria and Aeeeosment Office, USEPA, Cincinnati, 1992
RAD IONUCL IDES
COMPOUNO
Radlum-226D
Radium-228D
Thorium-228
Thorium-230
Thorium-232
SLOPE FACTOR
Inqeetion
1.20E-10
l.OOE-10
5.50E-11
1.30E-11
1.20E-11
Inhalation
3.00E-09
6.90E-10
7.80E-08
2.90E-08
2.00E-08
SOURCE
HEAST
HEAST
HEAST
HEAST
. HEAST
WEIGHT OF EVIDENCE
A
A
A
A
A
0 - Risks from decay products also included
Slope Factor, unite - risk per unit picocurie intake or exposure (risk/pCil
HEAST - Health Effects Assessment Summary Tables, Annual Summary, USEPA, 1992
-------
average and the high-end RME portions of the risk distribution. Presentation of the plausible range
of risk allow risk management decisions to incorporate the relative uncertainty in the risk estimates.
The average case exposure assumptions largely represent the 50th percentile values within a normally
distributed population.
The exposure assumptions used to estimate potential RME and average case exposures to chemicals of
concern in soils at the TWCA Site are summarized in Tables 7-3a, b, and c.
7.1.5 Risk Characterization
For carcinogens, risks are estimated as the incremental probability of an individual developing cancer
over a lifetime as a result of exposure to the carcinogen. Excess lifetime cancer risk is calculated by
multiplying the chemical specific SF (see "Toxicity Assessment" above) by the "chronic daily intake"
for that chemical developed using the exposure assumptions. These risks are probabilities generally
expressed in scientific notation (e.g. 1 x 1C4). An excess lifetime cancer of 1 x 10"4 means that an
individual has a 1 in 10,000 chance of developing cancer as a result of site-related exposure to a
carcinogen under the specific exposure conditions .assumed.
The potential risk for non-carcinogenic effects are evaluated by comparing an exposure level over a
specified time period (e.g., lifetime) with a chemical specific reference dose (see "Toxicity
Assessment" above) derived for a similar exposure period. Hazard quotients are calculated by
dividing the chronic daily intake by the specific RfD. By adding the hazard quotients for all
contaminants of concern, the hazard index (HI) can be generated.
The RME provides a conservative but realistic exposure in considering remedial action at a Superfund
site. Based on the RME, when the excess lifetime cancer risk estimates are below 1 x 10"* (1 in
1,000,000), or when the noncancer HI is less than 1, EPA generally considers the potential human
health risks to be below levels of concern. Remedial action is generally warranted when excess
lifetime cancer risks (hereafter excess cancer risks) exceed 1 x 10-4 or the hazard index exceeds 1.
Between 1 x 10"6 and 1 x 10"4, cleanup may or may not be selected, depending on individual site
conditions including human health and ecological concerns.
The potential human health risks at the TWCA Site were characterized by estimating risks on a
sample-specific basis. This approach retains information on the geographic distribution of risk
throughout the study area. The sample specific risks were used to distinguish specific areas of the
TWCA Site that exceed risk-based levels.
7.1.6 Chemical and Radionuclide Risks
Tables 7-4a and b summarize the excess risks from exposure to surface and subsurface soils at the
Site. For surface soil, risks include ingestion of chemicals and radionuclides, but do not include risks
from exposure to gamma radiation and radon (see Section 7.2). Risks from exposure to subsurface
soils include ingestion of chemicals and radionuclides, and exposure to subsurface gamma radiation.
As described below, risks from exposure to chemical and radionuclide contamination (excluding
gamma radiation and radon) were generally low. For surface soils, the chemicals with the most
significant contribution to Site risks were PCBs, hexachlorobenzene, and PAHs. For subsurface soils,
52
-------
Table 7-3a
Exposure Assumptions for Subsurface Soil Pathways
Exposure Parameters
Exposed Individual
Body Weight (kg)
tngestion Rate (mg/day)
Days/year Exposed
Years Exposed
Average
. Trench Worker
70
100
24
5
RME
Trench Worker
70
480
24
5
Table 7-3b
Exposure Assumptions for Surface Soil Pathways
Exposure Parameters
Exposed Individual
Body Weight (kg)
Ingestion Rate (mg/day)
Days/year Exposed
Years Exposed •
Plant Area
Average
Worker
70
50
250
9
RME
Worker
70
50
250
25
Farm Ponds Area
Average
. Resident
70
100
275
9
RME
Resident
15(0-6yr)
70 (>6yr)
200 (0-6yr)
100 (>6yr)
350
30
Table 7-3c
Exposure Assumptions for Agricultural Pathways
Exposure Parameter
Exposed Individual .
Body Weight (kg)
Ingestion Rate (mg/day)
Days/year Exposed
Years Exposed
Average
Farm Worker
70
480
30
9
RME
Farm Worker
70
480
30
25
-------
Table 7-4a
Summary of Sample-Specific Risks for Surface Soils
Remedial Sector
Farm Ponds Area-
Residential
Chemical Risk
Radionuclide Risk
Farm Ponds Area -
Farm Worker
Chemical Risk,
Radionuclide Risk
Extraction Area
. Chemical Risk
Radionuclide Risk
Fabrication Area
Chemical Risk
Radionuclide Risk
Background
Chemical Risk - Res.
- Ind.
Radionuclide Risk - Res.
-Ind.
Hazard Index > 1.0
Average
0/14 •
NA
RME
0/14
NA
Cancer Risk 5: W
Average
0/14
0/14
RME
0/14
0/14
Cancer Risk Z 10 '
Average
0/14
0/14
RME
4/14
0/14
Cancer Risk £ 10^
Average
'4/14
0/14
RME
5/14
5/14
0/6
NA
0/26
NA
0/31
NA
0/10
0/10
NA
NA
0/6
NA
0/26
NA
0/31
NA
0/10
0/10
NA .
NA
0/6 .
0/6
0/26
0/26
0/31
0/31
0/10
0/10
0/10
0/10
0/6
0/6
0/26
0/26
0/31
0/31
3/10
0/10
0/10
0/10
0/6
0/6
0/26
0/26
0/31
. 0/31
1
1/10
0/10
0/10
0/10
0/6
0/6
3/26
0/26
3/31
0/31
9/10
4/10
0/10
0/10
1/6
0/6
9/26
0/26
7/31
0/31
9/10
5/10
0/10
0/10
4/6
0/6
13/26
1/26
13/31
0/31
10/10
10/10
0/10
0/10
Values listed are the number of surface soil samples in the remedial sector that had sample-specific noncancer hazard index
estimates exceeding 1.0, or excess lifetime cancer risk estimates of greater than or equal to IxlO"4, IxlO'5, or IxlO'4. under assumed
reasonable maximum or average case exposure conditions. Risks from radon inhalation and gamma exposure are not included.
NA = Not applicable.
-------
Table 7-4b
Summary of Sample-Specific Risks for Subsurface Soils
Remedial Sector
Farm Ponds Area"
Chemical Risk
Radionuclide Risk
Extraction Area
Chemical Risk
Radionuclide Risk
Fabrication Area
Chemical Risk
Radiocuclide Risk
Background
Chemical Risk
Radiation Risk
Hazard Index > 1.0
Average
0/18
NA
0/69
NA
0/58
NA
0/10
NA
RME
0/18
NA
0/69
NA
0/58
NA
0/10
NA
Cancer Risk a NV4
Average
0/18
0/18
0/69
4/63
0/58
1/44
0/10
0/10
RME
0/18
0/18
0/69
4/63
0/58
1/44
0/10
0/10
Cancer Risk a 10'5
Average
0/18
0/18
0/69
13/63
0/58
4/44
0/10
0/10
RME
0/18
0/18
0/69
13/63
3/58
4/44
0/10
0/10
Cancer Risk a 10*
Average
0/18
5/18
0/69
54/63
3/58
39/44
0/10
10/10
RME
0/18
5/18
2/69
54/63
7/58
39/44
5/10
10/10
Values listed are the number of subsurface soil samples in the remedial sector that had sample-specific
noncancer hazard index estimates exceeding 1.0 or excess lifetime cancer risk estimates of greater than or
equal to IxlO'4, IxlO"5, or IxlO'6, under assumed reasonable maximum' or average case exposure conditions.
NA = Not applicable.
a. Residential risks
-------
the most significant contributions to Site risks came from PCBs and radionuclides.
In the Fann Ponds Area, surface and subsurface excess risks were all less than IxlO"5 and a non-
cancer hazard index of 1 for the farm worker scenario. For residential risks, the risks were 2xlO"5 or
less, and the hazard index less than 1. In the risk assessment, risks using an industrial exposure
scenario were not calculated for the Farm Ponds Area. However, because the exposure duration for
the industrial scenario is approximately half that of the residential scenario, risks from this scenario
would be proportionally lower.
On the Main Plant, no surface soil or subsurface soil non-cancer hazard index exceeded 1. For
surface soils, some samples resulted in excess cancer risk estimates exceeding IxlO"5, but less man
IxlO"4. The excess risks were from exposure to PCBs and PAHs in subareas of the Fabrication Area.
For subsurface soils, some chemical risks in the Fabrication Area exceeded 1x10*. but were less than
IxlO"*. In the Extraction Area, a small number of samples posed a radiation risk of IxlO"1.
For subsurface PCBs and subsurface radionuclides in the Fabrication Area, and subsurface
radionuclides under the V-2 Pond in the Extraction Area, the contamination in these areas could pose
a risk greater than IxlO"4 if it were subject to the exposure assumptions for surface material.
7.2 Human Health Risks from Exposure to Surface Gamma Radiation and Inhalation
of Radon
When radionuclides decay, radiation is produced. Other unstable radioactive decay products such as
radon can result. The major pathways for human exposure from radium contamination in the soil are
the inhalation of radon, which will accumulate in buildings, and exposure to gamma radiation.
Gamma radiation is continuously emitted from soil contaminated with radionuclides. The extent of
exposure is dependent on how close one is to the source, and whether or not the source is shielded by
something which partially absorbs the gamma radiation. Gamma radiation emitted by unshielded
radium contaminated soil gives anyone standing over a contaminated area a radiation dose over the
whole body. The greater the duration and intensity of this exposure, the larger the dose, and hence
the greater the risk of adverse health effects.
The exposure pathway for radon is through inhalation. Radon has short-lived decay products which
can expose the internal tissue of the lungs to bursts of energy if they decay within the lungs.
Prolonged inhalation of air containing high concentrations of radon decay products has been shown to
increase the risk of contracting lung cancer.
When radon seeps into open spaces from radium contaminated soil, it mixes with large amounts of air
which generally dilutes the radon. However, radon decay products can accumulate to higher
concentrations in buildings built over contamination, because structures tend to trap radon.
In order to estimate excess lifetime cancer risk from the gamma exposure measurements, assumptions
were made to estimate a lifetime radiogenic dose of gamma radiation. Table 7-5 lists the exposure
assumptions used for this risk analysis for external gamma radiation exposure. For the Main Plant
areas, only an industrial scenario was considered. For the Soil Amendment Area, farm worker
(current use), industrial (most likely future use), and residential (hypothetical maximum future use)
scenarios were considered.
56
-------
Table 7-5
Exposure Assumptions for External Gamma Radiation Pathways
Exposed Individuals
Hours/Week
Outdoors
Hours/Week Indoors
Gamma Shielding
Factor Indoors
Days/Year Exposed
Years Exposed
Cancer Slope Factor
(Risk/Lifetime
Millirem)
Exposure Parameters
'Main Plant Area
Industrial
Workers
10
30
0.66
250
25
6.2xl07
Soil Amendment Area
Farm
Workers
"40
None
0.25
30
25
6.2xl07
Industrial
Workers
10
30
0.66
250
25
6.2xT07
Residents
42
126
0.20
350
30
6.2xl07
-------
The potential cancer risks from gamma radiation exposure were estimated using the following
equation from Human Health Evaluation Manual. Part B: 'Development of Risk-based Preliminary
remediation Goals". OSWER Directive 9285.7-01B (USEPA 1991):
R = CSF x ER x CF x (1-Sh) x ET x EF x ED
where:
R = Excess Lifetime Cancer Risk
CSF = Cancer Slope Factor (risk/lifetime millirem)
ER = Gamma Emission Rate (prem/hour)
CF = Unit Conversion Factor (10"3 mrem//zrem)
Sh = Gamma Shielding Factor (unitless)
ET = Exposure Time (hours/day)
EF = Exposure Frequency (days/year)
ED = Exposure Duration (years)
For this assessment an average lifetime risk of radiogenic cancer of 6.2xlO'7 per lifetime millirem was
used.
Excess cancer risks for radon inhalation were estimated from indoor radon concentrations using the
following equation from Diffuse NORM WASTES: Waste Characterization and Preliminary Risk
Assessment. Office of Radiation and Indoor Air. RAE-9232/1-2. Volume I. Appendix D Risk
Assessment Methodology. Sections 1.2.1 and 1.2.4. (USEPA 1993):
Risk = CR,, x Fr x CSF^ x ED
where:
CR,, = Indoor Radon Concentration (pCi/m3)
Fr = Fraction of Year Exposed
CSFy, = Cancer Slope Factor: Cancer risk per pCi/1
radon per year exposed (4.3x10*)
ED = Exposure Duration (years)
The indoor radon concentrations were modelled using the equation in Section 6.4.2. Table 7-6 shows
the exposure assumptions used for calculating risks from radon inhalation. For the Main Plant areas,
only an industrial scenario was considered. For the Soil Amendment Area, an industrial (most likely
future use), and residential (hypothetical maximum future use) scenarios were considered. The
agricultural scenario is not used because the increased risk associated with radon comes from the
increase in contaminant concentration inside a building.
58
-------
1 Table 7-6
1 Exposure Assumptions for Radon Inhalation Pathways
Exposure Parameters
Fraction of Year Exposed
Fraction of Time Spent Indoors
Years Exposed
Cancer Slope Factor (Risk per pCi/m3 of Radon)
Parameter
Value
Worker - 0.23
Resident - 1.0
Worker - 0.75
Resident - 0.75
Worker - 25
Resident - 30
4.3x1 0'8
-------
7.2.1 Gamma Radiation Risks
Tables 7-7a, b, c, and d show the results of the risk assessment for gamma radiation. Naturally
occurring levels of radionuclides result in significant risks from gamma radiation. Therefore, the
background risk level for the Main Plant, and the reference' risk level for the Soil Amendment Area
also need to be considered when evaluating contaminant related risks. For this reason, the tables
present total excess lifetime cancer risks (risks including background or reference levels), and
incremental excess lifetime cancer risks (risks in excess of background or reference levels). Remedial
decisions will be based on the incremental excess lifetime cancer risks (hereafter referred to as
incremental excess risks). Risks were calculated for the same sample areas as used to calculate the
chemical risks.
The highest Main Plant incremental excess risks were for the three areas with the elevated gamma
radiation levels. These areas had the following incremental excess risks above background levels: the
chemical unloading area 2.4x10^ (OC-1), the parking lot 2-lxlO4 (PL-2), and 6.9xlO5 (PL-1), and
Schmidt Lake 5.1x10"5 (SL-2) (sample locations are shown in Figures 6-3a, b, and c). The
background risk from gamma radiation exposure for the Main Plant was 1.6x10"*.
For the Soil Amendment Area, the highest incremental excess risks were 9.7xl05 for the industrial
scenario (1.9x10* reference risk); 9.1x10"* for the farm worker scenario
(3.5xlO5.reference risk); and 9.6X10"4 for the residential scenario (1.7xl03 reference risk).
7.2.2 Risks from Radon Inhalation
Estimated excess risks from modelled radon concentrations in future buildings are shown in Tables 7-
8a, b, and c. As discussed in Section 7.2.1 for gamma radiation, naturally occurring levels of
radionuclides also result in significant radon risks. Therefore, the tables present total excess lifetime
cancer risks (risks including background or reference levels), and incremental excess lifetime cancer
risks (risks in excess of background or reference levels). Risks were calculated for the same sample
areas as used to calculate the chemical risks. The highest incremental excess risks for the Main Plant
ranged to 2.5xl03. For the Soil Amendment Area, excess incremental risks ranged to 2.2xlO3 for
the industrial scenario, and to 8.4xlO3 for the residential scenario (sample locations are shown in
Figures 6-3a, b, and c).
7.3 Risk Assessment Uncertainty
The accuracy of the risk characterization depends in large part on the accuracy and representativeness
of the sampling, exposure, and lexicological data. Many assumptions are intentionally conservative
so the risk assessment will be more likely to over-estimate risk than to underestimate it.
1 As discussed in Section 6.4.1.1 a reference level is used for the Soil
Amendment Area to take into account the use of fertilizers on the agricultural
area.
60
-------
Table 7-7a
Summary of Cancer Risk Estimates for Gamma Radiatfon
Main Plant Area - Industrial Scenario
Soil Amendment
Area Sample
OC-01
PL-02
PL-01
SL-02
SS-05
SL-01
LRSP-02
SS-04
FT-01
CU-04
background
Arithmetic Mean
Gamma Exposure
Rate ^rem/hour
26.24
23.94
14.99
13.79
13.18
12.76
11.21
11.13
11.09
10.63
10.52
Excess Lifetime
Cancer Risk2
4.1E-04
3.7E-04
2.3E-04
2.1E-04
2.0E-04
2.0E-04
1.7E-04
1.7E-04
1.7E-04
1.6E-04
1.6E-04
Incremental
Excess Lifetime
Cancer Riskb
2.4E-04
2.1E-04
6.9E-05
5.1E-05
4.1E-05
3.5E-05
1.1E-05
9.4E-06
8.8E-06
1.7E-06
O.OE-00
a. Calculated as the total gamma risk including background risk.
b. Risk in excess of background risk.
-------
Table 7-7b
Summary of Cancer Risk Estimates for Gamma Radiation
Soil Amendment Area - Farm Worker Scenario
Soil Amendment
Area Sample a
Arithmetic Mean
Gamma Exposure
Rate
^rem/hour
Excess Lifetime
Cancer Risk6
Incremental
Excess Lifetime
Cancer Risk0
SA-Total
15.81
4.45E-5
9.1E-6
Reference Area
12.54
3.5E-5
O.OE+00
a. Gamma data from the whole Soil Amendment Area were aggregated for this scenario.
b. Calculated as the total gamma risk including reference risk.
c. Risk in excess of the reference risk.
-------
Table 7-7c
Summary of Cancer Risk Estimates for Gamma Radiation
Soil Amendment Area - Industrial Scenario
Soil Amendment Area
Sample *
SA-1
SA-2
SA-3
SA-4
SA-5
SA-6
SA-7
SA-8
SA-9
SA-10
SA-11
SA-12
SA-13
Reference Area
Arithmetic Mean
Gamma Exposure Rate
/irem/hour
14.72
14.81
15.91
18.15
16.7
18.41
15.20
18.78
13.63
13.13
13.26
16.19
17.01
12.54
Excess Lifetime Cancer
Risk"
2.3E-4
2.3E-4
2.5E-4
2.8E-4
2.6E-4
2.9E^t
2.4E-4
2.9E-4
2.1E-4
2.0E-4
2.1E-4
2.5E-4
2.6E-4
1.9E-4
Incremental Excess
Lifetime. Cancer Risk'
3.4E-5
3.5E-5
5.2E-5
8.7E-5
6.4E-5
9.1E-5
4.1E-5
9.7E-5
1.7E-5
9.2E-5
1.1E-5'
5.7E-5
6.9E-5
O.OE+00
a. gamma data from 2.5 acre subplots were aggregated to estimate future occupational
exposure.
b. Calculated as the total gamma risk including reference risk.
c. Risk in excess of the reference risk.
-------
Table 7-7d
Summary of Cancer Risk Estimates for Gamma Radiation
Soil Amendment Area - Residential Scenario
Soil Amendment Area
Sample '
SA-1
SA-2
SA-3
SA-4
SA-5
SA-6
SA-7
SA-8
SA-9
SA-10
SA-11
SA-12
SA-13
Reference Area
Arithmetic Mean
Gamma Exposure Rate
prcm/hour
14.72
14.81
15.91
18.15
16.70
18.41
15.20
18.78
13.63
13.13
13,26
16.19
17.01
12.54
Excess Lifetime Cancer
Risk"
2.0E-3
2.0E-3
2.1E-3
2.4E-3
2.2E-3
2.4E-3
2.0E-3
2.5E-3
1.8E-3
1.7E-3
1.8E-3
2.1E-3
2.3E-3
1.7E-3
Incremental Excess
Lifetime Cancer Risk1
2.9E-4
3.0E-4
4.5E-4
7.5E-4
5.5E-4
7.8E^
3.5E-4
8.3E-4
1.5E-4
7.9E^
9.6E-4
4.8E-4
5.9E-4
O.OE+00
a. gamma data from 2.5 acre subplots were aggregated to estimate future occupational .
exposure.
b. Calculated as the total gamma risk including reference risk.
c. Risk in excess of the reference risk.
-------
Table 7-8a
Summary of Cancer Risk Estimates for Radon Inhalation
Main Plant Subareas - Industrial Scenario
Main Plant
Subarca
ST-01
ST-02
WW-01
CW-01
SS-02
SS-05
SS-04
CU-03
CU-04
MP-05
NW-Q3
WW-03
CU-05
CW-02
MP-06
CU-01
SS-03.
TF-04
WW-07
CU-02
NW-01
Radium-226
Concentration '
(pCi/g)
8.8
6.19
5.3
3.6
3.5
3.5
2.8
2.3
2.3
1.9
1.9
1.9
1.7
1.7
1.5
1.4
1.4
1.4
1.4
1.3
1.3
Estimated Radon
Concentration b
(pC'1)
11.63
8.18
7.01
4.76
4.63
4.63
3.70
3.04
3.04
2.51
2.51
2.51
2.25
2.25
1.98
1.85
1.85
1.85
1.85
1:72
1.72
Total Excess
Lifetime
Cancer Riskc
2.9E-03
2.0E-03
1.7E-03
1.2E-03
1.1E-03
1.1E-03
9.1E-04
7.5E-04
7.5E-04
6.2E-04
6.2E-04
6.2E-04
5.5E-04
5.5E^t
4.9E-04
4.5E-O4
4.5E-04
4.5E-04
4.5E-04
4.2E-04
4.2E-04
Incremental Excess
Lifciimc
. Cancer Risk d
2.5E-03
1.6E-03
1.3E-03
7.8E-04
7.5E-04
7.5E-04
5.2E-04
3.6E-04
3.6E-04
2.3E-04
2.3E-04
2.3E-04
1.6E-04
1.6E-04
9.7E.05
6.5E-05
6.5E-05
6.5E-05
6.5E-05
3.2E-05
3.2E-05
Background Areas
BS-01
BS-02
BS-03
BS-04
BS-05
1
1
1
1.2
1
1.32
1.32
1.32
1.59
1.32
3.2E-04
3.2E-04
3.2E-04
3.9E-04
3.2E-04
_
—
...
...
...
a. Surface soil radium-226 concentrations measured during the RI.
b. Radon concentrations modeled from surface soil radium-226.
c. Calculated as the total subarea radon risk, including background risk.
d. Calculated as the subarea radon risk in excess of die background risk of 3.9x10-4.
The calculated risk at (he EPA action level of 4.0pCi/l is 9.8xlO-4for an industrial scenario.
-------
Table 7-8b
Summary of Cancer Risk Estimates for Radon Inhalation
Soil Amendment Area - Industrial Scenario
Soil
Amendment
.Area
Subarea
SA-01
SA-02
SA-04
SA-05
SA-06
Radium-226
Concentration a
(pCi/g)
4.4
8
6.1
1.4
4.7
Estimated Radon
Concentration b"
(pCi/1)
5.82
10.57
8.06
1.85
6.21
Total Excess
Lifetime
Cancer Riskc
1.4E-03
2.6E-03
2.0E-03
4.5E-04
1.5E-03
Incremental
Excess
Lifetime
Cancer Riskd
l.OE-03
2.2E-03
1.6E-03
6.5E-05
1.1E-03
Background Areas
BS-01
BS-02
BS-03
BS-04
BS-05
1
1
1
1.2
1
1.32
1.32
1.32
1.59
1.32
3.2E-04
3.2E-04
3.2E-04
3.9E-04
3.2E-04
—
—
—
—
—
a. Surface soil radium-226 concentrations measured during the RI.
b. Radon concentrations modeled from surface soil radium-226.
c. Calculated as the total subarea radon risk, including background risk.
d. Calculated as the subarea radon risk in excess of the background risk of 3.9x10-4.
The calculated risk at the EPA action level of 4.0pCi/l is 9.8xlO-4for an industrial scenario.
-------
Table 7-8c
Summary of Cancer Risk Estimates for Radon Inhalation
Soil Amendment Area - Residential Scenario
Soil
Amendment
Area
Subarea
SA-01
SA-02
SA-04
SA-05
SA-06
Radium-226
Concentration a
(pCi/g)
4.4
8
6.1
1.4
4.7
Estimated Radon
Concentration
(pCi/1)
5.82
10.57
8.06
1.85
6.21
Total Excess
Lifetime
Cancer Risk0
7.5E-03
1.4E-02
l.OE-02
2.4E-03
8.0E-03
Incremental
Excess
Lifetime
Cancer Riskd
5.5E-03
1.2E-02
8.4E-03
3.4E-04
6.0E-03
Background Areas
BS-01
BS-02
BS-03
BS-04
BS-05
1
1
1
1.2
1
' 1132
1.32
1.32
1.59
1.32
1.7E-03"
1.7E-03
1.7E-03
2.0E-03
1.7E-03
„
...
—
—
...
a. Surface soil radium-226 concentrations measured during the RI.
b. Radon concentrations modeled from surface soil radium-226.
c. Calculated as the total subarea radon risk, including background risk.
d. Calculated as the subarea radon risk in excess of the background risk of 3.9x10-4.
The calculated risk at the EPA action level of 4.0pCi/l is 5.2x10-3 for a residential scenario.
-------
The sample-specific approach used for the assessment of risks at the TWCA Site could potentially
over or under estimate risk. Much of the sampling was directed rather than random. This could lead
to higher calculated risks for suspected source areas where concentrations of chemicals exceed
average on-site levels. Since the sampling at the Site, however, was not exhaustive, under-estimation
of risk may occur as areas of higher concentration (i.e., "hot spots") may have been missed.
Uncertainty in the chemical toxiciry evaluation may overestimate risks by relying on slope factors that
describe the upper confidence limit on cancer risk for carcinogens. Some underestimation of risk may
occur due to lack of quantitative toxiciry information for some contaminants detected at the TWCA
Site. Qualitative uncertainty (over or underestimation) exists when assuming chemicals that cause
cancer in animals may also cause cancer in humans.
A source of uncertainty which could lead to underestimation of risk is that chemical concentrations in
•environmental media will remain constant over the assumed exposure period. As TWCA is an active
operating facility leaks or spill of hazardous materials from pipes and structures could pose additional
risks at the Site. In addition, as the RI was only designed to characterize contamination in areas
which were not under existing buildings and structures on the TWCA Site, it is uncertain whether
contamination which may pose further risks exists in the uncharacterized areas.
The assumption that concentrations will remain constant over the assumed exposure period may also
lead to overestimation because some compounds may degrade or disseminate over time.
7.4 Environmental Risk Characterization
To assess the environmental effects of the contaminants present at the TWCA Site, TWCA conducted
an evaluation of potentially affected terrestrial and aquatic species. The results of this Environmental
Risk Characterization, and remedial alternatives to remediate the environmental risk are covered in
the Record of Decision for Final Remedial Action of Groundwater and Sediments Operable Unit,
Teledyne Wah Chang Albany Superfund Site, June 10, 1994.
7.5 Conclusions
For exposure to chemicals and radionuclides, there were no surface or subsurface sample-specific
non-cancer hazard indices for soils which exceeded 1. A limited number of surface soil samples
resulted in excess lifetime cancer risk estimates exceeding IxlO'5, but were less than IxlO"4. Excess -
risks from exposure to gamma radiation and radon exceeded the IxKX* risk level.
Actual or threatened releases of hazardous substances from this Site, if not addressed by implementing
the response actions selected in this ROD, may present an imminent and substantial endangerment to
public health, welfare, or the environment.
7.6 Risk Management Decisions
For this ROD, EPA has determined that the industrial scenario is most appropriate for determining
the need for remedial action on the Main Plant, and the industrial and farm worker scenarios are the
most appropriate for determining the need for remedial action for the Soil Amendment Area.
68
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For the areas investigated during the RI/FS, cleanup is needed fcr suif^ce gamma radiation in certain
areas on the Main Plant and for radon on the Main Plant and the Soil Amendment Area. Cleanup is
needed because risks exceed acceptable risk levels.
Risks from exposure to chemicals and radionuclides in surface and subsurface soils are within
acceptable levels. No cleanup is required as a result of these constituents. This determination is
based on the current and expected future uses for these areas (industrial for the Main Plant,
agricultural or industrial for the Soil Amendment Area). For subsurface contamination, this
determination is based on this material remaining in place. Cleanup action will be required if any
areas are found to be a groundwater contamination source during future groundwater sampling
performed as part of the requirements of the 1994 ROD.
To address the potential risks from the Site, the following cleanup objectives were developed:
Reduce the exposure to radon that would occur in future buildings constructed on the Main
Plant and the Soil Amendment Area.
Reduce surface gamma radiation exposure to acceptable levels.
Where surface and subsurface chemical risks are acceptable based on industrial or agricultural
use, ensure that these areas are not used for other purposes, and that proper handling and
disposal of soil occurs when it is disturbed.
For areas with subsurface contamination, provide easily accessible information on the
locations of the material for TWCA plant workers, future Site purchasers, or regulatory
agencies. This includes the PCB contamination in the Fabrication Area, and the residual
radionuclide contamination in the Fabrication Area and Extraction Area.
69
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8.0 DESCRIPTION OF ALTERNATIVES
The TWCA Site was divided into two areas in order to facilitate evaluation of remedial alternatives.
These areas are the Main Plant Area and the Farm Ponds Area. In the Farm Ponds Area, the Soil
Amendment Area is the area where remediation is required. The Main Plant Area was further
subdivided into the Extraction, Fabrication, and the Solids Area. Remedial alternatives were analyzed
in detail for each area of the Site.
Estimated costs for each of the alternatives are accurate within the range of +50 percent to -30
percent. Estimated present worth costs are based on a 30-year life of the remedial alternative using a
discount rate of 5 percent.
All of the evaluated alternatives would result in contaminants remaining on Site above health-based
levels (if Site use changed). Therefore, CERCLA requires that Site conditions be reviewed at
intervals of at least every five years. If warranted by the review, additional remedial actions would
be initiated at that time.
8.1 Significant ARARs for the Remedial Actions Proposed for the Site
8.1.1 Health and Environmental Protection Standards for Uranium and Thorium Mfll
Tailings (40 CFR Part 192.12)
Portions of this regulation referred to as UMTRCA are considered relevant and appropriate to the
remedial action requirements. The regulation applies to uranium mill tailings, and is therefore not an
applicable regulation. It has been cited as relevant and appropriate hi a number of previous EPA
Records of Decision dealing with remediating risks from gamma radiation2. The discussion below
describes how this regulation will be applied to determine remedial requirements.
192.12 provides the following standards3:
(a) The concentration of radium-226 in land averaged over
any area of 100 square meters shall not exceed the background
level by more than-
see among others:
Monticello Mill Tailings, UT, 1990 (EPA/ROD/RO8-90/024
Glen Ridge Radium, NY, 1989 (EPA/ROD/R02-89/079), and
1990 (EPA/ROD/R02-90/125)
Radium Chemical, NY, 1990 (EPA/ROD/R02-90/103)
Denver Radium (OU 8), CO, 1992, (EPA/ROD/RO-8-92/063)
3 For radon gas at 50% equilibrium, an annual average exposure of 0.02
Working Level (WL) of radon decay products corresponds to an annual average
exposure to a concentration of 4.0 pCi/liter of air. For this ROD this
conversion will be used. In addition, a microroentgens per hour will be
considered the equivalent of a /irem/hour (microrem per hour) .
70
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(J) 5 pG/g, averaged over the first 15 cm of soil below the surface, and
(2) 15 pCi/g, averaged over 15 cm thick layers of soil more than 15 cm below the surface.
(b) In any occupied or habitable building-
(1) The objective of remedial action shall be, and reasonable effort shall be made to achieve,
an annual average (or equivalent) radon decay product concentration (including background)
not to exceed 0.02 WL. In any case, the radon decay product concentration (including
background) shall not exceed 0.03 WL, and
(2) The level of gamma radiation shall not exceed the background level by more than 20
microroentgens per hour.
At the TWCA Site, the standard of 5 pCi/gram, averaged over the first 15 cm of soil below the
surface, and 15 pCi/gram radium-226, averaged over 15 cm thick layers of soil more than 15 cm
below the surface is not applicable because the material at TWCA is from a different source than that
covered in 40 CFR 192. At this site, it is also not a relevant and appropriate requirement based on
situational and risk differences between TWCA and sites regulated under UMTRCA. The radium
contaminated material at TWCA differs from uranium mill tailings in that it has a lower maximum
radium concentration. The anticipated uses of the TWCA Site also differ from those contemplated in
UMTRCA. Because of these and other differences, areas of TWCA exceeding the limits for radium-
226 in UMTRCA did not exceed risk based levels for ingestion of radionuclides, or exposure to
gamma radiation. However, the soil activity standards provided in UMTRCA are higher than those
which would be protective for addressing risks posed by exposure to indoor radon.
The gamma radiation exposure level of 20 pRoentgens (20 prem/hour in this ROD) has been
evaluated as a potential cleanup level. Gamma radiation at or near this level has been used to
include properties for remedial action in implementing UMTRCA at properties which may have
received mill tailings. The averaging of the concentration over 100 meters square will also be used.
The indoor radon concentration of 4 pCi/liter (convened from 0.02 WL, see footnote 3) is the
selected action level. Action will be required where measured levels, or appropriate modelling
predicting radon concentration in future buildings, exceeds this level. This concentration will be used
as the industrial action level for the TWCA Site. Because the remedial actions were developed for an
industrial scenario, a residential action level for radon is not being provided in this ROD.
Using the model in Section 6.4.2, a soil radium-226 concentration greater than 3 pCi/gram could
result in a radon concentration in future buildings exceeding the 4 pCi/liter radon action level. This
standard will be applied to surface and subsurface soil to designate areas requiring action for radon.
8.1.2 Oregon Statutes and Regulations
Oregon Environmental Cleanup Law, Oregon Revised Statute (ORS) Chapter 465; Oregon
Environmental Cleanup Rules, Oregon Administrative Rule (OAR) Chapter 340, Division 122,
Sections 10 through 110. These regulations are applicable for Site soils. They require cleanup to
background or the lowest feasible level.
71
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Energy Conservation, Oregon Revised Statute (ORS) Chapters 469.375, 469.525, 469.556, 469.559;
Oregon Administrative Rules (OAR) Chapter 345, Division 50, Section 006 through 130, Energy
Facility Siting Council, Radioactive Waste Materials. These rules govern disposal of radioactive
material in Oregon. They are applicable. The rules include a Pathway Exemption (OAR) Chapter
345, Division 50, Section 035, which exempts certain materials from the rules. The pathway
exemption applies to material which does not exceed 500 millirem/year (57 /irem/hour). This
standard for gamma radiation was evaluated during the remedial alternative analysis.
8.2 Remedial Action Alternatives
8.2.1 Alternative 1 - No Further Action
Estimated cost: $0
Time to implement: No time required to implement
The NCP requires that a "no action" alternative be evaluated as a potential remedial alternative for
each Superfund site. For this alternative, no further action would be taken at the TWCA Site beyond
those remedial measures which have already been implemented (see Section 3.4 of this ROD). The
TWCA property is zoned for industrial use, and no zoning changes are planned for the foreseeable
future. The no further action alternative would not comply with the remedial action objectives for the
Site, as concentrations of contaminants which are above acceptable risk levels would remain on Site.
8.2.2 Alternative 2 - Limited Excavation and Off-Site Disposal of Soil with Gamma Radiation
Levels Exceeding 57 /trem/hour Over Background; Radon Controlling Construction
Methods Required for Future Buildings; Control of Future She Use; 5 Year Reviews
Estimated Cost: $20,000 capital costs (no O&M costs are associated with this remedy)
Time to Implement: 1 year
Chemical and Radionuclide Contamination
No further cleanup action is required to address risks from ingestion of surface and subsurface
chemical and radionuclide contamination and subsurface gamma radiation exposure under current and-
projected Site uses. Zoning, building codes, deed notices and/or deed restrictions would be relied on
to ensure that Site land use (for both the Main Plant and the Soil Amendment Area) does not change
to residential. Should excavation occur as part of future development of the TWCA Main Plant or
the Soil Amendment Area, excavated, material from the Site must be properly handled, and
excavation and disposal of Site material must comply with Federal and State laws.
If future activities disturb the subsurface radionuclides or PCB contamination in the southern
Fabrication Area and/or the subsurface radionuclide contamination under the former V-2 Pond in the
Extraction Area, or if these or other locations are subsequently found to act as sources of
contamination to the groundwater, action could be required for these areas. Actions required for
groundwater sources are covered under the Record of Decision for Final Remedial Action of
Groundwater and Sediments Operable Unit, Teledyne Wah Chang Albany Superfund Site, June 10,
1994.
72
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Action will be required to address risks posed by surface gamma radiation and radon (see below).
Additional action may be required for radionuclides as part of plant closure requirements administered
by the Oregon Department of Health.
Gamma Radiation
Areas with surface gamma radiation greater than 57 prem/hour over background levels will be
excavated and disposed of off Site. If this material does not pass the Oregon pathway exemption,
disposal will be in a low level radioactive waste landfill.
Contamination resulting in gamma radiation exposure greater than 57 prem/hour (500 millirem/year)
above background may fail the Oregon pathway exemption (OAR, 345-50-35, see Section 11) and
could be regulated as radioactive in the state of Oregon (OAR, 345-50-006 to 130).
Radon
Institutional controls, zoning, building codes, deed restrictions, or deed notices requiring radon
control in future buildings would be implemented for the Soil Amendment Area, and Main Plant areas
where radon in future buildings could pose an unacceptable risk. The controls would require that 1)
future buildings be constructed using radon controlling construction methods; and 2) following
construction, the air would be periodically tested for radon. If radon concentration exceeded the EPA
target level in effect at the time testing is done, additional controls would be required to reduce radon
levels below the EPA target levels. Compliance with these restrictions would meet EPA's remedial
•objective of reducing radon exposure. The cost of complying with the construction requirements is not
included in the estimated cost. However, the additional building costs are estimated to be small.
Other remedies for radon control were not explored except where they were part of the alternatives
for control of gamma radiation.
5 Year Reviews
Because waste is left in place above levels allowing unrestricted use a five year review would be
conducted. The five year review would ensure that the remedy remains protective and that current
and expected Site use does not change, or trigger the initiation of potential future action if needed.
8.23 Alternative 3 - Limited Excavation and Off-Site Disposal of Soil with Gamma Radiation
Levels Exceeding 57 prem/hour Over Background; Radon Controlling Building Methods
Required for Future Buildings; Control of Future Site Use; 5 Year Reviews; Capping of
Areas Above Selected Gamma Radiation Action Levels
This Alternative includes all measures in Alternative 2, plus the additional actions described below.
Areas with gamma radiation above the proposed action levels are capped with an asphalt cap designed
to provide a shield from gamma radiation exposure.
Three action levels for cleanup were evaluated, 20 /trem/hour above background, 10 ^rem/hour above
background, and background. Areas with gamma radiation exceeding the action level, but below 57
prem/hour would be capped to bring gamma radiation levels to the selected action level. The
73
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rationale for evaluating the three levels was as follows:
1) Contamination resulting in gamma radiation exposure greater than 20 jirerri/hour above
background exceeds the cleanup level prescribed in the Health and Environmental Protection
Standards for Uranium and Thorium Mill Tailings (42 CFR 192). Parts of this regulation are
relevant and appropriate (see Section 8.1).
2) Cleanup of soil exceeding 10 prem/hour above background was evaluated to meet the
requirement in the Oregon Environmental Cleanup Rules (OAR 340-122-040) which requires
that cleanup meet the lowest feasible level if cleanup to background levels is not feasible; and
3) Cleanup to background was evaluated to meet the requirement in the Oregon
Environmental Cleanup Rules for cleanup to background levels if feasible.
Table 8-1 shows the risks after cleanup to the three action levels evaluated. The areas slated for
remediation are "hot spots" within larger.areas. It is appropriate to calculate risks over the larger Site
areas. Using this approach, there is no significant difference between remediation to 10 prem/hour or
20 prem/hour over background.
In addition to protection from gamma radiation exposure, capping on the Main Plant and the Soil
Amendment Area would provide some radon control provided that the cap remained intact during
future construction. Additional radon control would be provided through the building restrictions
described in Alternative 2.
a) Capping of Areas Exceeding Background plus 20 urem/hour
Estimated Cost: $100,000 capital cost
$33,000 operation and maintenance
(present worth for 30 years at 5% discount rate)
Time to Implement: 1 year
The affected area under Alternative 3a totals 8240 square feet and includes portions of the parking lot
outside of the boundary of the Extraction Area, the former sand unloading area in the Fabrication
Area, and Schmidt Lake in the Solids Area (see Figures 6-5a, b, and c).
b) Capping of Areas Exceeding Background plus 10 urem/hour
Estimated Cost: $740,000 capital cost
$74,000 operation and maintenance
(present worth for 30 years at 5% discount rate)
Time to Implement: 1 year
The affected area under Alternative 3b totals 108,275 square feet and includes areas in the parking lot
outside of the boundary of the Extraction Area, the former sand unloading area in the Fabrication .
Area, and Schmidt Lake in the Solids Area (see Figures 6-5a, b, and c).
Although a significantly greater area is capped under this action level, selection of 10 /xrem/hour
would not provide a significant reduction in the risk from exposure to gamma radiation, when
74
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Table 8-1
Residual Risk Following Remediation to Specified Action Level
TWCA
Subarea
OC-01
PL-01
PL-02
SL-02
SAA
Average Gamma Exposure Rate (prem/hour)
Before
Remediation
26.24
14.99
23.94
13.79
15.81
After Remediation to:
< 20.5b
/^em/hour
16.59
13.50
17.44
12.92
15.72
<30.5b
^em/hour
21.03
14.63
21.58
13.53
15.72
Incremental Excess Lifetime Cancer Risk a
Before
Remediation
2.4E-4
6.9E-5
2.1E-4
5.1E-5
9.1E-6
After Remediation to:
< 20.5b
/xrem/hour
9.4E-5
4.6E-5
1.1E-4
3.7E-5
8.9E-6
< 30. 5b
^rem/hour
1.6E-4
6.4E-5
1.7E-4
4.7E-5
8.9E-6
a. Risks for industrial scenario except for SAA which used a farm worker scenario
b. 20.5 /^em/hour = background plus 10 /^em/hour. 30.5 ^em/hour = background plus 20 /irem/hour.
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compared to the action level zf 20 /*reas/hour evaluated in Alternative 3a (see Table 8-1).
c) Capping of Areas Exceeding Background Average Gamma Radiation
Estimated Cost: $4,520,000 capital cost
$1,860,000 operation and maintenance
(present worth for 30 years at 5% discount rate)
Time to Implement: 2 years
The affected area under Alternative 3c totals 1,862,305 square feet. On the Main Plant, this
alternative addresses large areas in the parking lot outside of the boundary of the Extraction Area, the
former sand unloading area in the Fabrication Area, and Schmidt Lake in the Solids Area, and
includes the entire Soil Amendment Area (see Figures 6-Sa, b, and c, and Figure 6-6).
Following this action, there would not be any excess risk from exposure to gamma radiation in the
remediated areas.
8.2.4 Alternative 4 - Limited Excavation and Off-Site Disposal of Soil with Gamma Radiation
Levels Exceeding 57 prem/hour Over Background; Radon Controlling Building Methods
Required for Future Buildings; Control of Future Site Use; 5 Year Reviews, Additional
Excavation of Soil in Areas Above Selected Gamma Radiation Action Levels; Disposal of
Soil in an Off-Site Landfill
This Alternative includes the measures in Alternative 2 plus the additional actions described below.
This Alternative differs from Alternative 3 in that soil exceeding gamma radiation action levels is
excavated and disposed of hi an off-site landfill rather than capped (the remedy in Alternative 3). The
same three potential action levels for excavation were evaluated: 20 prem/hour above background, 10
prem/hour above background, and background.
Areas with gamma radiation exceeding the action level are excavated to bring gamma radiation levels
to the selected action level. Excavated material is then disposed of off Site in accordance with
applicable regulations. Cost estimates are based on a presumed one foot depth of excavation.
In addition to protection from gamma radiation exposure, excavation on the Main Plant and the Soil
Amendment Area would provide some radon control by removing the source of the radon (the radium
contaminated soil). Additional radon control would be provided through the building restrictions
described in Alternative 2.
a) Excavation of Areas Exceeding Background plus 20 urem/hour.
Estimated Cost: $110,000 capital costs (no O&M costs are associated with this remedy)
Time to Implement: 1 year
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The affected area under Alternative 3 a totals 8240 square feet and includes portions of the parking lot
outside of the boundary of the Extraction Area, the former sand unloading area in the Fabrication
Area, and Schmidt Lake in the Solids Area (see Figures 6-5a, b, and c).
b) Excavation of Areas Exceeding Background plus 10 urem/hour.
Estimated Cost: $920,000 capital costs (no O&M costs are associated with this remedy)
Time to implement: 1 year
The affected area under Alternative 3b totals 108,275 square feet and includes areas in the parking lot
outside of the boundary of the Extraction Area, the former sand unloading area in the Fabrication
Area, and Schmidt Lake in the Solids Area (see Figures 6-Sa, b, and c).
Although a significantly greater area is excavated under this action level, selection of 10 /trem/hour
would not provide a significant reduction in the risk from exposure to gamma radiation, when
compared to the action level of 20 prem/hour evaluated in Alternative 4a (see Table 8-1).
c) Excavation of Areas Exceeding Background
Estimated Cost: $14,720,000 capital costs (no O&M costs are associated with this remedy)
Time to Implement: 2 years
The affected area under Alternative 3c totals 1,862,305 square feet. On the Main Plant this
alternative addresses large areas of the parking lot outside of the boundary of the Extraction Area, the
former sand unloading area in the Fabrication Area, and Schmidt Lake in the Solids Area, and
includes the entire Soil Amendment Area (see Figures 6-Sa, b, and c, and Figure 6-6).
Following this action, mere would not be any excess risk from exposure to gamma radiation or radon
in future buildings constructed on the remediated areas.
Control of radon in areas not requiring excavation would be provided through the radon controlling
buildings restrictions described in Alternative 2. These areas had radium concentrations which
indicated that radon would be a health risk, but did not show elevated gamma radiation levels.
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9.0 COMPARATIVE ANALYSIS OF AI.ITERNATTVES
The NCP requires that each remedial alternative analyzed in detail in the Feasibility Study be
evaluated according to specific criteria. The purpose of this evaluation is to promote consistent
identification of the relative advantages and disadvantages of each alternative, thereby guiding
selection of remedies offering the most effective and efficient means of achieving Site cleanup goals.
There are nine criteria by which feasible remedial alternatives are evaluated. While all nine criteria
are important, they are weighed differently in the decision-making process depending on whether they
describe a required level of performance (threshold criteria), provide for consideration of technical
merits (primary balancing criteria), or involve the evaluation of non-EPA reviewers that may
influence an EPA decision (modifying criteria).
9.1 Threshold Criteria
The remedial alternatives were first evaluated by comparison with the threshold criteria: overall
protection of human health and the environment and compliance with Applicable or Relevant and
Appropriate Requirements (ARARs). The threshold criteria must be fully satisfied by candidate
alternatives before the alternatives can be given further consideration in remedy selection.
9.1.1 Overall Protection of Human Health and the Environment
This criterion determines whether an alternative eliminates, reduces, or controls threats to public
health and the environment through institutional controls, engineering controls, or treatment.
Alternative 1 does not protect human health and the environment. Alternative 2 is not protective for
exposure to gamma radiation, but is protective for risks from chemical and radon exposure.
Alternative 3a, b, and c, and 4a, b, and c are adequately protective of human health and the.
environment.
9.1.2 Compliance with Applicable or Relevant and Appropriate Requirements (ARARs)
This criterion evaluates whether the alternative meets State and Federal environmental laws,
regulations, and other requirements that pertain to the site or, if not, determines if a waiver is
justified. CERCLA requires that remedial actions satisfy all identified ARARs.
An "applicable" requirement directly and fully addresses the situation at the site. It would legally
apply to the response action if that action were undertaken independently from any CERCLA
authority. A "relevant and appropriate" requirement is one that is designed to apply to problems
which are sufficiently similar tb the problem being addressed at the site, that its use is well suited to
the particular site.
Alternatives 1 and 2 do not comply with all Federal and State ARARs; a waiver is not justified for
these alternatives. The remaining alternatives comply with Federal ARARs.
The Oregon Environmental Cleanup Rules (OAR 340-122-040) require cleanup to background levels,
or the lowest concentration level feasible. Permanent solutions are preferred over other remedies.
Alternative 3a, b, and c may not meet the Oregon Rule preference for permanent remedies, because
waste is capped and remains on the Site. Alternative 3a, 3b, and 3c, and 4a, and 4b, may meet the
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Oregon cleanup rale requirement for a cleanup action to meet the lowest feasible cleanup level (the
feasibility is based on analyzing the alternatives against each other). Only Alternative 4c meets the
requirement of the Oregon Rule for cleanup to background, but this alternative may not satisfy the
feasibility requirement of the rule.
9.2 Primary Balancing Criteria
For those alternatives satisfying the threshold criteria (Alternatives 3 and 4), five primary balancing
criteria are used to evaluate other aspects of the potential remedies. No single alternative will
necessarily receive the highest evaluation for every balancing criterion. The five primary balancing
criteria are: Long-term effectiveness and permanence; reduction of toxicity, mobility, or volume
through treatment; short-term effectiveness; implementability; and cost.
9.2.1 Long-Term Effectiveness and Permanence
This criterion evaluates the ability of a remedial alternative to maintain reliable protection of human
health and the environment over time, once cleanup goals have been achieved.
Alternatives 1 and 2 do not provide adequate long-term effectiveness for control of gamma radiation.
Alternative 2 does provide long term effectiveness for radon control through the required building
. controls. Alternatives 3a, b, and c provide protectiveness as long as the cap is maintained.
Alternatives 4a, b, and c do not require maintenance because waste is removed from the Site.
Alternative 4c is the only alternative which does not require future radon control.
9.2.2 Reduction of Toxicity, Mobility, or Volume Through Treatment
This criterion evaluates the anticipated performance of the various treatment technologies and
addresses the statutory preference for selecting remedial actions that employ treatment technologies
which permanently and significantly reduce toxicity, mobility, or volume of the hazardous substances.
This preference is satisfied when treatment is used to reduce the principal threats at a Site through
destruction of toxic contaminants, irreversible reductions in contaminant mobility, or reductions in the
total volume of contaminated media.
There is no treatment technology for gamma radiation or radon. None of the alternatives provide
treatment.
9.2.3 Short-Term Effectiveness
The short-term effectiveness criterion focuses on the period of time needed to achieve protection of
human health and the environment, and adverse impacts which may occur during remedial
construction and remedial action, until cleanup goals are achieved.
Alternative 1 has no implementation time, but does not provide protection. All the other alternatives
are adequate with respect to their short-term effectiveness. Alternatives 3c and 4c take the longest
time to achieve the desired action levels. The likelihood of an impact on public health during
implementation of any of the remedial alternatives is remote. Except for Alternative 1, worker
protection will be required during remedy implementation for all alternatives.
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9.2.4 Implementability
This evaluation addresses the technical and administrative feasibility of implementing the alternatives,
including the availability of materials and services required to construct the remedy.
Alternative 2 is the easiest alternative to implement. Alternatives 3a and b, and 4a and b are easily
implemented in a shon time frame. Alternative 3c will take longer to implement because of the large
area to be capped. Alternative 4c is the hardest to implement based on the amount of material that
requires excavation.
9.2.5 Projected Costs
Present worth costs are used to evaluate and compare the estimated monetary value of each remedial
• alternative. Present worth costs are determined by summing the estimated capital costs and estimates
of the discounted operation and maintenance (O&M) costs over the projected lifetime of the remedial
alternative. Estimated present worth costs are based on a 30-year life of the remedial alternative
using a discount rate of 5 percent.
The 30-year present worth cost for each alternative is identified in the Summary of Alternatives,
Section 8. The costs range from $0 for Alternative 1 (No Action) to $14,720,000 for Alternative 4c.
Alternatives 3a and 4a provide the most cost effective protection. Alternatives 3b and 4b do not
provide a significantly greater risk reduction, but their cost is almost 10 time greater. Alternatives 3c
and 4c provide the most risk reduction, but the cost of the incremental reduction in risk is not cost
effective.
Alternative 4c is the only alternative where additional radon control would not be required, but the
cost of the alternative is cost prohibitive when compared to the cost of using radon controlling
building methods.
9.3 Modifying Criteria
The modifying criteria are used in the final analysis of remedial alternatives and are generally
considered in altering an otherwise viable alternative rather than deciding between very different
alternatives. The two modifying criteria are state and community acceptance.
9.3.1 State Acceptance
The state of Oregon has analyzed the alternatives provided in the RI/FS. The State believes that the
excavation remedies meet the Oregon cleanup rule preference for permanent remedies more than the
capping remedies. The State accepts 20 prem/hour over background as the proposed cleanup standard
for gamma radiation. The State of Oregon considers alternative 4a to meet State ARARs.
9.3.2 Community Acceptance
EPA did not receive any comments during the public comment period.
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10.0 SELECTED REMEDY
Based on CERCLA, the NCP, the administrative record, the comparative analysis of alternatives, and
public comments, EPA has selected Alternative 4a. This remedial alternative includes the following:
Excavation of contaminated material exceeding the gamma radiation action level of 20
/irem/hour above background levels;
Transportation of the excavated material to an appropriate off-site facility for disposal;
For areas of the Site where modelling indicates that radon concentrations in future buildings
could exceed 4 pCi/liter, institutional controls requiring that future buildings be constructed
using radon resistant construction methods;
Requirement that information on areas of subsurface PCB and radionuclide contamination
which do not pose a risk if they are not disturbed, be incorporated into the TWCA facilities
maintenance plan, and be made available to future Site purchasers or regulatory agencies;
Because the determination that action is not required for certain areas of the Site is based on
scenarios which do not allow unrestricted use, should excavation occur as part of future
development of the TWCA Main Plant or the Soil Amendment Area, excavated material must
be properly handled and disposed of in accordance with Federal and State laws; and
Institutional controls requiring that land use remain consistent with current industrial zoning.
Except as expressly stated in CERCLA, in the NCP, or in this ROD, this ROD is not designed to
address TWCA's ongoing operations or to preclude the need for TWCA's ongoing operations to
comply with other environmental laws or regulations. Regulation of TWCA's ongoing operations is
covered under RCRA and under other State and Federal environmental laws. Except as otherwise
stated in this ROD, determinations in this ROD are intended to apply to Site geographic areas rather
than to ongoing plant operations.
The determinations made hi this ROD regarding contamination of surface and subsurface soils apply
to areas of the Site investigated during the RI/FS, and are based on information from the RI/FS. As -
TWCA is an active operating facility, some on-site conditions may have changed since the RI/FS.
Material placed in CERCLA investigated areas subsequent to the RI/FS sampling may not necessarily
be addressed by this ROD, but may be investigated and addressed under. RCRA. Similarly, not all
excavations on the Site are covered by this ROD.
Areas of surface and subsurface soil contamination not addressed during the RI/FS and therefore not
addressed in this ROD, but which are later found to be sources or potential sources of groundwater
contamination are addressed in the Record of Decision for Final Remedial Action of Groundwater and
Sediments Operable Unit, Teledyne Wan Chang Albany Superfund Site, June 10, 1994. Areas of the
Site or contamination at the Site, not addressed by either the groundwater ROD or this ROD, are
subject to investigation and corrective action under RCRA. For conditions or contamination at the
Site previously unknown that are later discovered, such conditions or contamination may be addressed
under either RCRA or CERCLA. In addition, under the NORM license administered by the.Oregon
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Department of Health, TWCA will be required to remediate remaining radioactive material when the
plant closes.
The following section provides an additional description of the selected remedy.
10.1 Remedial Action for Gamma Radiation
Areas with surface gamma radiation levels exceeding 20 jtrem/hour over background levels (equal to
30.5 /xrem/hour) averaged over 100 square meters will be excavated, and the soil disposed of off Site.
These areas are located on the Main Plant and include areas in the parking lot outside of the
boundaries of the Extraction Area, the former sand unloading area in the Fabrication Area, and
Schmidt Lake. The approximate areas to be excavated are shown in Figures 10-la, b, and c.
Material which does not pass the Oregon Pathway Exemption (OAR 345-50-035), most likely material
from the former sand unloading area, will be disposed of in a low level radioactive disposal facility,
which meets the requirements of the Offsite Rule (40 C.F.R. §300.440). Material which meets the
Oregon Pathway Exemption must be disposed of in a facility meeting the requirements of the Offsite
Rule.
The cost estimates and feasibility analyses used in the selection of this remedy were based on an
assumed excavation depth of one foot. This remedy may be reconsidered if it is determined that a
significantly greater amount of material requires excavation. Two potential methodologies are offered
here to further quantify the amount of material to be excavated. Other methodologies may also be
appropriate:
1) During remedial design, the depth of gamma emitting material can be evaluated to determine
volumes and the nature of the material;
2) During remedial action, after one foot of excavation, areas are resurveyed, and if gamma survey
readings exceed 20 /*R/hour over background, additional samples may be taken, and other options
may be evaluated before proceeding.
Among the factors which may be considered by EPA in determining the additional
amount of material to excavate will be, satisfying surface exposure requirements, the type of material
which is found and whether the material in question is teachable (or has leached) posing a potential
groundwater source, whether the surface readings result in finding buried radioactive material, and
State acceptance.
10.2 Remedial Action for Radon
Action for radon is required for the entire Soil Amendment Area, and for areas on the Main Plant
plan where surface and subsurface soil radium-226 concentrations exceed 3 pCi/gram. These areas
could exceed the action level for radon of 4 pCi/liter if buildings are constructed in the future.
On the Main Plant, the soil radium standard applies to both areas where surface soil exceeds 3
pCi/gram (shown in Table 6-7) and areas where subsurface soil radium-226 concentrations exceed
this standard (samples from borings B-l, B-2, B 91-6, PW-03A, and the V-2 Pond exceed this
standard). The locations are shown on Figures 10-2a, b, and c.
The selected remedy requires that future buildings be constructed using radon controlling construction
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LE08O-
STREAM SOUNDART
. - TOPOGRAPHICAL LINE
DIRT ROAO
— • EXISTING FENCE
EXTRACTION
AREA /
BOUNDARY
[PL-Oil CAUUA EXPOSURE
\ \ PARKING LO
\ \ SUBARCA —
Areas Exceeding Action Level
For Gamma Radiation
Figure 10-la
Areas Exceeding Action Level
For Gamma Radiation
Parking Lot Area
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CXR1 ROAD
EXISTING r
foc-oTl CAMWA rxPQSuRf
Lr^. °H SURVEY SU5A9CA
tt—C.':...
Areas' Exceeding Action Level
For Gamma Radiation
\
\-\\\\ \\
Figure 10-lb
Areas Exceeding Action Level
For Gamma Radiation
Former Sand Unloading Area
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LECBO
SIRCAM BOUNDARY
_^.»l»--^ TOPOGRAPHICAL UNt
-^_- DIRTDOAO
CXISTINQ rtNce
Areas Exceeding Action Level
For Gamma Radiation
Figure 10- Ic
Areas Exceeding Action Level
For Gamma Radiation
Schmidt Lake
v C -•••-*
-------
J ; /I/
10-2a
Areas Exceeding Radon Action Level
Extraction Area
•«»
-------
COOUNG WX
PONO AREA Cw „.
Areas Exceeding Radon Action Levd
STRDUI 8P3UNOAAY
TOPOOttPHKM. UNE
->_» O1RTROAO
Figure 10-2b
Ar>eas Ezcpeeding Radon Action Levd
Fabrication Area
rr-
-------
Areas Exceeding Radon Action Level
STREAM BOUNDARY
.__. OIRTBOAO
. . . . SURTACC SOD. SAMPUNC 1RANSECT
??\ BAtXOtOUNO SURFACE SOU.
<<^9 SAMPLE AR£A (APPROX LOCATION.
AREA «Ot TO SCALE)
FP-«7«S CRAB SAMPLE LOCATIONS
Figure 10-2c
Areas Exceeding Radon Action Level
Soil Amendment Area
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metl.ods. Following construction, the air shall be periodically tested for radon. If radcn
concentration exceeded the EPA target level or promulgated standard in effect at the time of these
future sampling events, additional controls will be required to reduce radon levels below the EPA
target level or promulgated standard. Because the action level of 4 pCi/liter is a technology based
standard, rather than a risk based level, this ROD does not "freeze" the required level.
The requirements would be embodied in zoning, institutional controls, building codes, deed
restrictions, or deed notices placed on the entire Soil Amendment Area, and the Main Plant areas
exceeding the radium standard. For the Soil Amendment Area, it is expected that the City of
Millersburg, the current owner of the property, will institute a zoning requirement.
Current technology for construction of radon resistant buildings is described in the document Radon
Prevention in the Design and Construction of Schools and Other Large Buildings (EPA/626/R-92/016.
1994) Compliance with these restrictions would meet EPA's remedial objective of reducing radon
exposure.
The only other effective remedial alternative for mitigation of radon in the Soil Amendment Area was
excavation of soil to background levels. This option was eliminated as being prohibitively expensive.
Current plans for the Soil Amendment Area are for use as an industrial park. During a meeting with
the city of Millersburg, it was suggested that the contaminated material in the Soil Amendment Area
might be excavated and used to construct landscaping and berms. The efficacy of this potential option
has not been considered. However, if it is later offered as a potential option by
the City, proves viable, and meets the remedy selection criteria, EPA may reconsider this portion of
the selected remedy.
103 'Chemical and Radionuclide Contamination
No further cleanup action is required to address risks from ingestion of surface and subsurface
chemical and radionuclide contamination and subsurface gamma radiation exposure under current and
projected Site uses. Zoning, building codes, deed notices and/or deed restrictions would be relied on
to ensure that Site land use (for both the Main Plant and the Soil Amendment Area) does not change
to residential. The current zoning for the Main Plant and the Soil Amendment Area is industrial.
Industrial zoning in the Soil Amendment Area allows for agricultural use. As shown in the risk
assessment, this use is acceptable. The five year review would be required to ensure that the remedy-
remains protective and that current and expected Site use does not change.
Three sample locations had high concentrations of subsurface radium-226. These were B-2, and B-
91-6 in the south end of the Fabrication Area, and the former V-2 Pond in the Extraction Area. For
this subsurface radionuclide contamination, restrictions for radon control will be required (discussed
below). Action may be required for this material as part of plant closure requirements administered
by the Oregon Department of Health. There were also high subsurface levels of PCBs in the southern
Fabrication Area in the vicinity of boring B-2. Should excavation occur in the areas with subsurface
radionuclides or PCBs, the excavated material will require proper handling and disposal. Information.
on the subsurface areas of contamination shall be made available to future TWCA workers as pan of
the TWCA Facilities Excavation Plan, and to potential Site purchasers, and regulatory agencies. In
addition, if these locations or other currently unknown areas are subsequently found to act as sources
of contamination to the groundwater, action could be required for these areas. Actions required for
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groundwaier sources s-e covered under the Record of Decision for Final Remedial Action of
Groundwater and Sediments Operable Unit, Teledyne Wah Chang Albany Superfund Site, June 10,
1994.
•
For radionuclide contamination, action will be required to address risks posed by surface gamma
radiation and radon (see above). Additional action may be required for radionuclides as part of plant
closure requirements administered by the Oregon Department of Health. .
As stated above, concentrations of chemical and radionuclide contamination in the surface and
subsurface soils of the Main Plant and Soil Amendment Area are within acceptable risk levels (except
as discussed for remediation of gamma radiation and radon). However, this determination only
applies to certain risk scenarios, and assumes the material stays where it is currently located. The
soils may be above standards that allow its unrestricted use or disposal (i.e., excavated material from
the TWCA Main Plant or the Soil Amendment Area cannot be used as fill material in residential
areas, and must be disposed of in accordance with the Offsite Rule). Should excavation occur during
future development of the TWCA Main Plant or the Soil Amendment Area, excavated material must
be properly handled, and excavation and disposal of Site material must comply with Federal and State
laws.
10.4 CERCLA FwsYear Review
Section 121(c) of CERCLA and Section 300.430(f)(4)(ii) of the NCP require a review of the remedial
action no less often than once every five years if the selected remedy "results in hazardous
substances, pollutants, or contaminants remaining on the Site above levels that allow for unlimited use
and unrestricted exposure". Statutory reviews must continue at least every five years until
contaminant levels allow for unlimited use and unrestricted exposure.
The selected remedy relies on an industrial scenario, and therefore does not allow unlimited and
unrestricted use. As contaminants will remain on Site that are above risk-based levels, the selected
remedy requires that statutory reviews be conducted at least every five years. This element of the
selected remedy also recognizes that TWCA is an active facility with ongoing operations which have
impacted and limited the scope of the RI/FS, and which may continue to influence the effectiveness of
remedial actions.
10.5 Costs • . . -
The selected remedy is expected to cost $110,000 for capital costs. There are no operation and
maintenance costs associated with the remedy. The cost consists of $20,000 for removal and disposal
of material with gamma radiation levels greater than 57 prem/hour, and $90,000 for removal of the
remaining material above 20 /irem/hour over background. The costs for construction of buildings
using radon resistant technology is not included. A cost breakdown is shown in Table 10-1.
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Table 10-1
Cost Breakdown for the Selected Remedy (
Remedy Component
Quantity
Unit Price
Component Cost
Excavation of Material over 57/^Rein/hour
6' tons
$59
$354
Disposal
95 Cubic
Feet
$70.37
6685
Excavation/Disposal of Material over 20 ^Rem/hour
500 tons
$59
$29,500
Backfilling
506 tons
$18
$9108
Oversight
$3000
Field Management
$4800
Capital Cost Subtotal
$53,000
Mobilization and Genera! Requirements @ 15%
$8000
Construction Cost Subtotal
$61,000
Bid and Scope Contingencies 20%
$12,100
Subtotal
$73,100
Administrative and other Costs 20%
$14,600
Total Implementation Costs
$87,700
Engineering Design @20%
$22,000
Total Capital Costs
$110,000
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11.0 STATUTORY DETERMINATIONS
Under CERCLA, EPA's primary responsibility is to ensure remedial actions are undertaken which
protect human health, welfare, and the environment. In addition, Section 121 of CERCLA, 42
U.S.C. §9621, establishes cleanup standards which require that the selected remedial action complies
with all ARARs established under Federal and State environmental law, unless such requirements are
waived by EPA in accordance with established criteria. The selected remedy must also be cost-
effective and must utilize permanent solutions, alternative treatment technologies, or resource
recovery technologies to the maximum extent practicable. Finally, CERCLA regulations include a
preference for remedies that employ treatment that permanently and significantly reduces the volume,
toxicity, or mobility of hazardous waste. The following sections discuss how the selected remedy for
the TWCA Site meets these CERCLA requirements.
11.1 Protection of Human Health and the Environment
The selected remedy combines institutional controls, excavation and off-site disposal, and mitigation
measures which are designed to be protective of human health and the environment. The selected
remedy takes into account the fact that TWCA is an active facility and that it may not be possible to
completely eliminate or reduce all potential sources of contamination without substantially interfering
with TWCA's ongoing processes. The goal of the selected remedy is to achieve protection of human
health and the environment while giving reasonable consideration to those factors.
The selected remedy uses institutional controls to ensure that Site use remains consistent with current
usage. Under the current usage, risks associated with exposure to chemicals and radionuclides (with
the exceptions of radon and surface gamma radiation exposure) are within acceptable levels.
Excavation of surface soil resulting in gamma radiation greater than 20 /trem/hour over background
reduces the health risk posed by exposure to gamma radiation to within acceptable levels. The
requirement that future buildings be constructed using radon resistant technology will reduce the risk
from exposure to radon.
Implementation of the remedy will not pose unacceptable short term risks.
11.2 Compliance with Applicable or Relevant and Appropriate Requirements (ARARs)
The selected remedy will comply with all chemical-specific, action-specific, and location-specific
ARARs that have been identified. In addition, other regulations and guidance were considered in the
selection of the remedy. No waiver of any ARAR is being sought or invoked for any component of
the selected remedy.
The ARARs identified for the TWCA Site include the following:
1. Health and Environmental Protection Standards for Uranium and Thorium Mill
Tailings, 40 C.F.R. §192, Authority: Sec. 275 of the Atomic Energy Act of 1954, 42
U.S.C. §2022, as added by the Uranium Mill Tailings Radiation Control Act of 1978,
Pub. L. 95-604, as amended. Portions of these standards are relevant and appropriate.
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2. Solid Waste Disposal Act, also known as the Resource Conservation ind Recovery Act
(RCRA), Subchapter HI, (42 U.S.C §§6921-6939) RCRA Land Disposal Treatment
Standards, 40 C.F.R. Part 268, Subpart D; RCRA Transportation regulations, 40
C.F.R. Part 263. Excavated soil will be analyzed to determine whether or not it exhibits
RCRA hazardous waste characteristics. If the soil is a RCRA hazardous waste, or must be
managed as RCRA hazardous waste, then the above ARARs are applicable.
3. Toxic Substances Control Act (TSCA 15 U.S.C. §§2601-2671) PCB Disposal regulations
at 40 C.F.R. §761.60; Oregon Hazardous Waste Management Rules for PCBs, OAR 340-
110. These regulations may be applicable for PCB-contaminated materials that are disposed
off Site.
4. Clean Air Act, 42 U.S.C. §§7401 et seq.. (CAA), National Primary and Secondary
Ambient Air Quality Standards, 40 C.F.R. Part 50; CAA National Emissions Standards
for Hazardous Air Pollutants, 40 C.F.R. Part 60; CAA New Source Performance
Standards, 40 C.F.R. Part 61. The CAA regulations are applicable for control of dust
particles emitted into die air during remediation construction activities.
5. Amendment to NCP, Procedures for Planning and Implementing Off-Site Response
Actions, 40 C.F.R. §300.440. These rules and requirements are applicable to off-site
management of CERCLA hazardous substances, pollutants or contaminants resulting from this
ROD.
6. Oregon Environmental Cleanup Law, Oregon Revised Statute (ORS) Chapter 465;
Oregon Environmental Cleanup Rules, Oregon Administrative Rule (OAR) Chapter 340,
Division 122, Sections 10 through 110. These regulations are applicable for Site soils.
These rules require cleanup to background or the lowest feasible level.
7. Energy Conservation, Oregon Revised Statute (ORS) Chapters 469.375, 469.525,
469.556, 469.559; Oregon Administrative Rules (OAR) Chapter 345, Division 50, Section
006 through 130, Energy Facility Siting Council, Radioactive Waste Materials. These
rules govern disposal of radioactive material in Oregon. They are applicable. The rules
include a Pathway Exemption, (OAR) Chapter 345, Division SO, Section 035, which exempts
certain materials from the rules.
8. Oregon Hazardous Waste Managomont Rules, OAR 340-100; Oregon Standards
Applicable to Generators of Hazardous Waste, OAR 340-102; Identification and Listing
of Hazardous Wastes, OAR 340-101. These regulations may be applicable for the off-site
disposal and on-site management of hazardous wastes.
9. Administrative Rules for Waste Management, Oregon Revised Statue (ORS) Chapter
459, Oregon Administrative Rules (OAR) Chapter 340 Division 93 through 97. These
rules cover the disposal of solid waste (material that is not hazardous waste). They are
applicable to the disposal of site soils.
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1C. Executive Order 11988, Floodplain Management, and Executive Order 11990, Protection
of Wetlands, May 24, 1977, incorporated in Appendix A to 40 C.F.R. Part 6. These
orders are applicable if wetlands are impacted. The. selected remedy is not expected to have
an impact on wetlands at the Site.
11. Oregon's statewide planning goals, Goal 5 (Open Spaces, Scenic and Historic Areas, and
Natural Resources), Goal 6 (Air, Water and Land Resources Quality), Goal 7 (Areas
Subject to Natural Disaster and Hazards) and Goal 15 (Willamette River Greenway).
These regulations are applicable for those portions of the TWCA Site that lie within the
Willamette River floodplain. The City of Millersburg is the local jurisdiction responsible for
ensuring the objectives of these goals are satisfied. Remedial actions planned for these areas
will need to be cleared through the City of Millersburg under its floodplain ordinance.
The policy, guidance, and regulations considered in the selection of the remedy,or which impact the
remedy include the following:
1. Occupational Safety and Health Act (OSHA), 29 U.S.C. 651; the implementing
regulations under OSHA, 20 C.F.R. Parts 1910 and 1926. These regulations must be
complied with.
2. Oregon Administrative Rules, OAR 333 Division 120 Sections 020, and 180, Oregon Rules
for the Control of Radiation. The OAR, Chapter 333, Division 120 - Health Division,
General Provisions states each licensee or registrant shall conduct operations so that the total
effective dose equivalent to individual members of the public from the licensed or registered
operation does not exceed 0.1 rem (100 mrem) in a year. Also, the provision states that the
dose in any unrestricted area from external sources shall not exceed 0.002 rem (2000 /trem)
in any one hour. Application can be made for authorization to operate up to an annual dose
limit for an individual member of the public of 0.5 rem (500 mrem). These regulations may
be applied by the Oregon Health Department upon plant closure.
3. The EPA action level of 4.0 pCi/1 of indoor radon is commonly recognized by Federal (and
ODEQ) agencies as an upper limit on radon exposure in the home. This is equivalent to*
0.02 WL (Lung Cancer Risk from Indoor Exposures to Radon Daughters, Internal
Commission on Radiological Protection (ICRP) Publication SO, 1987, Pergamon Press,
Oxford).
4. Radon Prevention in the Design and Construction of Schools and Other Large Buildings.
Third Printing with Addendum. 1994. (EPA/62S/R-92/016). This guidance describes
construction methods for radon resistant buildings.
11.3 Cost Effectiveness
EPA has determined that the combination of remedial actions identified as the selected remedy will
reduce or eliminate the risks to human health in a cost-effective manner. The costs associated with
the selected action level is almost an order of magnitude less than the cost of remediation to the next
lowest action level (which did not provide significantly greater protection). The use of radon resistant
construction for radon remediation is the only cost effective alternative.
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Ii.4 Utilization of Permanent Solutions and Resource Recovery Technologies to the
Maximum Extent Practicable
The selected remedy does not employ treatment technologies or resource recovery technologies. No
such technology is available for the principle threats posed by the Site,'risks from exposure to gamma
radiation and radon. Removal provides a permanent solution because waste is removed from the Site.
11.5 Preference for Treatment as a Principal Element
The selected remedy does not contain treatment as a principal element. There is no treatment
technology for the principal threats posed by the Site, risks from gamma radiation and radon.
11.6 Community Acceptance
There were no public comments received during the public comment period held from August 1 to
August 30, 1995.
11.7 Conclusions
The selected remedy achieves the best balance among the nine evaluation criteria. The selected
remedy achieves the best balance of tradeoffs with respect to the primary balancing criteria of long-
term effectiveness and permanence; reduction in toxicity, mobility, and volume through treatment;
short term effectiveness; implementability; and cost.
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12.0 DOCUMENTATION OF SIGNIFICANT DIFFERENCES
The selected remedy does not differ from the preferred alternative in the Proposed Plan.
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APPENDIX A
Responsiveness Summary
The purpose of this responsiveness summary is to summarize and respond to public comments
submitted regarding the Proposed Plan for the cleanup of the Teledyne Wah Chang Albany (TWCA)
Superfund Site. The public comment period for the Proposed Plan was held from August 1 to August
30, 1995
This responsiveness summary meets the requirements of Section 117 of the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) as amended by the
Superfund Amendments and Reauthorization Act of 1986 (SARA).
In the Proposed Plan, issued July 21, 1995, the U.S: Environmental Protection Agency (EPA)
described alternatives considered for the cleanup of surface and subsurface soils at the TWCA Site.
These cleanup alternatives were based on information collected during a Remedial Investigation and
Feasibility Study (RI/FS) conducted on the Site. The purpose of an RI/FS was to conduct a study of
the Site and to assess possible plans to clean up the Site. The RI/FS and Proposed Plan were
available at the Albany Public Library. Copies of the Proposed Plan and/or a- fact sheet describing
the Proposed Plan were mailed to the citizens whose names were on a list developed as part of the.
Community Relations Plan.
EPA offered the public the opportunity to have a public meeting. Only one person called to express
interest. EPA responded by sending the caller a copy of the proposed plan.. Later attempts to contact
the caller by phone to determine whether there were any additional concerns were unsuccessful.
Because only one request for a meeting was received, EPA did not hold a public meeting. No
comments were received during the public comment period.
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Teledyne Wah Chang
Surface and Subsurface Soil Operable Unit
Administrative Record
Table of Contents and Index
DUE TO ITS LARGE SIZE,
THE ADMINISTRATIVE RECORD
HAS BEEN OMITTED
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