Environmental Protection
Agency
Radiation
Office of
Radiation Programs
Washington DC 20460
EPA 520/4-80-011
December 1980
Draft
Environmental
Impact Statement
for Remedial Action
Standards for Inactive
Uranium Processing Sites
(40 CFR 192)
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EPA 520/4-80-011
Draft
Environmental Impact Statement
for
Remedial Action Standards
for
Inactive Uranium Processing Sites
(40 CFR 192)
December 1980
Office of Radiation Programs
Environmental Protection Agency
Washington, D.C. 20460
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FOREWORD
(X) Draft Environmental Statement
( ) Final Environmental Statement
Environmental Protection Agency
Office of Radiation Programs
1. This Environmental Impact Statement was prepared by the Criteria and
Standards Division (CSD), Office of Radiation Programs (ORP), U.S.
Environmental Protection Agency (EPA).
Questions regarding this statement should be directed to Stanley
Lichtman, Project Leader, in care of the Director, Criteria & Standards
Division, or at (703) 557-8927.
2. EPA is proposing standards for the disposal of uranium mill tailings
from inactive processing sites, and for cleanup of land and buildings
contaminated by tailings. EPA developed these standards pursuant to the
Uranium Mill Tailings Radiation Control Act of 1978 (PL 95-604). The Act
requires EPA to set generally applicable standards to protect the public
health, safety, and the environment from hazards posed by uranium mill
tailings at specific inactive processing sites. The 25 sites initially
designated are in Arizona, Colorado, Idaho, New Mexico, North Dakota,
Oregon, Pennsylvania, Texas, Utah, and Wyoming.
3. In developing a standard, EPA staff members meet with individuals and
organizations to seek both information and a thorough understanding of the
issues. The staff then independently assesses the considerations specified
in EPA's Regulation EIS Procedures (39 F.R. 37419, October 21, 1974).
4. This evaluation leads to the publication of a Draft Environmental
Impact Statement (DEIS), which is circulated to appropriate governmental
agencies for comment. For this DEIS, EPA gained considerable information
from the Draft Generic Environmental Impact Statement on Uranium Milling
(NUREG-0511) prepared by the U.S. Nuclear Regulatory Commission (NRC).
EPA has notified the public through the Federal Register that the DEIS is
available, and has invited interested persons to comment on the draft
statement and the proposed standards.
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Single copies of this statement may be obtained from:
Director, Criteria and Standards Division
Office of Radiation Programs (ANR-460)
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
5. After considering comments on the Draft EIS, EPA will prepare a Final
EIS (FEIS) which will include a discussion of the concerns raised and the
conclusions EPA reached. EPA then will release the Final Environmental
Impact Statement.
6. EPA has asked the following Federal agencies to comment on this
statement:
Advisory Council on Historic Preservation
Department of Agriculture
Department of the Army, Corp of Engineers
Department of Commerce
Department of Energy
Department of Health, Education & Welfare
Department of Housing and'Urban Development
Department of the Interior
Department of Justice
Department of Transportation
Federal Energy Regulatory Commission
Nuclear Regulatory Commission
EPA also has sent copies to all State Clearinghouses, to the American
Mining Congress and to other individuals and organizations who have
notified EPA of their interest.
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CONTENTS
~?aee
Foreword • i
Contents iii
Tables vi
Figures viii
Summary . . S-l
1: Introduction 1-1
2: Uranium Milling Operations 2-1
. 2.1 History of Uranium Milling Operations 2-1
2.2 Status of Milling Sites 2-4
2.3 The Inactive Sites 2-6
2.3.1 The Phase I Studies 2-6
2.3.2 The Phase II Studies 2-18
References for Chapter 2 2-19
3: Source Terms 3-1
3.1 Introduction 3-1
3.2 Radioactivity Source Terms 3-1
3.3 Nonradioactive Contaminants .......... 3-6
3.4 Off-Site Contamination 3-9
References for Chapter 3 3-17
4: Health Effects 4-1
4.1 Introduction 4-1
4.2 Radon and Its Immediate Decay Products .......... 4-4
4.3 Estimates of the Lung Cancer Risks from Inhaling Radon
Decay Products 4-6
4.4 Impact on Local and Regional Population from Radon
Decay Products 4-11
4.5 Risks to the Continental U.S. Population from Radon
Emitted from Inactive Piles 4-20
4.6 Regional and National Effect from Long Half-Life
Radioactive Materials 4-23
4.7 Impact from Gamma-Ray Exposure 4-26
4.8 Hazard from Water Contamination . . ./ 4-30
4.8.1 Introduction *-30
4.8.2 Movement of Toxic Chemicals from Tailings 4-33
4.8.3 Toxicity of Major Toxic Substances
Found in Tailings 4-36
4.9 Conclusions ^-37
References for Chapter 4 4-40
111
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5: Alternative Tailings Disposal Control Levels .......... 5-1
5.1 Introduction ....................... 5_1
5.2 Control of Radon-222 Releases ......... '.*.'.'.*. 5-2
5.2.1 Radon Control ................... 5_3
5.2.2 Effects of Radon Control on Release of
Airborne Particulates .............. 5-6
5.2.3 Effects of Radon Control on Direct
Gamma Radiation ................. 5_y
5.2.4 Effects of Radon Control on Potential
Water Contamination ............... 5_7
5.3 Control of Surface and Ground Water Contamination .... 5-9
5.4 Longevity of Control ................... 5-,12
5.4.1 Effects of Natural Forces .......... ... 5-12
5.4.1.1 Earthquakes ................. 5-13
5.4.1.2 Floods ................... 5-14
5.4.1.3 Windstorms and Tornadoes .......... 5-14
5.4.1.4 Glaciation ................. 5-14
5.4.2 Effects of Human Activity ............. 5-15
References for Chapter 5 ................... 5_17
6: Monetary Costs and the Effects of Tailings Disposal ...... 6-1
6.1 Estimated Costs ....... .............. 6-1
6.2 Estimated Health Benefits ........ . ....... g_4
6.3 Longevity of Controls ........... . ...... g_g
6.4 Environmental Impacts of Control Actions ......... 6-9
6.5 Occupational Hazards ................. t 6-10
6.6 Local Economic Considerations at the Local Level ..... 6-10
References for Chapter 6 ................... 6-11
7: Considerations for Cleanup of Contaminated
Land and Buildings _1
7.1 Introduction ................ t> 71
7.2 Off-Site Contamination ............ ' * " ' y_i
7.3 Potential Hazards of Off-Site Contamination ..'!.'.'! .' 7-2
7.4 Remedial Actions and Costs ........... * \ \ \ 7.5
7.5 Previous Standards for Indoor Radon
Decay Product Concentration .............. 7_7
7.6 Normal Indoor Radon Decay Product Concentrations ..... 7-8
7.7 Practicality of Alternative Remedial
Action Standards for Buildings ............. 7-11
References for Chapter 7 ............ 1111111 7-14
8: Selecting the Proposed Standards ....... . ........ g_l
8.1 Disposal Standards ........ ...... .1111! 8-1
8.1.1 Radon Standard .............. !!!!." 8-2
8.1.2 Ground Water Standard ........ .111111 8-8
8.1.3 Surface Water Protection ........ .'.".'.*.".* 8-16
8.1.4 Remedial Action for Existing Ground
Water Contamination ............... g_13
8.1.5 Period of Application of Disposal Standards 1 1 1 1 8-20
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8.2 Cleanup Standards 8-22
8.2.1 Open Lands 8-22
8.2.2 Buildings 8-25
8.2.2.1 Indoor Radon Decay Product
Concentration Standards 8-25
8.2.2.1 Standards for Indoor Gamma Radiation .... 8-28
8.2.2.3 Radiation Hazards not Associated
with Radium-226 8-29
References for Chapter 8 8-31
9: Implementation 9-1
9.1 Administrative Process 9-1
9.1.1 Disposal Standards 9-1
9.1.2 Cleanup Standards 9-2
9.1.2.1 Purpose of Cleanup Standards 9-2
9.2 Exceptions 9-3
9.3 Effects of Implementing the Standards • • 9-6
9.3.1 Health 9-6
9.3.2 Environmental 9-7
9.3.3 Economic 9-7
9.4 The Proposed Standards 9-9
References for Chapter 9 9-10
Appendix A - Comments and Responses to Comments (Reserved) A-l
Appendix B - Development of Cost Estimates B-l
Appendix C - Toxicologies of Toxic Substances in Tailings C-l
Appendix D - The Proposed Standards D-l
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TABLES
Page
2-1 Number of Active and Inactive Uranium Mill Sites 2-5
2-2 Inactive Mill Sites 2-7,8
2-3 Summary of Conditions Noted at Time of Phase I
Site Visits . 2-11,12
2-4 Summary of Phase I Findings and Principal Action
to be Studied in Phase II 2-16,17
3-1 Radioactivity in Inactive Uranium Mill Tailings
Piles 3-2,3
3-2 Elements and Compounds Measured in an Inactive
Tailings Pile 3-7
3-3 Additional Elements and Compounds Found in
Uranium Mill Tailings 3-8
3-4 Elements/Compounds Reported in Elevated Concentrations
in Ground Water in the Vicinity of Tailings Piles 3-10
3-5 Gamma Radiation Anomalies and Causes 3-12,13,14
3-6 Contaminated Areas Around Inactive Uranium Mill
Tailings Piles 3-15,16
4-1 Estimated Effect on Local and .Regional Populations
from Exposure to Radon Decay Products from
Tailings Piles 4-14,15,16
4-2 Individual Risk from Lifetime Exposure to Radon
Decay Products from Tailings Piles 4-18
4-3 Estimated Risk to Nearest Residents from Inhaling
Radon Decay Products from Tailings Piles 4-19
4-4 Risk from Background Radon in Residential Structures .... 4-21
4-5 Approximate Contribution of Tailing Piles at
Inactive Sites to the National Health Risk from
Radon Decay Products 4-24
-6 Summary Table — Tailings Piles at Inactive Sites;
Estimated National Risk of Fatal Lung Cancer from
Radon Emissions ».... 4-25
VI
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4-7 Regional Impact from Uranium Mill Tailings . . 4-27
4-8 Increased Gamma Ray Dose Rates from Tailings
Piles at Inactive Sites 4-29
4-9 Estimated Lifetime Risk of Fatal Cancer from Total
Body Gamma-ray Exposure at 100 mR/yr 4-31
4-10 Estimated Risk of Serious Genetic Abnormalities ........ 4-32
4-11 Summary — Risks from Radon Emitted from Tailings Piles
at Inactive Sites 4-39
5-1 Nominal Half-Value-Layers of Typical Natural Materials
for Reducing Radon Releases 5-4
6-1 Ranges of Estimated Costs by Disposal Option and
Radon Control Level 6-3
6-2 General Post-Disposal Benefits of Disposal Options ...... 6-7
7-1 Average Annual Radon Decay Product Concentrations in
Normal Buildings ..... 7-10
7-2 Experience with Grand Junction Remedial Action Program .... 7-12
VII
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FIGURES
Page
4-1 Uranium-238 Decay Series ........ 4-2
4-2 Lung Cancers as a Function of Cumulative WL Months 4-7
5-1 Percentage of Radon Penetrating a Cover 5-5
5-2 Percentage of Gamma Radiation Penetrating a
Cover 5-8
viii
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SUMMARY
The Environmental Protection Agency (EPA) is proposing standards for
disposing of uranium mill tailings from inactive processing sites and for
cleaning up contaminated open land and buildings. These standards were
developed pursuant to the Uranium Mill Tailings Radiation Control Act of
1978 (Public Law 95-604). This Act requires EPA to promulgate standards
that can be generally applied to protect the environment and the public
health and safety from radioactive and nonradioactive hazards posed by
uranium mill tailings at designated inactive processing sites. The 25
presently designated sites are inactive uranium mill tailings piles in the
States of Arizona, Colorado, Idaho, New Mexico, North Dakota, Oregon,
Texas, Utah, and Wyoming and at the location of a former rare-metals plant
in Pennsylvania.
1. The Proposed Standards Cover Two Situations
a. Disposal of Tailings:
The standards limit release of radon gas to the air from disposed
tailings to 2 picocuries per square meter per second (pCi/m2-sec), about
twice the average of normal soils. When the radon from a cover of normal
soil is added to that allowed from tailings, the resulting release will
still be within a normal range of variation. The standards restrict con-
tamination of drinkable ground water to preserve its potability. Lower
quality but potentially useful ground water and all surface waters are
protected against degradation. The standards also require a reasonable
expectation that the disposal methods will be effective for at least one
thousand years.
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b. Cleanup of Contaminated Open Land and Buildings:
The standards require cleanup of open land contaminated by tailings
when the average radium concentration attributable to tailings exceeds 5
picocuries per gram (pCi/gm). Five pCi/gm is three to five times the
average radium concentration in normal U.S. soil. Soil contaminated by
tailings, however, usually lies in a thin layer on the surface, while the
radium in normal soil occurs throughout its full thickness. Radiation
from land that satisfies the standard will be within the normal variations
among undisturbed land areas.
2. Summary of Environmental Impacts
EPA estimates that implementing the disposal standards at all
designated sites would prevent about 200 premature deaths per century from
radiation-induced lung cancer for as long as the standards apply. We
further require a reasonable expectation that the standards will be
satisfied for at least one thousand years. About 140 of the 200 deaths
would be expected in the populations within 50 miles of the inactive
tailings piles and the rest in the remaining continental U.S. population.
Health effects from contaminated ground water are not included in the
above estimate.
Estimates of health improvements from implementing the cleanup
standards have not been made. Such benefits would include not only pre-
venting adverse health effects, but also reclaiming contaminated lands
currently unfit for unrestricted use.
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We have estimated the costs of implementing the standards. For an
average inactive uranium mill tailings pile, meeting the disposal standard
will cost from 1 million (1978) dollars to over 13 million (1978) dollars,
depending on the methods used. In a previous cleanup program for buildings
authorized by Congress in 1972 under PL 92-314, cleanup cost about 13,500
(1978) dollars for a residential structure and about 38,500 (1978) dollars
for a commercial building. The probable total cost of the cleanup and
disposal programs under PL 95-604 will be 200 million (1978) dollars to
300 million (1978) dollars. These expenditures could benefit the local
economies, and should have no perceptible effect on the national economy.
3« Alternat iyes Considered
With regard to the form and content of the standards, we considered
the following major alternatives:
a. Disposal Standards:
Uncontrolled uranium mill tailings endanger people and the
environment —
o By releasing radon-222, a radioactive gas, into the atmosphere,
where it and its radioactive decay products can be breathed;
o By supplying a source of windblown radioactive particles;
o By exposing people who live or work near the tailings to direct
gamma radiation; and
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o By releasing radioactive and nonradioactive contaminants to
surface or ground water through erosion or leaching.
Generally applicable standards to protect the environment and the
public's health and safety must be based on the reasonableness and feasi-
bility of controlling these potential hazards. Because of the long
lifetimes of the radioactive contaminants and the presence of such perma-
nently toxic nonradioactive contaminants as arsenic and lead in tailings
material, the longevity or permanence of control methods must be
considered.
The principal health hazard is release of radon-222 into the
atmosphere. We conclude that techniques which control radon releases
reasonably well and have lasting effectiveness will essentially control
airborne particles and direct gamma radiation completely. The standards,
therefore, do not specifically address these letter two hazards, and the
following discussion of control alternatives is restricted to radon-222
releases and water. This section also discusses alternative longevity
requirements for controls.
(1) Radon Control
We considered alternatives for limiting radon that ranged from no
control (the existing condition) to essentially complete control (pre-
venting almost all radon release). We also explored middle alternatives
to control radon release to various degrees down to about the normal
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background level. We compared all three alternatives for costs, benefits,
feasibility, longevity, and other factors.
We rejected the concept of no control, because people living near
uncontrolled piles would clearly have a higher risk of radiation exposure.
Radon emissions, moreover, would convey a health hazard over long
distances and for long periods.
We rejected the concept of essentially complete radon control, because
it may be impractical and would provide a small added reduction in overall
risk at relatively high cost.
The proposed disposal standards, therefore, limit radon releases from
tailings piles to be within the range of variation found in normal soils.
(2) Water Contamination
Alternatives for limiting water contamination range from no
additional control (the existing condition) to complete prevention. We
examined these and a middle ground: limiting contamination to a degree
comparable to other water quality programs.
We concluded that some control is warranted. The potential effects
of uranium mill tailings on surface and ground water quality vary
considerably from site to site, and under some conditions ground water
could become unusable over an area much larger than the pile. The
likelihood that this will happen has not been thoroughly examined.
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Available information suggests that special measures to protect
ground water often will be unnecessary. Where the standards might be
exceeded only immediately near a pile, moreover, we believe that the
substantial disruptions and cost needed to avoid the violation would be
unwarranted.
We therefore propose to apply ground water standards only within one
kilometer from the pile when an existing site is used for disposal, and
within 0.1 kilometer at new disposal sites.
The standards provide that tailings disposal will not cause ground
water contaminants to exceed specified levels. If the ground water
already exceeds these levels for reasons other than tailings, no further
degradation is allowed. Where ground water contamination has already
occurred, it may sometimes be possible to reduce it, but requiring remedial
actions to satisfy pre-set standards in every case is not practical. The
proposed ground water standards therefore do not apply to materials
already released from the tailings. Using their authorities under
PL 95-604, however, we expect other Federal agencies to take practical
actions at sites where they are needed to avoid harm from such materials.
The radon release and ground water protection standards should protect
surface water adequately. As assurance, however, we propose to require
that surface water not be degraded by tailings after disposal of the piles.
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(3) Length and effectiveness of controls
The health protection the disposal system ultimately affords depends
on the degree of control and the time over which control is maintained.
Requirements could range from a few years to as long as the tailings
remain potentially hazardous. We considered the technical and economic
aspects of various control periods.
Congress recognized that uranium mill tailings represent long-term
hazards, and directed EPA to set reasonable standards for their long-term
disposal. We propose to require a reasonable expectation that the radon
emission and water protection standards for tailings disposal will be
satisfied for at least one thousand years. Institutional controls, such
as record keeping, maintenance, and land-use restrictions, can provide
greater protection than the standards require, but they are unreliable as
the primary control over one thousand years. Though institutional
controls can be helpful, physical disposal methods are necessary.
Pragmatism suggests the choice of a thousand-year period, though
technically and economically reasonable disposal methods may, for some
tailings piles, afford even longer protection. A thousand-year standard
reflects our judgment that the disposal standards must be practical for
all the inactive sites. It does not mean that we care little for the
future beyond one thousand years.
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b. Cleanup Standards:
Uranium mill tailings from inactive sites have been spread near and
far by wind, water, and people. Therefore, standards for cleanup must
address the following situations:
o Tailings have spread different distances from different piles,
are found at various depths in the soil, and are mixed with various
materials. The standards must therefore specify the quantity or
concentration of tailings which requires cleanup.
o Radioactive elements leach out of tailings piles into the subsoil
beneath. The standards must therefore specify the permissible level of
radioactivity in the subsoil, should the pile covering it be removed.
o Tailings used a landfill or made into building materials or which
accumulate around a structure are particularly hazardous. The exchange of
air between a building's interior and the outdoors is limited, so indoor
concentrations of radon decay products may be many times the outdoor
levels. The standard must therefore specify the maximum allowable concen-
tration of radon decay products inside buildings. The cleanup standard
for open land must consider the possibility of future construction.
The level of radon decay products in a building is related, among
other things, to the concentration of radium, present naturally or as a
contaminant, in the underlying or adjacent soil. So many other factors
arise, however ~ the rate at which air is exchanged between indoors and
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outdoors, for example — that strictly correlating the interior level with
the radium in the soil is difficult. Radium concentrations from 1 to
5 pCi/gm in soil, a range whose lower end is common among natural soils,
can produce indoor levels of radon decay products greater than 0.01 WL.
Natural or contaminated soils with radium concentrations of 5 pCi/gm
through a depth of several feet can also produce gamma radiation exposure
rates of about 80 mR/yr. Exposure rates are proportionately higher or
lower for other radium concentrations, decreasing as the layer of radium-
containing material becomes thinner or is covered over by other materials.
The proposed standard requires that for any open land contaminated
with tailings, the average radium concentration in any five-centimeters-
thick layer within one foot of the surface, or any 15 cm layer below one
foot, shall not be more than 5 pCi/gm after cleanup. The proposed standard
is EPA1s judgment of the most stringent cleanup condition that may reason-
ably be required for all the inactive mill sites. After the required
cleanup, radon emission and gamma radiation from the site will be within
the normal variations that occur among nearby undisturbed land areas.
Exposure even to normal concentrations of indoor radon decay products
carries some health risk, but we believe Congress intended that tailings
should not unreasonably increase this risk. Concentrations of indoor radon
decay products in normal buildings, however, vary widely, and depend on
many factors. Of the alternative forms for a remedial action standard for
indoor radon decay products, we decided that limiting the total
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concentration is the only workable form. We believe that the proposed
remedial action level of 0.015 WL (including background) for occupied or
occupiable buildings is the most protective level that can be justified.
Experience in a cleanup program in Grand Junction, Colorado, and studies
performed by EPA for homes in Florida indicate that remedying concentra-
tions greater than 0.015 WL usually is practical. We have concluded from
studies of radon decay product concentrations in normal houses that efforts
to reduce levels significantly below 0.015 WL by removing tailings would
often be unfruitful and would waste the money spent.
The proposed limit is based on the hazard from breathing indoor air
containing radon decay products. Gamma radiation, however, can penetrate
the body from the outside. We expect that the indoor radon decay product
standards generally will be met by removing tailings from under and around
the building; this will eliminate any indoor gamma radiation problem. For
some buildings, however, removing the tailings may be impractical, more
for engineering reasons than because of cost. Cleaning the air, improving
ventilation, and sealing the walls and floors are alternatives, but if
these methods are used, standards will be needed to limit the occupants'
exposure to gamma radiation.
If the gamma radiation standard is too lenient, methods other than
removal of tailings could be used more often. Because removal is defini-
tive and its effectiveness long lasting, however, it is the remedial
method we wish most to encourage. To this end, our proposed action level
for gamma radiation, 0.02 mR/hr above background, allows some limited
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flexibility in the methods chosen to reduce indoor radon decay product
concentrations. Reducing the standard much below 0.02 mR/hr would
virtually eliminate this flexibility and provide only a small additional
health benefit to a few individuals.
The proposed standards will be implemented by the Department of
Energy, with the concurrence of the Nuclear Regulatory Commission and in
cooperation with other Federal agencies, affected States, and Indian
tribes. Because the proposed standards probably will not fit exceptional
circumstances, we have provided criteria for determining when exceptions
to the standards are justified. In such cases, DOE, with the concurrence
of NRC, may select and perform remedial actions which come as close to
meeting the standards as is reasonable.
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1: INTRODUCTION
In Public Law 95-604, the Uranium Mill Tailings Radiation Control Act
of 1978 (42 USC 7901), the Congress found that uranium mill tailings at
active and inactive mill operations may pose a potential and significant
radiation health hazard to the public, and that every reasonable effort
should therefore be made to stabilize, control, and dispose of such
tailings in a safe and environmentally sound manner to prevent or minimize
radon diffusion into the environment and other environmental hazards from
tailings.
The Act specifically calls for EPA to set generally applicable
standards for both radiological and nonradiological hazards posed by
"residual radioactive materials" at certain inactive uranium mill tailings
sites and at other sites where such materials are deposited. "Residual
radioactive material" is (1) tailings waste remaining after uranium and
other products are extracted from ore and judged radioactive by the
Secretary of Energy, and (2) other waste connected with the extraction
process, including unprocessed ore and low-grade material, judged
radioactive by the Secretary of Energy.
The Act also requires EPA to set generally applicable standards for
active uranium mill and disp'osal sites. The standard discussed in this
Environmental Impact Statement does not address active sites. We will
propose such a standard later. Our current proposal sets standards for
cleaning up open lands and structures contaminated with residual
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radioactive material — mainly tailings or similarly hazardous wastes —
control; and for controlling uranium mill tailings from inactive
processing sites for a long time.
The Uranium Mill Tailings Radiation Control Act of 1978 (PL 95-604)
names 22 inactive processing sites. Twenty-one are inactive uranium mill
sites in the western United States, and the other is the location of a
former rare-metals processing plant in Canonsburg, Pa. This Environmental
Impact Statement primarily applies to the mill sites but also addresses
the Canonsburg site, for its potential hazards and many of the methods to
correct and control them parallel those of the other sites.1
In developing the proposed standards, we first evaluated the potential
effects on public health and the environment of tailings at the designated
sites. We then reviewed general approaches to controlling these effects
and developed cost estimates for specific control methods. Our proposed
control standards were based on such factors as improved health; longevity
of control methods; limitations of institutional cost; feasibility, and
the potential impact of the control methods themselves. Under PL 95-604,
1 The Department of Energy formally designated the 22 sites in accord
with Sec. 102 of PL 95-604. It also has identified and designated three
other processing sites that require remedial action. These are located
near Bowman and Belfield, North Dakota, and Baggs, Wyoming. These three
sites have only recently been studied, and they appear to be among the
least hazardous in the entire group (see "Uranium Mill Tailings Site Visit
and Preliminary Health Impact Evaluation," a report prepared by Ford,
Bacon and Davis Utah, Inc., October 17, 1979). Data on them is much less
complete than for the other designated sites, so we have omitted them from
our analysis. We believe that their omission has little effect on our
conclusions.
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the Department of Energy, the affected States, and the Nuclear Regulatory
Commission are responsible for implementing the standards.
In this Draft EIS, Chapter 2 summarizes the history of the uranium
milling industry and briefly surveys the designated sites. Chapter 3
reviews their radiological and nonradiological characteristics and
discusses off-site contamination of nearby land and buildings. Chapter 4
outlines the potential health hazards posed by uranium mill tailings with
estimates of the risks to people living nearby, in the region, and in the
continental United States. Chapter 5 examines alternative degrees of
control. Chapter 6 presents monetary cost estimates for various
engineering approaches and discusses such other significant control
factors as duration, effectiveness, and occupational hazards. Chapter 7
addresses off-site contamination and factors weighed in cleaning up
contaminated land and structures. Chapter 8 explains how we chose the
proposed standards. Chapter 9 discusses the process of implementing the
standards, and the anticipated effects.
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2: URANIUM MILLING OPERATIONS
2.1 History of Uranium Milling Operations
A brief history of uranium milling appeared in the Nuclear Regulatory
Commission's Draft Generic Environmental Impact Statement (NR 79). The
history summarized two papers by Merritt (ME 71) and Facer (FA 76) and,
for its relevance to this report, is repeated here.
In the past 35 years the uranium industry has undergone a series
of transformations, the element changing almost overnight from a
commodity of only minor commercial interest to one vital for
nuclear weapons and, now, to its important peaceful use as a fuel
for generation of electrical energy. With each change there has
been a surge of interest in ore exploration and development, and
in new and expanded production facilities.
The military demand for uranium beginning in the early 1940s had
to be met from known sources of supply. The rich pitchblende
ores of the Shinkolobwe deposit in the Belgian Congo and the
Great Bear Lake deposit in Canada supplied uranium during the war
years and were supplemented by production from treatment of old
tailings dumps and a few small mines in the Colorado Plateau
area* These high-grade ores and concentrates were refined by an
ether extraction technique adapted from analytical procedures.
Crude ore milling processes for low-grade ores used during this
period reflected little change from methods used 40 years earlier
(at the turn of the last century) with uranium recovery from the
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leach solutions based on several stages of selective
precipitation. Milling costs were high and overall recovery was
low, as judged by current standards.
With passage of the Atomic Energy Act of 1946, a strong emphasis
was placed on the discovery and development of new worldwide
sources of uranium. At the same time, the research efforts begun
earlier were expanded in scope and magnitude to advance the
process technology. These efforts led to greater use of lower
grade ores than previously had been considered feasible, such as
the uranium-bearing gold ores in South Africa, as a source of
uranium, and to the discovery and developemnt of large, low-grade
deposit in the Beaverlodge, Elliot Lake, and Bancroft regions of
Canada.
In the United States, prospecting and mining for uranium were
encouraged by the Atomic Energy Commission (AEC) through
guaranteed fixed prices for ore, bonuses, haulage allowances,
establishment of ore-buying stations and access roads, and other
forms of assistance. These incentives led directly to an
increase in the known mineable reserves of ore in the western
United States from about 9 x 105 metric tons (MT) (1 x 106
short tons (ST)> in 1946 to 8.1 x 10? MT (8.9 x 107 ST) in
1959. Programs also were initiated to examine other possible
sources of uranium and to develop methods for processing these
materials. AEC purchases from 1948 through 1970 totalled
2-2
-------
approximately 3 x 105 MT (3.3 x 105 ST) of U30g of wh£ch
nearly 1.6 x 105 MT (1.8 x 105 ST) with a value of about
$3 billion were supplied from domestic sources.
During the peak production years in the United States, from 1960
through 1962, the number of operating mills (excluding plants
producing by-product uranium from phosphates) varied from 24 to
26, with total annual production exceeding 1.5 x 104 MT
(1.7 x 104 ST) of U30g from the treatment of about
7 x 106 MT (8 x 106 ST) of ore.
In 1957, it was apparent that very large ore reserves had been
developed, and that additional contracts, which were the main
incentive for exploration by potential producers, would lead to
commitments exceeding government requirements through 1966. In
1958, the AEC withdrew its offer to purchase uranium from any ore
reserves developed in the future. This led to shutdowns of mills
after expiration of contracts and to stretching out of deliveries
under long-term contracts in the United States, Canada, and South
Africa.
Total production of U30g through 1977 from U.S. sources is
estimated at about 2.7 x 105 MT (3 x 105 ST). The amounts of
ore used in the production of this U30gj flnd the approximate
amount of tailings produced, were expected to reach 1.3 x 108
MT (1.4 x 108 ST) by the end of 1977. Of this total, about
2-3
-------
20%, or 2.3 x 107 MT (2.5 x 107 ST), is located at inactive
mill sites and the balance (80%) is located at currently active
mill sites.
Nuclear power's growth in the 1970's and projections of the future
need for nuclear fuel spurred increased exploration for ore and
construction of mills in the last part of the decade.
2.2 Status of Milling Sites
Table 2-1 shows the number of active and inactive uranium milling
sites in the United States at five-year intervals. This listing omits
several pilot facilities that produced uranium before 1950.
The hazards posed by mill tailings were incompletely recognized in the
uranium industry's early years, and, while the Atomic Energy Act of 1954
instituted licensing of mill operators, tailings remained free of controls.
Numerous studies have assessed tailings hazards, and several State and
Federal agencies — Colorado's, for example — have acknowledged a need for
controls. But no comprehensive program to control tailings began until
after the Subcommittee on Raw Materials of the Joint Committee on Atomic
Energy conducted Congressional hearings in 1974. Studies supported by the
Energy Research and Development Administration (later merged into the
Department of Energy) then followed. The first set of studies (the Phase
I studies) determined the current status and general scope of the hazards
at inactive mill tailings sites. The second set (the Phase II studies)
2-4
-------
TABLE 2-1
Number of Active and Inactive Uranium Mill Sites
(a)
Year No.
Up thru 1940
1945
1950
1955
1960
1965
1970
1975
1980 (Jan)
of Active Sites
4
5
9
12
30
21
15
15
2Kb)
No. of Inactive Sites
0
1
1
2
4
13
20
24
25
Total
4
6
10
14
34
34
35
39
46(b)
References JO 77, AU 70, and TH 79.
included are 8 solution mining operations, 4 phosphoric acid
by-product plants, and 4 heap leaching operations.
2-5
-------
assessed them in greater detail and discussed various alternatives for
controlling them.
2.3 The Inactive Sites
The Congressional hearings noted above took place on March 12,
1974. The bills discussed, S.2566 and H.R. 11378, were identical. They
proposed that the U.S. Atomic Energy Commission (later the Energy Research
and Development Administration and now the Department of Energy) and the
State of Utah jointly assess and act appropriately to limit people's
exposure to radiation originating from the Vitro uranium mill tailings
site at Salt Lake City, Utah.
EPA endorsed the bills' objectives but, with AEC, recommended
instead that the two agencies, in cooperation with the states, assemble
comprehensive studies of all inactive mill sites. The studies would be
divided into two phases. The Phase I studies would establish the sites'
condition, ownership, surroundings, and the need, if any, for more
detailed studies. The Phase II studies would, as needed, evaluate the
hazards and analyze alternative solutions and their costs. Congress
accepted the proposal, and in May 1974 the Phase I studies began.
2'3-1 The Phase I Studies
The Phase I studies conducted during 1974 summarized conditions
at 21 inactive uranium milling sites (See Table 2-2) and outlined the
detailed engineering assessments to be performed in Phase II.
2-6
-------
TABLE 2-2
Inactive Mill Sites
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
Site
ARIZONA
Monument Valley
Tuba City
COLORADO
Durango
Grand Junction
Gunnison
Maybe 11
Naturita
New Rifle
Old Rifle
Slick Rock (NC Site)
Slick Rock (UC Site)
IDAHO
Lowman
NEW MEXICO
Ambrosia Lake
Shiprock
NORTH DAKOTA
Belfield
Bowman
OREGON
Lakeview
PENNSYLVANIA
Canonsburg (a)
SOUTH DAKOTA
Phase I
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Phase II
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
x(b)
Designated under
PL 95-604
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
TEXAS
20. Falls City x
21. Ray Point x
(continued)
2-7
-------
TABLE 2-2 (continued)
Inactive Mill Sites
Designated under
Site Phase I Phase II PL 95-604
22.
23.
24.
25.
26.
27.
28.
29.
UTAH
Green River
Hite(e)
Mexican Hat
Monticello (f)
Salt Lake City
WYOMING
Baggs
Converse County
Riverton
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Totals 21 23 25
(a) Former rare-metals plant; not an inactive uranium mill site
(b) Study done as part of Formerly Utilized MED/AEC Sites Remedial
Action Program
(c) Owned by TVA
(d) Uranium not sold to U.S. Government
-------
The Phase I studies excluded several sites: Monticello, Utah
(owned by the Department of Energy); Edgemont, South Dakota (owned by
the Tennessee Valley Authority); Kite, Utah (covered by Lake Powell, a
lake created by the 1963 construction of the Glen Canyon Dam after
high-grade tailings were removed from the site); Riverton, Wyoming
(licensed by the AEC to a private owner at the time of the Phase I
studies but later added to the Phase II studies); and Bowman and
Belfield, North Dakota, Baggs, Wyoming, and Canonsburg, Pennsylvania.
As a sample of the Phase I studies, the following excerpts from the
Phase I Summary discuss the Vitro site at Salt lake City, and
stabilization, off-site radiation, and the use made of inactive mill
sites.
The Vitro Sitej, Salt Lake City
The existing conditions at the Vitro site in Salt Lake City are
completely unsastisfactory. The tailings pile, located at the
center of population of Salt Lake valley, is largely uncovered
and subject to continuing wind and water erosion. While the
extent of exposure of the population to radiation from this
source may be difficult to quantify, the spread of radioactivity
is readily detectable for considerable distances offsite.
Because of the continued industrial growth in the area, the
population exposure can be expected to increase. The site is
only partially fenced and is readily accessible to the public.
If the tailings pile were to be stabilized by covering and
2-9
-------
vegetation at the present site, their integrity would be
difficult to maintain. While contamination of surroundings from
blowing dust could be reasonably well controlled, the emanation
of radon gas and leaching of radium into ground waters would be
expected to continue. The representative of AEC, EPA and the
State of Utah concur that the present site is unsuited to
long-term radioactive tailings storage, and the Phase II study of
the Vitro site should be directed principally toward a plan for
removal to a more suitable location.
Stabilization
The conditions found at the 21 mill sites are summarized in
(Table 2-3). Tailings stabilization at six sites had not been
attempted at all. However, following the site visit, the State
of Oregon notified the owner that stabilization should be under-
taken as soon as possible at Lakeview. The chemical surface
coating used at Tuba City, Arizona, has broken up after only a
few years weathering and is considered unsuccessful. The
conditions at Shiprock, New Mexico, on the Navajo Reservation
have been considerably aggravated as a result of the operation of
a heavy earth-moving-equipment school on the site. The State of
Colorado adopted regulations in 1966 for stabilization and control
of uranium mill tailings by the mill owners. The substantial
efforts made in that state have been fairly successful. In no
case, however, was it found that the results could be considered
entirely satisfactory. Some erosion and loss of cover was noted
2-10
-------
TABLE 2-3
SUMMARY OF CONDITIONS NOTED AT TIME OF
Condition
of
Tailings
ARIZONA
Monument Valley
Tuba City
COLORADO
Durango
Grand Junction
Cunnison
Maybell
Katurita (a)
Nev Rifle
Old Rifle
Slick Rock (NC)
Slick Rock (DC)
IDAHO
Lowman
NEW MEXICO
Ambrosia Lake
Shiprock
OREGON
Lakeview
PENNSYLVANIA
Canonsburglb )
TEXAS
Falls City
Ray Point
UTAH
Green River
Mexican Hat
Salt Lake City
WYOMING
Converse City
U
H
P
S
S
S
S
P
S
S
S
U
0
P
V
U
P
P
S
U
U
U
Condition of
Buildings
& Structures
on Millsite
R
PR-UO
PR-UO
PR-0
B-0
R
PR-0
M-0
PR-OU
R
R
R
PR-0
PR-0
M-OU
B-O
M-OU
M-OU
B-O
B-O
R
R
Mill
Housing
N
E-0
N
N
N
N
E-P
N
N
N
E-P
N
N
E-0
N
N
N
N
N
E-0
N
N
PHASE I
Adequate Property
Fencing, Bounded by
Posting, & River or
Surveillance Stream
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
Yes
Yes
No
No
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
Ho
Yes
No
No
No
No
Yes
No
SITE VISITS
Dwellings &/or
Industry
Within 1/2
Mile
Yes
Yes
Yes
Yes
Yes
No
No
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
No
No
Yes
Yes
Yes
No
Possible Tailings
Visual Evidence Ground &/or Removed From Other
Wind &/or Water Surface Water Site for Hazards
Erosion Contamination Private Use On-Site
No
Yes
Yes
No
No
No
Yes
Yes
No
Yes
No
No
Yes
No
Yes
Yes
No
No
Yes
Yes
Yes
No
No
No
No
No
Yes
No
Yes
Yes
Yes
No
No
No
No
No
No
No
No
Yes
Yes
No
No
No
No
Yes
No
No
Yes
No
Yes
No
No
Yes
Yes
No
No
No
No
No
No
No
No
No
No
Yes
No
Unknown No
Yes
No
Yes
Yes
Yes
No
No
No
No
No
Yes
No
No
No
No
No
Yes
No
(Continued)
-------
TABLE 2-3 (continued)
Column 1. S - Stabilized, but requires improvement Column 2. M - Mill intact Column . - one
P - Partially stabilized B - Building(s) intact E - "astiag
U - UnstabilUed * - «"! ^d/or buildingB removed O - Occupxed
PR - Hill and/or buildings partially removed P - Part occupied
0 - Occupied or used
00 - Unoccupied or unused
(*) Pile moved to new location after this study.
(b) Sot in Phase I, but information included for completeness
ro
i—1
ro
-------
in all cases, and the vegetation was generally not self-sustaining
without continued maintenance, usually including watering and
fertilization. Thus, the stabilization work done to date
represents a holding action, sufficient for the present, but not
a satisfactory answer for long-term storage.
Offsite Radiation
The mechanisms known to cause spread of radioactivity from the
sites are:
1. Windblown solids.
2. Radon gas and its decay products.
3. Deliberate removal of tailings and other materials for
offsite use.
4. Water erosion and dissolution.
5. Ground water and soil contamination.
In addition, low grade ores and mine wastes have occasionally
been spilled or dumped offsite.
Evidence exists of all these mechanisms causing some degree of
increase in radioactivity above natural background. In no other
location was there evidence of the widespread use of tailings in
building construction such as occurred in Grand Junction,
Colorado, Nevertheless, there are some habitable structures in
several other locations where tailings use is suspected.
2-13
-------
Measurements of dust concentrations in air made near tailings
piles in the past have not indicated significant hazard from
inhalation. However, the significance of blowing dusts settling
out in the general vicinity over a period of many years has not
been thoroughly evaluated.
The EPA has held the position for some time that radon gas
emanating from a tailings pile may cause a detectable increase in
airborne radiation levels in the vicinity of a tailings pile,
roughly within half a mile. The gas will diffuse readily into
existing structures, but its particulate decay products would
tend to .remain inside, possibly causing a buildup in radioactivity
within the structure. There is little data available to support
this hypothesis, but it needs to be checked carefully, as it could
have significant bearing on decisions regarding removal of
tailings piles from populous areas. High radon decay product
levels were found in structures close to the Vitro pile, but the
possibility of their having been built over tailings has not been
excluded.
Water erosion does not appear to have been a significant factor
in the off site migration of tailings. However, the movement of
radium and soluble salts into the sub-soil in areas with high
water table needs further evaluation. In a few locations tailings
piles are located near water courses where flooding can be a
problem.
2-14
-------
Use of Mill Sites
Where housing and other structures remain from the milling opera-
tions they have been frequently put to use. Housing at Tuba City,
Naturita, Slick Rock, Shiprock and Mexican Hat is occupied.
Buildings on the mill sites at Gunnison, Naturita, Shiprock, Green
River and Mexican Hat are being used for warehousing, schools and
other purposes. At several sites, buildings are still used for
company activities. At Salt Lake City a sewage disposal plant is
operating on the site. Construction of an automobile race track
was begun in the middle of the tailings pile. It was subsequently
stopped by the State upon recommendations of AEC and EPA. The
pressure for use of sites in urban areas is likely to increase
with time consistent with projected population growth. None of
the areas formerly occupied by milling facilities, ore stockpiles,
etc., have been examined to determine the depth of soil contamin-
ation, or suitability for future unrestricted use.
Table 2-3 summarizes the widely varying conditions at the time of the
Phase I site visits (AE 74, Table I). Table 2-4 summarizes the Phase I
studies and presents the recommendations made for Phase II studies of
potential remedies for each site (AE 74, Table II).
Since the Phase I studies, the Naturita pile has been moved and the
Shiprock site has been cleaned up and the pile stability improved.
Tailings from the Monument Valley, Falls City, and Ray Point sites have
been removed and used as construction material. At some sites buildings
2-15
-------
TABLE ?-4
SUMMARY OF PHASE I FINDINGS AND PRINCIPAL ACTION TO BE STUDIED IN PHASE II
ro
Arizona
Monument Valley
Tuba City
Colorado
Durango
Grand Junction
Gunnison
Maybell
Naturita
New Rifle
Old Rifle
Slick Rock (NC)
Slick Rock (DC)
Idaho
Lawman
Hew Mexico
Ambrosia Lake
SMprock
Oregon
Lakeview
Texas
Falls City
Ray Point
Years Operated
1955-67
1956-66
1943-63
1951-70
1958-62
1957-6A
1939-63
1958-72
1924-58
1931-43
1957-61
1955-60
1958-63
1954-68
1958-60
1961-73
1970-73
Tons of Tai lines
(in thousands)
1,200
800
1,555
1,900
540
2,600
704
2,700
350
37
350
90
2,600
1,500
130
2,500
490
AS DETERMINED BY AEC
Ra in Ci I
50
670
1 , 200 X
1,350 X
200 X
640
490
2,130 X
320 X
30
70
10
1,520
950 X
50
1,020
230
(NOW DOE)
IX
X
X
X
X
X
X
X
X
X
X
K
X
X
X
X
III IV V
X
XXX
X X
X X
X
X
X
X
X X
X
X
X X
X X
X X
VI
X
X
X
X
VII
X
X
(Continued)
-------
TABLE 2-4 (continued)
SUMMARY OF PHASE I FINDINGS AND PRINCIPAL ACTION TO BE STUDIED IN PHASE II
AS DETERMINED BY AEC (NOW DOE)
Utah
Green River
Mexican Hat
Salt take City
Wyoming
Converse County
Totals
Years Operated
1958-61
1957-65
1951-68
1962-65
Tons of Tailings Ra in Ci I II III
123
2,200
1,700
187
25,256
20 XX
1,560 X X
1,380 XXX
60
13,950
IV
X
X
Notes:
I - The removal of tailings and other radioactive materials from the site to a more suitable location.
II - Stabilize tailings or complete or improve stabilization to prevent vind and water erosion.
Ill - Decontamination of millsite or immediate area around tailings pile.
IV - Complete or improve fencing and posting of millsites and tailings areas.
V - Determine levels of radioactivity in structures where tailings may have been used in construction and
determine costs and measures needed for remedial action vhere warranted.
VI - Conduct ground water surveys in immediate area of millsite and tailings.
VII - No phase II study proposed at this time.
VI VII
-------
and other architectural features, such as fences, have changed; all
buildings have been removed at the Shiprock site, for example. And wind
and water have eroded tailings at all of the sites.
2.3.2 The Phase II studies
The Phase II studies (FB 76-78) of 23 sites (Table 2-2) began in 1975.
The studies fixed site ownership and determined hydrologic, meteorologic,
topographic, demographic, and socioeconomic characteristics of the inactive
mill sites and alternative sites to which tailings might be moved. Radio-
logical surveys of air, land, and water near the tailings sites included
estimates of exposures to individuals and nearby populations and identifi~
cation of offsite use of tailings. Finally, the studies developed
alternative remedial action plans for each site and analyzed each plan's
cost.
The scope of the Phase II studies at each site was guided by the recom-
mendations of the Phase I studies (Table 2-4). This Environmental Impact
Statement incorporates many of the results of these studies, but the
Phase II reports themselves offer more detailed, site-specific information.
2-18
-------
References for Chapter 2
(AE 74) U.S. Atomic Energy Commission, 1974, "Phase I Studies of Inactive
Uranium Mill Sites and Tailings Piles" (Summary and individual
site reports).
(AU 70) Augustine, R.J., August 1970, "Inventory of Active Uranium Mills
and Tailings Piles at Former Uranium Mills," ISDHEW.
(FA 76) Facer, J.F., Jr., "Production Statistics" (of the Uranium
Industry), presented at Grand Junction Office Uranium Industry
Seminar, Department of Energy, October 1976.
(FB 76-78) Ford, Bacon, and Davis, Utah, Inc., "Phase II—Title 1,
Engineering Assessment of Inactive Uranium Mill Tailings," 20
contract reports for Department of Energy Contract No.
E(05-l)-1658, 1976-78.
(JO 77) Jones, J.Q-, October 1977, "Uranium Processing Developments,"
Grand Junction Office, Department of Energy.
(ME 71) Merritt, R.C., 1971, "The Extraction Metalurgy of Uranium,"
Colorado School of Mines Research Institute, Golden, Colorado.
(NR 79) U.S. Nuclear Regulatory Commission, "Generic Environmental Impact
Statement on Uranium Milling," April 1979, NUREG-0.511.
(TH 79) Personal conversation with John Themelis, October 1979, Grand
Junction Office, Department of Energy.
2-19
-------
3: SOURCE TERMS
3.1 Introduction
In assessing the potential health and environmental impact of the
tailings, the "source terms" that is, the amounts and concentrations of
radioactivity and toxic chemicals in the tailings piles and in off-site
contamination — are particularly important. This section discusses these
sources.
3.2 Radioactivity Source Terms
From 1948 through 1978, nearly 157 million tons of ore were processed
at all uranium mills (DO 79), yielding some 328,000 tons of UjOg, a
uranium-rich compound called "yellowcake." Chemicals added in processing
become part of the tailings, so the tailings solids and the ore weigh about
the same. The 22 inactive sites designated under PL 95-604 contribute
about one-sixth of all tailings, or about 26 millions tons, deposited in
piles covering about 1,000 acres (Table 3-1). The remaining tailings are
at active sites licensed by the NRC or Agreement States, and will be
subject to forthcoming EPA standards.
Most of the mills at the now-inactive sites used acid solvents to
dissolve uranium out of the ore. All mills discharged a mixture of solid
tailings and liquids to an impoundment area, unusually referred to as a
tailings pond or tailings pile. Part of the liquid was recycled to the
mill but most of it evaporated or seeped into the ground. Seepage of
-------
TABLE 3-1
RADIOACTIVITY IH TRACTIVE URAHIUM MILL TAILORS PILES
1.
2.
3.
4.
5.
6.
(0
I
ro
7.
8.
9.
10.
11.
12.
13.
14.
15.
SITE
Arizona
Tuba City,
Arizona
Darango,
Colorado
Grand Janction,
Colorado
Gtmnicon,
Colorado
Maybell,
Colorado
Baenrita,
Colorado
Hew Si fie,
Colorado
Old Rifle,
Colorado
Slick Rock {HC),
Colorado
Slick Rock (DC),
Colorado
Lovaun,
Idaho
Aabrosia Lake,
Dew Mexico
Shiproek,
New Mexico
Lakeviev,
Oregon
TtMS OF
TAUIMGS
(MIU.IORS)
1.2
0.8
1.6
1.9
0.5
2.6
0.7
2.7
0.4
0.04
0.35
0.09
2.6
1.5
0.13
AREA OP
TAILINGS
(ACRES)
30
22
21
59
39
80
23
32
13
19
6
5
105
72
30
AVERAGE
ORE GRADE*1*
0.04
0.33
0.25
0.28
0.15
0.098
0.30
0.31
0.36
0.28
0.245
0.19
0.23
0.25
0.15
AVERAGE
RADIUM-226(2)
(pCi/8)
50
924
700
' 784
420
274
800
868
1,008
784
686
532
644
700
420
AHHOAL RADOH
RELEASE
(Ci/yr)
200
2,600
1,900
5,900
2,100
2,800
2,300
3,600
1,700
1,900
500
300
8,600
6,400
1,600
TOTAL
SADIBM-226***
(Ci)
50
670
1,200
1,350
200
640
490
2,130
320
30
70
10
1,520
950
50
MAX. MEASURED
RADIOM-226<5)
(pCi/g>
1,300
1,880
1,800
1,800
1,100
600
1,2OO
1,900
5,400
350
120
244
900
4,000
420
RADOR-222: MEASURED
RELEASE RATE
(pCi/m2-«ec)
14-29
11-406
35-312
25-656
476
75-99
763-2,540
70-1,400
210-1,300
4-246
6-24
50-150
40-300
53-157 f7l
(440-1200-2200)'' "
187-710ra)
-------
TABLE 3-1 — Continued
RADIOACTIVITY IN INACTIVE URANIUM MILL TAILINGS PILES
TOTAL
SITE
TONS OF AREA OF AVERAGE AVERAGE ANNUAL RADON
TAILINGS TAILINGS ORE GRADE(1) RADIUM-226(2) RELEASE(3)
MAX. MEASURED
RADIUM-226W RADIUM-226<5)
(MILLIONS) (ACRES)
(pCi/g)
(Ci/yr)
(Ci)
(pCi/g)
RADON-222: MEASURED
RELEASE RATE
(pCi/m -sec)
to
I
co
16. Canonsburg,
Pennsylvania 0.4
17. Falls City,
Texas 2.5
18. Ray Point,
Texas 0.49
19. Green River,
Utah 0.12
20. Mexican Hat,
Utah 2.2
21. Salt Lake City,
Utah 1.7
22. Converse County,
Wyoming 0.19
23. Riverton,
Wyoming 0.9
18
146
47
9
68
100
5
72
0.16
0.185
0.29
0.28
0.32
0.12
0.20
448
518
812
784
896
336
560
8,400
3,100
900
6,800
11,500
200
5,100
1,020
230
20
1,560
1,380
60
544
4,200
160
264
220
1,900
2,000
650
1,100
185-296
3-78
427
32-128
16-1,600
1-20(9)
(130-300-650)
190-2,860
51-81
(10)
(6)
(7)
W
(')
(10>
(11)
Phase II Reports (TB 76-78).
Calculated from average ore grade, assuming 700 pCi/g per 0.25%.
Calculated from average radium-226, assuming 1 pCi/m^-sec of radon-222 is released (annual average) for each pCi of radium-226
per gram of tailings.
Phase I summary Report (AE 74).
Phase II Reports (FB 76-78). Value shown is for highest reported soil, sediment, or tailings sample. Tailings were not sampled
in all cases.
phase II Reports (FB 76-78), unless indicated otherwise.
Bernhardt, et al. (BE 75), reported values ranging from 590 to 1,320 pCi/m2-sec for uncovered and 440 to 2,200 pCi/mz-sec for
stabilized tailings.
Bernhardt, et al. (BE 75), reported values for stabilized tailings ranging from 3 to 31 pCi/m2-sec.
Measurements by FBDD are based on a sample of tailings in a barrel, with varying moisture contents.
Bernhardt, et al. (BE 75), reported values for 11 sites ranging from 130 to 650 pCi/mZ-sec , with a median of about 300 pCi/m^-see.
Measurements by Bernhardt indicated overlapping ranges of radon release rates for uncovered and covered (up to several feet) tailings.
EPA-520/1/76-001.
-------
contaminants occured at many sites, the extent depending on the location
and design of the impoundment area. Some of the now-inactive mills
discharged liquid directly into surface streams.
Uranium is the first member of a radioactive "decay series"; in other
words, uranium decays to thorium, which in turn decays to radium, with the
chain ultimately terminating with lead (see Fig. 4-1). Because of a
condition called "secular equilibrium," the radioactivity of each member
of the decay series is the same as that of the parent, uranium-238.
%
The amount of radioactive thorium in the tailings pond liquid at
acid-process mills is much higher than at alkaline-process mills, because
it dissolves readily in acid solvents but not in alkaline solvents. About
5% or less of the radium in the ore is dissolved by either method.
Essentially all of the dissolved thorium, radium and radionuclides other
than uranium are discharged to the tailings pond (SE 75).
The solid portion of the tailings can be divided into coarse sands and
finer slimes. In the acid process, residual uranium and radium content in
the slimes is about twice that in the sands, while thorium content appears
to be about the same in both sands and slimes.
Since uranium is removed in milling, the uranium radioactivity levels
in the tailings are substantially less than the radium radioactivity
levels. Thorium-230 levels in tailings are probably close to those of
3-4
-------
radium-226, though the dominance of either may change within the pile
because of variations in the mill process and any efforts to precipitate
radium in the tailings pond.
The activity of such radium decay products as radon in tailings is
somewhat lower than that of the parent radium, since radon is a gas which
can escape from the pile. Only about 20% or less of the radon produced
from the radium, however, leaves the tailings particles, so 80% or more of
the decay products of radon are formed within the particles (CU 73). The
depth of tailings and cover as well as porosity and moisture content
largely determine how much of the radon leaving the tailings particles is
ultimately released to the atmosphere.
Table 3-1 shows the estimated quantity of tailings, area of tailings,
average ore grade, estimated average radium-226 concentration (based on
average ore grade), annual radon release estimate, total curies(l) of
radium, maximum measured radium concentrations, and limited information on
measured radon-222 release rates. For "upgrader" sites where slimes have
been removed, the average concentration is probably lower than that
estimated from the average ore grade. Green River, Monument Valley, Slick
Rock (UC), and Converse County were upgrader sites. The Naturita mill
operated as an upgrader only for a short period before it was shut down.
curie (Ci) is the basic unit of radioactivity, equal to 37 billion
nuclear disintegrations per second.
3r5
-------
As shown in Table 3-1, the maximum radium concentration found in samples
ranged from about 1/5 to 25 times the average value estimated from the
average ore grade.
3.3 Nonradioactive Contaminants
A number of nonradioactive toxic substances from ore or from chemicals
used in processing have been found in the liquid and solid portions of
uranium mill effluents (SE 75). Information on their concentrations in
tailings and ground water at the inactive sites is part of the Phase II
reports (FB 76-78). The contaminants present in a mill waste stream
depend on the source and type of processing; Table 3-2 gives examples of
the elements and compounds found in a tailings pile at one inactive
alkaline-leach uranium mill. The ratio of the concentration in slimes to
that in a "background" soil sample is included. Uranium and thorium are
radioactive, but are also included in this table. Table 3-3 indicates
additional elements and compounds which have been reported in other
tailings piles.
Ground water has been contaminated at some inactive uranium mill
sites. The primary source of such contamination within the first few
decades after mill operation is the tailings pond water discharged while
the pile is active. Kaufmann, e£ al. (KA 75), estimated that 30% of the
water from two active tailings pond seeped into the ground. Purtyman, et_
al., estimated seepage loss from an inactive pile in New Mexico during its
active life as 44% (PU 77). The NRC DGEIS on Uranium Milling uses a model
which assumes a 38% water loss by seepage (NU 79), and estimates movement
of seepage through unsaturated soil, formation of the seepage bulb in the
-------
TABLE 3-2
Elements and Compounds Measured in an Inactive Tailings
Concentration in
Element Tailings Sands
or Compound (parts per million)
Uranium 211
Molybdenum — (b)
Selenium 31.3
Vanadium
Arsenic
Chlorine
Antimony
Calcium
Cerium
Bromine
Sodium
Iron
Terbium
Cobalt
Aluminum
Barium
Europium
Gallium
Lanthanum
Manganese
Scandium
Zinc
Chromium
Potassium
Thorium
Titanium
Ytterbium
Cesium
Hafnium
Magnesium
Rubidium
Tantalum
Neodymium
Strontium
Tungsten
204
27
ND^C'
0.69
2830
90
2.5
1080
1060
0.37
2.9
4280
663
0.95
5.5
24
335
2.5
15
10
2350
4.6
1330
1.6
2.4
3.6
4190
82
0.42
41
183
0.49
Concentration in
Tailings Slimes
(parts per million)
380
300
133
2050
79
580
2.2
2670
163
7.6
1970
3550
0.63
9.3
6660
572
1.48
44
388
7/\
.0
68
25
2110
8.8
2140
2.9
2.4
4.8
2180
63
0.62
95
ND
ND
Ratio of
Concentration in
Slimes to Background
160
160
100
70
1 O
18
V 1
13
5
2F
.5
2
2
1
1
1
1
*"*""
1
1
i
i
<«> (DR 78)
(b) — indicates no data
ND indicates not detected
3-7
-------
TABLE 3-3
Additional Elements and Compounds Found in Uranium Mill Tailings(a)
Boron Nickel
Cadmium Silver
Copper Zirconium
Gold Cyanide
Lead Silicate
Mercury
(a) (FB 76-78)
3-8
-------
saturated soil zone, and movement of pollutants with the ground water.
For its model mill, in an arid region, the NRC concluded that about 95% of
the possible contamination was associated with the active phase of the
pile and only 5% with the long-term losses from the inactive pile
(NR 79). However, studies by Klute and Heermann (KL 78) indicate that
even in dry climates precipitation can produce a downward flow of water
through the tailings.
Tailings piles at inactive mill sites already have lost much of the
water present when they were formed. The water has evaporated, gone
underground, or run off on the surface. Any future contamination of water
by the pile mainly would result from erosion, rain, flooding, or the
flushing action of seasonal changes in the water table where it intersects
a pile. The quality of streams and lakes could be degraded by seepage
from a pile, or by tailings which run off or are blown into them.
Table 3-4 indicates inactive and active sites where elevated concentra-
tions of nonradioactive contaminants have been found in ground water near
tailings piles.
3.4 Off-Site Contamination
In 1972, EPA and AEC, using a mobile detector in the vicinity of
tailings sites, located areas with higher than normal gamma radiation. To
determine the source, teams from EPA and the State health departments
conducted further gamma surveys. At hundreds of locations, uranium mill
tailings were found under or within 10 feet of structures (FB 76-78) and,
at additional hundreds of locations, more than 10 feet from a structure.
3r9
-------
TABLE 3-M
Elements/Compounds Reported in Elevated Concentrations
In Ground Water in the Vioinity of Tailings Piles
Site
Ambrosia Lake, NM(a)
Ray Point, TX(b)
Green River, UT(c)
Gunnison, C0(d)
Falls City, TX(e)
Grants Mineral Belt, NM(f)
(Active Mills)
Contaminants
Barium, Lead, Vanadium
Arsenic
Arsenic, Chromium, Lead, Selenium
Arsenic, Barium, Chromium, Iron,
Lead, Selenium, Vanadium
Arsenic, Barium, Chromium, Iron,
Lead, Selenium, Radium, Vanadium
Polonium, Selenium, Radium,
Vanadium, Uranium, Ammonia,
Chloride, Nitrate, Sulfate
(a) (FB 76-78) (GJT-13)
(b) (FB 76-78) (GJT-20)
(c) (FB 76-78) (GJT-HO
(d) (FB 76-78) (GJT-12)
(e) (FB 76-78) (GJT-16)
(KA 75)
3-10
-------
(These figures exclude Grand Junction, where there is a separate remedial
action program.) Following the 1972 surveys, tailings from Cane Valley,
Arizona, and Edgemont, S. Dakota, have been used off-site, and in at least
one case—Salt Lake City—the gamma surveys were not completed. Table 3-5
shows the number of locations near each designated site where the use of
uranium mill tailings has been detected.
EPA began a complementary gamma radiation survey in the spring of 1974
to determine the extent of contamination by wind- and water-eroded
tailings at the inactive uranium mill sites (DO 75). Gamma radiation from
the ground was measured by adjusting detector readings for contributions
from other sources, including direct and scattered radiation from the
tailings pile. Gamma radiation from the ground at levels above the normal
background indicated contamination by tailings. Contour lines
corresponding to gamma radiation levels above background of 40 uR/hr,(D
lOuR/hr, and zero (i.e., background), were plotted on maps of each site to
show the locations of contamination (FB 76-78). Table 3-6 provides
estimates of the areas contaminated at a given gamma radiation level for
the 20 inactive sites surveyed. The Oregon Department of Human Resources
requested that the Lakeview site not be surveyed because the pile was
stabilized during the summer of 1974. The Canonsburg, Pennsylvania, site
also was not included.
roentgen (R) is a unit measuring the electrical charge gamma rays
release in air. A microroentgen (uR) is one millionth of a roentgen.
-------
TABLE 3-5
Gamma Radiation Anomalies and Causes^8)
Location
Arizona
Cane Valley(b)
Cameron
Cutter
Tuba City
State Total
Colorado
Cameo
Canon City
Clifton
Collbran
Craig
Debeque
Delta
Dove Creek
Durango
Fruita
Gateway
Glade Park
Grand Junction^)
Grand Valley
Gunnison
Leadville
Lotna
Mack
Mesa
Mesa Lakes
Molina
Naturita
Nucla
Palisade
Plateau City
Rifle
Salida
Slick Rock
Uravan
Whitewater
Idaho
Idaho City
Lowman
Salmon
State Total '
Number of
Anomalies
Detected
19
3
5
17
44
3
187
1083
145
86
109
43
83
354
1276
17
1
14542
110
47
91
199
90
123
3
43
33
13
939
28
810
64
9
209
55
0,795
3
12
77
52
Cause of Anomaly
Tailings
15
7
22
1
36
159
4
8
2
59
118
58
mfV
12
5178
10
3
•J
18
10
6
1
10
3
107
1
168
6
3
208
6191
-T75
Radioactive Source
or Ore
4
i
J. .
5
10 ~~* '
24
34
1 O
iy
67
/ A
48
(d)
39
*> T
2.1
4
7560^
_. 2
Natural
Radioactivity
3
3
99
14
46
1
29
2
67
26
-(d)
28
65
4
1
2
14
1
52
2
453^
2
3
65
Unknown
2
7
/
9
2
28
876
139
25
106
10
3
102
1144
3
2135
98
7
6
181
82
120
3
43
2
2
779
27
614
4
1
t. Q
49
6591
1
9
10
3-12
-------
TABLE 3-5 (Continued)
Gamma Radiation Anomalies and Causes(a)
Location
New Mexico
Bluewater
Gamer co
Grants
Milan
Shiorock
State Total
Oregon
Lake view
New Pine Creek
state Total
South Dakota
Edgemont
Edgemont
and Dudley(e)
Hot Springs
_ Provo
state Total
Texas
Campbell ton
Coughran
Falls City
Fashing
Floresville
George West
Karnes City
Kenedy
Panna Maria
Pawnee
Pleasanton
Poth
Three Rivers
Tilden
_ Whitsett
state Total
Number of
Anomalies
Detected
2
5
101
41
9
158
18
4
22
55
84
45
4
165
7
1
5
1
16
10
10
22
3
1
21
15
5
11
1
129
Cause of
Anomaly
Radioactive Source Natural
Tailings
1
7
5
8
21
43
17
3
63
2
2
1
1
6
or Ore
1
50
27
1
79
2
1
3
3
16
3
1
23
1
1
1
i
3
7
Radioactivity
5
25
1
31
10
10
1
51
17
69
6
1
3
14
10
6
13
3
17
14
2
11
1
101
19
8
27
6
3
9
8
25
33
2
2
7
1
1
2
15
3-13
-------
TABLE 3-5 (Continued)
Gamma Radiation Anomalies and Causes ^
Location
Utah
Bland ing
Bluff
Cisco
Crescent Junction
Green River
Magna
Mexican Hat
Mexican Hat
(Old Mill)
Moab
Monticello
Salt Lake City
Ly/j « C&UG VfllXcv \
SWltll tPl 1 TTIOO VM
— • **•*• ^ n uaxL^iiKo n<
Radioactivity
3
1
21
1
6
76
108
3
1
10
2
16
5
3
•J
53
33
94
955(d)
»s not included in
»s oeen m progress
Unknown
4
1
1
7
3
21
9
64
1
111
1
2
20
23
4T
6851
initial
since 1972
°ot
.
(e) Survey of additional anomalies conducted in 1978.
{fi Salt Lake City was not completely surveyed.
3-14
-------
TABLE 3-6
Contaminated Areas Around Inactive Uranium Mill Tailinea Piles
Colorado
Rifle (New),
Colorado
Rifle (Old),
Colorado
Slick Rock(NC),
Colorado
47
30
81
15
21
20
7
— — __
12 26
322 452
—
114 169
17 44
12
314
68
745
—
312
243
33
Slick Rock (UCC),
Colorado
Lowman,
Idaho
Ambrosia Lake,
New Mexico
Shiprock,
New Mexico
19
y(f)
104
118
3 41
11
210 390
126
81
16
617
229
3-15
-------
TABLE 3-6 (Continued)
Contaminated Areas Around Inactive Uranium Mill Tailings Pi
APPROXIMATE AREA (Excl. Pile) (Acres)
Site
Tailings
Pile
40 uR/hr above
Background
10-40 uR/hr above
Background
0-10 uR/hr
above Background
15.
Oregon
30
16. Canonsburg,'1*)
Pennsylvania 19
17. Falls City,
Texas 142
18. Ray Point,
Texas 48
19. Green River,
Utah 9
20. Mexican Hat,
Utah 77
21. Salt Lake City,
Utah 94
22. Converse County,
Wyoming 42
23. River ton,
Wyoming 72
139
19
114
256
39
44
127
198
88
99
411
94
153
457
510
187
460
(a) Reference DO 75
(b) Rock outcroppings and scattered ore made measurements difficult.
(c) Ponds covered with topsoil. Contaminated area could not be determined.
(d) Due to extensive development around site, contaminated area could not be determined.
(e) Contamination from plume extends several miles down valley
(f) Mill residue stockpile areas
(g) Gamma survey not done, at request of State.
(h) Gamma survey not done.
(i) Not included under UMTRCA
(j) — indicates data not available
(k) Includes tailings, overburden piles, and waste dumps. Tailings only constitute about 2.5
acres.
3-16
-------
References for Chapter 3
(AE 74) U.S. Atomic Energy Commission, 1974, "Phase I Studies of
Inactive Uranium Mill Sites and Tailings Piles" (summary and
individual site reports).
(BE 75) Bernhardt, D.E., Johns, F.B., and Kaufmann, R.F., 1975, "Radon
Exhalation from Uranium Mill Tailings Piles, Description and
Verification of the Measurement Method," U.S. Environmental
Protection Agency, Officer of Radiation Programs, Technical
Note ORP/LV-75-7(A).
(CU 73) Culot, M.V.S., Olson, H.G., Schiager, K.J., 1973, "Radon
Progeny Control in Buildings," Colorado State University.
(DO 75) Douglas, R.L. and Hans, J.M., Jr., August 1975, "Gamma
Radiation Surveys at Inactive Uranium Mill Sites," Technical
Note ORP/LV-75-5.
(DO 79) U.S. Department of Energy, January 1, 1979, "Statistical Data
of the Uranium Industry," DOE Grand Junction Office, Colorado,
GTO-100 (79). -
(DR 78) Dreesen, D.R., Marple, M.L., and Kelley, N.E., 1978,
"Contaminant Transport, Revegetation, and Trace Element
Studies at Inactive Uranium Mill Tailings Piles," in
Proceedings of the Symposium on Uranium Mill Tailings
Management, Colorado State University, Fort Collins, 111-139.
(FB 76-78) Ford, Bacon, and Davis, Utah, Inc., "Phase II-Title 1,
Engineering Assessment of Inactive Uranium Mill Tailings," 20
contract reports for Department of Energy Contract No.
E(05-l)-1658, 1976-1978.
(KA 75) Kaufmann, R.F., Eadie, G.G., and Russell, C.R., 1975, "Summary
of Ground Water Quality Impacts of Uranium Mining and Milling
in the Grants Mineral Belt, New Mexico," U.S. Environmental
Protection Agency, Office of Radiation Programs, Technical
Note ORP/LV-75-4.
(KL 78) Klute, A., and Heermann, D.F., September 1978, "Water
Movememnt in Uranium Mill Tailings Profiles," Environmental
Protection Agency, Office of Radiation Programs, Technical
Note ORP/LV-78-8.
(OR 73) Office of Radiation Programs, March 1973, "Summary Report of
the Radiation Surveys Performed in Selected Communities," U.S.
Environmental Protection Agency.
3-17
-------
References for Chapter 3 (continued)
(PU 77) Purtyman, W.D., Wienke, C.L., and Dreesen, D.R., "Geology and
Hydrology in the Vicinity of the Inactive Uranium Mill Tailings
Pile, Ambrosia Lake. New Mexico." T.A-fifl-*o_Me T »i
TK t6' NW Mexico'" LA-6839-MS, Los Alamos
Laboratory, New Mexico, 1977.
(SE 75) Sears, M.B., et al., 1975, "Correlation of Radioactive Waste
ine?hrSuC?pf V"? 'helEn*ir°nmental Impact of Waste Effluents
in the Nuclear Fuel Cycle for Use in Establishing 'as Low as
OakCRid:e Nat-UidrT\Millin8 °f Uranium °-s,"lwo Volume"
Oak Ridge National Laboratory report ORNL-TM-4903.
3-18
-------
4: HEALTH EFFECTS
4.1 Introduction
As metallic ore waste, uranium mill tailings are unique because of the
amount of radioactivity they contain. It is radioactivity that constitutes
their principal health hazard, though nonradioactive toxic chemicals such
as arsenic, lead, selenium, mercury, sulphates, and nitrates may also be
present. Milling uranium-bearing ore removes about 90* of the uranium.
The remainder, along with other radioactive material and toxic chemicals in
the processed ore, is discarded in the liquid waste and solid tailings.
Most of the uranium in uranium ore is uranium-238, a radioactive
isotope that decays over billions of years to become lead-206, a stable,
nonradioaotive element. The lengthy decay process passes through a series
of intermediate elements called decay products, such as thorium-230 and
radon-222; these, too, are radioactive. Fig. 4-1 traces the steps in the
decay series. Uranium decays since the ore was formed millions of years
ago have built up an inventory of the decay products identified in Fig.
4-1. In various concentrations, all are present in uranium mill tailings.
Uranium mill tailings emit three kinds of radiation: alpha rays, beta
rays, and gamma rays. All are forms of ionizing radiation, which breaks up
molecules into electrically charged fragments, or ions. In tissue,
ionization can produce harmful cellular changes. At the low radiation
levels naturally encountered in the environment we expect the effects of
such changes to be detectable only with difficulty. Studies show, however,
-------
FIGURE 4-1. URANIUM-238 DECAY SERIES
Uranium-238
4.5 billion
years
I
alpha
I
Thorium-234
24 days
Protactinium
234
1.2 minutes
s
f beta,
gamma
Uranium- 234
250,000
years
1?
beta,
^ gamma
I
alpha,
gamma
Thorium-230
80,000
years
t
alpha,
gamma
Radium-226
1,600 years
I
! alpha,
gamma
Radon-222
3.8 days
(alpha.
gamma
Polonium-
218
3 minutes
alp
ha
Lead-214
27 minutes
(ELEMENT)
(HALF-LIFE)
I
(PARTICLE OR
RAY EMITTED)
\
Ionium- Polonium-
214 210
1/6300 sec 138 days
| , jf. *
'gamma J*'3
Bismuth-214 D. .
19.7 minutes alpha, B.smuth-210
gamma 5davs alpha,
-j ,.J v
. X 1
beta, >"_ f
/gamma LearOm /beta,
r Lead-210 X gamma Lead- 206
22'3 V«rs ' $table
4-2
-------
that people exposed to high doses of radiation have a greater chance of
developing cancer. If the ovaries or testes are exposed, moreover, the
health or development of future children may be damaged.
No one can predict with precision the increased chance of cancer after
exposure to radiation. EPA and other Federal agencies base risk estimates
on studies of persons exposed at high doses, and assume that at lower doses
the effects will be proportionately less. Sometimes this assumption may
overestimate or underestimate the actual risk, but it is the best that can
be done at present (EP 76).
Alpha, beta, and gamma radiation all can cause harm. But the major
threat to health comes from breathing air containing radon decay products
with short half-lives(1)—polonium-218, for example—and exposing the
lungs and other internal organs to the alpha radiation these decay products
emit. In addition, radioactive material in the tailings pile may expose
people directly to gamma rays, or tailings particles may be breathed or
ingested. Except within a few miles of the pile, however, the potential
harm from breathing radon decay products is much greater.
The body's internal organs would still be exposed to alpha radiation
even if uranium tailings piles suddenly disappeared. Radium, uranium,
thorium, and other radioactive elements naturally present in ordinary rock
and soil emit alpha radiation; 1 picocurie of radium per gram of soil is a
(1)A half-life is the time it takes for a given quantity of a radioactive
isotope to decay to half of that quantity.
-------
typical concentration. Outdoor air contains a few tenths of a pCi of radon
per liter (UN 77). Normal eating and breathing introduces these and other
radioactive materials into the body, increasing the potential for cancer
and genetic changes. This discussion, therefore, compares the health risks
from tailings to those from normal exposure—not to justify the tailings
risk, but to provide a realistic context.
4.2 Radon and Its Immediate Decay Products
The most important decay product in the uranium-238 decay series, for
the purpose of defining the longevity of tailings' radioactivity, is
thorium-230, which decays to become radium-226. Because the half-life of
thorium-230 is 80,000 years, uranium tailings represent an essentially
permanent source of radium contamination. Radium in its usual chemical
form is relatively insoluble in water, so it can be controlled much as
other solid toxic materials with similar chemical characteristics. But
radon-222, the radium-226 decay product, is a nonreactive radioactive gas
that diffuses from the pile and becomes airborne. The half-life of radon
is 3.8 days, so some radon atoms can travel thousands of miles before they
decay.
As shown in Figure 4-1, the radon decay series leads through seven
principal members before ending with nonradioactive lead-206. The
potential health effects of breathing the short half-life radioactive decay
products immediately following radon are most important. Members of the
decay chain with relatively long half-lives (beginning with lead-210, with
a 22-year half-life) are more likely to be ingested than breathed and
represent less of a risk.
-------
The principal short half-life products of radon-222 are polonium-218,
lead-214, bismuth-214, and polonium-214—decaying, for the most part, in
less than an hour. Polonium-218, the first decay product, has a half-life
of just over three minutes. This is long enough for most of the
electrically charged polonium atoms to attach themselves to microscopic
dust particles, less than a millionth of a meter across, in the air. When
breathed, such small particles have a good chance of sticking to the moist
epithelium lining of the bronchial tubes in the lung. Most of the inhaled
material is eventually cleared from the bronchi by mucus, but not quickly
enough to keep the bronchial epithelium from being exposed to alpha rays
from polonium-218 and polonium-214. These highly ionizing rays pass
through several types of lung cells, but the doses they deliver to cells
that eventually become cancerous cannot adequately be determined. To do so
would require more detailed knowledge than we have of the deposition
pattern of the radioactive particles in the lung and the distances from
them to the cells. Further, there is even some disagreement about which of
the several types of bronchial cells the cancers originate in. Therefore,
we base estimates of lung cancer risk from inhaled radon decay products on
People's exposure to radon decay products rather than on the dose absorbed
in lung tissues.
Exposure to radon decay products is measured by a specialized unit
called the working level (WL). A WL is any combination of short half-life
Padon decay products which emits 130,000 million electron volts of
alpha-ray energy in one liter of air.
4-5
-------
The WL was developed to measure radiation exposure to workers in
uranium mines. The common unit of cumulative exposure is the working level
month (WLM), or occupational exposure to air containing one WL of radon
decay products for a working month, defined as 170 hours. Continuous
exposure of a member of the general population to one WL for one year can
be shown to be about 27 WLM (EP 78).
l|'3 E3timates of the Lung Cancer Risk from Inhaling Radon Decay Products
The very high incidence of lung cancer mortality among underground
miners is well documented (EP 78, AR 79). Uranium miners are particularly
affected, but lead, iron, and zinc miners exposed to relatively low levels
of radon decay products also show an increased lung cancer mortality that
correlates with exposure. The type of lung cancer most frequently observed
moreover, is rather uncommon in the general population.
Risk estimates for the general public based on these studies of miners
are far from precise. First and most important, the small number of miners
injects considerable statistical uncertainty (see Figure 4-2) into tne
number of "excess" lung cancer cases (that is, the number of cases beyond
those that would occur in any event). Second, the miners were exposed to
much higher levels of radon decay products than occur in the general
environment. Third, the exposure levels are uncertain. Fourth,
significant demographic differences between the miners and the public-the
miners were healthy males over 1. years old, many of whom smoked-imperil
an extension of the results of the studies to the general public.
4-6
-------
FIGURE 4-2
80
70
§
o
- 60
cc
iu
o
<
o
o
2
Ul
CD
o
o
I
50
30
20
10
All
JO
'3
O CZECH-URANIUM
O SWEDEN-LEAD, ZINC (A). IRON (R.J)
A UNITED STATES--URANIUM
• CANADA-URANIUM
I 95% CONFIDENCE LIMITS
RD
I
100 200 300 400 500
CUMULATIVE WORKING LEVEL MONTHS
600
700
Excess lung cancer in various miner groups as a function of their
cumulative exposure. Note the degree of statistical uncertainty in the
number of lung cancer attributable to radon daughters. After Archer
(AR 79).
4-7
-------
Information from the studies of miners can yield estimates, if not
predictions, of the risks from radon decay products to the general
population.CD Since the miners being studied have not all died,
however, their eventual excess lung cancers must be projected from current
data by using mathematical models.
There are two ways to use the observed frequency of lung cancer deaths
among the exposed miners in order to estimate the lifetime risk from
inhaling radon decay products: (1) relative risk, based on the percentage
increase in excess lung cancer deaths for each WLM, and (2) absolute risk,
based on the number of excess lung cancer deaths per WLM and the time, in
person-years, that the exposed population has been at risk at the time of
the study.
For relative risk, we conclude that a 3% increase in the number of
lung cancer deaths per WLM is consistent with data from the studies of the
underground miners. However, because there are important demographic
differences between adult male miners and the general population (EP 78),
the risk to the general population may be as low as 1% or as high as $%•
For absolute risk, we use the estimate of 10 lung cancer deaths per WLM for
one million person-years at risk reported by the National Academy of
Sciences (HA 76). Both of these "risk coefficients" are used in this
statement to examine the potential consequences of lifetime exposure to
radon decay products. Unless we state otherwise, we are estimating "excess"
(DSee "Indoor Radiation Exposure due to Radium-226 in Florida Phosphate
Lands" (EP 78) for such an analysis.
4-8
-------
cancer fatalities, i.e., those caused by elevated radiation levels and in
addition to those from other causes.
To estimate the number of lung cancer deaths from increased levels of
radon in the environment, we have used a "life table" analysis of the
additional risk due to radiation exposure (CO 78). This analysis takes
account of the length of time a person is exposed and the number of years a
person lives, based on the 1970 U.S. population death rate statistics, to
calculate the number of premature lung cancer deaths that would occur after
lifetime radiation exposure of 100,000 persons. As a basis for reference,
a life table analysis for the same population indicates a 2.9% chance of
lung cancer death from causes other than excess radiation. Using the
relative risk model, we estimate that a person exposed to 0.01 WL over a
lifetime incurs a 1.2* (1 in 80) additional chance of contracting a fatal
lung cancer. This estimate was made assuming children are no more
sensitive than adults. If childhood exposure results in three times
greater risk than that to adults, the estimated relative risk would
increase by about 50% (EP 78). Using a similar life table analysis and an
absolute risk model, we estimte that a person exposed to 0.01 WL over a
lifetime incurs a 0.6% (1 in 160) additional chance of contracting a fatal
lung cancer. Again, equal child and adult sensitivities are assumed (EP
78).
A person's average annual risk from a lifetime of exposure may be
obtained by dividing the lifetime risk estimates given above by an average
lifespan of 71 years. Regardless of the risk model used or assumptions
H-9
-------
concerning child sensitivity, our firmest estimate is that increased levels
of radon will produce an additional 1 to 3 lung cancer deaths per year of
exposure for each 100 person-working-levels of lifetime exposure.
Person-working-levels is the population's collective exposure; that is, the
number of people times the average concentration of radon decay products
(in working levels) to which they are exposed.
For the U.S. population as a whole, the number of cancers is larger
using a relative than an absolute risk estimate, but not for all regions.
The relative risk estimate for each inactive site is based on the lung
cancer death rate in that area. Lung cancer death rates are lower than the
national average in several of the States where inactive tailings sites are
located, so at some of the localities considered in Section 4.4 the
absolute risk is greater than the relative risk.
Radiation risk can be stated in terms of years of life lost due to
cancer deaths as well as in estimated numbers of cancer deaths. In the
relative risk model, the age at which lung cancer occurs is the same as in
the general population. Since lung cancer occurs most frequently in people
over 70 years of age, the years of life lost per fatal lung cancer—
14.5 years on average—is less than for many other fatal cancers. The
absolute risk model assumes that lung cancer fatalities occur throughout
life, so that each fatality reduces the lifespan by an average of 24.6
years. Therefore, even though the estimated number of lung cancer
fatalities using the relative risk model is nearly twice that using the
4-10
-------
absolute risk model, the total years of life lost in exposed populations is
nearly the same.
Because we used recent population data, our assessments illustrate the
current effects of tailings piles but do not predict future effects. If
the population sizes and locations, lifestyle, medical knowledge, and other
patterns of living affecting mortality remain unchanged, then these rates
of lung cancer death could persist for the indefinite future. We will not
attempt to assess future effects of tailings, which may either increase or
decrease. It is sufficiently prudent, we believe, to develop standards
which assume that estimated risk based on current data could persist over
the indefinite future.
For convenience, we will express results as deaths per 100 years.
This is simply the estimated annual rate based on current data multiplied
by 100.
4.4 Effects on Local and Regional Population from Radon Decay Products
The concentration of radon decay products changes rapidly with distance
from a pile, requiring complex models for determining the exposure to the
local population. An accurate estimate of the collective exposure from a
particular pile would include, besides the number of people exposed, the
site of each residence and work place and its ventilation characteristics;
the length of time a person is at each; and the wind speed and direction.
All of these factors determine the level of radon decay products inhaled by
an individual. Because these data are unavailable for the inactive sites,
4-11
-------
we relied upon more approximate methods to estimate regional exposure at
six of the 22 inactive sites (SW 80). We selected these six because enough
data to allow a quantitative analysis was available. Though limited, the
sample does include all but two of the urban sites. Our purpose in
performing the analysis was to illustrate the potential effects of tailings
in a variety of realistic regional circumstances.
We used U.S. census tract data to establish the number and locations
of exposed persons, based only on residence. (Census tract information is
rather precise, in urban areas, but less so in rural areas where the tracts
are large.) We assumed further that the wind pattern was symmetrical
around the pile, with a constant speed of 6.5 mph. The wind speed
determines the amount of dilution and, to a lesser extent,, the degree of
equilibrium between the emitted radon and its decay products(1). The
degree of equilibrium is important because the WL for a given concentration
of radon gradually increases as decay products accumulate. In this
analysis we assumed a radon-radon decay product equilibrium of 70% inside
all structures and in outside air more than 25 miles (Ho kilometers) from
the pile. We assumed 50* equilibrium in outside air within 25 miles. We
defined the local population as all persons living within about six miles
(10 kilometers) of the inactive pile, and the regional population as
*necaui?^^^^^ «
-r
»ost atmospheres are In an inte™dla?e rliatic^Mp '**
U-12
-------
persons living more than six but less than 50 miles (80 kilometers) from
the pile. We ignored population changes since 1970. A future increase in
population density at several of the urban sites seems likely, but because
the actual place of residence would be critical in determining exposure and
resulting health impact, we didn't try to incorporate projected population
growth.
Table 4-1 summarizes the results of our study of six piles at inactive
sites in terms of excess lung cancer deaths, average years of life lost per
cancer fatality, and the average number of days of life lost per exposed
person. The estimated number of lung cancer deaths associated with a
tailings pile is highly variable, depending not only on the size of the
pile but also the population density in its immediate vicinity. In contrast
to the estimates of national impact, described in Section 4.5, the estimated
number of fatal cancers for Utah residents based on the absolute risk model
is greater than that based on the relative risk model. This is because the
annual lung cancer death rates in Utah are comparatively low. The risks
listed in Table 4-1 are based on just radon emissions from the tailings
Pile, and include no additional risk from any use of tailings material in
construction.
At Canonsburg, Pennsylvania, most of the radon exposure is received by
persons working at the site. We estimate the risk to these workers and to
the local populations at Canonsburg as 29 or 17 fatal lung cancers per 100
years, using relative and absolute risk estimates respectively. From the
limited data currently available on the Canonsburg site, the risks there
4-13
-------
TABLE 4-1
Estimated Effect on Local and Regional Populations
From Exposure to Radon Decay Products from Tailings Piles
Salt Lake City. Utah
(Local Population — 361,000 persons)
Number of fatal cancers/100 yr
Years of life lost per fatality
Average days of life lost
per exposed person
Relative Risk
Estimates
72
15
0.8
Absolute Risk
Estimates
79
25
1.4
(Regional Population — 494,000 persons)
Number of fatal cancers/100 yr
Years of life lost per fatality
Average days of life lost
per exposed person
Relative Risk
Estimates
4
15
0.03
Absolute Risk
Estimates
5
25
0.06
Mexican Hat, Utah
(No Permanent Local Population — (1970 Census))
(Regional Population — 14,100 persons)
Number of fatal cancers/100 yr
Years of life lost per fatality
Average days of life lost
per exposed person
Relative Risk
Estimates
0.05
15
0.01
Absolute Risk
Estimates
0.05
25
0.02
4-14
-------
TABLE 4-1 (cont.)
Estimated Effeot on Local and Regional Populations
From Exposure to Radon Decay Products from Tailings Piles
Grand Junotion, Colorado
(Local Population — 39,800 persons)
Number of fatal cancers/100 yr
Years of life lost per fatality
Average days of life lost
per exposed person
Relative Risk
Estimates
29
15
2.6
Absolute Risk
Estimates
18
25
2.9
(Regional Population — 30,600 persons)
Number of fatal cancers/100 yr
Years of life lost per fatality
Average days of life lost
per exposed person
Relative Risk
Estimates
0.2
15
0.03
Absolute Risk
Estimates
0.2
25
0.03
Gunnison. Colorado
(Local Population — 5,060 persons)
Number of fatal cancers/100 yr
Years of life lost per fatality
Average days of life lost
per exposed person
Relative Risk
Estimates
3
15
2.3
Absolute Risk
Estimates
2
25
2.5
(Regional Population — 17,060 persons)
Number of fatal cancers/100 yr
Years of life lost per fatality
Average days of life lost
per exposed person
Relative Risk
Estimates
0.02
15
0.003
Absolute Risk
Estimates
0.01
25
0.004
4-15
-------
TABLE 1-1 (oont.)
Estimated Effect on Looal and Regional Populations
From Exposure to Radon Deoay Products from Tailings Piles
Rifle, Colorado (newer pile)
Number of fatal cancers/100 yr
Years of life lost per fatality
Average days of life lost
per exposed person
Number of fatal cancers/100 yr
Years of life lost per fatality
Average days of life lost
per exposed person
(Local Population ~ 2,700 persons)
Relative Risk
Estimates
1
15
1.5
Absolute Risk
Estimates
1
25
1.7
(Regional Population — 35,9QO persons)
Relative Risk
Estimates
0.03
15
0.003
Absolute Risk
Estimates
0.02
25
0.003
Shiprook. New Mexico
Number of fatal cancers/100 yr
Years of life lost per fatality
Average days of life lost
per exposed person
•within 10 miles
Number of fatal cancers/100 yr
Years of life lost per fatality
Average days of life lost
per exposed person
(Local Population* -- 7,200 persons)
Relative Risk
Estimates
15
1
Absolute Risk
Estimates
3
25
(Regional Population — 63,600 persons)
Relative Risk
Estimates
.1
15
0.007
Absolute Risk
Estimates _
.1
25
0.01
M-16
-------
seem comparable to those listed in Table 4-1 for the inactive piles located
in urban areas.
Table 4-1 shows the estimated collective risk to people in the
region. Within this group, the exposure and resultant risk to individuals
depends on their distance from the pile. Table 4-2 lists the calculated
exposure and estimated individual risks from lifetime exposure, as a func-
/
tion of distance from a hypothetical inactive pile with a radon emission
rate of 10,000 curies per year. The assumed wind speed and exposure condi-
tions are described above. Since the site is hypothetical rather than
actual, Table 4-2 lists only absolute-risk estimates. At actual sites, the
estimated absolute risks as a function of distance will be proportional to
the annual radon emission (listed in Table 3-D. For example, at a site
with emissions of 5,000 curies per year, the estimated risk to an individual
who lives a given distance away will be half of that listed in Table 4-2.
Table 4-2 highlights the significance of distance. At one to three
miles from the hypothetical pile, the increased radon concentration in
outside air roughly equals the normal concentration in residential
structures. Because distance is so important, it is useful to consider
specific sites.
In several urban areas, a few individuals live and work very near the
edge of tailings piles, where the concentration of radon is high.
Table 4-3 lists estimated working levels in outside air at homes close to
five of the urban sites. Except for the inactive pile in Salt Lake City,
4-17
-------
TABLE 4-2
Individual Risk From Lifetime Exposure
to Radon Decay Products from Tailings Piles
Radon
Distance from Pile Edge
(miles)
0.2
0.4
1.0
2.0
4.0
10.0
20.0
40.0
Release Rate — 10,000
Exposure
(WL)
0.013
0.005
0.001
0.0004
0.0001
0.00002
0.000004
0 . 000002
Ci per year
Chance
Lung
9200 in
3500 "
710 «
280 "
100 w
16 "
3 "
1 »
of Fatal
Cancer (a)
1 million
n n
it n
n n
ti n
it n
it n
n n
(a)Absolute risk model.
4-18
-------
TABLE 1-3
Estimated Risk to Nearest Residents from Inhaling
Radon Decay Products from Tailings Piles
(Lifetime Exposure at Current Levels)
Site Relative Risk Absolute Risk
Estimates Estimates
Salt Lake City, UT — (0.05 mile, 0.015 WL)(b)
Lifetime chance of fatal cancer 0.03 0.03
Years of life lost per fatality 15 25
Grand Junction, CO — (0.1 mile, 0.045 WL)(b)
Lifetime chance of fatal cancer 0.01 0.03
Years of life lost per fatality 15 25
Durango. CO — (0.1 mile, 0.026 WL)(b)
Lifetime chance of fatal cancer 0.03 0.02
Years of life lost per fatality 15 25
Rifle. CO — (0.5 mile, 0.007 WL)(b)
Lifetime chance of fatal cancer 0.008 0.005
Years of life lost per fatality 15 25
Gunnison. CO — (0.5 mile, 0.008 WL)(b)
Lifetime chance of fatal cancer 0.009 0.006
Years of life lost per fatality 15 25
(a) A risk of 0.03 is the same as 30,000 chances in 1 million, or 30 in
1 thousand.
The distance and radon concentration including background for the
nearest resident to the pile (FB 76-78).
. 1-19
-------
radon emissions from inactive piles are below the emission rate of 10,000
curies per year used to compile Table 4-2. The radon levels listed in
Table 4-3 are based on the site-specific Ford, Bacon and Davis Engineering
Assessments of inactive piles prepared for the Department of Energy
(FB 76-78), and are not directly comparable to the hypothetical cases in
Table 4-2. Estimates of individual risks for lifetime exposure at sites in
Table 4-3 are as high as a one-in-25 chance of death from lung cancer.
This is considerably greater than the risk from average residential radon,
about 1 in 300 (see below).
Table 4-4 estimates the risks from the naturally occurring radon decay
products found in ordinary homes near neither mill tailings nor any other
specifically identified radon source. National data on radon decay products
in homes is very scanty, and varies widely among individual houses. The
estimates in Table 4-4 assume that the average concentration is 0.004 WL in
homes occupied 15% of the time. The assumed average level of radon decay
products is based on recent data on 21 houses in New York and New Jersey
(GE 79), and is consistent with data obtained in other countries (UN 77).
For comparison, the risks estimated in Table 4-4 are about 10* of the
expected lifetime risk of lung cancer death from all causes (0.029) in a
stationary population having 1970 U.S. lung cancer mortality rates.
4*5 RlskS to the Continental U.S. Population from Radon Emitted from
Inactive Piles
Radon emissions from tailings piles may affect health beyond the 50
miles considered above. We estimated exposure to the U.S. population
4-20
-------
TABLE 4-4
Risk from Background Radon
in Residential Structures
.(a)
Lifetime chance of fatal lung cancer
Years of life lost per fatality
Average days of life lost
per exposed person
Estimated Risk
(b)
Relative
0.004
15
23
Absolute
0.002
25
18
(a)A risk of 0.004 is the same as 4000 chances in 1 million, or 4 in
1 thousand.
(b)calculated on the basis of 0.004 WL, home occupied 75% of the time,
and 1970 U.S. mortality rates (EP 78).
4-21
-------
beyond 50 miles using two different models for atmospheric transport. The
simplest, which treats radon diffusion on the basis of very general wind
patterns, yields an annual collective exposure of 0.65 person-working-level
for each 1000 curies of radon emitted per year to persons living more than
50 miles (80 kilometers) from an inactive pile (SW 80). A more detailed
meteorological model, developed for EPA by the National Oceanic and
Atmospheric Administration (NOAA), has been used by the Nuclear Regulatory
Commission (NR 79) to calculate the concentration in air of radon emitted
from four sites in the western U.S. A relationship between outdoor radon
concentration and working level is needed to compare the results of the two
methods. Assuming that a radon concentration of 100 pCi per liter corres-
ponds to about 0.7 WL (EP 78), the national collective exposure from the
four sites considered in the NRC study ranges from 0.42 to 0.76 person-
working-level per 1000 curies released per year, with an average of 0.56.
This agrees reasonably well with the results of the less detailed calcula-
tions, and is adopted here. This collective exposure does not include
people living within 50 miles of a pile.
Both the EPA and NOAA/HRC assessments assume a continental 0 s
population of 200 minion persona, based on ,970 U.S. oensus ^
geographically simUar population dlstrihutlon and a projected 1980
continental population of 220 million would increase the elective
exposure by about 10*.
A
M-22
-------
inactive tailings piles. The radon emissions on which the risk estimates
in Table U-5 are based are calculated from the size of the pile and the
amount of radium per gram of material, assuming a radon-222 emission rate
of 1 pCi/sec for each square meter of area and for each pCi of radiura-226
Per gram of tailings (SW 80). Complete field measurements are unavailable
and actual emissions could be considerably different from calculated values.
The total effect for persons living more than 50 miles from the 21
piles in Table 4-5 is summarized in Table M-6, which provides different
measures of health risk. They represent the total risk over 100 years for
an exposed population of 200 million; on average, an individual's annual
risk from the model pile is 20 billion times smaller.
U.6 Regional and National Effect from Long Half-Life Radioactive Materials
Windblown particles and the long half-life decay products of radon
(beginning with lead-210) are also potential hazards (see Figure 4-1). The
consequences of eating and breathing long half-life decay products cannot
be established without site-specific information—food sources, for
example. The only detailed study is one provided for a model active site
in the NRC Draft GEIS on Uranium Milling (NR 79). As explained below,
however, the NRC results apply in their entirety to few of the inactive
sites. We use the results of the NRC analysis here only to identify
important exposure routes and to compare their importance to that of the
short half-life decay products of radon. The results shouldn't be taken as
truly quantitative estimates of the risk at specific inactive sites.
The NRC model uranium mill and tailings pile is located in a sparsely
populated agricultural area based on cattle ranching. The population in
M-23
-------
TABLE 4-5
Approximate Contribution oj*Tailing Piles at Inactive Sites to the
National Health Risk from Radon Decay Products^
Inactive Site
Monument Valley, Arizona
Tuba City, Arizona
Durango, Colorado
Grand Junction, Colorado
Gunnison, Colorado
Maybell, Colorado
Naturita, Colorado
Rifle, Colorado(c)
Sliok Rock, Colorado(c)
Lowman, Idaho
Ambrosia Lake, New Mexico
Shiprock, New Mexico
Lakeview, Oregon
Palls City, Texas
Green River, Utah
Mexican Hat, Utah
Salt Lake City, Utah
Converse, Wyoming
Riverton, Wyoming
Annual Risk of Fatal Cancer
(deaths per year)
Relative Risk Absolute Risk
.006
.04
.02
.0?
.02
.04
.03
.06
.03
.005
.1
.04
.02
.1
.01
.065
.15
.003
.07
0.003
0.02
0.01
0.03
0.01
0.02
0.02
0.03
.01
.002
0.05
0.02
.01
.05
0.005
0.03
0.07
0.001
0.03
(a)Does not include effects within 50 miles of the site.
(b)Years of life lost and other measures of risk are discussed in
summary Table 4-6.
(c)Two inactive piles.
4-24
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TABLE U-6
Summary Table—Tailings piles at Inactive Sites
.(a)
Estimated National Risk of Fatal Lung Cancer from Radon Emissions
.(b)
Inactive Sites
Fatal cancers per 100 years
Increased chance of lung cancer death
Years of life lost per fatality
Average days of life lost
per exposed person
Estimated Risk
Relative
90
Absolute
0.3/1,000,000 0.1/1,000,000
15 25
0.0017
0.0013
(a) Canonsburg, PA, site not included.
Does not include people living within 50 miles of the site.
1-25
-------
this region produces all of its own food. Because this scenario maximizes
the dose due to food, it is inappropriate for many of the inactive sites.
For tailings near urban areas, with a large number of people living close
to the tailings pile, complete dependence on locally supplied food is
considerably less likely.
The five sources of exposure in the NRC analysis are shown in Table
4-7. The risk from breathing short half-life radon decay products is more
than 10 times greater than the next highest risk, that due to windblown
tailings eaten in vegetables and meat.d) Lead-210 and polonium-210,
formed in air following radon decay, are also a source of exposure when
deposited on food or breathed. According to the NRC analysis, the risk
from each of these pathways equals about one-hundredth of the risk from
breathing short half-life radon decay products. Even combined, the total
risk from the long half-life radionuolides is much less than the risk from
breathing the short half-life radon decay products. Persons living more
than 50 miles from an inactive pile would be less heavily exposed and their
risk would be considerably below that indicated in Table U-7.
4.7 Impact from Gamma-Ray Exposure
Many of the radioactive materials in tailings piles are a source of
gamma rays. Unlike alpha rays, which must originate within the body to
O)The NRC analysis for the ingestion pathway is quite conservative
because the retention on vegetation assumed for deposited materials (50*),
and the transfer of radium from fodder to meat (.003) are larger by a
factor of five or more than is usually assumed (EP 78a, MC 79),
4-26
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TABLE M-7
Regional Impact from Uranium Mill Tailings
(NRC-GEIS Model Pile and Population)
Population at Risk—57,300 persons
Number of Cancer
Deaths Per Year
Inhaled radon decay products
Ingestion of windblown tailings
Inhaled lead-210/polonium-210
Ingested lead-210/polonium-210
Inhaled resuspended tailings
.06(a)
.004(b)(c)
.0006(b)
.0006(b)
.00006(b)
the computed data for/individual radionuclides used to produce
—a_3ummarytables.in the'NRC-GEIS (NR 79). . „
<<0 Particles containing U-238, U-234, Th-234, Th-230, Ra-226, Pb-210,
Bi-210; c.f. Fig. 4.1
4-27
-------
become hazardous, gamma rays can penetrate both air and tissue for
considerable distances. Near the edge of a pile, the exposure from gamma
rays can be many times larger than the background level of gamma rays in
uncontaminated areas. The concentration of gamma radiation from the pile,
however, decreases rapidly with distance; at more than a few tenths of a
mile from moat of the inactive tailings piles, it is undetectable above
normal background.
Gamma ray exposures to individuals depend on how close to the edge of
a pile people live or work. The collective gamma ray dose depends on both
the number of people exposed and their average dose. In a few cases indi-
vidual doses can be approximated from available data, but generally this
cannot be done without a variety of information, such as where people live
and work and the amount of shielding provided by buildings. Outdoor gamma
ray exposures in the vicinity of some tailings piles at inactive sites are
summarized in Table 4-8. In several cases, even the nearest residents are
far enough from the pile that they receive essentially no excess gamma
radiation. At others, a few residents are located close enough to perhaps
double the dose from gamma radiation that would occur without the pile. In
a few cases, the dose to the nearest resident may be several times normal
background levels.
In most of these localities, "normal" background due to penetrating
radiation is about 100 mR per year (FB 76-78}.(1) This radiation exposes
(1)A milliroentgen (mR), or one one-thousandth of a Roentgen, is a unit
of radiation exnosnr*«.
of radiation exposure.
K-28
-------
TABLE 4-8
Increased Gamma Ray Dose Rates
From Tailings Piles at Inactive Sites
.(a)
Site
Durango, CO
Grand Junction, CO
Gunnison, CO
Rifle, CO
Lowman, ID
Ambrosia Lake, NM
Canonsburg, PA
Green River, UT
Salt Lake City, UT
Spook, WY
Location of Nearest Resident
Distance from Pile Edge
(miles)
Annual Gamma Ray
Exposure(b)
(mR/yr)
0.1
0.1
0.5
0.25
1.0
1.5
0.04
0.15
0.05
200-300
580
— (c)
-(c)
— (c)
-(c)
150
-(c)
465
1.5
-(c)
(a)Ambient gamma ray background at each site has been subtracted.
(b)Measured in air (Roentgens). At these energies continual exposure to
1 mR/yr gives an annual dose of 1 mrem.
(°)No detectable increase above background.
4-29
-------
the total body, so that all organs are at risk. The estimated frequency of
fatal cancer and serious genetic effects due to a lifetime exposure of 100
mR per year is listed in Tables 4-9 and 4-10. People who live or work near
tailings piles will incur higher risks from long-term exposures than those
listed in the tables in proportion to the excess of their annual dose rate
above 100 mR per year.
In summary, information does not allow calculation of the collective
gamma ray dose and risk to all persons living or working near the inactive
piles, but the total impact is small because the gamma-ray intensity falls
rapidly with distance from the pile.
4-8 Hazard from Water Contamination
4.8.1 Introduction
Evaluating the potential effects of nonradioactive toxic substances in
tailings requires different methods than those used for radioactive
substances. The basis for radiation risk estimates is that all ionizing
radiation can produce cancer, and that the probability increases with the
dose.d) With nonradioactive toxic materials, however, where the effect
varies with the material, and the severity of the effect-but not its
probability of occurring-increases with the dose, a classical analysis of
toxicity is used. Moreover, because the body can detoxify some materials
(DMany nonradioactive substances can induce ean^r* <«
animals (GO 77, VE 78). However for n««~^ ?! in exPerimental
uranium mill tailings, we dTnot' ° iVS substances found in
adequate for estimating risks for
4-30
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TABLE 4-9
Estimated Lifetime Risk of Fatal Cancer from
Total Body Gamma-ray Exposure at 100 mR/y
Estimated Risk(a)
Lifetime chance of fatal cancer
Years of life lost per fatality(b)
Average days of life lost
per exposed person
Relative
5 in 1000
14
24
Absolute
.8 in 1000
23
(a)Lifetime risk plateau.
(b)Based on a normal life span of 70.7 years,
4-31
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TABLE H-10
Estimated Risk of Serious Genetic Abnormalities
From Gonadal Dose of 100 mR per year
First All Succeeding
Generation Generations
Risk per 1000 live births O.OU to 0.6 0.1*1 to 5
Currently observed in U.S.A. 60 to 100
(per 1000 live births)
H-32
-------
or repair the effects of small doses, often no toxic effects occur below
threshold doses. With radiation, on the other hand, we assume there is no
dose below which effects do not occur.
Because of these differences, we cannot construct a numerical risk
assessment for nonradioactive toxic substances. We can, however,
qualitatively describe the risks of toxic substances in terms of their
likelihood of reaching people (or animals, or agricultural products);
concentrations at which they may be harmful; and their toxic effects.
4.8.2 Movement of Toxic Chemicals from Tailings
Tailings can contaminate both surface and ground water. Wind erosion,
floods, tailings slides into adjacent streams, seepage through the pile, or
runoff of rainwater all may cause surface water contamination. Ground
water contamination can occur only through seepage into an underlying
aquifer (a water-bearing layer of permeable rock). Since people may draw
water from a single underground source at many different places, exposure
to toxic chemicals greatly depends on the way the contaminants move. Since
their movement through lakes and streams is familiar, the following
discusses movement of dissolved contaminants in the ground.
Not enough information is available to estimate the chance that toxic
substances from tailings will move through water and expose people to
them. Migration of these substances in ground water near tailings piles,
however, has been observed. Chemical and hydrological principles can
4-33
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identify substances generally most likely to enter and be carried through
ground water, though the specific substances will vary among the sites.
Some organic compounds—amines, kerosene and higher alcohols, for
example—are present in tailings from acid leach mills. But the main
long-term ground water hazard is from leached inorganic toxic substances
and radioisotopes. Movement of contaminants to ground water depends on
complex chemical and physical properties of the underground environment,
and on such climate conditions as precipitation and evaporation. Chemical
and physical processes in the subsoil remove a portion of some contaminants
from water passing through it. Contaminants including selenium, arsenic,
and molybdenun, however, can occur in forms which are not removed.
Studies of leaching at tailings piles (DR 78) and leachates from
municipal land fills (EP ?8b) help determine which substances generally
will be relatively mobile or immobile, and which will have a mobility which
varies with local conditions (EP ?8c). Limited studies of pollutant
migration into ground water near tailings piles tend to confirm estimates
using other methods of elements that will be most mobile (FB 76-78, KA 76,
DA 77). There has been no systematic study, however, to establish the
magnitude of ground water contamination for tailings at either active or
inactive sites.
Based on available information, chromium, mercury, nickel, arsenic,
beryllium, cadmium, selenium, vanadium, zinc, and uranium have a high
probability of being mobile. Lead, radium, and polonium are not predicted
-------
to be mobile near tailings piles, but they appear to be mobile at some
locations. Data to suggest or confirm mobilities near tailings piles for
the other toxic elements are not available, but conservative assumptions
should be used for ions which are generally mobile, such as nitrate,
chloride, and sulfate. Certain anions (of arsenic, manganese, molybdenum,
and selenium, for example) and organic complexes of trace metals may also
be relatively mobile, although confirming field data from tailing pile
studies are extremely limited. If, however, seepage of substances known to
have high mobility is appreciably prevented or reduced, then it would seem
logical that those for which no data are available should also be
controlled.
When contaminated water from tailings reaches ground water, some
mixing generally will occur. Except in very coarse or cracked media,
through which contaminants flow relatively unimpeded, concentrations of
contaminants reaching ground water will likely be reduced along the flow
path by dispersion, and by absorption, adsorption, and ion exchange with
the ground material. The level of users' exposure to contaminated ground
water depends on the amount consumed as well as the level of contamination.
Consumption depends on the palatability and quality of the water, the
purposes for which it is used, and the number of users. Available data
indicate that tailings have contaminated some private wells in the Grant's
Mineral Belt in New Mexico (KA 76) with toxic substances whose concentra-
tions greatly exceed the National Interim Primary Drinking Water
Regulations that apply to public drinking water supplies (EP 76a).
4-35
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4.8.3 Tpxicity of Major Toxic Substances Found in Tailings
There is little data to estimate the probability or the level of
exposure to contaminated water, but reasonably good information exists on
its potential toxic effects. No acute effects—death in minutes or hours—
could occur except by drinking liquid direct from a tailings pond. Severe
sickness, or death within days to weeks, from the use of contaminated
ground water is possible, but unlikely.
Chronic toxicity, from the continuous consumption of contaminants at
rather low concentrations, could be a problem. Toxic substances can
accumulate slowly in tissues, causing symptoms only after some minimum
amount has accumulated. Symptoms of chronic toxicity develop slowly, over
months or years.
Tables 3-2 and 3-3 list many chemical elements and ions that have been
found in tailings piles. Many of these occur in tailings in only slightly
higher concentrations than in background soils and also have low toxicity
when taken orally (VE 78): lanthanides, including cerium, europium,
lanthanum, and terbium; silicates; and zirconium, scandium, boron, gallium,
and aluminum. Some other elements may be in elevated concentrations in
tailings, but they too are not very toxic: copper, manganese, magnesium,
cobalt, iron, vanadium, zinc, potassium, chloride, and sulfate. Some of
these elements an.d ions will also cause water to have an objectionable taste
and color we-MrlSelow concentration levels that are toxic to humans and
animals: iron, copper, manganese, chloride, and sulfate.
4-36
-------
Cyanide has a high oral toxicity in humans and animals, and has been
found in uranium mill tailings. Once it is released to the ground, however,
it is expected to be oxydized to the nitrate form, which is much less toxic
(NA 77).
Other substances are both present in tailings and are regulated under
the National Interim Primary Drinking Water Regulations (NIPDWR). Listing
in the NIPDWR is an indication of a significant need to limit direct human
consumption of these substances. The NIPDWR cover the inorganic chemicals
arsenic, barium, cadmium, chromium, lead, mercury, nitrate, selenium, and
silver. The toxicologies of these substances are discussed in Appendix C.
Fluoride is also covered by the NIPDWR, but has not been reported as present
in tailings. Molybdenum, though not included in the NIPDWR, is both toxic
and present in tailings in elevated concentrations; its toxicity is dis-
cussed in Appendix C. Tailings also contain elevated levels of naturally
radioactive substances, such as radium, thorium, uranium, and their decay
products. Appendix C discusses both the chemical and radiological toxic
effects of ingesting radium, thorium, and uranium.
Tailings are not significant sources of other toxic materials that are
regulated in the NIPDWR, such as organic substances, microbiological organ-
isms, and man-made radioactivity.
4.9 Conclusions
At many of the inactive mill sites, health risk to individuals is
increased because of inhaled radon decay products (c.f. Tables 4-3 and 4-4)
4-37
-------
and gamma ray exposures from tailings. Table 4-11 summarizes the local,
regional, and national risks due to radon decay products from the inactive
sites. In preparing Table 4-11, we have supplemented the data presented
elsewhere in this chapter with other analyses of population exposure from
tailings piles (FB 76-78) so as to include all sites. All of these
estimates are based on current populations and therefore will change with
population growth as well as living patterns. At present, most of the
potential effect is projected to occur in the regions near the inactive
tailings pile. The national effect, however, is comparable.
Compared to the risk from short half-life radon decay products (see
Table 4-11), the other radiological risks are much less significant. At
most, they increase by 10% the risk estimated for the regional population,
and the risk to the national population is much less. This incremental
risk is small compared to the uncertainty—at least a factor of two—in the
estimated risk for lung cancer death from the short half-life radon decay
products.
The nonradioactive toxic substances present in an inactive tailings
pile and their potential impact on public health and the environment must
be determined for each site. Those substances which can move through
ground water and which have the greatest potential toxicity include arsenic,
barium, cadmium, silver, chromium, lead, mercury, molybdenum, selenium,
nitrate, iron, and vanadium. In addition, among radioactive substances,
uranium is most likely to be mobile in ground water, and radium and
polonium are possibly mobile.
4-38
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TABLE 4-11
Summary— Risks from-Radon Emitted from Tailings Piles at Inactive Sites
(Short Half-Life Radon Decay Products)
Estimated-Fatal Cancers (per 100 years)
Relative Risk Absolute Rxsk
Model Model
Deaths occurring within
50 miles of site 150 130
Deaths occurring more than
50 miles from site J2£ -12
TOTAL 240 170
4-39
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References for-Chapter 4
(AR 79) Archer, V.E., "Factors in Exposure Response Relationships of Radon
Daughter Injury," Proceedings of the Mine Safety and Health
Administration, Workshop on lung Cancer Epidemiology and
Industrial Applications of Sputum Cytology, November 14-16, 1978,
Colorado School of Mines Press, Golden, Colorado (1979).
(CO 78) Cook, J.C., Bunger, B.M., Barrick, M.K., "A Computer Code for
Cohort Analysis of Increased Risks of Death," CSD/ORP Technical
Report No. 520/4-78-012, USEPA, Washington, D.C. (1978).
(DA 77) D'Appolonia Consulting Engineers, Report 3» Environmental Effect^
of Present and Proposed Tailings Disposal Practices, SplitRoctc
Mill, Jeffery City, Wyoming, Volumes I and II. Project No. SM
77-419 (1977).
(DR 78) Dreesen, D.R., Marple, M.L., and Kelley, N.E., Contaminant
Transport, Revegetation, and Trace Element Studies at Inactive
Uranium Mill Tailings Piles, pp. 111-139 in Proceedings of the
Symposium on Uranium Mill Tailings Management, Colorado State
University, Fort Collins, Colorado (1978).
(EP 76) EPA Policy Statement on the Relationship Between Radiation Dose
and Effect, 41 F.R. 28409, July 9, 1976.
(EP 76a) Environmental Protection Agency. National Interim Primary
Drinking Water Regulations, EPA-570/9-76-003. USEPA, Office of
Water Supply, Washington, D.C. (1976).
(EP 78) "Indoor Radiation Exposure Due to Radium-226 in Florida Phosphate
Lands." EPA 520/4-78-013, U.S. EPA, Washington, D.C. (July 1979).
(EP 78a) "Response to Comments; Guidance on Dose Limits for Persons Exposed
to Transuranium Elements in the General Environment," EPA
520/4-78-010, U.S. EPA, Washington, D.C. (1978).
(EP 78b) Investigation of Landfill Leachate Pollutant Attenuation by Soils»
EPA-600/2-78-158.USEPA, Municipal Environmental Research
Laboratory, Cincinnati, Ohio (1978).
(EP 78c) Attenuation of Pollutants-in Municipal Landfill•Leachate by Clay
Hinerals, ^PA-600/2-78-157, tfSEPA, Municipal Environmental
Research Laboratory, Cincinnati, Ohio (1978).
(FB 76-78) Ford, Bacon and Davis Utah, Inc., Phase II-Title I
Engineering Assessment of Inactive Uranium Mill Tailings, DOE
Contract •:No.~E(05-l)-165li, Department of Energy, Washington,
D.C. (1976-78).
4-40
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(GE 78) George, A.C. and Breslin, A.J., "Distribution of Ambient Radon and
Radon Daughters in New York and New Jersey Residences,"
Proceedings of Natural Radiation-Environment III, April 23-28,
1978 tto be published!, University of Texas, Houston, Texas.
(GO 77) Goyer, R.A. and Mehlman, M.A. editors, Toxicology of-Trace
Elements, Advances in Modern Toxicology, Vol. 2. John Wiley &
Sons, New York (1977).
(KA 76) Kaufman, R.F., Eadie, G.G., and Russell, C.R., "Effects of Uranium
Mining and Milling on Ground Water in the Grants Mineral Belt, New
Mexico," Ground Water 14;296-308 (1976).
/
(NA 77) National Academy of Sciences, Drinking Water and Healthy Part 1»
Chapters 1-5, NAS Advisory Center on Toxicology, Assembly of Life
Sciences, Washington, D.C. (1977).
(NR 79) Draft Generic Environmental Impact Statement on Uranium Milling,
Volume II, NUREG-0511, U.S. Nuclear Regulatory Commission,
Washington, D.C. (1979).
(SW 80) Swift, J.J. "Distant Health Risks from Uranium Mill Tailings
Radon," U.S. EPA, Office of Radiation Programs, Technical Note
ORP/TAD-80-1, 1980 (to be published).
(UN 77) "Sources and Effects of Ionizing Radiation," United-Nations
Scientific Committee on the Effects of Atomic Radiation, 1977,
Report to the General Assembly, U.N. Publication E.77.IX.1,
United Nations, NY.
(VE 78) Venugopal, B. and Luckey, T.D., Metal Toxici ty_ in Mammals .2>
Chemical Toxicity of Metals and Metaloids, Plenum Press, New York
(1978).
4-41
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5: ALTERNATIVE TAILINGS DISPOSAL CONTROL LEVELS
5.1 Introduction
Generally applicable standards to protect the public health and safety
and the environment must consider reasonable and feasible methods of
controlling uranium mill tailings. The longevity of control methods is
important, because radioactive contaminants have long lifetimes and
nonradioactive contaminants are permanently toxic.
The predominant health hazard of tailings is from radon-222 released
into the atmosphere. Techniques providing reasonable long-term control of
radon also provide nearly complete control of particulate releases and
direct gamma radiation. This chapter discusses control of radon-222 and
the water pathway, and longevity of control.
The degree of radon control that we could require ranges from none
(leaving the sites as they are) to nearly total (little or no radon release
from tailings). The following compares three degrees of control for their
costs, benefits, feasibility, longevity, and other considerations in
developing an appropriate standard;
a. No control (the existing situation).
b. Radon releases controlled at various levels down to about the
natural background rate.
c. Complete control (practically no release).
-------
For potential water contamination, control alternatives similarly
range from none to total. The control levels examined are:
a. No control (the existing situation).
b. Control comparable to other water quality programs.
c. Complete control (no contamination).
Ultimately, health protection will depend on the time over which
controls are maintained as well as the degree. We examined the technical
and economic reasonability of requiring effective control for the following
periods:
a. Several hundred years.
b. Hundreds to thousands of years.
c. Longer than tens of thousands of years.
5.2 Control of Radon-222 Releases
Radon release control methods range from a simple barrier between the
tailings and the atmosphere to such ambitious treatments as embedding
tailings in cement or processing them to remove the radon sources.
Barriers should be able to resist wind and water erosion and human
intrusion. Radon control techniques and estimates for various levels of
control are discussed more fully in Appendix B. A general discussion of
radon control and the ancillary benefits of controlling other potential
hazard pathways follows.
5-2
-------
5.2.1 Radon Control
Radon-222 releases into the atmosphere can be controlled by covering
the tailings with an impermeable barrier, like plastic, or by enough
permeable material, like soil, to slow down the radon passing through so
that the amount of radon released is reduced because of radioactive decay.
Generally, the more permeable the covering material, the thicker it must be
for a given reduction in radon release. Maintaining the integrity of thin
impermeable covers over periods even as short as tens to hundreds of years,
however, is highly uncertain under the likely range of chemical and
physical stresses.
Natural materials can be used, such as soil, clay, gravel, or a
combination. Clay-type material, especially when moist, generally resists
the passage of radon much more than an equal thickness of soil or sand.
The half-value-layer (HVL) is that thickness of cover material which
reduces the radon release to one-half its uncovered value. Table 5-1 shows
the approximate HVL of typical natural materials for reducing radon
releases. These HVL values are nominal; HVLs at actual sites depend on
soil composition, compaction, moisture present, and other factors.
Figure 5-1 shows nominal curves for the percentage of radon which
would penetrate various thicknesses of different materials (FB 76-78).
Using the HVL concept, about seven HVLs of cover reduces radon releases to
less than 1% of the uncovered rate, and about 10 HVLs reduce the release to
less than 0.1%. Radon reductions are multiplicative for HVLs of the same
5-3
-------
TABLE 5-1
Nominal Half-Value-Layers of Typical Natural
Materials for Reducing Radon
Material
Sandy, porous soil
Mid-range, typical Western soil
Well compacted, moist soil
Moist clay
HVL
1.0 meters
0.5 meters
0.3 meters
0.12 meters
(a)
From (MR 79) Appendix K, Chapter 9 and 12.
5-4
-------
FIGURE 5-1
100
A=SANDY SOIL (HVL = 1.0 M)
B = SOIL (HVL = 0.5 M)
C = COMPACTED, MOIST SOIL
(HVL=0.3 M)
D=CLAY(HVL=0.12 M)
2345
COVER THICKNESS (METERS)
6
5-5
-------
or different materials. For example, one HVL of soil plus one HVL of clay
reduce radon releases to 25% of the uncovered value (50% x 50% • 25%).
Uranium mills are generally located near the mines where the ore is
obtained, and often other mines are nearby. Disposing tailings in these
mines should be seriously considered. The thick cover and erosion protec-
tion would almost completely control radon emission for substantially
longer than could generally be expected using above-grade disposal methods.
Since mines are usually below the water table, however, elaborate and costly
ground water protection methods might be needed, and it is not clear that
effective methods are known. There will be transportation hazards and
coats. Even where otherwise suitable mines are near an inactive processing
site, using them for tailings disposal might make future development of the
mine's residual resources impossible.
5.2.2 Effects of Radon Control on Release of Airborne Particulates
Methods that control radon will also control releases of airborne
particulates. Either a thin impermeable cover or a thicker natural
material cover will prevent particulates from becoming windborne. Any
covering will prevent the spread of windblown tailings as long as the
integrity of that cover is maintained. Therefore, assuming that some
control of radon release will be required, control of airborne particulates
needs no further discussion.
5-6
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5.2.3 Effects of Radon Control on Direct Gamma Radiation
Covering tailings piles to reduce radon-222 releases will also reduce
direct radiation. As with radon, attenuation of gamma radiation depends on
the thickness of the cover. Figure 5-2 shows the nominal percentage of
gamma radiation that will pass through a given thickness of compacted soil.
The HVL of compacted soil is about 0.1 meters. Soil compaction, moisture
content, type of soil, and other parameters all are factors. A thin,
impermeable cover, such as a plastic sheet, will reduce gamma radiation
insignificantly. A thicker cover of a material such as soil will provide
significant reduction. Comparing the HVLs of soil for reduction of radon
releases and reduction of gamma radiation, coverings of soil-like material
thick enough to significantly reduce radon emissions will greatly reduce
gamma radiation. Again, assuming that some radon control will be required,
direct gamma radiation exposure from tailings piles will be addressed no
further.
5.2.4 Effects of Radon Control on Potential Water Contamination
Covering uranium mill tailings piles to reduce radon-222 releases can
also help to control potential contamination of surface and ground water.
A cover will prevent the wind from blowing tailings directly or indirectly
into surface water, and may control erosion caused by precipitation, runoff,
or streams. The proper cover can reduce infiltration of precipitation into
the piles. A thin, impermeable cover would prevent all infiltration, so
long as the cover remained intact. A thicker cover of natural materials,
especially if clay-like and shaped as a dome, might provide an infiltration
barrier and encourage run-off.
5-7
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100
FIGURE 5-2
COMPACTED SOIL
(HVL = 0.1 M)
0-2 0.3 0.4 0.5
COVER THICKNESS {METERS)
0.6
0.7
5-8
-------
Covering tailings below ground in specially-dug pits, open pit mines,
or underground mines—can greatly help to control surface water contamin-
ation by reducing erosion. Care must be taken, however, not to contaminate
useable ground water with radioactive and nonradioactive pollutants.
5.3 Control of Surface and Ground Water Contamination
A suitable cover can prevent surface water from being contaminated by
windblown tailings. Control of erosion caused by streams or precipitation
could consist of contouring and covering the pile and stabilizing the
surface—that is, making it resistant to erosion. If necessary, the pile
could be moved to a site away from existing streams and then covered. A
suitable cover can reduce leaching of contaminants caused by precipitation
that soaks into the pile.
Ground water contamination, caused by direct contact with the tailings
and leaching of the radioactive and nonradioactive contaminants, may be the
most difficult problem. There are two general approaches to limiting
direct contact with groundwater. First, the tailings can be placed far
enough above the water table and its predicted fluctuations to avoid
contact. Second, an impermeable barrier would be imposed between the
tailings and the ground water. In some cases, to make these control
approaches feasible and long-lasting, the pile must be moved. Some of the
existing tailings sites may already be in a suitable position above the
water table. At other sites, however, continuous contact with ground
water, or periodic contact as the water table fluctuates, occurs.
5-9
-------
Ground water contaminant concentrations near the inactive mills were
surveyed as part of the Phase II studies (FB 76-78), and case histories of
some water contamination problems near uranium mills and mines are given in
a report prepared for EPA (GE 78). There is evidence that ground water
near some inactive sites is already contaminated, probably due to seepage
of liquids from tailings ponds during and after their active use. Such
seepage may now have slowed, because the tailings ponds at inactive sites
have partially dried up. However, leaching by precipitation that infil-
trates uncovered tailings piles is still a possibility.
Recent studies by Markos (MA 79) of tailings at inactive 'sites suggest
that soluble contaminants sometimes move to the surface of the piles rather
than to the ground. If confirmed, these studies would suggest that ground
water contamination by long-term leaching is less likely than it might seem.
The processes that carry substances upward through the piles, however, might
also cause them to penetrate cover materials. If this should happen, these
substances would then be carried off the site by wind and precipitation.
Although the potential effects of such processes have not been assessed,
contamination of surface water appears to be possible. Disposal system
designers will have to consider the potential effects of such contaminant
transport processes in choosing suitable disposal concepts, materials, and
sites. At present, it is unclear what methods, if any, may be needed
specifically to avoid harm to the environment and public health from
upwardly mobile soluble contaminants.
5-10
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Proper disposal of tailings piles should prevent or reduce
contamination from new releases. However, water supplies could become
contaminated in the near or distant future by toxic materials that are
already on their way to an aquifer. These substances may move slowly
through the ground. Ground water itself can move slower than a few feet pei
year, and only in coarse or cracked materials does the speed exceed one mile
per year. For these reasons, pollutants released from tailings may not
affect the quality of nearby water .supplies for decades or longer. However,
once polluted, the quality of such water supplies cannot be quickly restored
by eliminating the source of pollutants. Even if a pile is disposed of so
there is no further seepage, it may take nature longer to restore the
original water quality throughout the affected area than the time from the
start of the pile to the first contamination of water supplies.
Toxic substances released from a pile but not yet in contact with an
aquifer could be very difficult to trace and remove. A recent report pre-
pared for EPA (JR 80) reviews methods that sometimes can improve the quality
of an already contaminated aquifer. The economic and technical practicality
of achieving any preset degree of cleanup is uncertain, however, especially
for general application at all sites. The only feasible generally applic-
able control would be to monitor the quality of the aquifer and limit the
use of its water. How long this may be necessary depends on the degree of
contamination, the rate of ground water movement, the amount of dilution
and dispersion taking place, and the intended use of the water.
5-11
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5.4 Longevity of Control
The longevity or permanence of any control methods used is of prime
concern. Because of the long lifetimes of the radioactive contaminants
(thorium-230 has a half-life of about 80,000 years) and the presence of
other toxic chemicals (which never decay), the potential for harming people
and the environment will persist indefinitely. The ultimate objective of a
disposal program is not only to reduce the potential hazards to an accep-
table level now, but also to control these potential hazards for as long as
their source persists.
This section examines the pertinent technical and social factors that
influence the choice of periods for applying pollution control standards
for tailings disposal.
5.4.1 Effects of Natural Forces
Natural forces may disrupt attempts to isolate radioactive waste, as
several authors have discussed (EP 78, GS 78, LU 78, NE 78, GS 80). The
factors affecting long-term performance are numerous and interrelated, and
include some over which people may have no influence. Our general belief
is that stability against natural forces could reasonably be expected for a
few hundred to a few thousand years by dealing with the problem on a c*se-
by-case basis and taking site-specific factors into account. Predictions
of stability become less certain as the time period increases. Beyond
several thousand years, long-term geological processes and climatic change
will determine the effectiveness of most "permanent" control methods.
Glaciation, volcanism, uplifting and denuding of the Earth's surface, and
5-12
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deposition of material have occurred during the past 100,000 years and will
continue.
In a report for Argonne National Laboratories, "Evaluation of Long-Term
Stability of. Uranium Mill Tailing Disposal Alternatives" (KE 78), Nelson and
Shepherd considered the impact of natural phenomena, including earthquakes,
floods, windstorms, tornadoes, and glaciers. These events could disperse
the tailings, making possible chronic exposure to their radioactive and
nonradioactive toxic constituents. The following comments are summarized
from their report.
5.4.1.1 Earthquakes
Earthquakes can damage caps and covers, as well as disrupt barriers
under disposal sites. The number and magnitude of past earthquakes in an
area suggest the probability of earthquakes in the future. As with any
natural phenomenon, the confidence in such predictions rises as the time
period for which reliable earthquake and faulting information is available
increases. The likelihood that controls will fail because of an earthquake
depends on the chance of an earthquake greater than that in the design
model. Even if a disposal plan is designed on the basis of the maximum
credible earthquake, there is always the chance of a larger one. If an
earthquake occurs at a site, the likelihood that controls will fail will
generally be high. The quantity of tailings released, however, may be
small.
5-13
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5.4.1.2 Floods
Flooding can result from large rainstorms, rapidly melting snow, or
local cloudbursts. The. erosion floods cause can impair tailings control.
Increased soil moisture from flooding may also make slopes unstable and
lead to landslides. Flooding frequency and the "maximum probable flood"
are predictable from historical stream flow data and hydro-meteorological
data. Over extremely long time periods, however, even the maximum probable
flood can be exceeded. With changes in climate, the frequency of floods
and the maximum probable flood may change. Floods are not time-dependent;
two large floods can occur in successive years, though the probability is
slight. The effects of floods can be cumulative if maintenance or
corrective action is not employed.
5.4.1.3 Windstorms and Tornadoes
The frequency and intensity of windstorms and tornadoes are histor-
ically predictable. Such predictions, however, suffer from the same
uncertainties as earthquake and flood predictions. The primary impact on
tailings piles would be wind erosion of the cover or of the material itself.
With a suitable cover or cap on the tailings, and protection of the surface
against wind erosion, winds and tornadoes should have little effect.
5.4.1.4 Glaciation
Glaciers occur in mountain valleys and as ice sheets, such as in
Greenland. Because of the magnitude of the forces associated with glaci-
ation, no portion of a surface depository would be likely to survive even a
small, relatively short-term glacier. The likelihood of continental
5-14
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glaciation in the Western U.S., even far into the future, is remote. No
evidence exists of continental glaciation south or west of the Missouri
River. Increased valley glaciation in the west is a possibility, however.
Several glaciers exist high 5n the Rocky Mountains, and heavy glacial
activity existed in the mountains as recently as 10,000 years ago. Increase
in valley glaciation is likely over the long term. Previously glaciated
mountain valleys are less desirable as disposal sites than nonglaciated
sites, such as flat terrain or valleys created entirely be erosion. The
possibility of valley glaciation should he considered in choosing surface
or below-ground disposal methods.
5*^*2 Effects oj^Huma n_Ac tivity
Disruption of tailings isolation by people is also a possibility. The
NRC has discussed the problem (in Chapter 9 of the DCEIS), especially the
need for land use controls. Building atop a disposal site, excavating or
drilling, or using the surface land for grazing and tilling could disrupt
controls or accelerate natural erosion processes. Tt has been suggested
that a disposal site should not be made more attractive to human or animal
habitation than the surrounding environs, and perhaps it should be less
attractive to discourage potential future occupancy (SH 78).
PL 95-604 requires that final disposal, sites for residual radioactive
material be owned by an agency of the Federal Government and licensed by the
NRC (42 USC 7901). Such Federal responsibility should provide control of
any human activity which might disrupt isolation of the tailings for as long
5-15
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as that responsibility is exercised. From a historical perspective,
however, we should not expect institutions to perform such functions for
more than a few centuries (RO 77, SC 77, EP 78a, BI 78, LU78). In its
proposed criteria for management of radioactive wastes (FR 78), EPA stated
that one should not plan to rely on institutional controls for more than
100 years. During the period of effective institutional control, it
should be possible to detect and remedy the minor effect of natural force,s,
such as wind or water erosion. This should provide some assurance of
continued stability against natural forces for a longer period of time.
Selecting disposal sites to isolate tailings from expected habitation and
land-use patterns, at remote location or deep underground locations, or
both, is one way to protect against degradation and intrusion by human
activity after institutional control has become ineffective.
5-16
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References for Chapter 5
(BI 78) Bishop, W.P., et al., May 1978, "Proposed Goals for Radioactive
Waste Management,TrU.S. Nuclear Regulatory Commission,
NUREG-0300.
(EP 78) U.S. Environmental Protection Agency, June 1978, "State of
Geological Knowledge Regarding Potential Transport of High-^
Level Radioactive Waste From Deep Continental Repositories,"
Report EPA 520/4-78-004.
(EP 78a) U.S. Environmental Protection Agency, February 1978,
"Considerations of Environmental Protection Criteria for
Radioactive Waste."
(FB 76-78) Ford, Bacon, and Davis, Utah, Inc., "Phase II-Title 1,
Engineering Assessment of Inactive Uranium Mill Tailings,
20 Contract reports for Department of Energy Contract
No. E(05-l)-1658, 1976-1978.
(FR 78) Federal Register, 43 F.R. 53262-53267, November 15, 1978.
(GE 78) Geraghty and Miller, Inc., "Surface Impoundments and Their
Effects on Ground-Water Quality in the United States — A
Preliminary Survey," report prepared for the U.S. Environ-
mental Protection Agency, EPA 570/9-78-004, June 1978.
(GS 78) U.S. Geological Survey, 1978, "Geologic Disposal of High-Level
Radioactive Wastes — Earth-Science Perspectives," Circular 779.
(GS 80) U.S. Geological Survey, 1980, "Isolation of Uranium Mill
TAilings and their Component Radionuclides from the Biosphere,
by Edward Landa, Circular 814.
(JR 80) JRB Associates, Inc., "Manual for Remedial Actions at Waste
Disposal Sites," draft final report under EPA Contract
No. 68-01-4839, submitted June 1980.
(LU 78) Lush et al., 1978, "An Assessment of the Long-Term Interaction
of UraniunTTailings with the Natural Environment," from
Proceedings of the Seminars on Management, Stabilization and
Environmental Impact of Uranium Mill Tailings, The OECD Nuclear
Energy Agency, pp. 373-398.
(MA 79) Markos, G., 1979, "Geochemical Mobility and Transfer of
Contaminants in Uranium Mill Tailings," from Proceedings of the
Second Symposium on Uranium Mill Tailings Management, Colorado
State Univ., Nov. 1979.
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(NE 78) Nelson, J.D., Shepherd, T.A., April 1978, "Evaluation of
Long-Term Stability of Uranium Tailing Disposal Alternatives,"
Civil Engineering Department, Colorado State University,
prepared for Argonne National Laboratory.
(NR 79) U.S. Nuclear Regulatory Commission, April 1979, "Generic
Environmental Impact Statement on Uranium Milling," NUREG-0511-
(RO 77) Rochlin, G.I., "Long-term Waste Management: Criteria or
Standards?" in Proceedings of a Workshop on Issues Pertinent to
the Development of Environmental Protection Criteria for
Radioactive Wastes, EPA Report ORP/CSD-77-1 (1977).
(SC 74) Schiager, K.J., July 1974, "Analysis of Radiation Exposures on
or Near Uranium Mill Tailings Piles," in Radiation Data and
Reports, pp. 411-425. ~~
(SC 77) Schiager, K.J., "Radwaste Radium-Radon Risk," in Proceedings
of a Workshop on Policy and Technical Issues Pertinent to the
Development of Environmental Protection Criteria for
Radioactive Wastes, EPA Report ORP/CSD-77-2 (1977).
(SH 78) Shreve, J.D., Jr., July 1978, in Proceedings of the Seminar on
Management, Stabilization and Environmental Impact of Uranium
Mill Tailings, the OECD Nuclear Energy Agency, p. 350.
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6: MONETARY COSTS AND THE EFFECTS OF TAILINGS DISPOSAL
This chapter presents the range of monetary costs for alternative
pollutant control levels, and addresses the longevity characteristics of
disposal methods, the potential environmental impact of controls,
occupational hazards, and effects of the disposal program on the economy.
6.1 Estimated Costs
Cost estimates assume an inactive tailings pile whose area, volume,
and weight approximate the average values for piles at 21 inactive sites.
This "average" pile has a surface area of a little more than 19 hectares
(190,000 square meters, or 47 acres), contains 780,000 cubic meters (1
million cubic yards) of tailings, and weighs 1.3 million short.tons. The
pile is shaped like a truncated pyramid with a base approximately 440
meters (1440 feet) on a side, including the embankments. The radon-222
release rate is assumed to be 450 pCi/m2-sec, (More detail on the
"average" pile is given in Appendix B.) Cost estimates for a tailings pile
of different size can be scaled from the "average" pile by using the unit
costs developed for individual tasks and the purchase of specific items, as
presented in Appendix B. (These items include earth work, liners and caps,
stabilizers, fencing, irrigation, matrix fixation, tailings transportation,
discount rate, discounted value of future costs, and land costs.) The unit
costs are used to estimate the costs of applying various control methods to
the "average" tailings pile.
-------
The general control alternatives considered in this EIS are:
(1) Leaving the uranium mill tailings where they are, but restricting
access to the site. Particulate releases may be reduced by
stabilizing the surfaces of the pile.
(2) Covering the tailings pile to control radon-222 releases,
particulate releases, gamma radiation, and water contamination.
(3) Transporting the tailings to a new site, placing them in an
excavated pit with a surface impervious to moisture, and covering
the tailings to control radon releases, particulate releases, and
gamma radiation.
(4) Transporting the tailings for deep disposal to a nearby open-pit
or deep mine; or treating the tailings to remove radium (and
possibly other substances, such as thorium). This option provides
long-term control of radon releases, particulate releases, and
gamma radiation.
Disposal costs depend on the choice of option for general control, and
on the level of control within each option. For simplicity, we have
computed only the highest and lowest costs for each combination of a
general option and a specific radon control level. Table 6-1 summarizes
these costs. (See Appendix B for the details.)
The costs shown in Table 6-1 do not necessarily represent conditions
at any of the actual inactive sites, but they do cover all possible option
combinations. For example, the least expensive mehtod for satisfying
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TABLE 6-1
Ranges of Estimated Costs by Disposal Option and Radon Control Level
for the "Average^ Tailings Pile (in millions of 1978 dollars)
Disposal Option
450
100
-Radon-222 Control Level
10 5
. 1 and below
1. No control except
Fencing $.8 to 1.4
Surface stabilization $.5 to 3.6
I
CO
2. Cover to control radon
3. Below grade
$ .6 to 4.3 $ .8 to 5.4 5 .9 to 5.8 $1.0 to 6.3 $1.0 to 7.0
$5.4 to 11.2 $5.8 to 12.5 $5.8 to 12.8 $6.0 to 13.3 $5.7 to 13.9
4. Other
Radium concentration
Deep disposal
$69.2 to 75.7
$6.9 to 57.6
asphalt cap used
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control options 2 and 3 (for all radon control levels) assumes that
vegetation will be used for surface stabilization, and that neither
irrigation nor the purchase of a suitable top soil will be required. The
most expensive surface stabilization method under control options 2 and
uses riprap, or large stones.
Radiological protection and measurements costs associated with
performing disposal operations are not included in Table 6-1 or
Appendix B. These cover such operations as radiological monitoring of
workers, controlling pollutant releases while moving or grading a tailings
pile, surveying and sampling contaminated soil, and cleaning transporta-
tion vehicles. Estimating such costs is difficult because neither the
length of time that disposal operations will require nor the radiological
survey and analysis procedures have been set. Based on data provided by
Smith and Lambert (SM 78), however, we estimate that operational
radiological procedures will add about $150,000 (1978) to the disposal
costs of the "average" pile for each year disposal operations are
performed.
6.2 Estimated Health Benefits
The benefits of any disposal option depend on how much the option
reduces potential harmful effects, and for how long. The first option —
control limited to fencing, or surface stabilization and a fence — would
not reduce radon releases from the tailings to the air or water
contamination. Controlling access to land near the pile would reduce
6-4
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doses only to those few people who might otherwise live or work there.
Even this limited benefit would depend on institutional control and should
not be expected to last for more than a few centuries.
Benefits under the second option — covering the tailings at the
existing site — would be directly proportional to the degree of reduction
in radon releases. For example, reducing an uncontrolled radon release
rate of 450 pCi/m2-sec to 10 pCi/m2-sec would avert about 98% of the
potential effects of radon emitted from the uncontrolled pile.
Controlling radon releases to any significant degree would also prevent
release of particulates and reduce direct gamma radiation to negligible
levels. Suitable covers will protect surface and ground water by limiting
precipitation infiltration. Each site's characteristics would determine a
need for more specific water protection methods.
The third option — moving the tailings below grade, with a liner if
needed ~ would specifically control potential ground and surface water
hazards.
The fourth option is either acid leaching to concentrate the
radium(l), which would then be disposed of using special procedures
(DRemoval of additional radioactive materials, such as thorium and
uranium, could extend the period over which radioactive hazards are
controlled indefinitely.
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(see Appendix B), or deep disposal of the mill tailings. In principle,
this would provide the best prospect for long-term control of all the
options, but its praticality is the most uncertain.
In describing these benefits, we assume the control methods will
perform as expected. Table 6-2 summarizes the presumed benefits of the
various control options.
6.3 Longevity of Control
The ultimate objective is to assure control for as long as the
material is potentially hazardous, but we cannot reasonably expect
instutional control to last for more than a few hundred years. Lasting
effectiveness depends on physical disposal methods, proper consideration of
site conditions, and verification of disposal performance over the short
term. Beyond the period that control may reasonably be expected to endure,
chance or natural events becomes the determining factor.
Estimated control costs depend more on the method than on the degree
of radon control. The range of costs using different methods for a given
radon control level, in other words, is greater than the range of costs for
different radon control levels. The costliest methods generally would
provide control for the longest periods of time. Therefore, longevity may
be the primary factor in determining the actual cost of control.
6-6
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TABLE 6-2
General Post-Disposal Benefits of Disposal Options
Disposal Option
Benefits of Control
CTt
-J
1. No control except fence
2. Cover existing surface site
to limit Radon Releases
to: 100 pCi/m'-sec
10 pCi/B2-sec
5 pCi/m2- sec
2 pCi/m2-sec
0.5 pCi/mz-sec
Radon Particulates
Minimal benefit Minimal benefit
78Z All
of health effects avoided Health Effects
avoided
97.81 avoided
98.9Z avoided
99. 6Z avoided
99. 9Z avoided
Gamma Radiation Surface/Ground Water
Minimal benefit No benefit
All Some ancillary control
Health Effects through limiting
avoided precipitation infiltration
3. New site, below grade,
with liner if needed
4. Deep disposal or
acid leaching
Same as Option 2
1001
of health effects
avoided
Same as Option 2
Same as Option 2
Same as Option 2
Same as Option 2
Same as Option 2, plus
specific control of
potential ground and surface
water contamination
as Option 3
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Some disposal methods should last much longer than others. In
general, the thicker the cover, the longer the control. Thin covers of
artificial materials can greatly reduce radon releases but probably
wouldn't last very long. Stabilizing a tailings pile's surface against
wind and water erosion is a key factor in control longevity for disposalat
or near the Earth's surface. Stabilization requires careful site
selection and durable surface treatments. Disposal in a suitable location
deep underground appears to be a better way to avoid disruption of
tailings by natural events or people.
Below-grade disposal should be less subject to erosion than disposal
above grade. Since all the tailings piles at inactive sites are now above
grade, disposing of them below grade generally would mean choosing new
locations. This would present opportunities for finding particularly
suitable sites. In practice, however, conditions specific to each site
can blur these distinctions. At some sites, above-grade disposal
techniques may offer stability as good as that of below-grade disposal.
The longevity of any control method is difficult to quantify. Certain
methods should last longer than others, but experience with all control
methods is quite limited, especially considering the time that tailings
will remain hazardous. We would expect above-grade disposal to be
effective for hundreds to thousands of years; below-grade disposal,
thousands of years; and deep disposal, tens of thousands of years or
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more. Since longevity can only be described in broad terms, it is
impossible to relate the costs of specific long-lasting control methods
directly to estimates of the adverse health effects they will avoid. The
goal, however is to isolate tailings for as long as may reasonably be
done, avoiding future harm at least for that period.
6.4 Environmental Impacts of Control^
Cleanup, transportation, and final disposal of tailings will have an
adverse effect on the environment. Excavating and hauling tailings, for
example, may increase airborne particulates, though attention to control
of dust will reduce the problem. Radon-222 releases might also rise
temporarily as tailings are uncovered or piled in a new physical
arrangement. Surface runoff and other natural forces may increase
erosion. Tailings or other contaminated materials will probably spill,
and good housekeeping practices will be needed to assure they are cleaned
up and not spread around the environment.
Cleanup of contaminated land will require hauling material to a
disposal site, increasing road traffic, dust, noise, fumes, and the
possibility of accidents. Moving tailings to a new location will incur
similar risks. Disrupting vegetation at a new site, or obtaining material
to cover the tailings, produces an adverse impact.
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All of these effects will be temporary. Compared to the long-term.
impact of uncontrolled tailings, these temporary effects, if reduced as
much as is practical, could be considered negligible.
6.5 Occupational Hazards
The workers who carry out the tailings controls will face hazards.
Workers who clean and move uranium tailings will be exposed to more gamma
radiation and radioactive airborne particulates than most other workers in
earth moving occupations. Normal health physics procedures to control
radiation and exposure will have to be employed (HA Ip). Hazards from
trucks and other earth-moving equipment will be similar to those from any
large-scale earth-moving project. Any occupational hazards will be
temporary, and can be considered negligible compared to the long-term
impact of uncontrolled tailings.
6.6 Local Economic Considerations
The possibility of economic gains to communities near the tailings
sites offsets the temporary adverse environmental impacts and occupational
hazards to an extent. The cleanup activities may provide temporary jobs
to unemployed workers. Local business activity may increase. The
community may gain the use of previously contaminated land and
structures. The disposal sites, however, will be licensed by the NRC,
which may limit or prohibit their public use. Since public funds spent to
control tailings will be unavailable for other uses, local economic gains
may be offset by dampening of other national economic sectors.
6-10
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References for Chapter 6
(HA Ip) Hans, J.M., Jr. Burris, E., Gorsuch, T., "Radioactive Waste
Management at the Former Shiprock Uranium Mill Site,"
Environmental Protection Agency Technical Note (in preparation;.
(SM 78) Smith, C. Bruce and Lambert, Janet A., June 1978, "Technology and
Costs for Cleaning Up Land Contaminated with Plutonium, in
"Selected Topics: Transuranium Elements in The General
Environment," U.S. Environmental Protection Agency, ORP/CSD-78-1.
6-11
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7: CONSIDERATIONS FOR CLEANUP OF CONTAMINATED LAND AND BUILDINGS
7.1 Introduction
Because land areas have been contaminated by wind- and water-borne
tailings, tailing diapoaal will include disposal of some contaminated
soils. If the control method chosen for disposal of a tailings pile
requires moving it, contaminated soil beneath the pile must also be
disposed of.
Buildings, too, have contaminated, by tailings carried by wind and
water and used as fill under and around the structures. Buildings once
part of the mill operation are also contaminated to various degrees.
7-2 Off-Site Contamination
Sec. 3.1 discussed a study to locate tailings in communities near
inactive processing sites. Table 3-5 indicates that of 22,213 radiation
anomalies (a gamma radiation level higher than normal) detected in the
regions surveyed with a mobile gamma radiation scanner, 6,518 of these were
traced to uranium mill tailings, 7,889 to other radioactive sources
(including luminous dial alarm clocks and mined uranium), and 955 to
naturally occurring radioactivity; 6,851 anomalies were of unknown origin
(OR 73).
These data include Grand Junction, Colorado, where, because tailings
were used on a large scale in construction, a Federal/State remedial action
program for affected buildings is underway. In Mesa County, where Grand
Junction is located, over 25,000 locations had been screened as of
October 15, 1978,
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to Identify possible tailings (GJ 79). More than 6,000 locations had some
tailings on the property; the rest had none. Of the locations with
tailings, about 800 are expected to receive remedial action, ?00 more
qualify for remedial action but the property owners probably will not
apply, and the approximately 5,000 remaining have radiation levels below
the program criteria for remedial action. In Mesa County tailings also
were used to build sewer and water lines, streets, nnd other projects,
which will be eligible for remedial actions under PL 95-604.
Gamma radiation surveys established the extent of contamination near
the inactive processing sites from wind and water erosion of tailings piles
(Table 3-6). More than 5,000 acres had gamma radiation above the normal
background had gamma radiation above the normal background level. The area
with gamma radiation levels equal to or greater than 10 uR/hr above
background is more than 2,000 acres. This figure omits the surface areas
of the tailings piles themselves, about 1,000 acres.
The seriousness of off-site contamination depends on the degree of
contamination and the potential exposure to people. The amount of land and
number of buildings that will require cleanup will be determined by the
cleanup standards selected.
7.3 Potential Hazards of Off-site Contamination
The greatest hazard posed by tailings on open lands is their potential
to increase levels of radon decay products in buildings. Exposure to
7-2
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direct gamma radiation and contamination of drinking water and food may
also occur, but generally will be of less concern.
There is a health risk associated with radon decay products. Their
concentration in an existing or future building will depend on the radium
concentration in the soil under or adjacent to it. So many other factors
affect the indoor radon decay product concentration, however, that
establishing a useful correlation with the radium in soil is difficult.
Nevertheless, Healy and Rogers (HE 78) have anaylzed exposure pathways due
to radium in soils, whether occurring naturally or as contamination. They
argue that one might expect indoor radon decay product concentrations of
0.01 WL for soils with radium concentrations of 1 to 3 pCi/gm to a depth of
one meter or more. NRC estimates (NR 79) that 3 to 5 pCi/gm of radium can
cause indoor concentrations of 0.01 WL. Both of these calculations are
approximations, but radium concentrations near the lower end of these
ranges correspond to common natural soil conditions. Therefore, where
indoor radon decay product concentrations are only slightly elevated,
tailings may not be the dominant cause, so remedial action for tailings may
have little beneficial effect. Moreover, cleaning contaminated open land
will not eliminate elevated radon decay product levels in future buildings,
though it generally will reduce the frequency with which they occur.
Tailings also emit gamma radiation, which can penetrate the body from
the outside. We expect that the indoor radon decay product concentration
standards generally will be met by removing tailings from the building, and
7-3
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this will eliminate any indoor gamma radiation problem. For some
buildings, however, removing the tailings completely may be impractical
(more for engineering reasons than for cost). Alternatives, such as air
cleaning, improving ventilation, or applying sealants to the walls and
floors, are available. If these are used, standards will be needed to
limit gamma radiation exposure of the occupants.
Natural or contaminated soils with radium concentrations of 5 pCi/gm
through a depth of several feet can have gamma radiation exposure rates of
about 80 mR/yr (NC 76). Exposure rates are proportionately higher or lower
for other radium concentrations, and decrease as the layer of
radium-containing material becomes thinner or is covered over by other
materials. The potential for causing elevated indoor radon decay product
levels in future buildings on such soils also depends on these factors.
Therefore, cleanup standards for open land should consider both the radium
concentration and the thickness of the contaminated soil.
Each gram of natural uranium contains 330,000 pCi of U-238 and 15,000
pCi of U-235. Because it appears in relatively small proportion, U-235 and
its radioactive decay products usually may be ignored in evaluating the
hazard of uranium tailings. The dominant hazard from most tailings is from
decay products of U-238, including radium-226 and its decay products.
Other radioactive substances in the tailing will ordinary pose much less
risk to health than that from radium-226.
7-4
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The total protection that a standard based on radium-226 provides
depends on the extent to which radium has been separated from other
radioactive substances, such as thorium and the U-235 decay products,
during ore processing. If significant separation occurs, radium-226
concentration in the residual material may not adequately measure the
radiation hazard. For example, thorium separates from radium in uranium
mills using the acid leach process. Although thorlum-230 and radium-226
occur in ore in about equal amounts of radioactivity, thorium compounds are
more soluble in acid. Therefore, thorium radioactivity concentrations in
the wastewater may be thousands of times higher than for radium, and more
thorium may then seep through the pile to the soil below (RA ?8). However,
chemical interaction of thorium with the soils should retard further
movement (GS 80).
At least one of the processing sites covered under Public Law 95-604
(Canonsburg, Pa.) may have tailings containing higher than usual
Proportions of U-235 decay products. Although little is known about the
environmental pathways and biological effects of these radionuclides,
site-specific information on their concentrations suggest that they are
unlikely to be a determining factor in cleanup decisions (DO 78). The
U-238 decay products are present in greater amounts.
7.4 Remedial Actions and Costs
The only remedial action that would eliminate the hazards from
contaminated land and buildings would be to remove uranium mill tailings
7-5
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from under and around buildings and from open land, and to dispose of them
along with the tailings pile. The cost and complexity of removing tailing3
from buildings depends on the amount of tailings and their location
relative to the structure. Tailings used as backfill around the outside of
a foundation, for example can be removed easily at relatively low cost.
Removing tailings from under a floor or foundation, on the other hand,
entails breaking up concrete to reach the tailings, a costlier and more
complex procedure. In 1972, Congress enacted PL 92-314, authorizing
remedial action for buildings in Grand Junction, Colorado, affected by that
community's extensive use of tailings in construction. Experience gained
through seven years of that program illustrates the remedial action costs
that may be incurred for similar situations in other places under PL
95-604. In the Grand Junction remedial action program, the average cost to
treat a residential structure has been about $13,500, ranging from $540 to
$41,000
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7.5 Previous Standards for Indoor Radon Decay Product Concentration
Government agencies of the United States and Canada have previously
published remedial action criteria for radon decay product concentrations
in buildings.
The U.S. Surgeon General's 1970 remedial action guidance for Grand
Junction, Colorado, applies to buildings on or containing uranium mill
tailings (PE 70). EPA's guidance to the State of Florida applies to
buildings on radium-bearing phosphate lands (FR 4H). Each set of guides
has two levels: 1) Radon decay product concentrations above the upper
level require action; 2) those below the lower level do not; 3) between
these levels, local factors determine the action required.
The Surgeon General's Guides are implemented in the Department of
Energy's regulations for remedial action at Grand Junction, Colorado (10
CFR 712). In effect, they adopt the lower level as an action level for
schools and residences, and the midpoint between the lower and upper levels
as an action level for other buildings. This difference in action levels
recognizes that children should have added protection, and that people
occupy residences and commercial building for different periods. For radon
decay product concentrations these actions levels are 0.01 WL and 0.03 WL,
respectively, above background. The average background indoor radon decay
Product concentration determined for use in the Grand Junction remedial
action program is 0.007 WL.
7-7
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The Canadian cleanup criteria (AE 77) and the EPA recommendations for
residences on phosphate lands in Florida require remedial action for indoor
radon decay product concentrations greater than 0.02 WL (including
background). The EPA guidance further recommends that concentrations below
0.02 WL be reduced further recommends that concentrations below 0.02 WL be
reduced as low as can be reasonably achieved. Reductions below 0.005 WL
above the average normal background (for nearby lands in Florida) of O.OOU
WL are not generally justifiable in the Florida phosphate lands. For
Florida, then, EPA has in effect recommended remedial action above 0.2 WL:
stated that action is generally unjustified at concentrations less than
0.009 WL; and left action at intermediate levels to the judgment of local
officials.
Surveys have been conducted to find buildings which may be affected by
tailing for which remedial actions may be conducted under PL 95-60M. These
surveys show a variety of affected structures, whose elevated radiation
levels have several different causes. The total number of buildings that
will be eligible under PL 95-604 is not fully established, but we believe
they are fewer or comparable in number to those in Grand Junction, that is,
several hundred.
7'6 Normal Indoor Radon Decay Product Concentrations
The indoor radon decay product concentration of a building affected by
tailings is the sum of contributions from tailings and from the natural
environment. These contributions cannot be distinguished from one
7-8
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another. Knowledge of the characteristics of radon decay product
concentrations in normal buildings is very useful in eciding the best form
for a remedial action standard and in choosing a practical action level.
The most complete studies of normal indoor radon decay product
concentrations in the United States were performed on buildings in Grand
Junction, Colorado (PE 77), New Jersey and New York (GE 78), and Florida
(FL 78). The samples and measurement techniques of these studies are not
exactly comparable, however. The New Jersey-New York buildings studied
were residences, mostly single-family one-or two-story buildings. The
Grand Junction sample was mainly houses, about half of which had basements
(CO 79). The reported Grand Junction data are for the lowest "habitable
portion" of the building. The Florida sample is single-family houses
without basements.
Some results from these studies are summarized in Table 7-1. In all
cases, the reported concentrations are the average of measurements taken
over a year. The data indicate wide variations in normal indoor radon
decay product concentrations within each sample, even for a relatively
uniform sample of buildings. Furthermore, the New Jersey-New York data
show that concentrations at ground level are about half of those in the
basement. (An unpublished analysis of the G-and Junction data shows a
similar effect (CO 79).)
Many buildings in the western United States, where most of the sites
covered under PL 95-604 are located, have basements. For
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TABLE 7-1
Average Annual Radon Decay Product Concentrations
in Normal Buildings
Grand Junction. Colorado (a)
Sample: 29 buildings, mostly houses, about half with basements.
Range: 0.002-0.017 WL
Median: 0.007 WL
Above 0.01 WL: 30?
Above 0.015 WL: 10% (approx.)
New Jersey-New York(b)
Sample: 21 houses, mostly single-family with full basements.
Cellar First Floor
Range: 0.0017 - 0.027 WL -
0.0017 - 0.013 WL
Median: 0.008 WL 0.004 WL
Above 0.01 WL: 14056 8$
Above 0.015 WL: 20J6
Florida(c)
Sample: 28 single-family residences, without basements.
Range: 0.001 - 0.012 WL
Median: 0.0035 WL
'bove 0.01 WL: 3?
Above 0.015 WL: 0%
(a)References (PE 77) and (CO 79).
(b)Reference (GE 78).
(c)Reference (FL 78).
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these buildings in particular, the most important conclusions we draw from
these studies are the following:
1. Normal indoor radon decay product concentrations vary greatly.
2. Concentrations greater than 0.01 WL in a useable part of a normal
building are commonplace.
3. Though less common, normal concentrations greater than 0.015 WL
are not rare.
7.7 Practicality of Alternative Remedial Action Standards for Buildings
Experience in the Grand Junction program aids in estimating the scope
of a cleanup program for tailings under alternative remedial action
criteria. Table 7-2 gives the Grand Junction program's results (CO 79)
for buildings having tailings for which radon decay product measurements
have been made. For residences and schools, the remedial action level is
0.01 WL above background. Among the 463 residences and schools sampled,
217 were eligible for remedial action. If the action level had been 0.005
WL rather than 0.01 WL the number eligible would have risen to 278, a 28$.
Table 7-2 also shows that 60 residences and schools have been treated
but not yet brought below the action level. Had the action level been
0.005 instead of 0.01 WL above background, 111 rather than 60 would need
further remedial work.
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TABLE 7-2
Experience with Grand Junction Remedial Action Program
Total
Non-eligible
Residences and Schools 246
Other 76
Number Above
0.01V7L + Background
0
10
Number Between
0.005WL and 0.01WL
Above
61
12
Post-remedial
Residences and Schools 217
Other 35
60(c)
17
51
9
(a)Modified from reference (CO 79).
(b)Table entries are numbers of buildings having tailings for which
radon decay product measurements have been made.
(c)Buildings for which remedial actions have not been completed.
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Table 7-2 ."hows that 40 or 52 additional buildings other than
residences and schools would have been eligible if the action level for
them had been 0.01 WL or 0.005 WL above background, respectively, rather
than the 0.03 prescribed. This is an increase of lUt or 149*,
respectively, in the program for that category of buildings. The table
also shows that at the'lower action levels additional work would be needed
for 1? to 26 of the buildings other than residences and schools on which
remedial action has already been performed.
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References for Chapter 7
(AE 77) Atomic Energy Control Board of Canada, "Criteria for Radioactive
Cleanup in Canada," Information Bulletin 77-2, April 7, 1977.
(CO 79) Colorado Department of Health, October 3, 1979, Letter from A.
Harold Langner, Jr., and subsequent conversations.
(DO 78) Department of Energy, Report No. DOE/EV-0005/3, April 1978.
(PB 76-78) Ford, Bacon, and Davis, Utah, Inc., "Phase II-Title 1,
Engineering Assessment of Inactive Uranium Mill Tailings," 20
f H?°rtS for Department of Energy Contract No.
-1)-1658, 1976-1978.
(FB 79) Ford, Bacon, and Davis, Utah, Inc., July 1979, "Engineering
Evaluation of the Former Vitro Rare Metal Plant, Canonsburg,
Pennsylvania" and "Engineering Evaluation of the Pennsylvania
Railroad Landfill Site, Burrell Township, Pennsylvania."
(FL 78) Florida Department of Health and Rehabilitative Services, "Study
of Radon Daughter Concentrations in Structures in Polk and
Hillsborough Counties," January 1978.
(FR 4!4) Federal Register HHr p 38664-38670, July 2, 1979.
onn n ' A'J" "The Distribution of Ambient
Radon and Radon Daughters in Residential Buildings in ^he New
StlonYT;: ArY PreS6ntefi at the Symposia8 o'the Natural
Radiation in the Environment III, Houston, Texas, April 1978.
(GJ 79) Grand Junction Office, February 1979, "Progress Report on the
Grand Junction Uranium Mill Taiiings Femedial ^^ p „
U.S. Department of Energy Report DOE/EV-0033.
(GS 80) U.S. Geological Survey, 1980, "Isolation of Uranium Mill Tailings
the ^sphere," by" Edward
(HE 78) Healy, J.W., and Rodgers, J.C., October 1978,
Solls-"
(NC 76) National Council on Radiation Protection and Measurements
December 1976, "Environmental Radiation Measurements," NCRP Report
No. 50.
7-1U
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(NR 79) U.S. Nuclear Regulatory Commission, April 1979, "Generic
Environmental Impact Statement on Uranium Milling," Volume II,
App. J, NUREG-0511.
(OR 73) Office of Radiation Programs, March 1973, "Summary Report of the
Radiation Surveys Performed in Selected Communities," U.S.
Environmental Protection Agency.
(PE 70) Letter by Pau J. Peterson, Acting Surgeon General to Dr. R.L.
Cleere, Executive Director, Colorado State Department of Health,
July 1970.
(PE 77) Peterson, Bruce H., "Background Working Levels and the Remedial
Action Guidelines," in the Proceedings of a Radon Workshop,
Department of Energy Report No. HASL-325, July 1977.
78) Rahn, P.H., and Mabes, D.L., "Seepage from Uranium Tailings Ponds
and its Impact on Ground Water," Proceedings of the Seminar on
Management, Stabilization, and Environmental Impact of Uranium
Mill Tailings, July 1978, the OECD Nuclear Energy Agency.
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8: SELECTING THE PROPOSED STANDARDS
In PL 95-604, the Congress stated its findings that tailings "may pose
a potential and significant radiation health hazard to the public" and that
"every reasonable effort should be made to provide for stabilization,
disposal, and control in a safe and environmentally sound manner of such
tailings in order to prevent or minimize radon diffusion into the environ-
ment and to prevent or minimize other environmental hazards from such
tailings." The Environmental Protection Agency was directed by Congress to
set "standards of general application for the protection of the public
health, safety, and the environment" for such materials. The legislative
record also shows that Congress intended that these standards apply to all
sites rather than be site-specific.
The Committee report on the Uranium Mill Tailings Radiation Control
Act expressed the intent that the technologies used for remedial actions
should be effective for more than a short period of time: "The Committee
does not want to visit this problem again with additional aid. The remedial
action must be done right the first time" (House of Representatives Report
95-1480, Part 2).
Our proposed standards (Appendix D) are meant to ensure a long-lasting
solution.
Disposal Standards
Our analysis of the health effects from tailings piles shows that they
mainly caused by radon emissions into the air. Environmental
-------
contamination also can occur if toxic chemicals from tailings enter surface
or underground water, though this depends strongly on individual site
characteristics.
8.1.1. Radon Standard
From our analysis of health effects of tailings piles, we conclude
that:
a. Lung cancer caused by radon's short-lived decay products is the
dominant radiation hazard from untreated uranium mill tailings piles on
local, regional, and national scales. Effects of long-lived radon decay
products, of windblown tailings, and of direct gamma radiation from the
piles are much less significant.
b. Individuals near a pile bear much higher radiation risks than those
far away. We estimate, for example, that individuals continuously living
one mile from a large pile wouid have about 20Q times gg ^^ & ^^ Q£
a fatal lung cancer (7 in 10,000 versus 3 in 1,000,000) caused by radon
products from the pile as would individuals living 20 miles away
(Table 4-2). At some of the piles, where people live even closer than one
mile, the increased risk of developing lung cancer over a lifetime is as
high as 4 chances in 100 (Table 4-3).
c. The total number of cancer deaths that a pile would induce depends
strongly on the size and locations of the local populations.
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d. Based on recent population data, all the 22 piles at inactive sites
we studied taken together may cause 40 to 90 deaths from lung cancer per
century among persons living 50 miles or more away from a pile. When local
and regional rates are added to these, the estimated total national effect
of all the 22 piles is about 200 premature deaths from lung cancer per
century, or an annual rate of about two deaths.
Part of the uncertainty in these estimates results from necessary
approximations in estimating the environmental radiation levels a tailings
Pile produces, and the doses people will receive. Additional uncertainty
comes from our incomplete knowledge of the effects on people of these
generally low exposures.
Our estimates are based upon current population sizes and geographical
distributions. Overall increases in national population would raise the
estimated national effects in approximate proportion. Development of new
Population centers near currently remote piles, and substantial growth of
cities already near one, would increase these estimates proportionately.
Unless radon emissions from the tailings piles covered under Title I
of PL 95-604 are greatly reduced, they might prematurely kill about 200
People per century into the indefinite future. Even for piles remote from
Population centers, equity for people living nearby and the possibility of
future development near the sites argue for control measures. A reasonable
effort to prevent or minimize radon emissions from piles is required under
PL 95-604.
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Methods for controlling radon emissions from piles are available. The
most straightforward methods call for burying the piles or covering them
with appropriate combinations and thicknesses of soils, and with erosion-
resistant surfaces. We believe the basic capabilities of these methods to
control radon releases, although largely untested, are understood. Other
methods may also be useful (Chapter 5, Appendix B, NRC's GEIS for Uranium
Milling (NR 79)).
From several perspectives, as discussed below, we find it reasonable
to reduce radon emission rates from tailing at inactive processing sites
from current values of several hundred pCi/m2-sec to a range more
characteristic of ordinary land. Typical natural emission rates are from
0.5 to 1 pCi/m2-sec, with variations up to several times these values not
unusual (NR 79).
Next, the form and numerical values of the standard must be fixed.
Three quantities will be considered as alternative basic units for the
standard: the radon release rate per unit area (expressed in pCi/m2-sec),
the total radon release rate (pCi/sec, or Ci/yr), and the dose or exposure
of actual or hypothetical individuals or populations (mrem/yr, person-
rem/yr, person-WLM, etc.).
We rejected a dose or exposure standard. It is cumbersome to
implement, with no compensating advantages except that it relates directly
to risk. One major purpose of the standard is to guide the design of
disposal systems. A dose or exposure standard would introduce uncertainty
8-4
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into this process, because radon release rates must be known before dose or
exposure can be estimated.
We also rejected a standard based on the total radon release rate.
Limiting the total radon release rate fails to take account of the great
differences in radioactivity among the piles (see Table 3-1). A single
limit on total radon release from all piles could place unreasonable burdens
on the disposal designs. A limit on release rate per unit area, however,
may readily be applied uniformly to all sites. Release rate per unit area
is also the most meaningful quantity for comparing the emission of a site
with that of normal land. Since radon release rates change with the
climate, however, the standard should address the average rate over a
year's time.
After considering the alternatives (see below) we have concluded
that the numerical limit on pile emissions, following disposal, should be
from about 0.5 to 2.0 pCi/m2-sec. When added to the radon released from
a normal earth covering, the disposal site emission rate would still be
within a normal range.(1) The risk for people living or working away
from the disposal site is a minor factor in choosing a standard within this
range, since 98% or more of their exposure to radon comes from other
sources (NR 79).
covering of average soil will contribute an additional 0.5 to
pCi/m2-8ec.
8-5
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Disposal sites generally will be large enough for small communities to
be built upon. It appears unlikely that a combination of emission,
residency, and construction factors would materialize that would create a
public health problem under a standard in the radon emission range we are
considering. The incremental risk associated with the choice of a control
level within this range appears small enough so that other factors should
also be considered.
Figure 5-1 shows that to control radon emissions by covering piles with
soil, the required covering thickness rises sharply(l) near a rate of
about 1 pCi/m2-8ec. These curves are based on theory and laboratory
tests; there has been no opportunity to test them against full-scale field
experience. If soil coverings should be less efficient in controlling
radon than the curves indicate, meeting a standard at the low end of the
radon emission range could be much more difficult and expensive than we
estimate. The gain in health benefit, moreover, would be marginal. We
therefore propose to allow a tailings release rate of 2 pCi/m2-sec rather
than a slightly lower figure, to allow for more technical flexibility in
implementing the standard.
We considered setting a higher or lower radon release standard.
Higher levels, from 10 to 40 pCi/m2-sec, perhaps, appear unjustified;
such emission rates can be lowered to 2 pCi/m2-8ec for about 10 percent
(l)Reducing emission from 10 to 9 pCi/m2-sec (a 10% reduction)
requires about 1cm of added soil; the same size emission reduction from 2
to 1 pCi/m2-Sec takes about 50 cm of added soil.
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additional cost.(l) With such elevated radon emissions, the probable
need for land-use restrictions adjacent to the disposal site would place a
continuing administrative burden on future generations.
We also find near total control of radon release from the tailings
unjustified. Incremental costs for achieving emission rates lower than
2 pCi/m2-sec rise faster than emissions drop, and any achievable health
benefits would be extremely expensive. Restricting land use near the
disposal site because of radon releases from the tailings is unneeded for
radon emission levels near 2 pCi/n»2-sec. We have found no administrative
or esthetic advantages in further reductions.(2)
The proposed standard typically would reduce radon emissions and their
possible effects by 99%. Measures that will cut down radon emissions this
much for at least one thousand years (see Section 8.1.5) will also eliminate
blown tailings and excess gamma radiation. Therefore, implementing the
(DThis assumes that covering the tailings with soils and clay is a
feasible method for radon control to an emission level of about
2 pCi/m2-8ec. Tailings piles vary widely in their size and radioactivity
content. Therefore, costs of applying the burial method or any other ade-
quate disposal technique will vary greatly among the piles. We estimated
Potential disposal costs for a variety of methods (see Chapter 6 and
Appendix B). For example, assuming the tailings would be taken to a new
site and buried in a shallow pit, we estimated the disposal cost for an
average pile as 6-13 million dollars (1978). Costs for some piles may be
Partially offset by the value of residual uranium that may be recovered by
reprocessing the tailings before disposing of them, or the reclamation
value of the original tailings site.
(2)However, PL 95-604 provides that after remedial actions are
completed, the tailings will be in Federal custody under license by the
Nuclear Regulatory Commission.
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radon control standard will virtually eliminate all the potential hazards
except water pollution.
8.1.2 Ground Water Standard
Since most of the inactive sites are in dry climates, much of the water
that may ever infiltrate them has probably already done so during active
operation of the mill. This probably is not true for all sites, and
standards for protecting ground water after disposal of the tailings are
needed.
Under the proposed ground water standards (Appendix D), after a
tailings pile is disposed of, it may not cause the concentrations of
certain pollutants in an underground source of drinking water to either
(1) exceed the contaminant level specified for that pollutant, or
(2) increase, where the background concentration of the pollutant already
exceeds the applicable specified contaminant level. An underground source
of drinking water is defined as an aquifer currently supplying drinking
water for human consumption, or an aquifer in which the concentration of
total dissolved solids is less than 10,000 milligrams per liter (FR 79).
The proposed ground water protection standards could be considered too
strict if implementing them would be unreasonably costly or if they would
be impossible to apply. Information available suggests that our proposals
are practical. The following sections discuss alternative approaches to
setting the standard, and describe the reasons for choosing the proposed
standards.
8-8
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Approach to Ground Water Protection
These standards are conditions for disposal of uranium mill tailings
from inactive processing sites, not ambient water quality criteria. We have
concluded that disposal of tailings should not degrade ground water beyond
levels that retain its fitness for direct consumption by people. We recog-
nize that ground water quality is also important for other reasons? its
effect on fragile ecosystems, for example, and irrigation. Other standards
may be appropriate to protect its usefulness for these other purposes. We
believe, however, that the prevention of adverse human health effects from
direct consumption of ground water should be foremost among several
objectives in protecting ground water quality.
Contaminants of Concern
Contaminant levels in the National Interim Primary Drinking Water Regu-
lations (NIPDWR) provide the best current guidance of adequate protection
levels for drinking water. However, we also considered whether the NIPDWR
cover all contaminants found in tailings, or contaminants that are not.
Except for fluorides, all the inorganic chemicals listed in the NIPDWR
nave been reported as present in tailings.(1) However, uranium mill
tailings are not significant sources of organic chemicals, microbiological
contamination, or man-made radioactivity, so these categories of the NIPDWR
can be disregarded.
--A«eBe !««»»..»* chemicals are «8«™c»
mercury, nitrate, selenium, and silver.
it to radioactivity limits in the NIPDWR.
8-9
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Other substances possibly harmful to human health were not included in
the NIPDWR due to their relative rarity in drinking water systems, the lack
of analytical methods, the high costs of monitoring, or the lack of toxicity
data. Several such substances are present in leachate from tailings. We
have reviewed these substances (see Sections 4.8.2 and 4.8.3) and have
included two — molybdenum and uranium ~ in our proposed standards, because
of the seriousness of their toxic effects on humans, animals, or plants,
their abundance in the tailings, and their expected environmental mobility-
We have also considered the contaminants addressed by the National
Secondary Drinking Water Regulations (NSDWR). The NSDWR (40 CFR 143)
represent EPA's best judgment of the standards necessary to protect
underground drinking water supplies from adverse odor, taste, color, and
other esthetic changes that would make the water unfit for human consump-
tion. We decided, however, not to include the contaminants identified in
the NSDWR in the proposed standards. The list of contaminants we are
including covers the most hazardous substances in many different chemical
forms. Conditions that control these toxic substances will also control
many other substances.U) Me expect scientific analyses and predictions
based upon them to be the primary means of demonstrating compliance with
8-10
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the standard, and do not wish to complicate that task by including
nonessential requirements.
We also considered for coverage in these standards the pollutants
covered in the publication "Quality Criteria for Water" (EP 76). "Quality
Criteria for Water" recommends levels for water quality according to the
objectives of Section 101(a) and the requirements of Section 304(a) of the
Clean Water Act. Its primary purpose is to recommend levels for surface
water quality that will provide for the protection and propagation of fish
and other aquatic life, and for recreation. While several health-related
substances that could be present in tailings leachate are listed, the
recommended limits are geared to protecting aquatic life and are not
appropriate for ground water. Further, the recommended limits are written
as guidance in developing standards and not as standards themselves.
Therefore, we decided that this list was inappropriate for these standards.
of Contamination
The proposed standards require a reasonable expectation that releases
from tailings piles will not cause:
(a) The concentrations of certain contaminants in ground water to
exceed specified levels, or
(b) An increase in the concentration of any of those contaminants in
ground water where the existing (upstream) concentration exceeds the
specified level.
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The first requirement, (a), protects water that can be used as
drinking water without treatment under current regulations, except that we
have added coverage of molybdenum and uranium. The proposed concentration
level for molybdenum is appropriate for avoiding toxic effects in humans,
in accordance with the recommendations of a recent report to EPA (CH 79)•
The proposed standard for uranium is the level for which our estimate of
bone cancer risk is about the same as the estimated bone cancer risk for
radium under the NIPDWR. The second part, (b), protects ground water
already at or above the maximum contaminant level, by preventing increases
in contaminant concentrations.
We considered several arguments for more lenient standards than those
proposed: (a) The increased disposal cost might be greater than the value
of the threatened resource; (b) treating the water after contamination
would be a more efficient way to remove undesirable substances; and
(c) some of the allowable levels are commonly exceeded in ambient or native
ground water, effectively resulting in a nondegradation standard for those
aquifers.
We respond to these arguments as follows:
(a) We are not required to balance disposal costs against the value
of ground water resources, nor can the "value" be determined for an
indefinite future. Moreover, we do not know and probably cannot determine
a useable relationship between disposal costs and specific ground water
protection requirements. We believe the proposed standards are a
reasonable approach to ground water protection.
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(b) Treating ground water after contamination may be efficient when
it is done, but undoubtedly some people will continue to use untreated
water. We believe it preferable, and more consistent with the intentions
of Congress, to minimize the need to treat water. Tailings piles disposed
of in accordance with the proposed standard should not cause ground water
"problems" for people in the future. We cannot be as sure that more
lenient standards will provide adequate protection.
(c) We expect that our standards often will amount to nondegradation
standards, because native levels of dissolved substances in aquifers where
the piles are located are often not very low. We have no compelling reasons
to allow tailings to increase these levels, however. If the native water
quality itself may present problems for future users of increasingly scarce
ground water resources, why should disposal of these tailings piles be
allowed to worsen the situation?
Reasons we considered for adopting more stringent standards include:
(a) tailings disposal is only one of several sources of ground water con-
tamination, and each source contributes to the overall rise in contaminant
levels; (b) future research may find that lower levels are necessary to
adequately protect health; (c) some agricultural, industrial and other
important uses of ground water may be impaired; and (d) ground water is
often consumed without treatment, so more stringent standards would require
less reliance on monitoring and treatment before domestic usage.
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Our analysis of these reasons follows:
(a) The proposed standard does recognize that an aquifer may be
polluted by several sources. Where existing ground water contaminant
concentrations exceed the levels specified in the proposed standards, the
disposal system should be designed not to allow contaminant levels to
increase at all. Future sources of contamination, when added to releases
from tailings, may cause increases in earlier concentration levels. If the
resulting increases are large, however, under the standards contaminants
from the tailings will not be the dominant contributors to the increases.
Releases from the tailings, when added to contaminants from other sources,
could be the major factor in causing small increases in concentrations, but
small increases are not very significant.
(b) Since tailings are mainly the ground up residues of rock,
contaminants that may leach from them into water are already present in
varying degrees in native ground and surface waters. People have always
consumed water containing these substances, so it appears unlikely that
these substances will be found in the future to be very much more toxic
than we presently believe. Further, our standards apply only to the
relatively few sites covered by the Title I program Of PL 95-604. Under
the circumstances, any harm that might be avoided by stricter standards is
both small and speculative.
CO Our proposed standards would allow very good quality water to be
slightly degraded. If and when this occurs some uses of the water might be
-Paired. Such impairments are speculative. In view of the limited number
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°f sites to which the standards apply and the degree of protection they
afford for good quality water, the possibility of such impairments does not
appear to be a serious defect in the proposals.
(d) Our standards are designed to protect people who may directly con-
sume the water. Whatever the standards may be, the purpose of monitoring is
to determine actual contaminant levels. The extent of necessary monitoring
at any site should be determined in part by considering the possibility of
unexpected failures of the disposal system and other site-specific factors.
lt seems doubtful that stricter standards would have much influence on such
the Standard is Applied
Another issue regarding ground water protection is the physical point
at which the standard should be applied. At what point in the aquifer, in
other words, does contamination from tailings constitute noncompliance?
1116 Places we considered are the site boundary, the waste boundary, or some
8Pecifie
-------
Applying the standard to the waste boundary would minimize the affected
area. However, the tailings at inactive processing sites have, to some
extent, merged with their immediate surroundings, so the waste boundary may
be hard to define. More significantly, a standard applied so near the waste
may be difficult to meet at some otherwise adequate existing sites. Where
the standards might be exceeded only in the immediate neighborhood of a
pile, the cost of liners and re-siting to avoid the violation appears to be
unjustified. To avoid these higher costs and their small benefits, a strict
standard should apply only beyond some distance. We propose this distance
to be 1.0 kilometer from the smallest practical boundary of the waste when
an existing tailings site is used for disposal. A smaller distance of
application might not serve our intended purpose of avoiding large expedi-
tures for very little gain, and we believe that a much larger distance would
be insufficiently protective. However, if tailings are moved to a new
disposal site, for whatever reason, then new opportunities for site selec-
tion and preparation become available. For new sites we propose to apply
the standards 0.1 kilometer from the waste boundary. In effect, this is as
protective as applying it at the waste boundary, while allowing some
benefit from sorption and dilution in immediately adjacent ground, in case
small leaks occur.
Drinking Water Source
The choice of the 10,000 mg/1 total dissolved solids measure for
usable aquifers follows EPA's general policy that ground water resources
below that concentration be protected for possible use as drinking water
sources. This policy is based on the Safe Drinking Water Act and its
8-16
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legislative history, which reflects Congressional intent that aquifers in
that class deserve protection.
8.1.3. Surface Water Protection
Wind, rain, or floods can carry tailings into rivers, lakes, and
reservoirs. Pollutants may also seep out of piles and contaminate surface
waters. We believe that the standards should limit the effects of these
processes on surface water quality. We expect that implementing the radon
emission limits and the ground water protection requirements will greatly
reduce the potential for contamination of surface water.U> A pile with
severely restricted radon releases will not be able to release particulates
to wind or water. Similarly, the ground water protection requirements imply
limited water flow through the pile, which limits flow to the surface as
well as underground. Thus, implementing the radon emission and ground water
standards may protect surface water. To assure adequate protection, how-
ever, we propose to require that surface water not be degraded by tailings
after disposal of the piles. This means that the tailings disposal site
should not cause increases in the concentration of harmful substances in
surface water.
We considered banning any release of pollutant, to surface water.
This may be more difficult to implement than the selected standard,
(OHowever, .recent studies (•-.•-^".S?contaminant, upward,
Processes occurring in tailings piles «n° ._,;_ designer, must
perhaps even tto-*«« «"»»•. STSkSSToFESw ««~«»
carefully consider this possibility, ine w F .
intensively investigating a variety of disposal methods.
8-17
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however, since it would require showing that not even microscopic releases
will occur. Our chosen standard requires any potentially harmful
contaminant streams from the tailings to have lower concentration of
contaminants than the surface water they may enter. The standard applies
to all harmful contaminants from tailings, and some of them are certainly
present only in very low concentrations in surface water. Satisfying the
standard will therefore require strict limits on releases to surface water
of at least these latter substances. In practice, we expect that the means
used to inhibit pollution of surface water by harmful contaminants that are
already present in low concentrations will restrain the movement of most
other substances as well. The standard, then, will be very protective of
surface water.
We have chosen to apply the standard to "navigable waters" as defined
in an EPA Federal Register notice (44 F.R. 32901, June 7, 1979). This
definition was adopted for EPA's regulations under the National Pollutant
Discharge Elimination System, 40 CFR 122.3(t). In essence, it includes all
surface waters the public may travel on, enter, or draw food from.
However, there is no formal relationship between EPA's standard under
PL 95-604 and regulations under the National Pollutant Discharge
Elimination System; either nay be changed without affecting the other.
8.1.4 Remedial Action for Existing Ground Water Contamination
There is evidence of limited ground water contamination at some of the
inactive sites, but the prospects for long-term contamination have not been
fully assessed. The proposed ground water protection standards apply only
8-18
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to releases from tailings that may occur after disposal of the piles. It
may sometimes be possible to improve the quality of an already-contaminated
aquifer, but we believe a generally applicable requirement to meet pre-set
standards is not feasible.
The Department of Energy will prepare Environmental Impact Statements
or Environmental Assessment reports for each site to support the decisions
ifc will reach, with NEC's concurrence, on necessary remedial actions to
satisfy the standards. We believe that disposal methods that satisfy the
standards will avoid any ground water problems caused by future releases
from the piles for as long as the standards apply. We expect DOE to con-
sider the need for and practicality of controlling contaminants that have
already seeped into the ground under the tailings pile, and to apply techni-
cal remedies that are found justified. Institutional controls should also
be applied. If tailings are found to be contaminating ground water that is
being used, we would expect DOE to provide alternate water sources or other
appropriate remedies. We note that PL 95-604 will terminate DOE's authority
to do so as a remedial action seven years after we promulgate standards,
"nless Congress extends the period. However, Sec. 104(f)(2) of PL 95-604
Provides for Federal custody of the disposal sites under NRC licenses after
the remedial action program is completed. The custodial agency is author-
ized to carry out such monitoring, maintenance, and emergency measures as
the NRC may deem necessary to protect public health. We expect NRC's
requirements will be sufficient to ensure detection of any contamination by
the tailings of usable ground water near the disposal sites, and to cause
8-19
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the custodial agency to take such measures as may become necessary to avoid
any significant public health problem.
8.1.5 Period oj Applj.catj.on of^Disposal Standard s
Congress recognized that uranium mill tailings are hazardous for a
long time, and directed EPA to provide long-term public protection from
these hazards. We propose requiring a reasonable expectation that the
radon emission and water protection standards for disposal of tailings
piles will be satisfied for at least one thousand years.
Any choice is partly arbitrary; there are no rules or precedents to
guide the decision. Neither does scientific analysis point uniquely to one
period over another.
We have concluded that it would be impractical to apply uranium mill
tailings standards for periods as long as 10,000 years. Providing a
reasonable expectation of compliance with the standards over such long
periods, if possible at all for tailings, could be done only if they were
buried several hundred feet or more beneath the surface. During such long
time periods, climates change markedly and land surfaces may be denuded,
severely uplifted, or otherwise considerably transformed. Deep below the
surface, severe changes are likely to be more gradual and predictable. For
reasons described earlier, the practicability of deep burial of uranium
tailings is uncertain. Yet, if strict standards were to apply for as long
as 10,000 years or more, no other disposal method would seem possible.
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With tailings disposed of at or near the earth's surface it appears
feasible to meet the standards for one thousand years or more. The primary
threat during this period is flooding. Methods of protecting tailings
against floods and other natural disruptions appear to be available. These
methods, however, may not be applicable at every existing inactive site; for
long-term flood protection, for example, some piles might have to be moved.
Standards applying for less than one thousand years would be easier to
satisfy, and might result in some cost savings. The state-of-the-art of
Judging the future performance of a given disposal system does not support
naking fine distinctions, however. Therefore, the savings would be small
unless the period of application were only a few hundred years. Institu-
tional control methods such as recordkeeping, maintenance, monitoring, and
land-use restrictions are useful adjuncts to an adequate disposal system,
Providing greater protection than the standards require, and regulating
^liberate disruptions of the tailings by people.(D We do not believe,
however, that they should be relied upon for periods longer than a century,
a*d are inappropriate for long-term control. Institutional control methods
should not replace use of adequate long-term physical disposal methods.
CDpor example, Sec. 104 of PL.95-694 ^xcxpates that subsurface
minerals at a tailings disposal site might be used. It f °vlde*' ™*^er
that any tailings disturbed by such use "will be restored to a safe and
environmentally sound condition." We propose, therefore, to apply the
disposal standards to the use of any subsurface mineral rights acquired
under the provisions of Sec. 104(h).
8-21
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We believe that one thousand years meets the Congressional criterion
that "the remedial action must be done right the first time." A thousand-
year standard does not mean that our concern for the future is limited to
one thousand years; it reflects our judgment that the disposal standards
must be practical. Based on existing knowledge of control methods and
natural processes, we believe it unreasonable to generally require longer
protection under this remedial program, because adequate methods for demon-
strating compliance are not clearly available and may be very costly. We
consider it likely, however, that the implementers of the standards will
require longer protection at some piles, based on site-specific evaluations
of disposal methods and their costs.
The disposal standards could be viewed as performance standards,
stating conditions to be satisfied without addressing the means. Compliance
could be verified by monitoring, and assured through maintenance. But fun-
damentally, they are design standards. They are minimum requirements that
the designers of a disposal system should plan to satisfy over the full
period of their application. The "reasonable expectation" for meeting the
limits specified in the standards will be established by considering the
physical properties of the disposal system, not by relying on institutional
methods.
8.2 Cleanup Standards
8.2.1 Open Lands
The proposed standard requires that for any open land contaminated
with tailings, the average radium concentration in any 5-centimeter
8-22
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thickness shall not exceed 5 pCi/gm after cleanup. These conditions provide
a high degree of protection from tailings at inactive uranium processing
sites, and are not unreasonably burdensome to implement. The protection
achieved will often be greater than is apparent from the standard, since
the radium concentration of any material not removed will often decrease
sharply with depth. After the required cleanup, such a site will be little
more hazardous than a similar area which never had a tailings pile.
Locating contaminated soils with concentrations less than 5 pCi/gm
would require extensive surveys and lengthy measurement procedures. Incre-
asingly large land areas would need to be stripped in order to lower the
radioactivity much below 5 pCi/gm. Doing this would provide very little
Sain in health protection, since such slightly contaminated soils are
usually thin layers containing little total radium. To keep sampling costs
within reason, and to avoid having to clean large areas which contain little
radioactivity, the proposed final standard therefore requires that for any
°Pen land contaminated with tailings, the average radium concentration shall
n°t be more than 5 pCi/gm after cleanup. The contamination which remains
after such cleanup will have less than five times the radon release of aver-
age soils. It could also cause a gamma radiation dose of below 80 millirad
Per year to a person who spends 100% of the time outdoors on the site.
These levels of radon emission and gamma radiation are within the variations
that occur in undisturbed land areas. We believe that the actual radon and
gatnma ray levels after cleanup will usually be much less than the maximum
Possible under these standards.
8-23
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For contaminated material located more than one foot beneath the
surface of open land, our proposed standard requires cleanup if the average
radium concentration over any 15-cm thickness is greater than 5 pCi/gm.
Practical measurement instruments cannot find buried material of this
concentration in a layer any thinner. We expect that this standard for
buried material will serve mostly to define the edges of buried tailings
deposits, because the radium concentration in tailings is usually much
higher than 5 pCi/gm.
In most cases, concentrations a few times higher than the proposed
standard allows would cause only a slight increase in risk. Since concen-
tration usually declines rapidly with depth, even a standard requiring
removal of material until the radium concentration level reaches 10 or
20 pCi/gm would be protective. Unusual distributions of radium would be
much more significant, however, and areas with 5 to 20 pCi/gm are clearly
above ordinary background levels.
Surveys at inactive processing sites indicate that it should cost
little more to implement the proposed standard than one permitting levels
two to four times higher. The proposed standard is EPA's judgment of the
most stringent cleanup condition that may reasonably be required uniformly
for all the inactive mill sites.
The proposed standard addresses future as well as present hazards and
uses an intrinsic property of tailings that can be easily measured. We
considered other forms for the standard, such as limiting the residual
8-24
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surface gamma radiation, the radon release rate, or the predicted
concentration of radon decay products in future buildings on the land. All
these would restrict the residual hazard, but they would be harder to apply
to material which has been buried and might be uncovered later.
We expect that the rules developed to implement this standard will
'elate the concentration of radium in soil to other conveniently measured
quantities. We also expect that appropriate sampling techniques will be
established to locate and identify tailings material, determine its
concentration of radium, and verify compliance with the standard. Any such
rules must insure that the standard is not met simply by dispersing the
material to achieve a lower concentration.
8-2.2 Buildings
8.2.2.1 Indoor Radon Decay Product Concentration Standards
Exposure even to normal indoor radon decay product concentrations
carries some health risk, but we believe Congress intended that people
should not have to bear an unreasonable increase in this risk due to
tailings. Remedial actions will be required when a building affected by
tailings exceeds the levels we set as the remedial action standards. When
remedial actions are finished, the level must either not be exceed, or
tailings must not be the cause of any remaining excess. We believe that
expressing the indoor radon decay product standard in terms of total
concentration of these products is the only workable form, as the following
discussion indicates.
8-25
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Indoor radon decay product concentrations in normal buildings vary
widely. Tailings near or under a building may be identified by gamma ray
measurements, historical records, visual inspections, or specimen analysis.
Because of the fluctuations in normal indoor radon levels, however, it is
impossible to tell what the concentration of radon decay products would be
without the tailings. Small elevations when tailings are present cannot be
distinguished from normal background levels. Further, contaminated
buildings vary in location, design, materials, and patterns of use, all of
which affect the indoor radon decay product concentration. It is imprac-
tical to determine an expected background value for a particular building,
either from measurements of unaffected buildings or by any other means.
For these reasons, an action level expressed in terms of an increment
over the background radon decay product concentration cannot be implemented
easily. We prefer an action level in terms of the total indoor concentra-
tion, which is directly measurable. With a fixed measurement method, this
standard gives an unambiguous criterion for remedial action for any
building affected by tailings.
We also considered expressing the standard in terms of the quantity or
concentration of tailings near the building, or the gamma radiation they
produce. There is no sure way, however, to relate these quantities to
indoor radon decay product concentrations. This is a critical deficiency,
because the radon products are the basic hazard.
8-26
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A standard for total concentration of radon decay products provides
the same action level for all affected buildings, though normal concentra-
tions in one affected area may tend to be higher than in another. While
normal indoor ration decay product concentrations vary with natural radium
concentrations in soil, soil porosity, and other factors, we know of no way
to take them into account in the standard. In these circumstances, we
consider the regional protection inequity minor, as long as the action
level we choose is within the normal range of levels in the affected areas.
We believe that the proposed remedial action level of 0.015 WL
(including background) for occupied or occupiable buildings is the most
Protective level that can be justified for the PL 95-604 remedial action
Program. It is about the same as that applied to homes and schools over
the last seven years in the Grand Junction remedial action program, because
the action level there was 0.01 above an "average" background value taken
fls 0.007 WL. Experience in the Grand Junction program and studies performed
by EPA for basementless homes in Florida indicate that remedying concentra-
tions greater than 0.015 WL is usually practical in view of technical and
cost considerations. In some situations, a lower action level might be jus-
tified. However, studies of normal houses with basements in Grand Junction,
New York, and New Jersey indicate that about 10% or more are above 0.015 WL.
We have concluded that efforts to reduce levels significantly below 0.015 WL
by removing tailings would often be unfruitful, and the funds expended
wasted.
8-27
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Although indoor radon decay product levels exceeding 0.015 WL can occur
in the absence of uranium mill tailings, these proposed standards are
explicitly for remedial actions at sites designated under PL 95-604.(1)
PL 95-604 is clearly directed at potential health problems due to tailings,
and not to similar hazards from other causes. We are not calling for
lengthy and expensive procedures to determine whether any tailings are
present when the level is only slightly exceeded. Professional judgment in
the field must be relied upon in such cases to implement the standards
sensibly. If the allowable level is still exceeded after all apparent
tailings have been removed or otherwise prevented from affecting the
interior of the building, then the standard requires no further remedial
measures.
8-2.2.2 Standards for Indoor Gamma Radiation
The proposed limit on indoor radon decay product concentration is
based on the hazard from breathing air containing these products. Tailings
also emit gamma radiation, however, which can penetrate the body from the
outside. We expect that the indoor radon product concentration standards
generally will be met by removing the tailings from the buildings and that
this will eliminate any indoor gamma radiation problem. It is only in
unusual cases that a standard for limiting gamma radiation exposure may be
needed.
nonoaL *? P«ticular, the proposed remedial action standard should not
necessarily be taken as an appropriate design goal for indoor radon decay
product concentration in new housing
8-28
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It will often be possible to meet the radon decay product standards
without removing the tailings. Removal is the remedial method we wish most
to encourage, however, because of its positive and long-lasting effective-
ness. To this end, we propose an action level for gamma radiation of
0.02 mR/hr above background, (1) which allows a limited degree of
flexibility in the methods for reducing indoor radon decay product concen-
trations. On the other hand, reducing the standard much below 0.02 mR/hr
would virtually eliminate flexibility in remedial methods, and provide only
a small additional health benefit to those few individuals who might be
affected. If the occupants of the building were present 75% of the time,
the proposed standard would allow gamma radiation doses from the tailings
of about 130 mrad per year. This is about twice the average annual
background dose from gamma rays in the regions near the piles.
8.2.2.3 Radiation Hazards Not Associated with Radium-226
The total protection that a standard based on radium-226 affords
depends on the extent to which radium has been separated from other radioac-
tive substances during ore processing. Radium-226 concentrations in the
residual material may not adequately measure the radiation hazard in all
cases.
For the reasons discussed in Sec. 7.3, we cannot yet say in all cases
effective cleanup standards based on radium-226 will be in controlling
(•^Indoor background levels of gamma radiation are easier to
determine and less variable than is the case for measurements of radon
decay product concentration.
8-29
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U-235 decay products and thorium, and we are not in a position to set a
separate standard for them. It is our judgment, however, that adequate
protection would be provided if, after cleanup, the total risk from all
uranium and thorium isotopes and their decay products pose no greater risk
than the proposed final cleanup standards allow for radium-226 and its
decay products. The degree to which any particular site would need to be
cleaned in order to meet this condition will have to be determined following
detailed studies of tailings at that site, and further evaluation of the
hazard pathways there.
8-30
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References for Chapter 8
(AE 77) Atomic Energy Control Board (of Canada), April 7, 1977, "Criteria
For Radioactive Clean-up in Canada," Information Bulletin 77-2.
(CH 79) Chappel, W.R., e£ al^, 1979, "Human Health Effects of Molybdenum
in Drinking Water," USEPA Health Effects Research Laboratory
Report, EPA-600/1/79-006.
(EP 76) U.S. Environmental Protection Agency, 1976, "Quality Criteria for
Water," Report EPA-440/9-76-023.
(EP 78) U.S. Environmental Protection Agency, June 1978, "State of
Geological Knowledge Regarding Potential Transport of High-Level
Radioactive Waste from Deep Continental Repositories," Report
EPA/520/4-78-004.
(FB 76-78) Ford, Bacon, and Davis, Utah, Inc., "Phase II-Title 1,
Engineering Assessment of Inactive Uranium Mill Tailings" 20
contract reports for Depart of Energy Contract Nol
E(05-l)-1658, 1976-1978.
(FR 79) Federal Register (44 F.R. pp. 23738-23767), April 20, 1979.
(GJ 79) Grand Junction Office, February 1979, "Progress Report on the
Grand Junction Uranium Mill Tailings Remedial Action Program,"
U.S. Department of Energy Report DOE/EV-0033.
(GS 78) U.S. Geological Survey, 1978, "Geologic Disposal of High-Level
Radioactive Wastes — Earth-Science Perspectives," Circular 779.
(HE 78) Healy, J.W., and Rodgers, J.C., October 1978, "A Preliminary Study
of Radium-Contaminated Solid," Los Alamos Scientific Laboratory
Report LA-7391-MS.
(NE 78) Nelson, John D., and Shepherd, Thomas A., April 1978, "Evaluation
of Long-Term Stability of Uranium Mill Tailing Disposal
Alternatives," Civil Engineering Department, Colorado State
University, prepared for Argonne National Laboratory.
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9: IMPLEMENTATION
9.1 Administrative Process
Public Law 95-604 requires that the Secretary of Energy implement
EPA1s standards for uranium mill tailings from inactive processing sites.
The Secretary or a designated party will select and perform remedial
actions for designated processing sites in accordance with the standards,
with the full participation of any State which shares the cost. The
Nuclear Regulatory Commission (NRC) shall concur in selecting and per-
forming the remedial actions, and affected Indian tribes and the Secretary
of the Interior shall be consulted as appropriate. The Federal Government
and the States will bear the costs of the remedial actions as prescribed
fey law.
*«1.1 Disposal Standards
The disposal standards will be implemented by showing that the dispo-
sal method can reasonably be expected to satisfy the radon emmission limits
and water protection provisions of the standards for at least one thousand
years. This expectation should be founded upon analyses of the physical
Properties of the disposal system and the potential effects of natural
Processes over time. Computational models, theories, and expert judgment
will be major tools in deciding that a proposed disposal system will
satisfy the standard. Post-disposal monitoring can serve only a minor
*ole in confirming that the standards are satisfied. Where measurements
are necessary to determining compliance, they may be performed within the
accuracy of available field and laboratory instruments used in conjunction
with reasonable survey and sampling procedures.
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9.1.2 Cleanup Standards
The Department of Energy (DOE) will need to make a radiation survey of
open lands and buildings in areas believed to have tailings, and determine
whether the standards are being exceeded because of tailings. After taking
remedial action to reduce radiation, compliance with the standards will
have to be verified. DOE, working with NRC and the participating State,
will need to develop radiological survey, sampling, and measurement proce-
dures to determine necessary and practical cleanup actions, and to certify
the results of the cleanup. We have published elsewhere the general
requirements for an adequate land cleanup survey (EP 78a).
These procedures are important in making the standards effective. In
view of this, we considered providing more details of the implementation
as part of our rulemaking. To give more flexibility to the implementers,
we chose not to do so. We believe this was warranted because conditions
at the various processing sites vary widely and are incompletely known.
The following clarifies our intentions and should help to avoid the
unproductive use of resources that could result if the standards were
interpreted so strictly that complying with them would be unreasonably
burdensome.
9.1.2.1 Purpose of cleanup standards
The purpose of our standards is to protect public health and the
environment. We designed them for adequate protection using search and
verification procedures with reasonable cost and technical requirements.
Since, for example, we intend the building cleanup standards to protect
9-2
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people, measurements in such locations as crawl spaces and furnace rooms
are inappropriate.* Remedial action decisions should be based on radiation
levels in occupiable parts of the buildings. The standards for cleaning
up land surfaces are designated to limit exposures of people to gamma
radiation and to radon decay products in future buildings. In most
circumstances, failure to clean a few square feet of land contaminated by
tailings would be insignificant. Similarly, in attempting to find tailings
beneath the surface on open land, reasonableness must prevail in deter-
mining where and how deeply to search. Requiring proof that all the
tailings had been found would be unreasonable. In all applications of our
proposed cleanup standards, search and verification procedures which
provide a reasonable assurance of compliance with the standards will be
adequate. Necessary measurements may be performed within the accuracy of
available field and laboratory instruments used in conjunction with
reasonable survey and sampling procedures. We are confident that DOE and
NRC, in consultation with EPA and the States, will adopt implementation
Procedures consistent with our standards.
9»2 Exceptions
We believe that our proposed standards are the strictest that are
Justified for general application at all the inactive uranium processing
sites covered by PL 95-604. However, providing greater protection may be
reasonable at specific sites. We urge the impleraenters to lower the
residual risk as far below the required level as is reasonably achievable.
9-3
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In the decades since tailings at inactive sites were deposited,
weather and people have created a wide range of problems. The standards
may be unreasonably strict in some exceptional circumstances. If meeting
the standards is impossible, or if some clearly undesirable health or
environmental side effects are unavoidable, applying the standards would
be unjustified. Tailings may be inaccessible to the equipment needed for
their removal, or workers might be endangered in trying to remove them.
In such cases, applying the standards should be reconsidered. Similarly,
disturbing scarce desert vegetation and soils may be unjustifiable where
the standards are only slightly exceeded.
Because the scale of material-moving activity is so great, the
possibility of serious harm to both workers and the general public from
accidents associated with transporting an entire tailings pile to a new
disposal site deserves particular consideration. Relocating a pile should
be considered whenever it may be impractical to satisfy all the disposal
standards at the original location. However, circumstances might be such
that one would not expect the standards to be greatly exceeded within a
thousand years, and that substantial human exposure to any resulting
pollution would not necessarily occur. If all practical transport methods
would probably cause serious harm to people from accidents, and if this
and other risks associated with the transportation system are large
enough, the near-term danger may outweigh the additional long-term benefits
of full rather than partial compliance with the standards. By carefully
considering all these factors for each tailings pile where the issue
9-4
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arises, exceptions to the disposal standard could be justified because of
the degree of unavoidable endangerment in attempting full compliance.
We do not consider the current remoteness of a pile from population
centers sufficient by itself to justify relaxing the disposal standards.
Even small numbers of people nearby require protection, and the population
of an area could increase considerably over the one-thousand-year period
during which the standards apply. Furthermore, radon released from
tailings piles travels long distances.
We also do not consider cost a reason for noncompliance with the
standards unless the cost is very high or the benefit very small. But it
may not make sense to spend a great deal of money, for example, to clean
UP an infrequently occupied building where the standards are only slightly
exceeded.
To allow PL 95-604 to be implemented reasonably in all of the varied
circumstances, we are proposing criteria which the implementers may use to
determine whether particular circumstances are exceptional. In such excep-
tional cases, DOE may select and perform remedial actions which come as
close to meeting the standards as is reasonable. In selecting such
remedial actions, DOE shall ask any property owners and occupants for
'heir comments; the concurrence of NRC shall be required, and DOE shall
inform EPA.
9-5
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9.3 Effects of Implementing the Standards
9.3.1 Health
The proposed standards reduce average radon emissions of the tailings
piles by more than 99% for one thousand years. Extrapolating the current
rate of lung cancer deaths over that period, we estimate applying the
standards will prevent about 2,000 premature lung cancer deaths.
Some people now living very near tailings piles could bear a risk of
premature death due to lung cancer of several chances in 100. Under the
disposal standards, people living in comparable locations during the next
thousand years will bear a risk from the pile of about 1 chance in 10,000.
After remedial actions are completed on buildings eligible under
PL 95-604, their occupants will be subject to radon decay product concen-
trations of less than 0.015 WL (including background), and gamma radiation
exposure rates lower than 0.02 mR/hr. Their estimated total risk of fatal
cancer due to residual tailings following remedial action will average
less than about 1%. This is within a normal range of fluctuation for risk
from indoor radon decay products in the absence of tailings.
After remedial actions on eligible open land, residual contaminated
materials will have less than five times the radon release of average
soils. It could cause a gamma radiation dose of less than 80 millirad per
year to a person who spends 24 hours a day outdoors on the site. These
levels of radon emission and gamma radiation are within normal variations
in undisturbed land areas. We believe that the actual radon and gamma ray
9-6
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levels after cleanup will usually be much less than the maximum permitted
by these standards.
9.3.2 Envi r onment al
Since the proposed standards call for effective control for at least
°ne thousand years, dispersal by floods, erosion, or mass movement should
Qot reasonably be expected to occur during that period. Releases of radon
gas to the air from the site will be slightly above average, but within a
normal range. High-quality ground water will be protected for a wide range
°f uses, including drinking} surface waters and lower-quality ground water
will not be degraded by the tailings.
Contaminated open land will be subjected to scraping and digging by
the cleanup operations. Generally these activities will occur immediately
adjacent to the piles, but off-site areas where tailings have been deliber-
ately used also will be affected. Disposal operations may require large
Quantities of clay and soil for covering the tailings, depending on the
disposal method. The environmental effects of obtaining these materials
will vary with the site. The general ecological effects of land cleanup
and restoration operations are examined in detail in an EPA report
78b).
Q ,
Economic
Estimating the total cost of disposing of all the tailings piles
e*igibie under PL 95-604 is difficult, primarily because methods will be
chosen specifically for each site. We estimate the cost (in 1978 dollars)
9-7
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of covering an average pile to meet the proposed radon emission standard
as $1 million to $6 million if the existing site is suitable, or $6 million
to $13 million if the pile must be moved. The total disposal cost for all
sites would then be $21 million to $273 million. Deep burial and chemical
treatments could be considerably more expensive.
Cleanup costs for open land and buildings have been estimated using
interim cleanup criteria as about $10 million (see Section 7.4). Even
allowing for increased costs under the proposed standards, disposal is
still by far the largest cost component of the remedial action program.
Although difficult to estimate, the total cost of the entire program
probably will be $200 million to $300 million. The Federal government
will assume a 90% share, and any State government in which an inactive
processing
site is located will pay 10%. We expect the expenditures will be spread
over the seven-year authorization of the program. Most of these expendi-
tures will occur in the regions where the tailings are located. Their
significance depends on the amount expended, the size of the local
economy, and the availability of necessary equipment and labor.
Contaminated land and buildings might be made available for use as a
result of the cleanup program. On the other hand, moving tailings to a
new location removes the new disposal site from other potential uses.
9-8
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In summary, the program could result in net economic benefits of
decreased unemployment and increased business activity for the regions
where the piles are located. We expect little or no perceptible national
economic impact because the total seven-year expenditures will be small
compared to the annual Federal budget, (less than 0.06% of 1978 budget),
the annual Gross National Product (less than 0.01% of 1978 GNP), and the
construction industry (less than 0.5% of 1978 billings).
9-4 The Proposed Standards
The proposed standards are presented in Appendix D.
9-9
-------
References for Chapter 9
(EP 78a) "Response to Comments: Guidance on Dose Limits for Persons
Exposed to Transuranium Elements in the General Environment,
EPA Technical Report 520/4-78-010.
(EP 78b) "The Ecological Impact of Land Restoration and Cleanup,"
August 1978, EPA Technical Report 520/3-78-006.
9-10
-------
APPENDIX A
Reserved for
Comments and Responses to Comments
-------
APPENDIX B
Development of Cost Estimates
-------
APPENDIX B
Development of Cost Estimates
Page
B.1 The Average Inactive Uranium Mill Tailings Pile 1
B.2 Development of Unit Cost Computations |
B.2.1 Earth Work
B.2.2 Caps and Liners ^
B.2.3 Stabilizatibn ^
B.2.4 Fencing 13
B.2.5 Irrigation
B.2.6 Matrix Fixation 17
B.2.7 Tailings Transportation 1Q
B.2.8 Discount Rate «
B.2.9 Present Worth of Future Costs
B.2.10 Land Costs .....
B.3 Cost Estimates For Disposal Options
B.3.1 Option 1 - No Radon Control *
B.3.1.1 Option 1a - Fencing • * * * ,
B:3.1.2 Option 1b - Stabilization With No Radon Control . . 21
B.3.2 Controlling Radon Emissions with an Overburden ... «?«•
B.3.3 Option 2 - Existing Surface Site, Covered
to Control Radon Emissions 27
B.3.3.1 Dimensions 27
B.3.3.2 Cost Estimates -^
B.3.3.3 Use of Tables B-7 Through B-11 . . . • ' ' ' ' ' '
B.3.U Option 3 - New Site, Below Grade, with Liner if ^ ^
Needed * | ^5
B.3.4.1 Requirements ••••••; ' 37
B.3.M.2 Dimensions and Cost Estimates
... 39
B.4 Other Disposal Methods • • •••:,* QQ
B.4.1 Extraction and Disposal of Hazardous Materials ... |9
B.U.2 Long-Term Radon and Hydrology Control
5M
References for Appendix B
B-2
-------
FIGURE
Page
B-1 Cross-Section of the "Average" Mill Tailings Pile 5
TABLES
B-1 Unit Costs 7,8
B-2 Estimated Capital Costs for Matrix Fixation 15
B-3 Annual Operating Costs for Matrix Fixation 16
B-1 Costs and Dimensions of Particulate Control 23
B-5 Thickness (meters) of Cover Required to Reduce Radon to
Control Level 25
B-6 Control Methods for Disposal Option 2 26
B-7 Costs and Dimensions for Disposal Option 2 with Control
of Radon to 100 pCi/m2/sec 28
B-8 Costs and Dimensions for Disposal Option 2 with Control
of Radon to 10 pCi/m2/sec 29
B-9 Costs and Dimensions for Disposal Option 2 with Control
of Radon to 5 pCi/m2/sec • 30
B-10 Costs and Dimensions for Disposal Option 2 with Control
of Radon to 2 pCi/m2/sec 31
B-11 Costs and Dimensions for Disposal Option 2 with Control
of Radon to 0.5 pCi/m2/Sec 32
B-12 Control Methods for Disposal Option 3 36
B-13 Constant Costs for Below-Grade Disposal of Uranium Mill
Tailings 38
B-14 Variable Costs and Dimensions for Disposal Option 3 with
Control of Radon to 100 pCi/ra2/sec 10
B-15 Variable Costs and Dimensions for Disposal Option 3 with
Control of Radon to 10 pCi/m2/Sec 11
B-16 Variable Costs and Dimensions for Disposal Option 3 with"
Control of Radon to 5 pCi/m2/sec 12
B-17 Variable Costs and Dimensions for Disposal Option 3 with*
Control of Radon to 2 pCi/m2/sec 13
B-18 Variable Costs and Dimensions for Disposal Option 3 with"
Control of Radon to 0.5 pCi/m2/sec W
B-19 Costs of Nitric Acid Leachate Disposal ....*!.*"!*! 17
B-20 Costs of Residual Tailings Disposal . 19
B-21 Cost Estimates of Deep Disposal When a Nearby Open-pit
Mine Is Available 51
B-22 Cost Estimates of Deep Disposal When a Nearby Underground
Mine Is Available 53
B-3
-------
APPENDIX B
Development of Cost Estimates
B.1 The Average Inactive Uranium Mill Tailings Pile
To develop cost estimates of the various uranium mill tailings
disposal methods, we employed an "average" inactive uranium mill tailings
Pile, with dimensions based upon the average dimensions found at the 21
inactive uranium mill tailings sites. The tailings area, volume, and
weight dimensions have been computed from the information found in the
Ford, Bacon and Davis, Utah, Inc, engineering reports on the inactive
uranium mill tailings sites (FB 76-78).
The "average" pile has the configuration of a truncated regular pyra-
mid with a lower base of *»36m on a side, including embankments.
Figure B-1 gives a cross section of the uranium mill tailings impoundment
area. The mill tailings pile covers a surface area of a little more than
19 hectares (190,000m2, or 47 acres). The embankments contain
78M,OOOm3 (1,026,000 yd3) of uranium mill tailings, weighing
1,325,000 short tons. The tailings are assumed to be 5.0m deep within
the embankments. We further assumed that when the uranium milling
operations ceased, the tailings pile was left flat on top but uncovered,
and there is evidence of both wind and water erosion. Tests indicate
that tailings have migrated as far as 1,000m from the "average" tailings
Pile.
B-fl
-------
FIGURE B - 1
CD
tn
////////////77//////1///
CROSS-SECTION OF THE "AVERAGE" INACTIVE URANIUM MILL TAILINGS FILE
-------
B.2 Development of Unit Cost Computations
The unit costs used for estimating the costs of the disposal options
are presented in Table B-1. They are average costs and represent the
expected monetary values that will be encountered while completing indi-
vidual tasks, or purchasing specific items necessary for the various
uranium mill tailings disposal methods considered in this report. The
unit costs are in 1978 dollars and reflect the economic conditions of
that year.
The procedures used to derive the unit costs are as follows:
a. Any costs not already in 1978 dollars are adjusted
to reflect 1978 values using an appropriate price index (usually the U.S.
Department of Commerce Composite Construction Cost Index published in the
Survey of Current Business).
b. When only one source for the cost of an item is available,
that value is used.
C. When more than one cost estimate is available, the average
°f these values is used.
B»2.1 Earth Work
The sources for computing the costs for various types of earth work
Dodge (DO 78), Means (ME 77), and .the NRC-DGEIS (NR 79).
B-6
-------
TABLE B-1
Unit Costs
Task
1. Earth work
a. Below-grade excavation in normal soil
Below-grade excavation in shale
b. Dragline excavation and loading
c. Excavate, load, and haul
d. Spread and compact
e. Haul, dump, spread, and compact
2. Caps and Liners
a. Clay (when available)
b. Clay (purchase required)
c. Synthetic
d. Asphalt emulsion (1/2" thick)
3. Stabilization
a. Vegatation (when soil available)
b. Vegatation (when purchase required)
c. Riprap (.5m thick)
d. Gravel (.5m thick)
e. Chemical
4. Fencing
a. Chain-link fence 5 to 6 feet high
b. Security fence (prison grade)
5. Irrigation
a. Equipment (excluding pumps)
b. Annual operating costs
c. Submersible pump
Cost (1978 dollarsl
$1.63/ra3
$3.10/m3
$1.53/m3
$1.13/m3
$0.38/m3
$1.33/m3
$2.07'/m3
$5.00/m3
$1.76/m2
$0.75/m2
$2.51/m2
$12.90/m2
$2.57/m2
$29.69/m
$8l».51/m
$1,070/hectare
$ 273/hectare
$1,000 each
B-7
-------
TABLE B-1 (continued)
Unit Costs
Task
6. Matrix Fixation
a. Cement with thermal evaporator
Capital costs
Annual operating costs
b. Cement with filter bed
Capital costs
Annual operating costs
c. Asphalt with thermal evaporator
Capital costs
Annual operating costs
d. Asphalt with filter bed
Capital costs
Annual operating costs
7. Tailings Transportation
a. Truck
b. Rail
c. Pipeline (7" diameter)
Capital equipment and right-of-way
Operating costs
8, Discount rate (real rate of return)
9. Future Costs
a. Vegetation stabilization
Annual operating cost
Irrigation equipment
Submersible pump
b. Chemical stabilization
c. 5-6 foot chain-link fence
d. Security fence (prison grade)
10. Land Costs (farmland)
Cost (1978 dollars)
$4.75 million
$6.57 million
$6.55 million
$2.14 million
$7.90 million
$8.51 million
$9.70 million
$4.07 million
$0.10/ton-mile
$0.08/ton-mile
$63,840/mile
$0.048/ton-mile
7%
$3,900/hectare
$400/hectare
$2,500 each
$23,800/hectare
$4.27/m
$12.17/m
$781/hectare
B-8
-------
There are two types of below-grade excavation, depending on the
consistency of the material being excavated: normal or shale. Though
classified as one category, normal below-grade excavation is not
homogeneous; it includes digging in soft soil as well as in various forms
of clay. Similarly, the costs of excavating in such a variety of soil
types can vary significantly. As a result, the expected cost for normal
below-grade excavation is $1.63/m3, but may actually range anywhere
between $0.56/m3 and t5.98/m3. The average cost for below-grade
excavation of shale, on the other hand, rises to $3.10/m3, and may
range between $2.56/m3 and $3»8l/m3.
According to Ford, Bacon and Davis, Utah, Inc. (FB 76-78), a
dragline method of tailings excavation is required to remove the uranium
mill tailings from their present site. This method of tailings
excavation is assumed throughout this report. Estimates of dragline
excavation and loading establish the cost for removing the uranium mill
tailings at $1.53/m3.
Excavating, loading, and hauling surface soil up to one mile is
expected to cost $1.13/m3, but may be as low as $0.92/m3 or as high
as $1.58/m3. Spreading and compacting materials (such as mill
tailings, top soil, clay, etc.) will average $0.38/m3, but may range
between $0.22/m3 and $0.75/m3. Finally, hauling up to one mile,
dumping, spreading, and compacting is expected to cost $1.33/m3, and is
considered a single task.
B-9
-------
B.2.2 Caps and Liners
The sources for unit cost estimates of caps and liners are Dames and
Moore (DA 77), the NRC-DGEIS (NR 79), and Smith and Lambert (SM 78).
There are basically three types of caps and liners: clay, synthetic,
and asphaltic emulsion. The major purpose of a cap is to reduce radon
emissions from the mill tailings into the surface environment. A cap
also affords some hydrologic control by reducing seepage of surface water
into the tailings. Liners, on the other hand, are used chiefly to
provide hydrologic control beneath the pile. That is, a liner will
reduce moisture seepage from the mill tailings into the ground water or
ground water infiltration into the tailings.
Assuming a nearby source of suitable clay (that is, with a large
Proportion of montmorillonite) is available at no cost, a clay cap or
liner can be expected to cost $2.07/m3 to install, but may actually
range between $1.l4/m3 and $2.93/m3. If a suitable type of clay must
be purchased, an additional $2.93/m3 should be added to the cost of
installing a clay cap or liner.
Many types of synthetic materials are available which could be used
as a cap or liner for uranium mill tailings (e.g., polyester-reinforced
Hypalon or Polyvinylchloride). Because these types of caps and liner
require a carefully prepared installation, they can be quite expensive.
B-10
-------
On average, $4.i»1/m2 is the expected cost of installing a synthetic cap
or liner, but the cost may range between $2.00/m2 and $11.89/m2.
The least expensive method of providing a cap or liner for uranium
mill tailings appears to be an asphaltio emulsion. Smith and Lambert
(SM 78) estimate that the cost of applying a 0.5-ineh-thick layer of
asphaltic emulsion costs $7,140 an acre or $1.76/m2.
B.2.3 Stabilization
All methods of stabilizing uranium mill tailings disposal sites have
a common purpose; that is, to protect against wind and water erosion.
This reduces the quantity of uranium mill tailings that migrate from the
disposal site. Four methods of stabilization are considered in this
report: vegetation, riprap, gravel, and chemical.
a. Vegetation as a stabilizer consists of plants to hold
the surface in place. The proper installation of vegetation requires
approximately eight inches of suitable surface soil to insure plant
propagation. Besides seeding, fertilizer, lime, and soil binders are
also necessary to aid plant growth until a ground cover is established.
If it ts assumed that suitable top soil is available locally, the cost of
providing a vegetation cover will cost $0.75/m2, but may range between
$0.38/ra2 and $1.12/m2. If top soil and loam must be purchased, then
the cost of vegetation becomes significantly more expensive ($2.51/m2
on average, ranging between $1.U8/m2 and $3-93/ra2). These cost
estimates do not include the irrigation costs for areas without
B-11
-------
adequate precipitation. The capital and operating expenditures
associated with irrigation are discussed later.
b. Riprap consists of large stone or concrete chips (1/4 yd3
to 3/8 yd3 in size) in a layer approximately 0.5m thick as a cover on
the uranium mill tailings disposal site. Riprap is either placed loose
or enclosed in galvanized steel mesh boxes called gabions. Riprap has an
average installation cost of $12.90/m2. If placed loose, riprap can
cost as little as $4.78/m2. But if the ri-prap must be enclosed in
gabions, the cost of a riprap cover may be as high as $25.79/m2.
c. Like riprap, gravel provides wind and water erosion protec-
tion for the uranium mill tailings disposal site, and an 0.5m-thick cover
of gravel is assumed to be required for adequate wind and water erosion
protection. Installing a 0.5m-thick gravel cover costs $2.57/m2, on
average, but ranges between $2.49/m2 and $2.73/m2.
d. Other types of covers, categorized here as chemical
stabilizers, include asphalt, asphaltic emulsion, road oil, and various
other chemicals. Although the chemical stabilizers appear to be the
least expensive method of stabilizing a uranium mill tailings disposal
site (the average installation cost is $0.75/m2), the application cost
ranges widely, between $0.05/m2 and $9.69/m2. Further, their
long-term stability is untested. Some methods require replacement in
less than a year while others may last 20 years or more. For cost
B-12
-------
estimates, we assumed that a chemical stabilizer will need replacement
every four years.
B.2.4 Fencing
Sources for unit costs of fencing are Dodge (DO 78), Means (ME 77),
the NRC-DGEIS (NR 79), and Smith and Lambert (SM 78).
Isolation of the uranium mill tailings disposal site from intrusion
can be accomplished by a fencfc. We considered two types of fences in
this report. A chain-link fence five to six feet high, with or without
several strands of barbed wire on top, costs an average of $29.69/m to
install, but may range between $21.33/m ?nd $49.21/ra. If more security
is required, a prison-grade security fence 12 to 16 feet high will cost
$84.51/m to install, but may be as low as $73.49/m or as high as
$95.5U/m. These costs include installation, corner posts, and a gate.
The effective life of these fences is assumed to be one hundred years,
with proper maintenance. Annual maintenance for the fences is expected
to be cost 1? of the original expenditure for the fences.
B.2.5 Irrigation
The capital and annual operating expenditures for irrigation used in
this report have been taken from the NRC-DGEIS (NR 79). All costs are
stated on a per hectare basis, except for submersible pumps. Annual
operating expenditures for running and maintaining irrigation equipment
are expected to be $273 per year per hectare. This value includes
B-13
-------
fertilizer, power, operating labor, maintenance on the irrigation equip-
ment, and ground water analyses. Installation of the irrigation
equipment, including pumps and miscellaneous valves and nozzles, will
cost $1,070 per hectare. It is expected that this equipment will need
replacement an average of every 20 years. In addition, one submersible
pump, at a cost of $1,000 is required for every 20 hectares irrigated.
Replacement of the submersible pumps can be expected every five years.
B.2.6 Matrix Fixation
Uranium mill tailings could be incorporated into a concrete or
asphalt mixture, reducing the leachability of the tailings into the
hydrologic system. A detailed discussion of the methods and require-
ments for fixing uranium mill tailings in a concrete or asphalt matrix
oan be found in the NRC-DGEIS (NR 79).
Detailed breakdowns of the estimated capital expenditures and annual
operation costs for the various methods of matrix fixation are given in
Tables B-2 and B-3. These tables have been taken directly from the
NRC-DGEIS (NR 79), Tables 11.9 and 11.10, respectively.
From a cost standpoint, significant savings can be realized in
initial capital costs and in annual operating expenditures if a cement
rather than asphalt matrix is used. In addition, the metho'd of drying
the tailings before incorporation into either a cement or asphalt matrix
has significant cost implications. For both concrete and asphalt
-------
TABLE B-2
Estimated Capital Costs for Matrix Fixation3^
(thousands of 1978 dollars)
Thermal Evaporator Filter ^
Equipment Cement Asphalt Cement Asphalt
Sand washing and drying $ 230 $ 230 $ 230 $ 230
Lime neutralization 670 670 670 670
Slimes filtration (vacuum disc
filter) 1,150 1,150
Tailings dewatering bed — 2 120 2 120
Evaporators 1,470 1,1470
ii»ajju{-c»i/j.oii pona
Asphalt fixation
Cement fixation
TOTAL
___
1,210
$4.750
--—
M.UOO
^$7,900
2,300
1,210
$6.550
2,300
MOO
$9.700
(a)NRC-DGEIS (NR 79), Table 11.9.
B-15
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TABLE B-3
(a)
Annual Operating Costs for Matrix Fixation'
(thousands of 1978 dollars)
Costs
Salaries
Maintenance
Power
Fuel
Asphalt
Cement
TOTAL (annual)
Thermal Evaporator
Cement Asphalt
$ 170
110
75
4,250
1,970
$6,575
$ 170
170
75
14,7^0
3,360
...
$8,515
Filter Bed
Cement
$ 85
50
35
—
1,970
$2,1 HO
Asphalt
$ 85
100
35
490
3,360
—
$4 , 070
(a)NRC-DGEIS (NR 79), Table 11.10.
B-16
-------
fixation, initial capital costs are somewhat less expensive for
mechanically drying the tailings with a thermal evaporator than with a
"dewatering filter bed" (a sand filter). Significant savings in annual
operating expenditures can be gained, however, by using the "dewatering
filter bed" rather than the thermal evaporator. That is, annual
operating costs are at least a factor of two less than those for a
thermal evaporator for both cement and asphalt matrix fixation.
B.2.7 Tailings Transportation
We considered three methods of hauling uranium mill tailings:
truck, rail, and slurry pipeline. According to Ford, Bacon and Davis,
Utah, Inc. (FB 76-78), contract haulers can transport mill tailings at a
cost of $0.10/ton-mile. For longer distances of 50 miles or more, rail
transport, at $0.08/ton-mile, offers some cost advantages over trucking.
Unless the tailings pile is located at a rail head, however, the tailings
will have to be hauled to the rail line by truck.
Transporting uranium mill tailings by pipeline offers greatly
reduced operating expenditures as compared to either truck or rail, but
requires heavy initial capital and right-of-way costs. According to
Dames and Moore (DA 77), a pipeline 7" in diameter costs $63,8HO/mile to
construct and to reserve the right-of-way. Transporting mill tailings
via such a pipeline is estimated to cost $O.OM8/ton-mile.
B-17
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B.2.8 Discount Rate
The discount rate is assumed to be 7%. This is the estimated
average real rate of return considering all elements of society (NR 76).
The real rate of return is the current rate of return minus the inflation
rate. The discount rate is used for computing the present discounted
value of future costs (to maintain and replace fences in the future, for
example).
B.2.9 Present Worth of Future Costs
Several control methods may require perpetual care or periodic
replacement in order to maintain the intended level of effectiveness.
For example, we assumed that chemical stabilization needs replacement
every four years. Fences are assumed to require annual maintenance, and
replacement every hundred years. Finally, natural precipitation may need
to be supplemented with irrigation to maintain a proper vegetation cover
for surface stabilization. The irrigation system is assumed to require
annual maintenance, and periodic replacement.
The present worth of all future costs are included in the cost
breakdown shown in the tables where appropriate. The formula used for
Present worth calculations is:
where: PW • present worth,
C = replacement cost of the item considered, or
its periodic maintenance cost,
n = the useful life of the item, or the
periodic maintenance period,
i » the annual discount rate.
B-18
-------
This formula assumes that maintenance and replacement continues
indefinitely. The annual discount rate used in all calculations is !%•
B.2.10 Land Costs
Smith and Lambert (SM 78) estimate that farmland costs an average of
$781 per hectare, and may range between $160 and $5,189 per hectare.
B-3 Cost Estimates For Disposal Options
Using the estimated unit costs (from Table B-1) and assuming the
dimensions of the average inactive uranium mill tailings pile, we have
estimated costs for the tasks necessary to complete various disposal
options. When considered as various combinations of the tasks, the
estimated costs offer numerous control options. In actual practice, the
choice of a specific disposal option and actual control cost will depend
on such site-specific parameters as the radon emission rate, size, and
condition of the specific mill tailings pile.
B.3.1 Option 1 - No Radon Control
This option may be implemented either by constructing a fence around
the existing disposal site (thereby restricting access) or by stabilizing
the existing mill tailings pile to reduce future wind and water erosion.
B.3.1.1 Option 1a - Fencing
In this disposal option, the uranium mill tailings pile is left at
its existing surface location and a fence is erected around the site. No
B-19
-------
control of radon-222 releases, particulate releases, or ground water
impacts is provided, although fencing provides some control of direct
gamma radiation by preventing people from living near the tailings pile.
It is assumed that wind erosion can cause particulates to migrate as far
as 1000m from the pile. Therefore, it is assumed that a 1000m
exclusionary zone is required on all sides of the tailings pile.
The cost of a fence can be expected to range between $290,000 for a
chain-link fence five to six feet high and $820,000 for a security fence
of prison grade. The present worth of annual maintenance and replacement
every hundred years is estimated to be $40,000 for a chain link fence and
$120,000 for a security fence.
In either case, the fence encloses 593-4 hectares of land. The
tailings pile is assumed to be on a 19-hectare site that is already
publicly owned. It is assumed that the remaining 511.1 hectares must be
purchased, at a cost of $130,000. The 19 hectares already under public
ownership represent a cost to society, since they are unavailable for
alternative uses. The best alternative use is assumed to be
agricultural. The "opportunity cost," or market value, of the land is an
estimated $10,000. In total, the cost of the "no control" option is
*790,000 if a chain-link fence five to six feet high is used, and $2.1
million if a security fence is employed.
B-20
-------
B.3-1.2 Option 1b - Stabilization With No Radon Control
The mill tailings pile is left in place in this disposal option but
stabilized to prevent wind and water erosion. Several of the existing
inactive tailings piles have already been stabilized with about six inches
of soil cover, vegetation, gravel, or riprap. The equivalent of 0.5m of
riprap cover is required to ensure longevity. A 15cm to 0.5m dike cover
would meet short-term requirements, but vould be subject to both wind and
water erosion and thus subsequent degradation. Riprap cover has been
utilized at one pile and experience with stabilization of large tailings
piles is quite limited. This level of control might be accomplished
through the use of chemical sprays, which either form a surface crust or
bind the surface tailings into a crust. Experience with such methods,
however, indicates that the resulting crusts are not resistant to
environmental degradation (Tuba City and Salt Lake City (FB 76)). The
degradation results from intrusion by man and animals, ultraviolet
radiation, and various climatological effects. Chemical sprays and
binders appear to require a protective layer of dirt or riprap to assure
even a relatively short lifetime of 10 years. Thus, they have a limited
applicability for this level of control.
The sides of the tailings pile must be shaped to a slope ratio of
8:1 to minimize future erosion and a 20m exclusionary zone should be
provided around the pile. Besides a chain-link fence and a security
fence, several stabilization methods are considered here. Vegetation
could be employed, but may require the purchase of suitable top soil or
B-21
-------
an irrigation system. Potentially, riprap and gravel could provide
long-term wind and water erosion protection. Finally, chemical
stabilizers provide erosion protection but are expected to need
replacement every four years.
Table B-4 presents the cost and dimension estimates for the
alternative methods that will control particulates at the model uranium
mill tailings pile.
At a minimum, the total cost of providing wind and water erosion
protection for the model mill tailings pile will be $500,000. This
includes: enough earthwork to change the embankment slopes from 2:1 to
8:1, stabilization by vegetation that requires neither soil purchase or
irrigation, and a chain-link fence five to six feet high. On the other
hand, the level of control could cost as much as $3-6 million if the
model pile roust be stabilized by riprap and isolated by a security fence,
B-22
-------
TABLE B-4
Costs and Dimensions of Participate Control
Volume of earth work (m3) 135 000
Area of cover (ra2) 2*47*000
Length of fence (m) 2*140
Area within fence (ra2) 287*000
------------------ Costs (in thousands of 1978 dollars) ---- ~ ___ - ______
Earth work 200
Stabilization
Veg: With no need to
purchase soil 18Q
With purchase of soil 620
Irrigation
(labor & equip.) H0
Riprap ^ 1flo
,
Chemical
Fencing
Chain-link, five to six feet high 60
Security (prison grade)
Future Costs
Irrigation
(labor & equip.) 110
Chemical stabilization cqo
Chain- link fence w
Security fence 50
Value of Land 20
B-23
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B.3.2 Controlling Radon Emissions with an Overburden
As noted in the NRC-DGEIS (NR 79), radon emanation can be reduced by
appropriately thick overburden. The overburden may be a layer of soil or
a combination of soil and a cap consisting of asphalt, clay, or synthetic
material. For Option 2 (Existing Surface Site, Covered to Control Radon)
and Option 3 (New Site, Below Grade, with Liner if Needed), seven types
of overburden are considered for dimension and cost estimation. The
required thickness of overburden needed to provide the five selected
radon attenuation levels for each type of overburden are presented in
Table B-5.
B.3.3. Option 2 - Existing Surface Site.
Covered to Control Radon Emissions
This disposal option consits of covering the tailings pile at the
existing surface site for control of radon-222 releases. In addition,
this control option reduces wind and water erosion of the mill tailings,
attenuates gamma radiation, and provides some control of ground water
contamination. Basically, this option requires three steps: covering
the mill tailings, stabilizing the pile against wind and water erosion,
and fencing the disposal area to prevent intrusion. There are several
ways to accomplish each steps. This leads to numerous possible
combinations of methods to implement this disposal option. The steps and
their alternative methods are given in Table B-6.
-------
TABLE B-5
Thickness (meters) of Cover Required to Reduce Radon to Control Level
2
Radon Control Level (pCi/rc /sec)
100 10 5 2 0,5
Soil(a) 1.1 2.9 3.4 U.1 5.1
Soil + 0.6 m Clay(b) o.3 0.9 1.M 2.1 3.2
Soil + 1.0 m Clay(c) 0.3 0.7 0.8 1.0 1.9
Soil + Asphalt(d) .. __ .. ._ 0.5
Soil + Synthetic(d) __ __ __ __ 0.5
with average radon-attenuating properties.
(b)Thickness includes both clay and soil. If thickness is 0.6m or less
then includes clay only.
(c)Thickness includes both clay and soil. If thickness is 1.0m or less
then includes clay only.
(d)Asphalt and synthetic caps are assumed to reduce radon to at least
1.0 pCi/m2 sec. Thickness only includes soil. The dashes (—)
mean no soil is required.
Source: NHC-DGEIS, Table K-6.1, p.K-27. (Ref. NR 79)
B-25
-------
TABLE B-6
Control Methods for Disposal Option 2
(Existing Surface Site, Covered to Control Radon)
1 • Cover
a. Soil (normal radon-attenuation properties)
b. Soil + 0.6m clay (no clay purchase required)
c. Soil + 0.6m clay (clay purchase required)
d. Soil + 1.0m clay (no clay purchase required)
e. Soil + 1.0m clay (clay purchase required)
f. Soil + asphalt
g. Soil + synthetic
2. Stabilization
a. Vegetation (no soil or loam purchase required)
b. Vegetation (soil or loam purchase required)
c. Irrigation required (a or b)
d. Irrigation not required (a or b)
e. Riprap
f. Gravel
P. Chemical
3. Fence
a. Chain-link fence five to six feet high
b. Security fence (prison grade)
B-26
-------
B.3.3.1 Dimensions
All dimensions assume that the existing uranium mill tailings piles
and the resultant 'disposal mounds are in the shape of truncated regular
pyramids. By assumption, the sides of the final disposal mound have a
slope ratio of 8:1 in order to resist future wind and water erosion.
Also, an exclusionary zone of 20m from the base of the final disposal
mound is assumed. Finally, the dimensions and conditions of the average
inactive uranium mill tailings pile are those described in Section B.1.
B.3.3.2 Cost Estimates
Cost estimates based on the dimensions of the average inactive
uranium mill tailings pile are presented for each of five selected radon
attenuation levels in Tables B-7 through B-11. Cost estimates for
various tasks necessary to implement Option 2 are found in these tables.
Note that the total cost of implementing Option 2 will vary with such
things as the desired radon attenuation level, the selected type of
overburden, the method of stabilization, and the fencing.
Several points concerning the derivation of the cost estimates need
some explanation:
1. The volume of earth work, specific to a type of cover, does not
include the volume of the cap. With clay caps, for example, the volume
of the cap is not included in the volume of the earth work.
B-27
-------
TABLE B-7
Costs and Dimensions for Disposal
2
Option 2 with Control of Radon to 100 pCi/m /sec
Depth of cover (m)
Volume of cover (m3)
Area of cover (m2)
Length of fence (m)
Area within fence (m2)
f t
Costs (in
Earth work
Cap
Clay
With clay available
With clay purchase
Other
Asphalt
Synthetic
Stabilization
Veg: NO need to
purchase soil
With purchase of soil
Irrigation
(labor & equip.)
Riprap
Gravel
Chemical
Fencing
Chain link, five to six
feet high
Security (prison grade)
Future Costs
Irrigation
(labor & equip.)
Chemical stabilization
Chain-link fence
8ftf«iv4 *w £*nr*a
Soil
1.1
415,000
264,000
2,210
306,000
thousands of
$ 630
-
—
"
200
660
40
3,410
680
200
70
190
120
630
10
30
Soil +
.6m Clay
.3
209,000
251,000
2,160
292,000
.
1 Q TSt ft /\1 1 0 V* B 1 •
iy/O QOLLaL&J
$ 240
110
260
™*
190
630
i t\
40
3,240
650
190
60
180
110
600
10
30
Soil +
1m Clay
.3
209,000
251,000
2,160
292,000
$ 240
110
260
190
630
3,240
650
* A/\
190
60
180
110
600
10
30
Soil +
Other
-
•»
«•
•••••••••»••»•••••
-
-
I
-
_
-
••
-
Value of land
20
20
20
B-28
-------
TABLE B-8
Costs and Dimensions for Disposal
Depth of cover (m)
Volume of cover (m3)
Aera of cover (m2)
Length of fence (m)
Area within fence (m2)
Soil
2.9
917,000
295,000
2,330
339,000
Soil +
.6m Clay
.9
363,000
261,000
2,200
303,000
Soil +
1m Clay
.7
311,000
258,000
2,190
299,000
+
Other_
-
••
••
—
. Costs (in thousands of 1978 dollars)
Earthwork $1,380 $390 $290
Cap
Clay
With clay available - 210 250
With purchase of clay - 520 610
Other
Asphalt -
Synthetic -
Stabilization
Veg: No need to
purchase soil 220 200 190
With purchase of soil 740 660 650
Irrigation
(labor & equip.) 40 40 40
Riprap 3,810 3,370 3,330
Gravel 760 670 660
Chemical 220 190 190
Fencing
Chain link 70 70 70
Security (prison grade) 200 190 190
Future Costs
Irrigation
(labor & equip.) 130 120 120
Chemical stabilization 700 620 610
Chain-link fence 10 10 10
Security fence 30 30 30
Value of Land 30 20 20
B-29
-------
TABLE B-9
Costs and Dimensions for Disposal
-* • -
Depth of cover (m)
Volume of cover (m3) 1
Area of cover (m2)
Length of fence (m)
Area within fence (m2)
_ / •
Cost (in
Earth Work
Cap
Clay
With clay available
With clay purchase
Other
Asphalt
Synthetic
Stabilization
Veg: No need to
purchase soil
With purchase of soil
Irrigation
(labor & equip.)
Riprap
Gravel
Chemical
Fencing
Chain link
Security (prison grade)
Future Costs
Irrigation
(labor & equip.)
Chemical stablization
Chain- link fence
QAS«««W« ^« £A-V*J*A
Soil
3.4
,066,000
304,000
2,360
349,000
thousands
$1,610
—
•
230
760
40
3,920
780
220
70
200
140
720
1 A
1U
30
Soil +
,6m Clay
1.4
495,000
269,000
2,230
312,000
_r i mQ «i«O 1 a*-a ^—
or J.7/O dollars/
$ 590
210
520
200
680
40
3,480
690
200
70
190
120
640
10
A v
30
+ .
1m Clay
.8
337,000
260,000
2,200
301,000
$ 300
290
690
190
650
40
3,350
670
190
70
190
120
620
10
30
Soil +
Other
-
•*•
•^^•^•M^-W
—
—
_m
—
• »
-
-
-
Value of Land
B-30
30 20 20
-------
TABLE B-10
Costs and Dimensions for Disposal
2
Option 2 with Control of Radon to 2 pCi/m /sec
Depth of cover (m)
Volume of cover (m3)
Area of cover (m2)
Length of fence (m)
Area within fence (m2)
Soil
4.1
1,283,000
317,000
2,410
362,000
Soil +
.6m Clay
2.1
687,000
281,000
2,280
324,000
Soil + Soil +
1m Clay Other
1.0
389.000
263,000
2,210
305,000
Costs (in thousands of 1978 dollars)
Earth Work $1,940 $ 880 $ 330
Cap
Clay
With clay available - 210 360
With clay purchase - 520 870
Other
Asphalt -
Synthetic -
Stabilization
Veg: No need to
purchase soil 240 210 200
With purchase of soil 790 710 660
Irrigation
(labor & equip.) 40 40 40
Riprap 4,080 3,630 3,390
Gravel 810 720 680
Chemical 230 210 190
Fencing
Chain link 70 70 70
Security (prison grade) 200 190 190
Future Costs
Irrigation
(labor & equip.) 140 130 120
Chemical stabilization 750 670 630
Chain-link fence 10 10 10
Security fence 30 30 30
Value of Land 30 20 20
B-31
-------
TABLE B-ll
Costs and Dimensions for Disposal
2
Option 2 with Control of Radon to 0.5 pCi/m /sec
Depth' of cover (m)
Volume of cover (m3) 1,
Area of cover (m2)
Length of fence (m)
Area within fence (m2)
Earth Work
Cap
Clay
With clay available
With clay purchase
Other
Asphalt
Synthetic
Stabilization
Veg: No need to
purchase soil
With purchase of soil
Irrigation
(labor & equip.)
Riprap
Gravel
Chemical
Fencing
Chain link
Security (prison grade)
Future Costs
Irrigation
(labor & equip.)
Chemical stabilization
Chain- link fence
Security fence
Soil
5.1
607,000
335,000
2,470
381,000
Soil +
.6m Clay
3.2
1,006,000
300,000
2,350
345,000
(in thousands of 1978
$2,430
-
-
-
••
250
840
50
4,320
860
250
70
210
150
800
10
30
$1,360
210
520
-
™
230
750
40
3,880
770
220
70
200
130
720
10
30
Soil +
1m Clay
1.9
631,000
278,000
2,270
321,000
$ 690
360
870
-
"
210
700
40
3,590
710
200
70
190
120
660
10
30
Soil +
Other
.5
260,000
255,000
2,180
296,000
$ 390
—
mm
300
760
190
640
40
3,290
650
190
60
180
110
610
10
30
Value of Land 30 30 30 20
B-32
-------
2. Earth work includes excavating, loading, hauling up to one mile,
spreading, and compacting surface soil.
3. Caps are assumed to cover both the tailings and the crest of the
impoundment dikes.
U. Asphalt and synthetic caps are expected to reduce radon releases
to 1.0 pCi/m2/sec without additional soil cover. As a result, cost
estimates for covers involving asphalt or synthetic caps have been
computed only for radon control levels of 1.0 pCi/m2/sec and below.
5. Several control methods in Table B-6 require periodic mainten-
ance and replacement of equipment (e.g., irrigation equipment, chemical
stabilizers, and fences). The discounted present value of these future
costs have been computed in each case.
6. After control measures are completed, the use of land within the
fences will presumably be restricted. Alternative uses, such as
agricultural, therefore will be permanently denied. This opportunity cost
should be considered in the decision-making process along with the other
costs. For this purpose, the restricted land is assumed to have
agricultural uses, and the opportunity cost is equal to the market value
of the property.
B-33
-------
B.3.3.3 Use of Tables B-7 Through B-11
Since Tables B-7 through B-11 present only the costs of accomplishing
particular tasks that might be employed in a control option, it is
important for the reader to understand the proper use of these tables for
deriving the total cost for a desired control option.
After selecting the desired radon attenuation level and type of/
overburden (i.e., reading down one column of the selected table) one can
calculate a total cost for the selected control option.d) The total
cost is then equal to the sum of the cost of the required overburden
(earth work plus cap costs), the cost of the specific method of
stabilization (plus the cost of irrigation if required), the cost of the
desired fence, the necessary future costs, and the market value of the
land. For example, the total cost of attenuating to a radon flux equal
to 5 PCi/m2/seo (refer to Table B-9) is $1.2 million, if soil plus a
1.0ro clay cap is used as an overburden (assuming a suitable clay is
locally available at no cost). We assumed that the site is stabilized
with vegetation requiring both the purchase of top soil and irrigation
equipment, and that a chain-link fence five to six feet high is required.
the asphalt or synthetic caps differ
B-31*
-------
B'3*1* Option 3 - New Site. Below Grade, with Liner if Needed
The objective of Option 3 is not only to reduce radon emission and
gamma radiation, but also to provide greater hydrologic control than
Option 2 would afford.
B.3.4.1 Requirements
In addition to the three steps necessary to implement Option 2, this
option requires excavating a special pit, installing a liner (if neces-
sary), and transporting the tailings to the pit site. The need for a
liner depends on the subsoil characteristics at the new site. If the
subsoil is relatively impervious to moisture seepage (e.g., clay with a
high montmorillonite content, or impervious shale), then a special liner
may not be required. Also, a pit above the water table may obviate the
need for a liner. For this option, transporting the tailings includes
excavating the tailings from their present site, hauling them to the new
site, and depositing the mill tailings in the pit.
Like Option 2, there are several ways of accomplishing each step of
this option. Table B-12 presents each step and alternatives.
Considering each possible combination presented in Table B-12 leads to
numerous methods of implementing this disposal option.
B-35
-------
TABLE B-12
Control Methods for Disposal Option 3
(New Site, Below Grade, with Liner if Needed)
1. Tailings Transportation
a. Truck
b. Truck and rail
c. Pipeline
2. Below-Grade Excavation
a. Normal
b. Shale (ripping necessary)
3. Liner
a. Clay (with clay available)
b. Clay (clay purchase required)
c. Asphalt
d. Synthetic
e. None
4. Cover
a. Soil (normal radon-attenuation properties)
b. Soil + 0.6m clay (with clay available)
c. Soil + 0.6m clay (clay purchase required)
d. Soil + 1.0m clay (with clay available)
e. Soil + 1.0m clay (clay purchase required)
f. Soil + asphalt
g. Soil + synthetic
5« Stabilization
a. Vegetation (no soil or loam purchase required)
b. Vegetation (soil or loam purchase required)
c. Irrigation required (a or b)
d. Irrigation not required (a or b)
e Riprap
f. Gravel
g. Chemical
6» Fence
a. Chain-link fence five to six feet high
b. Security fence (prison grade)
B-36
-------
B.3.^.2 Dimensions and Cost Estimates
For each of five selected radon attentuation levels, we calculated
dimensions and costs for the various control methods for implementing
Option 3 (Table B-12). The distance to the new disposal site and the
geometric configuration of the pit are assumed constant in this analysis.
Several of the dimensions (and, therefore, the costs) also remain constant
regardless of the depth and type of overburden placed over the mill
tailings, while other dimensions (and costs) vary. These constant costs
are given in Table B-13.
As previously noted, there are 78U,OOOm3 of uranium mill tailings
(weighing 1,325,000 short tons) to be excavated by dragline and hauled to
the pit site. The area to be stabilized is 1?6,000m2 (the pit,
regardless of depth, is assumed to a square K2Qm on a side). Similarly,
1,8UOra of fencing will be required to enclose 212,000m2 of land
(including both trie pit and the exclusionary zone which is 20m on each
side). The excavated pit is assumed to be in the shape of a truncated
inverted regular pyramid whose sides are required to have a slope.ratio
of 3:1.
We assumed that the pit site is located 10 miles from the inactive
mill tailings site. Rail heads are assumed to be situated one mile from
both the inactive tailings site and the pit site. It is assumed that the
land for the pit and its exclusion zone will be purchased at the market
B-37
-------
TABLE B- 13
Constant Costs for Below-Grade Disposal of Uranium Mill Tailings
In thousands of 1978 dollars
Excavate, load, spread, and compact tailings $1,500
Tailings Transportation
Truck 1,300
Truck and rail 1»100
Pipline 1»280
Stabilization
Veg: No soil purchase 130
With soil purchase W°
Irrigation
(labor and equip.) 30
Riprap 2»280
Gravel
Chemical
Fencing
Chain link 5°
Security (prison grade) 1^°
Land Cost 20
Future costs
Irrigation (labor and equip.) 10°
Chemical stabilization 509
Chain-link fence ™
Security fence 20
B-38
-------
value of farmland. For this disposal option "earth work" means
below-grade excavation, hauling up to one mile, dumping, spreading, and
compacting subsoil, and disposing of any excavated subsoil not used in the
cover. The costs that vary by radon control level are given in Tables
B-11) through B-18 for each selected level.
B.l» Other Disposal Methods
There are several high-cost alternatives to the disposal methods
previously considered. These methods are discussed in the NRC-DGEIS
(NR 79). Two of these methods are considered here: burial in a strip-
mine or underground mine, and nitric acid leching for the removal of
hazardous materials. Potentially, these alternatives offer considerable
radon attenuation (below 0.5 pCi/m2/sec), but the long-term
environmental impact of these methods has not been tested.
B'1*'1 Extraction and Disposal of Hazardous Materials
Technology has not been developed for extracting radium or
nonradiological toxic elements from the tailings, because until now there
has been no need for this method
A nitric acid leaching plant could be set up to remove the radium and
thorium in the tailings. Tailings from this process would still require
some treatment, though the radioactivity level would be considerably
lower. Some hazardous nonradiological elements would remain. Seepage
from the new pile would contain nitrates instead of the sulfates found in
B-39
-------
TABLE B-14
Variable Costs and Dimensions for Disposal
p
Option 3 with Control of Radon to 100 pCi/m /sec
Depth of cover (m)
Vol. of pit
With clay liner (m3)
No clay liner (m3)
Vol. of clay liner (m3)
Area for other liner (ra2)
Vol. of clay cap (m3)
Area for other cap (m2)
Soil
1.1
1,145,000
975,000
170,000
172,000
—
—
Soil +
,6m Clay
.3
1,014,000
837,000
177,000
176,000
53,000
— '
Soil + Soil +
Ira Clay Other
.3
1,014,000
837,000
177,000
176,000
53 , 000
"
-Costs (in thousands of 1978 dollars)-
Earth work
No clay liner
Normal digging $2,890 $2,480 $2,480
Shale 4,320 3,710 3,710
Clay liner nnn
Normal digging 3,390 3,000 3,000
Shale 5,100 4,490 4,490
Liner
C1Clay available 350 370 370
With clay purchase 850 890 890
Other
Asphalt 300 310 310
Synthetic 760 780 780
Cap
With clay available -
With clay purchase -
Other
Asphalt
Synthetic "
B-40
-------
TABLE B-15
Variable Costs and Dimensions for Disposal
Option 3 with Control of Radon to 10 pCi/tn2/sec
Depth of cover (m)
Vol. of pit
With clay liner (m3)
No clay liner (m3)
Vol. of clay liner (m3)
Area for other liner (m2)
Vol. of clay cap (m3)
Area for other cap (m2)
Soil
2.9
1,436,000
1,275,000
162,000
163,000
—
—
Soil +
.6m Clay
.9
1 , 1 1 1 , 000
941,000
170,000
173,000
104,000
-
Soil + Soil +
1tn Clay Other
.7
1,078,000
906,000
172,000
174,000
122,000
— —
•Costs (in thousands of 1978 dollars)-
Earth work
No clay liner
Normal digging $3,770 $2,790 $2,680
Shale 5,650 4,170 4,020
Clay liner
Normal digging 4,250 3,290 3,190
Shale 6,360 4,920 4,780
Liner
Clay
With clay available 330 350 360
With clay purchase 810 850 860
Other
Asphalt 290 300 310
Synthetic 720 770 770
Cap
Clay
With clay available - 220 250
With clay purchase - 520 610
Other
Asphalt -
Synthetic - -
B-41
-------
TABLE B-16
Variable Costs and Dimensions for Disposal
Depth of cover (m)
Vol. of pit
With clay liner (ra3)
With no liner (m3)
Vol. of clay liner (m3)
Area for other liner (ra2)
Vol. of clay cap (ra3)
Area for other cap (ra2)
Soil
3.4
1,514,000
1,355,000.
158,000
161,000
-
•
Soil +
.6m Clay
1.4
1,195,000
1,026,000
168,000
171,000
103,000
™*
Soil +
1m Clay
.8
1,095,000
924,000
172,000
174,000
140,000
Soil +
Othei
• _ -
-
-
-
—
-
-Costs (in thousands of 1978 dollars)-
Earth work
No clay liner
Liner
With clay available 330 350 360
With clay purchase 790 840 860
73;°
770
Synthetic 710
Cap
With clay available - 210 290
With clay purchase . - DIU
Other
Asphalt "'
Synthetic
B-42
-------
TABLE B-17
Variable Costs and Dimensions for Disposal
p
Option 3 with Control of Radon to 2 pCi/m /seo
Depth of cover (m)
Vol. of pit
With clay liner (m3)
No clay liner (m3)
Vol. of clay liner (m3)
Area for other liner (m2)
Vol. of clay cap (m3)
Area for other cap (m2)
Soil
4.1
1,621,000
1,468,000
155,000
158,000
-
-
Soil +
.6m Clay
2.1
1,308,000
1,144,000
165,000
167,000
100,000
Mi
________________________Pna^n (in thmi«anrt« of* 1Q7R
Earth work
No clay liner
Normal digging
Shale
Clay liner
Normal digging
Shale
Liner
Clay
With clay available
With clay purchase
Other
Asphalt
Synthetic
Cap
Clay
With clay available
With clay purchase
$4,340
6,490
4,800
7,180
320
780
280
700
-
-
$3,390
5,070
3,870
5,800
340
820
290
740
210
500
Soil +
1m Clay
1.0
1,128,000
958,000
170,000
173,000
174,000
-
$2,840
4,240
3,340
5,000
350
850
300
760
360
870
Soil +
Other
_
-
-
-
-
-
~
-
-
-
-
_
-
—
-
—
-
Other
Asphalt
Synthetic
-------
TABLE B-18
Variable Costs and Dimensions for Disposal
2
Option 3 with Control of Radon to 0.5 pCi/m /sec
Soil + Soil +
Depth of cover (m)
Vol. of pit
With clay liner (m3) 1
No clay liner (m3) 1
Vol. of clay liner (m3)
Area for other liner (m2)
Vol. of clay cap (m3)
Area of other cap (m2)
Earth work
No clay liner
Normal digging
Shale
Clay liner
Normal digging
Shale
Liner
Clay
With clay available
With clay purchase
Other
Asphalt
Synthetic
Cap
Clay
«f
With clay available
With clay purchase
Other
Asphalt
Soil
5.1
,771,000
,620,000
151,000
153,000
_
-
/ •! M tVl/\1YQ9'
V In T*nOU3cl
$4,800
7,180
5,240
7, .850
310
760
270
670
_
^
.6m Clay 1m
3.2 1
1,482,000 1,277
1,323,000 1,110
159,000 166
162,000 168
97,000 169
—
nrt«» nf 1Q78 dollars)
IIUO UA ' 7 ' V* W A. * W4 U /
$3,920
5,860
4,390
6,570
330
760
290
710
200
490
~ .
Clay
.9
,000
,000
,000
,000
,000
—
$3,290
4,920
3,780
5,660
340
830
300
740
350
850
_
Soil +
Other
.5
1,045,000
872,000
173,000
175,000
-
174,000
$2,580
3,860
3,090
4,630
360
870
310
780
-
310
770
Synthetic
B-44
-------
a conventional mill tailings. Nitrates are quite mobile if seepage
reaches ground water. The cost of chemical treatment of tailings is as
yet undetermined, but could be expected to be as expensive as the original
milling process, excluding ore grinding. Since this technique is expected
to be only about 90$ effective, some action would still be required to
isolate the tailings from the biosphere and to dispose of the extracted
material in a licensed waste burial site.
Uranium mill tailings disposal by a nitric acid leaching process
requires construction and operation of a nitric acid leaching mill,
disposal of the concentrated nitric acid leachate, and disposal of the
residual tailings. The construction and operation of a nitric acid
leaching mill is quite expensive. The NRC-DGEIS (NR 79) estimates that a
model nitric acid leaching mill costs $35 million to construct and an
additional $37.7 million to equip (1978 dollars), while operating costs
are expected to run $12.50 per ton of processed uranium mill tailings.
Assuming that the model inactive mill pile contains 1.32 million
short tons of tailings and that a model nitric acid leaching mill can
process 1,984 short tons of mill tailings and produce 55 short tons of
nitric acid leachate per day, then 668 days of operation would be required
to process the mill tailings. In .addition, approximately 37,000 short
tons of nitric acid leachate will be generated. Consequently, the total
operating cost for a model nitric acid leaching mill at the model inactive
mill tailings pile is expected to run $16.6 million. Some of the
construction materials used in a model nitric acid leaching mill might be
-------
employed at more than one inactive mill tailings site, or might have.some
scrap value. These possibilities are not analyzed here, due to the
uncertainties of apportioning construction costs and determining future
scrap values. We therefore assume that each inactive mill tiilings site
requires building a new nitric acid leaching mill at a cost of $35
million. On the other hand, we assume that the nitric acid leaching
equipment can be used at more than one inactive mill tailings site. As a
result, cost of the nitric acid leaching equipment is equal to its
depreciated value. Assuming two years of use at the model inactive mill
tailings site, a 15-year life expectancy for the nitric acid leaching
equipment, and straight-line depreciation, the expected cost of the nitric
acid leaching equipment is $5 million at each model inactive mill tailings
site. An additional $5 million is added to cover the costs of transport-
ation between different mill tailings sites, set-up and take-down costs,
and extra wear and tear on the equipment, as well as other contingencies.
We therefore exp.ect the total nitric acid leaching equipment costs to be
$10 million. In total, we expect nitric acid leaching to cost $61.6
million (1978 dollars) to construct, equip, and operate the model inactive
mill tailings site.
When combined in an asphalt or cement matrix, the nitric acid
leachate matrix has a volume of 17,100m3 and requires a cover 10m thick.
for proper disposal. The disposal of the nitric acid leachate would
require a pit 13.% deep and covering an area of .5 hectares (100m by
50m). The possible costs of disposing of the nitric acid leachate are
Presented in Table B-19.
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TABLE B-19
Costs of Nitric Acid Leachate Disposal
(thousands of 1978 dollars)
Task Cost
Earth work
Normal digging $200
Shale 300
Fixation
Asphalt 560
Cement 380
Stabilization
Vegetation
No need to purchase soil 14
With soil purchase 30
Irrigation 2
Riprap 60
Gravel 10
Chemical 4
Fencing(a)
Chain link !0
Security (prison grade) fence 40
Future costs
Irrigation 10
Chemical stabilization 30
Chain link fence 2
Security (prison grade) fence 10
Value of land 1
^)Includes a 20m isolation zone around the disposal pit.
-------
The NRC-DGEIS (NR 79) estimates that the concentration of radium
remaining in the residual tailings after nitric acid leaching is at least
an order of magnitude greater than background levels. If soil with
average radon attenuation properties is available in the area, a
3.8m=thick cover will provide attenuation to 0.1 pCi/m2=sec. Assuming
that the nitric acid leaching process insignificantly alters the quantity
of residual tailings, and using the assumptions employed for Option 3
(Section B.3.4 — New Site, Below Grade, with Liner if Needed), then the
disposal costs for the residual tailings can be computed. The costs of
disposing of the residual tailings are presented in Table B-20.
In summary, nitric acid leaching of the tailings for the model
inactive mill site will cost $61.6 million. Under the best conditions,
disposal of the nitric acid leachate can be expected to cost an additional
$600,000 (normal soil excavation, stabilization with vegetation—no
irrigation required—and isolation with a chain-link fence). Under the
worst conditions, disposing of the nitric acid leachate will cost
*970,000 (shale excavation, riprap stabilization and security fence
isolation). Disposal costs for the residual tailings will be $7 million
at best—that is, if no liner is required; excavation is in normal soil;
tailings are transported by truck and rail; vegetation requiring no
irrigation is used to stabilize the disposal site; and the disposal site
is isolated with a chain-link fence. On the other hand, the costs of
disposing of the residual tailings could be as high as $13.1 million if a
clay liner is used and the clay must be purchased; pit excavation is in
shale, trucks are the only transportation available for the tailings; and
the disposal site is stabilized by riprap and isolated bv a security
B-48
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" 1LE B-20
Costs of Residual Tailings Disposal
(thousands of 1978 dollars)
Task Cost
Earth work
Clay liner not required
Normal digging $M,200
Shale 6,290
Liner
Clay
With clay available 320
With clay purchase 780
Asphalt 280
Synthetic 700
None
Tailings excavation, loading,
spreading and compacting 1,500
Tailings transportation
Truck 1,300
Truck and rail 1,100
Pipeline 1,270
Stabilization
Vegetation
No need to purchase soil 130
With soil purchase 4MO
Irrigation equipment 30
Riprap 2,280
Gravel H50
Chemical 130
Fencing
Chain link 50
Security (prison grade) 160
Future Costs
Irrigation equipment 100
Chemical stabilization 500
Chain-link fence 10
Security (prison grade) fence 20
Value of land 20
B-U9
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fence. As a result, the cost of uranium mill tailings disposal at the
model inactive mill site, using a nitric acid leaching process, could be
expected to range between $69.2 and $75.7 million.
B.4.2 Long-Term Radon and Hydrology Control
It is unreasonable to expect that the uranium mill tailings can be
completely isolated at the existing sites. The concept of complete
long-term isolation (of both radon and ground water) essentially requires
special site selection and emplacement techniques. The NEC DGEIS (NR 79)
describes two methods that conceivably will meet these criteria: deep
disposal in an open-pit mine and deep disposal in an underground mine.
In the case of an open-pit mine, the mill tailings may be loosely
deposited in the pit but enclosed in a watertight liner and cap, or they
can be combined with asphalt or cement to prevent leaching into the
surface and ground water environment. Table B-21 presents cost estimates
which assume an available open-pit coal mine or copper quarry within 10
miles. Long-term radon and hydrology control could cost as little as $6.9
million. This includes only expenses for dragline excavation of the
tailings, truck and rail tailings transport, and loose tailings disposal
with an asphalt liner and cap. These cost estimates are relatively low
B-50
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TABLE B-21
Cost Estimates for Deep Disposal
When a Nearby Open-Pit Mine Is Available
(thousands in 1978 dollars)
Task
Evacuate & load tailings
Tailings transportation
Truck
Truck & rail
Pipeline
Tailings disposal
Loose with liner & cap
Cement fixation
Thermal evaporator
Filter bed
Asphalt fixation
Thermal evaporator
Filter bed
Disposal of mine contents
Vegetation cover
No need to purchase soil
Soil purchase required
Cost
$1,200
1,330
1,100
1,300
£1,600
17,900
10,830
24,930
17,840
28,130
690
4,600
B-51
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because it is assumed that there is an operating open-pit mine close to
the mill tailings pile, and that the mine owners are willing to cover the
mill tailings at no cost as part of their post-operation reclamation of
the mine site. On the other hand, costs could increase to $57.5 million,
if the mill tailings are deposited in an abandoned open pit mine,
transported by truck, dried by a thermal evaporator, and incorporated into
an asphalt matrix. It is also assumed that the disposal site is
stabilized with vegetation, requiring the purchase of suitable top soil.
Unlike the previous control levels, however, there is no long-term
commitment to institutional maintenance and the site will be available for
alternative future u,ses.
In another approach, it is assumed that a nearby abandoned
underground mine is available. In this case, it is assumed that the
tailings will need to be fixed in an asphalt or cement matrix to prevent
leaching. Further, holes will be bored into the mine cavities for
depositing the asphalt or cement matrix. Cost estimates for deep disposal
of the mill tailings in an underground mine are presented in Table B-22.
Implementing this method of tailings disposal would cost from $13.1
million to $27.5 million.
B-52
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TABLE B-22
Cost Estimates of Deep Disposal
When a Nearby Underground Mine Is Available
(thousands in 1978 dollars)
Task
Evacuate & load tailings
Tailings transportation
Truck
Truck & rail
Pipeline
Bore holes
Tailings disposal
Cement fixation
Thermal evaporator
Filter bed
Asphalt fixation
Thermal evaporator
Filter bed
Cost
$1,200
1,330
1,100
1,300
20
17,900
10,830
24,930
17,840
B-53
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References for Appendix B
(DA 77) Dames & Moore, 1977, "An Evaluation of the Cost Parameters
for
Hypothetical Uranium Milling Operations and Ore
Transportation Systems in the Western United States,"
Argonne National Laboratory, Job No. 10263-001-07.
(DO 78) Dodge Building Cost Services, 1978, 1978 Dodge Guide for
Estimating Public Works Construction Costs. McGraw-Hill: New
York, N.Y.
(FB 76-78) Ford, Bacon and Davis Utah, Inc., "Phase II-Title 1,
Engineering Assessment of Inactive Uranium Mill Tailings,"
?0 reports for Department of Energy Contract No.
. E(05-D-1*58, 1976-1978.
(ME 77) Means, Robert Snow, 1977, Building Construction Cost Data
1977. Robert Snow Means, Co., Inc.: Duxbury, Mass.
(NR 76) U.S. Nuclear Regulatory Commission, August 1976, "Final
Generic Environmental Statement on the Use of Recycled
Plutonium in Mixed Oxide Fuel in Light Water Cooled
Reactors," NUREG-0002, Vol. H.
(NR 79) U.S. Nuclear Regulatory Commission, April 1979, "Generic
Environmental Impact Statement on Uranium Milling,"
NUREG-0511.
(SM 78) Smith, C. Bruce and Lambert, Janet A., June 1978,
"Technology and Costs for Cleaning Up Land Contaminated with
Plutonium," in "Selected Topics: Transuranium Elements in
the General Environment," U.S. Environmental Protection
Agency, ORP/CSD-78-1.
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APPENDIX-C
Toxicologies of Toxic Substances in Tailings
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APPENDIX C: Toxicologies of Toxic-Substances in-Tail ings
The toxicologies of the following substances found in tailings are
summarized:
arsenic nitrate
barium radium
cadmium selenium
chromium silver
lead thorium
mercury uranium
molybdenum
C.I Arsenic
Arsenic is a metal apparently not essential to human nutrition. It
is widely distributed in nature and used estensively in medicine and
agriculture. The pentavalent form is less toxic than the trivalent
(23 milligrams of arsenic taken as arsenic trioxide has been fatal
(JO 63)), but usually more teratogenic(l) (VE 78).
Chronic poisoning produces skin abnormalities, proteinuria, anemia,
and swelling of the liver. Some cardiac and nervous symptoms have been
associated in Japan with drinking well water containing 1 to 3 parts per
(1)Teratogenicity is the capability to cause abnormal fetal development.
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million of arsenic (TE 60). Epidemiologic studies of chronic arsenic
poisoning in Antofagasta, Chile, found a high incidence of skin and
cardiovascular abnormalities; chronic coryza and abdominal pain, and some
chronic diarrhea in children who drank water containing 600 to 800 parts
per billion of arsenic (NA 77). The incidence of skin lesions decreased by
a factor of about 16 when the arsenic content of the water was decreased to
80 parts per billion (NA 77), but the effects did not disappear completely.
Chronic consumption of arsenic has also been linked with increased
incidence of lung cancer (VE 78) and skin cancer (VE 78, NA 77, GO 77).
C.2 Barium
Barium is a metal apparently not essential to human nutrition. It is
widely distributed in nature and used in industry, medicine, and
agriculture. Consumption of 550 to 600 milligrams of barium as barium
chloride has been reported to be fatal (SO 57).
Ingested barium causes abnormal muscle stimulation due to induced
release of catacholamines from the adrenal medulla. There is, however, no
evidence of chronic toxicity from long-term consumption of barium in people
or animals (NA 77, UN 77).
C.3 Cadmium
Cadmium is a metal distributed in the environment in trace quantities
except in some zinc, copper and other ores. It is not essential to human
C-2
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nutrition. It is used in industry. Acute fatal poisoning with cadmium is
difficult because cadmium salts cause vomiting when consumed. Acute
poisoning from consuming food or drink contaminated with cadmium occurs 15
to 30 minutes after 15 to 30 milligrams of cadmium has been swallowed
(EN 79). Symptoms include continuous vomiting, salivation, choking sensa-
tions, abdominal pain, and diarrhea. Acute toxicity symptoms have been
reported in school children eating popsicles containing 13 to 15 milligrams
of cadmium per liter (EN 76).
Absorbed cadmium is toxic to all body organs, damaging cells and
enzyme systems. Little is excreted, so it accumulates over the lifetime.
In Japan, where people consumed about 0.6 milligrams of cadmium per day,
chronic toxicity was reported (EN 76). The illness was called "Itai-itai"
disease, and resulted in bone and kidney damage. Symptoms were seen mostly
in older women whose diets were very poor, especially lacking in protein
and calcium (UN 77, NA 77). Since cadmium toxicity is moderated by
calcium, zinc, copper and maganese (UN 77) and selenium, iron, vitamin C,
and protein (GO 77), diet is important.
The earliest symptom of chronic cadmium toxicity is kidney damage,
evidenced by increased protein in the urine. This occurs when the cadmium
level in the renal cortex reaches 200 to 300 micrograms per gram of wet
weight (EN 76, EN 79). This 200-microgram level can be reached after
consuming about 350 micrograms of cadmium a day for 50 years (EN 76).
Consumption of only 60 micrograms a day has been estimated to cause kidney
C-3
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damage in 1% of the exposed group (EN 79). The body retains as much
cadmium from smoking one pack of cigarettes per day as from ingesting 25
micrograms of cadmium a day (EN 79).
Cadmium has caused reproductive disturbances and teratogenesis in
experimental animals fed high levels (VE 78, UN 77, EN 79, NA 77). It has
also been implicated in human hypertension, cardiac problems, and prostatic
carcinogenesis (UN 77, EN 79, GO 77, NA 77), but the connection is not
definitive.
C.4 Chromium
Chromium is a metal that is essential to human nutrition; it is
involved in glucose and lipid metabolism and protein synthesis (UN 77). It
is widely distributed in nature and has many industrial applications. Oral
toxicity is low; humans can tolerate 500 milligrams daily of chromic
sesquioxide (VE 78). Hexavalent chromium is more toxic than trivalent
(UN 77, VE 78). The principle damage in acute chromium poisoning is
tubular necrosis in the kidney. Large enough doses of hexavalent chromium
can cause gastrointestinal tract hemorrhaging, but lifetime exposure of
laboratory animals to less than 5 parts per million of chromium in drinking
water caused no reported effects (NA 77, UN 77).
No information exists on the effects of chronic consumption in humans.
C-4
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C.5 Lead
Lead is a metal widely distributed in nature and used extensively in
industry and agriculture; it is not essential to human nutrition. The
amount of lead absorbed before symptoms of toxicity appear is rarely known;
however, one man ingested 3.2 milligrams per day for two years before
symptoms occurred (NA 72).
Toxicity is usually related to levels of lead in the blood. A level
of 330 micrograms per 100 grams of blood has been associated with acute
brain pathology and death in children (NA 72). Levels of 80 micrograms per
100 grams of blood and greater have been associated with brain, nervous
system, and kidney pathology; severe colic; seizures; paralysis; blindness,
and ataxia in children (NA 72, GO 77, NA 77, UN 77). Subclinical (hard to
detect because clinical symptoms are lacking) effects on the central
nervous system, the red blood cells, the kidneys, and enzymes may occur at
levels of 40 to 80 micrograms of lead per 100 grams of blood (GO 77). In
women and children some changes in red cells can be detected at 25 to 30
micrograms per 100 grams of blood (NA 77).
Drinking water containing 100 micrograms of lead per liter results in
blood lead levels of 25 to 40 micrograms per 100 grams of blood, (UN 77,
NA 77). Such exposure could lead to some clinical lead poisoning,
particularly in children (NA 77).
C-5
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C.6 Mercury
Mercury is a metal not essential to human nutrition. It is distributed
in nature as a trace element except in some metal ores, and has many indus-
trial applications. Consumption of 158 milligrams of mercury as mercuric
iodide has been reported fatal (VE 78). Effects of nonfatal doses of
mercury salts include local irritation, coagulation, and necrosis of tissue,
kidney damage, colitis, hallucinations, and a metallic taste in the mouth.
As with lead, chronic mercury poisoning develops slowly. Many of the
symptoms relate to the nervous system: impaired walking, speech, hearing,
vision, or chewing; insomnia; anxiety; mental disturbances; and ataxia.
There also may be damage to kidneys, blood cells, gastrointestinal tract,
and enzyme systems (NA 77, VE 78). Studies of Minamata disease (methyl
mercury poisoning) suggest that consumption of one milligram of mercury per
day as methyl mercury over a period of several weeks will be fatal (VE 78);
consumption of 0.3 milligrams per day will cause clinical symptoms of
mercury poisoning (UN 77, NA 77). About 10 times as much methyl mercury
would be absorbed as inorganic mercury (GO 77).
Mercury passes through the placenta. It has caused cases of Minamata
disease by fetal exposure (NA 77), and may cause birth defects (VE 78,
UN 77).
C-6
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C.7 Molybdenum
Molybdenum is a metal essential in trace quantities for human
nutrition. It is present in nature in trace quantities, except in some
ores. It has been widely used in industry. There are no data for acute
toxicity of molybdenum in humans following ingestion, but the animal data
(VE 78) shows that it must be in the range of hundreds of milligrams per
kilogram of body weight.
Chronic toxicity has been seen in persons who have consumed 10 to 15
milligrams of molybdenum per day (CH 79). Clinical signs of the toxicity
were a high incidence of a gout-like disease and increased urinary
excretion of copper and uric acid. Increased urinary copper excretion has
been observed in persons who consumed 0.5 to 1.5 milligrams of molybdenum
per day, and in persons who drank water containing 0.15 to 0.20 milligrams
of molybdenum per liter, but not in persons who drank water containing up
to 0.05 milligrams of molybdenum per liter (CH 79). The significance of
the increased copper excretion is not known.
C.8 Nitrate
Nitrate, a salt of nitric acid, is the stable form of combined
nitrogen in oxygenated water, and all nitrogenous materials in natural
waters tend to be converted to nitrate (NA 77). The fatal dose has been
estimated as 120 to 600 milligrams of nitrate (27 to 136 milligrams of
nitrate-nitrogen) per kilogram of body weight (BU 61). Burden estimated
the maximum permissible dose of nitrate-nitrogen as 12 milligrams in a
C-7
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three-kilogram infant and 240 milligrams in a 60-kilogram adult (BU 61).
Apparently nitrate is converted to nitrite in the gastrointestinal tract,
and the absorbed nitrite causes the toxicity (NA 72a, NA 77).
Chronic toxicity is usually observed in children. Symptoms of
toxicity have been reported in children drinking water with 11 milligrams
or more of nitrate-nitrogen per liter, but not in those consuming nine
milligrams or less per liter (NA 72a, NA 77).
Nitrates can be reduced to nitrites and combined with secondary amines
or amides to form N-nitroso compounds, which are considered carcinogens
(NA 72a, NA 77).
C.9 Radium
Radium is a metal widely distributed in the environment in trace
quantitities except in some ores. It is not essential to human nutrition.
In the past it was widely used in industry and medicine. No reliable data
exist on acute radium toxicity in humans (SI 45) and chemical toxicity, if
any, is expected to be masked by radiation damage (VE 78).
Chronic intake of radium is expected to be carcinogenic, especially in
bone. Radium isotopes are expected to have roughly the same chronic
toxicity per unit of activity (picocurie) consumed, but not per unit of
weight (microgram) consumed (IN 79). Radium-227, which is one thousand to
C-8
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ten thousand times less toxic than other radium isotopes (IN 79), may be an
exception.
Consuming one picocurie of radium per day continuously entails a risk
of developing cancer of about one in 10 million per year (EN 76).
C.10 Selenium
Selenium, a metal, is widely but unevenly distributed in nature. It
is essential in human nutrition in trace amounts (NA 77). It is used in
industry and medicine.
Drinking water containing nine milligrams of selenium per liter for'a
three month period caused development of symptoms of selenium toxicity:
listlessness, loss of hair, and loss of mental alertness (EN 76). Other
symptoms of selenium toxicity include garlicky breath, depression, derma-
titis, nervousness, gastrointestinal disturbance, and skin discoloration
(EN 76, NA 77). Consumption of one milligram per kilogram of body weight
per day may cause chronic selenium poisoning (GO 77). Bad teeth, gastro-
intestinal disturbances and skin discoloration have been associated with
consumption of 0.01 to 0.1 milligram of selenium per kilogram of body
weight per day (EN 76).
Selenium has also been suggested to cause increased teratogenesis and
dental caries, but there are little data on these questions (VE 78).
C-9
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C.ll Silver
Silver is a metal distributed in trace levels in the environment
except in some ores. It is not essential to human nutrition. It is widely
used in industry, medicine, photography, and art. Data on acute toxicity
in people are sparse, but consumption of 140 milligrams of silver nitrate
causes severe gastroenteritis, diarrhea, spasms, and paralysis leading to
death (VE 78).
Chronic toxicity from soluble silver salts is usually associated with
argyria, a permanent blue-grey discoloration of the skin caused by
deposited silver (EN 76, NA 77). Silver deposited in tissue, especially in
the skin, apparently is retained there indefinitely (EN 76), perhaps as a
harmless silver-protein complex, or as silver sulfide or selenide (VE 78).
If one gram of accumulated silver causes borderline argyria, as postulated
by the National Academy of Sciences, this level would be reached after 50
years of drinking water containing 50 micrograms of silver per liter, or
after 91 years at 30 micrograms per liter (NA 77). Prolonged consumption
of silver salts may also cause liver and kidney damage and changes in blood
cells (VE 78).
C.12 Thorium
Thorium is a metal distributed in the environment in trace quantities,
except in some ores. It is not essential to human nutrition. It is used
in industry and as a nuclear power source. It was formly used in medicine.
C-10
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There are no data on toxicity in humans. In animal studies, thorium
given orally at levels near one gram per kilogram of body weight causes
death in half of the animals (VE 78).
Chronic toxicity appears limited to carcinogenesis associated with the
radioactivity of the thorium. The various isotopes of thorium are expected
to vary greatly in toxicity, considered on a per-unit-activity basis
(IN 79); all are expected to produce radiation-related cancers.
C.13 Uranium
Uranium is a metal widely distributed in the environment in trace
quantities. It is not essential to human nutrition. It is used in the
nuclear power industry.
Acute toxicity in humans has been estimated to occur, based on kidney
damage, following absorption of 0.1 milligram per kilogram of body weight?
some deaths would be expected following absorption of one milligram per
kilogram of body weight (LU 58). If 20% of the uranium in water is
absorbed, this would be equivalent to 17.5 milligrams and 175 milligrams
per liter of uranium, respectively, for a 70-kilogram man. Oral doses of
10.8 milligrams of uranium (as uranyl nitrate hexahydrate) apparently
caused no kidney damage (HU 69). However, consumption of 470 milligrams of
uranium (one gram of uranyl nitrate) caused vomiting, diarrhea, and some
albuminuria (BU 55).
C-ll
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Building up a tolerance to uranium is apparently possible. Spoor
cites reports from the medical literature of the 1890's where uranyl
nitrate was used to treat diabetes, starting with a conditioning dose of
about 60 milligrams of uranyl nitrate three times a day after meals and
gradually raising the dose to six grains of uranyl nitrate a day (SP 68).
If such doses were given without conditioning, they would be expected to be
fatal.
Chronic toxicity may also be related to enzyme poisoning in the
kidneys (LU 58), with some liver damage as a result of the kidney damage
(VE 78). Experiments with animals which inhaled uranium compounds for a
year showed mild kidney changes associated with about one microgram of
uranium per gram of kidney. Extending these results to a human kidney
weight of 300 grams, absorption of 20% of uranium in water and deposition
of 11% of absorbed uranium in the kidney retained with a 15-day half-life
(SP 73) could cause chronic chemical toxicity in humans who drink water
containing about 315 micrograms of uranium per liter.
Uranium can also cause chronic toxicity in the form of radiation-
related carcinogenesis. The various uranium isotopes vary greatly in their
carcinogenic potentials as considered on a unit activity basis (IN 79).
There is some question as to whether radiation-related cancer or chemical
toxicit will be the major response to some uranium isotopes.
C-12
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References- for Appendix- C
(BU 55) Butterworth, A. The Significance and Value of Uranium in Urine
Analysis, Trans. Ass. Indstr. Med. Offrs. 5_:36-43 (1955).
(BU 61) Burden, E.H.W.J. The Toxicology of Nitrates and Nitrites with
Particular Reference to the Potability of Water Supplies. Analyst
86:429-433 (1961).
(CH 79) Chappell, W.R., et al -. , "Human Health Effects of Molybdemum in
Drinking Water^HTSlPA", Health Effects Research Laboratory,
EPA-600/1-79-006, 1979.
(EN 76) Environmental Protection Agency. National Interim-Primary
Drinking- Water Regulations , EPA-570/9-76-003. USEPA, Ottice of
Water Supply, Washington, D.C., 1976.
(EN 79) Environmental Protection Agency. Cadmium- Ambient Water Quality
Criteria. Office of Water Planning and Standards, USEPA,
Washington, D.C., 1979.
(GO 77) Goyer, R.A. and Mehlman, M.A. editors, Toxicology of • Trace
Elements, Advances in Modern Toxicology, Vol. 2. John wney &
Sons, New York, 1977.
(HU 69) Hursh, J.B., e£ al^, Oral Ingestion of Uranium by Man, Health
Physics 11:619-621 (1969).
(IN 79) International Commission on Radiological Protection, Limits for
Intakes of Radionuelides by Workers, ICRP Publications 30,
Pergamon Press, New York, 1979.
(JO 63) Johnstone, R.M. , "Metabolic Inhibitors 2" (1963), cited by
Underwood, E.J., (see UN 77).
(LU 58) Luessenhop, J., et aK, The Toxicity in Man of Hexavalent Uranium
Following Intravenous Administration, Amer. J. Roentgenol.
72:83-100 (1958).
(NA 72) National Academy of Sciences, Lead: -Airborne- Lead in Perspective-,
NAS-NRC, Washington, D.C., 1972.
(NA 72a) National Academy of Sciences, Accumulation- of -Nitrate, Committee
on Nitrate Accumulation, NAS-NRC, Washington, i*/z,
(NA 77) National Academy of Sciences, Drinking Water and- Health^ Part^^
Chapters- 1-5, NAS Advisory Center on Toxicology, Assembly of Life
Sciences, Washington, 1977.
C-13
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(SI 45) Silberstein, H.E., Radium Poisoning, AECD-2122, USAEC Technical
Information Division, Oak Ridge, 1945.
(SO 57) Sollman, T., A Manual of Pharmacology, 8th edition, W.B. Saunders
Co., Philadelphia, 1957.
(SP 68) Spoor, N.L., Occupational Hygiene-Standards-for Natural Uranium,
AHSB(RP)77. Radiological Protection Division, UKAEA, Harwell,
1968.
(SP 73) Spoor N.L. and Hursh, J.B., Protection Criteria, pp. 241-270 in
Uranium-Plutonium-Transplutonic Elements, B.C. Hodge, J.N.
Stannard and J.B. Hursh, editors, Springer-Verlag, New York, 1973.
(TE 60) Terada, H., et al., Clinical Observations of Chronic Toxicosis by
Arsenic, Ninon Tlnsho, 18:2394-2403, (1960), (EPA translation No.
TR 106-74).
(UN 77) Underwood, E.J., Trace•Elements in-Human-and•Animal•Nutrition,
Fourth Edition, Academic Press, New York, 1977.
(VE 78) Venugopal, B. and Luckey, T.D., Metal Toxicity in Mammals .2,
Chemical Toxicity of Metals and-Metaloids. Plenum Press, New York,
1978.
C-14
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APPENDIX D
The Proposed Standards
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The Administrator of the Environmental Protection Agency hereby
proposes to add a Part 192 to Title 40 of the Code of Federal Regulations
as follows:
Part 192 - ENVIRONMENTAL PROTECTION STANDARDS FOR
URANIUM MILL TAILINGS
Subpart A — Environmental Standards for the Disposal of Residual
Radioactive Materials from Inactive Uranium Processing Sites
192.01 Applicability
192.02 Definitions
192.03 Standards
192.04 Effective date
Subpart B - Environmental Standards for Cleanup of
Open Lands and Buildings Contaminated with Residual
Radioactive Materials from Inactive Uranium Processing Sites
192.10 Applicability
192.11 Definitions
192.12 Standards
192.13 Effective date
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Subpart C — Exceptions
192.20 Criteria for exceptions
192.21 Remedial actions for exceptional circumstances
(Authority: Section 275 of the Atomic Energy Act of 1954, 42 U.S.C. 2022,
as amended by the Uranium Mill Tailings Radiation Control Act of 1978,
PL 95-604.)
Subpart A — Environmental Standards for Disposal of Residual
Radioactive Materials from Inactive Uranium Processing Sites
192.01 Applicability
This subpart applies to the disposal of residual radioactive material
at any designated processing site or depository site as part of any
remedial action conducted under Title I of the Uranium Mill Tailings
Radiation Control Act of 1978 (PL 95-604), or following any use of sub-
surface minerals at such a site.
192.02 Definitions
(a) Unless otherwise indicated in this subpart, all terms shall have
the same meaning as in Title I of the Uranium Mill Tailings Radiation
Control Act of 1978 and the Atomic Energy Act.
(b) Remedial action means any action performed under Section 108 of
the Uranium Mill Tailings Radiation Control Act of 1978.
(c) Disposal means any remedial action intended to assure the
long-term, safe, and environmentally sound stabilization of residual
radioactive materials.
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(d) Disposal site means the region within the smallest practical
boundaries around residual radioactive material following completion of
disposal.
(e) Depository site means a disposal site selected under Section
104(b) or 105(b) of the Uranium Mill Tailings Radiation Control Act of
1978.
(f) Aquifer means a geologic formation, group of formations, or
portion of a formation capable of yielding usable quantities of ground
water to wells or springs.
(g) Ground water means water below the land surface in the zone of
saturation.
(h) Underground source of drinking water means:
(1) an aquifer supplying drinking water for human consumption, or
(2) an aquifer in which the ground water contains less than
10,000 milligrams/liter total dissolved solids.
(i) Curie (Ci) means the amount of radioactive material which
produces 37 billion nuclear transformations per second. One picocurie
(pCi) - 10-12 ci.
(j) Surface waters means "waters of the United States, including the
territorial seas" ("navigable waters") ap defined in the Federal Register,
Volume 44, page 32901, June 7, 1979. (Comment; This definition is taken
from the Regulations for the National Pollutant Discharge Elimination
System, 40 CPR 122.3(t). In essence, it includes all U.S. surface waters
which the public may traverse, enter, or draw food from.)
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192.03 Standards
Disposal of residual radioactive materials shall be conducted in a
way that provides a reasonable expectation that for at least one thousand
years following disposal —
(a) The average annual release of radon-222 from a disposal site
to the atmosphere by residual radioactive materials will not exceed
2 pCi/m2-8ec.*
(b) Substances released from residual radioactive materials
after disposal will not cause
(1) the concentration of that substance in any underground
source of drinking water to exceed the level specified in Table A, or
(2) an increase in the concentration of that substance in
any underground source of drinking water, where the concentration of that
substance prior to remedial action exceeds the level specified in Table A
for causes other than residual radioactive materials.
This subsection shall apply to the dissolved portion of any
substance listed in Table A at any distance greater than 1.0 kilometer
from a disposal site that is part of an inactive processing site, or
greater than 0.1 kilometer if the disposal site is a depository site.
* NOTj-! Ths radon emitted from a tailings site after disposal will come
from the tailings and from materials covering them. Radon emissions from
the covering materials should be estimated as part of developing a
disposal plan for each site. These plans will be reviewed and concurred
with by the Nuclear Regulatory Commission prior to disposal. After
disposal, the radon emission standard is satisfied if the emission rate is
less than or equal to 2 pCi/m2-8ec plus the emission rate expected from
the disposal materials.
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(c) Substances released from the disposal site after disposal
will not cause the concentration of any harmful dissolved substance in any
surface waters to increase above the level that would otherwise prevail.
192.04 Effective date
The standards of this Subpart shall be effective 60 days after final
promulgation of this rule.
Subpart B — Environmental Standards for Cleanup
of Open Lands and Buildings Contaminated with Residual
Radioactive Materials from Inactive Uranium Processing Sites
192.10 Applicability
This subpart applies to open lands and buildings which are part of any
processing site designated by the Secretary of Energy under PL 95-604,
Section 102. Section 101 of PL 95-604, states that "processing site"
means —
i
(A) any site, including the mill, containing residual radioactive
materials at which all or substantially all of the uranium was produced
for sale to any Federal agency prior to January 1, 1971 under a contract
with any Federal agency, except in the case of a site at or near Slick
Rock, Colorado, unless —
(i) such site was owned or controlled as of January 1, 1978, or is
thereafter owned or controlled, by any Federal agency, or
(ii) a license (issued by the (Nuclear Regulatory) Commission or
its predecessor agency under the Atomic Energy Act of 1954 or by a
State as permitted under section 274 of such Act) for the production
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at such site of any uranium or thorium product derived from ores is in
effect on January 1, 1978, or is issued or renewed after such date;
and
(B) any other real property or improvement thereon which —
(i) is in the vicinity of such site, and
(ii) is determined by the Secretary, in consultation with the
Commission, to be contaminated with residual radioactive materials
derived from such site.
Any ownership or control of an area by a Federal agency which is acquired
pursuant to a cooperative agreement under this title shall not be treated
as ownership or control by such agency for purposes of subparagraph (A)(i).
A license for the production of any uranium product from residual radioac-
tive materials shall not be treated as a license for production from ores
within the meaning of subparagraph (A)(ii) if such production is in
accordance with section 108(b).
192.11 Definitions
(a) Unless otherwise indicated in this subpart, all terms shall have
the same meaning as defined in Title I of the Uranium Mill Tailings
Radiation Control Act of 1978.
(b) Remedial action means any action performed under Section 108 of
the Uranium Mill Tailings Radiation Control Act of 1978.
(c) Open land means any surface or subsurface land which is not a
disposal site and is not covered by a building.
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(d) Working Level (WL) means any combination of short-lived radon
decay products in one liter of air that will result in the ultimate emis-
sion of alpha particles with a total energy of 130 billion electron volts.
(e) Dose equivalent means absorbed dose multiplied by appropriate
factors to account for differences in biological effectiveness due to the
type and energy of the radiation and other factors. The unit of dose
equivalent is the "rem."
(f) Curie (Ci) means the amount of radioactive material which
produces 37 billion nuclear transformations per second. One picocurie
(pCi) - 10-12 ci.
192.12 Standards
Remedial actions shall be conducted so as to provide reasonable
assurance that ~
(a) The average concentration of radium-226 attributable to residual
radioactive material from any designated processing site in any 5 cm
thickness of soils or other materials on open land within 1 foot of the
surface, or in any 15 cm thickness below 1 foot, shall not exceed 5 pCi/gm.
(b) The levels of radioactivity in any occupied or occupiable
building shall not exceed either of the values specified in Table B because
of residual radioactive materials from any designated processing site.
(c) The cumulative lifetime radiation dose equivalent to any organ
of the body of a maximally exposed individual resulting from the presence
of residual radioactive materials or byproduct materials shall not exceed
the maximum dose equivalent which could occur from radium-226 and its
decay products under paragraphs (a) and (b) of this section.
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192.13 Effective date
The standards of this Subpart shall be effective 60 days after
promulgation of this rule.
Subpart C — Exceptions
192.20 Criteria for exceptions
Exceptions to the standards may be justifiable under any of the
following circumstances:
(a) Public health or safety would be unavoidably endangered in
attempting to meet one or more of the requirements of Subpart A or
Subpart B.
(b) The goal of environmental protection would be better served by
not satisfying cleanup requirements for open land, Sec. 192.12(a) or the
corresponding part of Sec. 192.12(c). To justify an exception to these
requirements there should be a clearly unfavorable imbalance between the
environmental harm and the environmental and health benefits which would
result from implementing the standard. The likelihood and extent of
current and future human presence at the site may be considered in
evaluating these benefits.
(c) The estimated costs of remedial actions to comply with the
cleanup requirements for buildings, Sec 192.12(b) or the corresponding
part of Sec. 192.12(c), are unreasonably high relative to the benefits.
Factors which may be considered in this judgment include the period of
occupancy, the radiation levels in the most frequently occupied areas, and
8
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the residual useful lifetime of the building. This criterion can only be
used when the values in Table B are only slightly exceeded.
(d) There is no known remedial action to meet one or more of the
requirements of Subpart A or Subpart B. Destruction and condemnation of
buildings are not considered remedial actions for this purpose.
192.21 Remedial actions for exceptional circumstances
Section 108 of PL 95-604 requires the Secretary of Energy to select
and perform remedial actions with the concurrence of the Nuclear Regula-
tory Commission and the full participation of any State which pays part of
the cost, and in consultation, as appropriate, with affected Indian tribes
and the Secretary of the Interior. Under exceptional circumstances satis-
fying one or more of the conditions 192.20(a), (b), (c), and (d), the
Department of Energy may select and perform remedial actions, according to
the procedures of Sec. 108, which come as close to meeting the standard to
which the exception applies as is reasonable under the exceptional circum-
stances. In doing so, the Department of Energy shall inform any private
owners and occupants of affected properties and request their comments on
the selected remedial actions. The Department of Energy shall provide any
such comments to the parties involved in implementing Sec. 108 of
PL 95-604. The Department of Energy shall also inform the Environmental
Protection Agency of remedial actions for exceptional circumstances under
Subpart C of this rule.
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TABLE A
Arsenic 0.05 milligram/liter
Barium 1-0 milligram/liter
Cadmium 0.01 milligram/liter
Chromium 0.05 milligram/liter
Lead 0.05 milligram/liter
Mercury 0.002 milligram/liter
Molybdenum -• 0.05 milligram/liter
Nitrogen (in nitrate) 10.0 milligram/liter
Selenium 0.01 milligram/liter
Silver 0.05 milligram/liter
Combined radium-226 and radium-\228 5.0 pCi/liter
Gross alpha particle activity (including
radium-226 but excluding radon and uranium) 15.0 pCi/liter
Uranium 10.0 pCi/liter
TABLE B
Average Annual Indoor
Radon Decay Product Concentration
(including background) 0.015 WL
Indoor Gamma Radiation
(above background) 0.02 milliroentgens/hour
10
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
i. REPORT NO,
EPA 520/4-80-011
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Draft Environmental Impact Statement for Remedial
Action Standards for Inactive Uranium Processing
Sites
5. REPORT DATE
December. ' 1 Qftf)
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U. S. Environmental Protection Agency
Office of Radiation Programs (ANR-460)
401 M Street, S. W.
Washington, D. C. 20460
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
Draft
14. SPONSORING AGENCY CODE
200/03
15. SUPPLEMENTARY NOTES
16. ABSTRACT ^^ ————^
The Environmental Protection Agency is proposing standards for disposing of
uranium mill tailings from inactive processing sites and for cleaning up
contaminated open land and buildings. These standards were developed pursuant to
the Uranium Mill Tailings Radiation Control Act of 1978 (Public Law 95-604).
This Act requires EPA to promulgate standards to protect the environment and
public health and safety from radioactive and nonradioactive hazards posed by
uranium mill tailings at designated inactive processing sites. The Draft
Environmental Impact Statement examines health, technical, cost, and other
factors relevant to determining standards. The proposed standards for disposal of
the tailings piles cover radon emissions from the tailings to the air, protection
of surface and ground water from radioactive and nonradioactive contaminants, and
the length of time the disposal system should provide a reasonable expectation
of meeting these standards. The proposed cleanup standards limit indoor radon
decay product concentrations and gamma radiation levels and the residual radium
concentration of contaminated land after cleanup.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIEHS/OPEN ENDED TERMS
c. COSATI Field/Group
uranium mill tailings
Uranium Mill Tailings Radiation Control Act
of 1978
inactive uranium mill sites
radioactive waste disposal
radon
radium-226
19. SECURITY CLASS (ThisReport)
21. NO. OF PAGES
Release Unlimited
0. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
*U.8. GOVERNMENT PRINTING OFFICE:1981 341-082/202 1-3
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