United States Science Advisory EPA-SAB-RAC-ADV-01-001
Environmental Board (1400A) February 2001
Protection Agency Washington DC www.epa.gov/sab
&EPA TENORM: EVALUATING
OCCURRENCE AND RISKS
- AN SAB ADVISORY
A SCIENCE ADVISORY BOARD
(SAB) ADVISORY ON ERA'S
PROPOSED APPROACH FOR
EVALUATING OCCURRENCE AND
RISKS OF TECHNOLOGICALLY
ENHANCED NATURALLY
OCCURRING RADIOACTIVE
MATERIAL (TENORM)
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February 14, 2001
EPA-SAB-RAC-ADV-01-001
Honorable Christine Todd Whitman
Administrator
U.S. Environmental Protection Agency
1200 Pennsylvania Avenue, NW
Washington, DC 20460
Re: EPA's Proposed Approach for Evaluating Occurrence and Risks of
Technologically Enhanced Naturally Occurring Radioactive Material
(TENORM) - An SAB Advisory
Dear Ms. Whitman:
At the request of the Office of Radiation and Indoor Air (ORIA), the Radiation Advisory
Committee (RAC) of the Science Advisory Board (SAB) reviewed ORIA's proposed approach to
evaluating technologically enhanced naturally occurring radioactive material (TENORM) occurrence
and risks. The RAC also addressed the issue of whether ORIA is applying this approach appropriately
in its technical report for TENORM resulting from uranium mining. The Committee previously
reviewed a draft EPA scoping document (Diffuse NORM Wastes: Waste Characterization and
Preliminary Risk Assessment (RAE-9232/1-2)) addressing this issue and issued a report in 1994
(EPA-SAB-RAC-94-013). ORIA considered the RAC's comments in revising its approach to
TENORM, and developed three issue papers for review: a) Issue Paper #1: Proposed EPA Approach
to TENORM; b) Issue Paper #2: Proposed Outline for Uranium TENORM Report; and c) Issue
paper #3: Proposed TENORM Risk Assessment Methodology.
The RAC held a public meeting in Washington, D.C. on April 25 - 27, 2000, at which it was
briefed by, and had technical discussions with, ORIA staff and conducted writing sessions, producing a
preliminary draft Advisory. This Advisory addresses the charge questions (see below) as well as issues
beyond the charge identified during the public meetings.
In general, the RAC agrees that the general approach to TENORM and the risk assessment
methodology are reasonable. The proposed outline for the uranium TENORM Report is adequate.
ORIA has done a commendable job in putting these issue papers together.
The RAC had some difficulty responding to the charge questions because ORIA has not
clarified what actions might be undertaken as a result of the characterization reports or what types of
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materials are included in TENORM. In addition, the ORIA apparently has not yet developed detailed
adaptations of the relevant models.
The RAC responses to the specific charge questions posed by ORIA are as
follows:
a) Question 1: Is ORIA's general approach for characterizing TENORM in a given
technical report adequate?
With caution regarding the lack of specificity in regard to the TENORM effort, the
answer is conditionally yes. It is reasonable to prepare technical reports on an industry-
by-industry basis as each TENORM source can present unique features. Issue Paper
#2 lays out a reasonable overview of an appropriate process for accomplishing this
goal.
b) Question 2: Has the general approach been appropriately applied in the detailed outline
in the second issue paper for uranium mining TENORM?
The outline for uranium mining TENORM is generally adequate; however, approaches
that work well for the uranium mining assessment may not transfer easily to other
TENORM sectors.
c) Question 3: Is the risk assessment approach, as outlined in the third issue paper,
adequate for evaluating risks from uranium mining TENORM? In particular, have the
key exposure scenarios been considered?
The approach outlined in the third issue paper is adequate for evaluating the risks from
uranium mining TENORM. The list of exposure scenarios given in Issue Paper #2 is
extensive and covers most of the important ones except recreational activities (hunting,
hiking, fishing, etc.) which in the case of uranium mining, may be the most likely future
land use. Also, there are concerns about the lack of peer-reviewed publications
regarding use of the Prediction of Radiological Effects due to Shallow Trench
Operations models (PRESTO-EPA) for dose/risk assessment. Consequently, the RAC
recommends that:
1) the recreational scenario be considered
2) ORIA evaluate PRESTO to determine if it is the best tool to be applied to
other TENORM sources
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3) morbidity be considered in addition to cancer mortality when final risk estimates
are evaluated and presented
The RAC also addressed some issues beyond the charge. First, the RAC recommends that
ORIA provide a clear mission statement for the TENORM effort, that it clearly define the kinds of
materials included in TENORM, and document the adaptations of the key models. The RAC was
unclear about the intended scope of the TENORM documents. They appear to be focused on wastes.
The RAC generally supports a broader interpretation, not restricted by interagency boundaries, and
recommends that ORIA include products as well as wastes in the TENORM technical documents,
based on EPA's mandate to provide guidance to governmental agencies regarding protection of the
public from the harmful effects of radiation. The RAC recognizes that this is a policy issue but it is an
important consideration in addressing the charge questions. Last, ORIA should review the available
data obtained by other program offices such as CERCLA and the regional offices regarding TENORM
sources, in particular, uranium mines. The data from these sources could be useful in quantifying the
extent of the problem.
The RAC appreciates the opportunity to provide this advisory to you and we
hope that it will be helpful in developing EPA's approach to TENORM. We look forward to the
response of the Assistant Administrator for Air and Radiation to the comments and recommendations in
this report.
Sincerely,
/s/
Dr. William H. Glaze, Chair
Science Advisory Board
/s/
Dr. Janet A. Johnson, Chair
Radiation Advisory Committee
Science Advisory Board
/s/
Dr. Thomas F. Gesell, Chair
TENORM Subcommittee
Radiation Advisory Committee
Science Advisory Board
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NOTICE
This advisory has been written as part of the activities of the Science Advisory Board (SAB), a
public advisory group providing extramural scientific information and advice to the Administrator and
other officials of the Environmental Protection Agency (EPA). The Board is structured to provide
balanced, expert assessment of scientific matters related to problems facing the Agency. This report
has not been reviewed for approval by the Agency and, hence, the contents of this report do not
necessarily represent the views and policies of the EPA nor of other agencies in the Executive Branch
of the Federal Government. In addition, the mention of trade names or commercial products does not
constitute a recommendation for use.
Distribution and Availability: This Science Advisory Board report is provided to the EPA
Administrator, senior Agency management, appropriate program staff, interested members of the
public, and is posted on the SAB website (www.epa.gov/sab). Information on its availability is also
provided in the SAB's monthly newsletter (Happenings at the Science Advisory Board). Additional
copies and further information are available from the SAB Staff.
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ABSTRACT
On April 25 - 27, 2000 the Radiation Advisory Committee (RAC) of the EPA Science
Advisory Board (SAB) reviewed three issue papers which describe Office of Radiation and Indoor
Air's (ORIAs) approach to Technologically Enhanced Naturally Occurring Radioactive Material
(TENORM). Issue Paper #1 describes ORIA's general approach to TENORM; Issue Paper #2
provides a proposed outline for a specific source, uranium mining; and Issue Paper #3 presents the
proposed risk assessment methodology. ORIA requested advice on the adequacy of its proposed
approach, the application of the approach to uranium mining, as described in Issue Paper #2, and its
risk assessment methodology.
The RAC had difficulty responding to the questions posed by ORIA because the intent behind
the TENORM effort was not clear. With that reservation, the RAC agrees with ORIA's general
approach. However, the RAC recommends that ORIA provide a clear mission statement for the
TENORM program and define the types of materials to be included in its TENORM assessments, i.e.,
wastes only or wastes and products. The RAC supports a broader interpretation of ORIA's mission
and recommends that it include products as well as wastes in TENORM assessments. Specific issues
of concern include the lack of peer-reviewed publications regarding use of the PRESTO-EPA models
for risk assessment, differentiation between variability and uncertainty in the analyses, lack of inclusion
of a recreational scenario in the risk assessment, and potential interactions between hazardous materials
and radionuclides that may be present in TENORM sources.
KEYWORDS:Technologically Enhanced Naturally Occurring Radioactive Material (TENORM),
TENORM, TENORM wastes, TENORM waste products, TENORM sources,
TENORM Risks, TENORM Occurrence
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U.S. ENVIRONMENTAL PROTECTION AGENCY
SCIENCE ADVISORY BOARD
EXECUTIVE COMMITTEE
FY-2001
CHAIR
Dr. William Glaze, Professor and Director, Carolina Environmental Program, University of North
Carolina, Chapel Hill, NC
MEMBERS
Dr. Henry A. Anderson, Chief Medical Officer, Wisconsin Div.of Public Health, Madison,WI
Dr. Trudy Cameron, Professor, Department of Economics, University of California, Los Angeles, CA
Dr. Kenneth W. Cummins, Senior Advisory Scientist, California Humboldt State University, Arcata,
CA
Dr. Linda Greer, Senior Scientist, Natural Resources Defense Council, Washington, DC
Dr. Philip Hopke, Robert A. Plane Professor, Clarkson University, Potsdam, NY
Dr. Hilary I. Inyang, Director of Geoenvironmental and Energy Systems, University of NC, Charlotte,
NC
Dr. Janet A. Johnson, Senior Radiation Scientist, Shepherd Miller, Inc., Fort Collins, CO
Dr. Roger E. Kasperson, Executive Director, Stockholm Environment Institute, Stockholm, Sweden
Dr. Morton Lippmann, Professor, New York University School of Medicine, Tuxedo, NY
Dr. Raymond C. Loehr, Professor, Department of Civil Engineering, University of Texas at Austin,
Austin, TX
Dr. M. Granger Morgan, Head, Department of Engineering & Public Policy, Carnegie Mellon
University, Pittsburgh, PA
Dr. William H. Smith, Professor of Forest Biology, Yale University, New Haven, CT
Dr. Robert N. Stavins, Albert Pratt Professor of Business and Government, Harvard University,
Cambridge, MA
Dr. R. Rhodes Trussell, Senior Vice President, Montgomery Watson Consulting Engineers, Pasadena,
CA
ill
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Dr. Mark J. Utell, Professor of Medicine and Environmental Medicine, University of Rochester,
Rochester, NY
Dr. Terry F. Young, Senior Consulting Scientist, Environmental Defense Fund, Oakland, CA
SCIENCE ADVISORY BOARD STAFF
Dr. Donald G. Barnes, Staff Director/Designated Federal Officer, US Environmental Protection
Agency Science Advisory Board (1400A),1200 Pennsylvania Avenue, NW, Room 6450,
Washington, DC 20460
Ms. Diana Pozun, Program Specialist, US Environmental Protection Agency Science Advisory Board
(1400A),1200 Pennsylvania Avenue, NW, Room 6450, Washington, DC 20460
Ms. Betty B. Fortune, Office Assistant, US Environmental Protection Agency Science Advisory Board
(1400A),1200 Pennsylvania Avenue, NW, Room 6450, Washington, DC 20460
IV
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U.S. ENVIRONMENTAL PROTECTION AGENCY
SCIENCE ADVISORY BOARD
RADIATION ADVISORY COMMITTEE
April 25 - 27, 2000
CHAIR
Dr. Janet Johnson, Shepherd Miller, Inc., Ft. Collins, CO
MEMBERS
Dr. Lynn R. Anspaugh, University of Utah, Salt Lake City, UT
Dr. Vicki M. Bier, University of Wisconsin, Madison, WI
Dr. Bruce B. Boecker, Lovelace Respiratory Research Institute, Albuquerque, NM
Dr. Stephen L. Brown, R2C2 - Risks of Radiation & Chemical Compounds, Oakland, CA
Dr. Gilles Y. Bussod. Los Alamos National Laboratory, Los Alamos, NM
Dr. Thomas F. Gesell, Idaho State University, Pocatello, ID
Dr. Jill Lipoti, New Jersey Dept. of Environmental Protection, Trenton, NJ
Dr. Ellen Mangione, Colorado Department of Public Health and Environment, Denver, CO
Dr. John W. Poston, Sr., Texas A&M University, College Station, TX1
Dr. Genevieve S. Roessler, Radiation Consultant, Elysian, MN
CONSULTANTS
Dr. Richard W. Hornung, Institute for Health Policy and Health Services Research, University of
Cincinnati, Cincinnati, OH
Dr. Bobby R. Scott, Lovelace Respiratory Research Institute, Albuquerque, NM2
Dr. James E. Watson, Jr., Professor, Environmental Science & Engineering Department, University of
North Carolina, Chapel Hill, NC
SCIENCE ADVISORY BOARD STAFF
Ms. Melanie Medina-Metzger, Designated Federal Officer, US EPA Science Advisory Board
(1400A), US EPA, 1200 Pennsylvania Avenue, NW, Washington, DC 20460
1 Did not attend meeting of April 25-27, 2000, due to a schedule conflict
2 Did not attend meeting of April 25-27, 2000, but participated in the review
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Ms. Diana L. Pozun, Management Assistant, US EPA Science Advisory Board (1400A), US EPA,
1200 Pennsylvania Avenue, NW, Washington, DC 20460
VI
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TABLE OF CONTENTS
1. EXECUTIVE SUMMARY 1
2. INTRODUCTION 6
2.1 Background 6
2.2 Charge 6
3. RESPONSE TO THE CHARGE 7
3.1 Is EPA's general approach for characterizing TENORM in a given technical report
adequate? 7
3.1.1 Procedural Issues 7
3.1.2 Technical Issues 8
3.2 Has the general approach been appropriately applied in the detailed outline in the second
issue paper for uranium mining TENORM? 9
3.2.1 Procedural Issues 9
3.3 Is the risk assessment approach, as outlined in the third issue paper, adequate for
evaluating risks from uranium mining TENORM? In particular, have the key exposure
scenarios been considered? 11
3.3.1 Risk Assessments 12
3.3.2 Models 13
3.3.3 Exposure Scenarios 15
3.3.4 Case Studies 16
3.3.5 232Th and its Decay Products 16
3.3.6 Direct Gamma Exposure 16
3.3.7 Resuspension 16
3.3.8 Uncertainly Analysis 17
4. ISSUES BEYOND THE CHARGE 18
4.1 Intended Scope of the TENORM Documents 18
4.2 Use of Existing Data from Other Programs Within EPA 19
4.3 Background Evaluation for TENORM Sites 20
4.4 Education and Risk Communication 20
5. SPECIFIC COMMENTS BY COMMITTEE PARTICIPANTS 21
APPENDIX A- GLOSSARY OF TERMS AND ACRONYMS A-l
REFERENCES R-l
vu
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1. EXECUTIVE SUMMARY
At the request of the EPA's Office of Radiation and Indoor Air (ORIA) the Radiation Advisory
Committee (RAC) of the Science Advisory Board (SAB) reviewed three issue papers, which describe
ORIA's approach with regard to Technologically Enhanced Naturally Occurring Radioactive Material
(TENORM) (EPA, 2000a; 2000b; 2000c). The first paper describes ORIA's approach to TENORM
in general. The second paper is a proposed outline for a uranium mining TENORM report. The third
paper describes ORIA's proposed risk assessment methodology. The RAC held a public meeting in
Washington, D.C. on April 25-27, 2000 at which it was briefed by, and had technical discussions with,
ORIA staff, and conducted an editing session producing a preliminary draft Advisory.
ORIA requested the advice of the RAC on the adequacy of its proposed approach to
evaluating TENORM occurrence and risks, with specific regard to the approach for characterizing
TENORM, the application in the proposed outline for the uranium mining technical report, and the risk
assessment approach. In general, the RAC had some difficulty responding to the charge questions
because ORIA has not clarified what actions might be undertaken as a result of the characterization
reports or what kinds of materials are included in TENORM, i.e., wastes only, building materials, etc.
The RAC agrees that the approach to TENORM in general and uranium mine TENORM specifically,
as described in the issue papers, is reasonable and notes that ORIA has addressed the comments from
its 1994 review (EPA-SAB-RAC-94-013) of the document Diffuse NORM Wastes: Waste
Characterization and Preliminary Risk Assessment (RAE 9232/1-2).
The specific Charge questions are:
a) Is EPA's general approach for characterizing TENORM in a given technical report
adequate?
With the reservations described previously regarding the lack of specificity in the
TENORM effort, the answer is conditionally "yes." It is reasonable to prepare
technical reports on an industry-by-industry basis, as each can present unique features.
Issue Paper #2 provides a reasonable overview of an appropriate process for
characterizing uranium mining-related TENORM.
The RAC approves of ORIA's intent to use "best" estimates of parameters for the
point estimates and to treat uncertainty and variability with a distributional approach.
The RAC has considered ORIA's intent to use best estimates (point estimates) of
uncertain parameters for generating best estimates (point estimates) of risk. While
recognizing the practicality of this approach, the RAC notes that calculating best
estimates of risk considering full variability/uncertainty distributions generally gives a
different best estimate of risk than one gets using best estimates of uncertain model
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parameters. The variability/uncertainty distribution approach is considered more
reliable and information on the full risk distribution is generated. Also, the Issue Papers
should clearly distinguish variability (true variation from site to site or from person to
person) from uncertainty (lack of knowledge about the true value of a parameter for a
particular set of conditions).
ORIA's use of the Prediction of Radiological Effects due to Shallow Trench Operations
models (PRESTO-EPA) for assessment of risks from uranium mining is reasonable;
however the Committee Members who reviewed the literature on PRESTO-EPA felt
that the models have not been adequately peer-reviewed. Models used for regulatory
purposes should have a good track record of publication in peer-reviewed journals.
ORIA should assess the applicability of the PRESTO-EPA models to other situations
and consider using more appropriate dose/risk assessment tools. The RAC also
recommends that the issues of bioavailability, teachability, and radon emanation rates
from various sources of TENORM be addressed specifically as suggested by the
National Academy of Sciences Committee (NAS 1999).
The time frame and exposure conditions that are the focus of the risk assessment for
any TENORM source should be made clear in all documents intended for use by the
public. The affected public will be interested in risk estimates applicable to their own
exposure histories and should be warned that the prospective risk estimates provided in
the TENORM documents may not be applicable to their cases. In view of the
uncertainty (and continuing controversy) about the risk of low doses of radiation, the
RAC recommends that ORIA provide appropriate disclaimers with the risk estimates it
may generate for TENORM sources of exposure.
With regard to characterization of sources, ORIA has only limited success in obtaining
information about TENORM quantities and radionuclide concentrations. It appears
that voluntary disclosure by the affected parties may not be forthcoming. ORIA should
indicate how it intends to fill the data gaps.
b) Charge Question #2: Has the general approach been appropriately applied in the
detailed outline in the second issue paper for uranium mining TENORM?
The outline for uranium mining TENORM seems generally adequate. However,
approaches that work well for the uranium mining assessment may not transfer easily to
other TENORM sectors in which TENORM is emitted to air (e.g., from coal-burning
facilities such as electric power plants) or occurs as a product (e.g., in building materials
such as concrete blocks). While the proposed outline of the report appears
comprehensive, a definitive response to the charge question can be given only after
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seeing an initial draft with actual data and results of calculations.
In its discussion of uncertainty, it is essential for ORIA to make the distinction between
uncertainty and variability, as discussed above. It would also be useful to include a
section on "Research Needs" if the uncertainty analysis suggests that additional
investigations are required to support any decisions to be made based on the
assessment.
The section on "Other Hazardous Constituents" is important and should include a
discussion of how these constituents might affect the total radiation risk. When other
hazardous constituents can change the characteristics of the TENORM, i.e., to make it
more mobile in the environment, affect its toxicity, or change risk in any way, that
should be made explicit.
In its outline for uranium TENORM report, ORIA has stated that it will present
background radiation and risk information. Because this is an important issue and
there are significant variations in background radiation, an explanation of how ORIA
plans to determine appropriate radiation background levels is recommended.
It is not clear how far the "radiation overview" (Issue Paper #2, Item VT.A) would be
developed. ORIA should consider whether the non-specific radiation primer will dilute
the report and whether the entire report should have a lay-level version, either as a
separate section, or as a companion volume.
c) Charge question #3: Is the risk assessment approach, as outlined in the third issue
paper, adequate for evaluating risks from uranium mining TENORM? In particular,
have the key exposure scenarios been considered?
Once more, with reservations regarding specificity, the approach outlined in the third
issue paper seems adequate for evaluating the risks from uranium mining TENORM.
The lists of exposure scenarios in TENORM Issue Paper #3 (EPA, 2000c) as well as
in TENORM Issue Paper #2 (EPA, 2000b) are quite extensive and cover most of the
important exposure situations except recreational use. In the case of uranium mines,
recreation may be the most likely future land use. The RAC recommends that
scenarios that can reasonably be expected to be encountered by a significant number of
people should have the highest priority.
While Issue Paper #3 (EPA, 2000c) specifies evaluation of risks from TENORM
wastes and products, the emphasis in Issue Paper #2 (EPA, 2000b) seems to be on
"disposal." A broader interpretation might be considered. The RAC recommends that
ORIA provide a comprehensive discussion of the scope of the analysis, clearly
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identifying what it covers and what it does not cover.
The RAC's general support of the approach might be strengthened after further review
of the documentation for the PRESTO-EPA and MICROSfflELD (a single pathway
model designed to calculate external gamma exposure rates from radiation sources of
various sizes and shapes) models and ORIA's detailed plans for selection of parameter
values and distributions for the uncertainty analysis. As noted previously, the Members
of the Committee who reviewed the literature provided by ORIA regarding the
PRESTO-EPA models felt that the codes have not been adequately peer-reviewed.
The risk assessment methodology described in Issue Paper #3 is focused on cancer
mortality. As it has in past advice to ORIA, the RAC recommends that morbidity be
considered in addition to cancer mortality when final risk estimates are made.
The charge questions posed by ORIA and the RAC's responses cover many of the important
considerations regarding ORIA's approach to TENORM characterization. However, the RAC also
addressed several issues beyond the charge that were identified during the public meetings:
a) The RAC recommends that ORIA provide a clear mission statement for the TENORM
effort, that it clearly define the kinds of materials included in TENORM, and document
the adaptations of the key models. Also, ORIA should review the available data
obtained by other program offices such as the Comprehensive Environmental Response
and Liability Act (CERCLA) and the regions regarding TENORM sources, in
particular, uranium mines. The data from these sources could be useful in quantifying
the extent of the problem. Environmental media concentration data and gamma
exposure rate data gathered in support of site-specific risk assessments could be used
to validate the models for particular types of sites.
b) In Issue Paper #1, page 10, ORIA proposes to promote and provide education.
ORIA should consider as its first educational opportunity scientific societies such as the
Conference on Radiation Control Program Directors and the Health Physics Society.
Consideration should be given to presentation of papers at meetings and papers in
society publications.
c) The RAC supports ORIA's intent to make the TENORM documents useful to a broad
audience. The usefulness of the document will be limited if various parts of the risk are
left out of the risk assessment because they are regulated by different agencies to
differing degrees. The audience will be left with an inaccurate picture consisting of a
sum of partial risks derived from different agency risk assessments which are not
designed to be aggregated.
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d) The RAC was unclear about the intended scope of the TENORM documents. Under
the Executive Order 10831 and Reorganization Plan Number 3, EPA is charged with
developing Federal Guidance, which is defined as a set of guidelines developed by
EPA, for use by Federal and State agencies responsible for protecting the public from
the harmful effects of radiation. As it is the EPA's goal to protect the public, the RAC
generally supports a broader interpretation not restricted by the interagency boundaries
and recommends that ORIA include products as well as wastes in the TENORM
technical documents. The RAC recognizes that this is a policy issue but it is an
important consideration in addressing the charge questions.
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2. INTRODUCTION
2.1 Background
The EPA's Office of Radiation and Indoor Air (ORIA) is formulating its plans for evaluating the
occurrence and risks of technologically enhanced naturally occurring radioactive materials (TENORM)
and identifying opportunities for abatement. As a part of this process, ORIA has requested that the
Radiation Advisory Committee (RAC) review three issue papers, which provide an overview of these
plans, and provide the specific approach proposed for uranium mining (EPA, 2000a; 2000b; 2000c).
The first paper provides ORIA's intended approach to TENORM. The second paper is a proposed
outline for a uranium mining TENORM report. The third paper provides ORIA's proposed
methodology for risk assessment as applied to TENORM. The RAC held a public meeting in
Washington, D.C. on April 25 - 27, 2000 at which it was briefed by, and had technical discussions
with, ORIA staff and conducted an editing session on June 5, 2000 producing a preliminary draft
Advisory.
2.2 Charge
The specific charge to the RAC for this review was to respond to the following questions:
a) Is EPA's general approach for characterizing TENORM in a given technical report
adequate?
b) Has the general approach been appropriately applied in the detailed outline in the
second issue paper for uranium mining TENORM?
c) Is the risk assessment approach, as outlined in the third issue paper, adequate for
evaluating risks from uranium mining TENORM? In particular, have the key exposure
scenarios been considered?
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3. RESPONSE TO THE CHARGE
ORIA requested the advice of the RAC on the adequacy of its proposed approach to
evaluating technologically enhanced naturally occurring radioactive material (TENORM) occurrence
and risks, specifically with regard to approach for characterizing TENORM, the application in the
proposed outline for the uranium mining technical report, and the risk assessment approach. ORIA
posed three specific charge questions to the RAC. The questions and the RAC's responses are
discussed in detail in this section.
3.1 Is EPA's general approach for characterizing TENORM in a given technical report
adequate?
As a general guide for the analysis, the Issue Papers provided to the Committee are reasonable.
Because they lack specificity in many areas, the RAC is unable to comment fully on their scientific
merits. Documentation of the PRESTO-EPA (Prediction of Radiological Effects due to Shallow
Trench Operations) and MICROSHIELD (a single pathway model designed to calculate external
gamma exposure rates from radiation sources of various sizes and shapes) model families that will be
used to conduct the analysis may help the RAC understand better what will be done, but how
parameters will be selected for the models may remain unclear until a draft assessment document is
produced.
The RAC notes that ORIA has carefully considered its 1994 comments on the Diffuse NORM
Assessment document (EPA-SAB-RAC-94-13) and responded positively to most of them. The RAC
also notes that ORIA has changed its strategy for the TENORM characterization from a screening
document, designed to differentiate TENORM sources with little potential for health risk from those
deserving Agency attention, to a series of descriptive reports covering each of the sources without a
prior judgment about the need for abatement. Although ORIA may use indicators of risk as criteria for
deciding which sources to investigate first, it intends to use other criteria as well and does not appear to
have eliminated any potential TENORM sources from its sphere of interest.
With the caution regarding lack of specificity given above, the answer to the initial Charge
question is conditionally "yes." It seems quite reasonable to prepare documents on an industry-by-
industry basis, as each can present unique features. The issue paper lays out a reasonable overview of
an appropriate process for characterizing TENORM.
3.1.1 Procedural Issues
ORIA has not clarified what actions might be undertaken as a result of the characterization
reports. Various types of potential actions might require different data quality objectives. The RAC
recommends that ORIA provide a clear mission statement for the TENORM program.
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The kinds of materials to be considered TENORM should be clearly delineated. Although in
some parts of the issue papers, ORIA mentions TENORM-containing products (e.g., building
materials) as proper subjects for evaluation, in other parts only TENORM wastes appear to be
considered. The RAC recommends that TENORM be defined clearly. This point is discussed further
in Section 4 (Issues Beyond The Charge).
3.1.2 Technical Issues
The RAC has considered ORIA's intent to use best estimates (point estimates) of uncertain
parameters for generating best estimates (point estimates) of risk. While recognizing the practicality of
this approach, the RAC notes that calculating best estimates of risk considering full
variability/uncertainty distributions generally gives a different best estimate of risk than one gets using
best estimates of uncertain model parameters. The variability/uncertainty distribution approach is
considered more reliable and information on the full risk distribution is generated. In addition, the Issue
Papers do not clearly distinguish variability (true variation from site to site or from person to person)
from uncertainty (lack of knowledge about the true value of a parameter for a particular set of
conditions). Uncertainty can be reduced by research, but inherent variability cannot. Moreover,
variability has policy implications regarding risk equity, whereas uncertainty does not (Hattis and
Anderson, 1999). The RAC recommends that ORIA clearly separate variability and uncertainty in its
distributional analyses, using a two-dimensional Monte Carlo analysis if feasible.
ORIA has proposed to use the PRESTO-EPA models for the analysis of the risks from
TENORM in the uranium mining sector. However, the materials provided to the RAC were not clear
on whether or not ORIA also intends to make the PRESTO-EPA models its choice for the analysis of
other TENORM sectors. Although PRESTO-EPA models may be adequate for the analysis of
waste-in-place TENORM sources, such as the waste piles found in uranium mining, they may be
inadequate for other TENORM sources in which TENORM is emitted to air (e.g., from coal-burning
facilities such as electric power plants) or occurs as a product (e.g., in building materials such as
concrete blocks).
The Committee found that the PRESTO-EPA model family has not been adequately peer
reviewed. Any model used for regulatory purposes should have a good track record of publication in
peer-reviewed journals. Otherwise, members of the public can be subjected to unrealistic regulation at
costs that are unjustified. A detailed discussion of this issue is provided in section 3.3 of this report.
It is not clear how ORIA intends to take into account the bioavailability, teachability, and radon
emanation rates from various sources of TENORM, as suggested by the National Academy of
Sciences Committee charged with conducting the study of TENORM (NAS, 1999). For example, the
radon emanation rates for pipe scale differ significantly from the emanation rates for uranium mine waste
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rock and protore.1 The RAC recommends that these issues be addressed specifically in future
documentation of the TENORM program.
Although the RAC realizes that ORIA's principal focus for TENORM is on assessing risks
prospectively in order to judge the need for remedial activities, this focus was not made clear in the
materials provided. The time frame and exposure conditions that are the focus of the risk assessment of
any TENORM source should be made clear in all documents intended for use by the public. The RAC
further notes that the health risk for future exposures to an individual can depend on his or her history of
past exposures. The projected risk for a lifetime of exposure for a person born today and residing near
the site may be different from that for a current resident who might have experienced higher or lower
exposures in the past than suggested by current conditions. The affected public will be interested in risk
estimates applicable to their own exposure histories and should be warned that the prospective risk
estimates provided in the TENORM documents may not be applicable to their cases.
In view of the uncertainty (and continuing controversy) about the risk of low doses of radiation,
the RAC recommends that ORIA provide appropriate disclaimers about any risk estimates it may
generate for TENORM sources of exposure. Issue Paper #3 is not entirely clear on the extent to
which ORIA will report dose as well as risk estimates in its TENORM assessments. Because dose is
one step less controversial than risk, the RAC can support the reporting of both dose and risk, with the
proviso that any inconsistencies in conclusions be explained. The RAC Advisory (SAB, 1999) on
Federal Guidance Report No. 13 (EPA, 1998) discusses the difficulty of reconciling risk estimates
derived via effective dose calculations and direct risk calculations
ORIA has admitted lack of success in obtaining information about TENORM quantities and
radionuclide concentrations from various sources. It appears that voluntary disclosure by the affected
parties may not be forthcoming. ORIA should indicate how it intends to fill the data gaps.
3.2 Has the general approach been appropriately applied in the detailed outline in the second
issue paper for uranium mining TENORM?
3.2.1 Procedural Issues
Again with the reservations about specificity given in the Introduction, the outline for uranium
mining TENORM seems generally adequate. ORIA justified its choice of uranium mining for first
consideration based on data availability, the number of sites potentially presenting TENORM issues,
and concerns by Native American communities. It is not clear whether this group of sources would
score high on either a maximum individual or population risk scale. Moreover, uranium mining has a
high profile for public perception of radiation risk, while many of the other TENORM sectors do not.
Protore is material that does not meet the grade requirements for economic processing at the time it is removed , but is stored
for future use in the event that it becomes economical to mill.
-------
Approaches that work well for the uranium mining assessment may not transfer easily to other
TENORM sectors. While the proposed outline of the report appears comprehensive, a definitive
response to the charge question can be given only after seeing an initial draft with actual data and results
of calculations. With these caveats, the RAC offers the following responses to Charge Question #2.
The RAC notes that the outline does not contain a separate section for either risk
characterization or uncertainty analysis, although the section labeled "Summary of Risk Assessment"
might be intended to cover the former. Agency guidance for risk assessments suggests that both should
be important components of the final report. It is essential for ORIA to make the distinction between
uncertainty and variability as discussed above. It would also be useful to include a section on
"Research Needs" if the uncertainty analysis suggests that additional investigations are required to
support any decisions to be made based on the assessment.
The list of exposure scenarios in Issue Paper #2 is quite extensive and covers most of the
important potential exposure situations. However the emphasis in Issue Paper #2 seems to be on
"disposal," whereas a broader interpretation might be considered. The RAC recommends that ORIA
provide a comprehensive discussion of the scope of the analysis, clearly identifying what it covers and
what it does not cover. Inclusion of an "onsite resident and farmer" seems to imply that the assessment
would limited to post closure activities unless there have been onsite residents and farmers prior to
closure, which seems unlikely.
3.2.2 Technical Issues
In general, there is some confusion about the time scale of the assessment scenarios. ORIA
should clarify whether the assessments include projected land uses at some time in the future. It may be
possible after some experience is gained to reduce the number of scenarios by eliminating those that do
not pose significant individual or population risks. Focusing on a smaller number of land uses would
allow more complete analyses of those few critical exposure scenarios. Not all lands are suitable for
agriculture or even full time residency. For this reason a scenario for recreational land use should be
considered (see Section 3.3 for more detail). The RAC recommends clarification of the scenarios to
be assessed and some prioritization based on potential risk.
The RAC recommends that ORIA consider other sources of information on existing mines.
The National Institute of Occupational Safety and Health (NIOSH) maintains a computer file of mines
measured for the uranium miner epidemiology study. Also the RAC recommends that ORIA clarify the
full extent of intended coverage. For example, to what extent is the potential for heap-leach extraction
of uranium from materials accumulated in other types of mining (non-uranium) considered? If this
practice occurs, would that be included in the uranium mining TENORM report or in another sector
report?
The section on "Other Hazardous Constituents" is a worthwhile endeavor, because the greatest
10
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risks from a given sector may not be radiological. For example, uranium poses radiological risks but is
also a chemical nephrotoxin. Other hazardous materials, such as asbestos and crystalline silica, should
be included in the risk analysis. These materials may be of concern primarily during blasting operations
at open-pit mines. With regard to risks from impacted water resources, risk assessment by simple
comparison to drinking water maximum contaminant levels (MCLs) or other standards may not be as
useful as the risk assessment approach for radionuclides because MCLs can contain considerations that
are not risk-related, such as feasibility of attainment.
When discussing "other hazardous constituents" that may be present with the TENORM,
ORIA should also specify how these constituents might affect the radiation risk. When other hazardous
constituents can change the characteristics of the TENORM, to make it more mobile in the
environment, or to affect its toxicity or change its risk in any way, that should be made explicit. In the
low activity mixed waste advisory, the RAC was concerned with how hazardous components would
affect the mobility or volatility of the radioactive component. The same concern applies to the
TENORM assessments.
To the extent practicable, ORIA should define the "soil radiation background levels" and
surface and groundwater background levels. The National Academy of Sciences Committee that
examined the basis for the EPA's TENORM guidance urged EPA to include in its assessment of
TENORM-related risks an assessment of existing background radiation and the risks that this radiation
contributes to overall risks from radiation exposure. In its proposed outline for uranium TENORM
report, ORIA has stated that it will present background radiation and risk information. Since this is an
important issue and since there are significant variations in background radiation, an explanation of how
ORIA plans to determine appropriate radiation backgrounds is recommended.
The ORIA approach to TENORM characterization calls for a mix of technical reporting (most
of the report) and lay-level presentation (VI-A, Radiation Overview). ORIA should consider whether
the non-specific radiation primer will dilute the report and whether the entire report should have a lay-
level version, either as a separate section, or as a companion volume.
It is not clear how far the "radiation overview" (Issue Paper #2, Item VIA) would be
developed. The focus should be on radiogenic cancer, and possible genetic effects would have to be
mentioned, although such have not been observed in humans. It may be desirable also to note the
recent information on the possibility of other non-cancer effects (e.g., Shimizu, et a/., 1999; Ivanov et
al, 2000).
3.3 Is the risk assessment approach, as outlined in the third issue paper, adequate for
evaluating risks from uranium mining TENORM? In particular, have the key exposure
scenarios been considered?
Once more, with the reservations regarding specificity given in the Introduction, the approach
11
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outlined in the third issue paper seems adequate for evaluating the risks from uranium mining
TENORM. As mentioned in the response to the second charge question, the list of scenarios is
extensive and probably incorporates the highest individual risks but the Uranium Mining Outline (Issue
Paper #2) addresses only wastes and not products. However, the RAC offers Table 1 as a suggested
approach to systematically defining and communicating the scenarios to be considered. The RAC
offers the following detailed responses to Part 3 of the charge.
Table 1. Important exposure pathways for the various exposed individuals or populations
Exposure Pathway
Direct gamma
Inhalation of Rn and decay products
Inhalation of dust
Ingestion of soil
Ingestion of fish
Ingestion of food contaminated by dust
Ingestion of food, root uptake from soil
Ingestion of drinking water, well
Ingestion of food contaminated by well water
Radiation from TENORM in pipes as structural
supports in homes
Radiation from TENORM in road pavement &
aggregate
Radiation from TENORM in bldg materials
Ingestion of river sediments
Ingestion of river water, ground water pathway
Ingestion of river water, runoff pathway
Ingestion of food contaminated by river water
Ingestion of surface water
Worker*
X
X
X
X
--
--
--
--
--
--
--
--
--
--
On- site
Individual
X
X
X
X
X
X
X
X
X
--
--
--
--
--
Adjacent
Individual
X
X
X
X
X
X
X
X
X
X
X
X
--
--
--
General
Population
X
X
X
X
X
X
X
--
--
--
--
X
X
X
X
--
Rec-
reational
X
X
X
X
X
--
--
--
--
--
--
--
--
X
*It is important to note that a worker may also be exposed to radiation from TENORM as an on-site or adjacent resident.
3.3.1 Risk Assessments
The RAC recommends that ORIA provide more detail on how risk assessments will be
approached, discuss the impact of the choice of model, and indicate whether site-specific risk will be
calculated for each case study. It is not clear from the third Issue Paper how far into the future the
doses and risks will be projected. ORIA should consider whether the appropriate time horizon should
12
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be the same for all TENORM sources. The scenarios to be included are strongly dependent upon the
time frame of the study.
As noted previously, the contribution to risk from hazardous constituents other than
radionuclides should be calculated. ORIA should consider whether there will be enough information to
determine risk from the other, non-radioactive, hazardous constituents as well as the radiation risk. The
radiation risk may not be the limiting factor (most risk) in all cases.
In several places, ORIA indicates that it will estimate maximum individual risk, but the concept
of "maximum" is not well defined. Hypothetical exposure scenarios that are possible but unlikely can
lead to risk estimates many times higher than those likely to be experienced by real individuals. The
RAC recommends limiting the analysis to scenarios that can reasonably be expected to be encountered
by a significant number of people. Perhaps the principal focus should be on the 5-95 percentile range
without reporting the "maximum" and "minimum" values from the Monte Carlo analyses. Such
approach seems to be implied by ORIA's response to the RAC recommendations regarding issue 5
(page 11 of the issue paper).
The RAC recommends that ORIA consider morbidity risk in addition to cancer mortality when
final risk estimates are made. The RAC notes that it has made this recommendation in several previous
contexts. The RAC also notes that publications associating non-cancer morbidity with radiation have
appeared very recently in the in the literature (Shimizu, et al., 1999; Ivanov et a/., 2000).
The materials that are "TENORM" for the uranium-mining industry according to ORIA's policy
should be clearly specified in this document. Materials that might cause risk to the public, but which are
not included in this assessment, should also be clearly identified with at least a qualitative statement of
how the assessed and un-assessed sources might differ in terms of risk to the public. The RAC also
recommends that the risk assessment approach consider the end user of recycled products.
3.3.2 Models
ORIA has proposed to use the PRESTO-EPA models as its multimedia modeling tool for the
analysis of the risks from TENORM in the uranium mining sector. EPA developed the PRESTO-EPA
family of computer codes to aid in developing standards for disposing of low-level radioactive waste.
The PRESTO-EPA-CPG and PRESTO-EPA-POP models have been used to generate dose/risk
estimates to support: (1) the proposed Low-level Radioactive Waste Rule (1987); (2) the proposed
Low Activity Mixed Waste Rule (1998); and (3) the draft Naturally Occurring Radioactive Materials
Report.
The materials provided to the RAC were not clear on whether or not ORIA also intends to
make the PRESTO-EPA model family its choice for the analysis of TENORM sources other than
uranium mine wastes. Although PRESTO-EPA models may be adequate for the analysis of
13
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waste-in-place TENORM sources, such as the waste piles found in uranium mining, they may be
inadequate for other TENORM sources from which TENORM is emitted to air (e.g., from
coal-burning facilities such as electric powerplants) or occurs as a product (e.g., in building materials
such as concrete blocks).
The Committee did not find sufficient evidence that the PRESTO-EPA model family had been
adequately peer-reviewed or that the basic structure and features of the model had been published in a
peer-reviewed journal. It appears that the most recent extensive peer review of the PRESTO-EPA
models was carried out in 1984. Since that time, considerable new knowledge has been gained related
to radiation risk assessment for radionuclide contaminated media, and the capability of modeling
radionuclide movement through various media has been improved significantly. However, there is no
evidence in the material provided to the RAC that PRESTO-EPA models have been critically reviewed
in light of this new knowledge and whether any attempt has been made to include model parameter
uncertainty in risk assessment with PRESTO-EPA models. The proposal to link the PRESTO-EPA
models with the @RISK (a multi-variance uncertainty model) to handle uncertainty analysis may be
adequate to evaluate uncertainty, but the RAC was not provided with any evidence that this technique
has been successfully implemented.
It is unclear whether components of the PRESTO-EPA models have been evaluated to see
whether they actually model the process they represent in a scientifically valid way. This comment
relates to the possibility that inappropriate component models may be incorporated into the PRESTO-
EPA models. In 1983, a quality assurance audit was conducted related to the PRESTO-EPA models
by Inter Systems, Inc (ISI). However, they state in their final report (ISI, 1983) that:
"ISI only considered the coding of the equations and the logic presented in the documentation
package."
"No assessment of the appropriateness of equations used to simulate processes was made."
Recently, additional improvements have been made in PRESTO-EPA model family. Based on
information provided to us, it appears that PRESTO-EPA-POP has been replaced by
PRESTO-EPA-CLNPOP. Also PRESTO-EPA-CPG has been replaced by
PRESTO-EPA-CLNCPG. Model applicability has been expanded to include in addition to
radioactive waste disposal, soil cleanup, agricultural land application, land reclamation, accidental spills,
in addition to combining PRESTO-EPA-CPG and PRESTO-EPA-POP into a common system. Thus,
the need for peer review applies to the new models, and it is unclear whether the changes have been
subjected to peer review by experts. The Members of the RAC have not seen a single publication
concerning the workings and details of the PRESTO models in a peer-reviewed journal. If there have
been no peer-reviewed publications, the appropriateness of the new models for their intended use
cannot be adequately evaluated based on presently available information.
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A non-peer reviewed paper, presented at the Waste Management 97 conference, compared
PRESTO-EPA predictions with real data. The report (Rogers et al., 1997) stated that the
methodology used in PRESTO-EPA-CLNCPG and PRESTO-EPA-CLNPOP is less conservative
and more realistic than that used in Residual Radioactive Materials Guidelines (the Department of
Energy model RESRAD). This was based on comparing predicted and observed radionuclide
concentrations in well water at the Savannah River facility for radionuclides transported to the well from
a nearby burial site. However, what was not stated was that for two thirds of the cases evaluated,
model predictions based on the PRESTO models were orders of magnitude in error. For tritium,
PRESTO-EPA-CLNCPG over-predicted by a factor of 2.4; for Tc-99 the over prediction was a
factor of 435. PRESTO-EPA-CLNCPG under predicted concentrations of 1-129 by a factor of 260.
The purpose of the evaluation, reported in this paper, was to compare the performance of the PRESTO
models to the performance of the RESRAD code. The PRESTO-EPA-CLNCPG predictions were
closer to measured values than the RESRAD predictions. However, given the magnitude of the
difference between the concentrations calculated by PRESTO-EPA-CLNCPG and the measured
concentrations, ORIA should carefully assess the applicability of PRESTO to all TENORM sources.
The RAC also encourages additional comparisons between the models and field data when feasible.
A second paper provided to the RAC by ORIA presents a comparison of results from
PRESTO and MMSOILS (a multi-media contaminant transport, fate, and exposure model for soils) in
which the results differed by about an order of magnitude (Mills et al., 1999).
While the RAC recognizes that the use of PRESTO in the context of evaluation of TENORM
does not have a regulatory purpose, any model used for such purposes should have a good track
record of publication in peer-reviewed journals. Otherwise, members of the public can be subjected to
unrealistic regulation at costs that are unjustified. ORIA should consider using more appropriate
modeling tools for emissions to air.
3.3.3 Exposure Scenarios
The risk assessment approach should specifically include recreational use and resident and non-
resident rancher exposure scenarios. Many uranium mining facilities are located in remote areas not
suitable for farming. These areas are most likely to be used in the future for recreational purposes and
stock grazing. The RAC recommends including diverse recreational scenarios such as hunting, hiking,
fishing, golf, hiking, camping, mountain biking, motorcycling, snowmobiling, all terrain vehicle (ATV)
use, etc. in its risk analyses. In addition to direct exposures to recreationists, ORIA should consider
impacts such as erosion and resuspension from ATV and other off-road vehicle use, and the effect of
creating an irrigated golf course on the rates of contaminant transport to ground water. Assessing risks
based only on a resident or even a non-resident farming scenario may result in an unreasonable estimate
of potential future risks.
15
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While the PRESTO-EPA models may not specifically deal with the recreational scenario, at
least for uranium mining, recreation may need to be considered using a manual approach. It is not
sufficient to simply adjust the residence times to account for a transient population. Pathways such as
direct gamma exposure, ingestion of surface water, radon decay product inhalation, and ingestion offish
will have different exposure conditions from those assumed for the resident and non-resident farmer.
3.3.4 Case Studies
In Case Studies, some unique pathways are discussed. Some of them are not generally
applicable. For instance, in the Orphan Mine in the Grand Canyon, the exposure pathway of tourists
drinking from the spring containing contaminated water is mentioned. In this case, a risk should be
calculated for a transient population.
3.3.5 232Th and its Decay Products
ORIA should address potential exposure to 232Th and its decay products in the technical report
for uranium mining. While, in general, natural thorium concentrations are in the range of background, in
uranium mineralized areas (NCRP, 1993) this may not be the case in some specific situations. The
radon species to be studied might include 220Rn, because some ore bodies contain substantial amounts
of 232Th. Although this radon isotope has a short half life, some of its progeny have much longer half
lives; 220Rn might be of significance given high enough concentrations of its 232Th parent in ore bodies or
overburden piles.
3.3.6 Direct Gamma Exposure
The RAC recommends that ORIA clarify what is meant by "direct gamma exposure."
Depending upon location, the most significant source might be direct radiation and skyshine from
overburden piles. In other situations, direct gamma exposure might include external gamma exposure
from contaminated particles that have been suspended from sources and deposited in the vicinity of the
individuals' homes. The latter source of exposure might be important over the long term.
3.3.7 Resuspension
The treatment of resuspension in the PRESTO-EPA models utilizes variations of the
resuspension-factor approach, which is a time-dependent factor applied to the deposition density of a
radionuclide. However, this approach was developed for application to fresh deposits of radionuclides
on a soil surface and includes the effect of the deposited material weathering into the soil surface. This
approach is not appropriate for a source that is mixed throughout a soil volume, such as a waste pile.
In the latter case, the mass-loading approach is more appropriate wherein the mass of particles in the
air is assumed to be derived solely from the contaminated soil. A default value of 100 micrograms per
16
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cubic meter is frequently assumed, although a site-specific measured long-term average value can be
used. Also, an enhancement factor is frequently used, where the contaminant is assumed to be more
concentrated on the small re-suspended particles compared to the bulk mass of the soil. Values of the
enhancement factor might vary from 1 to 5. Thus, the predicted concentration of a radionuclide above
the soil surface is:
Ca = K E M Cs where
Ca = Concentration of radionuclide in air, pCi per cubic meter;
K = Units-conversion factor, 1E-6 g per micro-g;
E = Enhancement factor, unitiess;
M = Mass loading, micro-g per cubic meter; and
Cs = Concentration of radionuclide in soil, pCi per g.
3.3.8 Uncertainty Analysis
The RAC notes that ORIA apparently intends to use only 1000 iterations of the Monte Carlo
simulation in its uncertainty analysis. While this number could well be sufficient for ORIA's purposes, it
might be wise to investigate convergence before limiting the target number of iterations.
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4. ISSUES BEYOND THE CHARGE
ORIA's approach to TENORM issues is comprehensive and, after incorporating the RAC
recommendations in response to the charge questions, will provide a reasonable estimate of the
occurrence and risks. Several issues beyond the charge merit consideration by ORIA.
4.1 Intended Scope of the TENORM Documents
The RAC was unclear about the intended scope of the TENORM documents. Under the
Executive Order 10831 and Reorganization Plan Number 3, EPA is charged with developing Federal
Guidance. Federal Guidance is defined as a set of guidelines developed by EPA for use by Federal
and State agencies responsible for protecting the public from the harmful effects of radiation. Federal
guidance helps protect both the general public and the people who work with and around radiation
every day. Technical Reports that provide current scientific and technical information for radiation dose
and risk assessment can be considered federal guidance. Since these guidance documents are not
regulations, they are not legally enforceable. Federal and State agencies have the authority to determine
the details of their own regulations within the scope of their authority.
As it is the EPA's goal to protect the public, the RAC generally supports a broader
interpretation not restricted by the interagency boundaries and recommends that ORIA include
products as well as wastes in the TENORM technical documents. While this recommendation
reaches into the realm of policy, not generally addressed by the RAC, several Members of the
Committee felt that it is important to raise it in the Advisory on TENORM. The RAC also
recommends that ORIA consider avoiding the emphasis on TENORM wastes. EPA has done a
notable job of promoting pollution prevention and encouraging people to "reduce, reuse, and recycle."
With sustainability as the goal, the newest industrial parks are designed for the byproducts of one
industry to directly flow to another industry as raw materials. Examples of TENORM materials that
can be considered "waste" to one industry, but "feed material" to another industry include 1 le(2)
material2, slag from rare earth mineral extraction, and sewage sludge. The 1 le(2) material is sold as
feed material for uranium processing. The sewage sludge is sold to farmers as a soil conditioner. The
slag from rare earth mineral extraction is sold as "ladle cover" for smelting, and then the smelting
industry slag is ground up and added to concrete in cinder blocks to add strength.
The U.S. Nuclear Regulatory Commission (NRC) Report Radiological Assessments for
Clearance of Equipment and Materials from Nuclear Facilities (referred to as NUREG 1640) (NRC,
The term "1 le(2) material" is used as shorthand for uranium or thorium mill tailings and refers to the section in the Atomic
Energy Act where they are defined. The specific definition is "the tailings or wastes produced by the extraction or concentration
of uranium or thorium from any ore processed primarily for its source material content."
18
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1999) discusses possible scenarios for the use of slag in Appendix J. These include the use of steel
industry slag in basement construction as an aggregate in the concrete block, the use of slag in a
roadbed, and the disposal of slag at a landfill. The RAC believes that the type of comprehensive
approach used for following radionuclides in NUREG 1640 is the approach necessary to give an
accurate picture of risk. Without commenting on the content of NUREG 1640, the approach used
followed radionuclides through various processes in products and in "wastes" while considering
exposures to workers and to the public.
Issue Paper #2 discusses TENORM "waste" and mentions that the report will focus on
TENORM from both overburden and evaporation ponds. The use of the term "waste" and the
suggested focus seem to imply that the full range of risks would not be assessed. The actual intent of
the report in this regard should be clarified. The public might gain a better appreciation of the
importance of TENORM relative to already regulated radioactive materials if the analysis included a
characterization and risk assessment of all sources of radiation associated with a given facility or
product. For an operating open-pit mine (and perhaps associated mill), for example, the analysis could
include the release of radon and soil borne materials by blasting, the loading and transport of ore and
overburden, any on-site milling and beneficiation, and releases of radon from stockpiled ore and
finished product.
The RAC notes that some of the non-waste sources may be relatively important. For example,
the radionuclides in coal-fired power plant emissions, which could be considered to be TENORM, may
well result in some risk. The radiological risks from coal-fired and nuclear power plants are about the
same, depending on the age and type of power plants, both coal-fired and nuclear (UNSCEAR, 1993).
Although the RAC realizes that ORIA's principal focus for TENORM is on assessing risks
prospectively in order to judge the need for prevention or remedial activities, this focus was not made
clear in the materials provided. The time frame and exposure conditions that are the focus of the risk
assessment of any TENORM source should be made clear in any document intended for use by the
public. The RAC further notes that the risk to an individual can depend on his or her past exposures as
well as future exposures. The projected risk for a lifetime of exposure for a person born today and
residing near the site may be different from that for a current resident who might have experienced
higher or lower exposures in the past than suggested by current conditions. The affected public will be
interested in risk estimates applicable to their own exposure histories and should be warned that the
prospective risk estimates provided in the TENORM documents may not be applicable to their cases.
4.2 Use of Existing Data from Other Programs Within EPA
ORIA should review the available data obtained by other program offices such as CERCLA
and the regional offices regarding TENORM sources, in particular, uranium mines. The data from
these sources could be useful in quantifying the extent of the problem. Environmental media
19
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concentration data and gamma exposure rate data gathered in support of site-specific risk assessments
could be used to validate the models for particular types of sites.
4.3 Background Evaluation for TENORM Sites
Any evaluation of background at TENORM sites should take into account not just average soil
background radionuclide concentrations but also background variability within localized areas.
Uranium mines, by necessity, are located in mineralized areas that may have un-mined outcrops of
relatively high grade ore and several different soil types with varying radionuclide concentrations. These
areas are representative of local background conditions and can contribute significantly to background
radiation doses.
4.4 Education and Risk Communication
In Issue Paper #1, page 10, ORIA proposes to promote and provide education and guidance
for safely and economically cleaning up and disposing of TENORM Wastes. ORIA should consider as
its first educational opportunity scientific societies such as the Conference on Radiation Control
Program Directors and the Health Physics Society. Consideration should be given to presentation of
papers at meetings and papers in society publications.
In the ORIA presentation to the RAC regarding the Uranium TENORM Report, it was pointed
out that of the 4,000 plus mines, approximately 1,000 are on Tribal lands. It is important that ORIA
communicate risk assessment plans with all of the affected tribes in advance of the study. Dedicated
efforts need to be developed to involve the tribes in providing input for the pathway calculations. It is
well known that Native Americans have some living habits and ingestion patterns that differ from other
American population groups.
The RAC supports ORIA's intent to make the TENORM documents useful to a broad
audience. The usefulness of the document will be limited if various parts of the risk are left out of the
risk assessment because they are regulated by different agencies to differing degrees. The audience will
be left with an inaccurate picture consisting of a sum of partial risks derived from different agency risk
assessments which are not designed to be aggregated.
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5. SPECIFIC COMMENTS BY COMMITTEE PARTICIPANTS
General: Several references may be useful in developing the TENORM technical reports,
specifically NCRP Report No. 118, "Radiation Protection in the Mineral Extraction Industry", and a
book written in the 1950s titled "Uranium Country".
Issue Paper #2, Pg 11, VII. B. Methodology and Techniques, 2nd paragraph: Mentions EIA
(Energy Information Agency of DOE) compiling reclamation cost information on uranium recovery
facilities. Presumably this includes side-stream extraction, and overlaps with U-milling. Is this to be
included in the report, or was it just mentioned in passing?
Issue Paper #3, Pg 5 para 1: States that "these distributions will not be meant to represent
actual or expected parameter value distributions." Why not?
Issue Paper #3, Pg ,5 Second to last sentence: "The maximum values will then be calculated
and returned to @RISK." This is not clear. Isn't this technique used to avoid the bias associated with
presenting maximum values? Aren't frequency distributions reported and then the user can see central
tendency as well as various percentiles?
Issue Paper #3, Dose and Risk Factors (pg 9, 3rd full paragraph): Ingestion and inhalation dose
conversion factors from FGR-11. Risk conversion factors from FGR-13. Isn't this using two different
generations of ICRP dosimetry?
Issue Paper #3: How will radon emanation rates be determined?
21
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APPENDIX A- GLOSSARY OF TERMS AND ACRONYMS
ATV
@RISK
Ca
CERCLA
Ci
Cs
CPG
DOE
E
E
EPA
g
1-129
ICRP
ISI
K
M
micro
MCLs
McroShield
NCRP
NIOSH
NORM
NRC
ORIA
P
All Terrain Vehicle
A multi-variance uncertainty model. This is the code that employs sampling
techniques to generate outputs as statistical distributions rather than single point
values
Concentration of radionuclide in air, pCi per cubic meter
Comprehensive Environmental Response and Liability Act
Curies (3.7xl010 disintegration per second)
Concentration of radionuclide in soil, pCi per g
Critical Population Group
U.S. Department of Energy
Enhancement factor, unitiess
Exponent (e.g. 1E-6 = 10'6)
U.S. Environmental Protection Agency (U.S. EPA, or "The Agency")
Gram
Iodine-129. As an unstable radioactive isotope of iodine. Iodine 129 is
produced naturally in the upper atmosphere and also produced in nuclear
explosions. In addition, iodine 129 is released at very low levels into the
environment from facilities that separate and reprocess nuclear reactor fuels,
and from waste storage facilities.
International Commission on Radiological Protection
Inter Systems, Inc.
Units-conversion factor, 1E-6 g per micro-g
Mass loading, micro-g per cubic meter
• ,[10"6] in combination with specific units
Maximum Contaminant Levels
The MicroShield model is a single pathway model designed to calculate
external gamma exposure rates from radiation sources of various sizes and
shapes (Grove 1996). The model utilizes either analytical expressions and
numerical integration to calculate the gamma exposure rate at a point near the
radiation source. MICROSHIELD has the capability to model 16 different
source and shield configurations, including point, line, plane, and disk sources,
rectangular slabs, cylinders, and spheres.
National Council on Radiation Protection and Measurements
National Institute of Occupational Safety and Health
Naturally-Occurring Radioactive Material
Nuclear Regulatory Commission
Office of Radiation and Indoor Air (U.S. EPA)
pico-, [10"12] in combination with specific units
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PRESTO Prediction of Radiological Effects due to ^hallow Trench Operations. A family
of codes developed to evaluate doses resulting from the disposal of low-level
radioactive waste. These codes include PRESTO-EPA-CPG (assesses annual
effective dose equivalents to a critical population group), PRESTO-EPA-
DEEP (assesses cumulative population health effects resulting from the disposal
of low-level waste using deep geologic repositories), PRESTO-EPA-BRC
(assesses cumulative population health effects to the general population residing
in the downstream regional basin as a result of the disposal of low-level waste
in an unregulated sanitary landfill),and PRESTO-EPA-POP (assesses
cumulative population health effects to the general population residing in the
downstream regional basin on a low-level waste site)
PRESTO-EPA-CLNCPG
The PRESTO-CLNCPG model (RAE 1999) was developed by EPA for
evaluating contaminated soil sites. The computer code is a modified and
extended version of the PRESTO-CPG model for low-level waste site
analyses. The model predicts the maximum annual committed effective dose to
a critical population group living on a contaminated soil site or a near surface
low-level radioactive waste disposal facility. The exposure pathways to the
critical population group include: Groundwater transport to a well, erosion and
runoff to surface water, external radiation, production of vegetables, milk, and
meat on contaminated soil, dust inhalation, Radon gas inhalation, inadvertent
ingestion of soil, and consumption offish.
PRESTO-EPA-CLNPOP
The computer code is a modified and extended version of the PRESTO-POP
model to include the onsite resident scenario.
RAC Radiation Advisory Committee (U. S. EPA/SAB/RAC)
RESRAD Residual Radioactive Materials Guidelines (The DOE Model). This is a
computer code developed by DOE to implement its guidelines for deriving
guidelines for allowable concentrations of residual radioactive material in soil.
Rn Radon, as an element or as an isotope of thorium or uranium alpha-decay
chains (e.g., 219Rn, 220Rn, 222 Rn)
SAB Science Advisory Board (U. S. EPA)
Tc-99 Technetium-99. Technetium-99 is predominantly an artificially produced,
silver-gray, radioactive metal, occurring naturally only in very small amounts in
the earth's crust. Tc-99 was first obtained from molybdenum but is also
produced as a nuclear reactor fission product of uranium and plutonium.
TENORM Technologically Enhanced Naturally Occurring Radioactive Materials
Tritium a form of hydrogen that is radioactive, and like hydrogen it reacts with oxygen to form
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water. Tritium is produced naturally in the upper atmosphere when cosmic rays strike
air molecules. Tritium can also be produced by man during nuclear weapon explosions,
in reactors intended to produce tritium for nuclear weapons, and by reactors producing
electricity.
Th Thorium, as an element or as an isotope (e.g., 228Th, 230Th, 232Th, 234Th)
U Uranium, as an element or as an isotope (e.g., 234U, 235U, 238U)
Uncertainty Lack of knowledge about the true value of a parameter for a particular set of
conditions
Uncertainty Analysis Refers to the study of the uncertainty of the model outputs as a function of
parameter and data uncertainties
UNSCEAR United Nations Scientific C ommittee on the Effects of Atomic Radiation
Variability Variation from site to site or from person to person
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REFERENCES
Chen, S.Y., LePoire, D.J., Arnish, J.A., Faillace, E., Kamboj, S.K., and B. Whany. 1998.
MILDOS-AREA User's Guide MILDOS-AREA User's Environmental Assessment Division,
Argonne National Laboratory, Argonne, IL (http://web.ead.anl.gov/mildos/usersguide.pdf)
EPA. (U.S. Environmental Protection Agency, Office of Radiation and Indoor Air). 2000a. Issue
Paper #1 - Proposed EPA Approach to TENORM ). U.S. Environmental Protection Agency,
Washington, DC.
EPA (U.S. Environmental Protection Agency, Office of Radiation and Indoor Air). 2000b. Issue
Paper #2 - Proposed Outline for Uranium TENORM Report. U.S. Environmental Protection
Agency, Washington, DC.
EPA (U.S. Environmental Protection Agency, Office of Radiation and Indoor Air). 2000c. Issue
Paper #3 - Proposed TENORM Risk Assessment Methodology. U.S. Environmental
Protection Agency, Washington, DC.
EPA (U.S. Environmental Protection Agency, Office of Air and Radiation). 1998. Health Risks from
Low-Level Environmental Exposure to Radionuclides, Federal Guidance Report No. 13 - Part
1, Interim Version (EPA 402-R-97-014).
Grove Engineering. 1996. MICROSHTET J). Version 5, User's Manual. Grove Engineering, Rockville
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iu/.
ISI (Inter Systems, Inc). 1983. PRESTO-EPA Quality Assurance Audit. A report generated
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Ivanov, V. K.; Maksioutov, M. A., Chekin, S. Yu.; Kruglova, Z. G; Petrov, A. V., and A.F. Tsyb.
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Mills, W.B., Lew, C.S, and C.Y. Hung. 1999. Sensitivity of Concentration and Risk Predictions in the
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NAS/NRC (National Academy of Science/National Research Council). 1999. Evaluation of
Guidelines for Exposures to Technologically Enhanced Naturally Occurring Radioactive
Materials. Report of the National Research Council. National Academy Press. Washington,
DC.
NRC (U.S. Nuclear Regulatory Commission). 1999. Radiological Assessments for Clearance of
Equipment and Materials from Nuclear Facilities (NUREG-1640 Vol. 1 &Vol. 2) Draft Report
for Comment, March 1999.
NCRP (National Council on Radiation Protection and Measurements). 1993. Radiation Protection in
the Mineral Extraction Industry. Bethesda, MD, USA.
Rogers, V.C. 1997. Approaches for Modeling Components of Performance Assessment.
Presentation at the US Department of Energy Low-Level Radioactive Waste Management
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SAB (Science Advisory Board). 1999. Radiation Advisory Committee (RAC). Review of Health
Risks From Low-Level Environmental Exposures to Radionuclides (FGR-13 REPORT). EPA-
SAB-RAC-99-009.
SAB (Science Advisory Board). 1994. SAB Radiation Advisory Committee (RAC). Review of
Diffuse NORM Draft Scoping Document. EPA-SAB-RAC-94-013.
Shimizu, Y., Pierce, D. A., Preston, D. L., and K. Mabuchi. 1999. Studies of the mortality of atomic
bomb survivors. Report 12, Part II. Noncancer mortality: 1950-1990. Radial. Res.
152:374-389.
UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation). 1993. Sources
and effects of ionizing radiation. UNSCEAR 1993 report to the General Assembly, with
scientific annexes. United Nations, New York, NY.
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