Ionizing Radiation Exposure of the Population of the United States, Report 93

87 Pages·1987·3.83 MB·english

by  National Council on Radiation Protection and Measurements

NCRP REPORT No. 93
IONIZING RADIATION
EXPOSURE OF THE
POPULATION OF THE
UNITED STATES
Recommendations of the
NATIONAL COUNCIL ON RADIATION
PROTECTION AND MEASUREMENTS
Issued September 1,1987
First Reprinting April 15,1998
National Council on Radiation Protection and Measurements
I
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Library of Congress Catploging-in-PublicationD ata
National Council on Radiation Protection and Measurements.
Ionizing radiation exposure of the population of the United States.
(NCRP report ;n o. 93)
Bibilography: p.
Includes index.
1. Ionizing radiation-Dosage. 2. Ionizing radiation-Environmental aspects-
United States. 3. Health risk assessment-United States. I. Title. II. Series. fDNLM:
1. Environmental Exposure. 2. Radiation Injuries-prevention & control. 3. Radiation
Monitoring. WN 650 N279il
RA569.N353 1987a 363.1'79 87-22062
ISBN 0-913392-91-X
Copyright O National Council on Radiation
Protection and Measurements 1987
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Preface
The NCRP has recognized for some time the need for a clear
assessment of the magnitude of the doses from various sources of
radiation to which the population of the U.S. is exposed In anticipa-
tion of the need to gather basic data for input into this process five
assessment committees, each addressing a different source category,
were established in 1971. NCRP reports assessing exposures from
natural background and from consumer products were produced
(NCRP 1975, 1977), but no attempt was made to develop a compre-
hensive account of all sources of exposure.
In 1985, the NCRP reconsidered its overall effort in this area and,
with the further support and stimulation of the Committee on Inter-
agency Radiation Research and Policy Coordination (Office of Science
and Technology Policy, Executive Office of the President of the United
States), undertook to evaluate the exposure of the U.S. population
from all sources.
Six organizational groups were constituted or reconstituted to ad-
dress different phases of the task and the results of their work are
summarized in this document, which describes the exposure of the
U.S. population from all known sources.
The six organizational groups and their members are:
iii
iv / PREFACE
Scientific Committee 28- Scientific Committee 43-
Radiation Exposure from Comurner Natural Background Radiation
Products J.H. Harley, Chru'rman
D.W. Moeller, Chairman RB. Holtzman
R.J. Guimond W.M.L owder
J.W.N. Hickey D.P. Meyerhof
E. Miller A.B. Tanner
G.D. Schmidt N.A. Wogman
Consultants:
B.S. Pasternack
J.K. Soldat
J.A. Young
Scientific Committee 44- Scientific Committee 45-
Radiation Associated with Medical Radiation Received by Radiation
Examinations Employees
RD. Moseley, Jr.7. Chairnun (1976- D.E.B arber, Chairman
1987) B.G. Brooks
F. A. Mettler. Jr., Chairman (1987- L.H. Lanzl
J.S. Acarese R.E. Shore
W.W. Burr, Jr. P.S. Stansbury
R.O. Gorson R.A. Wynveen
S. Marks
A. Raventos
M. Rosenstein
E.L. Saenger
B. Shleien
Advisors:
D.L. Abernathy
R.E. Bunge
L.A. Selke
Consultant:
J.G. Kereiakes
scientific Committee 64, Scientific Committee 64, Special
Task Group 5*- Group*-
Public Exposure from Nuclear Power MisceUaneow Environmental Sources
B. Kahn, Chair- W.E. Kreger, Co-Chairman
M.J. BelJ W.A. Mills, Co-Chairman
ILL. Blanchard
E.F. Branagan, Jr.
K. Cowser
K.F. Eckerman
J.M. Hardin
R.E. Luna
E.Y.S. Shum
C. Wills
J.F. Wing
t Deceased.
*Subgroups of Scientific Committee 64 on Radionuclides in the Environment; Chair-
man, M.W. Carter, M. Eisenbud, J.W. Healy, W.E. Kreger, W.A. Mills, J.N.
Stannard, J.E. Till and M.E. Wrenn
PREFACE / v
These groups, except for the Special Group on Miscellaneous En-
vironmental Sources, are in the course of producing separate NCRP
reports.
This summary report was prepared by the NCRP's Scientific Com-
mittee 48, Assessment of Exposures of the Population Contributed by
Various Sources. Serving on Scientific Committee 48 during the prep-
aration of this report were:
W.K. Sinclair, Chairman
National Council on Radiation Protection
and Measurements
Bethesda, Maryland
S.J. Adelstein J.H. Harley
Haward Medical School Hoboken, New Jersey
Boston, Maesachusetta
D.W. Moeller
M.W. Carter Haward School of Public Health
Georgia Institute of Technology Boston, Massachusetts
Atlanta, Georgia
NCRP Secretariat-T.M. Koval
The NCRP is grateful to all who not only contributed their expertise
in developing the contents of these reports but also made extraordinary
efforts in managing their schedules of work to make this coordinated
comprehensive report possible. Dr. F.A. Mettler, Jr. and Dr. D.E.
Barber made important contributions to this text.
Tom Koval served as the NCRP staff member providing support for
all of these organizational groups.
The International System of Units (SI) is used in this report
followed by conventional units in parentheses in accordance with the
procedure set forth in NCRP Report No. 82, SI Units in Radiation
Protection and Measurements.
Warren K. Sinclair
President, NCRP
Bethesda, Maryland
11 June 1987
Contents
.
1 Introduction
1.1 Sources of Population Exposure ...................
1.2 Earlier Surveys .................................
1.3 Quantities and Units .............................
1.4 The Present Report ..............................
.
2 Public Radiation Exposure from Natural Background
2.1 Introduction ....................................
2.2 Sources of Exposure .............................
2.2.1 Naturally Occurring Radionuclides ..........
2.2.2 External Radiation ........................
2.2.3 Radionuclides in the Body .................
2.3 Exposure Estimates ..............................
2.3.1 Cosmic Radiation .........................
2.3.2 Terrestrial Gamma Radiation ...............
2.3.3 Cosmogenic Radionuclides .................
2.3.4 Inhaled Radionuclides .....................
2.3.5 Radionuclides in the Body .................
2.3.6 Total Exposure from Natural Background ....
2.4 Recommendations ...............................
.
3 Occupational Exposure
3.1 Introduction ....................................
3.2 Sources of Data and Estimates ....................
3.3 Special Considerations ...........................
3.4 Discussion ......................................
.
4 Public Radiation Exposure from Nuclear 'Power
Generation
4.1 Introduction ....................................
4.2 Sources of Data .................................
4.3 Special Considerations ...........................
4.4 Estimates and Discussion .........................
4.5 Comments ......................................
.
5 Public Radiation Exposure from Consumer Products
5.1 Introduction ...................................
5.2 Sources of Data and Estimates ....................
5.3 Special Considerations ..........................
vii
viii / CONTENTS
5.4 Recommendations ...............................
.
6 Public Radiation Exposure from Miscellaneous
Environmental Sources
6.1 Introduction ....................................
6.2 SourcesofData .................................
6.3 Special Considerations ...........................
6.4 Estimates and Discussion .........................
6.5 Fallout from Nuclear Weapons Testing .............
6.6 Recommendations ...............................
.
7 Public Radiation Exposure from Medical Diagnosis
and Therapy
7.1 Introduction ....................................
7.2 Sources of Data for Diagnosis .....................
7.3 Special Considerations ...........................
7.4 Estimates and Discussion .........................
7.5 Recommendations ...............................
. 7.6 Radiation Therapy ..............................
8 Summary and Conclusions
8.1 Introduction ....................................
8.2 The Exposure of the U.S . Population to All Sources . .
8.3 The Most Significant Exposures ...................
8.4 Special Considerations ...........................
8.5 Recommendations ...............................
8.5.1 Recommendations for Dose Reduction .......
8.5.2 Recommendations for Improved Data in the
Future .................................
8.5.2.1 Natural Background ..............
8.5.2.2 Occupational ....................
8.5.2.3 Nuclear Fuel Cycle ...............
8.5.2.4 Consumer Products ...............
8.5.2.5 Miscellaneous Environmental
Sources .......................
8.5.2.6 Medical Sources ..................
8.6 Conclusions ....................................
.
Appendix A Glossary ..................................
References ............................................
The NCRP .............................................
NCRP Publications ......................................
Index .................................................
1. Introduction
1.1 Sources of Population Exposure
All members of the public in the United States are inevitably
exposed to sources of ionizing radiation, some to a wide variety of such
sources, others to only a few. The sources involved are of three general
types, those of natural origin, unperturbed by human activities, those
of natural origin but affected by human activities (termed enhanced
natural sources), and man-made sources.
Natural sources include cosmic radiation from outer space, terres-
trial radiation from natural radioactive sources in the ground, radia-
tions from radionuclides naturally present in the body and inhaled
and ingested radionuclides of natural origin. Each of these natural
sources has certain characteristics which lead to varying human ex-
posures depending on locality and other special circumstances. When
these exposures are substantially above the average they are referred
to as "elevated."
Enhanced natural sources include those for which human exposures
have been increased as a result of man's actions, deliberate or other-
wise. For example, air travel, especially at very high altitudes, increases
the exposure to cosmic radiation, whereas movement of radionuclides
on the ground, as in phosphate mining, can increase the terrestrial
component to persons living in houses built on phosphate and other
waste landfills. Radon exposures indoors might be considered, in some
instances at least, to be due to elevated natural levels and also to be
"enhanced natural" since the exposure can be increased by the char-
acteristics of the home. In a sense also, all the operations of the nuclear
fuel cycle, starting with mining, could be considered to be enhanced
exposures from natural materials but these are generally included with
"man-maden exposures.
A variety of exposures results from man-made materials and devices,
e.g., radiopharmaceuticals and x rays in medicine, and consumer
products containing radioactive materials such as some smoke detec-
tors or static eliminators. Exposures may also result from episodic
events due to man's activities, such as atmospheric nuclear weapons
testing, accidents in nuclear power plants, etc.
Although some previous attempts have been made to determine the
dose from all sources (as noted below), none of these has been fully
1
2 / 1. INTRODUCTION
comprehensive for the United States. It is therefore timely to make as
accurate an assessment as possible of the overall exposure of the U.S.
population from all sources of ionizing radiation. It is convenient to
categorize these sources according to the origin of the exposure,
namely: natural radiation, occupational, the nuclear fuel cycle, con-
sumer products, miscellaneous environmental sources connected with
human activities, and medical diagnosis and therapy. Unfortunately,
there are limitations in the accuracy of the data available in each of
these categories, which will become clear in the discussion below.
Nevertheless, this Report provides a comprehensive account of the
exposure of members of the U.S. public to all sources of ionizing
radiation.
1.2 Earlier Surveys
Selected surveys of one or more sources of radiation, especially
medical, have been made from time to time but few of these have
attempted to be comprehensive. Furthermore, assessment activities at
the international level, as exemplified by the earlier reports of the
United Nations Scientific Committee on the Effects of Atomic Radia-
tion (UNSCEAR) (UNSCEAR, 1958), and by joint groups of the
International Commission on Radiological Protection (ICRP) and the
International Commission on Radiation Units and Measurements
(ICRU) (ICRP-ICRU, 1957, 1961) on medical exposure, have tended
to emphasize global considerations rather than assessments of popu-
lation exposure in individual countries. However, the UNSCEAR
reports, which continue to provide global assessments of population
exposures from a variety of sources, inevitably rely, to a substantial
degree, on well-documented critical assessments of exposures at the
national level (UNSCEAR, 1982).
One early assessment of the exposure of the population in the U.S.
was made by Moeller, Terrill, and Ingraham (1953). This pioneering
report drew attention to natural background radiation and to medical
diagnostic radiation. The former was estimated to result in an exposure
of about nine roentgens in a 70-year lifetime and for the latter, the
average annual dose to a limited region of the body was estimated to
be about two roentgens to a "large portion" of the U.S. population.
Other less important sources treated in that report included medical
therapy, dental x rays, x rays in industry and research, radioisotopes
in medicine, radium in luminous paints, static eliminators, the ship-
ping of radioactive materials, nuclear reactors, and particle accelera-
tors. It was noted that it was not possible to reach definitive conclu-
1.2 EARLIER SURVEYS / 3
sions on the magnitude of the radiological health problem occasioned
by these sources of ionizing radiation because of the extremely frag-
mentary nature of much of the data
In 1960 the Federal Radiation Council published a document which
contained a section on sources of radiation exposure (FRC, 1960).
This report concluded that the exposure of human beings from natural
sources led to average annual dose equivalents to bone marrow, gonads
and soft tissue of between 0.8 mSv (80 mrem) and 1.7 mSv (170 mrem),
while from medical sources the annual genetically significant dose
(GSD) was from 0.8 mSv (80 mrem) to 2.8 mSv (280 mrem) and the
mean bone marrow dose was of the same order. Weapons testing
fallout was identified as an important contributor, resulting in an
average genetically significant dose of 0.53 mSv (63 mrem) over the
following 30 years if atmospheric nuclear testing were not resumed
after the cessation in 1958, but eight times this dose if atmospheric
testing were resumed and continued at the same rate as in the previous
five years. The mean bone marrow dose over 70 years would be 3.3
mSv (330 mrem) and 26.5 mSv (2,650 mrem), respectively, for these
two circumstances. The nuclear fuel cycle was not believed to release
radioactivity sufficient to cause a significant cnntribution to the pop-
ulation dose.
A new effort was initiated by the Federal Radiation Council in 1970,
and resulted in a report being produced by the Environmental Protec-
tion Agency (EPA, 1972) on the exposure of the U.S. population for
the years 1960-1970 with predictions to the year 2000. Only environ-
mental sources were considered, and the average annual natural back-
ground exposure was found to be about 1.3 mSv (130 mrem) in 1960,
while fallout from earlier atmospheric tests of nuclear devices contrib-
uted an additional ten percent. All other sources were minor. The
annual dose from fallout was expected to decline to about three percent
of the natural background by 1970 and to stay at about that level until
the year 2000.
A few years later the EPA again reviewed the sources of ionizing
radiation exposure to the population (EPA, 1977). The conclusions of
this report were that the four major source categories contributing to
the collective exposure of the United States population to ionizing
radiation were environmental radiation, medical and dental radiation,
the application of radiopharmaceuticals in medicine, and technologi-
cally enhanced natural radiation. However, the largest doses on an
individual basis were identified as those from technologically enhanced
natural radiation, medical radiation, environmental radiation, con-
sumer products, occupational and industrial operations, and federal
nuclear facilities. A particular source responsible for high individual
doses in the category of technologically enhanced natural radiation