Comparative Dosimetry of Radon in Mines and Homes

Panel on Dosimetric Assumptions Affecting the Application of Radon Risk Estimates

Board on Radiation Effects Research

Commission on Life Sciences

National Research Council

NATIONAL ACADEMY PRESS
Washington, D.C.
1991



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page R1
Comparative Dosimetry of Radon in Mines and Homes Comparative Dosimetry of Radon in Mines and Homes Panel on Dosimetric Assumptions Affecting the Application of Radon Risk Estimates Board on Radiation Effects Research Commission on Life Sciences National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1991

OCR for page R1
Comparative Dosimetry of Radon in Mines and Homes NATIONAL ACADEMY PRESS 2101 Constitution Avenue, N.W. Washington, D.C. 20418 NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the panel responsible for the report were chosen for their special competences and with regard for appropriate balance. This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. This project was prepared under Grant No. X-816115-01-0 between the National Academy of Sciences and the U.S. Environmental Protection Agency. Library of Congress Cataloging-in-Publication Data Comparative dosimetry of radon in mines and homes / Panel on Dosimetric Assumptions Affecting the Application of Radon Risk Estimates, Board on Radiation Effects Research, Commission on Life Sciences, National Research Council. p. cm. Includes bibliographical references and index. ISBN 0-309-04484-7 1. Radon—Measurement. 2. Radiation dosimetry. 3. Indoor air pollution. 4. Mine safety. I. National Research Council. Panel on Dosimetric Assumptions Affecting the Application of Radon Risk Estimates. RA1247.R33C66 1991 628.5′35—dc20 91-10157 CIP Cover: Mine photograph by Samet. Copyright © 1991 by the National Academy of Sciences. No part of this book may be reproduced by any mechanical, photographic, or electronic process, or in the form of a phonographic recording, nor may it be stored in a retrieval system, transmitted, or otherwise copied for public or private use, without written permission from the publisher, except for the purposes of official use by the U.S. government. Printed in the United States of America

OCR for page R1
Comparative Dosimetry of Radon in Mines and Homes PANEL ON DOSIMETRIC ASSUMPTIONS AFFECTING THE APPLICATION ON RADON RISK ESTIMATES JONATHAN M. SAMET (Chairman), University of New Mexico, Albuquerque, New Mexico ROY E. ALBERT, University of Cincinnati, Cincinnati, Ohio JOSEPH D. BRAIN, Harvard School of Public Health, Boston, Massachusetts RAYMOND A. GUILMETTE, Inhalation Toxicology Research Institute, Albuquerque, New Mexico PHILIP K. HOPKE, Clarkson University, Potsdam, New York ANTHONY C. JAMES, Battelle Pacific Northwest Laboratories, Richland, Washington DAVID G. KAUFMAN, University of North Carolina, Chapel Hill, North Carolina Staff RAYMOND D. COOPER, Study Director WILLIAM H ELLETT, Senior Program Officer RICHARD E. MORRIS, Editor, National Academy Press Sponsor's Project Officers NEAL S. NELSON, U. S. Environmental Protection Agency ANITA L. SCHMIDT, U. S. Environmental Protection Agency

OCR for page R1
Comparative Dosimetry of Radon in Mines and Homes BOARD ON RADIATION EFFECTS RESEARCH MORTIMER L. MENDELSOHN (Chairman), Lawrence Livermore National Laboratory, Livermore, California ERIC J. HALL, Columbia University, New York, New York DANIEL L. HARTL, Washington University School of Medicine, St. Louis, Missouri* LEONARD S. LERMAN, Massachusetts Institute of Technology, Cambridge, Massachusetts FREDERICK MOSTELLER, professor emeritus, Harvard University, Cambridge, Massachusetts JOSEPH E. RALL, National Institutes of Health, Bethesda, Maryland WARREN K. SINCLAIR, National Council on Radiation Protection and Measurements, Bethesda, Maryland THOMAS S. TENFORDE, Battelle Pacific Northwest Laboratories, Richland, Washington ARTHUR C. UPTON, New York University Medical Center, New York, New York Ex Officio BRUCE M. ALBERTS, University of California, San Francisco, California Staff CHARLES W. EDINGTON, Director RAYMOND D. COOPER, Senior Program Officer WILLIAM H ELLETT, Senior Program Officer CATHERINE S. BERKLEY, Administrative Associate DORIS E. TAYLOR, Administrative Assistant *   Resigned October 1990.

OCR for page R1
Comparative Dosimetry of Radon in Mines and Homes COMMISSION ON LIFE SCIENCES BRUCE M. ALBERTS (Chairman), University of California, San Francisco, California BRUCE N. AMES, University of California, Berkeley, California FRANCISCO J. AYALA, University of California, Irvine, California J. MICHAEL BISHOP, University of California Medical Center, San Francisco, California MICHAEL T. CLEGG, University of California, Riverside, California GLENN A. CROSBY, Washington State University, Pullman, Washington FREEMAN J. DYSON, Institute for Advanced Study, Princeton, New Jersey LEROY E. HOOD, California Institute of Technology, Pasadena, California DONALD E HORNIG, Harvard School of Public Health, Boston, Massachusetts MARIAN E. KOSHLAND, University of California, Berkeley, California RICHARD E. LENSKI, University of California, Irvine, California STEVEN P. PAKES, University of Texas, Dallas, Texas EMIL A. PFITZER, Hoffmann-LaRoche, Inc., Nutley, New Jersey THOMAS D. POLLARD, Johns Hopkins Medical School, Baltimore, Maryland JOSEPH E. RALL, National Institutes of Health, Bethesda, Maryland RICHARD D. REMINGTON, University of Iowa, Iowa City, Iowa PAUL G. RISSER, University of New Mexico, Albuquerque, New Mexico HAROLD M. SCHMECK, JR., Armonk, New York RICHARD B. SETLOW, Brookhaven National Laboratory, Upton, New York CARLA J. SHATZ, Stanford University School of Medicine, Stanford, California TORSTEN N. WIESEL, Rockefeller University, New York, New York JOHN E. BURRIS, Executive Director

OCR for page R1
Comparative Dosimetry of Radon in Mines and Homes The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Frank Press is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Robert M. White is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Samuel O. Thier is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Frank Press and Dr. Robert M. White are chairman and vice chairman, respectively, of the National Research Council.

OCR for page R1
Comparative Dosimetry of Radon in Mines and Homes Preface Among the recommendations in the Biological Effects of Ionizing Radiation (BEIR) IV report was a statement on the need for further research and analysis on uncertainties in applying the lung cancer risks characterized for underground miners to people in their homes. Specifically, the BEIR IV committee stated: Further studies of dosimetric modeling in the indoor environment and in mines are necessary to determine the comparability of risks per WLM [working level month] in domestic environments and underground mines. Because of the importance to the public of the risks of radon exposure in homes and schools, the U.S. Environmental Protection Agency (EPA) asked the National Research Council (NRC) to initiate a study of the dosimetric considerations affecting the applications of risk estimates, based on studies of miners, to the general population. EPA asked that a panel be assembled to investigate the differences between underground miners and members of the general public in the doses they receive per unit exposure due to inhaled radon progeny. CHARGE TO THE COMMITTEE The committee was asked to do the following: Review the basis of current dosimetric models for inhaled radon progeny, paying particular attention to the assumptions that are a part of these models and the experimental data that are used to verify them. Compare these models with lung deposition models developed for nonradioactive pollutants.

OCR for page R1
Comparative Dosimetry of Radon in Mines and Homes The committee's study should be directed toward estimating the dose per unit exposure and not exposure levels that may exist in homes or in mines. Examine the experimental data base for characterizing aerosols and radon progeny concentrations in underground mines and home environments, taking into account the possible changes in these environments that have occurred in the last 40 years. Examine differences in breathing patterns of working miners and individuals in the mining environment, taking into account the level of physical activity, sex, age, and so on. Determine to what extent the relevant physiological parameters are based on experimentally derived values, with particular reference to underground miners and other manual laborers doing similar work. Determine which parameters, such as bronchial generations and tissue depth, are most useful for characterizing a dose-risk relationship for radiogenic lung cancers. With the foregoing information, estimate the ratio of the dose per working level month to an underground miner to the dose per working level month to people of different ages and sexes in a variety of domestic environments. To the extent possible, characterize the uncertainties in these estimates. Define research needs, including judgments on the relative importance of the various parameters needed to calculate the dose from radon progeny. Present the results in an NRC report. ORGANIZATION OF THE STUDY The NRC established a committee of seven members with expertise in radon risks, radon dosimetry, aerosol physics, respiratory physiology, carcinogenesis, and lung modeling to carry out the study. General guidance was provided by the Board on Radiation Effects Research of the Commission on Life Sciences. The committee held five meetings, four in Washington, D.C., and one in Woods Hole, Massachusetts. During an early meeting, the panel invited several outside experts to present the results of their research on lung modeling and lung cancer to ensure that a broad cross-section of the scientific community had provided input. The study was divided into two parts. The first part was the determination of the differences in atmospheres, breathing rates, and other factors between mines and miners and homes and the people who live in them. The second part included the application of a new lung model to these factors in order to determine a ratio of dose per unit exposure in homes and mines. The report covers these areas and a discussion of other considerations affecting the risk of lung cancer from radon exposure.

OCR for page R1
Comparative Dosimetry of Radon in Mines and Homes ORGANIZATION OF THE REPORT The report is arranged so that the major elements of the committee's analysis and conclusions are described first, followed by a number of background chapters that include technical details of the data and models used and the reasons for choosing the models used. After a summary of the committee's findings and recommendations for further research and analysis, the main body of the report begins with an introduction to the dosimetry of radon (Chapter 1) and how this differs in mines and homes (Chapter 2). A description of the data used by the committee on exposures of miners and people in their homes follows. Chapter 3, the main element of the report, answers the questions posed to the committee. It includes the major results of the committee's analysis. The main body of the report concludes with a description in Chapter 4 of factors other than those involved in dosimetry, that are important in determining risk. Five background chapters describe in greater detail many of the elements that went into the first part of the report. Chapter 5 is a general description of radon dosimetry and the lung models that were used. Chapter 6 discusses aerosols in homes and mines, their diffusion and growth, and the means by which they are measured. Oral and nasal breathing and the deposition and clearance of particles in the lung are described in Chapter 7, and Chapter 8 discusses the different types of lung cancers and the cells of origin that are the targets for the dosimetry. Finally, Chapter 9 describes the specific lung model used by the committee and the calculations that led to the results given in the first part of the report. ACKNOWLEDGMENTS The panel acknowledges with thanks the scientific input provided by a number of invited participants. These included Dr. Geno Saccomanno, who described his studies on lung pathology; Dr. Naomi Harley, who discussed radon dosimetry; Dr. Elizabeth McDowell, who described the types of lung cells at risk; and Dr. David Swift, who spoke on the fate of inhaled radon and its progeny. All of these scientists gave freely of their data and findings and were of great help in clarifying some of the scientific issues under study. The lung model used by the panel was developed, in part, by the task group of the International Commission on Radiological Protection (ICRP). The committee would like to thank the ICRP task group and, particularly, M. J. Egan and W. Nixon, who developed the theory for aerosol deposition in the lung upon which the model is based. The committee thanks Doris Taylor for her work on several drafts of this manuscript and for her help in making arrangements for committee meetings and travel. Finally, thanks are due to the radon research programs sponsored by the U.S. government. Many of the data used by the committee were developed by the radon research program of the U.S. Department of Energy.

OCR for page R1
Comparative Dosimetry of Radon in Mines and Homes This page in the original is blank.

OCR for page R1
Comparative Dosimetry of Radon in Mines and Homes Contents     Summary and Recommendations   1 1   Introduction   9 2   Assessment of Exposure to the Decay Products of 222Rn in Mines and Homes   20 3   Extrapolation of Doses and Risk per Unit Exposure from Mines to Homes   31 4   Other Considerations   52 5   Dosimetry and Dosimetric Models for Inhaled Radon and Progeny   60 6   Aerosols in Homes and Mines   90 7   Breathing, Deposition, and Clearance   137 8   Cells of Origin for Lung Cancer   166 9   The Committee's Dosimetric Model for Radon and Thoron Progeny   194     Index   239

OCR for page R1
Comparative Dosimetry of Radon in Mines and Homes This page in the original is blank.