HEREDITARY EFFECTS OF RADIATION United Nations Scientific Committee on the Effects of Atomic Radiation UNSCEAR 2001 Report to the General Assembly, with Scientific Annex UNITED NATIONS HEREDITARY EFFECTS OF RADIATION United Nations Scientific Committee on the Effects of Atomic Radiation UNSCEAR 2001 Report to the General Assembly, with Scientific Annex UNITED NATIONS New York, 2001 NOTE The report of the Committee without its scientific annex appears as Official Records of the General Assembly. Fifty-sixth Session, Supplement No. 46 (N56146). The designation employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the pad of the Secretariat of the United Nationsconcerning the legal status of any country, temtory, city orarea, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The country names used in this document are, In most cases, those that were in use at the time the data were collected or the text prepared. In othercases, however, the names have been updated, where this was posslble and appropriate, to reflect political changes. UNITED NATIONS PUBLICATION Sales No. E.O1 .IX.2 ISBN 92-1-1 42244-2 Report of the United Nations Scientific Committee on the Effects of Atomic Radiation to the General Assembly 1. During the past few years, the United Nations 4. The Committee wishes to acknowledge the assistance Scientific Committee on the Effects of Atomic Radiation1 of the consultant, K. Sankaranarayanan, in the preparation has undertaken broad reviews of the sources and effects of of the scientific annex and the advice of the international ionizing radiation. Estimates of the carcinogenic risk from experts, S. Abrahamson, J.F. Crow, C. Deniston, U.H. exposures to ionizing radiation were presented in the Elhing, V.A. McKusick, W.R. Lee, M.F. Lyon, K.G. UNSCEAR 2000 Report2. In its 2001 Report, the Lüning, W.J. Schull and R.C. Woodruff, whose Committee has completed a comprehensive review of the independent review was sought by the Committee in its risks to offspring (hereditary risks) following parental deliberations. exposure to radiation. For the first time, the review included an evaluation of those diseases which have both 5. The sessions of the Committee held during the period hereditary and environmental components, the so-called under review were attended by observers from the World multifactorial diseases. The major finding is that the total Health Organization, the International Atomic Energy hereditary risk is 0.30.5 per cent per gray to the first Agency, the International Commission on Radiological generation following radiation. This is less than one tenth Protection and the International Commission on Radiation of the risk of fatal carcinogenesis following irradiation Units and Measurements. The Committee wishes to presented in the UNSCEAR 2000 Report. acknowledge their contributions to the discussions. 2. The present report and its scientific annex were 6. Radiation exposure has never been demonstrated to prepared between the forty-fourth and fiftieth sessions of cause hereditary effects in human populations. The absence the Committee. The following members of the Committee of observable effects in children of survivors of the atomic served as Chairman, Vice-Chairman and Rapporteur, bombings in Japan, one of the largest study populations, respectively, at those sessions: forty-fourth and forty-fifth indicates that moderate acute radiation exposures of even a sessions: L. Pinillos-Ashton (Peru), A. Kaul (Germany) and relatively large human population must have little impact. G. Bengtsson (Sweden); forty-sixth and forty-seventh However, experimental studies in plants and animals have sessions: A. Kaul (Germany), L.-E. Holm (Sweden) and J. clearly demonstrated that radiation can induce hereditary Lipsztein (Brazil); forty-eighth and forty-ninth sessions: effects. Humans are unlikely to be an exception in that L.-E. Holm (Sweden), J. Lipsztein (Brazil) and Y. Sasaki regard. (Japan); and fiftieth session: J. Lipsztein (Brazil), Y. Sasaki (Japan) and R. Chatterjee (Canada). The names of members 7. The Committee has concluded that a sounder basis of national delegations who attended the forty-fourth to now exists for estimating the hereditary risks of radiation fiftieth sessions of the Committee as members of national exposure. Advances in molecular genetics are contributing delegations are listed in the appendix to the present report. to improved understanding of the structural and functional changes in genes that underlie hereditary diseases. Gains 3. In approving the present report, the Committee have also been made in evaluating the risk of multifactorial applied its scientific judgement to the material it reviewed diseases such as coronary heart disease, diabetes and and took care to maintain an independent and neutral essential hypertension. Those diseases affect a large position in reaching its conclusions. Following established proportion of the population, occur throughout life, have practice, only the main text of the report is submitted to the varying severity and are affected by both genetic and General Assembly. environmental factors. 2 REPORT TO THE GENERAL ASSEMBLY 8. The Committee uses the doubling-dose method, which cases per gray per one million progeny; this constitutes 0.4 is based on equilibrium theory, for hereditary risk to 0.6 per cent of the baseline frequency of those disorders estimation. The doubling dose is the amount of radiation in the human population. required to produce the same number of mutations as occur spontaneously in one generation of the population. The 10. At its fiftieth session, held in Vienna from 23 to 27 reciprocal of the doubling dose is the relative mutation risk April 2001, the Committee decided on its new programme per unit dose. A high doubling dose implies a low relative of work. The Committee will gather new data on radiation mutation risk, and vice versa. The risk due to radiation is exposures from natural, man-made and occupational quantified as the number of additional cases of genetic sources; extend its evaluation of medical exposures, disease, over and above the baseline incidence, expected for especially in relation to new diagnostic procedures that can a given radiation exposure. In the present report, the result in high doses; perform a comprehensive assessment doubling dose has been estimated using spontaneous of radon in homes and workplaces; and examine the effects mutation rates of human genes and radiation-induced of radiation on the environment as part of a study on mutation rates of mouse genes, because there are no data on radioecology. The Committee also plans to use the cellular radiation-induced mutations in humans. The Committee and molecular concepts of its 2000 report to address radiation now estimates the doubling dose to be of the order of one effects at the level of tissues and organs; examine the potential gray for low-dose, sparsely ionizing radiation. This is consequences for development of cancer risk from radiation of essentially the same as in earlier reports of the Committee, newly identified cellular responses to radiation; continue to but supported by more data. perform epidemiological evaluation of cancer and additionally of diseases other than cancer that may be increased by 9. For a population exposed to radiation in one radiation; and continue its studies on the radiological health generation only, the risks to the progeny of the first post- effects from the Chernobyl accident. Those studies are radiation generation are estimated to be 3,000 to 4,700 expected to be completed and published in 2005. Notes 1 The United Nations Scientific Committee on the Effects of Atomic ment No. 45 (A/37/45); ibid., Forty-first Session, Supplement No. 16 Radiation was established by the General Assembly at its tenth (A/41/16); ibid., Forty-third Session, Supplement No. 45 (A/43/45), ibid., session, in 1955. Its terms of reference are set out in resolution Forty-eighth Session, Supplement No. 46 (A/48/46); ibid., Forty-ninth 913 (X) of 3 December 1955. The Committee was originally Session, Supplement No. 46 (A/49/46); ibid. Fifty-first Session, composed of the following Member States: Argentina, Australia, Supplement No. 46 (A/51/46); and ibid., Fifty-fifth Session, Supplement Belgium, Brazil, Canada, Czechoslovakia, Egypt, France, India, No. 46 (A/55/46 and Corr.1 Arabic only). These documents are referred Japan, Mexico, Sweden, Union of Soviet Socialist Republics, United to as the 1958, 1962, 1964, 1966, 1969, 1972, 1977, 1982, 1986, 1988, Kingdom of Great Britain and Northern Ireland and United States of 1993, 1994, 1996 and 2000 reports, respectively. The 1972 report, with America. The membership of the Committee was subsequently scientific annexes, was published as Ionizing Radiation: Levels and enlarged by the Assembly in its resolution 3154 C (XXVIII) of Effects, Volume I: Levels and Volume II: Effects (United Nations 14 December 1973 to include the Federal Republic of Germany, publication, Sales Nos. E.72.IX.17 and 18). The 1977 report, with Indonesia, Peru, Poland and the Sudan. By its resolution 41/62 B of scientific annexes, was published as Sources and Effects of Ionizing 3 December 1986, the Assembly increased the membership of the Radiation (United Nations publication, Sales No. E.77.IX.1). The 1982 Committee to a maximum of 21 members and invited China to report, with scientific annexes, was published as Ionizing Radiation: become a member. Sources and Biological Effects (United Nations publication, Sales No. E.82.IX.8). The 1986 report, with scientific annexes, was published as 2 For the previous substantive reports of the United Nations Scientific Genetic and Somatic Effects of Ionizing Radiation (United Nations Committee on the Effects of Atomic Radiation to the General publication, Sales No. E.86.IX.9). The 1988 report, with scientific Assembly, see Official Records of the General Assembly, Thirteenth annexes, was published as Sources, Effects and Risks of Ionizing Session, Supplement No.