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0 The A bomb survivors in Japan'have been studied extensively and radiation hormesis has been claimed. For instance, survivors exposed to 500-1490 mSv showed significantly lower mortality from.non- cancerous diseases than unmatched controls (Mine et al., 1990), and similar patterns have been established for various cancers especially leukemia but at somewhat lower exposures (Kondo, 1990). However, the A-bomb caused short intense exposures so the survivors cannot be validly used as a test for radiation hormesis. in natural populations. The dilemma is that as the exposure to the A-bomb survivors approaches background, the sample size needed exceeds that available. This is highlighted by Vogel (1992) who comments "the bulk of the evidence points to only small effects of low or moderate radiation doses, effects that will probably be buried in the background noise of changing patterns of human morbidity and mortality". In view of the difficulties of accurately measuring the biological effects of low levels of exposure to ionizing radiation in humans, there is a need for experiments to seek evidence for hormesis in multicellular organisms that can be handled experimentally under controlled conditions. This is because the evolutionary expectation of hormesis is similar irrespective of taxa. In other words if a case for radiation hormesis were established in various invertebrate and vertebrate taxa at similar whole-of-life exposures, they should be applicable to humans as a first approximation. Such results could therefore assist in considerations of exposures in the context of radiation protection. REFERENCES Hickey, R.J., Bowers, E J., Spence, D.E., Zemel, B.S., Clelland, A.B. and Clelland, R.C. (1981). Low level ionizing radiation and human mortality: multiregional epidemiological studies. Health Phys. 40, 625-641. Kondo, S. (1990). Rational risk estimation in relation to atomic bomb radiation. J. Radiat. Res. 31,174188. Luckey, T.D. (1982). Physiological benefits from low levels of ionizing radiation. Health Phys. 43, 771-789. Mine, M., Okumura, V., Ichimaru, M., Nakamura, T. and Kondo, S. (1990). Apparently beneficial effects of low to intermediate doses of A-bomb radiation on human lifespan. Int. J. Radiat. Brol. 58, 1035-1043. Parsons, P.A. (1989). Acetaldehyde utilization in Drosophila: an example of hormesis. Biol. f. Linn. Soc. 37, 183-189. Parsons, P.A. (1990). Radiation hormesis: an evolutionary expectation and the evidence. App1. Radiat. Isot. 41, 857-860. Parsons,P:A. (1992). Evolutionary adaptation and stress:, the fitness gradient Eao1. BiaL,26, 191-223. . Planel, H., Suleflhavoup, J.P., Tixador, R., Richoilley, G., Conter, A., Croute, F:, Caratero, C. and Gaubin, Y. (1987). Influence :on cell proliferation of background exposure to very low, chro nic gamma radiation. Health Phys. 52, 571-578. Sagan, LA ac.d Cohen,JJ. (1990). Biological effects of low<lose radia.tion: overview and perspective. Health Phys. 59, 11-13. Vogel, F. (1992). Risk calculations for hereditary effects of ionizing radia tion in liumans: Human Genetics 89, 127-146. Wolff, S. (1939). Are radiation-induced effects hormetic? ' Sciena 245, 375. . , How t:o order BELLE BOoks "Biological Effects of Low Level Exposures to Chemicals and Radiation, 1992", ISBN 0-87371-665-5 and "Biological Effects of Low Level Exposures, Dose- Response Relationships, 1994", ISBN 1-56670-093-0. These books can be ordered by calling Lewis Publishers at 1-800-272-7737. Woulcl. Your Organization Like a BELLE Mini- Symposium/Workshop? ~ In 1994 BELLE has conducted four mini- symposia/workshops to date with a fifth scheduled for the Society of Risk Analysis, December 6th in Baltimore, 1lfaryland. Completed mini-symposia were conducted at the Society of Toxicology (Dallas), ACOEM {Chicago), MEDICHEM Congress (Melbourne, Australia), and American College of Toxicology ( Williamsburg) . As a result of the positive response to these respective BELLE mini-, symposia/workshops, we would like to continue to conduct tar,3eted BELLE mini-symposia/workshops with respect to various professional societies as well as public and private-sector organizations. If your organization is intersted in having a BELLE mini- symposium /workshop please contact the BELLE office at 413-545-3164. 89273285 Vol. 3, No. 2, Noaember 1994 11

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