The importance of radiation risk assessment

In its Publication 26, ICRP recommends a system of radiation dose limitation that is designed to ensure adequate protection from the harmful effects of radiation in conditions both of occupational and of environmental exposure. Clearly, however, no such system can be recommended or accepted as sufficiently safe unless the risks of the resultant exposures have been quantitatively assessed. Publication 26 reflects the increasing quantitative information that is now available on (a) carcinogenic risks of radiation in man, both from exposure of the whole body and from that of individual organs, at moderate exposures; (b) theoretical bases for inference of risk, from moderate to lower exposures; (c) genetic risks in the mouse, and inferences from such risks to those in man; (d) the dose equivalent levels at which certain non-stochastic effects may be induced. Despite a number of uncertainties, substantially improved estimates can therefore be made of the levels of safety that are likely to be achieved by observing the Commission's recommended dose limits, and the associated system of limitation of exposures to levels as low as reasonably achievable below these limits. Both for occupational exposure and for the exposure of the members of the public, these estimates are expressed in Publication 26 in terms of the risk of inducing fatal malignancies or serious hereditary ill health. These frequencies are compared with those of occupational fatalities in other industries or with accidental fatalities amongst the general public. The comparison between harm from radiation and from other agents in different industries is extended in ICRP-27 (on ''Problems Involved in Developing an Index of Harm'') in a review of the time lost through occupational diseases and non-fatal accidents, as well as from fatal diseases and accidents, so that the levels of safety achievable by the Commission's recommendations can be reviewed in the general perspective of occupational safety. (author)