Health effects models for risk assessment of the Japanese population

Models have been developed to assess the health risks of Japanese population due to radiation exposure arising from a nuclear reactor accident, based principally on the health risk models by NUREG/CR-4214 and on the information derived from epidemiological studies on atomic bomb survivors of Hiroshima and Nagasaki. Health risks covered are (1) acute effects on bone marrow, lung, gastrointestinal tract, central nervous system, thyroid, skin and reproductive organs, (2) late somatic effects including leukemia and cancers of breast, lung, thyroid, gastrointestinal tract, and (3) late and developmental effects due to in utero exposure. As to the acute effects, Weibull function models were modified by incorporating a threshold concept. The resultant risk estimates are much more reasonable from the practical view point and more acceptable to the public in general who tends to demand zero risk. Models for leukemia, cancers of lung, gastrointestinal tract and thyroid, among others, were so developed as to incorporate newly acquired data on atomic bomb survivors with respect to dose-response, latency, risk projection and other relevant physiological parameters appropriate to the Japanese population