Reconstruction of the Internal Dose in Population from Radioactive Releases

INTRODUCTION The need for retrospective assessments of the internal doses received by members of the public as a result of large environmental releases of radionuclides arose in connection with the atmospheric nuclear weapons tests conducted in the 1950s and 1960s as well as with major radiation accidents. The assessment of the internal exposure is greatly facilitated when measurements of the radionuclides in the body or in specific organs are available, or when use can be made of the results of systematic monitoring of the radionuclide content of foodstuffs. This was the case for the incorporation of Sr by inhabitants of the Techa river basin in the early 1950s (7, 10), for I and shorter-lived radioiodines by residents of the Marshall Islands in 1954 (6), for Sr-90 and other radionuclides by inhabitants of Urals after the Kyshtim accident in 1957, for I-131 and Cs-137 in UK after the fire of the Windscale reactor in 1957 (5), for Cs and Sr following radioactive fallout from atmospheric nuclear weapons tests in the 1950s and 1960s, for I, Cs and Cs after the Chernobyl accident in 1986 (2, 4, 8, 11, 16), and for Cs after the radiological accident in Goiania in 1987. These radionuclides were incorporated in the body mainly via ingestion of milk, other food products and drinking water. The contribution of inhalation in the internal dose was significant only in special circumstances: when inhabitants were evacuated from contaminated areas or when consumption of contaminated food was prevented. The main purposes of the internal dose reconstruction efforts were the assessment of the risks from radiation to human health and the application of laws related to the protection of the populations living in areas contaminated with radionuclides.