PNNL

Abstract

The East Urals Radioactive Trace (EURT) was formed after a chemical explosion in the radioactive waste-storage facility of the Mayak Production Association in 1957 (Southern Urals, Russia) resulted in the dispersion of 7.4×1016 Bq into the atmosphere. The internal exposure due to ingestion of radionuclides with local foodstuffs was the main factor of public exposure at the EURT. The EURT cohort, combining residents of most contaminated settlements, was formed for epidemiological study at URCRM. For the purpose of improvement of radionuclide intake estimates for cohort members, the following data sets collected in URCRM were used: (1) Total ß- activity and radiochemical measurements of 90Sr in local foodstuffs over all of the period of interest (1958-2011; n=2200), the data were used for relative 90Sr intake estimations. (2) 90Sr measurements in human bones and whole body (n=338), the data were used for average 90Sr intake derivations using an age- and genderdependent Sr-biokinetic model. Non-strontium radionuclide intakes were evaluated on the basis of 90Sr intake data and the radionuclide composition of contaminated foodstuffs. Validation of radionuclide intakes during the first years after the accident was first carried out using measurements of the feces ß-activity of EURT residents (n=148). The comparison of experimental and reconstructed values of feces ß-activity shows good agreement. 90Sr intakes for residents of settlements evacuated 7-14 days after the accident were also obtained from 90Sr measurements in human bone and whole body. The results of radionuclide intake reconstruction will be used to estimate the internal doses for the members of the EURT cohort.