Calculations of individual doses for Techa River Cohort members exposed to atmospheric radioiodine from Mayak releases

Publication date: November 2017
Source:Journal of Environmental Radioactivity, Volumes 178–179
Author(s): Bruce A. Napier, Paul W. Eslinger, Evgenia I. Tolstykh, Marina I. Vorobiova, Elena E. Tokareva, Boris N. Akhramenko, Victor A. Krivoschapov, Marina O. Degteva
Time-dependent thyroid doses were reconstructed for over 29,000 Techa River Cohort members living near the Mayak production facilities from ¹³¹I released to the atmosphere for all relevant exposure pathways. The calculational approach uses four general steps: 1) construct estimates of releases of ¹³¹I to the air from production facilities; 2) model the transport of ¹³¹I in the air and subsequent deposition on the ground and vegetation; 3) model the accumulation of ¹³¹I in environmental media; and 4) calculate individualized doses. The dose calculations are implemented in a Monte Carlo framework that produces best estimates and confidence intervals of dose time-histories. Other radionuclide contributors to thyroid dose were evaluated. The ¹³¹I contribution was 75–99% of the thyroid dose. The mean total thyroid dose for cohort members was 193 mGy and the median was 53 mGy. Thyroid doses for about 3% of cohort members were larger than 1 Gy. About 7% of children born in 1940–1950 had doses larger than 1 Gy. The uncertainty in the ¹³¹I dose estimates is low enough for this approach to be used in regional epidemiological studies.



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