Assessment of the current levels of ²⁴¹Am и ¹³⁷Сs in soils and foodstuff, as well as of public internal exposure to ionizing radiation in populated areas adjacent to the Chernobyl NPP exclusion zone (case study: the Bragin district of the Gomel region, Belarus)

This paper is part of a research cycle focusing on studying the current levels of  ²⁴¹Am and ¹³⁷Cs in soils and local foodstuffs of populated areas neighboring the Chernobyl exclusion zone. Our objective was to estimate the maximum annual committed internal doses to individuals of the Bragin-area settlements from inhalation and consumption of locally produced foods. We updated the data on the levels of  ²⁴¹Am and ¹³⁷Сs in soils of 28 settlements of the district. Specific activity of  ²⁴¹Am in soils in two of the settlements were the highest of all; we took and analyzed samples of local-grown foodstuff.  ²⁴¹Am in food samples was measured via a radiochemical method with the use of selective chromatographic resins and alpha-spectrometry measurement. A gammaspectrometry technique was used to measure  ²⁴¹Am in soil and ¹³⁷Сs in soil and food samples. The most contaminated by  ²⁴¹Am and ¹³⁷Cs appeared the soils in the town of Bragin, the administrative center of the district where the respective levels were as high as 2.8 and 560 kBq/m2. Among the analyzed samples, the specific activities of  ²⁴¹Am in root and tuber crops were one-digit values, while the samples of leafy vegetables contained a few tens of mBq/kg of the same radionuclide. That said, however,  ²⁴¹Am concentrations in food samples were lower than those of ¹³⁷Сs by three orders of magnitude. The results showed an apparent difference between estimated annual committed internal doses to the Bragin residents due to  ²⁴¹Am intake and that resulting from ¹³⁷Сs with the respective 0.03 and 1.7 mSv/year. The maximum doses to population of the Bragin-district villages from inhalation of  ²⁴¹Am varied from 0.006 to 0.033 mSv/year exceeding the doses from inhaled ¹³⁷Сs – 0.0002-0.002 mSv/year – by one order of magnitude. The major contribution to the public internal exposure today is ¹³⁷Сs intake through consumption of contaminated food that produced locally; its contribution is about 93-99% of the total internal dose received by the Bragin-district residents.

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