241Am on the territories adjacent to the Belarusian sector of the Chernobyl NPP resettlement zone: soil contamination, foodstuffs and population internal dose assessment

Abstract

241Am is the only radionuclide of Chernobyl radioactive fallout the content of which until 2058 continues to increase. The purpose of this work is to assess the 241Am internal exposure doses of residents of settlements on the territory adjacent to the resettlement lands of the Chernobyl nuclear power plant. To achieve this goal the current levels of 241Am and accompanying 137Cs content in the soil and foodstuffs were determined at the private settlements of the Bragin district of Gomel region of Belarus. 241Am (Eγ 59.6 keV) content in soil samples and 137Сs (Eγ 661 keV) content in soil/food samples were determined by gamma spectrometry. Determination of 241Am specific activity in food samples was performed by the radiochemical method using selective extraction-chromatographic resins. With an average level of 1.3 kBq/m2 , the maximum soil contamination density of 241Am can reach 3.6 kBq/m2 , and for 137Cs it is one or two orders of magnitude higher and ranges from 50 kBq/m2 to 350 kBq/m2 . The maximum specific activity of 241Am in products is determined in samples of leafy parsley – 33 mBq/kg, and in samples of potatoes, beets, onions per feather – not exceed 5 mBq/kg. The content of accompanying 137Cs in samples of plant products is in the range of 3-12 Bq/kg. In estimation of the internal dose of exposure by the food chain it is conservatively assumed that the population receives all the main components of the diet in their own farmstead. Calculation of the dose of internal exposure during inhalation is made under the assumption that the population performs work in the garden 4 hours a day for 7 months. The total expected dose of internal exposure from 241Am residents of settlements is dominated by the inhalation component, while the oral route is dominant in the formation of the total dose of internal exposure from concomitant 137Сs, which is 20 or more times higher than 241Am.