Transfer of natural radionuclides in terrestrial food chains – A review of investigations in Finland

Transfer of natural radionuclides 210Pb, 210Po, 238U, and 228,230,232Th in subarctic food chains has been studied in Finland since the 1960’s. The unique food chain lichen-reindeer-man related to Sami people in Finnish Lapland and other food chain options starting from berries or mush-room ending to man have been explored and the activity concentrations of natural radionuclides in biological samples determined. The results from Finnish radioecological studies are being summarized and differences in bioaccumulation between different radionuclides are discussed. It was found out that although a substantial amount of activity concentration data exist from the research projects executed in Finland during the last six decades, more data especially from U and Th in biological environment and humans would be useful, e.g., for modeling purposes and for improved assessment of bioaccumulation and adverse effects (both radiological and chemi-cal) of radionuclides.