RADIOACTIVITY IN POLAR-REGIONS - MAIN SOURCES

The common source of anthropogenic radioactivity of the polar regions has been global fallout from nuclear weapons testing in the atmosphere . The depositions from this source are at a minimum in the polar regio ns. Nevertheless polar ecosystems may contain relatively high levels o f radioactive contamination. This is true, in particular, for the Arct ic regions, which beside global fallout have received significant amou nts of radioactivity from a number of other sources. Some of the sourc es viz discharges from nuclear reprocessing in Western Europe and the Chernobyl accident are well described. Others, such as local fallout f rom the Novaya Zemlya test cite, discharges from nuclear facilities to the Siberian rivers Ob, Yenisey and Lena and dumping of nuclear waste in the Barents and Kara Seas are less well documented, but may contri bute significantly to the observed and future contamination of the Arc tic. Although the radioecological sensitivity of food products front A rctic regions tend to be higher than we know it from temperate regions , the very low productivity Of Nordic regions imply low collective dos es front these regions. However, high individual doses from radioactiv e contamination may be seen in the Arctic as it has been observed for, e.g. reindeers breeders. Radiocaesium is concentrated from lower to h igher trophic levels. The marine animals contain orders of magnitude l ower Cs-137 levels than terrestrial animals in Arctic regions and the transfer of Cs-137 is one to two orders of magnitude greater than that of Sr-90 to meat of animals. The Antarctic continent is apparently ch aracterized with extremely low levels of anthropogenic radioactive con tamination. However data are sparse compared to the Arctic.