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 regions. Nevertheless polar ecosystems may contain relatively high levels of radioactive contamination. This is true, in particular, for the Arctic regions, which beside global fallout have received significant amounts of radioactivity from a number of other sources. Some of the sources viz discharges from nuclear reprocessing in Western Europe and the Chernobyl accident are well described. Others, such as local fallout from 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 contribute significantly to the observed and future contamination of the Arctic. Although the radioecological sensitivity of food products front Arctic regions tend to be higher than we know it from temperate regions, the very low productivity Of Nordic regions imply low collective doses front these regions. However, high individual doses from radioactive contamination may be seen in the Arctic as it has been observed for, e.g. reindeers breeders. Radiocaesium is concentrated from lower to higher trophic levels. The marine animals contain orders of magnitude lower 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 characterized with extremely low levels of anthropogenic radioactive contamination. However data are sparse compared to the Arctic.