Modelling the dispersion of 137Cs and 239Pu released from dumped waste in the Kara Sea

Three-dimensional, baroclinic, circulation models are applied to study the dispersal of radioactivity in the Barents Sea and Kara Sea. The release is supposed to occur at underwater dump sites for radioactive waste in the Kara Sea, used by the former Soviet Union. Two different spatial scales of dispersion are considered: the regional scale (the far field), which covers the shelves of the Barents and Kara Seas and the local scale (the near field) which is focused mainly on Abrasimov Bay where the dumping partly took place. The regional-scale model results suggest that, even for a worst case scenario, the radioactive contamination of Siberian coastal waters would be relatively small compared to observations in other marine systems (e.g the Baltic Sea and the Irish Sea). Realistic gradual release scenarios show very low concentrations in the central and eastern Kara Sea. A significant contamination of surrounding seas like the Laptev Sea, the Arctic Ocean or the Barents Sea by radioactive waste dispersion from the Kara Sea seems to be unlikely.