Radioactivity In The Baltic Sea: Inventories And Temporal Trends Of Cs-137 And Sr-90 In Water And Sediments

The Baltic Sea is ecologically unique as one of the world's largest brackish water basins. It was significantly contaminated by radioactivity following the Chernobyl accident in 1986, the major contaminant being long-lived Cs-137. Due to the slow exchange of water between the Baltic Sea and the North Sea and the relatively rapid sedimentation rates, radionuclides have prolonged residence times in the Baltic Sea. Cs-137 levels are consequently still clearly higher than in other water bodies around the world. In addition to the Chernobyl accident, artificial radionuclides in the Baltic Sea originate from the global fallout following nuclear weapons testing in the 1950s and 1960s, while discharges into the Baltic Sea from nuclear power plants and other facilities are of minor importance. Here, inventories and the temporal evolution of radionuclides both in seawater and sediments of the Baltic Sea are presented and discussed.