Caesium-137 distribution, inventories and accumulation history in the Baltic Sea sediments

• Published in: Journal of environmental radioactivity Vol. 127; pp. 11 - 25
• Main Authors: Zaborska, Agata, Winogradow, Aleksandra, Pempkowiak, Janusz
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.01.2014; Elsevier
• Subjects: anthropogenic activities; Applied sciences; Baltic Sea; Biological and physicochemical properties of pollutants. Interaction in the soil; bioturbation; cesium; Cesium Radioisotopes - analysis; Chernobyl Nuclear Accident; Contamination; Cs-137; Deposition; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Monitoring - methods; Exact sciences and technology; Finland; Fluxes; Geologic Sediments - analysis; Hazardous; Inventories; monitoring; nuclear power; Nuclear power plant; Oceans and Seas; Poland; Pollution; Pollution, environment geology; power plants; Radiation Monitoring - methods; Radionuclides; Sediments; Soil and sediments pollution; Stations; Stockpiling; toxic substances; Water Pollutants, Radioactive - analysis; watersheds; Baltic Sea; Poland; Finland; Ukraine, Chernobyl; ANE, Baltic Sea; ANE, Baltic Sea, Bothnia Gulf, Bothnian Bay; ANE, Poland; Radionuclides; Nuclear power plant; Cs-137; Baltic Sea; Contamination; Cesium 137; Radioactive pollution; Marine sediments; Pollutant behavior; Historical aspects; Radioisotope; Spatial variation; Radioactivity measurement; Nuclear accident; Depth profile; Fission reactor accidents; Pollution source; Anthropogenic factor
• ISSN: 0265-931X; 1879-1700; 1879-1700
• DOI: 10.1016/j.jenvrad.2013.09.003

The Baltic Sea is susceptible to pollution by hazardous substances due to limited water exchange, shallowness, and the large catchment area. Radionuclides, particularly 137Cs, are one of the most hazardous anthropogenic substances present in the Baltic environment. This study was conducted to present 137Cs present contamination that should further be a subject of reliable monitoring when the new Nuclear Power Plant is put into operation in the northern Poland. The sea-wide, up to date distribution of 137Cs activities and inventories in the Baltic Sea bottom sediments are presented. The 137Cs activity concentrations were measured in 30 cm long sediment cores collected at 22 sampling stations. Sediment accumulation rates were quantified by 210Pb geochronology to follow the history of 137Cs accumulation. The 137Cs inventories and fluxes were calculated. Most of the Baltic Sea sediments accumulated 137Cs in the range from 750 to 2675 Bq m−2. The Bothnian Bay is severely contaminated by 137Cs with inventories up to 95,191 Bq m−2. This region is moreover characterized by extremely large patchiness of 137Cs inventories. The 137Cs annual fluxes are highest at the two stations located at the Bothnian Bay (342 Bq m−2 and 527 Bq m−2) due to large Chernobyl 137Cs contamination of that region and high sediment accumulation rates. When these stations are excluded, the recent, annual mean value of 137Cs load to the Baltic Sea deposits is 38 ± 22 Bq m−2. The distribution of radio-caesium inventories over the Baltic Sea nowadays reflects the pattern of Chernobyl contamination. The radio-caesium deposited in surface sediments is not permanently buried, but may be resuspended and redeposited by currents, bioturbation or anthropogenic activities. •137Cs contamination in the Baltic Sea was studied before the new NPP is put into operation.•Bothnian Sea sediments are severely contaminated by 137Cs (inventories up to 95,191 Bq m−2).•Most of the Baltic Sea sediments accumulated 137Cs in the range from 750 to 2675 Bq m−2.•The 137Cs accumulation history in some areas is affected by environmental processes.•The recent, annual mean 137Cs load to the Baltic Sea deposits is 38 ± 22 Bq m−2.