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Baltic Sea: Radionuclides

  1. Sven P. Nielsen1,
  2. Maria Lüning2,
  3. Erkki Ilus3,
  4. Iisa Outola3,
  5. Tarja Ikäheimonen3,
  6. Jukka Mattila4,
  7. Jürgen Herrmann5,
  8. Günter Kanisch6,
  9. Iolanda Osvath7

Published Online: 15 DEC 2011

DOI: 10.1002/9781119951438.eibc0447

Encyclopedia of Inorganic and Bioinorganic Chemistry

Encyclopedia of Inorganic and Bioinorganic Chemistry

How to Cite

Nielsen, S. P., Lüning, M., Ilus, E., Outola, I., Ikäheimonen, T., Mattila, J., Herrmann, J., Kanisch, G. and Osvath, I. 2011. Baltic Sea: Radionuclides. Encyclopedia of Inorganic and Bioinorganic Chemistry. .

Author Information

  1. 1

    Technical University of Denmark, Roskilde, Denmark

  2. 2

    Swedish Radiation Safety Authority, Solna, Sweden

  3. 3

    Radiation and Nuclear Safety Authority, Helsingfors, Finland

  4. 4

    Water and Environment of the River Kymi, Kouvola, Finland

  5. 5

    Federal Maritime and Hydrographic Agency, Hamburg, Germany

  6. 6

    Johann Heinrich von Thünen-Institute, Hamburg, Germany

  7. 7

    International Atomic Energy Agency, Monaco

Publication History

  1. Published Online: 15 DEC 2011


The most significant source of anthropogenic radioactivity in the Baltic Sea is fallout from the accident at the Chernobyl nuclear power plant in 1986. The second most important source is global fallout from atmospheric nuclear weapons tests carried out during the late 1950s and early 1960s. Radioactivity inputs into the Baltic Sea from nuclear reprocessing plants in Western Europe have become of minor importance due to significant reduction of discharges in recent years. In terms of input of 137Cs into the Baltic Sea, Chernobyl fallout has contributed about 82% and nuclear weapons test fallout about 14%. For 90Sr in the Baltic Sea, input from atmospheric fallout from nuclear weapons tests has contributed about 81%, while the contribution from Chernobyl fallout was about 13%. Cesium-137 is the main indicator of Baltic seawater with respect to anthropogenic radioactivity. The highest concentrations in seawater during 1999–2006 were found in the Baltic Proper and the Bothnian Sea. The general trend is steadily decreasing. Concentrations of anthropogenic radioactivity in fish generally show decreasing trends in agreement with concentrations in seawater. Among freshwater fish, pike showed large 137Cs values due to their higher concentration factors (CFs). The larger 137Cs values of pike were observed at the coast of the Bothnian Sea. The Baltic Sea is the regional sea in the world with the highest concentrations of 137Cs. The Baltic Sea ranks third in the world with respect to 90Sr in seawater; only the Irish Sea and the Black Sea show higher levels. In 1990, average concentrations of 137Cs in fish from the Baltic Sea were similar to those in the Irish Sea, about 4 times higher than in the Black Sea and about 30 times higher than in the Mediterranean Sea.


  • Baltic Sea;
  • anthropogenic radionuclides;
  • natural radionuclides;
  • seawater;
  • sediment;
  • biota;
  • inventories