Levels of radioactive substances in the Barents Sea remain the same29/04/2008
In August 2007 Ari-Pekka Leppänen, STUK’s senior scientist, got on board the Russian Dalnie Zelentsy. The research destination of the ship was the Barents Sea. The expedition was carried out by the mutual cooperation agreement of STUK and MMBI signed for two years ago. The trip took 20 days and about 3000 kilometres, during which approximately 60 samples were collected from the bottom sediment, sea water, fishes and other organisms. Particularly man-made radioactive substances, cesium, strontium and plutonium, were of special interest. The preliminary results of the analyses are now ready. They were presented in a joint seminar by STUK, MMBI and the Finnish Meteorological Institute (FMI) in Northern Finland, in Rovaniemi on April 29, 2008. ”Nothing alarming was detected in the analyses of the samples”, explains Dina Solatie, Head of the Regional Laboratory in Northern Finland. According to Solatie, nothing special was expected, either. However, the Russians have explored the Barents region already for decades and also the Finnish research data concerning the Barents Sea dates back several years. The concentrations of the man-made radioactive substances, cesium-137, plutonium-238 and plutonium-239, are small compared to the Baltic Sea that received a significant amount of the Chernobyl fallout. A little over one Becquerel of plutonium-239 per kilogram was detected in the samples. The plutonium seems to originate in nuclear weapons tests of the 1950s and 1960s. The man-made radionuclides and their activity ratios in the samples reveal the origin of the nuclides. For example, if the activity level of plutonium proves to be higher than before in the measurements, it may indicate that the nuclear waste submerged in the sea have started spreading. However, the present measurement results give no such indications. In one sediment sample from Kola section, traces of antimoni-125 (Sb-125) were detected. This nuclide, together with teknetium-99, is often associated with liquid releases. Dina Solatie presumes that antimoni nuclides might come from a nuclear waste reprocessing plant. Concerning natural radioactive substances, polonium-210, radium-226, uranium-235 and kalium-40 in the sediment samples were analysed. The activity concentrations of these substances were of the same level as those in the Baltic Sea sediment samples. Five of the samples were analysed at STUK, and the rest was measured by MMBI. The reliability of the analyses was verified by performing some measurements at both institutes and comparing the results. The results corresponded well to each other. The final measurement results will be published in scientific articles in early 2009. Additional information: Requests for contact and information: Head of Laboratory Dina Solatie, Radiation and Nuclear Safety Authority, Regional Laboratory of Northern Finland Page updated 07/01/2009
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