RADIOMETRIC INVESTIGATIONS OF KARA SEA SEDIMENTS AND PRELIMINARY RADIOLOGICAL ASSESSMENT RELATED TO DUMPING OF RADIOACTIVE-WASTES IN THE ARCTIC SEAS

There has been world-wide concern over the possible health and environ mental impacts of the dumping of radioactive wastes in shallow waters of the Kara and Barents Seas. During 1992, IAEA-MEL participated in a joint Russian-Norwegian expedition to the region and collected a suite of sediment cores for characterization of downcore radioactivity dist ribution patterns and inventories with the aim of assessing past and p resent inputs of radionuclides. The Cs-137, Pu-238, Pu-239,Pu-240, and Am-241 contents of the 0-1 cm sections range from 17 to 32, 0.01 to 0 .06, 0.4 to 1.3 and 0.2 to 0.5 Bq kg(-1) (dry wt), respectively. The P u-238/Pu-239,Pu-240 and Am-241/Pu-239,Pu-240 activity ratios are consi stent with those reported for global fallout. Detailed information on downcore radionuclide distribution patterns and inventories, as well a s an account of sedimentation parameters, are presented. A preliminary assessment of the long-term radiological impact of radioactive waste disposal in the Arctic Seas, on global and regional scales, has been m ade. The modelling results suggest that the global radiological impact of the disposals will be comparable to or less than those resulting f rom other anthropogenic and natural sources of radioactivity. However, radiological effects on the regional scale may be of importance. IAEA is carry out a 4 year international arctic seas assessment Project (I ASAP) that will comprehensively cover all aspects of radioactive dumpi ng in the Arctic seas and it will be reported to the London convention in 1996. The IAEA-MEL study described here represents a preliminary c ontribution to IASAP.