| NUKLEONIKA 2002, 47(2):45-52
VERTICAL DISTRIBUTION OF 137Cs, 210Pb, 226Ra AND 238,240Pu
IN BOTTOM SEDIMENTS FROM THE SOUTHERN BALTIC SEA
IN THE YEARS 1998-2000
Maria M. Suplińska
Department of Radiation Hygiene, Central Laboratory for Radiological Protection,
7 Konwaliowa Str., 03-194 Warsaw, Poland
This paper presents vertical distribution of 137Cs, 226Ra and 238,240Pu in bottom sediments collected from the Southern Baltic Sea in the years 1998-2000. In the southern part of Baltic Sea the highest concentrations of 137Cs and 239,240Pu were observed at the Gulf of Gdansk. Deposition of 137Cs ranged from 1990±402 Bq m-2 in the Bornholm Basin to 3260±820 Bq m-2 in the Gulf of Gdansk. Depositions of 239,240Pu in the Bornholm Basin were 28.1-30.4 Bq m-2 and in Gulf of Gdansk 161-174 Bq m-2. The concentration peaks of long lived radionuclides, owing to the sedimentation processes, show the maximum fallout period in different sediment layers. The observed differences in distribution of radiocaesium and plutonium along the profile confirm two main sources of contamination – Chernobyl fallout for 137Cs and global fallout in case of 239,240Pu. In chosen core samples from the Gdansk Basin vertical distribution of 210Pb concentrations were determined. Evaluated sedimentation rates based on decrease of unsupported 210Pb ranged in the Gdansk Basin from 1.9 to 2.3 mm year-1. Calculations based on 239,240Pu peaks show sedimentation rate, in the range from 1.6-2.2 mm year-1 for P110 region.
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