Contamination of the southern Baltic Sea with 137Cs and 90Sr over the period 2000-2004

Changes of the (137)Cs activity concentrations in the southern Baltic Sea waters were investigated over the period 2000-2004 and distribution of the (90)Sr concentrations was determined in 2004. In the discriminated period further decrease of (137)Cs concentrations was observed. The average activity concentration of (137)Cs declined from 59.4Bq/m(3) in 2000 to 45.1Bq/m(3) in 2004. The greatest changes of (137)Cs activities occurred in 2003 as a consequence of the medium-size inflow of a saline waters from the North Sea. This inflow affected (137)Cs activities as well as its distribution in the Baltic Sea. Changes in (90)Sr activity concentrations proceeded at much slower rate. The average activity concentration of (90)Sr was equal to 8.7Bq/m(3) in 2004. The annual fluvial (137)Cs fluxes from the Vistula river were also estimated. In 2000, the (137)Cs load from Vistula was of an order of 0.15TBq/year, and in 2004 0.05TBq/year.