Atmospheric deposition and riverine load of 90Sr and 137Cs to the Gulf of Gdansk (southern Baltic Sea) in the period 2005-2011

In the period 2005-2011 total atmospheric fallout and the riverine input to the Gulf of Gdansk was 1168.8 GBq of Sr-90 and 424.1 GBq Cs-137. The major source of both radionuclides to the Gulf of Gdansk is the Vistula river; its contribution reached 99.7% in the case of Sr-90 and 95.8% regarding Cs-137. The atmospheric load of Cs-137, 18.1 GBq, was nearly 4 times bigger than in the case of Sr-90 (3.75 GBq). In the period 2005-2010, the average annual atmospheric load were at the levels 2-3 GBq for Cs-137 and 0.4-0.6 GBq for Sr-90, while in 2011, due to the Fukuchima Dai-ichi power plant break down, an increase of annual atmospheric loads was noted to 5.3 GBq of Cs-137 and to 0.87 GBq of Sr-90. The additional loads did not have an increasing effect on the activity concentrations of Cs-137 and Sr-90 in seawater of the Gulf of Gdansk, where mean activity concentrations in seawater were equal to 31.1 Bq m(-3) and 7.6 Bq m(-3) in the case of (CS)-C-137 and Sr-90 respectively. (C) 2015 Elsevier Ltd. All rights reserved.