Budget of 90Sr in the Gulf of Gdansk (southern Baltic Sea)

In the period from 2005 to 2011 the major source of Sr-90 to the Gulf of Gdansk was the Vistula river. Its contribution was 99.7% of the total load. The main processes responsible for the decrease in Sr-90 activity in the Gulf of Gdansk were: radioactive decay (87%) and sediment deposition (13%). Average increase in the activity of Sr-90 in the Gulf of Gdansk during the study period was 5.0% (114 GBq), which was almost 2 times higher than the loss of Sr-90 due to radioactive decay. In the years 1997-2015, the effective half-life of Cs-137 was 9.1 years and that of Sr-90 was 50.3 years. Assuming a further decrease in Cs-137 and maintaining Sr-90 concentrations at present level, it is expected that Sr-90 will become the major anthropogenic isotope having impact on the level of radioactivity in the Gulf of Gdansk. (C) 2017 Institute of Oceanology of the Polish Academy of Sciences. Production and hosting by Elsevier Sp. z o.o.