Estimation of plutonium Pu budget in the Gulf of Gdańsk and the Gdańsk Basin (the southern Baltic Sea).

Presented have been the results of inventory estimation of anthropogenic beta-emitting Pu, in different components in the southern Baltic Sea ecosystem. The total Pu activity present in the Gulf of Gdańsk and the Gdańsk Basin for 2021 was estimated at 1.99 TBq and 7.82 TBq, respectively, of which 1.59 TBq and 6.38 TBq in the sediments. The Vistula and the Neman River and the atmospheric fallout were distinguished as the primary sources of plutonium in these basins. In seawater of the Gulf of Gdańsk, there was about 0.40 TBq Pu (20.1% of total activity) and 1.44 TBq Pu (18.4% of total activity) in the Gdańsk Basin. The Pu accumulated in living organisms in 2021 was 1.13 GBq in the Gulf of Gdańsk and 3.96 GBq in the Gdańsk Basin. In the Gulf of Gdańsk biota, 55.7% was accumulated in zoobenthos, while in the Gdańsk Basin, 48.3% was in zoobenthos.