The inflow of (238)Pu and (239+240)Pu from the Vistula River catchment area to the Baltic Sea.

The aim of the work was to estimate plutonium inflow from the Vistula River's catchments area to the Baltic Sea. There were differences in plutonium activities depending on season and sampling site. The highest activities of (238)Pu and (239+240)Pu were transported from the Vistula River watershed to the Baltic Sea in spring and the lowest in summer. Annually, the southern Baltic Sea is enriched via the Vistula River with 10.3 MBq of (238)Pu and 89.0MBq of (239+240)Pu. The enhanced concentration of plutonium in water from the Vistula River is the result of its runoff from the Vistula drainage area, mostly from snowmelt, enhanced rainfalls and leached materials from river bed.