A comparison of 210Po accumulation in molluscs from the southern Baltic, the coast of Spitsbergen and Sasek Wielki Lake in Poland

210Po was analysed in the tissues and organs of four different species of molluscs originating from the Gulf of Gda sk and S upsk Narrow (Mytilus trossulus, Mya arenaria), Southern coast of Spitsbergen (Chlamys islandicus), and Sasek Wielki Lake in north-east Poland (Anodonta cygnea). The results show a great disproportion in the 210Po distribution within the molluscs examined. The highest 210Po concentrations were found in the hepatopancreas of the Baltic and freshwater species whereas for the polar molluscs the highest values were observed in gills. The 210Po/210Pb activity ratio was calculated exclusively for the Baltic bivalves. The value of the ratio greatly exceeds unity for all organs and tissues (except for the shell of Mya arenaria). The concentration factor CF for the total soft tissue of all the molluscs analysed varies in the range of 3600–72,000.