Speciation of heavy metals in marine sediments vs their bioaccumulation bymussels

Total contents and speciation of selected heavy metals, including Al, Fe, C o, Ni, Pb, Zn, Cu, Cr, were measured in sediment samples and mussels Mya ar enaria and Astarte borealis collected in the Horsund Fjord off Spitsbergen (Norwegian Sea) and the Bay of Gdansk (Baltic Sea). The investigation aimed at revealing differences in the accumulation pattern of heavy metals in mu ssels inhabiting sediments characterized by varying metal bioavailability. The contents of metals adsorbed to sediments and associated with iron and m anganese hydroxides, which were obtained by sequential extraction, were uti lized as a measure of metal bioavailability. The contents of Cd, Pb, Zn, Cu and Cr in mussels collected off Spitsbergen were generally lower than thos e in mussels from the Baltic Sea. In sediments collected off Spitsbergen th e bioavailable fraction represented a small proportion (0-3.7% adsorbed met als and 0-11% associated with metals hydroxides) of total heavy metal conte nts. In sediments from the Baltic Sea the percentages of metals adsorbed an d bound to hydroxides were 1-46% and 1-13%, respectively. The differences i n bioavailable metal contents measured in sediments were utilized to explai n the different contents of metals in mussels collected in the correspondin g sites.