THE ROLE OF THE BLUE MUSSEL, MYTILUS-EDULIS, IN THE CYCLING OF HYDROPHOBIC ORGANIC CONTAMINANTS IN THE BALTIC PROPER

Annual budgets were established for the flows of three important group s of hydrophobic organic contaminants (HOCs), i.e. polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polychlori nated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), through the dense blue mussel population inhabiting the Swedish coastal zone of the Bal tic proper. The budgets clearly show that the blue mussel significantl y modifies the flow of all three of the examined groups of HOCs by: i) increasing the net deposition of HOCs to the bottoms by 13-19% and, t hus, enhancing the availability of these contaminants to other benthic organisms; ii) increasing the retention time of HOCs in the water mas s by recycling substantial amounts of HOCs back to the pelagic system through passive elimination; iii) bioaccumulating large amounts of HOC s and, thus, constituting a significant source of contaminants for the demersal fish and waterfowl species that feed on mussels; iv) liberat ing considerable amounts of HOCs to coastal waters of the Baltic prope r via their spawning products, which may contribute significantly to t he HOC exposure of herring larvae and other zooplanktivores.