HEAVY METAL BIOACCUMULATION IN MYTILUS GALLOPROVINCIALIS: A TRANSPLANTATION EXPERIMENT IN VENICE LAGOON

Mussels were transplanted from a marine reference site to a polluted area of the Venice Lagoon to study heavy metal bioaccumulation responses in soft tissues and shells. Soft tissue levels of Mn, Cu, Fe and Cr were initially lower in reference than in lagoon resident mussels, while no differences were observed for Pb and Zn. After one month, the Mn, Cu, Fe and Cr levels in the transplanted mussels increased and overtook both values recorded in resident and marine organisms. Two months after transplantation, metal levels dropped off. At the time of the last sampling, the metal levels seemed to stabilize at lagoon values, except for Cu. Shell levels of Cu, Zn and Pb were lower in mussels from the reference site than in those resident in the lagoon. After three month from transplantation, the bioaccumulation shell data indicated a sharp increase in Mn, Fe and Zn overtaking the levels of lagoon resident bivalves. The results show the usefulness of field transplantation experiments in studying bioaccumulation responses in polluted coastal environments.