HEAVY METALS CONCENTRATION AND METALLOTHIONEIN CONTENT IN RESIDENT AND CAGED MUSSELS Mytilus galloprovincialis FROM RIJEKA BAY, CROATIA

Concentration of lead, cadmium, mercury, arsenic, copper, zinc, chromium, nickel, manganese and iron and metallothionein content were examined in resident and caged mussels (Mytilus galloprovincialis) at five sites along Rijeka Bay, a coastal ecosystem highly susceptible to urban and industrial pollution. Higher concentration of metals was found in resident mussels, with the highest level in comparison to control site Lim detected for lead, copper and chromium. Caged mussels from all sites displayed increasing level of metals with respect to control site Lim after one month of exposure. Significantly elevated metallothionein content was found in resident mussels at all sites except Kraljevica shipyard, and in caged mussels at sites Luka Rijeka harbour and urban area Bakar. PCA analysis revealed that mussels resident to urban area of river Rjecina mouth, Rijeka harbour and Treci Maj shipyard were clearly separated from Kraljevica shipyard due to different pattern of metal bioaccumulation and metallothionein content. Resident mussels from urban area of Bakar and caged mussels were less influenced by metal load.