Assessment of the impact of chemical pollutants on mussel, Mytilus galloprovincialis, from the Venice Lagoon, Italy

Abstract

The purpose of this study was to identify possible relationships between biochemical—Catalase, Superoxide dismutase (SOD) and Propionaldehyde dehydrogenase (PDH)—and histochemical—Neutral Red Retention time (NRR)—parameters of mussels ( Mytilus galloprovincialis) and chemical (Hg, Pb, Cd, Zn, Cr, DDTs and PCBs) contaminants from the most polluted area of the Venice Lagoon which lies around Porto Marghera (industrial pollution) and the city of Venice (domestic pollution). Sampling of mussels was undertaken at the beginning of March 1995 and repeated in March 1996, just before spawning, when tissue concentrations of chemical pollutants reach their annual maxima. The results of the organic contaminant analysis showed generally good agreement between sites for the two sampling periods, with values broadly 10% lower during 1996 as compared to 1995. Metal contaminant concentrations in tissues revealed greater variability than organic compounds. Distribution pattern of biological parameters were more complex and variable. The apparent lack of significant positive correlations between antioxidant enzyme activities and pollutant body burdens as well as the low values of NRR are consistent with the present debate on the use of these biological indices as markers of contaminant-mediated stress for molluscs.