Bioaccumulation and biomarker responses of trace metals and micro-organic pollutants in mussels and fish from the Lagoon of Venice, Italy

The aims of this study were to evaluate levels and effects of trace metals (Cd, Cr, Cu, Fe, Mn, Pb, Zn), PAHs and PCBs in mussels and fish native to the Lagoon of Venice. To this end, bioaccumulation and various biomarkers of generic stress and exposure (malondialdehyde, MDA and metallothioneins, MT; ethoxyresorufin O-deethylase activity, EROD; fluorescent bile metabolites and somatic indices in fish; lysosomal membrane stability, LMS; lipofuscins, LF; neutral lipids, NL and survival-in-air, SOS in mussels) were measured in organisms seasonally collected from two differently influenced areas. In mussels, metal bioaccumulation levels at the two sites were low and fluctuated similarly, exhibiting decreasing levels in summer, like MDA and MT. Micro-organic pollutants and the probably related biological response of LMS did not show either significant site differences or seasonal trends. LF and NL revealed inconclusive patterns. The results of the survival-in-air test were quite erratic, showing that they were associated with the high variability of both natural and physiological parameters temperature, food, reproduction, and body reserve cycle. In fish, both inorganic and organic micropollutant levels were low, and differences were detected between sites only for PCBs. The pattern exhibited by micro-organic contaminants was clearly related to the reproductive cycle at both sites; a relationship with PCBs, EROD and MDA was established at the site where their levels were generally higher. Bile metabolites (3-OH benzo(a)pyrene, 1-OH pyrene) were associated with PAH contents.