In situ monitoring of mussel populations in the Venice Lagoon by means of molecular biomarkers

Abstract The environmental stress of Mytilus sp. specimens collected from five specific sites in the Venice Lagoon (and from one offshore site nearby) has been investigated by means of different ecotoxicological biomarkers. The study evaluated genotoxic and cytotoxic effects, such as DNA strand breaks and apoptosis, on the digestive gland cells of mussels by using the Single Cell Gel Electrophoresis Test, i.e. Comet Assay. In order to assess the temporal and spatial trends of these biomarkers within the Venice Lagoon, the same sampling scheme was repeated in two field studies: mussels were collected monthly for a period of seven months from December 1999 to June 2000 and then from December 2005 to June 2006. Regarding the temporal trend, the DNA damage values were lower in the 2006 study than in the 2000 study. However cell mortality values in the second monitoring were almost double those of the first one. As for the spatial trend, in both studies mussels collected from the Venice Lagoon showed a higher level of DNA damage than offshore mussels, a trend that increased significantly as we moved from the lagoon border towards the lagoon interior.