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

Effects and fate of sediment-sorbed linear alkylbenzene sulphonate (LAS) on the bivalve mollusk Mytilus galloprovincialis Lmk.

The toxicity of LAS on aquatic animals has been evaluated in particular relation to its concentration in water, although it is well known that sediments play an important role as repositories and sources of many contaminants, including surfactants. The aim of this study was to evaluate the effects of sediment-sorbed LAS on the marine mussel Mytilus galloprovincialis exposed to sediments drugged with 132 mg/kg dry weight of LAS mixtures. Four experiments were performed and some physiological parameters (filtration, oxygen uptake, nitrogen excretion) were measured on control and treated animals. In order to study uptake and release of sediment-sorbed LAS by mussels, quantification of weight, percentage of organic matter, LAS concentration and LAS homologue distribution on faeces were determined. Results showed no significant differences in physiological responses of treated mussels compared to controls, and the absence of a toxic action of LAS contaminated sediments. Moreover one notable aspect was that higher LAS concentrations were found in faeces than in uningested sediments recovered from water. This fact is tentatively explained either as the result of decreased desorption in the mussel intestinal tract with respect to circulating water, or as enrichment in fine particles by mussel filter feeding activity

MONITORING ENVIRONMENTAL STRESS IN INDIGENOUS BLUE MUSSELS ( MYTILUS SP) SAMPLED FROM THE LAGOON OF VENICE

The environmental stress of Mytilus sp. specimens collected from the mussel populations of four specific sites inside the Lagoon of Venice and from one offshore site nearby, has been investigated by means of an ecotoxicological biomarker. The approach has been applied to the Lagoon of Venice in that it constitutes the drainage basin of a highly industrialized region. The study concerned the genotoxic effects, evaluated as DNA strand breaks by single cell gel electrophoresis, in digestive gland cells and in hemocytes of mussels collected from December 2005 to September 2006. In both tissues mussels collected inside the Lagoon showed higher levels of DNA damage compared to specimens from the offshore site with a damage trend significantly increasing from the Lagoon border towards the inner part