Integrated use of antioxidant enzymes in mussels, Mytilus galloprovincialis, for monitoring pollution in highly productive coastal areas of Galicia (NW Spain).

In the present work, we investigated the potential use of several antioxidant enzymes in wild mussels (Mytilus galloprovincialis) as biomarkers of marine pollution. The enzymatic activity levels of glutathione S-transferase (GST), glutathione peroxidase (GPx) and catalase (CAT) were measured in gills and digestive gland. Those enzymes participate in the cellular defense system that is involved in the adaptive response of organisms to chemical pollution. Adult mussels were collected at five sampling sites located at the Ría de Pontevedra and Ría de Vigo. Seasonal variations in the control site were observed for the CAT activity, but no significant variability was found for GST and GPx. Mussels from the most polluted sites exhibited a significantly greater GST activity compared to the control site (p<0.05) during the sampling period, whereas GPx and CAT activities have not such a marked pattern. Trace metals, PAHs, PCBs and DDT contents in mussels at sampling sites showed highly significant positive correlations with the GST activity. This study supports the use of GST as a useful biomarker for long-term pollution monitoring in marine coastal ecosystems, whilst more research is needed for GPx and CAT.