Multimarker approach in transplanted mussels for evaluating water quality in Charentes, France, coast areas exposed to different anthropogenic conditions.

An active biomonitoring experiment was performed using mussels collected at a clean site, Fier d'Ars, and transplanted to two locations, outside the harbor of La Rochelle and in the Baie de L'Aiguillon along the coast of Charentes (French Atlantic coast) beginning in April for several months. Mussels were collected in June and October. The cadmium, copper, and zinc concentrations of all resident and transplanted mussel samples and the polycyclic aromatic hydrocarbon and polychlorinated biphenyl concentrations in some mussel samples and in the sediment samples were determined. Mussel response was evaluated for several biochemical biomarkers: concentrations of metallothionein, activities of glutathione S-transferase and acetylcholinesterase (AChE) and levels of thiobarbituric reactive substance (TBARS). The physiological status of the animals was assessed using the condition index. A principal component analysis performed with the chemical and biochemical results of the evaluations of the resident and transplanted mussels collected in June allowed them to be separated into three groups: resident mussels from la Rochelle with high metal and TBARS levels, resident mussels from Baie de L'Aiguillon with a very high condition index, and resident mussels from Fier d'Ars and transplanted mussels at La Rochelle and Baie de L'Aiguillon with low TBARS and AChE activities. Strong seasonal variation from June to October of all parameters was noted. Mussels transplanted to La Rochelle appeared to be the most "polluted" in their pollutant concentrations and biochemical responses; moreover, the La Rochelle site had the highest concentration of organics in sediments of all the sites. The choice of Fier d'Ars as a reference site may be questionable because some of the biomarker responses of the mussels were higher than expected there, although these pollutants in mussels and sediment were present at the lowest concentrations measured.