Potential biomarkers of trichloroethylene and toluene exposure in Corbicula fluminea.

Freshwater clams Corbicula fluminea were exposed in aquariums to four doses of trichloroethylene-TCE-(1.56 up to 100 mg/1) or toluene-TOL-(7.5 up to 60 mg/1) for 5 days. At the end of exposure, components of (de)toxification metabolism of phases I and II, parameters related to oxidative stress and propionylcholinesterase activity were assayed. Determination of TCE and TOL concentrations in water revealed an important evaporative loss during the experiment, characteristic of acute and occasional contaminations by such products occurring in the environment. Appropriate statistical methods such as ANOVA, Tukey test and discriminant analysis underlined the relevance of cytochromes P450 and P418, NADH-cytochrome c reductase, catalase, peroxided and peroxidizable lipids and net peroxidation as biomarkers of exposure to these solvents in C. fluminea. This experiment emphasised the importance of a multi-biomarker approach in environmental surveys and will be completed further by mesocosm studies.