Chaine trophique experimentale en milieu limnique: Contaminations directe et trophique d'un consommateur de 3ème ordre (Salmo gairdneri) par le methylmercure

Within the context of ecotoxicological research on an experimental trophic chain, the analysis of tissue spread of Hg with Salmo gairdneri, after global contamination by methylmercury, brings out a clear preponderance of bioaccumulated metal of a trophic origin. This is all the more visible as the length of time for the experiment and the temperature of the environment are higher (18°C and 30 days). After global contamination, various kinds of organs can be distinguished according to Hg concentration and to the effect of abiotic factors on accumulation processes: Brain and muscles: their ecotoxicological behavior is the same as that of the whole fish; Hg tenors are fairly low but their increase is quite significant when the temperature of the environment and contamination time are higher. Posterior intestine: the high Hg concentrations and the high retention capacity make it an accumulation organ. After 30 days' experimenting the trophic contribution represents over 95 % of the Hg in that organ. Gills: contrasting with the intestine gills are characteristic of direct contamination. Their metal concentration are fairly independent of environmental temperature and length of time. Figured elements and liver: they present the highest Hg concentrations; as with gills, the influence of experimenting time is slight.