Organochlorine Pesticide Residues in Rainbow Trout, Oncorhynchus mykiss, Taken from Four Fish Farms in León, Spain

P. 779-786Chlorinated pesticides possess hígh chemical stability and strong lipophilic properties. Their use was restricted in Spain more than eighteen years ago, but they still exist as pollutants due to their occasional use and their persistence in the environment. Aquatic organisms, especially fish, can accumulate organochlorine residues directly from water through their respiratory processes and also from food. The residual levels detected in their tissues may reflect the environmental contamination. In this way, liver and kidney samples were used because they are the elimination organs for pesticides,and brain samples were selected because in this organ is where organochlorine toxicity is manifested. The main purpose of the present study was to establish the organochlorine pesticide contamination in rainbow trout (Oncorhynchus mykiss) taken from fish farros in León, in the North-West of Spain. Data obtained will provide sorne information about environmental contamination. Another objective was to investigate whether modifications in levels of these contaminants have occurred since 1987 by comparison with data obtained in a previous study carried out in trout, Salmo truttafario.S