EVOLUTION OF THE METALLIC CONTAMINATION OF THE STRIPED DOLPHINS (STENELLA COERULEOALBA) ON THE FRENCH MEDITERRANEAN COASTS BETWEEN 1990 AND 1997

摘要

As part of a program monitoring the contamination of Cetaceans by heavy metals on the French Mediterranean coast, the levels of cadmium, copper, mercury, nickel, lead and zinc in nine striped dolphins (Stenella coeruleoalba), stranded dead on the beach in 1996 and 1997, have been worked out. The results obtained were compared to those of a similar study carried out in 1990 and 1991 on the same species. A significant decrease in the concentrations of copper, mercury, nickel and lead was shown, as well as a slight decrease in the concentrations of cadmium. Contamination by zinc was not lower and remain rather high. These results are most likely the consequence of the efforts made to clean up the coast, inadequat as it may be. Indeed, the metallic contents of the most contaminated dolphins still remain high and pose a toxicological problem which is discussed, with emphasis on mercury. Cetacean are reliable biological indicators and irrefutable evidence of the chronical poisoning of the sea and of the danger of high concentrations of some pollutants in the food chains.