Distribution of mercury in the organs and tissues of five toothed-whale species of the Mediterranean

Mercury levels were determined in the tissues and organs (lung, liver, kidn ey, skin, muscle, bone) of five toothed-whales stranded along the Corsican coast between November 1993 and February 1996. The species taken into consi deration were the bottlenose dolphin Tursiops truncatus, the common dolphin Delphinus delphis, the striped dolphin Stenella coeruleoalba, the pilot wh ale Globicephala melas and the Risso's dolphin Grampus griseus. The variati on in mercury levels between the different tissues and organs (lung, liver, kidney, skin, muscle, bone) of the cetacean species are discussed as regar ds storage, biotransformation and elimination. In all cases, the liver appe ars to be the preferential organ for mercury accumulation (with concentrati ons as high as 4250 mu g Hg/g dw and 3298 mu g Hg/g in the livers of Tursio ps truncatus and Grampus griseus, respectively). The kidney and lung are th e next organs in terms of mercury uptake followed by the muscle, bone and s kin. The stomach contents of Grampus griseus and D. delphis were determined and consisted of cephalopods for Grampus griseus, and of sardines Sardina pilchardus and mackerels Trachurus sp. for D. delphis. Cephalopods had high er mercury concentrations (25.4 mu g Hg/g dw) than fish (ca 1 mu g Hg/g). T hese contents represent only one meal and mercury levels found in livers ma y integrate mercury uptake having occurred during the whole life span of an imals. (C) 2000 Elsevier Science Ltd. All rights reserved.