Trace elements in two odontocete species (Kogia breviceps and Globicephala macrorhynchus) stranded in New Caledonia (South Pacific)

摘要

Liver, muscle and blubber tissues of two short-finned pilot whales (Globicephala macrorhvnchus) and two pygmy sperm whales (Kogia breviceps) stranded on the coast of New Caledonia have been analysed for 12 trace elements (Al, Cd, Co, Cr, Cu, Fe, organic and total Hg, Mn, Ni, Se, V, and Zn). Liver was shown to be the most important accumulating organ for Cd, Cu, Fe, Hg, Se, and Zn in both species, G. macrorhynchus having the highest Cd. Hg, Se and Zn levels. In this species, concentrations of total Hg are particularly elevated, reaching up to 1452 μg g~(-1) dry wt. Only a very low percentage of the total Hg was organic. In both species, the levels of Hg are directly related to Se in liver. Thus, a molar ratio of Hg:Se close to 1.0 was found for all specimens, except for the youngest K. breviceps. Our results suggest that C. macrorhvnchus have a physiology promoting the accumulation of high levels of naturally occurring toxic elements. Furthermore, concentrations of Ni, Cr and Co are close to or below the detection limit in the liver and muscles of all specimens. This suggests that mining activity in New Caledonia, which typically elevates the levels of these contaminants in the marine environment, does not seem to be a significant source of contamination for these pelagic marine mammals.