Relationship of silver with selenium and mercury in the liver of two species of toothed whales (odontocetes)

Liver specimens archived in the National Biomonitoring Specimen Bank from beluga whales, Delphinapterus leucas, and from Alaska and pilot whales, Globicephala melas, from the North Atlantic were analysed for silver, selenium and total mercury. Silver concentrations in beluga whales were one to three orders of magnitude higher than the concentrations in pilot whales and those reported elsewhere for other marine mammals. The concentrations of silver in the livers of beluga whales were the same or in some instances higher than the concentrations of selenium or mercury. Like mercury, silver was positively correlated with selenium in both pilot and beluga whales. This suggests a possible role for selenium in the accumulation and storage of silver in both species of whales, and raises questions about the potential for silver at such high concentrations to affect radical-scavenging enzyme systems in these marine mammals.