ARCTIC MARINE MAMMALS AS INTEGRATORS AND INDICATORS OF MERCURY IN THEARCTIC

Mercury concentrations were determined in liver, kidney and muscle of belugas, narwhal, white-beaked dolphins, pilot whales, ringed seals, h arp seals and walrus. Tissue collections and analyses were performed l argely over the past 10 years. Sampling sites ranged across the Canadi an Arctic from the Mackenzie Delta and Banks Island in the west, Grise Fjord in the north, the Atlantic coast in the east and south. High Hg levels in the liver of ringed seals from the western Arctic, collecte d in 1987 and 1988 were similar to previously-reported values for ring ed seals collected in 1973 and 1972 from the same area. Comparison amo ng different marine mammal species showed substantial inherent differe nces in Hg levels among different species. White-beaked dolphins and w alrus had much less Hg than pilot whales. A comparison of Hg levels in ringed seals from locations across the Arctic and Hudson Bay showed t hat Hg was generally higher in ringed seals from the western than the eastern Arctic, indicating a possible influence of the different geolo gical settings in the eastern and western Arctic. The effect of age wa s considered in these comparisons. A similar, but less pronounced effe ct was noted for belugas, with some possible anthropogenic influence o n animals in Hudson Bay. The spatial trend in Hg levels in animals app eared to be largely present-day background concentration reflecting ge ological differences between the eastern and western Arctic, Higher Hg concentration were present in surficial sediments and coastal waters in the western Arctic than the eastern Arctic in accord with the Hg tr end observed in seals and belugas.