DISTRIBUTION OF HEAVY METALS IN ANTARCTIC MARINE ECOSYSTEM

Heavy metal concentrations in Antarctic surface seawaters and some marine organisms were determined, and their distributions and bioaccumulations were discussed in comparison with other marine ecosystems. Locational difference of the heavy metal concentrations in Antarctic seawater was negligible, and their concentrations were in the order of Zn - Fe> Mn> Cu>Pb - Ni> Cd> Hg. When compared to the western North Pacific, Japan Sea and Bering Sea, the concentra- tions of Fe, Zn, and Hg in Antarctic seawater were relatively low, which provides evidence that atmospheric transport of these metals from continents, either from natural or anthropogenic sources to the Antarctic water is much less. The Cd level was relatively high compared with those in the western North Pacific and Japan Sea waters, which might be due to the upwelling of Cd-enriched deep waters to the surface. In general, the heavy metal concentrations in Antarctic marine organisms were affected by the metal concentrations in the seawater. Also, it was found that bioaccumulations of metals in Antarctic marine ecosystem were characterized by a high accumulation of Cd and low accumulation of Hg, based on the short food chain with krill as key species, and also by a low accumulation of Fe in fishes as an adaptation to the cold water condition.