Environmental factors promoting bioaccumulation of Hg and Cd in Antarctic marine and terrestrial organisms

Continental Antarctica is almost unaffected by long-range atmospheric transport ofheavy metals and contlIDination due te human activities has only been detected in very localised areas. Concentrations ofmetals in most abiotic environmental matrices are therefore among the lowest in the world. Despite these pristine environmental conditions, lichens, mosses and several anitnal taxa dominating coastal marine ecosystems of northern Victoria Land (continentaf Antarctica) .show surprisingly high concentrations of cadmium and mercury (i.e. similar to or higher than those measured in related . species in the northern hemisphere). Besides the slow growth rate (Le. long exposure time) and other ecophysiological characteristics ofAntarctic organisms, environmental factors such as upwelling of deep marine waters and ice-cover are presumably involved in the bioaccumulation of cadmium and mercury. These metals from the marine environment also reach cryptogarns in coastal ice-free areas through marine aerosol, seabird guano and snow precipitation. In coastal marine ecosystems, food webs are much more complex than the krill system in oceano waters. The involvement of benthic organisrns lengthens the chains and enhances the biomagnification of mercury (plankton < benthic invertebrates < demersal fish < fish-eating birds and mammals).