Contamination Profile and Temporal Trend of POPs in Antarctic Biota

The continent of Antarctica is a cold desert surrounded by the Southern Ocean; its northern boundary is the Antarctic circumpolar current (ACC), commonly referred to as the polar front. The ACC is formed where cold seawaters sink beneath the northerly warmer waters. It acts as a biological barrier: organisms are not able to cross it because of the deeply different physicochemical properties of seawaters. Thus, only large animals can cross it (cetaceans, seabirds). The atmosphere over the southern hemisphere shows also a polar front where the Ferrell Cell (mid-latitude air circulation) meets the polar cell: in the former, the air flows toward the poles and eastward near the surface and equatorially and westerly at higher altitudes. At the front, air rises and travels towards the pole, where it sinks forming the polar highs. The Antarctic continent and the Southern Ocean are almost isolated from the other oceans and air masses and thus the turnover is very low. These geographical and air/ocean circulation features make this region of the planet difficult to be reached by persistent organic pollutants (POPs). At the same time, other characteristics of the continent and of the Southern Ocean affect the sinking and bioaccumulation of POPs in abiotic and biotic compartments of Antarctic ecosystems. © 2012 by Taylor & Francis Group, LLC.