Directed transport of volatile organochlorine pollutants to polar regions: the effect on the contamination pattern of Antarctic seabirds

Polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) were analyzed in preen oil from birds from Antarctica, Sub-Antarctica and Europe. Antarctic and Sub-Antarctic birds contained unexpected high levels of volatile PCB-congeners and HCB compared to birds from temperate areas. This shows that the so-called cold-condenser effect causes concentrations of volatile organochlorine pollutants in Antarctic top-predators that are higher than in animals in more moderate climates close to the source of these pollutants. Antarctic top predators can be regarded as an utmost sink for volatile persistent pollutants. The levels of HCB indicate that seabirds from Sub-Antarctic regions are at risk to effects of organochlorine pollutants. Also Antarctic birds are potentially at risk, because of the high levels of HCB in combination with their extreme variability in physiological condition throughout the breeding season. When assessing the environmental impact of a contaminant this global effect should be of concern.