Bird feathers as bioindicators in areas of the German Environmental Specimen Bank--bioaccumulation of mercury in food chains and exogenous deposition of atmospheric pollution with lead and cadmium.

Feathers of selected bird species are used as pollution integrating biomonitors in areas of the German Environmental Specimen Bank. Lead, cadmium and mercury are analysed by Zeeman Solid Sampling AAS in feather vanes of selected bird species with different ecologies. In feather vanes there are quite different distribution patterns of lead and cadmium on the one hand and mercury on the other: lead and cadmium show strong gradients with respect to feather parts with high exposure to atmospheric influences. In contrast to this, mercury is distributed homogeneously. These different distribution patterns of lead and cadmium in feather vanes, in contrast to mercury, show that there are quite different incorporation paths. Cadmium and lead are deposited exogenously and indicate atmospheric pollution. Mercury in feathers is caused endogenously by food and physiology. Most of the mercury analysed in bird's feathers is in the ecotoxic methylated form and the contents in feathers depend on bioaccumulation in food chains. Feathers are suitable indicators for monitoring heavy metal pollution and give us information about incorporation paths and ecotoxic effects.