The contamination of birds with organic pollutants in the Lake Baikal region

Lake Baikal is considered to be the largest reservoir of fresh natural water in the world. Nevertheless industrial enterprises on its banks as well as river effluents contaminate this unique basin. In the present study birds' eggs (15 species) collected in the Baikal region (Selenga river estuary) have been analysed. Quantitative determination of more than 40 individual organic pollutants (polycyclic aromatic hydrocarbons, phenols, organochlorine compounds) has been carried out using GC-MS as an analytical tool. The results obtained demonstrated a wide range of toxicant concentrations (2-3 orders of magnitude) for various species. Very high levels of polycyclic aromatic hydrocarbons have been detected in the eggs of Anas platyrynchos (mallard), Tringa stagnatilis (marsh sandpiper) and Podiceps auritus (slavonian grebe). These particular species also have the highest levels of other toxicants. Taking into account high rate of metabolism of certain of these compounds in birds, it has been proposed that the major route of transfer into higher trophic levels is via water and aquatic invertebrates.