Congener-, isomer- and enantiomer-specific distribution of organochlorines in dippers ( cinclus cinclus L.) from Southern Norway

Abstract

To assess the contamination status of riverine environments in Southern Norway, dipper eggs from several locations were collected in spring 1993 and analysed for their content of α- and γ-hexachlorocyclohexane (HCHs), hexachlorobenzene (HCB), eight polychlorinated biphenyl congeners (PCBs), as well as the two toxaphene congeners Parlar no. 26 and Parlar no. 50. Since α-HCH is the only chiral isomer of all possible HCHs, enantiomer selective analyses of this compound were performed to find evidence for metabolisation processes in the birds. Results were compared with literature data from Ireland and Wales. The sum concentrations of DDTs and PCBs in liver and egg samples cover more than 90% of the total pollutant burden. The different patterns of the persistent pollutants in egg and liver samples are caused by differences in the matrix composition, especially the lipid content. The sum concentrations of the contaminants in eggs show higher average values than in liver samples. This indicates that the mother organism excrete lipophilic pollutants via eggs during the hatching period. Both liver and egg samples contain low concentrations of p,p′-DDT. The highest concentrations for DDT related compounds in egg and liver samples was found for p,p′-DDE. Higher enantiomeric excess of the (+)-α-HCH enantiomer in liver samples compared to egg samples were found. Differences in the distribution of pollutants in Norwegian dipper eggs compared to data from the British Isles (Wales and Ireland) are probably caused by differences in habitat and food sources.