Enantioselective analysis of organochlorine pesticides in herring and seal from the Swedish marine environment

Factors influencing the changes of enantiomeric ratios (ERs) in herring (Clupea harengus), grey seal (Halichoerus grypus), harbour seal (Phoca vitulina) and ringed seal (Phoca hispida) collected along the Swedish coastline were studied by enantioselective high-resolution gas chromatography (HRGC). Three-year-old male and female herring individuals from different sampling sites were selected, whereas seal blubber and liver samples represented different species, sexes and geographical locations. Enantioselective analysis of α-hexachlorocyclohexane (α-HCH), chlordanes and chlordane metabolites were performed. In general, herring showed similar ERs within the Baltic Sea. Results indicate that species specific differences are important factors controlling the ERs of Baltic seals. Inverse ERs in seal blubber and liver, and a low deviation from the racemic ratio of some components in the liver, indicate that not only enantioselective degradation but also stereoselectivity of other processes are responsible for the changes of ERs in biota.