ENANTIOMERIC SIGNATURE OF CHIRAL POLYCHLORINATED BIPHENYL ATROPISOMERS IN A BENTHIC FOOD CHAIN

Abstract

Sediment, polychaeta and flatfish were collected from Masan Bay, Korea in December 2004 and May 2005. Muscle, liver and stomach content of flatfish, polychaeta, and sediment were analyzed for polychlorinated biphenyls (PCBs) concentrations and the enantiomeric fractions (EFs) of six chiral PCB congeners (CBs 91, 95, 136, 149, 174, and 176) to quantify enantiomer-specific accumulation of PCBs in the benthic environment of the bay. Stomach content and stable isotope of carbon and nitrogen were analyzed in samples and used to confirm the prey and predator relationship between them. The total PCB concentrations in the samples clearly showed that PCBs are biomagnified in higher trophic level organisms. The congener pattern of chiral PCBs are similar to between the benthic food chain members, however, they had different chiral signatures, indicating that PCBs were accumulated enantioselectively through the food chain. The change of chiral signatures of chiral PCB atropisomers in the benthic food chain of the bay can be summarized as follows: CB 91, E2 to racemic; CB95, racemic to E1; CB 136, racemic to (-)-enantiomer; CB 149, (+)-enantiomer to racemic; CB 174, racemic to racemic.