Concentrations of 24 individual PCB congeners have been measured in livers of groupers (Epinephelus marginatus) and eight shark species (Centroscymnus coelolepis, Centrophorus squamosus, Dalatias licha, Hydrolagus affinis, Deania profundorum, Centroscymnus cryptacanthus, Etmopterus princeps, Deania histricosa) collected between 1994 and 1995 from the northwest African Atlantic Ocean. The concentration range of the total PCBs was 39.4-4,723 ng/g (wet weight). The TEQs found were between 0.15 and 197 pg/g (wet weight). Analysis has revealed differences in PCB content and PCB profiles among the eight shark and grouper species. The location and depth at which the shark lives and the liver lipid content were related with their PCB liver concentrations. The PCB profiles were dominated by congeners 138 and 153, and among the most toxic congeners the order of abundance was PCB 77 > 126 > 169. Chiral PCBs 95, 132, 136, 149, and 174 were found to be racemic or nearly racemic in almost all the groupers (E. marginatus) studied. The PCB profiles of shark species and groupers were compared by principal component analysis. Samples were separated into groups according their trophic levels and geographical variations.

SummaryChiral2,2',3,5',6-pentachlorobiphenyl (PCB 95),2,2',3,3',4,6'-hexachlorobiphenyl (PCB 132) and 2,2',3,4',5',6-hexachlorobiphenyl (PCB 149) were quantified in Atlantic Ocean shark liver samples (C. codolepis) by gas chromatography-mass spectrometry (GC-MS) and their enantiomeric ratios were studied by multidimensional gas chromatography (MDGC) with an achiral-chiral column combination and detected by ECD and MS/SIM. The concentration range of the chiral PCBs was from 2 to 6 ng/g (fresh weight), which represents 2-6 % of the total PCB mean concentration. The investigations revealed a small enantiomeric bias of PCB 132 in most of the samples studied (ER = 0.75-0.89, ee = 6-14%), while PCB 95 and PCB 149 were present in racemic or almost racemic form.

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