Congener specific determination and enantiomeric ratios of chiral polychlorinated biphenyls in striped dolphins (Stenella coeruleoalba) from the Mediterranean sea

Blubber and liver samples from six striped dolphins (Stenella coeruleoalba) found dead in the Mediterranean sea in 1989-1990 were tested for 37 coplan ar and chiral polychlorinated biphenyls (PCBs), including the enantiomeric ratios of 9 chiral PCBs. The method includes a fractionation step using HPL C (PYE column) for separating the PCBs according to the number of chlorine atoms in the ortho positions. HRGC/ECD and HRGC/LRMS with an achiral column (DB-5) were used to determine the PCB congeners. The enantiomeric ratios o f nine chiral PCBs were determined by HRGC/LRMS (SIM) with a chiral column (Chirasil-Dex) and by MDGC as the confirmatory technique. The total PCB con centration (sum of 37 congeners) ranged from 7.2 to 89.6 mu g/g (wet weight ) and from 0.52 to 29.2 mu g/g (wet weight) for blubber and liver samples, respectively. PCB profiles were dominated by congeners 138, 153, 170, and 1 80. The toxic equivalent values (TEQ) ranged from 0.17 to 3.93 ng/g (wet we ight) and from 0.02 to 0.73 ng/g (wet weight) for blubber and liver samples , respectively. PCBs 95, 132, 135, 149, and 176 revealed an enantiomeric ex cess of the second eluted enantiomer in almost all of the samples, whereas PCBs 136 and 174 were racemic or almost racemic. PCBs 88 and 91 were under the detection limits of the methodology used.