Congener profile and toxicity assessment of polychlorinated biphenyls in human adipose tissue of Italians and Chileans

Human exposure to polychlorobiphenyls (PCBs) in humans was determined by an alyzing adipose tissue samples collected in 1996-1997 from two different lo calities: Siena (Italy) and Concepcion (Chile). Sigma PCBs was higher in It alian samples than that from Chile (493 and 53 ng/g wet wt., respectively). Thirty-seven different PCB congeners were identified in all samples. The p revailing PCB congeners in both groups were 22'44'5 pentachlorobiphenyl (IU PAC no. PCB 118), 22'344'5' (PCB-138) and 22'44'55' (PCB-153) hexachlorobip henyls and 22'33'44'5 (PCB-170), 22'344'55' (PCB-180) and 22'34'55'6 (PCB-1 87) heptachlorobiphenyls. PCB-153 accounted for more than 20% of the total PCB residue in both groups, while the remaining six congeners accounted for approximately 70%. Hexachlorobiphenyls were the most abundant congeners in all samples, with 42% of total residue in those from Italy and 43% in the Chilean samples, followed by heptachlorobiphenyls with 41 and 36% in Italia n and Chilean samples, respectively. Average concentrations of non-ortho su bstituted coplanar congeners were below 1 pg/g wet wt. In the samples from siena no noticeable differences were observed between the three average cop lanar concentrations, while in those from Concepcion 33'44'tetrachlorobiphe nyl (PCB-77) was much higher than 33'44'-pentachlorobiphenyl (PCB-126) and 33'44'55'hexachlorobiphenyl (PCB-169). For each sample the contribution to the total toxic equivalent values (Sigma TEQs) of each non-ortho, mono-orth o and di-ortho substituted PCB congeners was assessed. The overall TEQs cal culated for the monitored PCBs, were 10.16 pg/g wet wt, in Italian samples and 1.09 pg/g wet wt. in Chileans ones. In both groups the main contributio n to Sigma TEQs were the di-ortho substituted PCB congeners (Siena: 6.17 pg /g wet wt.; Concepcion: 0.56 pg/g wet wt.) and the mono-ortho substituted P CB congeners (Siena: 3.97 pg/g wet wt.; Concepcion: 0.50 pg/g wet wt.). (C) 2000 Elsevier Science B.V. All rights reserved.