Analysis of HO-PCBs and PCP in blood plasma from individuals with high PCB exposure living on the Chukotka Peninsula in the Russian Arctic

Summary

A trace analytical method is presented for the analysis of hydroxylated polychlorinated biphenyl metabolites (HO-PCBs) and pentachlorophenol (PCP) in human plasma. The described methodology is a modification of a previously validated method used for PCB and organochlorine pesticide analysis. The modified method enables the combined analysis of phenolic and neutral halogenated compounds. A tandem Florisil column is used for separating the HO-PCBs and PCP from the neutral fraction, instead of the more common chemical partitioning. In the same step the neutral fraction is purified for GC analysis. The extraction of the HO-PCBs and PCP was found to be highly dependent on sufficient acidification of the sample and the polarity of the extracting solvent. Analysis of plasma samples gave recovery rates for C-13(6)-PCP and C-13(12)-4- HO-CB 187 of 64 and 72%, respectively. The limit of detection ranged between 2 - 20 pg g(-1) plasma for the HO-PCBs and 5 pg g(-1) plasma for PCP. No matrix interferences were observed in the chromatograms. In plasma samples ( n = 15) from the native Chukchi people in Uelen (Russian Arctic), a population with high PCB exposure, the median ratio of sum HO-PCBs to sum PCBs was as high as 0.4 and the sum HO-PCBs and PCBs were significantly correlated (r(2) > 0.7, p < 0.01). The median sum HO-PCBs (10 congeners) was 5920 pg g(-1) plasma with 4- HO-CB 107 as the dominating congener ( median: 1670 pg g(-1) plasma). The median PCP level was measured at 642 pg g(-1) plasma.