Analysis of hydroxylated metabolites of PCBs (OH-PCBs) and other chlorinated phenolic compounds in whole blood from Canadian Inuit

In this study, we identified the main hydroxylated polychlorinated biphenyl s (OH-PCBs) and other chlorinated phenolic compounds and we determined thei r relative concentrations in whole blood from 13 male and 17 female Inuit f rom northern Quebec, Canada, and from a pooled whole blood sample from sout hern Quebec. We also determined concentrations of polychlorinated biphenyls (PCBs). Total OH-PCB concentrations were variable among the Inuit samples, ranging over 2 orders of magnitude (0.117-11.6 ng/g whole blood wet weight ). These concentrations were equal to and up to 70 times those found for th e southern Quebec pooled whole blood sample. Geometric mean concentrations of total OH-PCBs were 1.73 and 1.01 ng/g whole blood for Inuit men and wome n, respectively, and 0.161 ng/g whole blood for the southern population poo l. There are limited data available for comparison, but the levels of OH-PC Bs in Inuit are higher than those previously reported in the literature for other populations. There was a significant correlation (p < 0.005) between OH-PCBs and PCBs (r = 0.84) and both correlated significantly (p < 0.005) with age (r = 0.68 and 0.78, respectively). The ratio of OH-PCBs to PCBs wa s lower in Inuit (0.11) than in the southern Quebec pool (0.33). There is n o apparent explanation for the difference. There was considerable variabili ty in the congener pattern of the identified OH-PCBs. The main metabolite, 4-OH-CB109 (4-OH-2,3,3',4', 5-pentachlorobiphenyl), constituted 12-62% of t he total OH-PCBs in the samples. Pentachlorophenol (PCP) was the dominant p henolic compound in blood, constituting 46% (geometric mean) of the total q uantitated chlorinated phenolic compounds. PCP concentrations in Inuit bloo d ranged from 0.558 to 7.77 ng/g on a wet weight basis. All but two Inuit s amples had lower concentrations than the southern Quebec pool (6.29 ng/g). The possible role of OH-PCBs in mediating PCB-induced adverse effects needs to be investigated further.