Pilot study on the exposure of the German general population to non-dioxin-like and dioxin-like PCBs

In the past, polychlorinated biphenyls (PCBs) have been widely used and were distributed in the environment. Due to their high persistence and bioaccumulative potential, they can still be detected in the blood of the general population, despite their ban more than 20 years ago. Among the various congeners, the presence of dioxin-like PCBs in blood raises the highest environmental concerns due to their critical toxicological properties. We determined the plasma concentrations of 6 non-dioxin-like and 12 dioxin-like PCBs as well as the organochlorine pesticides HCB and p,p'-DDE (p,p'-dichlorodiphenyldichloroethylene) in a group of 105 non-smokers out of the German general population by GC/MS as an estimate of the background burden to these compounds. The organochlorine compounds were extracted from plasma with n-hexane, cleaned up on a silica gel column and finally quantified using GC/MS and (13)C(12)-labelled internal standards. The limit of detection for all congeners was determined to be 0.01 μg/Lplasma. Age had a strong influence on the plasma levels of HCB (hexachlorobenzene), p,p'-DDE and all higher chlorinated PCB congeners, while no gender difference was observed. Among the dioxin-like PCBs, PCB 118, PCB 156 and PCB 167 were detectable in 74-98% of all samples. Highly significant correlations between several PCB-congeners were observed. Our results provide for the first time volume-based data on the extent of the age-related background burden to dioxin-like PCBs in Germany.