Background levels of non-ortho-substituted (coplanar) polychlorinated biphenyls in human serum of Missouri residents

This study characterizes the levels of polychlorinated biphenyls (PCB) cong eners PCB 77, PCB 81, PCB 126, and PCB 169, in a group of 150 men and women with no documented exposure to PCBs, Its purpose is to provide current ref erent levels of coplanar PCBs in Missouri residents and to compare those le vels to levels reported in the literature from the United States and other countries. Although this study used an extensive questionnaire assessing po tential sources of exposure, no positive relations were found between these exposure sources and participants' PCB levels. The PCB levels for the four congeners measured were lower than any reported in the literature. PCBs 12 6 and 169 are only two of the dioxin-like congeners, however, their contrib ution makes up 11% of the total TEQ. Age was significantly related to PCB 1 26 and PCB 169. For every one-year increase in age, both PCB congeners incr eased by approximately 0.4 parts per trillion (ppt), There was no gender di fference for PCB 126; however, PCB 169 levels were 3 ppt higher in males th an females. (C) 2001 Elsevier Science Ltd. All rights reserved.