Trends of PCB, hexachlorobenzene, and beta-benzene hexachloride levels in the adipose tissue of the U.S. population.

Results are presented on the levels of selected toxic chemicals in the adipose tissue of the U.S. population. Estimates of baseline levels and time trends are presented for the chemicals beta-benzene hexachloride (beta-BHC), hexachlorobenzene, and polychlorinated biphenyls (PCBs). The statistical analyses are based on chemical data obtained from analysis of tissue specimens collected from a nationally representative sample of autopsied cadavers and surgical patients by EPA's National Human Adipose Tissue Survey during the period 1970 through 1983. The results show that while nearly the entire U.S. population has detectable levels of these chemicals, the actual concentration levels of beta-BHC and PCBs are steadily decreasing and the levels of HCB are remaining fairly constant. Comparisons of levels across demographic subpopulations show that there are some differences in concentration levels across geographic regions, age groups, and race groups.