THE USDA PERSPECTIVE ON DIOXIN CONCENTRATIONS IN DAIRY AND BEEF

The major dioxin-related research activities in the United States Depa rtment of Agriculture are 1) a survey of dioxin levels in beef samples collected at 13 experiment stations throughout the United States, 2) a feeding study of eight dioxins, four furans, and three PCB at levels equal to or above levels expected at highly industrialized locations, and 3) metabolism studies of C-14-labeled dioxin congeners. Prelimina ry results indicate that geographical location may influence dioxin co ncentrations in beef and that bulls may have concentrations higher tha n those in other slaughter animals. Metabolism of nontoxic congeners s eems to be rather complex, involving the arene oxide pathway, NIH type shifting of chlorine, and conjugation with sulfuric acid and glucuron ic acids.