title: Survey of dioxin-like compounds in dairy feeds in the United States.
abstract: The United States Environmental Protection Agency (USEPA) has completed a survey of dioxin-like compounds (including 17 dioxin and furan (CDD/F) congeners and 12 coplanar polychlorinated biphenyl (PCBs) congeners) in dairy feeds from 10 dairy research facilities around the United States, sampling the overall mixtures and the major and minor feed components. Low levels of dioxin were found in all feed mixtures with an average concentration of 0.05 pg/g (ppt) toxic equivalent (TEQ) dry weight. This is lower than previously found in dairy feeds by about a factor of 4. While it is possible that generally lower levels of dioxins in the environment in recent years may explain this result, examinations of the data suggest that the oven drying used to prepare the wet feed samples could have resulted in a loss of dioxins from the feed materials. The percentage of the total TEQ due to CDD/Fs was about four times that of PCBs. Leafy vegetations in the feed (the silages and the hays) had concentrations about twice as high as nonleafy, protected vegetation of the feeds (the ground or meal corn, cottonseed, and others). Minor components did not significantly influence the final feed mixture concentration of dioxin TEQ. However, in one of the feed mixtures, a minor component with a high concentration of 38.5 ppt TEQ effectively doubled the concentration of the overall feed mixture.
authors.affiliation: U.S. EPA, 1200 Pennsylvania Avenue, Washington, D.C. 20460, USA. lorber.matthew@epa.gov
authors.forename: Matthew
authors.initials: M
authors.lastname: Lorber
authors.forename: Dwain
authors.initials: D
authors.lastname: Winters
authors.forename: Joseph
authors.initials: J
authors.lastname: Ferrario
authors.forename: Christian
authors.initials: C
authors.lastname: Byrne
authors.forename: Christopher
authors.initials: C
authors.lastname: Greene
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D003612:Dairying; D003890:Desiccation; D004147:Dioxins / Q000032:analysis*; D005511:Food Handling / Q000379:methods; D006358:Hot Temperature; D018515:Plant Leaves / Q000737:chemistry; D011078:Polychlorinated Biphenyls / Q000032:analysis; D012820:Silage / Q000032:analysis; D014481:United States; D014484:United States Environmental Protection Agency
chemical_list: D004147:Dioxins; D011078:Polychlorinated Biphenyls