"Dioxins, Assessed At Last"

"After 21 years of contentious scientific analysis, the Environmental Protection Agency has established a safe level of exposure to the most toxic form of dioxin."



"EPA set a safe daily dose of 0.7 picograms of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) per kilogram of body weight. TCDD is the most potent congener of the dioxins, which generally are unintentional by-products of manufacturing processes involving chlorine and burning of biomass or waste.

Eventually, this defined level of safe exposure will affect the degree—and cost—of cleanups of soil and of industrial air and water releases polluted with dioxins. This category of chemicals consists of chlorinated dioxins and furans and certain polychlorinated biphenyls. These substances can trigger similar adverse health effects, but their potencies vary.

The exact regulatory impacts of the agency's determination, which was released on Feb. 17, are as yet uncertain. EPA's new level "will serve as the cornerstone of the agency's initiatives to protect public health from chemical contaminants and provide the necessary guidance to states and public health agencies to minimize dioxin exposure," says Olga Naidenko, a senior scientist with the Environmental Working Group, an activist group."

Cheryl Hogue reports for Chemical & Engineering News February 27, 2012.

Source: C&EN, 02/28/2012