29 November 2007

Super high levels of dioxin in Michigan

Dioxin was the primary toxic component of Agent Orange, found at Love Canal, and at Times Beach.

Dow Jones Newswires reported a find of dioxin at the bottom of the Saginaw River could be the highest level of such contamination ever discovered in the nation’s rivers and lakes, according to a federal scientist involved in cleanup efforts downstream from a Dow Chemical Co. plant.

A crew testing the Saginaw and Tittabawassee rivers discovered the sample, which measured 1.6 million parts of dioxin per trillion of water, The Saginaw News and The Detroit News reported last week.

That level is about 20 times higher than any other find recorded in the EPA archives.

Michigan health officials were worried enough about last week’s announcement that they extended a fish consumption advisory already in effect for the Tittabawassee River—a Saginaw River tributary that winds through Dow’s plant in Midland—to include the entire Saginaw River and a portion of Lake Huron’s Saginaw Bay, where both rivers’ water ends up.

Dioxin is a general term that describes a group of hundreds of chemicals that are highly persistent in the environment.

The most toxic compound is 2,3,7,8-tetrachlorodibenzo-p-dioxin. Other dioxins use this form as a toxicity benchmark.

Dioxin is an unintentional by-product of many industrial processes involving chlorine such as waste incineration, chemical and pesticide manufacturing, and pulp and paper bleaching.