National Academy of Science review of dioxin due today

Kathie Marchlewski, Midland Daily News

07/11/2006

State and federal agencies, local lawmakers, and stakeholders such as The Dow Chemical Co. and local environmental groups are set today to analyze a long-awaited scientific review of the Environmental Protection Agency's draft reassessment of dioxin.

Because of dioxin contamination in Midland and in the Saginaw Bay watershed, the stakes are high in the message provided by this expert review of the more than decade-long study by which the federal prescription for handling dioxin will be determined.

Dow, the EPA and the Michigan Department of Environmental Quality have been waiting for the National Academies' National Research Council report in hopes it will better define the toxicity of dioxin and dioxin-related compounds and that the expert opinion can be used to provide direction to remedy the dioxin problem here.

According to a report released in advance of an 11 a.m. press briefing today, the Academy did find some fault with the EPA's presentation of data, saying that certainties, assumptions and methodologies are not clearly identified.

"Failure to fully characterize uncertainty can convey a false sense of precision in the conclusions of the risk assessment," said committee chair David L. Eaton, a professor and associate vice provost for research at the University of Washington, Seattle. "EPA could improve the transparency and credibility of the assessment by more clearly identifying the assumptions used to support risk estimates and by updating them when significant new findings are made."

The Research Council committee was undecided on the question of whether there is enough evidence to classify dioxin as "carcinogenic to humans," but unanimously agreed that dioxin should be considered "likely to be carcinogenic to humans." It also noted that the choice is a question of semantics, rather than science, and said the health implications of the two classifications are identical.

Dr. Michael Harbut, a Royal Oak-based expert in environmental health, said an early review of the release indicates the report does nothing to change that "dioxin is still dangerous.

"Most informed physicians and scientists believe it causes cancer and a host of other serious health problems in humans, especially in unborn babies, who are the most vulnerable," he said.

The committee agreed with EPA's conclusion that dioxins probably are toxic to the human immune system, but it said the matter is not well enough defined. It said EPA should expand on its reassessment to discuss the biological mechanisms by which exposure to low doses of dioxins could compromise the immune system. It also suggested the agency more thoroughly address how developmental and reproductive harm caused by dioxins in animals could relate to human risks.

For those urging state and federal agencies to move along with cleanup of local dioxin contamination, the message in the report adds to their sense of urgency.

"The review is yet another piece of science strengthening the call for cleanup of the riverbanks and riverbeds downstream from Midland," said Terry Miller of the Bay City-based Lone Tree Council.

The report is expected to be available to the public today at national-academies.org.

See Wednesday's Daily News for reaction from government agencies and stakeholders, who are reviewing the report today.

©Midland Daily News 2006

For additional articles like this one, go to the Tittabawassee River Watch web site www.trwnews.net for complete coverage of the Tittabawassee River Dow Chemical dioxin contamination saga. . The Newspaper / Media page of our site contains an extensive archive of media articles dating back to January 2002. The source organization's web site link is listed to the right of the article, visit often for other news in our area. The Newspaper / Media page may be accessed by scrolling down to the bottom of the CONTENTS section and clicking on the Newspaper/Media link.