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Richard Maltby, 12/03/06, Letter to the editor, Saginaw News

Dioxin levels higher in region Sunday, December 03, 2006 Editor, The News:

Dr. Neill Varner says in his Nov. 17 letter, "Studying relative risks," that he appreciates the efforts of the University of Michigan dioxin exposure study team. "Their work, already recognized by the world scientific community, adds immensely to our understanding of the local dioxin burden of Saginaw and Midland county citizens exposed to dioxins along the Tittabawassee River."

How could that be? Other specialists have also expressed their opinions of the University of Michigan study.

Former Dow Chemical Co. engineer, and now manager of ChemTelligence Inc., David L. Linhardt tells us the dioxin exposure study team compared dioxin serum levels found in Michigan residents against levels measured by the National Health and Nutrition Examination Survey in 2000-2001.

To improve the validity of the comparison, the serum levels measured in 2000-2001 must be adjusted to 2005, the year in which the University of Michigan researchers sampled the blood of Michigan residents. It's believed that U-M did not adjust the cited level to year 2005.

Furthermore, on a year 2005 to year 2005 comparison, the median Michigan dioxin serum level measured by U-M is more than 70 percent higher than the national median, a difference much higher than the 10 percent elevation reported by U-M.

The U-M study also reported dioxin serum levels by other statistical parameters: mean, 95th percentile, and maximum levels. Based on these parameters, Michigan serum levels are 52 percent to 120 percent higher than the corresponding 2005 national survey levels.

Richard A. Maltby

Midland

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