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Neil Varner 11/18/04

Dioxin effect no so clear

Editor, The Saginaw News:

The flurry of media reports on the unfolding dioxin story (Dow study bolsters health claims," Nov. 10; "Dow study legitimate, but limited," Nov. 12, and Howard Steinmetz"s letter, "Think about it", Nov. 11) call for some additional reflection and comment.

The remarks attributed to Anne Ainsworth regarding the lack of evidence for health effects among workers whose exposure was high compared to the residents of the Tittabawassee River, in which she stated that it is "reasonable to assume that it would be difficult to find health effects of dioxin in a group of less exposed people" reflects, in my view, a poor understanding of the dose response mechanism that describes dioxin congeners effects.

It has been shown that many of the effects of dioxin exposure occur in a non-monotonic fashion. In other words, the dose-response curve behaves oddly, with some health effects occurring at very low level exposures, while those same effects disappear at higher doses.

On the other hand, to live one's life fearful that cancers that have claimed some of those residents (Ron Wilkins and Dr. Herbert Buchalter) whom we all have come to know, love, and respect, are caused by their exposure to the dioxins, furans, and co-planar PCB's found in the Tittabawassee soil is without warrant.

While "absence of evidence is not evidence of absence," we cannot and must not conclude that all cancers in people living in the floodplain are due to dioxins, as implied by Steinmetz's reference to the "poisonous environment that we are living in."

Dr. Neill D. Varner

medical director

Saginaw County Department of Public Health



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