Mag chloride expert short on answers
April 3, 2002
Everyone exercised constraint in Aspen City Council chambers yesterday, when one of the foremost experts in the state on magnesium chloride addressed the public.
Just about every seat in the room was filled, and it was clear that a number of those present had a litany of questions they wanted to ask Dr. William Lewis, a professor of environmental sciences at the University of Colorado.
The problem was he couldn’t answer their questions.
Lewis, a limnologist by training, has conducted three studies on magnesium chloride for the Colorado Department of Transportation, although only one was on the actual effects of magnesium chloride on the environment.
Lewis was in town at the invitation of the Pitkin County Public Works Department to answer at least some of the questions that have been bubbling up during the last several magnesium chloride seasons.
Magnesium chloride is a salt cousin of sodium chloride, the rock salt that’s used to flavor meat on dinner tables throughout America and melt ice in the Northeast. It has been CDOT’s favorite way of melting icy roads since the mid-1990s, with six million to eight million gallons of the stuff being sprayed on mountain highways – including Highway 82 – each year.
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Lewis’ work for CDOT has included a survey of scientific literature on magnesium chloride, a study of its effects on aquatic life and a comparative study of alternatives to the de-icer.
Most of what Lewis discussed yesterday involved his study on mag chloride’s effects on aquatic life. The study, conducted between 1996 and 1998 along the I-70 corridor, concluded that four aquatic species were unaffected by the mag chloride that made its way from the road to the stream, primarily because of dilution.
He reiterated those findings yesterday, even though many of them came from a stream that is located much further from I-70 than the Roaring Fork River is from Highway 82.
Several local residents who have reservations about magnesium chloride were in the room, but were limited to questions that had to do with Lewis’ academic specialization of limnology, the study of bodies of freshwater. By the end of the meeting, it was clear that the room’s anti-mag chloride bias, and the questions that resulted, were wearing down the professor’s patience.
Lewis’ own biases came out early in the discussion when he refused to admit that magnesium chloride has killed pine trees along I-70 that have been declared dead by numerous wildlife and environmental experts. Lewis said only the exposed portions of the tree die, which makes them “look dead.”