Local officials not convinced mag chloride perfectly safe | AspenTimes.com

Local officials not convinced mag chloride perfectly safe

John Colson

Aspen area officials plan to continue to look into the potentialof harmful effects from the de-icer known as magnesium chloride,and state health officials are beginning to take notice of theissue.This is in spite of the apparent conclusion among state highwayofficials that the de-icer is safe to use on the state’s highways.At a meeting in Glenwood Springs on Wednesday, Colorado Departmentof Transportation officials cited a report by University of Coloradoresearcher William Lewis. It preliminarily concludes that magnesiumchloride does not harm aquatic environments such as rivers, streamsand wetlands.Lewis said at the meeting that he will not release the final reporton his three-year study for another six months. But in statementsexplaining the study’s methodology and the findings containedin an “interim report” dated April 1998, he indicated that magnesiumchloride does not pose a threat to rivers and streams near roadswhere the compound is used as a de-icer.Lewis based his findings, in part, on mortality studies of fourdifferent aquatic species – the boreal toad, rainbow trout, awater flea called Ceriodaphnia and a form of algae called Selenastrum.At the meeting he indicated that, because the chemicals appearnot to harm these species, they likely pose no significant threatto either the environment in general or human beings. But he alsosaid several times that he is not an expert in human health issues,and left it to others to study the effects of magnesium chlorideon human health.Pitkin County Environmental Health Department Director Tom Dunlop,who attended the Glenwood meeting, said Thursday that he feelsthat questions remain which Lewis and CDOT either failed to answer,or answered inadequately.Citing Lewis’ feeling that “if it’s not bad for the bugs, it’snot bad for us,” Dunlop said, “I’m not convinced it’s that blackand white. That’s too broadbrush a coverage for me.” He said hestill is concerned about the possibility of contamination fromheavy metals, including the potential for accumulation of heavymetals or magnesium chloride itself in the sediment on the riverbottoms.Lewis had found heavy metals – including arsenic, lead and cadmium- in early tests on CDOT stores of magnesium chloride. But subsequenttests showed that the levels had dropped to what officials believeare acceptable levels. Officials were at a loss to explain thephenomenon.Dunlop also expressed concern about the safety issues relatedto visibility on Highway 82 when magnesium chloride is used. Motoristshave complained that mag chloride puts a dense and dirty filmon their windshields that is difficult to clean off and makesdriving hazardous.The transportation department officials at the meeting essentiallybrushed off such questions, and Dunlop said he felt they madea mistake.”They have a public relations issue I think they’re ignoring,”he said, noting that if citizens are worried, it is the state’sjob to address those worries and either confirm that they arevalid or put them to rest.”I think there might be some more research that needs to be done,”he concluded.State health department officials will be testing Aspen’s air-qualitycontrol filters for heavy metals, along with filters from othertowns around the Western Slope, said Steve Arnold of the state’sair quality control division. As for further testing, he saidit will take a few months to determine whether the testing iswarranted, how it should be done and by whom.Local health department official Lee Cassin said she already hassent off a sample of the de-icer used in Aspen, and is awaitingtest results from the state to see if heavy metals are present.In the meantime, Cassin said she thinks the city should continueto avoid using magnesium chloride, except in relatively scantamounts and certain critical traffic situations, at least untilit is determined whether or not the city’s de-icer contains unacceptablelevels of heavy metals.The city’s streets department has cut back on the use of magnesiumchloride and returned to using more of a sand and salt mixturealong with a stepped-up plowing schedule. At present, magnesiumchloride will be used in high volumes only if the city’s air qualitydeteriorates because too much sand is being ground up by trafficand kicked into the air.Cassin agreed with Dunlop’s suggestion that the city also shouldconsider launching “a really strongly worded public awarenessprogram on how to drive in ice and snow.”

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