Research at the University of Minnesota has revealed that road salt used throughout the winter is making the state's lakes and rivers saltier, which could affect aquatic life and drinking water. The research indicates that better training of snow plow drivers and more judicious use of road salt could help lessen the impact and save the state money.
To watch a video with research team leader Heinz Stefan, go to http://www1.umn.edu/urelate/newsservice/Multimedia_Videos/road_salt.htm
The researchers studied 39 lakes, three major rivers, 10 tributaries and numerous observation wells, and the results are alarming. They found that approximately 70 percent of the road salt being applied in the metro area is retained in our watershed. The university researchers recently reported their findings to the Local Road Research Board. Nearly 350,000 tons of sodium chloride, commonly referred to as road salt, are applied for de-icing in the Twin Cities metro area every year.
"Nobody has asked the question of where the salt ultimately goes after the winter season is over," said research team leader Stefan, a civil engineering professor at the university's St. Anthony Falls Laboratory. "Our study has been concerned with that question in particular."
Stefan's team (including Eric Novotny, Andrew Sander, Dan Murphy and Omid Mohseni) tracked the movement of chloride applied by humans throughout the water system, distinguishing it from geological or natural origins. They found that the chloride concentrations (salinity) in 39 metro area lakes have increased over the past 22 years, following a similar trend in road salt purchases by the state of Minnesota. Both show a marked increase from 1984 to 2005, which if continued would double salinity in these lakes in about 50 years. Compare this with a near zero concentration in the 1950s, when road salt application beg
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University of Minnesota