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Feb 11, 2009 10:30 am US/Central
Report: Road Salt Accruing In Twin Cities Lakes
ST. PAUL (AP) ―
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While the researchers say the situation isn't an emergency, it has the potential to become one in a few decades.
CBS
Road salt runoff is slowly making lakes and wetlands in the Twin Cities saltier, according to a new report from the University of Minnesota.
The research team led by Heinz Stefan measured the salt content of 39 lakes in the metro area and found that the salinity increased over the last 24 years.
Their research found that 70 percent of the road salt applied to roads in the metro area stays in the area, instead of being flushed down the Mississippi River.
While the university researchers said the situation wasn't an emergency, it has the potential to become one.
"If we keep on doing this for another 50 years, we may have a significant problem," Stefan said. "Certainly if groundwater becomes saline, when we use that water we may have to treat it, at significant cost, by reverse osmosis, to remove that salt."
Reverse osmosis is the process used to get drinking water from the ocean.
Stefan said there's also a chemical reaction with heavy metals like lead and cadmium that come from vehicles to worry about.
"They're now in soils near roadways, and when chloride is added, these heavy metals are released from the soils, which means they go back in solution in the water and are then transported where we don't want them to be," he said.
Research has shown that salinity of several streams in the state already exceeds the state standard of about one teaspoon per five gallons of water. They include Minnehaha Creek, Battle Creek and Nine Mile Creek.
Kevin Gutknecht, a spokesman for the Minnesota Department of Transportation says the department is aware of the issue and is taking steps to reduce its use of road salt.
For example, highway crews often lay down a thin layer of salt before a storm, so ice doesn't get a chance to form in the first place. They also mix salt and sand with water so it will stick better. Updated equipment applies the salt more efficiently.
"It's an issue of better equipment, better training, better awareness," Gutknecht said.
Also, the Minnesota Pollution Control Agency has begun a training program to get road crews to use less salt. After training at the University of Minnesota, workers cut the amount of salt they used by 40 percent, saving $50,000 in one year, according to Brooke Asleson, who works in the MPCA's watershed program.
(© 2009 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)
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