Road salt and icy winter: How do we balance safety and water pollution concerns? Live

Minnesota dumps some 730 million pounds of salt on roadways each winter, and it's posing a major risk to the environment. This winter, MPR News explores the issue and what's being done to address it.


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  • 4 earth-friendly tips to clean up your icy sidewalk

    The salt we're so inclined to dump on roads and sidewalks after winter storms is a growing threat to Minnesota's lakes and streams.

    Chloride — the mineral in salt that's toxic to fish, birds and other aquatic life — is now considered an impairment in 50 bodies of water across the state. Scientists only expect that number to rise.
    While large-scale salt application is the biggest culprit, there are some things individuals can do to minimize their impact. 
    Check out the tips on
  • Shingle Creek's cautionary tale for Minnesota's water

    Shingle Creek seen in Palmer Lake Park, Brooklyn Center, Minn. Photo by Tony Webster via Wikimedia Commons 2016
    Fifty Minnesota lakes and streams are now on the state's impaired waters list because of too much chloride, mainly from road salt. Excess chloride has widespread implications — everything from affecting aquatic life reproduction to corroding our infrastructure to health problems for humans.

    As scientists test more Minnesota lakes and streams, they expect to find more with salty problems.

    Shingle Creek was the first body of water added to the impaired list for too high a chloride concentration. But even 20 years of efforts to curb salt use around the creek haven't made much of a dent in the amount of chloride in the watershed, illustrating the long-lasting damage salt can leave behind.

    If you've ever driven Interstate 94 in the Twin Cities, you've probably driven over Shingle Creek. It starts in Brooklyn Park and winds southeast to Minneapolis, where it joins the Mississippi River. It drains almost 45 square miles of dense urban area crisscrossed with roads. Lots of roads.
    For the past 50 years or so, we've been using a lot of salt on those roads to melt ice and snow.

    "We've kind of brought this on ourselves a little bit because we have the capability to have very drivable roads in winter," said Ed Matthiesen, an engineer for the Shingle Creek watershed. "The downside is because we can get salt very cheaply and it's one of the things that keeps the roads clear, we tend to apply a lot of it."
    Beth Fisher and Patrick Hamilton, scientists from the University of Minnesota and the Science Museum, respectively, demonstrate how to test for salt levels in water as a preview to the pop-up winter salt lab. They also take viewer questions on Facebook Live. 
    by Michael Olson, MPR News edited by Cody Nelson 1/9/2018 7:31:50 PM
  • by Michael Olson, MPR News edited by Cody Nelson 1/3/2018 3:03:59 PM
  • 'Dead fish or dead people?' The challenges of curbing road salt use

    City of Minneapolis winter maintenance driver Vicky Stitch sits in the driver's seat of her snow plow in Minneapolis Dec. 11. (Evan Frost | MPR News)
    Virtually everyone agrees road salt is a necessary part of Minnesota's economy in winter. It keeps us safe and allows us to get to work.
    But scientists say also say that salt is a worrisome pollutant. Heavy road salt use over the past 20 years is causing many lakes in the metro area to show chloride levels that are dangerous to aquatic life. Statewide, 21 lakes, 22 streams and four wetlands have "unacceptable" chloride levels, according to the state Pollution Control Agency.
    About 10 years ago, Minnesota's winter maintenance leaders set targets for the minimum amounts of salt for various weather conditions that can keep drivers safe. The state is nowhere near reaching those targets.
    Still, some winter maintenance crews are trying.
    Read more on what the city of Minneapolis is doing on
  • Road salt is polluting our water. Here's how we can fix it

    Just a teaspoon of road salt pollutes 5 gallons of water — forever.

    And each winter, Minnesota dumps some 730 million pounds of salt on roadways.

    That's probably far more salt than we need to keep our roads safe.
    Once snow melts, salt flows into lakes and streams. Once salt is in a body of water, it's nearly impossible to remove.

    In fact, the only feasible way to clean up salt-contaminated water is through reverse osmosis, which remains too expensive to implement on a large scale.

    Chloride — the mineral in salt that contaminates waters — is toxic to fish, other aquatic life and birds. It can hurt pets and become a problem for groundwater.

    Corrosion from salt does a number on our infrastructure. According to a widely cited estimate from Ali Akbar Sohanghpurwala, an expert in the field of corrosion of metals in concrete, one ton of road salt does about $1,500 worth of corrosion damage to bridges, vehicles and environment.
    And keep in mind we use more than 300,000 tons of salt each year just in the metro area alone.
    Salt doesn't even work properly once temperatures dip below 15 degrees.

    Continue on to read some ways to cut salt pollution and remain safe in the icy, snowy months.
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