Guest Article form the Minnesota Pollution Control Agency (MPCA)
As the first snow of the season arrives, Minnesotans start thinking about clearing snow and ice from pavement — sometimes with salt. But when the snow melts or it rains, the salt, which contains chloride, runs into storm drains and into nearby lakes, rivers, and groundwater.
We scatter an estimated 365,000 tons of salt in the metro area each year. But it only takes a teaspoon of salt to permanently pollute five gallons of water. There’s no feasible way to remove chloride once it gets into the water, and we are finding increasing amounts of chloride in waters around the state. Salty water harms freshwater fish and other aquatic wildlife.
Though no environmentally safe, effective, and inexpensive alternatives to salt are yet available, smart salting strategies can help reduce chloride pollution in state waters. You might think more salt means more melting and safer conditions, but it’s not true! Salt will effectively remove snow and ice if it’s scattered so that the salt grains are about three inches apart (see this illustration for a visual reference. If you publish the graphic, credit the Regional Stormwater Protection Team). A coffee mug full of salt (about 12 ounces) is all you need for a 20-foot driveway or 10 sidewalk squares (roughly 1,000 square feet). Consider using a hand-held spreader to apply salt consistently, and use salt only in critical areas.
And sweep up any extra that is visible on dry pavement. It is no longer doing any work and will be washed away into local waters.
Additional tips for limiting salt use:
Learn more on the MPCA‘s Chloride webpage.
The Minnesota Pollution Control Agency recommends a low-salt diet for our lakes, streams, and rivers. Much like table salt, rock salt’s benefits are peppered with danger. Salt helps melt ice on roads and sidewalks. But when the snow melts, de-icing salt, which contains chloride, runs into nearby bodies.
There’s no feasible way to remove chloride once it gets into the water and salty water harms our freshwater fish and other aquatic wildlife. Learn more on the agency’s website at https://www.pca.state.mn.us/