As the first major snow of the season arrives, Minnesotans are thinking about clearing snow and ice from pavement - sometimes with salt. 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.
The Minnesota Pollution Control Agency (MPCA) 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 and protects drivers and pedestrians. But when the snow melts, de-icing salt, which contains chloride, runs into nearby bodies of water and harms aquatic wildlife. Chloride accumulates in the water over time, and there's no feasible way to treat or remove it.
A University of Minnesota study found that about 78 percent of salt applied in the Twin Cities for winter maintenance ends up either in groundwater or local lakes and wetlands. The MPCA has found that groundwater in the state's urban areas often exceeds the state standards for chloride contamination. Forty-seven bodies of water in Minnesota have tested above the standard for chloride, 39 of which are in the Twin Cities metro area.
Though no environmentally safe, effective, and inexpensive alternatives to salt are yet available, smart salting strategies can help reduce chloride pollution in state waters, while saving money and limiting salt damage to infrastructure, vehicles, and plants.
Do your part by following these simple tips:
• Shovel. The more snow and ice you remove manually, the less salt you will have to use and the more effective it can be.
• 15 degrees (F) is too cold for salt. Most salts stop working at this temperature. Use sand instead for traction, but remember that sand does not melt ice.
• Slow down. Drive for the conditions and make sure to give plow drivers plenty of space to do their work. Consider purchasing winter (snow) tires.
• Apply less. More salt does not mean more melting. Use less than four pounds of salt per 1,000 square feet. One pound of salt is approximately a heaping 12-ounce coffee mug. Leave about a three-inch space between granules. Consider purchasing a hand-held spreader to help you apply a consistent amount.
• Sweep up extra. If salt or sand is visible on dry pavement it is no longer doing any work and will be washed away. Use this salt or sand somewhere else or throw it away.
• Hire a certified Smart Salting contractor. Visit the MPCA web site for a list of winter maintenance professionals specifically trained in limiting salt use.
• Watch a video. Produced by the Mississippi Watershed Management Organization, it offers tools for environmentally friendly snow and ice removal.
• Act locally. Support local and state winter maintenance crews in their efforts to reduce their salt use.
• Promote smart salting. Work together with local government, businesses, schools, churches, and nonprofits to find ways to reduce salt use in your community.