Over-salting roads and sidewalks potentially pollutes waterways

How much rock salt do you need to use?

As it turns out, you probably don't need to use as much rock salt to melt ice on your property -- and overuse is having some ill effects on the environment.

MINNEAPOLIS (FOX 9) - Winter is slowly leaving its mark on Minnesota and the arrival of snow and ice comes with an increased use of salt.

Unfortunately, the safety measure also puts fresh water at risk of collecting chloride, which is a permanent pollutant.

Scientists say just one teaspoon of salt or ice melt is enough to pollute five gallons of fresh water. But Minnesota agencies spread 445,000 tons — or about 255 billion teaspoons — on our roads every year.

The fish and plants growing in Thompson Lake will likely struggle more than most. The West. St. Paul waterway is one of 53 Minnesota lakes considered impaired by chloride — a problem that generally can only get worse.

"Once it's already in the system, we can't do anything to remove it," Brooke Asleson, a Minnesota Pollution Control Agency (MPCA) chloride specialist told FOX 9. "So we really want to prevent that from happening in the first place."

One of the easiest ways to protect Thompson Lake or Bde Maka Ska or any other fresh water is to not use too much salt or ice melt.

The MPCA says your best bet is shoveling first and using sand or grit on top of compacted snow to create traction.

They train public works departments across the state to do ice prevention by using brine – a combination of salt and water, which drastically cuts down on the need for salt.

"They've been able to reduce their salt use anywhere from 30 to 70% and still maintain safe conditions for the public," Asleson said.

"Tomorrow, before the storm, this will be out, anti-icing," Golden Valley Public Works Director Tim Kieffer told FOX 9, referring to one of their road maintenance trucks.

Golden Valley crews have their brine ready to go before the next storm. They’ve gotten the MPCA training and invested in technology giving them road temperatures and other data to help reduce the amount of chemicals they use while still keeping the roads safe.

"We're really trying to push liquids, reduce the granular salt," Kieffer said.

For those of us at home, they have this helpful measurement: just a coffee mug’s worth of salt should be enough to de-ice an entire driveway. And if you see leftover salt later, you can probably use less the next time around.