MINNEAPOLIS (WCCO) — It’s a difficult balance: keeping our roads and sidewalks clear of ice, while not harming our environment.
With all of the snow and ice that’s come down this winter, that dilemma had Jay Christopherson from Hutchinson wondering: Are there any good alternatives to salt? Good Question.
“Most of our storm water drains into the Crow River,” says Christopherson. “I’m concerned about what I’m putting into the river.”
According to the Minnesota Pollution Control Agency, he should be concerned. Salt is mostly sodium chloride and it’s the chloride that’s toxic to fish and insects living in lakes and streams.
“I think everyone just wants there to be some easy fix to this problem,” says Brooke Asleson, MPCA’s water pollution prevention coordinator, “There’s not an easy solution, unfortunately.”
But, there are some imperfect options. Some states and municipalities have tried substances like cheese brine or beet juice. Those products need to be mixed with salt to work, but require less of it.
MnDoT says it tried beet juice a few years ago, but found a liquid brine mixture worked just as well.
MnDoT is also currently testing a chemical called potassium acetate on roads in northern Minnesota. It’s more expensive, but crews don’t have to use as much of it to work. Potassium acetate is still toxic to fish and insects, but it appears to break down over 48 hours. Chloride, for the most part, lasts forever.
Products like kitty litter and coffee grinds provide temporary traction, but won’t melt the ice. Salt melts the ice because it changes the temperature at which the water freezes.
“Right now, we have a three-way balance — public safety, cost and the environment,” says Mike Kennedy, director of winter operations for the City of Minneapolis. “Salt is the most plentiful and cost-effective substance in the industry right now.”
Asleson understands an individual’s need for safety, and says salt is appropriate if used in the right amounts and conditions. Sodium chloride won’t work if it’s too cold and there’s no need to spread it in temperatures below 15 degrees.
The MPCA offers this rule of thumb when it comes to applying salt: one cup for every 250 square feet. That equals about two public parking spaces. It should be one grain of salt for every 3 inches.
And once the ice melts, Asleson says, “There should be no sign of salt, then you’ll know you have the right amount of salt.”
She also recommends using a liquid brine mixture, which can reduce salt usage by 50 to 70 percent. It allows the salt to work more quickly and prevents it from simply washing away.