Making Deicers a Little Nicer

Rock salt and other deicers can pollute waterways and harm plants; consider these options to help keep your sidewalks less slippery this winter

  • Heidi Ridgley
  • Dec 01, 2004
Crossing a snow-covered Albany, New York, street, Jim Tierney wasn’t worried about slipping. He trusted the road-salting crews to keep the city from getting too slick. But as the state’s watershed inspector general on the lookout for substances that might harm water quality in New York, he voluntarily dropped to the pavement when he noticed a peculiar odor wafting up from the street. “It smelled like a college dormitory on a Sunday morning after somebody spilled beer all over the place,” says Tierney.

After a little investigating, he was pleased to learn the city was applying salt mixed with brewery sludge—a sticky concoction that reduces the amount of salt needed on slick streets. “When you lay down pure rock salt, it bounces all over,” he says. “It’s not good for the environment in the first place, but if you end up using more than you really need—whether you’re a city worker or a homeowner—that makes matters unnecessarily worse.”

Road salts might sound innocuous. After all, one variety is simply sodium chloride—better known as table salt. But in high concentrations the various ingredients in roads salts can stunt or kill plants and pollute rivers and streams through storm runoff—which ultimately can harm birds and fish, according to a recent study by the Canadian government. When spread by homeowners on sidewalks, such salts can damage soils and garden plants and also contribute to runoff pollution. A New York State study further found that the high phosphorus content of some deicers contributes to algae blooms, which deprives water of oxygen needed by aquatic animals and plants. In Colorado, salt is affecting the endangered cutthroat trout population, says Steve Glazer, a Sierra Club water expert in Crested Butte.

Manufacturers also sometimes add dangerous chemicals to keep salts from clumping together. “Magnesium chloride—one of the most popular choices—can contain a derivative of cyanide,” says Jeanne Prok of the Freshwater Society in Minneapolis. “That’s why it’s usually blue.”

The best option for the environment is to remove snow the old-fashioned way: with a shovel. Where deicers are needed, some experts recommend using sand or kitty litter instead. But in areas where sedimentation in streams is an issue, these, too, become problematic, says Prok, “unless homeowners take responsibility for sweeping them up before they run into area waterways.”

If you can’t get away from using a chemical deicer, look for liquid rather than granular forms that cover a larger surface. “It may cost more, but you don’t need as much,” says Malama Chock, coordinator of environmental management at the University of Michigan, which has reduced its salt use by 50 percent. She also recommends buying deicers made with corn or beet because they contain less chloride.

Anti-icing—applying deicers before the storm hits—is another recommended tactic. “It’s easier to remove snow before ice forms, and you’ll need less chemicals,” says Chock. Thinking creatively helps as well. “If you have multiple doors to your house, consider using only one in winter to avoid clearing other paths,” she says.

If you’re worried about how salt accumulation in the soil can harm your garden plants, Doug Kievit-Kylar of Vermont’s Agency of Natural Resources recommends erecting a physical barrier such as a burlap screen between your yard and the street so passing cars won’t spray salt onto plants. Another idea is to plant salt-tolerant vegetation near the road. “Your plants are more likely to survive, and they will help to absorb excess salt before it drains into local waterways,” he says. (Depending upon the region, native salt-tolerant plants include blue spruce, horse chestnut, red cedar, sumac, willow, black locust, redbud, hawthorn, walnut and dogwood.)

Ultimately, everybody should be mindful of how their daily lives affect waterways, says Jeannine Palms, who “adopted” a creek near her Ann Arbor home-based daycare. For 17 springs, she’s been taking the children in her care down to see the snow melt and gush into the creek. “It helps the children see the connection between how they live and how that affects the environment,” she says.

Several years ago, one of the children taught her a lesson back. “Very matter-of-factly a little girl asked me what we were going to do to stop all the salt from running into the creek,” says Palms. “Not having thought about it before, I asked her if she had any suggestions. She told me, ‘We need to talk to the boss of salt.’” On the surface, the directive sounds incredibly naive, admits Palms, “but in reality if you’re a homeowner with a sidewalk and a driveway, the boss of salt is you.”

Heidi Ridgley is associate editor of this magazine.

At a Glance 
Deicer Usage

If you must use a chemical deicer, you’ll end up needing less if it’s applied at the appropriate conditions outside. For example, magnesium chloride works to minus 13 degrees F and calcium chloride works to minus 25 degrees F. Best also to avoid products containing phosphorous more than 50 parts per million. 

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