Residents dig their cars out of the snow in Annandale, VA, on December 19, 2009. The runoff from deicers used to clear ice and snow from roadways and sidewalks can damage water supplies and ecosystems. This excerpted CAP guest post was first published here.
The winter season means holidays, vacations, and family time, but it also means the arrival of something else: snow. It may be beautiful as it’s falling, but dealing with the aftermath of a large snowstorm can be hard work. Ice and melting snow on sidewalks and streets creates hazardous conditions, but that doesn’t mean clearing it has to be harmful to the environment.
Chemical deicers such as sodium chloride, calcium chloride, and magnesium chloride are often applied to frozen roadways and sidewalks in rock salt form to make shoveling and clearing them easier after a big snow. The compounds form a brine solution that works by breaking down the molecular bonds that hold ice to cold surfaces, melting the snow as the reaction occurs. But as the brine continues to seep downward into the ground, the runoff is introduced into the ecosystem, which can damage surrounding grass, trees, and other plants before making its way back into the water supply, where it can cause further harm to plants, animals, and people who drink or use the water.
Studies on the effects of road-salt runoff in fresh water streams in Minnesota found that prolonged, high-dose exposure to the runoff was lethal for certain species of fish and insects. The studies also found that salts could damage or kill roadside grass, plants, and shrubs, all of which provide valuable ecosystems and erosion control. Excessive sodium levels in soil can change the soil’s chemical makeup and render it unable to retain water and therefore grow much of anything.
What’s more, these chemicals don’t just harm living organisms; the corrosive agents in road salts can damage and shorten the lifespan of roads, sidewalks, and other structures, creating the need for costly and nongreen-friendly replacement. One estimate places the costs of damage between $40 and $90 per ton of applied salt.
To minimize the damage done by chemical deicers, only use them in conjunction with snow removal. Shovel and sweep away as much snow as possible before applying deicer to your sidewalk or driveway, using the deicer only to break up the last layer of packed snow or ice. Mixing a half sand-half deicer recipe will minimize the amount of product needed as well as reduce the harm to the environment while providing traction and safety. Follow the instructions on the packaging to be sure you are not overapplying deicer and increasing the risk of harm to the environment.
Opt for a calcium magnesium acetate-based product since those formulas are salt free and have a lower likelihood of damaging plants and soil, as well as concrete surfaces. Other volcanic-based products are reusable and offer the same ice melting and traction properties without the harmful side effects, ensuring your grass and plants are around for holidays in the years to come.