Whether you’re walking or driving to work, winter in Canada means braving icy, slushy, and snowy commutes. The first line of defence against snow and ice for many Canadians are road salts, and it’s not uncommon to see heavy amounts of salt coating streets and sidewalks. Environment Canada estimates that 5 million tonnes of road salts are used annually to keep Canadian drivers safe on the road, and this number doesn’t include the amount that homeowners purchase to deice their walkways and driveways. The problem is that road salts don’t break down, instead washing away and causing harmful chloride levels to build up over time in nearby soils, rivers, lakes, and even groundwater. Even when the snow finally melts and summer arrives, the lakes and waterways around cottage properties may still be feeling the effects from road salts used in wintertime.
For plants and animals that live in freshwater lakes and streams, an increase in chloride levels is bad news. Just like you couldn’t toss a freshwater species of fish like a smallmouth bass into the ocean and expect it to survive, studies suggest that rising chloride levels in freshwater environments can be dangerous for aquatic life. Research by the Toronto Region and Conservation Authority (TRCA) indicates that the amount of chloride in Toronto creeks is increasing year by year, while a 2016 study by TRCA staff showed that the abundance of aquatic invertebrates that are particularly sensitive to chloride decreased between 2002 and 2012.
For cottagers and waterfront property owners who enjoy swimming, boating, or fishing in cottage country, it’s important to consider the effects road salts can have. Christy Doyle, Director of Environmental and Watershed Programs with the Muskoka Watershed Council, says road salt “gets absorbed into roadside plants, licked up by wildlife, or accumulates in aquatic ecosystems.” High levels of salt in waterways can kill zooplankton, tiny living creatures that form the basis of aquatic food webs. Zooplankton will chow down on microscopic plants like green algae, otherwise known as phytoplankton. The loss of zooplankton could “inversely cause the amount of phytoplankton they feed on to go up, resulting in a loss of biodiversity and water clarity” says Doyle.
There are some best practices you can deploy to reduce the effects of road salt at your home or cottage. The Muskoka Watershed Council website recommends that before reaching for the bag of road salt, grab your snow shovel instead and clear as much snow and ice from your walkway and driveway as possible. If you do choose to apply road salt, remember that a little goes a long way: piling on layer after layer of salt won’t speed up the melting rate. You can also consider alternatives to road salt, such as sand. Some municipalities across Canada and the United States are trying innovative alternatives to road salt, including mixtures of beet juice, garlic salt, and cheese brine. By taking action in the winter to reduce the amount of salt runoff into the environment, you can help protect the water around your cottage property from salt pollution into the summer season and beyond.