Road Salt Is Toxic And Should Be Regulated
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Road Salt Is Toxic And Should Be Regulated

Each winter, more than 120,000 tonnes of salt is dumped on Toronto pavement.

Road salt_bus

Road salt is devastating for the city’s buildings, infrastructure and wildlife, not to mention clothes and our pet’s paws. Torontoist Flickr photo courtesy of user Benjamin Moogk.

Nearly every surface of the city was slick with ice when Angela Wallace left home to pick up her children after school on February 7. She was careful as she walked down her stairs but slipped on the final step, striking the back of her head on a wall. Suspecting a concussion, her worries were confirmed in the emergency room. 

Accidents like Wallace’s are a top concern for property owners fearful of being sued for slip and falls on their icy premises. For that reason, many use exorbitant amounts of road salt to avoid legal repercussions.

Indeed, keeping sidewalks and roads cleared is critical for the safety of all pedestrians and drivers in the city. But even Wallace, a project manager with Toronto and Region Conservation, will argue that we are collectively overdoing it.

Every year, more than 120,000 tonnes of salt is dumped on Toronto pavement. And the impact of that sodium chloride, once the ice and snow melts away, can be devastating to our city’s natural and built environments.

Heavy salt use corrodes steel and rebar inside concrete buildings, it damages asphalt, and is deemed a main culprit behind the crumbling state of the Gardiner Expressway (to say nothing of the wavy white streaks it leaves on your shoes and the stinging in your dog’s paws).

What’s more, the constant leaching of salt from contaminated soil into the city’s streams and rivers means that Toronto’s waterways are chronically salinated, well beyond normal levels, even in the summer.

“In highly urbanized area, most of the fish and bugs, if they were sensitive to chloride, they’ve either left or died already,” says Wallace, whose work focuses on watershed monitoring and reporting. She likens aquatic species’ aversion to salty water to humans’ intolerance of the atmosphere of outer space. “Once road salt starts going into the stream, it changes the atmosphere they’re living in. It’s also very dehydrating,” Wallace explains.

What’s left are hardy organisms that can tolerate urbanized watersheds and their high levels of salt. One sensitive fish of particular concern is the Redside Dace. The minnow is native to North America and, in Canada, it’s only found in Ontario. With more and more urbanization in the province coupled with persistent overuse of road salt, the fish is teetering on extinction.

It’s not just the watersheds that are affected by corrosive compound. In 2001, Environment Canada released a detailed five-year study on the environmental impact of road salt. They concluded that, at the current levels being used, salt was harmful to freshwater ecosystems, as well as soil, vegetation, drinking water, and wildlife in general. Road salt was designated as a toxic substance. “Usually when you declare a substance as toxic, regulations follow,” says Tim Van Seters, manager of the Sustainable Technologies Evaluation Program at TRCA. But that’s not quite what happened. Instead, a multi stakeholder committee created a voluntary code of practice—recommendations, if you will—for the environmental management of salt.

Since then, many large municipalities across Canada, including Toronto, have developed road management plans. They’ve started measuring the temperature of the roads before salt applications, so they know how much to use and when. They track where they salt using GPS. They rely more on road weather information systems so they can put salt down before the storm starts, and sometimes pre-wet the salt so it sticks to the road more effectively, allowing them to cut down on how much they use.

While all of this is important for minimizing use, a major barrier remains: the best practices recommendations don’t extend to private property-owners, who are responsible for 40 per cent of the road salt used in Toronto.

“There’s a fear of liability,” says Van Seters. “Fear that someone might sue a property owner as a result of slips and falls. That pushes up the rates of salt they put down.” Those rates, according to the TRCA, are up to 13 times greater than what’s applied to roads.

Wallace knows all too well that using salt is critical for public safety. “There’s no way around it,” she says. “But we could be using it much more efficiently.”

That’s exactly what Van Seters is aiming to do with the Salt Application Verified Equipment Program. The initiative helps give private contractors the tools and knowledge to follow the same best practices the municipalities use: to lower their rates, update their equipment and, most importantly, make sure their machinery is properly calibrated. “You can’t follow recommended rates when you don’t know how much is coming out of your spreader,” says Van Seters. It’s a simple fix that can have enormous impacts on how much salt the city absorbs. In fact, using calibrated salt spreaders that adjust the amount of salt applied according to the truck speed, can reduce the amount of product that’s used by as much as 47 per cent, compared to widely used manual spreaders.

Van Seters has teamed up with two other nearby conservation authorities, Lake Simcoe and Credit Valley, to launch SAVE pilot programs. The group is also working to merge SAVE with the successful Smart about Salt certification program, which offers salt management training for property owners and contractors across Ontario. The goal, eventually, is to create one certification program for private contractors and facility managers that the province will recognize as meeting the best practices guidelines.

A handful of municipalities across Canada, including Niagara, have experimented with alternatives to road salt. A mixture of saline, sugar, and beet juice is one popular way to cut down on the stuff, but it’s not a perfect solution. Namely, it’s a pricey alternative and it still contains salt.

Both Van Seters and Wallace agree that doing away with salt isn’t an option—certainly not any time soon. But simply enforcing best management practice, for municipalities and private property owners alike, can help significantly limit the toxic, yet necessary, substance from seeping into our environment.