The unseen costs of salting Toronto’s streets
By Melissa Wilson
January 30, 2012
Every day Amy Powell leaves her Leslieville home to walk her two hound dogs. Her route takes her along Queen Street East, to the bridge at the Don River, down the stairs to the bike path and then south until she ends up at Cherry and Lakeshore. The walk can be a chore in poor weather, but for Powell, more cumbersome than a few inches of snow is the few inches of salt she often sees scattered along the route.
“Anytime there’s a little bit of snow, there are two inches of salt,” she says. Besides frustrating her with an excess of sodium chloride (road salt is more or less the same as regular table salt), the salt stings her dogs’ feet, so she has to buy expensive booties to protect them. “It gets to the point where you have to put the boots on them or you can’t even walk outside.”
At the street level, the city is filled with dog owners like Powell who are frustrated with the effect road salt has on their daily routines — be it pups’ sore paws or the chalky stains left on jeans and boots — but on a larger scale, Toronto’s use of road salt is doing more permanent damage. Road salt can corrode concrete, steel and asphalt, meaning the city’s infrastructure (roads, parking garages, and even TTC vehicles) need to be replaced or repaired more often. From an environmental standpoint, salt can run from the streets and sidewalks into the sewers, eventually making its way into nearby rivers and lakes where the chloride severely disrupts the ecosystem.
According to Kevin Mercer, managing director of Riversides, a non-profit organization committed to promoting water quality, the Don River should have a natural chloride level of 50 milligrams per litre. Instead, it regularly has a chloride level of 300 milligrams per litre, except in the winter after a snowfall (and a good salting), where the water in the river becomes so salinated that you get a chloride level of between 1500 and 2000 milligrams per litre.
“The Don, Humber and Black Creek rivers are the most heavily salt-infused rivers in Canada,” says Mercer.
The City of Toronto is well aware of the problem, however it’s engaged in a precarious balancing act regarding public safety. “We’re very concerned about the environmental impacts of salt use,” says Peter Noehammer, director of transportation services for the City of Toronto, “But our mandate is to provide safe roads and sidewalks according to provincial regulations. We have to respond to snowy or icy conditions quickly, and salt is still the most effective deicing chemical available to us.”
Noehammer says the City has explored many alternatives to traditional road salt. There are other options available that are more potent, he says, thus the City wouldn’t have to use as much, but they are still chloride-based, and cost much more. As it is, the City spends between $10 and $12 million each year on 125,000 tonnes of road salt.
The City sometimes puts down liquid salt brine when it knows a snowstorm is coming, so that it can minimize required salt use.
Another alternative the City has been trying out recently is a non-chloride liquid derived from sugar beets (essentially, it’s beet juice) that has some deicing properties, and works in temperatures as cold as -29 C, whereas salt becomes ineffective at -20 C. The City uses the beet juice on really cold days, but it’s too expensive to use all the time. It’s about twice as expensive as regular brine, and still must be used in combination with road salt, not as a replacement.
Potassium acetate is another alternative to road salt, and it’s not chloride-based, but it costs literally 10 times as much. “So instead of $10 million a year, it’d be $100 million. It’s just not practical for a municipality,” says Noehammer. “We can’t just spend whatever we want. We have to be accountable.”
The City has decreased its salt use already, down from the $140,000 tonnes that were being used ten years ago, and Noehammer says reducing salt use remains the his top priority — after public safety.
Noehammer isn’t thrilled about the continued salt use, but it’s a catch-22, because as citizens remain safe on sidewalks and roads, Toronto’s infrastructure and surrounding ecosystems are slowly eroding.
“What road salt represents ecologically speaking is a chronic, as opposed to catastrophic, disaster,” says Mercer. “But it’s a disaster, nonetheless.”