Salt is the cheapest and most commonly used de-icing agent for roads in Canada, but it turns out this inexpensive option has a high environmental cost. Research has found that salt harms wildlife, rivers, lakes, and even cars and roads.
Canadians use tonnes (actually, millions of tonnes — up to seven million per year, according to a 2009 survey) of salt each year to help clear icy roads, but now, some municipalities are changing their policies as a result of studies showing that it harms the environment and may cost more money than it saves. According to some calculations, the damage from salt adds up to almost five billion dollars per year.
There are several reasons road salt is harmful. Sodium chloride (i.e., most road salt) dissolves easily and makes its way into waterways, where it can create toxic conditions for wildlife that lives there, affecting fish, frogs, and turtles, who can be killed by high salt levels. Salt is also highly corrosive — and it doesn’t just eat away at river and lake beds. It also damages cars, roads, pipes, and other infrastructure. Further, the presence of salt can also lure wildlife toward roads (like humans, lots of animals love salt), which may increase the number of wildlife-related accidents.
Fortunately, there are alternatives to using salt, and some cities are already switching over. Calgary is expanding the use of beet juice, which is less corrosive than salt, and some municipalities in Quebec are turning to wood chips as well.
Eric Westram, the mayor of Rosemere, Quebec, says that he thinks wood chips are a viable alternative. “We used it [Tuesday] on a street where the slope is really steep and it’s like there was no ice,” he told CTV News.
He also pointed out that Switzerland has been using wood chips instead of salt on roads in the Alps since 2008, and “there’s no contest.” Wood chips are effective in temperatures as low as –30ºC, Westram said, whereas salt is only good down to about –15.
Other alternatives to salt that have been used include potato juice, cheese brine, and pickle brine, which are are byproducts of food production.
While some cities are trying to reduce their use of salt by mixing it with alternatives, there is still plenty of salt going onto Canadian roads. The World Wildlife Fund is currently calling for policy change and an Ontario-wide strategy for salt reduction.
As for Westram, he’s currently testing the limits of wood chips in Rosemere. “We’ve been using it for three weeks on two streets near a river where there’s a lot of dampness and a lot of ice formation,” he said. “I think we found something that has a future.”