Road safety could have serious environmental impacts


This winter has been tough so far. Not only with frigid temperatures, but also a record-breaking amount of snow in January alone in the Ottawa area. This has meant A LOT of snow days for the kids and many “work from home” days for people who commute into the city.

There is no doubt about it, we rely heavily on the people who look after the roads to allow us to get from point A to point B over the winter months. Municipal and County Public Works departments have been working tirelessly this winter to make driving around the municipality as safe as possible.

So how to they do it? Other than snow removal, both the Municipality of North Grenville and the United Counties of Leeds and Grenville use surface treatments to make the roads safe. Both sand and salt are used to help melt the snow and ice and provide more traction for vehicles travelling on the roads. The ratio of sand to salt used depends largely on the class of the road and how long the municipality or county has before provincial regulations expect them to return the road to “bare pavement” status.

Director of Public Works for the United Counties of Leeds and Grenville, Arup Mukherjee, says the County uses mostly salt to melt the ice and snow and get the main thoroughfares for which they are responsible back to bare pavement as soon as possible. “Salt is better at melting the snow and ice,” he says. “The sooner the road gets to bare pavement the better.”

Although this is very beneficial for the safety of those who depend on the roads, salt spreading in the winter has been proven to have some serious environmental impacts. Many people don’t think about it, but when the snow or ice on the roads and sidewalks melt, the salt (or sodium chloride) goes with it, seeping into the ground water or running into streams or rivers close by. The World Wildlife Fund (WWF) Canada’s watershed reports showed very high threats from pollution in the Great Lakes watershed. “In this region, with its dense network of pavement and people, excessive use of salt in the winter is responsible for the toxic conditions damaging aquatic life,” says a WWF blog post from January 2018.

Patty Gillis, a biologist with Environment and Climate Change Canada, has studied the effect of road salt on the at-risk species of fresh water mussels. Through her research, she has concluded that road salt definitely has an effect on mussel populations, especially in the early stages of life. Mussel populations are often used to assess the health of a body of water. If mussels are dying, it is most likely that other life forms are too.

According to Patty, the warming and cooling that happens over the winter causes pulses of sodium chloride to run into the rivers, lakes and streams, shocking many of the species that live there many times over. “We don’t know the long-term impact of being hit over and over,” she says. These pulses don’t just happen over the winter. Road salt that seeps into the groundwater is known to bubble up over the warmer months and flow into rivers, streams and ponds, so animals that live there do not get a break from the shocks of sodium chloride.

According the WWF Canada, road salt is not just a concern for aquatic animals, but for humans as well. Road salt can also end up in our drinking water, especially for people who rely on dug wells. Health Canada sets parameters for how much salt can safely be in our drinking water; however, in some areas, like the Waterloo region, it is not uncommon for salt to reach the concentration where the water coming out of the tap tastes salty.

Patty says that because of all the research that has been done highlighting the detrimental effects of road salt, there have been regulations put into place to lessen its impact on the environment. Counties and municipalities that use road salt must have a salt management plan that outlines the practices they use to limit the amount of salt used, while still keeping the roads safe. Arup says the County has specific practices they use to store, measure and spread the salt in a responsible way. They also know when and where to use the salt to make sure they use the least amount of salt to be effective. For example, salt does not melt snow or ice if the temperature is below -12; therefore, they use a mix that is primarily sand during particularly cold days to provide traction on the road, without the expectation of melting the snow and ice.

Karen Dunlop, the Director of Public Works for North Grenville, says the municipality uses a 6 to 1 sand/salt mix to spread on the roads they maintain. “It’s cheaper and more environmentally friendly, but also provides traction and holds salt better,” she says. “We find that a higher sand to salt ratio works for our equipment deployment method.”

Although there are regulations in place that help to mitigate the impact of road salt on wildlife and drinking water, Patty says there needs to be more education for private landowners who often use much more salt than is needed on walking paths and parking lots. “In 2001, the Canadian Environmental Protection Act declared road salt a toxic substance,” she says. “But they can’t ban it, because it is there to keep people safe.” Not-for profit organization, The Smart About Salt Council, is trying to combat this by creating a training program for residents, property owners, and snow and ice removal contractors to educate them on how to use salt responsibly. “We all have a role to play in reducing the amount of salt we use,” it says on their website. “Our members are committed to maintaining safe winter conditions with less salt-related damage.”

Patty says that, at this point, the level of salt in the water doesn’t often rise to dangerous levels. However, if the spreading of road salt is not controlled and minimized, it will pose a serious threat to the environment in the future. “The public is expecting bare pavement, but they don’t think about the mussel at the bottom of the pond,” she says. “Maybe, once the fish start dying because there is nothing to eat, they will take notice.”


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