Article by CVC’s Adam Wilford.
Photo by MountainEagleCrafter via Flickr Creative Commons.
Road salt saves lives and prevents injuries. After harsh winter storms we use it on our roadways, walkways, and driveways to melt away slippery surfaces. Without it we would see more pedestrian slips and car accidents.
As great as road salt is at keeping us safe, it also has negative effects. Road salt has been designated as a toxic substance under the Canadian Environment Protection Act because of its damaging effects on plants and animals. If environmental concerns aren’t enough, road salt can also contaminate our local drinking water, damage structures such as bridges and cause our cars to rust.
Road salt is usually made up of sodium chloride, but occasionally is made up of chloride and another element. For the purposes of environmental monitoring, we measure road salt in our waterways in mg of chloride per litre of water. CVC monitors chloride concentrations at several locations in the Credit River watershed.
According to RiverSides, an untouched natural waterway in Ontario would have chloride levels ranging from 1-30 mg/L. The Canadian Council of Ministers of the Environment (CCME) has set a short-term chloride concentration guideline of 640 mg/L and a long-term guideline of 120 mg/L. The short-term guideline protects most species during a brief period of high chloride concentrations, while the long-term guideline protects river or lake ecosystems over long periods of chloride exposure. Concentrations exceeding these levels have damaging effects on wildlife and ecosystems as a whole.
In certain sections of the Credit Valley watershed, chloride concentrations can be found well above 1000 mg/L. This is much higher than the established guidelines and likely has serious effects on environmental health.
Fortunately, there are new technologies that help lower salt use on our roadways. Many municipalities, such as the Region of Peel, now apply anti-icing agents to the road before winter storms and use pre-wetted salt. These techniques reduce the overall amount of salt needed and are more effective than simple rock salt.
You can make a difference at home by applying salt sparingly (but use enough to melt away slipping hazards), using salt only when and where necessary, and by using road-salt alternatives. A great resource for homeowners, contract and commercial operators is the Smart About Salt Program.
There are many alternative de-icing products available. However, some products can have other environmental impacts. It’s important to read the label and do your research before buying.
Road salt is only part of the solution. For your own safety please remember to wear sturdy winter footwear designed to grip and to use snow tires on your car for better traction. If we work together we can reduce our use of road salt and return our local waterways to healthy chloride levels.