Road salt hurts the Great Lakes

Photo: Ruby Pajares

Road salt is a staple of Canadian winters. When temperatures dip below 0°C road salt is an effective solution for icy conditions.

By the end of last year’s epic winter, the City of Toronto used 210,000 tonnes of road salt – approximately 80,000 tonnes more than average.

But what happens when road salt washes away?

Road salt is mostly made up of chloride. Because chloride is water-soluble, melting snow carries road salt into waterways and chloride levels spike.

Large concentrations of chloride pose risks to plants, wildlife, and the aquatic environment. High levels of salted water can "knock-out" fish, causing fish kills.

In January 2011, the TRCA sampled Toronto’s Mimico Creek following a storm. Their findings revealed a chloride concentration of 18,200 milligrams per litre (mg/l), just shy of seawater levels (19,250 mg/l).

There are also concerns for drinking water. The TRCA have found lingering traces of chloride in groundwater, the soil, and high levels in the summer when salt is not being used.

Currently, municipalities are experimenting with various road salt alternatives.

Choosing road salt

Road salt mainly consists of sodium chloride, calcium chloride, magnesium chloride, potassium chloride, and urea. There are pros and cons to each.

Generally, consider road salts made of magnesium chloride and potassium chloride as they tend to be less aggressive. For extra reading, this chart provides a detailed product comparison.

Hope this helps. Drive safely!