How Road Salt Protects Drivers Yet Poses Environmental Risks: Insights from Researchers | CBC News

After it snows, putting salt on roads and sidewalks makes it safer for drivers and walkers. However, researchers in London, Ontario warn that this can harm local rivers and wildlife.

Those studying salt pollution are urging cities and residents to think about how much salt they use during the winter. Taryn Smit, an ecologist with the Canadian Conservation Corps, emphasizes that while salt is necessary for safety, we can reduce how much we apply. “We can still be safe without using so much salt,” she explains.

The salt on our roads is similar to table salt—sodium chloride. This salt lowers water’s freezing point, which helps prevent ice from forming and melts existing ice.

However, when snow melts, the salty water flows into streams and rivers. This can disturb aquatic life. Smit points out that too much salt can make it hard for fish and frogs to balance salt and water in their bodies. “It’s like not drinking enough water,” Smit says. “It leads to dehydration and can make them sick or even kill them.” This imbalance can trigger a chain reaction within the ecosystem.

Surprisingly, salt pollution doesn’t just affect fish. Even deer are drawn to salt on roads, increasing their chances of being hit by cars.

In the Upper Thames River, salt levels in rural areas are generally acceptable, but urban spots are closer to exceeding safety guidelines. Residents and city officials should work on reducing their salt usage. Smit suggests shoveling snow and clearing ice before applying just one tablespoon of salt per square meter. After the snow stops, there’s another helpful tip.

“Once the salt has melted the ice and it’s no longer needed, sweep it up and save it for next time,” Smit suggests. This not only cuts down on the amount of salt used but also saves money.

Researchers at Western University are also studying road salt, particularly its impact on metals and concrete. Robert Addai, a PhD candidate, is examining how different salts corrode materials and their environmental effects. “We’re looking at how effective the salt is for melting ice and the costs involved,” he notes.

Addai warns that using cheaper salt today might lead to higher repair costs in the future due to corrosion. His research has explored nine types of salt to find the most eco-friendly options. All salts corrode, but sodium chloride mainly harms metal. Mixed salts can exacerbate damage since they affect both metal and concrete.

“Organic salts can damage concrete more than metals, and repairing concrete can be pricier,” he explains. Sticking with simple salts like sodium chloride and calcium can be a more sustainable choice.