While road salt is highly effective at de-icing surfaces and very necessary during harsh winters, it places a heavy burden on freshwater ecosystems.
Several studies -dating back to the 1970s- have shown that road de-icing salt has a negative impact on soil, vegetation, wildlife, surface water, groundwater and human health. “We have an unhealthy addiction to road salt,” said Claire Oswald, a hydrologist and associate professor at Ryerson University in Toronto, Ontario.
In the late 1990s, the Canadian government started to look at road salt usage and best management plans. The Canadian Water Quality Guidelines include the maximum thresholds for when chloride becomes harmful to amphibians, algae, aquatic plants, aquatic insects, fish and invertebrates like mussels, she said.
Danelle Haake, stream ecologist and director of Illinois RiverWatch: “If you ask someone in the grocery store about road salt, they probably have no idea of the negative environmental consequences.”
Seeking safe alternatives
Synthetic de-icers are typically expensive which has limited their widespread use. Researchers also caution against trading salt for an artificial product.
Oswald said all types of agricultural alternatives have been tested so far including cheese brine, pickle juice and the runoff from brewing beer. Beet juice from sugar beet processing has emerged with the best potential as an alternative to sodium chloride, she said.
According to michiganradio.org, Haake said using beet juice as a road de-icing agent means trading sugar for salt. While sugar may be less toxic to aquatic life, she said high sugar levels lead to other problems. Bacteria use sugar as a food source and strip oxygen from the water. High bacteria levels can lead to a process called deoxygenation, which is lethal to fish and other aquatic life.