GardenDrumDe-icing road salt causes environmental damage

Salt truck Milwaukee Photo Michael Pereckas

Salt truck Milwaukee Photo Michael Pereckas

Smithsonian.com has reported on the environmentally damaging effects of de-icing road salt, a timely discussion given USA’s recent deep freeze. A staggering 40% of the country’s streams have chloride levels that are higher than what’s safe for aquatic life.

With more and more roads pushing into new areas, the demand for a safe driving surface in snowy+icy conditions mean that ever more salt is being spread – and then washing off into the surrounding environment. As the salt dissolves, it breaks down into its separate components of sodium and chloride. Sodium doesn’t wash a long way from its source but chloride is much more mobile and can contaminate streams and wells many miles away.

Several studies have found that the levels of road salt that end up in nearby streams can have adverse consequences for aquatic and semi-aquatic plants, as well as amphibians, like frogs and salamanders, and fresh-water crustaceans. A study in Massachusetts also found that higher salt levels can contribute to the spread of invasive, more salt-tolerant plants. High salt levels near roadsides also damage soil structure.

Road maintenance authorities are trying out news ways of using salt to lessen how much of it is used, such as spreading it before storm events rather than after, and mixing it with sand and gravel. There are also experiments with other de-icing materials, including cheese brine, molasses and beet juice.

In Canada, salt is now classified as an environmental toxin and there are new stricter, guidelines for how it can be used.

Read more at Smithsonian.com

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