Road Salt Runoff and our Nation’s Waters

As we all know, the winters here in Canada can be harsh, especially when it comes to driving. One of our most commonly used methods of protection may certainly be keeping our roads less icy, but could be having a detrimental effect on our water. Road salt has been recognized as a threat to aquatic life for years, but do we really know how threatening?

In Canada this could be a big problem. With our hectic winters, icy roads are a guarantee. But is using extreme amounts of salt on our roads really worth the risk?
It is shown that over the last seven decades road salt use has been steadily increasing and has no indication of slowing. With increased urban development more winter-proofing operations are being performed. In the U.S in the past 10 years, over 16 million metric tons of road salt have been sold per year. With this constant increase it comes to our attention the harmful effect it could have on our receiving waters.

A study has been performed to test the effect of runoff from road salt on aquatic life. Local, and regional waters were tested in Milwaukee and Wisconsin. In Milwaukee, twelve streams were tested for water chemistry as well as aquatic toxicity. These streams had urban land-use and were tested in comparison to a stream of natural areas and no land use. Eleven Wisconsin streams were tested on a Regional scale for elevated specific conductance and these results were compared to a national scale historical study. The waters were all tested during periods of road salt application. Nearly all samples were within 10% of a linear regression result.
The results showed that toxicity was found in 7 of 12 Milwaukee streams. High levels of specific conductance were observed at all sited of the eleven Wisconsin streams. Nationally, historical data shows that chloride concentrations exceed the water quality criteria of the US Environmental Protection Agency.

These results no doubt show how negative an effect road salt runoff is creating. So as we drive along our icy roads this coming winter, perhaps we should keep in mind the environmental effect it is having on our water. The ice will always be there, so perhaps it’s time we found an alternative to salting our roads.
Sarah Mark


Cited Works:
http://pubs.acs.org/doi/full/10.1021/es101333u?prevSearch=&searchHistoryKey=
Corsi, S.R., Graczyk, D.J., Geis, S.W., Booth, N.L. and Richards, K.D. 2010. A fresh look at road salt: aquatic toxicity and water quality impacts on local, regional, and national scales. Environ. Sci. Technol. 44(19) 7376-7382.