Champaign, Ill. - Salt crystals on roads and parking lots shimmer in the muted sunlight of an Illinois winter day. Once washed away into rivers and streams, salt contaminates the local environment, according to groundwater geochemist Walt Kelly with the University of Illinois’ Prairie Research Institute (PRI).

Sodium chloride, or road salt, is water soluble, so it dissolves and flushes away into surface water, sometimes in concentrations that exceed the U.S. Environmental Protection Agency’s standard, particularly in highly populated areas. High salt concentrations are often found in rivers and streams after a significant amount of snow has melted.

In northeastern Illinois, researchers also have found increased salt concentrations in groundwater, said Kelly, a scientist at the Illinois State Water Survey, a division of PRI. Groundwater moves slowly and provides a year-round source of water to rivers. Even in the summer and fall, rivers can contain a high salt content from previous winters’ ice and snow removal.

Sodium chloride is unhealthy for fish and plants in aquatic areas such as wetlands and roadside ditches. Plants that are intolerant to salt give way to invasive species, including cattails and Phragmites, which are large perennial grasses. Salt also has an adverse effect on trees and in soils.

“Many have studied this problem,” Kelly said. “But salt on the roadways is cheap, effective, and easy to apply.”

One way to reduce the amount of salt in the local environment is to modify how salt is applied. Some operators spray brine on roadways when a snow or ice storm is predicted. This option is even more effective than salt application, melting snow quickly as it lands on road surfaces.

The downside: if the snow doesn’t materialize, the brine will stick to roads for several days, then merely wash away.

Operator training helps to cut the amount of road salt that is distributed, and some Illinois counties and municipalities provide certificates for operators who train to use less salt, particularly in vulnerable areas, including parks and nature preserves.

“There are things that people can do to mitigate environmental problems associated with road salt application,” Kelly said. “If there are no low-cost alternatives though, people won’t change their methods. This is the price we pay.”

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Source: Walt Kelly - (217) 333-3729, wkelly@illinois.edu

Editor: Lisa Sheppard (217) 244-7270, sheppard@illinois.edu