This winter's heavy snowfall is responsible for record amounts of salt on Wisconsin roads, but water quality experts are raising concerns about the effects of so much salt on the environment.

In metropolitan Milwaukee, road salt, or sodium chloride, and other melting agents wash into urban streams at levels that potentially kill fish and other aquatic life until it passes.

Last year, a scientist with the U.S. Geological Survey found that water quality at seven of 12 streams in metropolitan Milwaukee showed signs of acute toxicity on fathead minnows and a type of water flea after two storms on Feb. 26 and March 7. Scientist Steve Corsi said the findings of chloride concentrations exceeded the EPA's toxic standard of 850 parts per million on the Kinnickinnic, Menomonee and Root rivers and on Honey, Underwood, Lincoln and Little Menomonee creeks.

On Feb. 26, 2007, at Honey Creek in Wauwatosa, chloride levels essentially became saline water for a few hours, hitting 6,470 parts per million.

By contrast, Corsi used Parnell Creek in the Kettle Moraine State Forest as a control stream. It was not affected by road salt and registered 20.4 parts per million, he found.