In some Wisconsin rivers levels of chloride concentrations exceed by 10 to 15 times the levels set by the U.S. Environmental Protection Agency (US EPA) to protect aquatic life such as fish, amphibians, and crustaceans, according to a recent story in EcoNews and based upon a study by the United States Geological Survey (USGS) study (click here to read the USGS study)
Among the affected rivers in Wisconsin are the Menomonee, Kinnickinnic, and the Rock River at Afton, WI. The high levels of chlorides persist from winter into summer, when they decline somewhat.
“It’s likely that many of the organisms in rivers that are sensitive to chloride are simply no longer there,” said Steve Corsi, a research hydrologist with the U.S. Geological Survey (USGS) who was quoted in the EcoNews story.
Impacts Are Not Confined to Surface Waters
Excessive chloride levels, which have risen for years, affect groundwater, drinking water supplies, soil, vegetation, and wildlife according to findings from Environment Canada and presented in a 2012 report entitled “Sources of Chloride to Lake Wingra” by Roger Bannerman, an environmental specialist with the State of Wisconsin.
The Bannerman report is an excellent primer on the topic of why it is important to reduce road salt usage in the Lake Wingra Watershed. Bannerman explains how road salt travels from roads into waterways, regulatory standards and guidance for chloride use, and examples of a range of impacts from excessive chloride use.
The range of consequences of high chloride concentrations not just on surface and groundwater but also on wetlands, and uplands means that the issue is a public health and environmental concern for the entire watershed.
Lake Wingra is Highly Salted
In 2012 Lake Wingra ranked Number 1 in chloride concentrations with 112 ppm/chloride, ahead of Lake Monona (66.1 ppm/chloride) and Lake Mendota (47 ppm/chloride), according to a report prepared by the Department of Public Health for Madison and Dane County. The high concentration in Lake Wingra is due in part to its relatively small area compared to the other two larger lakes. The 2012 report is summarized in a story by Madison Commons (read it here). This blog reported on the chloride issue in this post from earlier this year.
Overuse of Road Salt is Commonplace
It is not just the municipalities that are responsible for spreading–and excessive use–of road salt and other ice melting chemicals–businesses, apartment units, shopping centers, and residents all play a role. The Cut Salt blog by David Thompson has documented gross overuse of road salt and icemelters over the past few years.