As the use of de-icing salts has tripled over the past 45 years, salt concentrations increase dramatically in streams, rivers, lakes and other freshwater sources.

Overuse of road salts to melt snow and ice threatens human health and the environment when they enter drinking water sources, and new research from the University of Toledo highlights the need urgently for policy makers and environmental managers to adopt a variety of solutions.

The study entitled “Road Salts, Human Safety and the Rising Salinity of Our Fresh Waters” is published in the journal Frontiers in Ecology and the Environment and presents how road salts harm the ecology, contaminate the drinking water supply and mobilize harmful chemicals, such as radon, mercury and lead, then outlines suggested best management practices.

“The magnitude of the road salt contamination problem is significant and requires immediate attention,” said Bill Hintz, assistant professor of ecology at Toledo and senior author of the research based at UT’s Lake Erie Center. “Since road de-icers reduce car crashes by over 78%, we have strived to strike the right balance between human safety and mitigating the negative environmental and health impacts caused by the spill. of salt in our streets and highways to ensure the safety of people and traffic. “

In a major example, researchers claim that the overuse of road salt likely contributed to higher levels of corrosive chloride in the water supply in Flint, Michigan, in 2014, leading to the release of lead from distribution lines. of water.

Another example shows that high concentrations of de-icing salt generally occur in private wells located near low-elevation roads or downstream of highways.

The most common de-icers are the inorganic salts of sodium chloride, calcium chloride, and magnesium chloride, all of which are used in both solid and liquid or brine form.

The study examines how the current federal safe limits for salt concentrations established by the United States Environmental Protection Agency in 1988 to protect fish, plants, and other aquatic life in ecosystems from fresh water are generally outdated.

The number of salinized rivers is particularly alarming. Research highlights recent studies that show urban waterways with salt concentrations more than 20 to 30 times above the EPA’s chronic chloride threshold of 230 milligrams per liter.

“The current EPA thresholds are clearly not sufficient,” Hintz said. “The impacts of de-icing salts can be sublethal or fatal at current thresholds and recent research suggests that negative effects may occur at levels well below these thresholds. “

Research suggests several solutions, including:

Appropriate storage facilities – covered structures with a concrete base

Anti-icing, the application of liquids such as brines to road surfaces prior to winter storms, which prevents ice from bonding to surfaces and facilitates removal operations

Sharp-edged snow plows made up of several smaller, spring-loaded snow plows, which adapt better to road surfaces compared to conventional snow plows with a single fixed edge, to increase the efficiency of snow removal. snow and ice and reduce the need for de-icing salt

Post-storm performance assessments to determine if the treatment used was appropriate for the weather system and if it should be changed in the future.

“Given the lack of environmentally friendly and cost-effective alternatives, the large-scale adoption of best management practices is necessary to curb the increasing salinization of freshwater ecosystems resulting from the use of de-icing salts,” said Hintz .

Hintz collaborated with scientists from Montana State University and the Rensselaer Polytechnic Institute on the study.