Freshwater lakes are getting saltier

Apr 25, 2017

North America's freshwater lakes are getting saltier due to increased development and exposure to road salt, according to a study that included contributions from Michigan State University.

The study shows that several Midwestern and Northeastern lakes are facing increasing chloride trends and long-term salinization.

“There’s a careful balance between protecting public safety on icy roads and ensuring that lake ecosystems, and all the important services they provide, are safeguarded long term.” Nicholas Skaff, an MSU doctoral student in the Department of Fisheries and Wildlife, told MSU Today.

Nearly 23 million metric tons of sodium chloride-based deicer is used on our roads per year. Eventually, the road salts wash into nearby water bodies, where they become a primary source of chloride pollution.

Elevated chloride levels have been proven to alter the composition of the aquatic ecosystem. Certain circumstances show that salinization can prevent lakes from mixing, which lowers the oxygen levels, kills aquatic life and reduces water quality.

The study's authors advocate extending shoreline management practices to go further than lake perimeters. Zoning regulations are usually only enforced within 300 meters of a lake and many of these lakes lack monitoring programs that adequately track their health.

If salinization trends continue at their current rate, many North American lakes will surpass the EPA’s recommended chloride levels within the next 50 years.