For 80 years, Madison’s lakes have gotten saltier, according to Hilary Dugan, an associate professor and researcher at University of Wisconsin-Madison’s Center for Limnology.
The salinity of Madison’s lakes was close to zero a century ago and road salting has been the biggest source of contamination, she said. Researchers like Dugan closely monitor chloride levels in local waterways because it’s easier to track the environmental impacts than sodium.