Road Salt Contaminating Fresh Water Lakes Around North America

A study published in Proceedings of the Natural Academy of the Sciences found that in the 371 lakes observed, 44% showed evidence of long-term salinization. "No federal body tracks how much salt gets spread on our roadways or makes its way into our lakes. So the researchers hoovered up a vast number of different data sets, produced by states, municipalities and universities," Ben Guarino reports in the Washington Post. The study has big implications for drinking water around the country. "Extrapolating that finding for all of North America, at least 7,770 lakes are at risk of elevated salt levels — a likely underestimate," Guarino reports. This salt is coming, in large part, off roads and highways.

These salts cannot all be filtered out of drinking water. "Increased salt in drinking water poses health problems to humans who have kidney trouble, use dialysis or have hypertension," Guarino writes. And while some suggest that better management of salt use could curb the issue, there's evidence that salt consumption may continue to rise. "In winter 2014, the Wall Street Journal reported that road salt prices surged by 20 percent due to a huge demand," Guarino writes.

This exposes another challenge to the preservation of lakes in North America, which lost some of their protections following legislation from a Republican Congress, signed by President Trump, repealing Surface Mining's Stream Protection Rule.