Human activities are exposing US rivers and streams to a cocktail of salts, with consequences for infrastructure and drinking water supplies. So reports a new study in the Proceedings of the National Academy of Sciences that is the first to assess the combined, long-term changes in freshwater salinity and alkalization across the country.
Human activities are exposing US rivers and streams to a cocktail of salts, with consequences for infrastructure and drinking water supplies. So reports a new study in the Proceedings of the National Academy of Sciences that is the first to assess the combined, long-term changes in freshwater salinity and alkalization across the country.
Using five decades of streamwater data from 232 U.S. Geological Survey monitoring sites, researchers found 37 percent of the drainage area of the contiguous US experienced a significant increase in salinity, with a concurrent increase in alkalization of 90 percent.
Salt ions, damaging in their own right, are driving up the pH of freshwater, making it more alkaline. Both of these variables shape water quality and can influence the stability of pipes and other water delivery infrastructure. For example, when Flint, Michigan switched its primary water source to the Flint River in 2014, the river's high salt load caused lead to leach from water pipes, creating that city's well-documented water crisis.
Co-author Gene E. Likens, president emeritus of the Cary Institute of Ecosystem Studies and a Distinguished Research Professor at the University of Connecticut, Storrs explains, "Long-term monitoring is vital to understanding the pressures facing our nation's freshwaters from increased salt loading, and for guiding strategies that protect drinking water. Road salt, irrigation runoff, and sewage are obvious culprits. But so is acid rain, which can release alkaline salts that compromise the chemical integrity of freshwaters."
Read more at Cary Institute of Ecosystem Studies
Image: Road salt pile in Boston, MA. Throughout the Northeast, road salt is used to deice winter roads. (Credit: Allison Cekala)
