North American Waterways are Becoming Saltier and More Alkaline

College of Computer, Mathematical, and Natural Sciences

New UMD-led research highlights the need for better regulation of road salt, fertilizers and other salty compoundsAcross North America, streams and rivers are becoming saltier, thanks to road deicers, fertilizers and other salty compounds that humans indirectly release into waterways. At the same time, freshwater supplies are becoming more alkaline.
Salty, alkaline freshwater can create big problems for drinking water supplies, urban infrastructure and natural ecosystems. For example, when Flint, Michigan, switched its primary water source to the Flint River in 2014, the river’s high salt load combined with chemical treatments to make the water more corrosive, causing lead to leach from water pipes and creating that city’s well-documented water crisis.
A new study led by University of Maryland researchers is the first to assess long-term changes in freshwater salinity and pH at the continental scale. Drawn from data recorded at 232 U.S. Geological Survey monitoring sites across the country over the past 50 years, the analysis shows significant increases in both salinization and alkalinization. The study results also suggest a close link between the two properties, with different salt compounds combining to do more damage than any one salt on its own.
The analysis, which has implications for freshwater management and salt regulation strategies in the United States, Canada and beyond, was published in the January 8, 2018 Early Edition of the Proceedings of the National Academy of Sciences. Researchers at the Cary Institute of Ecosystem Studies, the University of Connecticut, the University of Virginia and Chatham University co-authored the study.
“We created the name ‘Freshwater Salinization Syndrome’ because we realized it’s a suite of effects on water quality, with many different salt ions linked together. We didn’t know that before,” said Sujay Kaushal, a professor of geology at UMD and lead author of the study. “Many people assume that when you apply salt to the landscape it just …

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