Freshwater streams and rivers are getting saltier and more alkaline

Five-stage scoring scale gauges the harmful effects of road salt on freshwater.

Road salt affects water quality and harms freshwater bodies.

A new study led by the US National Science Foundation (NSF) grantee researchers at the University of Maryland revealed how salinisation from road salt combined with other pollutants can impact the ecological balance of freshwater bodies, and can potentially create conditions that harm aquatic life and pollute drinking water.

Sujay Kaushal, lead author of the study, explained: “This is a problem that’s caused by road salt, but also other sources of salt pollution in our environment – the fertilisers we put on crops, the sewerage we put out, the roads that break down. It’s not just sodium chloride that’s increasing, it’s all these salt ions that are dissolved in water that contribute to salt pollution.”

IN addition to coining the term “Freshwater Salinisation Syndrome”, the team created a five-stage scale to assess salt pollution damage and a salinisation scorecard to evaluate water quality and salinisation risk. The study, published in Limnology and Oceanography Letters, offers an understanding of the effect road salt has on waterway ecology and details risk factors to the environment and infrastructure.

“We’ve developed a five-stage system to identify and track the unhealthy progression of salinisation in our rivers in much the same way we would track an illness or disease like cancer,” Kaushal concluded. “We have to look at this unhealthy ‘Salinisation Syndrome’ from a systems-level perspective if we’re going to develop guidelines for diagnosing harmful levels and treat the problem.”