According to a new study, humans are contributing to an increase of salt in the water and air. “We have more salt in our rivers and streams than we’ve ever had,” said Megan Rippy, assistant professor of civil and environmental engineering at Virginia Tech and one of the authors of a new study.
She and other researchers compiled data from around the world to find out how much salt is getting into drinking water, and what’s leading to the increase.
Rising salinity in freshwater isn’t an issue most people are aware of, but it is an increasing risk to agriculture and drinking water.
Rippy said increased salt mining and production of sodium products is largely the cause. In addition to the salt we eat, salt is used in fertilizers in agriculture. Even some household items, like dishwashing soap and laundry detergent have sodium, which drives up the salinity in water.
“There’s a lot of salts added as bulking agents in powders, so powdered detergents, versus, say, a liquid detergent,” Rippy said.
Another cause is deicing salt we put on our roads during winter. “Often we can apply less salt than we do,” Rippy said.
Salt naturally cycles through the ground, water and air. But now, what would normally take millions of years to accumulate, has occurred in decades, says Stanley Grant, another researcher who worked on the study.
“And so we’re accelerated the rate at which that salt is being exposed and released,” Grant said.
He added that road salt for deicing produces the highest peak concentrations of salt in drinking water, although it’s not the highest overall contributor of salt in the air or water.
In some Northern Virginia communities, where rising salinity is an increasing concern, some water utility companies are asking residents to use less deicing salts during the winter.
Rippy said more research is needed to better understand what's creating the highest sources of salt contamination, and how to reduce it, particularly in some places in Africa, Asia and South America, where Rippy said there are knowledge gaps.
Their article was published in the journal “Nature Reviews Earth & Environment.”
