Managing salt pollution to protect drinking water resources and freshwater ecosystems

Doctors often tell us, “cut back on your salt.” And just like too much dietary salt is bad for blood pressure, too much salt in our nation’s streams, lakes, and reservoirs threatens ecosystem health and the security of our nation’s drinking water and food supplies. 

“Salt levels are rising fast in freshwaters across the United States,” said Stanley Grant, professor of civil and environmental engineering in the Virginia Tech College of Engineering and the principal investigator of a recent multimillion dollar grant from the National Science Foundation aimed at addressing the issue. “It’s a slow-moving train wreck. If we don’t figure out how to reverse this trend soon, it could become one of our nation’s top environmental challenges going forward.” 

Typical culprits include excessive de-icer use on roads and parking lots during the winter, as well as the discharge of industrial and municipal wastewaters. But putting our nation on a salt diet will not be easy. 

“Reversing freshwater salinization will require changing the way we design and operate our engineered infrastructure, but also changing the everyday choices we all make, from which home products we use, such as detergents, to how much salt to sprinkle on our icy driveway,” said Sujay Kaushal, a co-principal investigator on the NSF grant at the University of Maryland and an international expert on freshwater salinization. “It’s going to require finding new ways to collaborate across disciplinary boundaries – and across the traditional academic/practitioner divide.”

The grant, which provides up to $3.6 million to the researchers over five years, was awarded through the National Science Foundation’s Growing Convergence Research (GCR) program, which aims to catalyze solutions to societal grand challenges by the merging of ideas, approaches, and technologies from widely diverse fields of knowledge to stimulate innovation and discovery.

“Growing Convergence Research is one of NSF’s Big Ten Ideas,” said Megan Rippy, an assistant professor of civil and environmental engineering at Virginia Tech and a co-principal investigator on the project. “Our grant is in the second cohort of research projects funded under NSF’s GCR program, which makes this project all the more exciting.”

Freshwater salinization is just one of many upcoming environmental threats that won’t be easily solved with traditional (top-down regulatory) approaches.

“Emerging environmental challenges, like freshwater salinization, are tough to address because there isn’t much appetite in this country right now for big regulatory fixes, and there is no single ‘bad guy’ to go after. We all contribute to the problem in some small way,” said Thomas Birkland, another co-principal investigator on the project and a professor of public policy at NC State. “It’s a classic ‘tragedy of the commons’ problem. Through our collective actions we unwittingly deplete the very resource that we all rely on for survival.” 

The researchers are borrowing a page from Nobel prize-winning political scientist Elinor Ostrom, who demonstrated, through case studies across the United States and around the world that, under the right circumstances, common pool resources, like drinking water and freshwater ecosystems, can be effectively self-managed by local stakeholders. The team hypothesizes that this “bottom-up” approach to resource management can be catalyzed through convergent research.

“In our case, convergence refers to a process of engaging researchers, government agencies, and other stakeholders in rich deliberations to collectively design and test locally-tailored solutions,” said Todd Schenk, an associate professor in the School of Public and International Affairs at Virginia Tech and a co-principal investigator on the project. “We plan to test this new approach by working with the local communities and institutions to improve salt management in the Occoquan Reservoir, an important drinking water source for Fairfax Water, a water utility serving about 2 million people in Northern Virginia.” 

The NSF award will also help catalyze collaborations between the Occoquan Watershed Monitoring Laboratory, which Grant co-directs, and other research programs at Virginia Tech, as well as at universities, research foundations, and government agencies across the United States and internationally. The laboratory was established in 1972 to serve as an unbiased source of scientific monitoring of the Occoquan Reservoir, the site of the nation’s first deliberate use of reclaimed wastewater to supplement a surface drinking water supply.

“While it’s often hidden from the public eye, freshwater salinization is a serious problem for coastal zones around the world,” said Robert Weiss, director of the Center for Coastal Studies at Virginia Tech, housed within the Fralin Life Sciences Institute, and professor of natural hazards in the Department of Geosciences in the College of Science.

“This team’s transdisciplinary research will benefit communities and society in general and underscores Virginia Tech’s commitment to the principles of the land-grant university in the 21st century.” Experience gained and lessons learned from the project will be upscaled nationally and globally in partnership with The Water Research Foundation.

“From my viewpoint, this project is tailor-made for today’s environmental science and engineering student,” said Grant. “They’re not just interested in solving narrow, technical problems. They really want to see that connection to policy and connection to change. They want to tap into a passion about the future of the planet and become a force for good.” 

Additional faculty on the project include Marc Edwards, University Distinguished Professor in the Department of Civil and Environmental Engineering at Virginia Tech; Jesus Gomez-Velez, an assistant professor at Vanderbilt University; Erin Hotchkiss, an assistant professor in the Department of Biological Sciences at Virginia Tech; and Peter Vikesland, a professor in the Department of Civil and Environmental Engineering at Virginia Tech.

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