Most municipalities rely on road salts to melt ice and keep roadways safe; however, researchers at Virginia Tech and Towson University in Maryland are concerned that the chemicals are not being effectively absorbed and may be reaching waterways. The research team completed a study, published in Environmental Science and Technology, to determine how well current stormwater management practices mitigate the effects of road salts and how those salts might be impacting waterways.

“We know that surface waters in many areas are becoming more saline and that salt levels have been rising steadily for at least the past 30 years in reservoirs that provide water for Baltimore,” said Professor Joel Snodgrass. “However, we know little about the effectiveness of stormwater management practices in reducing inputs of salt to surface waters.”

Snodgrass explained that if the stormwater ponds were working effectively, his team could test the groundwater between the ponds and streams and find very little sodium chloride, the chemical used in road salt. The researchers instead discovered that routing runoff contaminated with road salts to stormwater ponds actually resulted in plumes of highly contaminated groundwater moving from ponds to streams.

“Current stormwater management practices may help slow the movement of road salts to streams, but they don’t completely stop it from getting there,” he said. “On top of that, the road salts are entering these bodies of water in a fashion that causes salt levels in streams to remain elevated year-round.” These elevated levels can have negative impacts on both wildlife and human health.

According to Snodgrass, the solution is complicated. He and his team plan to continue researching how road salts and other chemicals affect wildlife and the environment, while other researchers are exploring the effectiveness of alternatives to road salt and their potential environmental implications. “We’re looking at the balance sheet between economics and the environment and human health,” Snodgrass said. “This is a complex problem that’s going to take an interdisciplinary team to tackle.”

Read the full press release.