Applying salt to roadways lowers the freezing point of water and prevents slippery surfaces, which makes it safer for people to drive in wintry conditions. In the U.S., more than 22 million tons of road salt is spread every year.
But road salt harms infrastructure and the environment. In fact, road salt damages cars and metal infrastructure by accelerating rust and corrosion. Road salt can also leach into soil and waterways, disrupting ecosystems, degrading soil, contaminating water, and damaging vegetation.
In cities and towns, road salts often wash into stormwater systems, posing health concerns and challenges for infrastructure.
A new study led by researchers from Virginia Tech looked at how salt affects plants and whether certain plants could mitigate salt pollution. The research team studied stormwater detention basins in Northern Virginia, examining the impacts of road salt on plants, soils, and water quality in green infrastructure systems.
The findings, which were recently published in the journal Science of the Total Environment, found that the amount of salt present in green infrastructure systems does reach levels that threaten plant communities. However, the researchers found that relying on salt-tolerant plants for mitigation is unlikely to be effective because they simply don’t take in enough salt.
Certain plants, particularly cattails, absorbed substantial amounts of salt. But even in a basin densely planted with salt-tolerant cattails, only up to 6% of the road salt applied during winter could be removed.
Plants alone cannot solve our salt pollution problem.
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Researcher studies the power of native plants to combat road salt pollution
Photo, posted January 22, 2025, courtesy of the City of Greenville, North Carolina via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio
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