Nanotech beads track the path of environmentally dangerous storm-water runoff

Tabatha Lewis ’18 has teamed up with Engineering and Geoscience Professor Thomas Boving to use microscopic glass beads to track the path of storm water runoff—sediment and grime—that washes off roads and can damage the environment.

With more than 4 million miles of roads in the United States, it’s critical to know what contaminants are in road runoff, and how far they’re traveling on abutting land. Lewis says there is no reliable system in place now to track runoff.

“We intend to change that through our experiment,” says Lewis, a native of Brookfield, Conn. “And, so far, it looks promising.”

The project started in July, when Lewis placed microbeads—in three different sizes—at six sites along Plains Road. The microbeads are the size of natural soils and mimic their movements, which allowed Lewis to track the microbeads in ditches.

“The number of microbeads we released was about 130,000 at each site,” says Lewis, an environmental science major. “We take samples every two or four weeks to determine how far the beads moved.”

So far, Lewis has collected five sample rounds from the ground. The data is translated into computerized “plume maps” that show what’s happening.

“I’m very excited about our results,” says Lewis. “The plume gets bigger as the microbeads move across the land. This is what we predicted.”

Lewis says the project will continue with other URI students for the next few years. In the future, engineers could use the microbeads to trace runoff that is potentially hazardous to streams or lakes nearby. Microbeads could also be used to trace oil spills on roads and highways.

“People don’t realize how damaging road runoff can be to surrounding waterways and lands,” says Lewis. “Road toxins can kill fish, harm plants and leach into the groundwater, so it’s important we understand the movement of these contaminants.”

Lewis’s preliminary results were presented this fall at the Showcase of Undergraduate Research, Scholarly and Creative Works on the Kingston campus. •