Applying salt to roadways is a safety necessity in areas with icy winter climates such as Minnesota and Canada, but doing so comes with damaging effects to infrastructure and the environment.
Researchers from Carlton University in Ottawa, Canada, have been investigating a deicer from South Korea as a possible alternative. The product shows promise, but its environmental impacts need to be more fully tested.
South Korean company Starstech produces a deicing product called EcoST. Although it primarily consists of chloride, EcoST also contains a small amount of calcium carbonate, which the company sources from an invasive species of starfish, Asterias Amurensis (Northern Pacific Seastar). The company claims that the calcium carbonate binds to and controls the release of chloride ions through the process of electrostatic attraction, which in turn prevents chloride from damaging local ecosystems and mitigates its corrosive effect on infrastructure.
Another advantage of EcoST is that it is relatively inexpensive, costing about $24 for 11 pounds.
To assess whether the product performs as advertised, PhD student Mitchell Lawlor from Carlton University’s Department of Civil and Environmental Engineering tested EcoST’s performance as a deicer in work that was sponsored by Starstech.
In 2023, Lawlor ran corrosion tests on six different samples of EcoST (each with a different percentage of the starfish extract). He mixed each sample with water to form a liquid brine, then placed a piece of steel rebar in each sample. Once a week for four weeks, the rebar was weighed to determine how much mass had been lost to corrosion.
Overall, results were positive; the rebar submerged in traditional rock salt lost significantly more mass to corrosion than the EcoST samples.
In 2024, Lawlor ran a series of “ice-melting” and “ice penetration” tests to determine whether EcoST could melt ice as effectively as traditional rock salt. These results were less dramatic—there was only slight variation from one sample to the next—but EcoST samples generally performed at least as well as, if not slightly better than, rock salt.
“The results from this study show that alternative deicers have a very promising future in terms of efficiency,” Lawlor said.
More testing is needed before EcoST can be fully recommended as an alternative deicer. During the corrosion study, for example, EcoST tended to form a white, powdery coating that must be identified and evaluated for environmental impacts. Starstech’s claim that EcoST is more environmentally friendly than rock salt will also need to be evaluated, and EcoST must be tested in a field environment as well.
Kamal Hossain, an associate professor at Carlton University and Lawlor’s project advisor, agreed about the need for more thorough testing. Hossain presented Lawlor’s research at the 2024 annual Salt Symposium. “We need to see the environmental impact of this new product to make a better conclusion,” he said.
—Sophie Koch, contributing writer