If you’re replacing your old contacts with new ones, think twice before you flush your old lenses down the toilet or toss them down the sink. Worn out contacts belong in the garbage can.
For important environmental reasons, contact lenses should not have any role in our wastewater systems. Unfortunately, according to a recent study by Arizona State University, about 20 percent of America’s 45 million contact lens wearers don’t turn to the garbage can when they’re throwing away their old contacts – and the impact on our natural waterbeds has been significant.
“This began as an exploratory venture but we have information to support the fragmentation of contact lenses into microplastics within a wastewater treatment plant,” Arizona State University graduate student Charles Rolsky, the study’s co-author, told Inverse.
Each year, an estimated six to 10 metric tons of plastic contact lenses burden wastewater systems in the U.S. The problem is, when contact lenses are included in wastewater, they dissolve into tiny particles when they are treated at the plant because they are made of a soft plastic.
The end result is that contact lenses have become a major source of what’s called “microplastic pollution.”
The Dangers of Microplastic Pollution
While we’ve long known that plastic pollution has devastating effects on marine wildlife and ecosystems, scientists are just beginning to explore the extent of its impact in its microscopic form. When it leaves wastewater treatment plants, this particle pollution cannot be filtered out like other plastics, so it easily makes its way into the food chain.
In our natural waterways, microplastics from contacts are heavier than water, so they sink to the bottom. There, they are consumed by bottom-feeding wildlife, which can suffer toxic effects.
“Contact lens users should not feel ashamed to use contacts, as they are of high value and very effective,” Rolsky told Inverse. “But used contacts should be disposed of in the trash can instead of down any drain.”