Researchers at Arizona State University warn that throwing away contact lenses down the drain or in the toilet is adding to the pollution of water. Their advice is to throw them away in the garbage can because if they reach the waterways through drains, they contribute to microplastic pollution.
According to the director of the Center for Environmental Health Engineering at ASU’s Biodesign Institute, Rolf Halden, there are many contact lenses used in the U.S.:
“We know that between seven and about 15 billion (soft plastic) lenses are being used in the U.S. every year, and the number actually goes up year by year because more and more people use the daily lenses.”
He knows that there can be an accidental fall of a lens in the toilet or sink as it is removed, but a great majority of users “just flush them because they have no instructions on what to do with them,” he said.
1 in 5 People Flush Contact Lenses Down the Sink or Toilet
The gathered a team to ask people in Arizona who wear contact lenses how they dispose of the ones they used. One in five participants in a study on 400 people was found to flush the lenses down the sink or toilet.
Varun Kelkar and Ph.D. student Charles Rolsky are members of the ASU team, the latter stating that the results of the study were concerning:
“This is a pretty large number, considering roughly 45 million people in the U.S. alone wear contact lenses.”
Once flushed away, lenses get in the sanitary sewer system, ending up in wastewater treatment plants and sinking in the sludge. The team collected parts of the lenses from the sludge and analyzed them. The treatment plants didn’t change them at molecular levels, making them more likely to gather toxic compounds, explains Halden:
“The plastics may have the capacity of soaking up contaminants, and so the plastic shards … they’ll likely be loaded with toxic chemicals, like heavy metals, PCBs [polychlorinated biphenyls] and other things.”
Where do these lenses get after the sludge is removed from treatment plants?
Halden says that the most common way is to apply them on land, “which is done to about 55 per cent of all the biosolids produced in the United States.”
The plastic ends up entering the food chain through earthworms, it gets into rivers and oceans when it rains, or it gets directly to waterways when treatment plants experience overflows.
The team concluded that each year, there are about 6-10 metric tons of plastic lenses that are released in the U.S wastewater.
Andre Blair s is the lead editor for Advocator.ca. He holds a B.A. in Psychology from the University of Toronto, and a Master of Science in Public Health (M.S.P.H.) from the School of Public Health, Department of Health Administration, at the University of North Carolina at Chapel Hill. Andre specializes in environmental health, but writes on a variety of issues.