Researchers in the U.S. are warning those who wear contact lenses to be more careful of how they dispose of the product.
A recent study published by Arizona State University looked at the journey that disposable contact lenses take once they’re thrown out.
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It highlighted that while lenses may offer convenience to those temporarily ditching glasses, they pose a problem when it comes to plastic pollution in bodies of water.
According to the U.S. Centers for Disease Control and Prevention, 45-million people wear contacts in America. The study notes that leads to 14-billion lenses being thrown out each year in the country.
About 15 to 20 per cent of the 400 Americans surveyed said they either flush their lenses down the toilet or let them drain in the sink, rather than throwing them in the trash.
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“This is a pretty large number, considering roughly 45-million people in the U.S. alone wear contact lenses, amounting to 1.8- to 3.36-billion lenses flushed per year, or about 20–23 metric tons of wastewater-borne plastics annually,” one of the researchers, Charles Rolsky, said.
The researchers then looked at several different brands of contact lenses, finding those that go down the drain or toilet end up in wastewater plants and often slip through filter systems. Eventually, lenses break apart into microplastics.
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“For about every two pounds of wastewater sludge, a pair of contact lenses typically can be found,” the study explained, noting that sludge is then used for things such as soil conditioning.
Microplastics left in water may also be eaten by wildlife.
The researchers said they hope contact lenses companies add safe disposal instructions on packaging as a result of this research.
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In the long-term, researchers want contact lenses to be made of degradable materials.
Contact lenses are the latest product receiving attention for having adverse effects on the environment.
Last year, a study out of Carleton University found that the bulk of plastic fragments recovered from the Ottawa River were from microfibres, many of which were coming from clothing.
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“What really surprised us is that we found plastic particles in every single water and sediment sample we took, so the plastic was really prevalent in the river system,” said lead researcher Jesse Vermaire, assistant professor of environmental science, geography and environmental studies at Carleton University.
As much as 95 per cent of the plastic in the water samples collected was made up of microfibres. Around five per cent of the plastic was made up of microbeads.
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Aside from recent research, plastic products such as straws have become flashpoints in a global crusade against water pollution.
Chelsea Rochman, an assistant professor at the University of Toronto who studies pollutants in freshwater, explained that it’s tough to target one plastic product and expect that to solve the problem.
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“Straws are kind of low-hanging fruit — they’re an easy win and that’s fantastic,” she told Global News.
“I just hope that everyone realizes that’s one step of many and there is no silver-bullet solution to plastic pollution.”
United Nations figures show nearly nine-million tonnes of plastic — bottles, packaging and other waste — enter the ocean each year, killing marine life and entering the human food chain.
— With files from Global News reporter Tania Kohut