Visually impaired people use less visible contact lenses as an alternative to more conservative glasses. There are a great many options for contact lenses on the market, but as a rule, this product serves its owner for a very short time - from several months to several days. Then they are usually thrown away. And, as a rule, into the sewers. Don't do that.
According to a report presented by scientists at the annual meeting of the American Chemical Society, 45 million Americans flush up to 10 tons of contact lenses down the drain every year. As a result, it harms the oceans. Pieces of plastic from which lenses are made with wastewater flow into rivers and the ocean, posing a threat to marine life. This plastic can be transmitted along the food chain: from small fish to a larger one, from large fish to representatives of the chain higher in the hierarchy, for example, to predators, the same seals.
Rolf Holden of the University of Arizona, one of the authors of the study, notes that microplastic pieces of contact lenses are found even in tap water. According to him, he has worn glasses and lenses all his life and only recently thought about what happens to the lenses after they are thrown away. He did not find any studies on this topic, so he and his colleagues decided to find out on their own by calculating the volume of lenses that enter the environment.
The authors of the work conducted a survey among Americans, finding out how many people throw lenses where they should not.
“We decided to study the US market and conducted a survey among contact lens wearers. In the end, it turned out that 15 to 20 percent of their users flushed their lenses down the sink or toilet,”says Charlie Rolsky, one of the study's authors.
In the United States, about 45 million people use up to 14.7 billion disposable and reusable contact lenses annually. This means that 6 to 10 tons of lenses can enter US wastewater alone. The authors even calculated the approximate number of contact lenses that end up in the sewer - 2.9 billion pieces.
The researchers also wanted to find out what happens to contact lenses in the wastewater. To do this, they put them in tanks with water from treatment plants, where bacteria live that decompose various pollutants. The lenses were left in the tanks for 14, 96 and 172 hours. As a rule, this is how long the wastewater is usually in these tanks. By the end of their observations, the scientists noted that the lenses had barely begun to decompose. In other words, practically whole lenses and their large fragments get into the soil and water bodies. What's more, lenses are made from materials that can absorb and accumulate toxins from the environment and this poses an additional threat.
Scientists noted that organic polymers contained in contact lenses can get into the food of underwater inhabitants, which millions of years of evolution have not taught to separate natural organic matter from that made by man. Plastic is clearly not the best food. Its entry into the food chain promises troubles to all its further participants, up to the people, on whose table sooner or later seafood will get, which ate someone's "second eyes".
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The authors of the report expressed the hope that the manufacturers of contact lenses will pay more attention to the materials used in their production, as well as methods of their disposal.
Nikolay Khizhnyak