The U.S Center for Disease Control and Prevention states that about 45 million Americans wear contact lenses. Each year Americans dispose of 2.6 to 2.9 billion contact lenses by flushing them or putting them down the drain. Arizona State University put together a study to determine how contact lenses harm our waters and animals. This is the first study providing an estimate of the potential burden these tiny plastics can have.
Charles Rolsky, an ASU doctoral student who lead the study, was inspired by the recent interest in single use items such as straws, silverware and plastic bags. To begin the research Rolsky placed contact lenses in waste water treatment tanks filled with microorganisms that were eager to pray. After brewing in the tanks for 14, 96 and 172 hours they discovered that the lenses had only begun to degrade after 172 hours.
The inability for these lenses to break down has lead the researchers to the conclude that as much as 23,000 kilograms of lenses (about 50,000 pounds) may accumulate in sewage sludge in the U.S. each year. And with 55 percent of waste being dumped into soils, the researchers estimate that 11,000 to 12,650 kilograms (about 24,000 to 28,000 pounds) of contaminant-harboring contact lens fragments end up in U.S. dirt per year.
Americans wear 13.2 to 14.7 billion contact lenses a year and a majority of those users do not dispose of them properly. The next part of the study was a 400-person survey finding that 21 percent of users dispose of their lenses in the toilet or sink. These findings helped them reach their estimate that more than 2.5 billion lenses reside in our sewage in a given year. Once the sewage containing contact fragments reaches soil – rain washes them into rivers and oceans. Once these fragments are in the ocean tiny fish and jellyfish commonly mistake them for food. When these microplastics persist in the environment they can be consumed by animals, birds or insects and make their way into the food chain.
Although contact lense pollution is currently overshadowed by the eight million metric tons of larger plastic that disrupt our oceans – it is still a big issue that should be tackled before it is too late.
If you or anyone you know wears contacts the first piece of advice you can give them is to dispose of your lenses with solid waste rather than down the sink or toilet.