How flushed contact lenses add to microplastic pollution in waterways

Cornelia Mascio
Agosto 20, 2018

Researchers from Arizona State University conducted a study that delved into the proper disposal of contact lenses, and as it turns out, users aren't very good at dealing with lenses once they're done using them. While the researchers also want contact manufacturers to find a way for consumers to easily recycle their products, for now, they recommend throwing them out with solid waste - never send them down the toilet or sink.

Even if the whole contact lens does not escape through waste water filters, the fragments of them can be unsafe, too, contaminating the environment.

Millions and millions of Americans put on contact lenses each day, but majority probably aren't aware that these thin circular strips of plastic pose great harm to the environment.

The lenses are consequently spread on farmland as sewage sludge, increasing plastic pollution in the environment.

And there were small changes in the bonds of the plastic polymers after exposure to the microbes.

Now a research team based in the USA has shown for the first time how they can get eaten by fish and other marine life and be returned to us on our plates.

Rolf Halden, director of the Biodesign Center, pointed out that contacts are only a small portion of the plastic waste that ends up in the ocean, and are arguably more important to people than other disposable items like plastic bags or straws.

The findings, which were presented at the 256th National Meeting & Exposition of the American Chemical Society, illustrate a growing environmental hazard rooted from something that seems so harmless.

Of an estimated 45 million United States contact lens wearers, that's around 9 million right there.

"We found that 15 to 20 percent of contact-lens wearers are flushing the lenses down the sink or toilet", he said.

To make matters worse, because contact lenses are typically denser than water, they can sink into aquatic zones and be eaten by marine life thriving down there, which can potentially poison them.

'But I started to wonder, has anyone done research on what happens to these plastic lenses?' What is more, contact lenses are different from plastics used in other products, such as polypropylene, found in everything from auto batteries to textiles. These animals are part of a long food chain. So, it's unclear how wastewater treatment affects contacts. Contact lenses are instead frequently made with a combination of poly (methylmethacrylate), silicones and fluoropolymers to create a softer material that allows oxygen to pass through the lens to the eye.

Some eventually find their way to the food supply, which could lead to people being exposed to plastic contaminants and pollutants that stick to the surfaces.

Wastewater treatment facilities in the USA simply don't do a good enough job of filtering out the tons of contact lenses that are disposed of through the sewer system, according to new research presented Sunday at the American Chemical Society's meeting in Boston.

The researchers broke the study into three core parts.

Dr Halden added: 'Ultimately, we hope manufacturers will conduct more research on how the lenses impact aquatic life and how fast the lenses degrade in a marine environment'.

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