Contact lenses are made with a combination of poly (methyl methacrylate), silicones and fluoropolymers to create a softer material that allows oxygen to pass through the lens to the eye, unlike polypropylene, that can be found in everything from vehicle batteries to textiles.
The team sifted through wastewater sludge, and found several fragments of contact lenses, which indicated that wastewater processing doesn't just let the lenses through - it also appears to help them break into smaller bits.
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 study's lead, Rolf Haden, was inspired to research contact lenses' impact on the environment based on his own personal use of them. "This leads to smaller plastic particles which would ultimately lead to the formation of microplastics", said Kelkar. Now, scientists are reporting that throwing these lenses down the drain at the end of their use could be contributing to microplastic pollution in waterways.
The calculation of how many lenses end up in our wastewater plants and habitat hinged on a variety of data sources. The team presented their findings at the 256th National Meeting and Exposition of the American Chemical Society in Boston, this Sunday.
Roughly 45 million people in the United States alone wear contact lenses, amounting to at least 13 billion lenses worn each year.
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'With the toilet, although it might be tempting you shouldn't flush wet wipes, kitchen roll or anything other than toilet roll down the loo, ' Michelle Ringland, head of marketing at Lanes Group tells Metro.co.uk.
They found that, even after extended periods of time, the lenses remained intact.
"We found that 15 to 20 per cent of contact wearers are flushing the lenses down the sink or toilet", said Charlie Rolsky, a PhD student at ASU.
Not only that, but the plastic used in contact lenses differs from other waste, such as polystyrene, which is one of the most commonly used and recycled plastics. These animals belong to a long food chain.
'The same also goes for things like toilet roll inner tubes, cotton buds, contact lenses and dental floss. "The minimum object size for recycling in 40mm, which is why some items like plastic straws and small soy sauce bottles that come in sushi packs can not be recycled". This creates a clear pathway where macro-and microplastics from contact lenses can enter land ecosystems.
"We found that there were noticeable changes in the bonds of the contact lenses after long-term treatment with the plant's microbes", says coauthor Varun Kelkar. Thankfully, unlike most types of environmental pollutions, this one has an incredibly simple solution: chuck contact lenses in the bin, don't flush them down the drain.
Halden's team were already researching plastic pollution and they were unable to find any paper on the subject of what happens to lenses after people are done with them.