Medicine

You need to stop doing this with your used contact lenses

You need to stop doing this with your used contact lenses

A recent United States study has revealed that flushing contact lenses down the toilet is contributing to the plastic waste problem. Microplastics - that is, bits of plastics that continually break down into smaller and smaller bits - are a massive problem and contact lenses are only making things worse.

Once flushed away, lenses get in the sanitary sewer system, ending up in wastewater treatment plants and sinking in the sludge.

According to the team of researchers, up to 20 percent of contact lens users flush them down the toilet after use.

The study was presented at the meeting but has not been published or peer-reviewed, which are considered a gold standard in medical and scientific research.

The plastic particles either flow out into the ocean, or become part of sewage sludge, which is often applied to land as fertilizer.

Around 45m people wear contacts in the USA, while rates in other countries vary, with between 5 and 15% of the population in Europe using them.

"We began looking into the USA market and conducted a survey of contact lens wearers". They interviewed workers at municipal sewage plants who confirmed they had seen lenses in wastewater, the researchers told The New York Times.

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Graduate research assistant Varun Kelkar said: "We found there were noticeable changes in the bonds of the contact lenses after long term treatment with the plant's microbes". In fact, the team estimates that at least six metric tonnes of lenses end up in wastewater each year in the US alone.

The issue with lenses is to deal with not only them but their packaging made up of foil and plastic, which has to be separated in order to go to recycling plants, said Rick Zultner, director of process and product development for TerraCycle.

Well, you shouldn't flush them down the toilet or wash them down the sink. Moreover, the plastics used in contact lenses are different from other plastic waste, such as polypropylene, which can be found in all items from textiles to vehicle batteries. 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 auto batteries to textiles. They may be eaten by some aquatic organisms which mistake them for actual food and they can end up hurting a large segment of the food chain as they pass from one animal to another.

"When the plastic loses some of its structural strength, it will break down physically". These microplastics can not be filtered out of the waste water unlike larger plastic particles.

They hope their work will determine industry to at least provide labels on the lenses' packages describing how to properly dispose of the devices - placing them alongside other solid waste.

Even better he said would be for manufacturers to make it easier to recycle plastic contact lenses.

This article has been republished from materials provided by the American Chemical Society.