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According to a new study, a typical one-liter (33-ounce) bottle of water contains an average of about 240,000 plastic pieces. The researchers determined that many of those fragments had been historically unknown, suggesting that the health concerns associated with plastic pollution may be dramatically underestimated.
The peer-reviewed study, published Monday in the journal Proceedings of the National Academy of Sciences, is the first to evaluate bottled water for the presence of “nanoplastics” — plastic particles less than 1 micrometer in length, or one-seventeenth the width. . human hair. The findings suggest that bottled water may contain up to 100 times more plastic particles than previously thought, as earlier studies had only found microplastics, or fragments between 1 and 5,000 micrometers in size.
Nanoplastics pose a greater threat to human health than microplastics because they are small enough to penetrate human cells, enter the bloodstream and affect organs. Nanoplastics can also pass into the bodies of unborn babies through the placenta. Scientists had long suspected their presence in bottled water, but lacked the technology to identify individual nanoparticles.
To overcome that challenge, the study’s co-authors invented a new microscopy technique, programmed a data-driven algorithm, and analyzed approximately 25 1-liter bottles of water purchased from three popular brands in the U.S. Used both to do. (The researchers declined to specify which brands.) They found 110,000 to 370,000 tiny plastic particles in each liter, 90% of which were nanoplastics.
“This study provides a powerful tool to address challenges in the analysis of nanoplastics, promising to bridge the current knowledge gap on plastic pollution at the nanoscale,” says Naixin Qian, lead author of the study and graduate student at Columbia University. Is.” chemistry.
“At first it was just a dark area, unknown. Toxicity studies were just guessing what’s in there,” says Beizan Yan, a study co-author and environmental chemist at Columbia University. “It opens a window where we can see a world that hasn’t been exposed to us before.”
The researchers targeted seven common plastic types, including polyethylene terephthalate (PET), from which many water bottles are made, and polyamide, which is often used in filters to purify water before bottling. But they also discovered many unknown nanoparticles in the water. If any of them are nanoplastics, the prevalence of plastics in bottled water could be even higher.
The world produces more than 450 million tons of plastic each year, most of which ultimately ends up in landfills. Most plastic does not degrade naturally, but instead breaks down into smaller pieces over time. Small plastic fragments are also routinely released from plastic-containing products during use, including many synthetic fabrics.
While plastic pollution is present everywhere on Earth, bottled water is of particular interest to scientists because of its potential for plastic particles to enter the human body. A study published in 2022 found that the concentration of microplastics in bottled water was higher than in tap water. A 2021 report warned that opening and closing the lid of a plastic water bottle could release small pieces of plastic into the liquid.
The co-authors of the latest study say their research won’t stop at bottled water. They also plan to examine nanoplastics in tap water and snow samples collected from West Antarctica. “There is a vast world of nanoplastics to be studied,” said Wei Min, another co-author and biophysicist at Columbia University. “The smaller things are, the more easily they can get inside us.”
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