by It seems wherever scientists look for plastic, they find it: from the ice in Antarctica, to the first bowel movement produced by newborn babies.
Now, researchers are discovering that the amount of microscopic plastics floating in bottled drinking water is far greater than first believed.
Using sophisticated imaging technology, scientists at Columbia University’s Lamont-Doherty lab examined water samples from three popular brands (they won’t say which ones) and found hundreds of thousands of bits of plastic per liter of water.
Ninety percent of those plastics were small enough to qualify as nanoplastics: microscopic particles so small that they can be absorbed into human cells and tissues, as well as cross the blood-brain barrier.
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The research, published Monday in the journal Proceedings of the National Academy of Sciences, raises new concerns about the potentially harmful health effects – and prevalence – of nanoplastics. The researchers found that the quantity of such particles was 10 to 100 times greater than previously estimated.
“For a long time before this study, I really thought what was in bottled water [in terms of] the nanoplastics were just a few hundred PET particles,” said Naixin Qian, a Columbia chemistry graduate student and lead author of the study. “It turns out to be much more than that.” PET, or polyethylene terephthalate, is a type of clear plastic commonly used for single-use water bottles.
Microplastics – particles between 1 micrometer and 5 millimeters in size – have been documented in bottled and tap water for several years. But the identification of nanoplastics – particles measuring only billionths of a meter – is raising alarm.
The very small size of nanoparticles allows them to behave differently than larger pieces of material, it was said Beishan YanColumbia environmental chemist and co-author of the study.
Pollutants and pathogens can be carried on the surface of a particle, and the smaller a particle gets, the higher its surface area-to-volume ratio becomes.
As a result, Yan said, “even if they are not so toxic at a larger particle size, when they get smaller they become toxic, because they can affect the cells, in the tissues, within the organisms. “
Research into the effects of plastic on human health is still in its infancy. It is only recently that scientists have recognized the presence of plastics in human bodies and organs.
But research on other animals suggests a strong negative impact on health. In laboratory studies on fish and rodents, microplastics have been shown to affect development, reproductive capacity and health, gut health, hormone levels, immune responses, the heart and more.
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The authors of the study used a new type of microscope that uses a laser to image the vibrations of the molecules to analyze the nanoparticles against a library of seven common plastics. They were not surprised to find small pieces of PET, as that is what the bottles were made from. However, the amount of PET was worsened by the amount of polyamides, a type of nylon used in the reverse osmosis filters that the water is run through before bottling.
Other plastics found in the water in microscopic quantities include polystyrene, polyvinyl chloride and polymethyl methacrylate, also known as plexiglass. But only 10% of the nanoparticles analyzed could be classified as one of those seven known plastics, the researchers found. The origin of the rest is unknown.
Over the past several years, researchers have identified microplastics from the deepest ocean waters to the snow tops of the world’s highest mountains. They have found it in human blood, lung tissue and brain, and in organisms from worms and zooplankton, to whales and polar bears.
In some cases, the particles are ingested with food and water. In other cases, they are inhaled – scientists have found them in outdoor and indoor air, as well as in clouds – or absorbed through the skin.
The laundering of synthetic clothing and the breakdown of car tires are two of the biggest sources of airborne plastics.
“As humans, we live in environments where plastic is everywhere,” said Yan.
There is also evidence that these small particles bioaccumulate, or become more concentrated as they move up the food chain from one organism to the next.
Although the Columbia study did not analyze tap water samples, previous studies of microplastics found much lower concentrations of these particles in tap water than in bottled water.
Food packaging is also a known source of plastic contamination in food. On January 4, Consumer Reports released the results of a investigation into plastic chemicals in common processed foods widely available in the US
Plastic chemicals and nanoplastics are part of the same problem, but they’re two completely different animals,” said James E. Rogers, a microbiologist who is acting director of product safety at Consumer Reports. “One is a chemical and one is a physical piece, even if it’s micro-sized.”
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Of the 85 food products tested, 84 contained traces of phthalates, the most common type of chemical used to make plastic more durable. Almost 80% of the foods contained bisphenols, another industrial chemical.
Phthalates and bisphenols are known endocrine disruptors, meaning they disrupt the body’s hormonal systems. Exposure to these chemicals over time is associated with higher risks of diabetes, obesity, cancers and fertility problems, Rogers said.
“You may not be able to achieve zero exposure, but at least you can reduce your risk by reducing your exposure,” Rogers said. “Cut out the fast food. Eat less processed foods. Eat less fat.”
Now that they’ve given us the bottled water, the Columbia team is looking at how else they can use Raman scattering microscopy to look for nanoplastics in other areas of life.
One project looks at nanoplastics in exhaust and wastewater from commercial and residential washers and dryers. A pair of British Foreigners The team is currently collecting snow samples while hiking across Antarctica to analyze them. The Columbia team is also collaborating with other research institutions to measure nanoplastics in human tissues and try to understand their effects on health.
And a group at the University of Waterloo, in Canada, is using artificial intelligence to help sort through the bits of plastic they find in wastewater – providing a brand new, potentially more powerful and accurate way to different types and often difficult to identify. plastic in water samples.
“It’s an example of using AI for good,” said Wayne Parker, a professor of Civil and Environmental Engineering at the school.
Methods like AI, or the technology used by the Columbia team to identify micro- and nanoplastics, will allow researchers to better identify and assess “the risks of these particles” in the environment and in ourselves, Parker said.
This story originally appeared in the Los Angeles Times.
