It seems that wherever scientists look for plastic, they find it: from the ice of Antarctica to the first stools produced by newborn babies.
Now, researchers are discovering that the amount of microscopic plastics floating in bottled drinking water is much higher than initially 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 pieces of plastic per liter of water.
Ninety percent of those plastics were small enough to qualify as nanoplastics: microscopic specks so small that they can be absorbed by human cells and tissues, as well as cross the blood-brain barrier.
The research, which was 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 number of such particles was 10 to 100 times higher than previously estimated.
“For a long time before this study, I thought that what was inside 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 ranging from 1 micrometer to 5 millimeters in size) have been documented for several years in bottled and tap water. But the identification of nanoplastics (particles measuring just billionths of a meter) is ringing alarm bells.
The incredibly small size of nanoparticles allows them to behave differently than larger pieces of matter, he said. Beizhan YanColumbia environmental chemist and co-author of the study.
Contaminants and pathogens can be carried on the surface of a particle, and the smaller a particle becomes, the greater its surface area to volume ratio.
As a result, Yan said, “even if they are not as toxic at a larger particle size, when they get smaller they become toxic, because they can interfere in cells, in tissues and inside organelles.”
Research into the effects of plastic on human health is still in its early stages. Only recently have scientists identified the presence of plastics in people’s bodies and organs.
But research in other animals suggests a strong, negative influence on health. In laboratory studies with fish and rodents, microplastics have been shown to interfere with development, reproductive fitness and health, gut health, hormone levels, immune responses, the heart, and more.
The study authors used a new type of microscope that uses lasers to image the vibration of molecules to analyze the nanoparticles against a library of seven common plastics. They were not surprised to find small pieces of PET, since that is what the bottles were made of. However, the amount of PET was dwarfed by the amount of polyamides, a form of nylon used in reverse osmosis filters that water passes through before bottling.
Other plastics found in water in microscopic quantities include polystyrene, polyvinyl chloride, and polymethyl methacrylate, also known as plexiglass. But the researchers found that only 10% of the nanoparticles analyzed could be classified as one of those seven known plastics. The origin of the rest is unknown.
Over the past few years, researchers have identified microplastics from the deepest ocean waters to the snowy tops of the planet’s highest mountains. They have found it in human blood, lung tissue and the brain, and in organisms ranging 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 indoor and outdoor air, as well as in clouds) or absorbed through the skin.
Laundering synthetic clothing and rotting car tires are two of the largest sources of airborne plastics.
“As people, we live in environments where plastic is everywhere,” Yan said.
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 that analyzed microplastics found much lower concentrations of those 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 published the results of its investigation in plastic chemicals in common processed foods widely available in the US.
Plastic chemicals and nanoplastics “are part of the same problem, but they are two totally different animals,” said James E. Rogers, a microbiologist and acting director of product safety at Consumer Reports. “One is a chemical piece and the other is a physical piece, even if it is micro-sized.”
Of the 85 food products analyzed, 84 had traces of phthalates, the most common type of chemical used to make plastic more durable. Almost 80% of foods contained bisphenols, another industrial chemical.
Both phthalates and bisphenols are known endocrine disruptors, meaning they interfere with the body’s hormonal systems. Exposure to these chemicals over time is associated with increased risks of diabetes, obesity, cancer and fertility problems, Rogers said.
“You may not be able to get to zero exposure, but you can at least reduce your risk by reducing your exposure,” Rogers said. “Eliminate fast food. Eat less processed foods. Eat less fatty foods.”
Now that we’ve been turned off by bottled water, the Columbia team is studying how else they can use stimulated Raman scattering microscopy to look for nanoplastics in other areas of life.
One project analyzes nanoplastics in exhaust gases and wastewater from commercial and residential washers and dryers. A pair of british adventurers Currently, those trekking in Antarctica are collecting snow samples for the team to analyze. The Columbia team is also collaborating with other research institutions to measure nanoplastics in human tissues and try to understand their health effects.
And a group at the University of Waterloo in Canada is using artificial intelligence to help classify the bits of plastic they find in wastewater, providing a novel, and potentially more powerful and accurate, way to identify different and often difficult varieties. 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.
