The average liter of bottled water contains almost a quarter of a million invisible particles of tiny nanoplastics, detected and classified for the first time by a microscope using dual lasers.
Scientists have long predicted that there are large numbers of these microscopic pieces of plastic, but they never knew how many or what kind there were until researchers at Columbia and Rutgers universities did their calculations. Looking at five samples from each of three commonly used brands of bottled water, researchers found that particle levels ranged from 110,000 to 400,000 per liter, with an average of around 240,000, according to a study published Monday in the Proceedings of the National Academy of Sciences.
These are particles smaller than one micron in size. There are 25,400 microns (also called a micrometer because it is one millionth of a meter) in an inch. Human hair is approximately 83 microns wide.
Previous studies have examined slightly larger microplastics, ranging from visibly 5 millimeters (less than a quarter inch) to one micron. The study found that bottled water contained approximately 10 to 100 times more nanoplastics than microplastics.
The study’s lead author, Columbia physical chemist Naixin Qian, said most of the plastic comes from the bottle itself and the reverse osmosis membrane filter used to keep out other contaminants. He did not disclose the three brands because the researchers want more samples and want to examine more brands before choosing one. Still, he said, they are common and purchased at WalMart.
Researchers still can’t answer the big question: Are these nanoplastic pieces harmful to health?
“This is currently being studied. We don’t know if it’s dangerous or how dangerous it is,” says Phoebe Stapleton, a toxicologist at Rutgers and co-author of the study. “We know they get into tissues (of mammals, including humans) … and current research shows what they do in cells.” He watches what they do.”
The International Bottled Water Association said in a statement: “There is currently both a lack of standard (measurement) methods and a lack of scientific consensus regarding the possible health effects of nano- and microplastic particles. Therefore, media reports about these particles in drinking water are likely to unnecessarily scare consumers.” “It doesn’t serve any other purpose.”
The American Chemistry Council, which represents plastic manufacturers, declined to immediately comment.
According to the United Nations, the world is “suffocating under the weight of plastic pollution, with more than 430 million tonnes of plastic produced annually” and microplastics found in the world’s oceans, food and drinking water, some of which comes from clothing and cigarette filters. Nations Environment Programme. Efforts towards a global plastics agreement continue after negotiations reached an impasse in November.
All four co-authors interviewed said they reduced their use of bottled water after conducting the study.
Columbia physical chemist Wei Min, who pioneered dual laser microscope technology, said it has cut bottled water use in half. Stapleton said he now relies more on filtered water at his home in New Jersey.
However, study co-author Beizhan Yan, a Columbia environmental chemist who has increased the use of tap water, pointed out that filters themselves can create problems when they start using plastic.
“There’s no gain,” Stapleton said.
Outside experts who praised the study agree that there is general unease about the dangers of fine plastic particles, but it is too early to say anything definitive.
“The danger of plastic is still an open question. “To me, additives are the most concerning,” said Jason Somarelli, a Duke University professor of medicine and director of the comparative oncology group who was not part of the research. “We and others have shown that these nanoplastics can be internalized into cells, and we know that nanoplastics carry all kinds of chemical additives that can cause cell stress, DNA damage, and alter metabolism or cell function.”
Somarelli said his own study, which has not yet been published, found more than 100 “known cancer-causing chemicals” in these plastics.
What’s troubling is that “tiny particles can show up in different organs and cross membranes they’re not meant to cross, like the blood-brain barrier,” said Zoie Diana, an evolutionary biologist at the University of Toronto.
Diana, who was not part of the study, said the researchers’ new tool makes this an exciting development in the study of plastics in the environment and the body.
About 15 years ago, Min invented dual laser microscopy technology that identifies specific compounds based on their chemical properties and how they resonate when exposed to lasers. Yan and Qian talked with him about using this technique to find and identify plastics that are too small for researchers using established methods.
Kara Lavender Law, an oceanographer at the Marine Education Association, said the “study could be a significant advance in the detection of nanoplastics” but said she would like to see other analytical chemists replicate the technique and results.
Denise Hardesty, the Australian government’s oceanographer who studies plastic waste, said context was needed. The total weight of the nanoplastic found was “roughly equivalent to the weight of a single penny in the volume of two Olympic-sized swimming pools.”
Hardesty is less concerned than others about nanoplastics in bottled water, noting: “I have the privilege of living in a place where I have access to ‘clean’ tap water and don’t have to buy drinking water in disposable containers.”
Yan traveled to Boston, St. Louis to see how much plastic was in tap water. He said he has begun examining other municipal water supplies in St. Louis, Los Angeles and elsewhere. Previous studies investigating microplastics and some early tests suggest that tap water may have less nanoplastics than bottled water.
Yan said that although there are unknowns about human health, he has advice for people who are concerned: Use reusable bottles instead of single-use plastics.
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