An average liter of bottled water contains about a quarter of a million invisible particles of tiny nanoplastics, detected and categorized for the first time using a microscope using dual lasers.
Scientists have long thought there were large quantities of these microscopic pieces of plastic, but they didn’t know how many or what type they were, until researchers at Columbia and Rutgers universities performed their calculations.
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After analyzing five samples of three common brands of bottled waterresearchers found particle levels ranging from 110,000 to 400,000 per liter, with the average being about 240,000, according to a study published Monday in the journal Proceedings of the National Academy of Sciences.
These are particles that measure less than a micron. A micron, also called a micrometer, measures one millionth of a meter (about 25,400 microns per inch). A human hair is about 83 microns thick.
Previous studies analyzed slightly larger microplastics, ranging from 5 millimeters or less than a quarter of an inch – visible to the naked eye – to a micron. The study found 10 to 100 times more nanoplastics than microplastics in bottled water.
Apparently, Much of the plastic comes from the bottle itself and the reverse osmosis filter membrane used to keep out other contaminants, said Naixin Qian, a Columbia physical chemist and lead author of the study.
He did not reveal what those brands are because researchers want to get more samples before identifying a brand and want to study more of them. Even so, he indicated that these are common brands that They can be purchased at stores like Walmart.
Are these particles harmful to health?
Researchers still cannot answer the big question: Are these nanoplastic particles harmful to health?
“That is currently under review. We don’t know if they are dangerous and if so, to what extent,” said Phoebe Stapleton, a toxicologist at Rutgers and co-author of the study. “We know that they enter the tissues (of mammals, including humans)… and current studies analyze what they do in cells.”
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The International Bottled Water Association said in a statement that “there are currently no standardized (measurement) methods or scientific consensus on the potential health impact of nanoparticles. Therefore, media reports about these particles in drinking water do nothing but unnecessarily scare consumers.”
The American Chemistry Council, which represents plastics makers, declined to immediately comment.
The world is drowning under the weight of plastic pollutionwith an annual production of more than 430 million tons”, and by the presence of microplastics in the world’s oceans, in food and in drinking water, some of which come from clothing and cigarette filters , according to the United Nations Environmental Program.
Efforts to reach a global plastics treaty continue after talks hit a dead end last November.
The four co-authors interviewed say they reduced their consumption of bottled water after completing the study.
Wei Min, the physical chemist who pioneered the use of dual-laser microscope technology, said he cut his bottled water consumption in half. Stapleton says he now consumes more filtered water at his New Jersey home.
However, Beizhan Yan, an environmental chemist at Columbia and one of the study’s co-authors, noted that the filters can be problematic because they use plastics, although he also increased his consumption of tap water.
“There’s just no way to win,” Stapleton said.
Other factors of concern
Outside experts who praised the study agree that there is widespread concern about the dangers of small plastic particles, but it is too early to make a definitive statement.
“The danger of plastics themselves remains an unanswered question. To me, the additives are more concerning,” said Jason Somarelli, professor of medicine and director of the comparative oncology group at Duke University, who was not involved in the study.
“We and other researchers have shown that these nanoplastics can enter cells and that they contain all kinds of chemical additives that can cause cellular stress, damage to DNA and modify metabolism or cellular functioning,” he added.
Somarelli stated that, in his study, still unpublished, more than 100 “known carcinogenic chemicals were found in these plastics.”
The worrying thing, according to Zoie Diana, an evolutionary biologist at the University of Toronto, is that “small particles can appear in different organs and can cross membranes that they should not cross, such as the blood-brain barrier.”
Diana, who was not involved in the study, said the new tool used by the researchers makes this an exciting advance in the study of plastics in the environment and in the body.
About 15 years ago, Min invented dual-laser technology, capable of identifying specific compounds through their chemical properties and the way they resonate when exposed to lasers. Yan and Qian talked to him about using that technique to find and identify plastics that were too small for researchers using established methods.
Kara Lavender Law, an oceanographer at the Marine Education Association, declared that “the work is an important advance in detecting nanoplastics,” but said she would like to see other analytical chemists replicate the technique and results.
Denise Hardesty, an Australian government oceanographer studying plastic waste, said context is needed. The total weight of the nanoplastics found “is approximately equivalent to the weight of a penny in the volume of two Olympic swimming pools.”
Hardesty is less concerned about nanoplastics in bottled water than other people, noting that she has “the privilege of living in a place where I have access to ‘clean’ tap water, so I don’t have to buy water to drink in single-use containers.”
Yan said he has begun studying other drinking water sources in Boston, St. Louis, Los Angeles and elsewhere to find out how much plastic is in tap water there. Previous studies to find microplastics, as well as some early studies, suggest that there may be fewer nanoplastics in tap water than in bottled water.
Even though its effect on human health is unknown, Yan recommends concerned people use reusable bottles instead of single-use plastics.
