Water reacts with plastics to create harmful particles, study finds
The chemical reactions create hydroxyl radicals, unstable molecules linked to aging and disease.
A new study has found that water can react with common plastics to create particles harmful to human cells. The research, published Thursday in the journal Nature, showed chemical reactions between water and six types of fossil fuel-based plastic damaged red blood cells and proteins in lab tests. These reactions produce unstable molecules called hydroxyl radicals, which are linked to aging and disease. As plastic breaks down into microplastics and nanoplastics inside the body, the potential danger increases, said study co-author Wei Min, a chemist at Columbia University.
"Is this phenomenon 5% responsible or 90% responsible for the health effects we are seeing, I can’t answer," Min said. "But I would be surprised if it doesn’t play any role." The study suggests a mechanism that could explain why other research has linked microplastics to inflammation, a driver of many diseases. Human blood is about 50% water and cells are up to 80% water, Min noted, making it impossible to prevent these internal reactions.
Polyethylene and polypropylene, used widely in food containers, packaging and bottle caps, produced the highest levels of hydroxyl radicals in the tests. Min said this finding could lead to certain plastics being reformulated or removed from consumer products. The study was co-authored by researchers from Columbia University, the University of California Berkeley and Rutgers University. "This challenges the reigning theory that plastic is inert," said Sherri "Sam" Mason, a chemist at Gannon University who studies plastic pollution. Mason, who was not involved in the study, said it highlights the need for truly biodegradable plastics. She was among the first researchers to find microplastics throughout the Great Lakes, a source of drinking water for 40 million people in the U.S. and Canada.
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Scientists are finding microplastics in nearly every part of the human body, including the brain, heart and reproductive organs. Emerging research suggests ingesting or inhaling these particles may contribute to heart disease, dementia, fertility problems and premature births. "Our bodies have natural defense mechanisms," said study co-author Phoebe Stapleton, a Rutgers professor of pharmacology and toxicology. "But depending on other exposures we’ve had, our genetics and lifestyle choices, all of these (hydroxyl radicals) could build up to a point where we can’t handle them anymore."
More than 8 billion tons of plastic already pollute the Earth, and manufacturers plan to triple production by 2060. Craig Davis of the American Chemistry Council said the study "offers a novel look at microplastics outside the body." Davis said it does not prove the effects happen inside the body or at real-world exposure levels, and that such gaps matter before drawing conclusions about human health. Min acknowledged the study's limitations but said it should guide future research.
With files from Chicago Tribune