A study published in Nature reveals that microplastics generate reactive oxygen species when exposed to water, challenging the notion that plastics are chemically inert and linking them to potential health risks like oxidative stress and inflammation.
For decades, plastics were considered chemically inert, but a study led by Wei Min, a Columbia University chemist, and published in Nature, shows that microplastics interact with water to produce highly reactive radicals. These molecules, detected in lab experiments, could damage cells and proteins, raising concerns about their impact on human health.
Microplastics Generate Reactive Radicals in Water
The research, conducted with colleagues, found that hydrophobic plastics—those that repel water—exhibit the strongest chemical reactivity. When microplastics like polyethylene and polypropylene break down in water, their increased surface area triggers the formation of hydroxyl radicals. The biggest surprise was that plastics, long considered chemically inert, could generate highly reactive radicals simply by coming into contact with water,
Min said in an interview with Earth.com.
Experiments using polystyrene powder and water showed that reactive oxygen species (ROS) degraded a yellow dye, methyl orange, over 10 days. Electron spin resonance confirmed the presence of hydroxyl radicals, while fluorescent sensors detected their accumulation on plastic surfaces. Our cells are 60 to 70 percent water, and therefore this effect could be ubiquitous,
Min noted.
The study’s methodology involved using a Bruker ELEXSYS E500 EPR spectrometer under specific conditions: microwave power 20.23 mW; 12 scans averaged; centre field 3,480 G; sweep width 100 G; modulation amplitude 1 G; microwave frequency 9.768037 GHz. Researchers also employed APF radical sensing assays and confocal fluorescence imaging with APF (5 mM; Thermo Fisher) diluted to 5 µM using PBS. Models like R-PE (BioLegend) and WGA–Alexa Fluor 647 conjugate (Thermo Fisher Scientific) visualized plastic surface interactions.
Tests on six common plastics—polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, and acrylic—revealed that hydrophobic materials like polyethylene and polypropylene generated the most radicals. Plastics Common in Food Containers and Bottle Caps Did the Most Damage
, a study noted, emphasizing that these materials produced far more reactive species than others. The study also found that smaller plastic fragments, with greater surface area, amplified these reactions.
Health Risks Linked to Microplastic Reactions
The study links microplastic reactivity to biological damage. Mouse red blood cells exposed to polystyrene particles fragmented, and proteins like lysozyme formed aggregates on plastic surfaces. Microplastics change the water that surrounds them, generating high-energy, reactive radicals that likely contribute to biological damage observed in animals and potentially in humans,
Min explained in a Columbia Climate School release.
Microplastics have been found in human tissues, including the brain, with research revealing a 50% increase in brain plastic content compared to 2016. That would mean that our brains today are 99.5% brain and the rest is plastic,
co-lead study author Matthew Campen told CNN. The findings align with growing concerns about microplastics’ role in cardiovascular disease, dementia, and fertility issues.
Researchers observed that microplastics in water triggered oxidative stress and inflammation, which are linked to chronic diseases. We’ve long assumed that plastic itself is inert. Any harm from microplastics, we believed, comes from chemicals added to plastics or pollutants that stick to them,
said Lisa Patel, a physician at Stanford Medicine Children’s Health, in an interview with Everyday Health. The study challenges this assumption, showing that microplastics’ surfaces can independently generate harmful radicals.
Experiments with blood serum and proteins demonstrated that microplastics attracted charged molecules, altering cellular functions. Microplastics hit your lung. They are immediately surrounded by surfactants,
noted Matthew Campen, a professor of pharmaceutical sciences at the University of New Mexico, in an interview. This interaction could exacerbate inflammation and immune dysfunction.
Policy Measures and Research Directions
The federal initiative, announced by the Department of Health and Human Services, aims to create a definitive toolbox for measuring, researching, and affordably removing microplastics and nanoplastics (MNPs) in the human body.
This follows microplastics being added for the first time to the U.S. Environmental Protection Agency’s list of drinking water contaminants of concern.
Researchers plan to test these reactions in living cells and assess how plastic size and type influence toxicity. This challenges the reigning theory that plastic is inert
, and It implies microplastics themselves are a source of oxidative species. Oxidative stress is not a secondary effect of exposure,
noted Wagner. For now, the study offers a chemical explanation for microplastic harm, urging further investigation into its long-term effects.
Public health experts emphasize that while the study identifies a mechanism, it does not confirm harm in humans. It is also important to emphasize that science has not yet established exactly what levels of microplastic exposure cause harm in humans,
said Min. The research underscores the need for stricter regulations and sustainable alternatives, as single-use plastics remain prevalent despite their risks.
President Donald Trump’s advocacy for single-use plastic products, which scientists say release trillions of nanoparticles during use, contrasts with the study’s findings. BACK TO PLASTIC!
he pronounced in an early 2025 Truth Social post, highlighting the tension between policy and scientific consensus. Research reveals a 50% increase in brain plastic content compared to 2016, highlighting the need for further action.