Scientists Show What Happens When Microplastics Meet Blood

It may not just be the chemicals in microplastics wreaking havoc on our bodies. A new study finds microplastics are chemically active all on their own. Columbia University researchers report in Nature that tiny plastic particles shed into water can generate reactive oxygen species—high-energy molecules that can damage DNA, proteins, and cell membranes and are linked to cancer, heart disease, and neurological illness, reports the Washington Post. The team found that even pristine microplastics from common materials like polystyrene, polyethylene, and PET triggered this chemistry not just in water, but also in mouse blood, suggesting a direct route to oxidative stress and inflammation in the body, per Smithsonian.

The key is size: as plastics fragment into microplastics, their surface area explodes, amplifying the reactions. "Proteins get damaged. Cells get damaged," study author Wei Min tells NBC News, adding that "our cells are 60 to 70% water, and therefore this effect could be ubiquitous." Because plastics are persistent, scientists warn that these particles could accumulate in people faster than the body's defenses can neutralize their effects. (Meanwhile, the amount of microplastics accumulating in our bodies is up for debate.)