New Study Reveals Microplastics Generate Reactive Free Radicals in Water

For decades, society has relied on plastics largely because of the assumption that the materials remain chemically inert under normal conditions. A new study published Wednesday in the journal Nature completely upends that paradigm. Researchers at Columbia University and other institutions investigated how microplastics behave when broken down into tiny fragments and submerged in water, uncovering a previously overlooked mechanism that could explain how these particles damage biological health.

Microplastics, defined as any plastic piece smaller than five millimeters, are increasingly prevalent in the environment and have been detected in various parts of the human body. While scientists already knew that plastics contain hormone-disrupting chemicals, the new research demonstrates that the physical breakdown of plastic fundamentally changes its chemical activity. As plastic fragments into smaller particles, its exponential increase in surface area allows it to spontaneously generate unstable molecules known as free radicals in the presence of water.

Senior study author Wei Min explained that these high-energy, reactive radicals alter the surrounding water. Given that human bodies are primarily composed of water, and that people frequently ingest microplastics through sources like bottled water, the generation of these unstable molecules likely contributes to biological harm. Researchers suspect that these free radicals may drive the inflammation, immune dysfunction, and metabolic shifts previously linked to microplastic exposure.

While researchers are still working to fully quantify precise health risks and determine how exposure thresholds differ based on where plastics accumulate in the body, the findings provide a vital clue regarding microplastic toxicity. The team hopes this discovery will prompt better methods of plastic production designed to mitigate free radical generation and reduce environmental and human health risks.