Overview
- A paper published in Nature in October 2026 reports that microplastics and nanoplastics in water spontaneously generate reactive oxygen species (ROS) at their plastic–water interfaces.
- The team combined laboratory experiments, spectroscopy, microscopy and molecular simulations to show that water layers next to hydrophobic plastic lower the energy needed for hydroxide ions to form hydroxyl radicals.
- ROS production varied by polymer and surface condition, with very water‑repellent plastics such as polyethylene and polypropylene producing stronger signals than PET or PMMA and surfactant coatings reducing the activity.
- In lab assays the interfacial radicals were linked to biomolecular effects, including protein aggregation and hemolysis of mouse red blood cells, but the authors stress most tests used fresh lab particles and do not prove disease in humans.
- Researchers say the work reframes microplastics as chemically active, calls for in vivo exposure quantification and toxicity studies, and suggests engineering or regulatory paths to redesign or limit reactive plastics.