Microbubble-induced erosion releases micro- and nanoplastics into water

Micro- and nanoplastics (MNPs) are pervasive micropollutants in aquatic environments and along shorelines. Their release is predominantly attributed to mechanical abrasion or ultraviolet exposure, both requiring substantial external energy inputs. The role of aquatic factors (e.g., air bubbles) in the generation of MNPs is poorly understood. Here we show microbubbles that spontaneously form on seven typical plastics across a wide temperature range (25° to 95°C) and in various water types (deionized, tap, river, and marine water) can erode plastic surfaces and drive MNP release. Nucleation, expansion, and movement of microbubbles generate shear stresses capable of dislodging polymer protrusions at surface defect sites. This sweeping action, combined with the unbalanced surface tension forces at the three-phase contact line, generates O-shaped ring structures composed of accumulated polymers, which ultimately fragment leading to the release of MNPs into the aquatic environment. Our findings demonstrate that microbubble-induced erosion represents a low-energy pathway for micropollutant release.