Oligomer self-assembly is a major source of nanoplastic release from household plastic cutting boards

Plastic cutting boards are ubiquitous in household food preparation, yet whether routine chopping generates nanoscale plastic particles primarily by polymer fragmentation or by oligomer self-assembly remains unresolved. Here, using an integrated workflow that combines controlled chopping experiments, multimodal particle characterization, ethanol partitioning, pyrolysis–GC–MS/HPLC-CAD, molecular dynamics simulations, zebrafish assays, and scenario-based exposure modeling, we show that household plastic cutting boards are a substantial source of both microplastics and oligomer-derived nanoplastics. Across seven commercial boards, a 10-min chopping session (600 strikes) released 2750–7242 microplastics (62–164 μm) and 2.33 × 10⁷–1.12 × 10⁸ nanoparticles (104–200 nm). One month of photoaging increased nanoparticle release by up to 963% and shifted particle sizes below 50 nm in the tested representative PP board. Chemical analyses indicated that 38.2–55.0% of nanoparticles from new boards were oligomer-derived, rising to 92.7% after aging in the representative board. Molecular simulations showed that polypropylene oligomers self-assemble into spherical aggregates, whereas polyethylene oligomers preferentially form layered structures. Integrating experimentally measured release functions with regional cooking statistics for 144 regions from 2019 to 2022, we identified a behavior-driven exposure maximum in 2021. These findings identify oligomer self-assembly as a previously overlooked mechanism of nanoplastic generation during controlled cutting-board abrasion. Plastic cutting boards, common in kitchens, are known to release nanoparticles under continuous use, yet it is not established whether nanoplastics are generated by polymer fragmentation or oligomer self-assembly. Here, the authors demonstrate that chopping on plastic boards releases significant amounts of microplastics and oligomer-derived nanoplastics, with aging increasing the nanoparticle share and reducing particle sizes, highlighting oligomer self-assembly as a key mechanism with implications for human exposure.