Bridging lab and field: Tracking environmentally relevant nanoplastics in crops using Py-GC/MS

The increasing presence of nanoplastics (NPs) in terrestrial environments raises concerns about their bioavailability and potential impacts on crops. This study investigates the uptake and translocation of environmentally relevant polystyrene nanoplastics (eNPs-PS) in Hordeum vulgare L. via soil. eNPs-PS were produced from aged polystyrene (PS) foam using a top-down approach and characterized by Nanoparticle Tracking Analysis (NTA) and Scanning Electron Microscopy (SEM), revealing a polydisperse population with a mean size of 179.8 ± 2.8 nm. A novel acetone-assisted Pyrolysis-Gas Chromatography-Mass Spectrometry (Py-GC/MS) technique method was developed for quantifying PS in plant matrices tissues. Barley cultivated in eNPs-PS -contaminated soil (228.9 mg kg⁻¹), and results demonstrated substantial accumulation in roots (97.6 ± 39.4 µg g⁻¹) and limited translocation to shoots (30.1 ± 10.1 µg g⁻¹; translocation factor (TF) = 0.31). These findings provide the first experimental evidence of root uptake and systemic movement of environmentally relevant nanoplastics in plants. The observed restricted translocation highlights a potential shift in risk from food chain contamination to rhizospheric exposure, with possible implications for soil organisms and microbial symbioses. This work underscores the need to include realistic nanoplastics in environmental risk assessments and supports the development of adapted regulatory test protocols.