Single and combined exposure of broad bean (Vicia faba) to PFOS and environmental microplastics: Effect at the morphological, metabolomics and PFOS uptake levels

Microplastics (MPs) and perfluorooctane sulfonic acid (PFOS) are emerging pollutants that can co-occur in agricultural soils, but their combined impacts on crops are not yet fully understood. We investigated early-stage responses of broad bean (Vicia faba) grown for 28 days in greenhouse soil exposed to environmental MPs (50 mg kg⁻¹), PFOS (10 or 100 µg kg⁻¹), and their combinations. Targeted high-resolution mass spectrometry analyses quantified PFOS in plant tissues and glutathione redox status (GSH/GSSG), whereas untargeted metabolomics investigated global biochemical changes. Individually, MPs and PFOS reduced shoot length (29-33 % vs control). Conversely, biomass increased under co-exposure, indicating a distinct physiological adjustment. Noteworthy, PFOS accumulated dose-dependently and was enhanced by MPs (up to 6.92 ng g⁻¹ FW in shoots and 263.36 ng g⁻¹ FW in roots), evidencing MP-mediated modulation of PFOS bioavailability. Redox balance shifted toward oxidation: GSH/GSSG declined across treatments, especially in roots at high PFOS (-60 %). Metabolomics, followed by multivariate statistical analysis, successfully separated the control from the treated plants, with AMOPLS apportioning variance primarily to PFOS and the PFOS×MPs interaction. Discriminant metabolites in shoots highlighted a dose-related accumulation of isoprenoid and fatty-acid biosynthesis, stronger under MPs+high PFOS, while roots exhibited suppressed isoprenoids and enhanced phenylpropanoids at high co-exposure. Our results highlighted an MPs-PFOS interaction at the metabolome level, identifying MPs as dynamic modulators of PFOS uptake. Co-exposure elicits an emergent stress signature involving redox imbalance and a tissue-specific secondary metabolism allocation. Our data should be carefully considered concerning environmental PFOS contamination in the context of environmental microplastics.