Polystyrene micro and nanoplastics attenuated the bioavailability and toxic effects of Perfluorooctane sulfonate (PFOS) on soybean (Glycine max) sprouts.

Microplastics and nanoplastics (MNPs) have attracted much attention since their wide distribution in the environment and organisms. MNPs in the environment adsorb other organic pollutants, such as Perfluorooctane sulfonate (PFOS), and cause combined effects. However, the impact of MNPs and PFOS in agricultural hydroponic systems is unclear. This study investigated the combined effects of polystyrene (PS) MNPs and PFOS on soybean (Glycine max) sprouts, which are common hydroponic vegetable. Results demonstrated that the adsorption of PFOS on PS particles transformed free PFOS into adsorbed state and reduced its bioavailability and potential migration, thus attenuating acute toxic effects such as oxidative stress. TEM and Laser confocal microscope images showed that PS nanoparticles uptake in sprout tissue was enhanced by the adsorption of PFOS which is because of changes of the particle surface properties. Transcriptome analysis showed that PS and PFOS exposure promoted soybean sprouts to adapt to environmental stress and MARK pathway might play an important role in recognition of microplastics coated by PFOS and response to enhancing plant resistance. This study provided the first evaluation about the effect of adsorption between PS particles and PFOS on their phytotoxicity and bioavailability, in order to provide new ideas for risk assessment.