Co-exposure of silver nanoparticles and chiral herbicide imazethapyr to Arabidopsis thaliana: Enantioselective effects.

Abstract

In this study, we investigated the possible combined exposure effects of silver nanoparticles (Ag-NPs) and chiral herbicide imazethapyr (IM) on Arabidopsis thaliana. Herein, we show that co-exposure of Ag-NPs and chiral herbicide IM to A. thaliana can amplify the enantioselective ecotoxicity. It was found that after co-exposure of the herbicidally active 0.2 μM (R)-IM and 100 μM Ag-NPs, the silver concentration in roots was 1.40-fold higher than the co-exposure of Ag-NPs and (S)-enantiomer, as well as occurring in shoots that Ag-NPs combined with (R)-IM increased the Ag(+) concentration 77.78% than that with (S)-IM, suggesting an (R)-enantiomer preferential silver uptake. Increase of Ag(+) release under co-exposure of Ag-NPs and (R)-enantiomer was also observed. Our experiments indicated that under co-exposure of Ag-NPs and (R)-enantiomers, more accumulated amino acids can form more adducts with Ag(+), resulting in more Ag(+) release from Ag-NPs and higher ecotoxicity.