Migration of silver nanoparticles in an aquatic systemwith Eichhornia crassipes

The migration and dissolution of AgNPs in an aquatic system with plants was investigated. By using a hydroponic system with Eichhornia crassipes, the absorption and transportation processes of silver nanoparticles were investigated. The results show that AgNPs concentrations in the water phase declined with the increase in time, and the reduction degree was dependent on the initial concentrations of AgNPs. The silver concentrations in the roots(r=0.98, p<0.05), stems and leaves(r=1, p<0.001)were significantly positively correlated with the initial concentrations of AgNPs. Silver nanoparticles accumulated in plant roots more than stems and leaves. Compared with the addition of AgNO3 at identical concentrations, lower removal rates of silver and plant uptake were observed in the AgNPs stress systems. A significant positive correlation was also found between the initial AgNPs concentrations and the removed amount of silver(r=0.99, p<0.001). For AgNPs, the primary removal mechanisms in these aquatic systems were agglomeration and sedimentation, while the absorption by plants had a relatively weak contribution.