Fixation Effect of Fe3O4-GO to Hinder Pb(II) Translocation into Leek

Agricultural soil is easily polluted by heavy metal and recently by metal-based nanoparticles, which has been synthesized in lab and discarded to environment. The uptake and accumulation of them by crops in polluted soil may pose high risks for human health. Here, we investigated the fate and the fixation effect of Fe3O4-GO nanocomposites (NCs) to lead ions in the soil-leek system during four harvest lifecycle. The results showed within 100 days, 600-mg/kg Fe3O4-GO significantly decreased Pb(II) concentrations in leaves by 37.89%, 39.10%, 73.86%, and 47.17% compared with controls. When Fe3O4-GO was added into Pb(II)-polluted soil, a significant fixation effect of Pb(II) was found, and the reduce percentages were 47.29%, 66.60%, 78.04%, and 39.16% for leaves, stem, storage roots, and absorbing roots compared with controls. The scanning electron microscope images showed that the overall appearance of Fe3O4-GO has not been destroyed during the interaction with soil.