Stabilized Nanoscale Zerovalent Iron Mediated Cadmium Accumulation and Oxidative Damage of Boehmeria nivea (L.) Gaudich Cultivated in Cadmium Contaminated Sediments

Nanoparticles can be absorbed by plants, but their impacts on phytoremediation are not yet well understood. This study was carried out to determine the impacts of starch stabilized nanoscale zerovalent iron (S-nZVI) on the cadmium (Cd) accumulation and the oxidative stress in Boehmeria nivea (L.) Gaudich (ramie). Plants were cultivated in Cd-contaminated sediments amended with S-nZVI at 100, 500, and 1000 mg/kg, respectively. Results showed that S-nZVI promoted Cd accumulation in ramie seedlings. The subcellular distribution result showed that Cd content in cell wall of plants reduced, and its concentration in cell organelle and soluble fractions increased at S-nZVI treatments, indicating the promotion of Cd entering plant cells by S-nZVI. In addition, the 100 mg/kg S-nZVI alleviated the oxidative damage to ramie under Cd-stress, while 500 and 1000 mg/kg S-nZVI inhibited plant growth and aggravated the oxidative damage to plants. These findings demonstrate that nanoparticles at low concentration can improve the efficiency of phytoremediation. This study herein develops a promising novel technique by the combined use of nanotechnology and phytoremediation in the remediation of heavy metal contaminated sites.