ENVR 55 |
| Phytotoxicity of ZnO nanoparticle (nano-ZnO) to Lolium perenne (ryegrass) was investigated. Ryegrass biomass was significantly reduced with increasing nano-ZnO in nutrient solution. Zn2+ concentrations in the nano-ZnO (10-1,000 mg/L) treated nutrient solution were lower than 6 mg/L, indicating that the phytotoxicity of nano-ZnO could not come from its dissolution in the solution. Both treatments of nano-ZnO and Zn2+ increased Zn content of ryegrass, but with different trends. SEM observation showed that nano-ZnO coverage on the root surface increased with increasing nano-ZnO concentration. However, shoot Zn contents (0.25-1.36 mg/kg) remained low under the nano-ZnO treatments and were much lower than that under the Zn2+ treatments (0.25-19.1 mg/kg). This indicates that nano-ZnO might not transport from root to shoot or dissolve to be Zn2+ at root surface or inside root tissue in this study. Phytotoxicity of nano-ZnO may result from physical and chemical interferences of root growth by nano-ZnO, rather than its dissolution. |
|
Environmental Behavior and Fate of Manufactured Nanomaterials
8:30 AM-12:10 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. 235, Oral
Division of Environmental Chemistry |