ZnO nanoparticles (NPs) are one of the most widely used and potentially toxic nanomaterials to living organisms. However, studies on ZnO NP toxicity in a soil matrix are limited. In this research, the system alfalfa-bacterium (M. sativa-Sinorhizobium meliloti ) was treated for 30 days with ZnO NP concentrations ranging from 0 (control)-750 mg kg-1. Concurrent exposures of equivalent ionic Zn and bulk material were conducted with ZnCl2 and ZnO bulk. For all forms (Zn species), effects on germination, plant growth, uptake, biotransformation, leaf area index, root and shoot length, and changes in anti- oxidative enzyme activity were compared. Despite of accumulation in plant roots and stems, ZnO NPs generally had less impact than ZnCl2 on measured traits. At 750 mg ZnO NPs kg-1, root length increased and changes in biomass were observed. Significant increase in root and shoot lengths were also observed in case of 500 and 750 mg kg-1 of bulk ZnO, compared to control. Transmission Electron Microscopy analysis of plant tissues following 30-day exposure showed the presence of ZnO particles, signifying that NPs can be taken up in particulate form. The findings provide the insight of risk assessments of NPs and their corresponding ionic and bulk counterpart.

Comparative eco-toxicities of nanoparticulate ZnO, bulk ZnO and ionic zinc (ZnCl<sub>2</sub>) to the alfalfa-<i>Sinorhyzobium melilot</i>i system in soil matrix

246th National Meeting (2013)

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Comparative eco-toxicities of nanoparticulate ZnO, bulk ZnO and ionic zinc (ZnCl2) to the alfalfa-Sinorhyzobium meliloti system in soil matrix

Comparative eco-toxicities of nanoparticulate ZnO, bulk ZnO and ionic zinc (ZnCl₂) to the alfalfa-Sinorhyzobium meliloti system in soil matrix