6 - Comparative Impact Assessment of TiO2 and ZnO Nanoparticles to Rocket (Eruca sativa L) Plant

Abstract

Concerns about the environmental risks of engineered nanomaterials (ENMs) have been growing in parallel to nanotechnology development, however, their effect on different species in the environment deserve further studies, in particular, terrestrial plants as ENMs accumulate in the biosolids of urban wastewater treatment plants. There has been only one study investigating the effect of Zn on Roket plant (Eruca sativa L.). In this work, the fate of TiO2 and ZnO ENMs that have a vast range of use among nanoparticules was evaluated for ecotoxicity to Rocket plant. Ti and Zn were mixed in the soil at varying doses (50, 100, 200, 400, 600ppm) before seed germination application. When the plants were grown enough in the pots only three plants were left to grow during 60 days, after that they were harvested to submit to many qualitative and quantitave analyses, such as length and diameter of the plant (cm), length of leaf (cm), diameter of leaf (cm), root length (cm), weight of the plant (g) and number of leaves to understand the mechanism of the toxicity. Harvested Rocket plants were washed with distilled water, than, were dried for 48 hours at 68°C to define dry weights before microwave assisted extraction for metal analysis using ICP-OES. Soil samples were submitted to soil structure and metal analysis too. Initial doses of both TiO2 and ZnO were found to affect at 5% the uptake of the metals by Rocket plant. The low level bioavailability of metals was attributed to the soil structure.