Chapter 1 - Phytotoxic Properties of Zinc and Cobalt Oxide Nanoparticles in Algaes

Abstract

Excessive use of industrially important nanoparticles increases the chances of their release into the aquatic environment posing harmful effects to aquatic ecosystem. Many studies have suggested the toxic impact of metal oxide nanoparticles in aquatic plants such as microalgae. The present chapter describes the ecotoxicological properties of Zinc oxide and Cobalt oxide nanoparticles towards microalgae. On the basis of early studies and published data it can be suggested that stability of Zinc and Cobalt oxide nanoparticles in aquatic environment and their physicochemical properties such as size, shape, charge etc. greatly influence the toxicity of these nanoparticles. The primary mode of toxicity generation for Zinc oxide and Cobalt oxide nanoparticles across various tested species differ with each other. In case of Zinc Oxide nanoparticles, ionic dissolution and particle-induced generation of reactive oxygen species (ROS) are equally significant mode of action for toxicity while particle-induced generation of reactive oxygen species (ROS) and physical damage to cell membrane are associated toxic mechanism of partially soluble Cobalt oxide nanoparticles. Also, photocatalytic property of Zinc Oxide nanoparticles may be another important mechanism of toxicity. Finally, it has been concluded that current data available in this area of research is limited and more extensive studies are required to acquire proper understanding about the interaction of metal based nanoparticles with aquatic environment.