Environmental and Colloidal Behavior of Engineered Nanoparticles

Abstract

Engineered nanoparticles (ENPs) are increasingly used in various industries and can be readily found in the products surrounding our everyday life. They are increasingly attracting attention from scientists, government regulators, and the public due to the concern over their potential toxicity and harms. Because of the widespread use of ENPs, they are most likely to release into the environment; however, scientific understanding on their environmental fate and behavior is very limited. Therefore, environmental and colloidal behaviors of carbon nanotubes (CNTs), fullerene, and oxide nanoparticles were examined using various spectroscopic and microscopic techniques. CNTs could greatly adsorb organic contaminants including PAHs and endocrine disrupting compounds, which may affect the toxicity and fate of both CNTs and organic contaminants in the environment. Adsorption mechanisms are also discussed. Dissolved organic matter (DOM) is able to adsorb on both CNTs and oxide ENPs, thus could increase their dispersion and suspension stability. Preliminary data demonstrate that oxide ENPs are more toxic than their bulk counterparts to nematode (C. elegans) and three bacteria species. Also, ZnO ENPs could inhibit plant growth and may be taken up by plant. This work highlights the importance of a better understanding of environmental impact of ENPs and calls for safe design, development, and use of nanoparticles.