Natural Colloids and Manufactured Nanoparticles in Aquatic and Terrestrial Systems

Abstract

The role of natural colloids in the biogeochemical cycle, speciation, fate, transport, and bioavailability of trace pollutants such as trace metals has long been recognized, and this has fueled interest with regard to natural colloids in environmental systems. Nonetheless, the study of such a dynamic system has proved to be complex. A new layer of complexity is being added recently with the discovery of nanotechnology, resulting in the release of nanoparticles (NPs) to environmental systems. The NPs used in nanotechnology have similar behaviors to natural colloids, but can be considered as an additional pollutant and may be bioavailable and toxic to environmental organisms themselves. This chapter discusses definitions of both natural colloids and manufactured NPs, and the overlap between them. The major types of both natural colloids and manufactured NPs, as well as the intrinsic properties of each of them are discussed in detail. Fate and behavior of natural colloids are considered, followed by a discussion of the potential fate and behavior of manufactured NPs in the environment and the lessons learned from the literature on natural colloids. Finally, a list of recommendations and issues to be addressed in future research is highlighted. Given the broad audience of this book, this chapter aims to provide a comprehensive overview of these two overlapping areas with the purpose of highlighting the important issues that can be learned from natural colloidal science and applied to NPs in the environment and vice versa. Review articles have been cited for many of the areas discussed so that more in-depth information can be sought in specific areas.