Lab- and Field-Scale Studies on the Fate and Transport of Nanoparticles in Streams: Influence of Nanoparticle Characteristics, Macromolecules, and Environmental Parameters

The mass production and wide application of engineered nanoparticles (NPs) increase the possibilities for their unintended or irresponsible release to the environment. Streams are an integral, connecting network in the environment that can transport contaminants long distances. Thus, understanding the fate and transport of NPs in the streams is critical to environmental health and sustainable nanotechnology. Numerous lab-scale studies explored the behavior of NPs in artificial stream water, such as their interaction with various aqueous parameters (e.g., pH, temperature, ionic strength, presence of natural organic matter, mineral ions, or inorganic particles). Nevertheless, lab-scale studies are limited in incorporating all the environmental factors simultaneously, including mimicking seasonal variations (e.g., biofilms) and hydraulic factors (e.g., stream bed size and material), thus there exists a need to better understand the NPs behavior in realistic streams. Furthermore, reliable mathematical models are required to predict the fate and transport of NPs accurately for the feasible management of the environmental risk of NPs and the use of NPs for environmental remediation. The primary research originality of this dissertation were to (1) elucidate the interaction of NPs with environmental macromolecules (e.g., proteins and natural organic matter) under realistic lab-scale conditions, (2) evaluate the effect of physicochemical properties of NPs (hydrodynamic size and zeta potential) and environmental parameters (pH, ionic strength, and ionic species) on the fate of NPs at the lab-scale, (3) monitor the transport of NPs in field-scale streams under hydraulically controlled conditions, (4) evaluate the effect of natural organic matter, biofilms, and streambed substrate size on the transport of NPs in field-scale streams, and (5) develop a one-dimensional stochastic model to predict the transport of NPs in streams. The outcomes of this dissertation suggest (1) more field-scale studies are required for a better understanding of NPs’ behavior in the real environment, and (2) modeling approaches should consider the effect of streambed gravel sizes and biofilms on the transport of NPs in streams. Lastly, the computational modeling outcomes in this study will contribute to predicting the transport of NPs irresponsibly or accidentally released to the stream environment.