AbstractsBiology & Animal Science

Nanotechnology is an emerging field with applications across many industries. Carbon-based nanomaterials (CNMs) such as multi-wall carbon nanotubes (MWCNTs), graphene (G), and graphene oxide (GO) are engineered nanomaterials used in environmental, medical, technological, and agricultural applications. Some of these practices include direct application to the terrestrial and aquatic environment, which can pose risk to environmental and human health. Studies have shown potential for accumulation and toxicity in aquatic organisms when exposed to CNMs. Furthermore, it is uncertain how CNMs interact with contaminants in the aquatic environment as CNM concentration, colloidal stability, and size effect bioavailability and fate in the environment. Research from this dissertation will investigate adsorption, bioaccumulation, toxicity, and trophic transfer of CNMs in the aquatic environment. Adsorption of Cu2+ ions onto MWCNTs, G, and sodium dodecylbenzene sulfonate (SDBS) was measured in moderately hard or hard freshwater. Higher adsorption capacities were seen in CNMs in moderately hard freshwater. In solutions of high ionic strength CNM adsorption capacities decreased. Bioaccumulation was seen in D. magna exposed to MWCNTs of varying outer diameters (O.D., 8-15 nm or 20-30 nm) in moderately hard or hard freshwater using a microwave-induced heating method. Highest MWCNT concentrations were seen in D. magna exposed in hard freshwater, however there was no significant difference between O.D. sizes in bioaccumulation. Generation of reactive oxygen species (ROS) was observed in D. magna exposed to CNMs in moderately hard freshwater after 12 h and an overall decrease in swimming velocity was seen in all CNM treatments. Trophic transfer was observed between D. magna and Pimephales promelas (fathead minnow, FHM) exposed to MWCNTs with varying O.D.s without and in the presence of Cu2+ ions. MWCNT concentrations were quantified using a microwave-induced heating method. Trophic transfer was observed for both MWCNT sizes. Higher concentrations of MWCNTs (20-30 nm O.D.) were seen in FHM in the presence of Cu2+ ions. A similar trend was seen in Cu2+ ions accumulated in FHM, indicating complexation or adsorption of Cu2+ onto MWCNTs. This research will aid in ecological risk assessment and future nanomaterial regulation. Advisors/Committee Members: Cañas-Carrell, Jaclyn E (advisor), Green, Micah J (committee member), Klein, David M (committee member), Maul, Jonathan D (committee member), Saed, Mohammad (committee member).