Abstracts

Numerous studies have shown that some nanomaterials are highly toxic to aquatic organisms and can potentially disrupt overall community health; however, current methods to evaluate the nanomaterials environmental impacts rarely consider the environmental realism or provide sufficient detail on the impact at the community level. Here we demonstrate three approaches that can effectively evaluate the environmental impacts of nanoparticle (NP) exposure: a chronic trophic food chain exposure, a rapid and cost-effective multi-species community exposure, and an end-of-life toxicity evaluation. The research comprising this dissertation primarily focuses on metal-based nanomaterials of varying size, surface functionalization, oxidation states, solubility, and aggregation behavior, and assesses the impacts of these variations on dissolution, uptake, and environmental toxicity. The chronic trophic food chain exposure demonstrates that NPs can transfer through the food chain and cause long-term toxicity to aquatic organisms, and additionally, elicits differential toxicity relative to directwaterborne exposure. In the multi-species community exposure, dissolved metal ions contribute a large fraction of toxicity to the environment. However, NPs can also elicit particle-specific uptake and toxicity depending on the particle type, and surface functionalization can dramatically modify NP fate and toxicity. Finally, an end-of-life toxicity evaluation on monoalkyltin cluster coated thin film wafers was performed. The low toxicity suggests our synthesized tin clusters and the tin films can be environmentally benign materials suitable for large-scale use in the semiconductor industry. Most important, the multi-species community approach utilized in this dissertation demonstrates benefits, such as high repeatability, rapid execution and cost-effectiveness relative to other standardized methods. Due to these benefits, this assay could be established as a new standardized method to evaluate the environmental impacts of nanomaterials and enhance our ability to rapidly screen the toxicity of nanomaterials and understand their impacts at the community level. The comprehensive understanding gained throughout this dissertation provides the basis for nanomaterial environmental impact evaluation and risk management for sustainable nanotechnology development.Advisors/Committee Members: Harper, Stacey L. (advisor), Radniecki, Tyler (committee member).