| As nanomaterial production and use increases, the introduction of engineered nanoparticles (eNPs) into the environment becomes inevitable. The small size, large surface-to-volume ratio and unique properties appearing as particle size decreases has raised concern that the release of eNPs into the environment may adversely impact humans and other species. Once released into the environment, engineered nanoparticles (eNPs) are expected to be subject to processes that may alter their physical or chemical properties, potentially leading to changes in toxicity. These processes may be collectively termed "weathering".;We used the zebrafish (Danio rerio) embryo as a model organism to study the toxicity of intact and weathered engineered nanoparticles (i.e. quantum dots and palladium). Because many developmental processes are conserved across vertebrates, results obtained in the zebrafish have implications for humans as well as for wild fish populations.;In this dissertation, the toxicity of eNPs, both intact and weathered, was explored. At the time this work began, the field of nanotoxicology, especially regarding environmental impacts, was in its infancy. The collection of works described in this thesis have shown that (1) surface functionalization of eNPs impacts toxicity as well as stability under biological and environmental conditions; (2) weathering, under environmentally relevant conditions, can alter the toxicity of eNPs; and (3) toxicity of eNPs is a combination of nanoparticulate material, dissolved ions and ligands. |
