Events & Media


A PhD Dissertation Defense

"Influence of Microorganisms and Extracellular Polymeric Substances on
the Fate of Engineered Nanomaterials in Natural Aquatic Systems"

Adeyemi Adeleye
PhD Candidate
Bren School

Thursday, May 28, 2015
3:15 p.m.
Marine Science Institute Auditorium (1302)

Faculty Advisor: Arturo Keller
Committee Members: Patricia Holden, Hunter Lenihan

Although the risks that engineered nanomaterials (ENMs) pose to humans and the environment are poorly understood, more than 1,700 consumer products currently on the market contain at least one ENM. The use of many of these products will lead to direct release of ENMs into natural waters, where they may have adverse ecological effects. It is therefore important to understand the fate of ENMs in natural waters in order to predict and/or investigate their environmental implications. Studies on how microorganisms and their exudates, such as soluble extracellular polymeric substance (sEPS), influence the fate and transformations of ENMs in natural waters are rare. In this doctoral research, sEPS were extracted from freshwater and marine algae, and their effects on the environmental fate of a variety of ENMs were studied. Interactions between algae, sEPS, and ENMs, and the implications of such interactions were investigated using various macroscopic and molecular analytical techniques. Evidences for direct interactions between algae/sEPS and ENMs were found and adsorption of sEPS to ENMs modified the physicochemical properties of the particles. Effect of sEPS and algae on particle stability, transformation, and toxicity were also observed.


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