Events & Media


A PhD Dissertation Defense

"Fate, Transport and Implications of Engineered Nanomaterials
in the Terrestrial Environment"

Jon Conway
PhD Candidate
Bren School

Friday, July 17, 2015
9:30 a.m.
Bren Hall 1424

Faculty Advisor: Arturo Keller
Committee Members: Patricia Holden, Susan Mazer

The majority of the current production, use, and disposal of engineered nanomaterials (ENMs) occurs in terrestrial environments, and consequently, terrestrial ecosystems are and will increasingly be some of the largest receptors of ENMs at all stages of their life cycles. In particular, soil is predicted to be one of the major receptors of ENMs due to ENM-contaminated biosolid fertilizer and nanopesticide application to agricultural fields, runoff from landfills or ENM-bearing paints, or atmospheric deposition. Both agricultural and natural systems are at risk to ENM contamination through these release scenarios, which makes it necessary to understand the interactions between ENMs, soils, and soil organisms such as plants in order to predict their impacts in real-world scenarios.

The goal of my research was to uncover some of the underlying mechanisms controlling the following processes under environmentally relevant conditions: how ENMs move through unsaturated soils, the effects ENMs have on key soil properties, the uptake and distribution of ENMs in plants, and how ENMs influence plant growth and physiology. Major findings include that ENMs are highly limited in their ability to travel through natural soils, but that they can cause changes in soil pH and nutrient availability. Additionally, I found that uptake of ENMs in three plant species was primarily controlled by environmental factors that influence plant transpiration rates, and that high concentrations of ENMs had both direct and indirect toxic effects on plants. This research reveals the new information about how ENMs may behave in the real world and highlights several areas of future study.


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