Date of Award


Document Type


Degree Name

Master of Science


Department of Systems Engineering and Management

First Advisor

Michael L. Shelley, PhD


Phytoextraction is a remediation technology that uses plants to remove heavy metals from soil. This technology has the potential to decrease the costs of remediating contaminated sites by several orders of magnitude compared to traditional technologies. To effectively implement this technology requires an understanding of the plant processes that control uptake and translocation of metals from the soil. Currently these processes are poorly understood, and especially so for Pb. The purpose of this thesis was to gain insights concerning the plant mechanisms that control uptake and translocation of Pb and how these mechanisms interact to control levels of Pb accumulation in the plant. This was accomplished by developing, testing, and implementing a system dynamics model that simulated a maize plant taking up and translocating Pb. As a result of a rigorous process of conceptualization, formulation, and testing, it appears that this model is a valid tool for studying uptake, translocation, and accumulation of Pb. The results suggest that precipitation of Pb as a Pb-phosphate at the root surface and throughout the plant is one of the most important mechanisms in this system. The maximal uptake rate of Pb (Vmax) and effective root mass may also be key plant parameters in this process. The model may also be used to test various phytoextraction management scenarios, two of which were tested in this study.

AFIT Designator


DTIC Accession Number