Date of Award

Spring 2026

Document Type

Open Access Dissertation

Department

Chemistry and Biochemistry

First Advisor

John Ferry

Abstract

Microcystins that enter freshwater systems pose a threat to human health therefore their fate and transport throughout the water column have been intensively studied. While sediment has been regarded as an environmental fate for microcystin (MC), less is known about the molecular mechanisms by which microcystin interacts with the sediment and/or the thermodynamic stability of these interactions. While microcystin has a half-life in lake water on the order of weeks, microcystin adsorbed to sediment can be detected hundreds of years later1-2. Microcystin has been desorbed from these sediments with various EDTA solutions, therefore, work is presented to support the hypothesis that microcystins can bind to sediments surfaces through the formation of discrete metal-organic complexes where this interaction may be the source of stability of microcystin on sediments. Evidence is shown for the formation of complexes of MC-LR-Mx+ complexes (where Mx+ refers to transition metal cations) in solutions of the following: Al(III), Ca(II), Cu(II), Fe(II), and Mg(II). Support for the complexation is provided using various instrumental and experimental techniques while the rate and formation constants for MCLR-Fe complexation compared to other environmental fate pathways are also presented to predict the stability and speed of these interactions.

Rights

© 2026, Ashley Marie Womer

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