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A Molecular Window into the Environmental Impacts Of Metals

Department & Center Events
Wolman Seminar

Tuesday, October 3, 2023, 3:00 p.m. - 4:00 p.m. ET
Mergenthaler 111
Past Event

Rene Boiteau, assistant professor in the Department of Chemistry at the University of Minnesota.

After earning an undergraduate degree in chemistry from Northwestern University, he received an MPhil in Earth Sciences from Cambridge University, followed by a PhD in 2016 from the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution. He then went on to a postdoctoral fellowship at PNNL before moving to the College of Earth, Ocean and Atmospheric Sciences at Oregon State University in 2018. He moved to the University of Minnesota in 2023, where his research group develops analytical approaches (especially mass spectrometry) that provide new windows into how elemental cycles are structured at the molecular level. Leveraging these and other 'omics' tools, his goal is to develop predictive knowledge of how metals and organic nutrients impact environmental health, food webs, and evolutionary adaptations.

The fate of micronutrients and toxic metals in the environment is largely governed by organic ligands that bind to metals and affect their solubility, reactivity, and bioavailability. Thus, understanding metal distributions in the environment and assessing their environmental impact requires fundamental knowledge of the sources and chemistry of organic ligands. Determining the composition, metal binding properties, and bioavailability of organic ligands has remained a formidable analytical challenge due to the trace quantities of metals and the complexity of natural organic matter. To address this knowledge gap, our research group develops and employs new approaches for identifying and quantifying the specific organic molecules that strongly bind metals in environmental samples using chromatography and multimodal mass spectrometry.

This presentation will discuss how these techniques have generated molecular-level knowledge of how organic ligands control metals in the environment via two examples. First, iron scarcity limits biological production across one third of the surface ocean. Organic ligands are responsible for solubilizing the iron that reaches these regions, but their sources, composition, and reactivity has remained unknown. By developing scalable analytical approaches to survey organic-iron speciation across the ocean, our research uncovers the processes that supply iron to surface waters, govern its bioavailability to phytoplankton, and ultimately support the growth of marine ecosystems. Second, the pollution of surface waters by heavy metals, particularly copper, in stormwater and wastewater is a global challenge. We are identifying the organic ligands present in these waste streams, aiming to improve metal speciation models used to assess water quality and develop more effective remediation strategies based on knowledge of the chemical forms of metals that must be removed.