Arizona Geological Society: From rocks to stalks – Interpreting the controls on biogeochemical signatures and the applications of trace metals

Geologically-sourced metals are a bit of a double-edged sword: they are fundamental to the US economy, from extraction to processing to manufacturing, with future dependence estimated to increase nearly exponentially as we continue our green energy transition. Yet they can also pose serious environmental and human health threats, either when found at higher concentrations or with chronic, long-term exposure. This duality is even more pronounced for metals that can be easily transferred from geologic materials into nearby plant biomass, where they can accumulate in very high concentrations. Here, plant accumulators of metals can be employed as prospecting tools, be utilized as a passive monitoring system for changes in metal sourcing, or function as a vector of metal exposure in nearby communities.

In this talk, I will present new plant-based metal data in an attempt to better model and predict heavy metal (re)distribution near Earth’s surface and explore the potential applications, and limitations, of plant-based metal signatures for exploration and environmental planning. In particular, results from greenhouse studies with Brassica species grown in artificially contaminated soils will be highlighted for two unique metal systems of interest.

Presented by Dr. Shelby Rader, Department of Earth and Atmospheric Sciences, University of Indiana

Dr. Shelby Rader is a geochemist whose research focuses on the redistribution and isotopic fractionation of trace metals through both geological and biological processes, with particular emphasis on how both reservoirs may influence the other and the potential applications therein. Shelby’s research group combines greenhouse studies, field work, and high-precision laboratory measurements to elucidate how metals move through the geosphere and how those geologic signatures may be reflected in biomass once metals are transferred into plant material, with potential applications in biogeoprospecting, remediation, and phytoextraction.

Shelby joined the Department of Earth and Atmospheric Sciences at Indiana University as an assistant professor and Director of the Stable Isotope Research Facility (SIRF) and Metal Isotopes Laboratory (MIL) in 2022. Prior to her time at IU, Shelby completed her PhD at the University of Arizona before serving as a postdoctoral researcher at the University of Massachusetts Lowell.