Melody S. Nocon

Graduate Student

Research Interests

Groundwater Geochemistry of Arsenic

Research Description

I am interested in the abiotic groundwater geochemistry of arsenic in altered local aquifer environments. Aquifers are comprised of saturated geologic units whose chemical mineralogy represents complex assemblages of dominant and trace solid phases. In natural aquifer systems where the approach to chemical equilibrium has been established over long geologic time scales, it is likely that the chemical composition of groundwater is primarily tied to the mineralogy of the aquifer. In altered aquifer systems, such as in the case with groundwater recharge via injection wells, the abrupt introduction of a foreign aqueous chemistry is likely to change both the groundwater and mineralogical composition of the aquifer through a series of geochemical processes including mineral dissolution, precipitation, adsorption, and transformation. My research is targeted on understanding the chemical mobility and stability of inorganic aqueous arsenic in such an environment. More specifically, I seek to understand the geochemical role of: (1) trace iron sulfide minerals as sources for aqueous arsenic, (2) redox sensitive mineral oxides as adsorptive sinks, and (3) common ions that can interfere with the sequestration of aqueous arsenic by a solid phase.