USGS: Assessing Element Speciation, Bioavailability, and Cycling using Diffusive Gradients in Thin Films (DGT)
Project work & strategy: Our work involves understanding how elements cycle through the environment and determining how chemical speciation affects the availability and toxicity of elements to biota. Specifically, we determine and model critical physical and biogeochemical processes, such as hydrologic transport, precipitation of mineral phases, and adsorption onto particles, that affect the concentration of elements in aquatic systems impacted by mining activities and evaluate chemical speciation using thermodynamic calculations and a new in-situ technique called Diffusive Gradients in Thin Films (DGT) (http://www.dgtresearch.com). Relationships among dissolved element concentrations, speciation, and toxicity are evaluated using the Biotic Ligand Model (http://www.hydroqual.com/wr_blm.html). We accomplish this work through a series of integrated laboratory, field, and modeling studies.