My primary research interests are in aqueous geochemistry applied to natural waters, including rivers, lakes, groundwater, and geothermal waters. I am particularly interested in the geochemistry of heavy metals and metalloids (As, Sb), the processes that form economic deposits of these metals, and the processes that disperse these metals in the weathering environment. Much of my recent research involves the application of stable isotopes of water, dissolved oxygen, inorganic carbon, and sulfur.