Research interests focus on biogeochemical processes in aquatic systems, with a special emphasis on the chemical speciation of metals, and metal-microbes interactions. Our research group is conducting field studies, laboratory experiments, and modeling approaches to investigate the fate of metals in natural waters. Our current activities are centered on the chemical speciation of Zn, Cd, Pb and Cr in freshwater environments (water & sediments), and soils. To investigate the chemical speciation of metals, we are using an analytical multi-method approach relying on electrochemistry, electron microscopy, and X-ray absorption spectroscopy. These complementary techniques allows us respectively to determine the truly dissolved metal fraction as well as the presence, concentrations, and conditional stability constants of dissolved ligands; probe elemental associations at the nano-scale; and establish the coordination and the valence state of the metal using direct methods.