My research aims to link environmental geochemistry and isotope hydrology in order to trace the sources and mechanisms of water contamination and relationships with human health. Current research includes global changes of the chemical and isotopic compositions of water resources due to human intervention and contamination, salinization of water resources in the Middle East and Northern Africa, naturally occurring contaminants (arsenic, fluoride, boron) and radioactivity in water resources, the impact of coal combustion residues on the environment, and the impact of gas drilling and hydro-fracking on the quality of shallow groundwater.