This proposal is submitted in response to RFA-ES-10-010, entitled Superfund Hazardous Substance Research and Training Program (P42). The proposed work involves substantial work at the single most serious arsenic (As) Superfund site in Vineland, NJ. It also involves unique epidemiologic studies of As and Manganese (Mn)-exposed adults and adolescents residing in Bangladesh as well as an important mechanistic investigation of As-induced epigenetic dysregulation. As in the past, the Columbia University SRP Center includes a balance between biomedical and non-biomedical research. The proposal includes three biomedical research projects:1) Health Effects of As Longitudinal Study (HEALS); 2) Consequences of As and Mn Exposure on Children's Health; and 3) Impact of Nutrition on Arsenic-Induced Epigenetic Dysregulation. The biomedical research is intimately intertwined with three nonbiomedical projects: 4) Arsenic, Iron, Sulfur and Organic Carbon Speciation, and Their Impact on Groundwater Arsenic; 5) Application of Enhanced Mitigation Methods for Groundwater As at US Superfund Sites; and 6) Defining the Sustainable Uses of Low-As Aquifers in Bangladesh. The Projects are supported by four Research Support Core Laboratories: 8) Data Management; 9) Trace Metals; 10) Biogeochemistry; and 11) Hydrogeology. A Research Translation Core (RTC) entitled, Collaborating with government and the NIEHS SRP Center: As and Mn Exposure in Groundwater works with several government agencies to help understand and solve their local groundwater problems. Finally, the RTC will work closely with the Community Engagement Core (CEC) entitled Promoting As Testing and Treatment to Reduce Health Risks for Residents in Maine. The CEC has developed naturally from our past biomedical and geochemical As research in Maine.