Many water supplies worldwide are affected by arsenic at concentrations above acceptable health levels. This hazard has motivated research directed at understanding the occurrence, distribution, and mobilization of arsenic in the environment. The papers collected in this volume bring together arsenic-related research from a diversity of areas, including geological, geochemical, hydrological, microbiological, ecological, and engineering aspects, with particular
emphasis on the integration of basic research into mitigation and remediation strategies.