Arsenic

Arsenic is a ubiquitous element that ranks 20th in abundance in earth's crust. It is distributed throughout minerals, rocks, soil, sediment, water, air, living organisms and marine environment. Exposure to arsenic may come from natural source, industrial source, or administered acute poisoning. Arsenic is mobilized through a combination of natural processes such as weathering reactions, biological activity and volcanic emissions as well as through anthropogenic activities. Inorganic arsenic species have been considered as human carcinogens. Considerable concern exists globally about arsenic in potable/drinking waters extracted from contaminated aquifers. World's two biggest cases of groundwater arsenic episode have been reported in Bangladesh and West Bengal, India. Several biological media have been used to assess arsenic exposure in humans. The key analytical figures of merit for quantification of arsenic are high sensitivity with low detection limits and high selectivity to reject interfering species. Removal of arsenic has been attempted using several techniques including coagulation and filtration,adsorption, ion exchange, bioremediation and membrane separation technologies.