ABSTRACT
Arsenic (As) is regarded as one of the most highly toxic elements of the periodic table (Mondal et al. 2006). It is widely distributed in the earth’s crust and it ranks twentieth in crustal abundance (Mandal and Suzuki 2002). It is ubiquitously present in air, water, groundwater, soil, rock, mineral deposits, and other media in variable concentrations. The frequent detection of As in the environment may be due to the combined effect of natural and anthropogenic processes. The natural processes include weathering of As-bearing rocks, leaching from mineral deposits, especially sulfide deposits such as arsenides, sulfides and sulfosalts, volcanic eruptions, and biological activities, while anthropogenic activities that are responsible for As release comprise the combustion of coal and its by-products, mining and smelting, the use of inorganic and organic arsenic compounds as pesticides, herbicides, and silvicides in various agricultural-and forest-related activities, the manufacturing of plastics, paints, lacquers, and so on. Figure 13.1 depicts various possible sources of arsenic in the environment.
