Inorganic arsenic compounds, which are found throughout the environment, can cause acute and chronic toxic effects and arsenic has now been recognized as a human carcinogen. Current uses of arsenic compounds are in the glass industry as a clarifier, as a wood preservative (copper arsenite), in the production of semiconductor (gallium arsenide) as a desiccant and defoliant in agriculture, and as a byproduct of the smelting of non-ferrous metals, particularly gold and copper. Human may encounter arsenic in water from wells drilled into arsenic rich ground strata or in water contaminated by industrial or agro chemical waste (Moncure et al., 1992). Exposure via drinking water has been associated with cancer of the skin and various internal organs as well as hyperkeratosis, pigmentation changes and effects on the circulatory and nervous system. Chronic arsenic toxicity due to drinking of arsenic contaminated water has been reported from many countries. Recently, large populations in West Bengal in India and Bangladesh have reported to be affected with arsenic (Smith et al., 2000, Guha Mazumder et al. 1998, Chowdhury et al., 2000). Exposure to arsenic via drinking water is correlated with a significantly elevated risk of skin and bladder cancer (Rossman, 1998; Moore et al., 2002). About 60-90% of soluble arsenic compounds are absorbed from the gastro intestinal tract following ingestion; inhalation exposure may be similar (ATSDR 1990). Absorption through intact skin is negligible. Absorbed pentavalent arsenic is converted to more toxic and carcinogenic trivalent form (Bertolero et al., 1987; Hall, 2002).
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