ARSENIC CONTAMINATION: SOURCES, EXTENT AND IMPACT ON THE ENVIRONMENTC.A. PHILIP AND V. CHHABRA
Arsenic (As) is a heavy metalloid with emanating concern of its environmental toxicology worldwide. Arsenic is released into the living environment via natural and anthropogenic sources. Natural phenomena include dust storms, forest fires, volcanic eruptions, hydrothermal activities, pedogenesis and geothermal activities. Agricultural inputs like chemical fertilizers and pesticides, dumping of municipal wastes, addition of untreated effluents resulting form industrial activities into the surroundings, smelting, mining, cement manufacturing, coal burning and disarmament of the chemical weapons are considered as human activities. The potential threat of Arsenic is extended over 105 nations and 226 million populations on a global scale. As contamination in soil and groundwater is the major route for human exposure. Many parts of the world have been reported As levels exceeding the threshold limits for soil as well as groundwater. The chemical similarity of arsenate and phosphate facilitate the entry of As into plants and disrupt the metabolic and physiological pathways. Apart from its carcinogenic risk, chronic exposure leads to arsenicosis and other disorders. Phytoremediation and microbial remediation are environmental friendly and cost effective technique for As removal and nanotechnology is an emerging technology with wide application in removal of metal pollutants from the contaminated site.