ABSTRACT
Arsenic contamination in soils occurs widely in a range of ecosystems resulting from geological origins and anthropogenic activities. On average, arsenic concentration ranges from 5 to 10 mg kg−1 in uncontaminated soils and above 10 mg kg−1 in contaminated soils (Hossain, 2006). Increased buildup of arsenic in irrigated soils has been widely recognized in South and South-east Asia (Brammer and Ravenscroft, 2009), posing significant threats to agriculture sustainability. In Bangladesh, long-term irrigation with arsenic-rich groundwater from shallow aquifers in dry season adds >1000 tons of arsenic to the agricultural soils (Ali et al., 2003). In addition, arsenic contamination in soils results from various anthropogenic activities, such as mining and smelting (Williams et al., 2009), and using arsenic-containing wood preservatives (Chirenje et al., 2003), pigment, pesticides, herbicide (Sarkar et al., 2005) and feed additives (Arai et al., 2003).
