8. Arsenic Distribution and Mobilization: A Case Study of Three Districts of Uttar Pradesh and Bihar (India)

Tectonic evolution of Himalayas is related to high erosional potential and substantial sediment transport. Fluvial deposition of clastic material in the Middle Gangetic plain (MGP) is mainly governed by crustal deformation and climatic condition of Himalayas (Singh M, Singh IB, Müller G, Geomorphology 86:144–175, 2007). Seven large Asian rivers—Ganga, Indus, Brahmaputra, Yangtze, Huang He or Yellow River, Salween and Mekong—are fed by Himalayan glaciers which are supplying ~30 % of the global sediments to the ocean (Milliman JD, Meade RH, J Geol 9:1–19, 1983; Singh VB, Ramanathan AL, Pottakkal JG, Kumar M, J Asian Earth Sci 79:224–234, 2014, 2005). High flux of sediment transported from different terrain of Himalayas is product of geologically young rock formation (Singh VB, Ramanathan AL, Pottakkal JG, Kumar M, J Asian Earth Sci 79:224–234, 2014). It provides an opportunity to study the fluvial system and post-depositional changes in sediment water interaction depending on the degree of mobility of element under the altered environmental conditions. Arsenic (As) contamination of groundwater is a global problem. Understanding of As mobilization from sediments to As-contaminated aquifers is important for water quality management in areas of MGP of India.