Hydrogeochemical controls on mobilization of arsenic in groundwater of a part of Brahmaputra river floodplain, India

摘要: Abstract Study region Arsenic enriched groundwater regime within low-industrialized Brahmaputra floodplains in Assam, NE India. focus We examined the origin, distribution and processes of As release by investigating salient chemistry subsurface sedimentological characteristics. Besides collection samples from domestic public water supply wells, sediment boreholes were investigated for textural colour linkages. New hydrological insights concentrations above WHO guideline value 10 μg/L present 33 wells previous Indian national drinking standard 50 μg/L 15 wells. The green-olive sediments more likely to yield As-enriched groundwater. supersaturation with respect Fe(II) minerals, such as siderite vivianite, explained poor correlation between dissolved Fe. result reinforced phenomenon reductive dissolution Fe(III) oxyhydroxides releasing This study throws light on mechanisms involved homogenous floodplain terrain makes imprint unambiguous hydrogeological signatures untarnished. Considering absence anthropogenic sources area, conclusions nature causes looked dependable although final contamination at specific sites would be influenced advection–dispersion flow accompanied retardation, ion exchange, surface complexation possible biodegradation.