The problem of arsenic(As)poisoning in the upper deltaic plains of the Ganges-Bhagirathi river system of West Bengal(WB),India,is terrifying. Elevated As(>50 ppb)in well water was observed within a depth range of 10-30 m in older grey terraces of abandoned fluvial channel deposits in the Murshidabad and Malda districts in WB.Both surface and cored(2-20 m)sediment samples from banks of the river Ganges and along a north-south transect of the main tributary Bhagirathi-Hooghly river were The problem of arsenic (As) poisoning in the upper deltaic plains of the Ganges-Bhagirathi river system of West Bengal (WB), India, is terrifying. Elevated As (> 50 ppb) in well water was observed within a depth range of 10 -30 m in older gray terraces of abandoned fluvial channel deposits in the Murshidabad and Malda districts in WB.Both surface and cored (2-20 m) sediment samples from banks of the river Ganges and along a north-south transect of the main tributary Bhagirathi-Hooghly river were