The Impact of Aquifer Flushing on Groundwater Arsenic Across a 35-km Transect Perpendicular to the Upper Brahmaputra River in Assam, India.

ABSTRACT: Well testing in the floodplain of the Brahmaputra River in Golaghat and Jorhat districts of Assam, India, shows that groundwater arsenic (As) concentrations increase with distance from the river. To establish the origin of this pattern, an additional 900 wells <60 m deep were tested for As and 9 sites were drilled along a 35-km transect perpendicular to the river. The field data show no relation between groundwater As concentrations ranging from <1 to 660 μg/L along the transect and (a) As concentrations of <1-5 mg/kg in cuttings of aquifer sand recovered while drilling or (b) the degree of reduction of iron oxides in these cuttings. The drilling indicates, however, a marked increase in the thickness of a clay layer capping the aquifer starting from <1-5 m near the river to over 60 m at th

SUBMITTER: Choudhury R 

PROVIDER: S-EPMC6424526 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature