Understanding the relation of As and Mn biogeochemistry within Fe-rich sediments in southeast Asian aquifers

摘要

Aquifer sediments were collected from varying depths from selected villages in Murshidabad, India. Hydrological and physico-chemical parameters of groundwater were measured and aquifer cores were collected. Solid phase analysis includes X-Ray Diffraction (XRD), X-ray Absorption Spectroscopy (XAS) and x-ray imaging. Primary focus of this work was to understand the inter-relation of As and Mn biogeochemistry in presence of Fe-rich minerals. Mechanism of As and Mn release is controlled by the oxidation-reduction of Fe bearing minerals in these subsurface aquifers. With our spectroscopy data, we have observed reduced As and Mn species in aquifer sediment as the depth increased relating directly to elevated concentration of As and Mn observed in groundwater. These observations are vital in understanding the inter-depending behavior of As and Mn in subsurface sediments.