Mineralogical and geochemical properties of arsenic-contaminated aquifer sediments, Datong Basin, North China

摘要

The contents of As, Fe, Mn, S and inorganic and organic carbon as well as the grain sizes of the sediments from both high and low arsenic aquifers at Datong Basin were analyzed. The vertical distribution of As in the sediments and the weak correlation of As with Fe and Mn indicate that the bulk contents of Fe and Mn are not major controlling factors. However, there exist positive correlations between extractable iron, manganese and arsenic, indicating that the iron and manganese oxyhydroxdies could be the main source of arsenic. Desorption or reductive dissolution of arsenic from iron/manganese oxyhydroxides and subsequent arsenic release into the aquifer maybe the major mechanism of high arsenic groundwater occurrence at Datong.