Comparative Analysis of Arsenic Speciation in Sediments of the Diaojiang River Using X-Ray Absorption Near Edge Structure Spectra and Sequential Chemical Extraction

Sequential chemical extraction method and X-Ray absorption near edge structure(XANES) spectra were used to investigate arsenic speciation in sediments of the Diaojiang River and tailings from a pollution source area.XANES spectra showed that arsenic was mainly present as arsenopyrite(FeAsS) in the tailings,with range from 63% to 99%.Arsenic fractions in the sediments were mainly present as arsenite,arsenate and arsenopyrite.A high proportion of FeAsS in the sediments showed the typical character of a mining tailing contaminated river.The relative percentage contents of FeAsS and Res-As in the sediments gradually decreased with the increase of distance to the pollution sources,while arsenite and arsenate showed the opposite pattern.The results from sequential chemical extraction method and XANES spectra showed that the composition and trend of arsenic speciation in pollution sources and sediments of the Diaojiang River were generally in good agreement,although the quantitative data from the two methods showed some differences.