Sulfur Speciation in the Surface Sediments of Lakes from Different Regions,China: Characterization by S K-Edge XANES Spectroscopy

X-ray absorption near edge structure (xanes) spectroscopy affords the opportunity to determine redox status for element s in the aquatic ecosystems. however,there have been relatively few studies of s xanes spectroscopy in the terrestrial aquatic ecosystems. in this study,xanes technology was used to examine changes in s speciation in the sediments collected from taihu lake,qinghai lake,dianchi lake,caohai lake,and hongfeng lake located in distinct geological background areas of china. the results showed that sedimentary s in qinghai lake has a high proportion of sulfate averaged 88.9% due to physical weathering of watershed rocks,while deposited s in taihu lake has a high fraction of intermediate s (36.5%),which may be the response of the agricultural nonpoint source pollution in drainage basin. the three lakes located in southwest china have similar composition characteristics of s species,indicating similar s sources including chemical weathering of carbonate and atmospheric deposition. 60-90% of s compounds in the surface sediments were in the form of sulfate and fes. in deeper layers,the ratio of fes2 and the intermediate s significantly increased,suggesting rapid processes of sulfate reduction and sulfide reoxidation with the increasing depths. © 2016 wang jingfu et al.