放射光源X線吸収分光法を駆使した地球表層でのヒ素やアンチモンの挙動解明

抄録

Study on behaviors of elements in aquatic environments gives us important knowledge to understand mechanisms for water resource cycle, rock weathering, and pollution of surface water and groundwater. We have investigated fates of toxic elements, arsenic and antimony, in aquatic environments such as sediment and soil. Particularly, the studies have been performed focusing on chemical processes in aquatic environment, which leads to better understanding of principle factors that control their fates. The chemical processes were discussed based on atomic level information revealed by direct chemical speciation with synchrotron-based X-ray absorption fine structure (XAFS) technique. The behaviors of arsenic and antimony drastically change depending on redox condition, since both elements have several oxidation states. Hence, we comprehensively considered the behaviors both in oxidizing and reducing environments by direct chemical speciation using the XAFS. In this paper, I briefly introduce basis and advantages of XAFS technique, and discuss various factors that can influence the behavior of arsenic and antimony in aquatic environments.