Environ. Sci. Technol. 2010, 44, 1281–1287
µ-XANES Evidence for the Reduction of Sb(V) to Sb(III) in Soil from Sb Mine Tailing S A T O S H I M I T S U N O B U , * ,† Y O S H I O T A K A H A S H I , ‡,§ A N D YASUKO TERADA| Institute for Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan, Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan, Laboratory for Multiple Isotope Research for Astro- and Geochemical Evolution (MIRAGE), Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan, and SPring-8, Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5158, Japan
Received September 29, 2009. Revised manuscript received December 22, 2009. Accepted December 30, 2009.
The aim of this study was to determine the mechanism of Sb immobilization occurring under reductive soil conditions. In this work, we investigated the distribution and speciation of Sb in reductive soil formed in Sb mine tailing by micro-X-ray absorption near edge structure spectroscopy (µ-XANES) and electron probe microanalyzer (EPMA). EPMA and Fe K-edge µ-XANES analyses of the soil grains indicated that Sb in soil was strongly associated with Fe(III) hydroxides secondarily formed during sedimentation. The Sb concentrations in Sb hotspot were found to be as high as 10-30 wt % (as Sb2O5). We also found quartz particles coated by secondary rims bearing Fe(III) hydroxides and Sb. The Sb K-edge µ-XANES analyses of the rims showed that a significant amount of Sb(III) was present only at the surfaces of the rims (thickness
