Chemical speciation determines Se solubility and thereforeits bioavailability and potential for transport in theenvironment. In this study we investi
gated the speciationof Se in soil developed on reclaimed mine sites in the U.S.Western Phosphate Resource Area (WPRA) usin
g micro-X-ray absorption near-ed
ge structure (
![](/ima<font color=)
ges/entities/m
gr.
gif">-XANES) spectroscopyand micro-X-ray fluorescence (
![](/ima<font color=)
ges/entities/m
gr.
gif">-XRF) mappin
g. Seleniumwas nonuniformly distributed in the soils and positivelycorrelated with Fe, Mn, Cu, Zn, and Ni. Sixteen points ofinterest (POI) from three soil samples were analyzed with
![](/ima<font color=)
ges/entities/m
gr.
gif">-XANES spectroscopy. The XANES data indicated thatSe is present in the soils in at least three oxidation states,Se(-II, 0), Se(IV), and Se(VI). Selenides or elemental Sedominated 7 of the 16 POI. Selenate was the dominant speciesat only one of the POI. The remainin
g ei
ght POI werecomposed of both Se(IV) and Se(VI), with minor Se(-II, 0)contributions. The results of this research su
ggest thatthe reduced Se species in the soil parent material areoxidizin
g to Se(VI), one of the more mobile species of Se inthe environment. This information can be used to betterpredict and mana
ge Se availability in soils.