“…The speciation and bonding environment of U in soil, sediment, and clay minerals has been examined with a variety of spectroscopic techniques such as FT-infrared (FT-IR), FT-Raman, time-resolved luminescence, X-ray photoelectron and X-ray diffraction (XRD) (BURNS et al, 1997;BARGAR et al, 1999;CEJKA, 1999 and references therein;HANCHAR, 1999 and references therein;BUCK et al, 1996;MORRIS et al, 1996;CHISHOLM-BRAUSE et al, 1994;WERSIN et al, 1994;BIWER et al, 1990;HO and MILLER, 1986). Synchrotron-based techniques such as extended X-ray absorption fine-structure (EXAFS) and X-ray absorption near-edge structure (XANES) have been used to determine the identification, location and number of atoms in the local structural environment and the oxidation state of U within a variety of environmentally relevant media (MOYES et al, 2000;DUFF et al, 2000;BARGAR et al, 1999;DENECKE et al, 1998;THOMPSON et al, 1997;BURNS et al, 1997;ALLEN et al, 1996;MORRIS et al, 1996;BERTSCH et al, 1994;WAITE et al, 1994;WERSIN et al, 1994;DENT et al, 1992;FARGES et al, 1992).…”