Fig. 5. Pre-edge region in edge-normalized P K-XANES spectra for PO₄ adsorbed on ferrihydrite (ferri.—June 2002 and October 2002 data) or boehmite at various concentrations at pH 6.0 ± 0.1 along with averaged standards for PO₄ adsorbed on each mineral. Numbers in the legend denote adsorbed PO₄ concentrations in mmol kg^–1.