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The adsorption of AuCl₄⁻, AuCl₂⁻ and Au(S₂O₃)₂³⁻ at low Au concentrations relevant to most supergene waters on geothite, birnessite and soil humic acid was investigated at pH 4, pH 2–11.6, in 0.01 and 0.1 M NaNO₃ solutions. At pH 4 and two electrolyte strengths, the adsorption isotherms for the two Au chloride complexes are well described by the Freundlich equation. The Freundlich parameter 1/n reflects the heterogeneity of the birnessite surface and the nonlinearity of Au adsorption isotherm. The adsorption of Au(S₂O₃)₂³⁻ is significantly greater than that of AuCl₄⁻ on birnessite, but the adsorption of Au(S₂O₃)₂³⁻ is significantly smaller for geothite and humic acid. The adsorption of AuCl₄⁻ on birnessite and geothite is depressed by increasing electrolyte strength. As birnessite could only adsorb gold anions specifically and goethite could adsorb gold anions by anionic exchange and specific adsorption …