Figure 3: Variations of As(III), As(V), Fe(II) and Fe(III) concentrations in microcosm incubation experiments containing sterilized core sample (18 m) amended with (a) non-sterilized groundwater, (b) non-sterilized groundwater and acetate, (c) sterilized groundwater and RB-W, (d) sterilized groundwater and acetate and (e) sterilized groundwater only.