Figure 2: Variations of As(III), As(V), Fe(II), and Fe(III) concentrations in microcosm experiments incubated under a range of biogeochemical conditions. (a) 16-m sediment with RB-W; (b) 16-m sediment with RB-S; (c) abiotic control of 16-m sediment; (d) 18-m sediment with RB-W; (e) 18-m sediment with RB-S; and (f) abiotic control of 18-m sediment.