The effects of microorganism, akaganeite nanoparticles, and a mixture of both on the mobility of dissolved As(V) were investigated through experiments using columns filled with glass beads or natural, As-contaminated soil. In the case of glass beads column, nanoparticles enhanced the concentration of dissolved As in the effluent (0.48 mg/L) when compared with a control (0.17 mg/L) after 7 days. In microbial (0.04 mg/L) and mixture columns (0.08 mg/L), dissolved As concentrations were lower than the control. However, injection of microbe into the column filled with natural soil led to highly enhanced extraction of As from the soil (1.39 mg/L), whereas no significant difference in the amount of dissolved As was observed between nanoparticles (0.28 mg/L) and control (0.18 mg/L) columns. The results indicated that the interaction of As(V) with microorganism and Fe-nanoparticles may be controlled by the kind of geological media, i.e., crystalline aquifer or soil, contaminated with As(V).