Relations of As concentrations among groundwater, soil, and bedrock in Chungnam, Korea: Implications for As mobilization in groundwater according to the As-hosting mineral change

► Relations among As levels in rocks, soils, and groundwater are investigated. ► Shallow groundwaters are low in As level while the soil As contamination is serious. ► Weathering of arsenopyrite-bearing rock spreads the soil As contamination. ► Adsorption onto Fe (hydr)oxides in soil at low pH caused the low As concentration.