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by Yuichi TOMIOKA This study investigated the role of jarosite in arsenic removal using flask shaking experiments in diluted sulfuric acid solutions (pH1-3). Jarosite was synthesized and the chemical composition of the jarosite was K 0.54 (H 3 O) 0.46 Fe 2.38 (SO 4 ) 2 (OH) 6 . The shaking experiments found that As(V) was removed by the jarosite but As(III) was not removed. The mechanisms of As(V) removal were adsorption on the jarosite and co-precipitation with Fe(III) extracted from jarosite. The removal of As(V) from the liquid phase were increased with increasing pH, indicating that the adsorption of As(V) and SO 4 2-is competitive or that ionic As species (H 2 AsO 4 -) is selectively adsorbed. The results suggest that jarosite is a sink for As(V) in acidic polluted environments.

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This study evaluates a method to estimate shallow groundwater intrusion in and around a large underground research facility Mizunami Underground Research Laboratory-MIU. Water chemistry, stable isotopes δD and δ 18 O , tritium 3 H , chlorofluorocarbons CFCs and sulfur hexafluoride SF 6 in groundwater were monitored around the facility from 20 m down to a depth of 500 m , for a period of 5 years. The results show that shallow groundwater inflows into deeper groundwater at depths of between 200-400 m. In addition, the content of shallow groundwater estimated using 3 H and CFC-12 concentrations is up to a maximum of about 50%. This is interpreted as the impact on the groundwater environment caused by construction and operation of a large facility over several years. The concomitant use of 3 H and CFCs is an effective method to determine the extent of shallow groundwater inflow caused by construction of an underground facility.