Decontamination Efficiencies of Pot-Type Water Purifiers for (131)I, (134)Cs and (137)Cs in Rainwater Contaminated during Fukushima Daiichi Nuclear Disaster

Rainwater was contaminated by a large release of radionuclides into the environment during the Fukushima Daiichi nuclear disaster. It became a matter of concern for Japan when several water purification plants detected (131)I contamination in the drinking water. In the present study, the decontamination efficiency of two easily obtainable commercial water purifiers were examined for rainwater contaminated with (131)I, (134)Cs and (137)Cs. The water purifiers removed 94.2–97.8% of the( 131)I and 84.2–91.5% of the (134)Cs and (137)Cs after one filtration. Seven filtrations removed 98.2–99.6% of the (131)I and over 98.0% of the (134)Cs and (137)Cs. From a practical perspective, over the fourth filtrations were not needed because of no significant improvements after the third filtration.