Removal of radioactive iodine and cesium in water purification processes after an explosion at a nuclear power plant due to the Great East Japan Earthquake

Water Res. 2012 Sep 15;46(14):4397-404. doi: 10.1016/j.watres.2012.05.055. Epub 2012 Jun 7.


The presence of radionuclides at five water purification plants was investigated after an explosion at a nuclear power plant hit by the Great East Japan Earthquake on 11 March 2011. Radioactive iodine (¹³¹I) and cesium (¹³⁴Cs and ¹³⁷Cs) were detected in raw water in Fukushima and neighboring prefectures. ¹³¹I was not removed by coagulation-flocculation-sedimentation. ¹³¹I was removed by granular activated carbon (GAC) and powdered activated carbon (PAC) at a level of about 30%-40%, although ¹³¹I was not removed in some cases. This was also confirmed by laboratory-scale experiments using PAC. The removal percentages of ¹³¹I in river and pond waters by 25 mg dry/L of PAC increased from 36% to 59% and from 41% to 48%, respectively, with chlorine dosing before PAC. ¹³⁴Cs and ¹³⁷Cs were effectively removed by coagulation at both a water purification plant and in laboratory-scale experiments when turbidity was relatively high. In contrast, ¹³⁴Cs and ¹³⁷Cs in pond water with low turbidity were not removed by coagulation. This was because ¹³⁴Cs and ¹³⁷Cs in river water were present mainly in particulate form, while in pond water they were present mainly as cesium ions (¹³⁴Cs+ and ¹³⁷Cs+). However, the removal of ¹³⁴Cs and ¹³⁷Cs in pond water by coagulation increased markedly when ¹³⁴Cs and ¹³⁷Cs were mixed with sediment 24 h before coagulation.

MeSH terms

  • Cesium Radioisotopes
  • Charcoal / chemistry
  • Drinking Water / chemistry
  • Earthquakes*
  • Explosions*
  • Filtration
  • Flocculation
  • Iodine Radioisotopes
  • Japan
  • Nuclear Power Plants*
  • Radioactive Hazard Release*
  • Sewage / chemistry
  • Silicon Dioxide / chemistry
  • Water Pollutants, Radioactive / isolation & purification*
  • Water Purification / methods*


  • Cesium Radioisotopes
  • Drinking Water
  • Iodine Radioisotopes
  • Sewage
  • Water Pollutants, Radioactive
  • Charcoal
  • Silicon Dioxide