Depositional records of plutonium and (137)Cs released from Nagasaki atomic bomb in sediment of Nishiyama reservoir at Nagasaki

J Environ Radioact. 2008 Jan;99(1):211-7. doi: 10.1016/j.jenvrad.2007.11.010. Epub 2008 Jan 2.


In a sediment core of Nishiyama reservoir at Nagasaki city, depth profiles of (240)Pu/(239)Pu isotopic ratio, (239+240)Pu and (137)Cs activities were determined. Sediments containing plutonium and (137)Cs, which were deposited immediately after a detonation of Nagasaki atomic bomb, were identified in the core. Observed below the sediments were macroscopic charcoals, providing evidence for initial deposit of the fallout of the Nagasaki atomic bomb. This is the first entire depositional records of plutonium and (137)Cs released from the Nagasaki atomic bomb together with those from atmospheric nuclear tests.

MeSH terms

  • Cesium Radioisotopes / analysis*
  • Geologic Sediments / chemistry*
  • Japan
  • Plutonium / analysis*
  • Water Pollutants, Radioactive / analysis*


  • Cesium Radioisotopes
  • Water Pollutants, Radioactive
  • Plutonium