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3319675 
Journal Article 
Tree-ring strontium-90 and cesium-137 as potential indicators of radioactive pollution 
Kagawa, A; Aoki, T; Okada, N; Katayama, Y 
2002 
Yes 
Journal of Environmental Quality
ISSN: 0047-2425
EISSN: 1537-2537 
AMER SOC AGRONOMY 
MADISON 
31 
2001-2007 
To examine whether tree rings can be used to detect or assess local historical Sr-90 or Cs-137 fallout, such as that resulting from the Hiroshima atomic bomb, radial distribution of Sr-90 and Cs-137 in trees was examined. We studied a gymnosperm [Japanese cedar, Cryptomeria japonica (L. L) D. Don] and an angiosperm (Japanese persimmon, Diospyros kaki Thunb.) tree species from the vicinity of the atomic bomb hypocenter, and from other locations in Japan. A significant amount of Cs-137 was detected in tree rings formed before 1945, indicating lateral migration of Cs. In contrast, the specific activity of Sr-90 in the Hiroshima Japanese cedar showed the highest level in 1945, due to relatively immobile characteristics of Sr compared with Cs. Strontium-90 and Sr analyses in tree rings helped identify and distinguish between residual Sr-90 activity from the Hiroshima atomic bomb and the atmospheric nuclear testing. This indicates the possibility of detecting or assessing previous local Sr-90 pollution through with treering analysis.