Carbon, cesium and iodine isotopes in Japanese cedar leaves from Iwaki, Fukushima

Japanese cedar leaves from Iwaki, Fukushima were analyzed for carbon, cesium and iodine isotopic compositions before and after the 2011 nuclear accident. The Δ¹⁴C values reflect ambient atmospheric ¹⁴C concentrations during the year the leaves were sampled/defoliated, and also previous year(s). The elevated ¹²⁹I and ^134,137Cs concentrations are attributed to direct exposure to the radioactive fallout for the pre-fallout-expended leaves and to internal translocation from older parts of the tree for post-fallout-expended leaves. ¹³⁴Cs/¹³⁷Cs and ¹²⁹I/¹³⁷Cs activity ratios suggest insignificant isotopic and elemental fractionation during translocation. However, fractionation between radioiodine and radiocesium is significant during transportation from the source.