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

Abstract

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.

Radiocarbon and radiocesium in litter fall at Kawamata, ~ 45 km NW from the Fukushima Dai-ichi nuclear power plant (Japan)

“…Needles of the Japanese red pines elongated rapidly in June-July and the old needles usually fall between September and November [42]. The 14 C of leaves of evergreen and deciduous trees of same ages do not show significant differences and they are similar to that of the atmosphere in which they grow [6,[43][44][45]. Foliar  13 C in terrestrial vegetation vary as a function of vegetation species and of environmental parameters, such as, among others, light, temperature and water availability.…”

Reactor accident chemistry an update

“…As a result the 134 Cs to 137 Cs ratio in the leaves of the trees is an important clue to the origin of the cesium. The 134 Cs: 137 Cs ratio in the leaves which were exposed to fallout was the same as the leaves which grew on the tree after the accident (Xu et al, 2016).…”