RADIOISOTOPES

Due to the accident at the Fukushima Daiichi Nuclear Power Station of the Tokyo Electric Power Company, fruit trees such as persimmons were contaminated with radioactive materials. Eight years after the accident, relatively young lateral branches of persimmon trees, which had higher ¹³⁷Cs concentrations in fruit than other trees, were sampled, and the ¹³⁷Cs and ¹³³Cs concentrations in the branches, leaves, and fruits were measured. A correlation was observed between the ¹³⁷Cs concentrations in fruits and branches. ¹³⁷Cs concentrations were different among the branches as well as in leaves and fruits. There was a correlation between ¹³⁷Cs and ¹³³Cs concentrations in the fruits, leaves, and branches. Therefore, it is possible that some of the ¹³⁷Cs that fell on the bark may have migrated to the internal trees and accumulated in the same part as the ¹³³Cs absorbed from the roots, and they were similarly translocated to the fruits via new branches.