Estimation of Radioactive Cesium Concentration in Persimmon Fruits of Different Branches of Individual Trees

Abstract

This study investigated the variations in ¹³⁷Cs concentrations in the fruits and leaves of persimmon trees, which had been affected by radioactive cesium for several years. The trees were divided into lateral or main branches, and ¹³⁷Cs concentrations of fruits and leaves in the branches were measured. The ¹³⁷Cs concentration differed among the fruits of the branches of the same tree, and the difference in ¹³⁷Cs concentration in the fruits of each branch was confirmed for multiple years. A difference in ¹³⁷Cs concentration of approximately ten times was found between the fruits of each branch on the same tree. In addition, a correlation was found between ¹³⁷Cs concentrations in fruits and leaves. These results suggest that a difference might exist in the ¹³⁷Cs concentration of each branch of the tree at the time of fallout in 2011, and it was considered that the difference might persist.