¹³⁷Cs Activity Concentration in Japanese Persimmon Fruit at Different Growth Stages

Abstract

In 5 to 6 years after the accident, we investigated the ¹³⁷Cs activity concentration in the fruit and leaves of Japanese persimmon ‘Hachiya’ at different growth stages. The ¹³⁷Cs concentration tended to be the highest in young fruit. In mid-September, the ¹³⁷Cs concentration dropped to the lowest level with fruit growth. After that, the concentration of some fruit gradually increased with their maturation. However, the concentration change after mid-September could not be observed clearly since variation in the individual fruit concentration was large. It was considered that we could reduce the risk of high concentrations by harvesting fruit at a suitable time because we could not deny the possibility of the ¹³⁷Cs concentration of fruit rising. In the case of leaves, the ¹³⁷Cs concentration tended to be the highest in young fruit and decrease with growth.