Differences in Radioactive Caesium-137 Concentrations in Young Persimmon Fruit from Trees in the Same Orchard

Abstract

We measured ¹³⁷Cs concentrations in the young persimmon fruit of each tree in 4 orchards in Fukushima prefecture. We found that the ¹³⁷Cs concentrations in the young fruit differed even within the same orchard, and it was revealed that there were a few trees that yielded fruit with high ¹³⁷Cs concentration. In addition, the radioactive contamination density on the ground surface as measured by the walking type radioactivity measurement system ‘KURAMA-II,’ the radiation count rate on the surface of the tree trunk, and the stem perimeter of the tree were measured. These results were compared with the ¹³⁷Cs concentrations of the young fruit. As a result, no relation was observed between each measured value and the ¹³⁷Cs concentration of the young fruit, and it was shown that it is difficult to estimate which trees have a high risk of radioactive contamination by these methods.