The Transfer of radiocesium from the bark to the stemflow of chestnut trees () contaminated by radionuclides from the Fukushima Dai-ichi Nuclear Power Plant accident

Sasaki, Yoshito ; Abe, Hironobu ; Mitachi, Katsuaki; Watanabe, Takayoshi ; Ishii, Yasuo; Niizato, Tadafumi  

We report the behavior of radiocesium on the tree bark and its transfer into the stemflow of chestnut in a forest in Fukushima. The radiocesium concentration is greatest in 2-cm stem, less in 5-mm stem, and least in the leaves. In the 2-cm stem, the radiocesium concentration of the bark was approximately 10 times that of wood. The average Cs-137 concentration of the dissolved fraction of stem flow was about 10 Bq/L; the pH was nearly constant at 5.8. A strong positive correlation was observed between the radiocesium concentration and the electrical conductivity of the dissolved fraction of stemflow; this result suggests that radiocesium and electrolytes have the same elution mechanism from the tree. Some of the particles in the particulate fraction of the stem flow was strongly adsorbed radiocesium.