The distribution of radiocesium in a moso bamboo (Phyllostachys pubescens) forest in Fukushima Prefecture, Japan

Abstract

To clarify the distribution of radiocesium (137Cs) in a Moso bamboo (Phyllostachys pubescens) forest in Fukushima Prefecture after the Fukushima Daiichi Nuclear Power Plant Accident, we visually and quantitatively investigated 137Cs contamination levels in each organ of the bamboos, which sprouted before 2010 and after 2011, in 2012 and 2014. From the analysis on the bamboo samples taken in 2012, the highest 137Cs concentration was found in the node parts of both the culms and branches in the before-2010 bamboo due to the direct fallout containing 137Cs. This fact suggests a long-term contamination with little leaching of 137Cs in the bamboo forest. From similar 137Cs concentrations in each organ among the different-aged bamboos, it was supposed that 137Cs diffused from before-2010 bamboo to the 2011-sprouted bamboo just after the accident and also that the root uptake of 137Cs might contribute to the contamination in the 2011-sprouted bamboo. However, we did not find the evidence of root uptake in 2014 from the results of 137Cs distribution in the root system. These results suggested that 137Cs absorbed just after the accident has been diffusing throughout the bamboo forest via the rhizome system.