Narrow Results

Particle-induced X-ray emission (PIXE) analysis of Lentinula edodes (Shiitake) mushrooms contaminated with radioactive cesium was performed to study relationships between concentrations of principal elements of shiitake mushrooms and their radioactive cesium levels. After the Fukushima nuclear disaster caused by the huge tsunami on March 11, 2011, we collected five shiitake samples in Marumori town, Miyagi Prefecture, on April 21, 2011. The mean radioactive level of the samples was 228 Bq/kg (the sum of ¹³⁴Cs and ¹³⁷Cs). The preliminary result of PIXE analysis using an internal standard method has demonstrated that shiitake mushrooms significantly collect rubidium as well as potassium. It is suggested that radioactive cesium is accumulated in shiitake just like rubidium during the course of potassium uptake.

Particle-induced X-ray emission (PIXE) analysis of Lentinula edodes mushrooms (Shiitake mushrooms) contaminated with radioactive cesium was performed to study relationships between concentrations of alkali elements in the shiitake mushroom samples and their radioactive cesium levels. The shiitake mushrooms were cultivated using radiocontaminated hard wood logs due to the nuclear power plant accident in Fukushima. The significant localization of radioactive cesium was found in the pileus region of the shiitake mushroom from autoradiographic observation. The concentrations of alkali elements in the shiitake sample were measured by PIXE analysis. The PIXE analysis has shown that the concentrations and transfer coefficients of potassium and rubidium in the pileus are much higher than the other parts of the shiitake sample as is the case of radioactive cesium. It is suggested that radioactive cesium is transferred into shiitake mushrooms in a manner similar to potassium and rubidium. The results of this work have shown the possibility to be able to use rubidium as an elemental tracer for radioactive cesium.

We performed particle-induced X-ray emission analysis to determine the quantitative relationships among alkali elements including radioactive Cs in Lentinula edodes (shiitake mushroom). The shiitake mushrooms were cultivated using radioactive Cs-contaminated hardwood logs, with Rb and stable Cs added to evaluate their concentrations by particle-induced X-ray emission (PIXE) analysis, as well as to measure the spatial distribution of radioactive Cs in the mushroom sample using an autoradiographic method. Radioactive Cs were strongly concentrated in the peripheral region of the mushroom pileus, whereas K, Rb, and stable Cs highly accumulated in the same region as radioactive Cs. We confirmed that the concentrations of K and Rb were basically proportional to that of stable Cs. In particular, a clear linear correlation was observed between the Rb and Cs concentrations. The results of this study indicate the availability of Rb as a substitute for Cs to study the accumulation of radioactive Cs in mushrooms.