The quantitative relationships among alkali elements and the availability of Rb as a substitute for radioactive Cs in Lentinula edodes

Abstract

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.