Radioactivity concentrations of 137Cs and 40K in basidiomycetes collected in Taiwan

Radioactivity concentrations of 137Cs and 40K in 64 mushroom samples belonging to 16 species of basidiomycetes collected at various locations in Taiwan have been measured in 1994. All of the samples were mushrooms cultivated indoors. The concentrations of 137Cs in many samples were below the limit of detection (< 1.0 Bq kg−1 dry weight), and 134Cs was not detected in any of the samples. The radioactivity concentration ranges of 137Cs and 40K in basidiomycetes were < 1.0–7.3 Bq kg−1 dry weight and <50–1230 Bq kg−1 dry weight, respectively. The transfer factors of F. velutipes, G. lucidum and L. edodes from sawdust (growing substrate) to mushroom were 10, 10.2, <3.8 for 137Cs, and 7.2, 1.6, 1.8 for 40K, respectively. The effective dose equivalent due to the dietary intake of radiocesium through mushrooms for the Taiwanese people was estimated to be only 4.4 × 10−10 Sv y−1.