Radioactive artificial ¹³⁷Cs and natural ⁴⁰K activity in 21 edible mushrooms of the genus Boletus species from SW China

This study, for the first time, presents the results of activity concentration determinations for ¹³⁷Cs and ⁴⁰K in a high number (21 species, 87 composite samples, and 807 fruiting bodies) of mushrooms of the genus Boletus from across Yunnan in 2011-2014 and Sichuan (Boletus tomentipes) using high-resolution high-purity germanium detector. Activity concentrations of ¹³⁷Cs demonstrated some variability and range from <4.4 to 83 ± 3 Bq kg^-1 dry biomass in caps and from <3.8 to 37 ± 3 Bq kg^-1 dry biomass in stipes, and of ⁴⁰K, respectively, from 420 ± 41 to 1300 ± 110 and from 520 ± 61 to 1300 ± 140 Bq kg^-1 dry biomass. No significant variations were observed regarding ¹³⁷Cs and ⁴⁰K activity concentrations among the same Boletus species from different sampling sites. No activity concentrations from ¹³⁴Cs were detected in any mushrooms. Internal dose rates estimated were from intake of 1 kg of mushrooms per annum for ¹³⁷Cs range for species and regions from around <0.0031 to 0.047 ± 0.003 μSv, while those for ⁴⁰K were from around 0.22 ± 0.04 to 1.2 ± 0.1 μSv. The overall intake of ¹³⁷Cs was low since low contamination was found in Boletus species.