Artificial 137Cs and natural 40K in mushrooms from the subalpine region of the Minya Konka summit and Yunnan Province in China

A study on Cs-137 pollution and activity concentrations of K-40 in mushrooms of the genera Cortinarius, Leccinum, Russula, Tricholoma, Tylopilus, and Xerocomus from two neighboring regions in southwest China in 2010-2013 revealed different patterns of pollution with Cs-137, which seemed to be highly dependent on climate conditions. Tricholoma matsutake was collected in Yunnan before and after the Fukushima Dai-ichi nuclear accident and showed similar contamination with Cs-137. Mushrooms from the elevation of 2800-3480 m above sea level on the east slope of Minya Konka and forest topsoil showed higher contamination with Cs-137 than mushrooms from the highlands of Yunnan. In detail, the activity concentration of Cs-137 in caps of mushrooms from Minya Konka were in the range 62 +/- 6-280 +/- 150 Bq kg(-1) dry biomass and from Yunnan at < 4.4-83 +/- 3 Bq kg(-1) dry biomass. The climate in the region of the Minya Konka is much colder than in Yunnan, which seems to favor deposition of Cs-137 at higher altitudes from global atmospheric circulation. The activity concentration of K-40 in mushrooms and soils highly exceeded that of Cs-137. The assessed annual effective doses for Cs-137 in 1 kg of consumed mushrooms of the genera Leccinum and Xerocomus in Yunnan were low, i.e., in the range < 0.0043-0.049 +/- 0.004 mu Sv, while those for K-40 were 0.26 +/- 0.02-0.81 +/- 0.09 mu Sv.