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

Abstract

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.

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

“…The activity concentrations of 137 Cs in mushrooms from Yunnan in this study and in limited samples of mushrooms collected in Yunnan after the Fukushima accident and examined so far were usually low, i.e., < 10 Bq kg −1 d.b. (Falandysz et al 2015a , b , 2016a and 2017 ; Tuo et al 2014 ; Wang et al 2015 ). These results were much lower when compared to reported activity concentrations of 137 Cs in mushrooms foraged in eastern, central, and western Europe after the Chernobyl catastrophe—as reviewed by Duff and Ramsey ( 2008 ) and others (Falandysz and Borovička 2013 ; Cocchi et al 2017 ; Grodzinskaya et al 2013 ; Kalač 2001 ).…”

“…It was expected that the deposition of airborne 137 Cs in the subalpine area of Minya Konka from global fallout, and with absence of local and regional sources of emission, should be better reflected in mushrooms and topsoil from there, compared to mushrooms and topsoil from the neighboring northern, central, and southern regions of Yunnan Province. Available data on radioactivity levels in mushrooms from some main producing countries such as China are considered as insufficient (Falandysz et al 2015a , b , 2016a and 2017 ).…”

“…Food safety after Fukushima became the most pressing and most current issue with respect to radionuclide contaminations, since the results of food monitoring campaigns in Japan showed a specific contamination with 137 Cs of mushrooms and meat of game animals, such as wild boars ( Sus scrofa ), which eat mushrooms (Merz et al 2015 ). Many mushrooms growing in the wild are known to be highly prone to contamination with artificial or natural radioactive compounds but also with heavy metals deposited or contained in the top layer of forest soils due to geochemical anomalies of parent soil material (Falandysz et al 2017 ; Kirchner and Daillant 1998 ; Vaaramaa et al 2009 ). Mushrooms from the wild are valued as organic food, and they still accumulate radionuclides and especially 137 Cs from the environment as a result of atmospheric nuclear weapon detonations and after major nuclear accidents (Betti et al 2017 ; Chatterjee et al 2017 ; Cocchi et al 2017 ; Grodzinskaya et al 2013 ; Letho et al 2013 ; Saniewski et al 2016 ; Steinhauser and Steinhauser 2016 ; Strumińska-Parulska et al 2016 ).…”

210Po and 210Pb bioaccumulation and possible related dose assessment in parasol mushroom (Macrolepiota procera)

“…Naturally or artificially elevated content of some metallic elements in forest topsoil can result in heightened accumulation in mushrooms (Kojta et al 2012 ). Concentrations of Hg, Cd, and Pb can be relatively high both in certain terrestrial saprotrophs but also in ectomycorrhizal fungi that usually accumulate higher amounts of alkali metals, Rb, and Cs (Borovička and Řanda 2007 ; Falandysz et al 2015 , 2017a , b , c , d ; Řanda and Kučera 2004 ).…”

“…As stated by the authors Falandysz and Borovička ( 2013 ), there is no reason for mushrooms to discriminate between stable and radioactive isotopes of elements when absorbed and accumulated in the mushroom flesh, while their accessibility and availability at sites where the mycelium lives can be different. Frequently studied is 137 Cs that polluted the surface of the Earth due to global radioactive fallout after using and testing of nuclear weapons and from nuclear power plant accidents but also 40 K that is of natural terrestrial origin (Mietelski et al 2010 ; Steinhauser et al 2014 ; Falandysz et al 2016 ; Zalewska et al 2016 ; Falandysz et al 2017d ). Other radionuclides studied in mushrooms included 210 Po, 210 Pb, 234,238 U, 228,230,232 Th, 238 Pu, 239 + 240 Pu (Mietelski et al 2002 ; Vaaramaa et al 2009 ; Guillén and Baeza 2014 ; Strumińska-Parulska et al 2016 ).…”