The radioactive isotope, ⁴⁰K, of naturally occurring potassium (0.012%) is present in the Earth’s crust in a low percentage of all potassium, leading to its presence in almost all foodstuffs. The impact of ⁴⁰K activity concentrations was assessed in wild and cultivated edible mushrooms and in growing substrates. Samples were analysed by gamma spectroscopy. In the wild mushroom species, the average activity concentration of ⁴⁰K was 1291 Bq kg⁻¹ dry weight (dw), approximately 140 Bq kg⁻¹ fresh weight (fw), with a range of average values per species from 748 in Lactarius deliciosus to 1848 Bq kg⁻¹ dw in Tricholoma portentosum. The cultivated species presented an average value of 1086 Bq kg⁻¹ dw; and the soils, compost of cultivation and wood of substrate are 876, 510 and 59.4 Bq kg⁻¹ dw, respectively. The total K content reached a maximum of 59,935 mg kg⁻¹ dw in T. portentosum. The transfer factors (TF > 1) suggested that mushrooms preferentially bioconcentrated ⁴⁰K. Cantharellus cibarius, Craterellus tubaeformis, Hydnum repandum and T. portentosum by most TF could be considered as bioindicators of ⁴⁰K. Taking into account that the annual radiation dose of ⁴⁰K due to the average consumption of mushrooms analysed (0.15 μSv/year) is very low, it can be concluded that the consumption of these mushrooms does not represent a toxicological risk for human health. Finally, according to the total K content, from the nutritional point of view, these mushrooms could be considered as a potential source of potassium for the human diet.

Mushrooms are rich sources of organic nutrients (especially proteins). However, they can excessively accumulate metals in their fruiting bodies that pose a risk to human health. The aim of this study was the determination of Cd, Co, Cu, Fe, Mn, Ni, Pb, and Zn contents, daily intake, and health risk index values of some mushroom species collected from the eastern Black Sea region of Turkey (Arsin, Trabzon). The samples were collected from hazelnut gardens that are free from industrial pollution and have a low population density. As a result of elemental analysis, it was determined that the concentration ranges of Cd, Co, Cu, Fe, Mn, Ni, Pb, and Zn in the mushrooms were as follows: 0.29–9.11, 0.04–3.70, 0.01–8.29, 0.18–20.82, 3.1–79.8, 5.2–673.0, 14.9–752.0, 63.0–7769.0 mg/kg dry weight. Daily intakes of all the elements were found to be below the reference dose in Fistulina hepatica, Hydnum repandum, Macrolepiota procera, and Tapinella atrotomentosa. Amanita caesarea, Agrocybe praecox, Amanita vaginata, Cantharellus cibarius, Craterellus cornucopioides, Daedalea quercina, Gymnopus dryophilus, Ganoderma lucidum, and Infundibulicybe gibba were found to have high risk index values especially with respect to Cd, Co, and Pb. According to Pearson correlation analysis, the correlations between Fe–Mn (0.840, p < 0.01) and Pb–Ni (0.7540, p < 0.01) couples are significant.

The aim of this study was to determine the element content of wild edible and inedible mushroom species (Agaricus campestris, Armillaria ostoyae, Boletus reticulatus, Bondarzewia mesenterica, Bovistella utriformis, Cantharellus cibarius, Marasmius oreades, Megacollybia platyphylla, Meripilus giganteus, Neoboletus erythropus, Panellus stipticus, Phaeotremella foliacea, Pleurotus ostreatus, Podoscypha multizonata, Russula aurea, R. chloroides, R. virescens, T. versicolor, Trametes gibbose, and Trichaptum biforme) collected from the Belgrad Forests and the Ilgaz Mountain National Park. Based on the results of elemental analyses, daily metal intake (DMI) and health risk index (HRI) values of edible mushrooms collected from both localities were also calculated. As, Cd, Cr, Se, P, Hg, Cu, Mn, Fe, Zn, Al, Ca, Mg, and K contents of mushrooms were in the ranges of 0.16–3.45, 0.09–2.4, 0.15–2.34, 0.3–8.13, 0.28–11.44, 14.03–37.81, 3.87–108.57, 6.18–149.77, 11.9–776.1, 5.4–317.4, 7.4–355.2, 15.4–3517.3, 266.0–2500.0, and 628.0–24083.0 mg/kg dry weight, respectively. As a result of the DMI and HRI analyses, Cu concentration of B. utriformis (DMI: 46.53 μg/kg body weight/serving, HRI: 1.16) and Cd concentrations of A. campestris (DMI: 0.49 μg/kg body weight/serving, HRI: 1.36), A. ostoyae (DMI: 1.03 μg/kg body weight/serving, HRI: 2.86), B. utriformis (DMI: 0.52 μg/kg body weight/serving, HRI: 1.44), and P. ostreatus (DMI: 0.45 μg/kg body weight/serving, HRI: 1.24) were found to exceed the legal limits determined by authorities. It was concluded that the species collected from the regions in question should be consumed in a controlled manner.

Mushrooms (Cantharellus cibarius and Amanita fulva) were blanched (parboiled) and pickled using different treatment conditions with the aim of carrying out the study into effect on removal of toxic mercury (Hg) accumulated in flesh. Blanching of fresh sliced C. cibarius caused leaching of Hg by approximately 15%, while loss of up to 35% was observed for sliced, deep-frozen fruit bodies. The rate of Hg leaching from the C. cibarius in practice was the same when blanched for 5 or 15 min irrespective of potable or deionized water used. Pickling of blanched C. cibarius with a diluted vinegar marinade had only a minor, if any, effect on removal of Hg and was without effect on blanched caps of A. fulva. Mercury was better extracted by boiling water from the fresh caps of A. fulva (56 ± 2% of the initial level in fresh caps) than from the fresh or frozen fruit bodies of C. cibarius. Total leaching rate of Hg from a pickled C. cibarius when fresh fruit bodies were processed was between 15 ± 5 and 37 ± 7% (median range 13–34%), and when deep-frozen fruit bodies were processed, it was between 37 ± 7 and 39 ± 8% (median range 34–39%). Pickling of the caps of A. fulva with diluted vinegar did not increase leaching of Hg. Blanching of mushrooms before future culinary use is a simple procedure recommended in reduction of contamination with Hg of cooked mushroom meal. Pickling had little if any effect on further removal of Hg from the initially blanched mushrooms.

The activity concentrations of ¹³⁷Cs and ⁴⁰K in mushrooms of the genus Cantharellus (Cantharellus cibarius, Cantharellus tubaeformis, and Cantharellus minor) collected across Poland from 1997 to 2013 and in Yunnan province of China in 2013 were determined using gamma spectrometry with an HPGe detector, respectively. Activity concentrations of ¹³⁷Cs in C. cibarius from the places in Poland varied from 64 ± 3 to 1600 ± 47 Bq kg⁻¹ db in 1997–2004 and 4.2 ± 1.2 to 1400 ± 15 Bq kg⁻¹ db in 2006–2013. In the Chinese Cantharellus mushrooms, the activity level of ¹³⁷Cs was very low, i.e., at a range <1.2 to 1.2 ± 0.6 Bq kg⁻¹ dry biomass. The natural radionuclide ⁴⁰K was at similar activity level in C. cibarius collected across Poland and in China, and fluctuations in levels of ⁴⁰K over the years and locations in Poland were small. In C. cibarius from diverse sites in Poland, content of ¹³⁷Cs highly fluctuated in 1998–2013 but no clear downward trend was visible (Fig. 1). Published activity levels of ¹³⁷Cs in fruitbodies of Cantharellus such Cantharellus californicus, Cantharellus cascadensis, C. cibarius, Cantharellus cinnabarius, Cantharellus formosus, Cantharellus iuteocomus, Cantharellus lutescens, Cantharellus minor, Cantharellus pallens [current name C. cibarius], Cantharellus subalbidus, Cantharellus subpruinosus, and C. tubaeformis collected worldwide were compared. In the Polish cuisine, mushrooms of the genus Cantharellus are blanched before frying or pickling, and this kind of treatment, and additionally also pickling, both very efficiently remove alkali elements (and radioactivity from ¹³⁴/¹³⁷Cs) from flesh of the species.

In the present study, the composition of bio-elements (K, Na, Mg, Ca, Fe, Cu, Zn) and toxic elements (Ag, Cd) in seven edible mushrooms from the rural and woodland region of Morąg (north-eastern Poland) and the rural and industrial region of the Tarnobrzeska Upland (south-eastern Poland) were investigated using a validated method. The species examined were Boletus edulis, Cantharellus cibarius, Leccinum aurantiacum, Leccinum versipelle, Lycoperdon perlatum, Suillus luteus, and Xerocomus subtomentosus. Final determination was carried out by flame atomic absorption spectroscopy (FAAS) after microwave-assisted decomposition of sample matrices with solutions of concentrated nitric acid in the pressurized polytetrafluoroethylene vessels. The contents of the alkali elements and alkali earth elements were determined in the species surveyed. The alkali elements, earth alkali elements, and transition metals (Ag, Cu, Zn, Fe, and Mn) were at typical concentrations as was determined for the same or similar species elsewhere in Poland and Europe. The results may suggest a lack of local and regional emissions of those metallic elements from industrialization of some sites in the Tarnobrzeska Plain. Cadmium was at elevated concentrations in L. versipelle from the Tarnobrzeska Plain but the reason—pollution or geogenic source—was unknown, while it was at typical concentrations in other species.