Accumulation of elements by edible mushroom species: part I. Problem of trace element toxicity in mushrooms

Pleurotus extract-mediated selenium and zinc nanoparticles exhibited improved yield of biofortified fruit bodies

The current study was aimed for the generation of Pleurotus extracellular extract-mediated selenium and zinc-oxide nanoparticles (NPs). The Pleurotus djamor (PD) and Pleurotus sajor-caju (PSC) extracts were incubated with different concentrations of sodium selenate and zinc acetate to yield BioSeNPs and BioZnONPs. The NPs formation led to visual color change (brick-red and white for Se and Zn nanosols, respectively). The synthesized NPs were spherical with size of 124 and 68 nm and 84 and 91 nm for PD and PSC BioSeNPs and BioZnONPs respectively. The UV absorbance peaks were recorded at 293.2 and 292.2 nm and 365.9 and 325.5 nm for BioSeNPs and BioZnONPs derived from PD and PSC respectively. FT-IR spectroscopy indicated specific functional group adoration on metal-based NPs. On supplementation in straw, these NPs improved the fruit body yield besides enhancing their protein and Se/ Zn contents. These biofortified mushrooms could be potential dietary supplement/ nutraceutical.

Accumulation of pollutants from fly ash in Pleurotus ostreatus and a substrate based on coffee grounds by elemental analysis using the ICP-OES method and photometric method

The substrate mixtures were created in the study, using spent coffee grounds for Pleurotus ostreatus cultivation with the addition of straw and fluidized bed ash at 5 and 10 percent by weight relative to the total weight of coffee grounds. In order to determine the ability to accumulate heavy metals and the possibility of further waste management, analyses of micro- and macronutrients, biogenic elements, as well as the metal content of fungal fruiting bodies, mycelium and post-cultivation substrate were performed. The addition of 5 percent resulted in slower growth of mycelium and fruiting bodies, and with the addition of 10 percent, the growth of fruiting bodies was completely inhibited. The accumulation of elements such as (Cr), (Cu), (Ni), (Pb) and (Zn) was reduced in the fruiting bodies grown on the substrate with the addition of 5 percent fly ash, compared to spent coffee grounds without additives.

Effect of Two Feed Additives-One Multicomponent Based on Nanosilica and the Second Containing Mycelium of Lentinula edodes Fortified with Selenium-On Production Parameters and Histological Analysis of Calves' Duodenum and Abdominal Rumen

With this study, we aimed to evaluate the effect of two multicomponent feed additives given to animals from 10 to 70 d with milk replacer on the production parameters of reared calves: serum selenium level and histology of duodenum and rumen. The first additive was based on nanosilica (3000 mg) containing pancreatic enzymes (protease (18 mg), lipase (45 mg)), a mixture of fat-coated organic acids (2000 mg) (fumaric, malic, citric, and sorbic acids), and sodium butyrate (10,000 mg) (nanosilica/E/OA/SB), whereas the second was based on the mycelium of L. edodes (7 g) enriched in selenium (0.058 mg/g d.w.) (L. edodes/Se). The study was conducted on 18 male crossbred Holstein dairy calves from birth to 70 days of age, which were randomly assigned to control and experimental groups (six animals in each). From each group, three animals were sacrificed at 70 days of age, and histological analysis of the digestive tract (abdominal rumen and small intestine) was performed. It was observed that the additives used did not have any effect on growth performance and hematological or biochemical parameters. However, higher levels of selenium were found in serum in the calves fed with modified L. edodes mycelium on days 35 and 70 (44.33 and 51.33 µg/L in the control group and 132 and 93 µg/L in the L. edodes/Se group, respectively; p < 0.001). Moreover, we noticed lower average daily milk replacer intake at 35−42 d, which increased significantly from 42 to 70 d in the animals receiving L. edodes/Se.

Wild mushrooms from Ilgaz Mountain National Park (Western Black Sea, Turkey): element concentrations and their health risk assessment

The purpose of this study was to determine Fe, Cd, Cr, Se, P, Cu, Mn, Zn, Al, Ca, Mg, and K contents of some edible (Chlorophyllum rhacodes, Clavariadelphus truncatus, Clitocybe nebularis, Hydnum repandum, Hygrophorus pudorinus, Infundibulicybe gibba, Lactarius deliciosus, L. piperatus, L. salmonicolor, Macrolepiota mastoidea, Russula grata, Suillus granulatus, and Tricholoma imbricatum), inedible (Amanita pantherina, Geastrum triplex, Gloeophyllum sepiarium, Hypholoma fasciculare, Phellinus vorax, Pholiota limonella, Russula anthracina, and Tapinella atrotomentosa), and poisonous mushroom species (Amanita pantherina and Hypholoma fasciculare) collected from Ilgaz Mountain National Park (Western Black Sea, Turkey). The element contents of the mushrooms were determined to be 18.0-1239.1, 0.2-4.6, 0.1-3.4, 0.2-3.2, 1.0-8.9, 3.3-59.9, 3.7-220.4, 21.3-154.1, 6.4-754.3, 15.8-17,473.0, 413.0-5943.0, and 2803.0-24,490.0 mg·kg^-1, respectively. In addition to metal contents, the daily intakes of metal (DIM) and Health Risk Index (HRI) values of edible mushrooms were also calculated. Both DIM and HRI values of mushroom species except L. salmanicolor, M. mastoidea, and R. grata were within the legal limits. However, it was determined that the Fe content of L. salmanicolor and M. mastoidea and Cd content of R. grata were above the legal limits.

Detrimental and essential elements in fruiting bodies of wild-growing fungi Coprinus comatus, Flammulina velutipes, and Armillaria ostoyae

Edible medicinal wild-growing fungi Coprinus comatus, Flammulina velutipes, and Armillaria ostoyae were analyzed with regard to the contents of 21 elements in their fruiting bodies. The samples were collected from selected sites in South Bohemia, the Czech Republic. C. comatus concentrated Ag, Cd, Cu, Se, and Rb with bioconcentration factors of 12, 2.5, 2.3, 1.8, and 1.1, respectively. High contents (all values expressed in mg kg^-1 dry matter) of Al (260), Ca (480), Cu (61), Fe (340), Mg (1400), and Zn (86) were determined for this species. F. velutipes was characterized with markedly high contents of Ca (360), Fe (110), Mg (1200), Mn (26), and Zn (98), respectively. A considerably high content of Ag (5.6) was revealed for A. ostoyae. High contents of Ca (150), Cu (28), Fe (190), Mg (1100), Mn (30), and Zn (40) were determined in fruiting bodies of this species as well. The data concerning the detrimental elements in fruiting bodies of studied fungi indicate no considerably negative effect on human health if they are consumed as a delicacy or used in alternative medicine.

Nutritional and Other Trace Elements and Their Associations in Raw King Bolete Mushrooms, Boletus edulis

The occurrence and associations of Ag, As, Ba, Bi, Cd, Co, Cu, Cs, Hg, Ni, Pb, Rb, Sb, Sr, Tl, U, V, W, and Zn, including data that have not been previously reported on Be, Hf, In, Li, Mo, Nb, Sn, Ta, Th, Ti and Zr, and the sum of (14) rare earth elements (ƩREE), were studied in a spatially diverse collection of the B. edulis caps, stipes, and whole fruiting bodies using a validated procedure with measurement by quadrupole ICP-MS. Toxic Cd and Pb were in B. edulis at concentrations below limits set by the European Union in regulations for raw cultivated mushrooms, while Ag, As, Hg, Sb, Tl, and U, which are not regulated, were at relatively low or typical levels as is usually found in mushrooms from an unpolluted area. The elements Be, Bi, Ga, Ge, Hf, In, Nb, Ta, Th, and W, and also ƩREEs, were found at relatively low concentrations in B. edulis, i.e., with levels from below 0.1 to below 0.01 mg kg-1 dw, and for Ʃ14 REEs, the median was 0.31 mg kg-1 dw. The composite samples of caps showed Ag, Cd, Cu, Cs, Ga, Ge, Hg, Mo, Ni, Rb, Sb, Ti, and Zn at higher concentrations than stipes, while Ba, Co, Hf, Sr, Tl, and Zr were found at higher concentrations in stipes than caps (p < 0.05). Mushrooms were characterized by a low coefficient of variation (CV) of below 20%, between sites for concentrations of As, Cu, Ge, Hg, Ni, V, and Zn, while substantial differences (CV > 100%) were found for Ba, Bi, Co, Hf, Zr, and ƩREEs, and an intermediate variation was found for Sr, W, and U. Principal component analysis performed on mushrooms allowed differentiation with respect to 13 collection sites and separation of a consignment that was specifically contaminated, possibly due to a legacy pollution, with significantly higher levels of Ba, Co, Ga, Li, Nb, Ni, Sr, Th, Ti, Y, Zr, and ƩREEs, and another due to possible recent pollution (Pb-gasoline and also Ni); two due to geological contamination because of the Bi, In, Sc, Sb, Sn, Ta, V and W; and one more, the Sudety Mts. site, which was considered as "geogenic/anthropogenic" due to Ag, As, Be, Cd, Cs, Ni, Pb, Rb, Tl, and U.

Detrimental and essential elements in fruiting bodies of mushrooms with ecological relationship to birch (Betula sp.) collected in the Bohemian Forest, the Czech Republic

Four macrofungi species with ecological relationship to birch (Betula sp.) were analyzed with regard to the content of 21 detrimental and essential elements in their fruiting bodies. Two of the species (Leccinum scabrum and Leccinum versipelle) were mycorrhizal forming edible fruiting bodies while the others (Fomitopsis betulina and Inonotus obliquus) parasitic used in alternative medicine. The samples were collected near the town of Vimperk in the Bohemian Forest, the Czech Republic. L. scabrum accumulated Ag, Rb, Cd, Cs, Se, Cu, and Zn with bioconcentration factors of 22, 5.5, 4.7, 3.2, 2.0, 1.7, and 1.4, respectively. Similar trend in bioconcentration was revealed for L. versipelle with bioconcentration factors of 28, 5.2, 2.4, 1.9, 1.6, and 1.6 determined for Ag, Rb, Cu, Se, Zn, and Cd, respectively. Considerably high contents of Ca (400 ± 190 mg kg^-1 dry matter), Fe (110 ± 30), Mg (1100 ± 300), and Zn (220 ± 90) were found in F. betulina. Similarly, high contents of Ca (1000 ± 700 mg kg^-1 dry matter), Fe (110 ± 30), Mg (2000 ± 1100), Mn (410 ± 270), Rb (160 ± 60), and Zn (140 ± 70) were determined for I. obliquus. The different lifestyles (mycorrhizal vs. parasitic) were reflected in 13 significant differences of element contents.

Mercury in Macrolepiota procera (Scop.) Singer and Its Underlying Substrate-Environmental and Health Risks Assessment

Wild-growing edible mushrooms are valuable food with a high content of proteins, fibers, antioxidants, and they are characterized by their specific taste and flavor. However, from an ecotoxicological point of view, they are a risk commodity because of their extremely high bioaccumulative capacity to accumulate the risk elements and contaminants from the environment. In the present study, we examined mercury (Hg) contamination in 230 fruiting bodies of Macrolepiota procera (Scop.) Singer and 230 soil/substrate samples, which were collected in foraging seasons 2015-2019 from 22 different locations in Slovakia. Total mercury content was determined by cold-vapor AAS analyzer AMA 254. The level of contamination and environmental risks were assessed by contamination factor (Cf), index of geoaccumulation (Igeo), and potential environmental risk index (PER). Bioaccumulation factor (BAF) was calculated for individual anatomical parts of M. procera. Mercury content in the soil/substrate samples varied between 0.02 and 0.89 mg kg-1 DW, and in mushroom samples between 0.03 and 2.83 mg kg-1 DW (stems), and between 0.04 and 6.29 mg kg-1 DW (caps). The obtained results were compared with the provisional tolerable weekly intake for Hg defined by WHO to determine a health risk resulting from regular and long-term consumption of M. procera.

Pleurotus spp. Mycelia Enriched in Magnesium and Zinc Salts as a Potential Functional Food

Worldwide, mushrooms belonging to the Pleurotus spp. such as P. citrinopileatus, P. djamor, and P. pulmonarius are highly valued not only for their taste and aroma but also for their health-promoting properties. These species are rich in bioelements, vitamins, and above all, compounds that exhibit immunostimulatory activity. Therefore, in this study, we aimed to determine the effect of the supplementation of culture media using inorganic Mg and Zn salts. This is the first study to establish the bioavailability of the selected elements (Mg and Zn) and anions (Cl⁻, SO₄²⁻) from the enriched biomass by means of the extraction of lyophilized mycelium into artificial digestive juices. The following salts were added to the liquid Oddoux medium: ZnSO₄·7H₂O, ZnCl₂, MgSO₄·7H₂O or MgCl₂·6H₂O. The bioelements, anions and organic compounds in the obtained biomass were determined. The addition of Zn and Mg salts to the media increased the production of biomass by 30% and increased the bioaccumulation of the inorganic salts. Maintaining in vitro cultures under optimized and controlled conditions produced mycelium with a better composition and health properties than otherwise. Such enriched biomass may be classified as potential functional foods, aiding in overcoming deficiencies of elements and organic compounds with biological activity in humans.

Metal concentration and health risk assessment of fifteen wild mushrooms collected from the Ankara University Campus (Turkey)

The aim of this study is to analyze Fe, Mn, Cu, Zn, Co, Cd, Pb, and Ni contents of Cyclocybe cylindracea, Armillaria mellea, Bjerkandera adusta, Rheubarbariboletus armeniacus, Coprinellus disseminatus, C. micaceus, C. comatus, Inonotus hispidus, Lepista nuda, Leucoagaricus leucothites, Pleurotus ostreatus, Cerioporus squamosus, Schizophyllum commune, Scleroderma verrucosum, and Trametes trogii collected from the Ankara University Besevler 10th Year Campus (Turkey), an area where human settlement and traffic are intense. In addition to the elemental analysis, the daily intake of metal (DIM) and health risk index (HRI) values of the edible ones were also calculated. Fe, Mn, Cu, Zn, Co, Cd, Pb, and Ni concentrations of the samples were found to be 112.0-5079.0, 3.0-124.0, 4.0-77.0, 2.0-196.0, 0.18-2.98, 0.18-5.3, 0.04-10.98, and 0.22-8.23 mg/kg dry weight, respectively. As a result of DIM and HRI analysis, C. cylindracea, L. nuda, and C. squamosus were found to be within the reference dose limits determined by competent authorities and can be safely consumed in terms of all metals studied. However, the Cd, Co, and Fe contents of C. micaceus were found to be above 1.0 (1.06, 4.25, and 7.06, respectively). In addition, it has been found that A. mellea, R. armeniacus, C. comatus, L. leucothites, and P. ostreatus are toxic in terms of Cd/Co, Fe/Pb, Co/Fe, Cd, and Fe contents, respectively. As the area in question is a traffic intensive area, it has been concluded that the emissions of the vehicles should be controlled in terms of legal limits and that the consumption of some mushrooms in this region should not be preferred until necessary measures are taken.

Metal concentration and health risk assessment of wild mushrooms collected from the Black Sea region of Turkey

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.

Trace elements and C and N isotope composition in two mushroom species from a mine-spill contaminated site

Fungi play a key role in the functioning of soil in terrestrial ecosystems, and in particular in the remediation of degraded soils. The contribution of fungi to carbon and nutrient cycles, along with their capability to mobilise soil trace elements, is well-known. However, the importance of life history strategy for these functions has not yet been thoroughly studied. This study explored the soil-fungi relationship of two wild edible fungi, the ectomycorrhizal Laccaria laccata and the saprotroph Volvopluteus gloiocephalus. Fruiting bodies and surrounding soils in a mine-spill contaminated area were analysed. Isotope analyses revealed Laccaria laccata fruiting bodies were 15N-enriched when compared to Volvopluteus gloiocephalus, likely due to the transfer of 15N-depleted compounds to their host plant. Moreover, Laccaria laccata fruiting bodies δ13C values were closer to host plant values than surrounding soil, while Volvopluteus gloiocephalus matched the δ13C composition to that of the soil. Fungal species presented high bioaccumulation and concentrations of Cd and Cu in their fruiting bodies. Human consumption of these fruiting bodies may represent a toxicological risk due to their elevated Cd concentrations.

Wild edible mushrooms from Mediterranean region: Metal concentrations and health risk assessment

Worldwide, among the forest products, wild edible mushrooms constitute an important part because they represent food source as well as income source for many local communities. Thirteen essential elements (Ca, Co, Cr, Cu, Fe, K, Mg, Mn and Zn) and non-essential elements (Al, Cd, Ni and Pb) in wild edible mushrooms from six families (Agaricaceae, Auriculariaceae, Hygrophoraceae, Russulaceae, Suillaceae, and Tricholomataceae) originated from the Mediterranean region of Turkey were determined. Major element was K, followed by Ca, Mg, Fe and Al. Concentrations of detected elements were in the range from 0.05 mg/kg (Co) to 141,400 mg/kg (K). Health Risk Index for elements that may pose health problems indicated that safe limits were exceeded for Cd (L. nuda, L. decastes, M. exscissa, R. albonigra, R. delica and T. terreum), Ni (A. auricula-judae and S. luteus) as well as for Fe (A. auricula-judae and M. paedida). In Arpacık village and Deliosman village areas the highest number of wild edible mushrooms with HRI>1 was collected. The differences and similarities between mushroom species were established by Principal Component Analysis and Hierarchical Component Analysis.

The three-year monitoring of 18 elements in five edible mushroom species collected from an old orchard

The content of Al, As, Be, Cd, Ca, Cr, Co, Cu, Fe, Pb, Li, Mg, Mn, Ni, Rb, Se, Sr, and Zn in fruiting bodies of edible mushrooms Calocybe gambosa, Entoloma clypeatum, Entoloma saepium, Xerocomellus chrysenteron, and Amanita rubescens growing in an orchard planted with fruit trees and situated close to a high-grown forest was studied during years 2016-2018. A. rubescens showed the highest potential of the element accumulation with bioconcentration factors of 48.5, 16.2, 7.80, 6.53, 1.75, and 1.68 obtained for Rb, Cd, Cu, Zn, Sr, and Mg, respectively. Both Entoloma species accumulated the elements similarly with bioconcentration factors >1.0 obtained for Rb, Cu, Cd, and Mg. Bioconcentration factors <0.05 were obtained for Al, Cr, Fe, and Pb in all studied species. The contents of beryllium (<0.1 mg/kg dry matter) were always the lowest among the studied elements. The contents of some elements of studied mushroom species significantly fluctuated over the years. Despite the fact that some studied elements (As, Be, Cd, Pb, Ni) are considerably toxic for humans, the pronounced effect on health is not expected if the studied mushroom species are consumed occasionally and do not represent the main component of the diet.

Copper, Manganese, Selenium and Zinc in Wild-Growing Edible Mushrooms from the Eastern Territory of "Green Lungs of Poland": Nutritional and Toxicological Implications

The aims of this study were to determine Cu, Mn, Se, and Zn content in wild mushrooms collected from unpolluted areas of the eastern Green Lungs of Poland (GLP) territory, to compare them to some popular species of cultivated mushrooms, evaluate mushroom contribution to the daily intake of the studied bioelements, and to determine their possible toxic effect resulting from potentially excessive mushroom consumption from areas recognized as ecologically uncontaminated. Bioelements were determined in 21 species of edible mushrooms: eighteen species of wild mushrooms and three species of popular cultivated mushrooms. The mean Cu, Mn, Se, and Zn content (in µg/g, dry mass DM) ranged from 10.6–123.1, 12.2–41, 0.13–13.3, and 68.3–184, respectively. A comparison with recommended dietary allowance (RDA) for Cu, Se, and Zn as well as adequate intake (AI) for Mn demonstrated that a 100 g fresh mass (FM) portion of mushroom species with the highest content of a given element can meet the demand for Cu, Mn, Se and Zn at 203%, 14–17%, 211%, and 16–22%, respectively. A comparison of the content of the examined bioelements contained in one portion of mushrooms (100 g FM) against the toxicological intake limits for different chemical elements with the provisional maximum tolerable daily intake (PMTDI) and upper intake level (UL) showed no risk of toxicity for the evaluated mushroom species.

Variation of heavy metal contamination between mushroom species in the Copperbelt province, Zambia: are the people at risk?

BACKGROUND

Heavy metal contamination in mushrooms and the associated health risk are unknown in Zambia. We studied seven heavy metals and 23 mushroom species and interviewed 400 people.

RESULTS

Mushrooms were found to contain substantial concentrations of Cu (894.4 ± 267.9 µg g^-1 ) and Fe (998.4 ± 454.0 µg g^-1 ). Significant differences in transfer factors of metals occurred between mushroom species (F_11,66  = 5.36, P < 0.001). The most efficient were L. kabansus (for Zn and Ni), A. miomboensis (for Cu and Fe) and T. clypeatus (for Mn, Pb and Co). These species were also among the most preferred mushrooms for consumption based on the interviews conducted. Although 60% of the mushrooms observed were edible, only 20% were frequently consumed during the mushroom season. High positive correlations observed between soils and mushrooms suggest that contamination in mushrooms increases with soil pollution. The estimated daily intake of metals and the target hazard quotient through mushroom consumption were found to be significantly influenced by mushroom species (F_11,66  = 38.8, P < 0.001) suggesting that the level of exposure to heavy metals depends on the species of mushroom consumed.

CONCLUSIONS

The study has revealed that heavy metal concentrations in mushrooms exceed permissible limits and vary between species. Transfer efficiency also varies between mushroom species and contamination in mushrooms increases with soil pollution. The fact that concentrations of metals in soil were significantly high, the risk of exposure through mushroom consumption and possibly soil ingestion is even higher. © 2019 Society of Chemical Industry.

Effects of corn stalk cultivation substrate on the growth of the slippery mushroom (Pholiota microspora)

Corn stalks are a major source of agricultural waste in China that have the potential for more efficient utilisation. In this study, we designed substrate formulas with different proportions of corn stalks to cultivate Pholiota microspora. The substrate formula for P. microspora cultivation that could partially or completely replace sawdust with corn stalks was selected through the analysis of mycelial growth rates, fruiting body traits, yield, biological efficiency, nutrients, and mineral composition. Our results showed that the substrate formula T2 (38% wood chips and 38% corn stalks) resulted in the highest yield of 275.66 ± 2.87 g per bag, which was 6.60% higher than that of formula CK, and the highest biological efficiency of 90.75 ± 0.04%, which was 4.58% higher than that of CK, with no significant differences from CK in terms of fruiting body traits, nutrients, or mineral composition. The substrate formula T1 (19% corn stalks) led to mushroom yields with the highest mineral and amino acid contents and was thus more suitable for the cultivation of medicinal P. microspora. Therefore, substrates comprising a mixture of corn stalks and sawdust can be used as a novel, inexpensive, and high-yield alternative for the cultivation of P. microspora.

Selenium Analysis and Speciation in Dietary Supplements Based on Next-Generation Selenium Ingredients

Selenium is essential for humans and the deficit of Se requires supplementation. In addition to traditional forms such as Se salts, amino acids, or selenium-enriched yeast supplements, next-generation selenium supplements, with lower risk for excess supplementation, are emerging. These are based on selenium forms with lower toxicity, higher bioavailability, and controlled release, such as zerovalent selenium nanoparticles (SeNPs) and selenized polysaccharides (SPs). This article aims to focus on the existing analytical systems for the next-generation Se dietary supplement, providing, at the same time, an overview of the analytical methods available for the traditional forms. The next-generation dietary supplements are evaluated in comparison with the conventional/traditional ones, as well as the analysis and speciation methods that are suitable to reveal which Se forms and species are present in a dietary supplement. Knowledge gaps and further research potential in this field are highlighted. The review indicates that the methods of analysis of next-generation selenium supplements should include a step related to chemical species separation. Such a step would allow a proper characterization of the selenium forms/species, including molecular mass/dimension, and substantiates the marketing claims related to the main advantages of these new selenium ingredients.

Determination of mineral contents of wild Boletus edulis mushroom and its edible safety assessment

This study aimed to determine the contents of main mineral elements of wild Boletus edulis and to assess its edible safety, which may provide scientific evidence for the utilization of this species. Fourteen mineral contents (Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Sr, V and Zn) in the caps and stipes of B. edulis as well as the corresponding surface soils collected from nine different geographic regions in Yunnan Province, southwest China were determined. The analyses were performed using inductively coupled plasma atomic emission spectrometer (ICP-AES) after microwave digestion. Measurement data were analyzed using variance and Pearson correlation analysis. Edible safety was evaluated according to the provisionally tolerable weekly intake (PTWI) of heavy metals recommended by United Nations Food and Agriculture Organization and World Health Organization (FAO/WHO). Mineral contents were significantly different with the variance of collection areas. B. edulis showed relative abundant contents of Ca, Fe, Mg and Na, followed by Ba, Cr, Cu, Mn and Zn, and the elements with the lower content less were Cd, Co, Ni, Sr and V. The elements accumulation differed significantly in caps and stipes. Among them, Cd and Zn were bioconcentrated (BCF > 1) while others were bioexcluded (BCF < 1). The mineral contents in B. edulis and its surface soil were positively related, indicating that the elements accumulation level was related to soil background. In addition, from the perspective of food safety, if an adult (60 kg) eats 300 g fresh B. edulis per week, the intake of Cd in most of tested mushrooms were lower than PTWI value whereas the Cd intakes in some other samples were higher than this standard. The results indicated that the main mineral contents in B. edulis were significantly different with respect to geographical distribution, and the Cd intake in a few of regions was higher than the acceptable intakes with a potential risk.

Mercury in forest mushrooms and topsoil from the Yunnan highlands and the subalpine region of the Minya Konka summit in the Eastern Tibetan Plateau

This study aimed to investigate and discuss the occurrence and accumulation of mercury in the fruiting bodies of wild-growing fungi (Macromycetes) collected from montane forests in two regions of southwestern China with differences in soil geochemistry, climate and geographical conditions. Fungal mycelia in soils of the subalpine region of the Minya Konka (Gongga Mountain) in Sichuan and in the highlands of Yunnan efficiently accumulated mercury in fruiting bodies (mushrooms). The examined sites in Yunnan with highly mineralized red and yellow soils showed Hg contents ranging from 0.066 to 0.28 mg kg^-1 dry biomass (db) which is roughly similar to the results obtained for samples collected from sites with dark soils relatively rich in organic matter from a remote, the subalpine region of Minya Konka. Due to the remoteness of the subalpine section of Minya Konka, as well as its elevation and climate, airborne mercury from long-range transport could be deposited preferentially on the topsoil and the Hg levels determined in soil samples taken beneath the fruiting bodies were up to 0.48 mg kg^-1 dry matter. In Yunnan, with polymetallic soils (Circum-Pacific Mercuriferous Belt), Amanita mushrooms showed mercury in caps of fruiting bodies of up to 7.3 mg kg^-1 dry biomass. Geogenic Hg from the mercuriferous belt seems to be the overriding source of mercury accumulated in mushrooms foraged in the regions of Yunnan, while long-range atmospheric transport and subsequent deposition are the mercury sources for specimens foraged in the region of Minya Konka.

Determination of 210Po and 210Pb in red-capped scaber (Leccinum aurantiacum): bioconcentration and possible related dose assessment

The paper presents the studies on ²¹⁰Po and ²¹⁰Pb activity determination in red-capped scaber (Leccinum aurantiacum (Bulliard) Gray) collected in northern Poland. The aims of the studies were to determine ²¹⁰Po and ²¹⁰Pb content in analyzed mushrooms, evaluate the bioconcentration levels, and estimate possible related annual effective radiation dose to mushrooms consumers. The activities of ²¹⁰Po and ²¹⁰Pb in red-capped scaber were un-uniform and depended on sampling sites. But ²¹⁰Po and ²¹⁰Pb activity concentrations did not reflect their concentrations in topsoil. The results showed that the consumption of analyzed mushrooms should not increase significantly the total effective radiation dose from ²¹⁰Po and ²¹⁰Pb decay.

Arsenic, Lead, and Cadmium in U.S. Mushrooms and Substrate in Relation to Dietary Exposure

Wild mushrooms can absorb high quantities of metal(loid)s, yet the concentration, speciation, and localization of As, Pb, and Cd in cultivated mushrooms, particularly in the United States, are unresolved. We collected 40 samples of 12 types of raw mushrooms from 2 geographic locations that produce the majority of marketable U.S. mushrooms and analyzed the total As, Pb, and Cd content, the speciation and localization of As in select samples, and assessed the metal sources and substrate-to-fruit transfer at one representative farm. Cremini mushrooms contained significantly higher total As concentrations than Shiitake and localized the As differently; while As in Cremini was distributed throughout the fruiting body, it was localized to the hymenophore region in Shiitake. Cd was significantly higher in Royal Trumpet than in White Button, Cremini, and Portobello, while no difference was observed in Pb levels among the mushrooms. Concentrations of As, Pb, and Cd were less than 1 μg g(-1) d.w. in all mushroom samples, and the overall risk of As, Cd, and Pb intake from mushroom consumption is low in the U.S. However, higher percentages of tolerable intake levels are observed when calculating risk based on single serving-sizes or when substrate contains elevated levels of metal(loid)s.

Australian atmospheric lead deposition reconstructed using lead concentrations and isotopic compositions of archival lichen and fungi

Lead concentrations and their isotopic compositions were measured in lichen genera Cladonia and Usnea and fungi genus Trametes from the Greater Sydney region (New South Wales, Australia) that had been collected and archived over the past 120 years. The median lead contents were elevated in lichens and fungi prior to the introduction of leaded petrol (Cladonia 12.5 mg/kg; Usnea 15.6 mg/kg; Trametes 1.85 mg/kg) corresponding to early industrial development. During the use of leaded petrol for automobiles in Australia from 1932 to 2002, total median lead concentrations rose: Cladonia 18.8 mg/kg; Usnea 21.5 mg/kg; Trametes 4.3 mg/kg. Following the cessation of leaded petrol use, median total lead concentrations decreased sharply in the 2000s: Cladonia 4.8 mg/kg; Usnea 1.7 mg/kg. The lichen and fungi isotopic compositions reveal a significant decrease in (206)Pb/(207)Pb values from the end of 19th century to the 1970s. The following decades were characterised by lower allowable levels of lead additive in fuel and the introduction of unleaded petrol in 1985. The environmental response to these regulatory changes was that lichen and fungi (206)Pb/(207)Pb values increased, particularly from 1995 onwards. Although the lead isotope ratios of lichens continued to increase in the 2000s they do not return to pre-leaded petrol values. This demonstrates that historic leaded petrol emissions, inter alia other sources, remain a persistent source of anthropogenic contamination in the Greater Sydney region.

Evaluation of Mercury Contamination in Fungi Boletus Species from Latosols, Lateritic Red Earths, and Red and Yellow Earths in the Circum-Pacific Mercuriferous Belt of Southwestern China

For the first time, highly elevated levels of mercury (Hg) have been documented for several species of the edible Fungi genus Boletus growing in latosols, lateritic red earths, and red and yellow earths from the Yunnan province of China. Analysis of Hg concentrations in the genus suggests that geogenic Hg is the dominant source of Hg in the fungi, whereas anthropogenic sources accumulate largely in the organic layer of the forest soil horizon. Among the 21 species studied from 32 locations across Yunnan and 2 places in Sichuan Province, the Hg was found at elevated level in all samples from Yunnan but not in the samples from Sichuan, which is located outside the mercuriferous belt. Particularly abundant in Hg were the caps of fruiting bodies of Boletus aereus (up to 13 mg kg^-1 dry matter), Boletus bicolor (up to 5.5 mg kg^-1 dry matter), Boletus edulis (up to 22 mg kg^-1 dry matter), Boletus luridus (up to 11 mg kg^-1 dry matter), Boletus magnificus (up to 13 mg kg^-1 dry matter), Boletus obscureumbrinus (up to 9.4 mg kg^-1 dry matter), Boletus purpureus (up to 16 mg kg^-1 dry matter), Boletus sinicus (up to 6.8 mg kg^-1 dry matter), Boletus speciosus (up to 4.9mg kg^-1 dry matter), Boletus tomentipes (up to 13 mg kg^-1 dry matter), and Boletus umbriniporus (up to 4.9 mg kg^-1 dry matter). Soil samples of the 0–10 cm topsoil layer from the widely distributed locations had mercury levels ranging between 0.034 to 3.4 mg kg^-1 dry matter. In Yunnan, both the soil parent rock and fruiting bodies of Boletus spp. were enriched in Hg, whereas the same species from Sichuan, located outside the mercuriferous belt, had low Hg concentrations, suggesting that the Hg in the Yunnan samples is mainly from geogenic sources rather than anthropogenic sources. However, the contribution of anthropogenically-derived Hg sequestered within soils of Yunnan has not been quantified, so more future research is required. Our results suggest that high rates of consumption of Boletus spp. from Yunnan can deliver relatively high doses of Hg to consumers, but that rates can differ widely because of large variability in mercury concentrations between species and locations.

Variations in Element Levels Accumulated in Different Parts ofBoletus edulisCollected from Central Yunnan Province, China

ICP-AES and microwave assisted digestion were applied to determine P, Mg, Ca, Zn, Na, Cu, Ba, Ni, V, Cd, Sr, Co, and Li in the caps and stipes ofBoletus eduliscollected from six spatially distant sites in Yunnan province, China. Fruiting bodies of King Bolete are abundant in P, Mg, Ca, Zn, Cu, and Na, followed by Ba, Cd, Ni, V, Li, Sr, and Co. Contents of P, Mg, Zn, and Cu are more abundant in caps than in stipes of King Bolete. However, elements such as Na, Ba, Cd, Ni, V, Li, Sr, and Co prefer to accumulate in stipes of mushrooms from Yaoan, Chuxiong. The results of this study indicate that spatial variations of elements between caps and stipes are mainly related to different bedrock soil geochemistry and enrichment capability for various elements.

Macro and trace elements in Common Chanterelle (Cantharellus cibarius) mushroom from the European background areas in Poland: Composition, accumulation, dietary exposure and data review for species

This paper gives an up-to-date information on accumulation, occurrence, intake and possible health risks associated with noxious metallic elements (Ag, Cd, Hg, Pb) among mineral constituents (Ag, Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sr and Zn) contained in Common Chanterelle (Cantharellus cibarius) mushrooms, a species subjected to a broad use within the domestic market of Poland and widely exported abroad, and presents a short review of data from the available literature. The tasty values of C. cibarius seem to be more rated than the essential minerals contained in its flesh and nominally taken with 1,000 g of fresh fruiting bodies eaten per capita annually, while the contents of toxic or potentially toxic metals, such as Cd, Pb, Hg and Ag, are much below the tolerance limits.

Mercury in Hazel Bolete Leccinum griseum and soil substratum: Distribution, bioconcentration and dietary exposure

This study aimed to examine the accumulation and distribution of total mercury (Hg) in fruiting bodies of edible wild-grown mushroom Hazel Bolete Leccinum griseum (Quél.) Singer, collected from six spatially distantly distributed places across Poland and to assess the probable dietary intake of the element by consumers. Mercury content of fungal and soil samples were determined by cold-vapour atomic absorption spectroscopy (CV-AAS) with a direct sample thermal decomposition coupled with gold wool trap of Hg and its further desorption and quantitative measurement at the wavelength of 296 nm. The median values of Hg content in caps of L. griseum collected from less-contaminated places (< 0.10 mg Hg kg(-1) dry matter in upper 0-10 cm layer of soil substratum) were from 0.23 mg kg(-1) dm to 0.43 mg kg(-1) dm. And for more contaminated topsoil (0.15 mg Hg kg(-1) dry matter), the median in caps was about 1.5 mg kg(-1) dry matter. The mushroom L. griseum has potential to accumulate Hg in fruiting bodies, while quantities of this element noted in consignments of this species originating from the forests with typical background values of Hg in topsoil are low. In the light of the published value of PTWI for Hg consumption of fruiting bodies of L. griseus emerged in forests of Poland is without health risk for consumers. Information on total mercury and methylmercury in Fungi of the genus Leccinum is also described briefly.

Do differences in chemical composition of stem and cap of Amanita muscaria fruiting bodies correlate with topsoil type?

Fly agaric (Amanita muscaria) was investigated using a ¹H NMR-based metabolomics approach. The caps and stems were studied separately, revealing different metabolic compositions. Additionally, multivariate data analyses of the fungal basidiomata and the type of soil were performed. Compared to the stems, A. muscaria caps exhibited higher concentrations of isoleucine, leucine, valine, alanine, aspartate, asparagine, threonine, lipids (mainly free fatty acids), choline, glycerophosphocholine (GPC), acetate, adenosine, uridine, 4-aminobutyrate, 6-hydroxynicotinate, quinolinate, UDP-carbohydrate and glycerol. Conversely, they exhibited lower concentrations of formate, fumarate, trehalose, α- and β-glucose. Six metabolites, malate, succinate, gluconate, N-acetylated compounds (NAC), tyrosine and phenylalanine, were detected in whole A. muscaria fruiting bodies but did not show significant differences in their levels between caps and stems (P value>0.05 and/or OPLS-DA loading correlation coefficient <0.4). This methodology allowed for the differentiation between the fruiting bodies of A. muscaria from mineral and mineral-organic topsoil. Moreover, the metabolomic approach and multivariate tools enabled to ascribe the basidiomata of fly agaric to the type of topsoil. Obtained results revealed that stems metabolome is more dependent on the topsoil type than caps. The correlation between metabolites and topsoil contents together with its properties exhibited mutual dependences.

Contamination of wild-grown edible mushrooms by heavy metals in a former mercury-mining area

The aim of this study was to evaluate the contamination of six edible wild species of mushrooms (Boletus pulverulentus, Cantharellus cibarius, Lactarius quietus, Macrolepiota procera, Russula xerampelina and Suillus grevillei) by heavy metals (Hg, Cd, Pb, Zn, Cu, Ni, Cr, Co, Mn and Fe). Mushroom samples were collected from sites contaminated by emissions from mining and processing of polymetallic ores in operation during the period 1969-1993 in Rudňany, southeast Slovakia. The four study sites spanned up to a 5-km distance from the emission source. The collected mushroom samples were analyzed using Flame Atomic Absorption Spectrophotometry and/or Flame Atomic Absorption Spectrophotometry with graphite furnace. Mercury, Cd and, in some samples, also Pb present the highest risks in terms of contamination of the food chain following subsequent consumption. The content of two metals in the dry matter (dm) of the mushrooms exceeded the limits set by the European Union (EU; Cd: 0.5 mg/kg dm, Pb: 1.0 mg/kg dm). The highest mean contents of the eight metals recorded for S. grevillei were 52.2, 2.15, 107, 104, 2.27, 2.49, 81.6 and 434 mg/kg dm for Hg, Pb, Zn, Cu, Ni, Cr, Mn and Fe, respectively. The highest content of Cd was recorded in M. procera (3.05 mg/kg dm) and that of Co in L. quietus (0.90 mg/kg dm). The calculated weekly intake for Hg, Pb and Cd shows that regular consumption of mushrooms from the studied area poses risks to human health.