Macro and trace mineral constituents and radionuclides in mushrooms: health benefits and risks

Selected detrimental and essential elements in fruiting bodies of culinary and toxic medicinal macroscopic fungi growing in the Bohemian Forest, the Czech Republic

Selected wild-growing edible fungi (Boletus edulis, Neoboletus luridiformis, Cantharellus cibarius, Macrolepiota procera, Amanita rubescens, Russula virescens, Lycoperdon perlatum, and Flammulina velutipes) along with the poisonous medicinal species Amanita muscaria were collected from five sites in the Bohemian Forest, the Czech Republic and analyzed regarding the contents of 19 elements (Ag, Al, As, Be, Ca, Cd, Co, Cr, Cu, Fe, Li, Mg, Mn, Ni, Pb, Rb, Se, Tl, and Zn) in their fruiting bodies. The contents of the elements as well as bioconcentration factors (ratios of the element content in dry matter of the mushroom to the content in the soil; BCF) were significantly species dependent. In general, the analysis revealed the most intensive accumulation of Cd, Rb, Ag, Cu, Se, and Zn in the studied mushrooms. B. edulis accumulated Ag, Se, Cd, Rb, Cu, and Zn with average BCF of 31, 25, 18, 13, 3.9, and 2.6, respectively. On the other hand, A. rubescens accumulated Cd, Rb, Ag, Cu, Zn, and As (BCF of 41, 27, 4.8, 3.3, 2.1, and 1.4). The data concerning the detrimental elements in sporocarps of edible mushrooms indicate no negative effect on human health if the fungi are consumed occasionally or as a delicacy.

Metal Content in Caps and Stalks of Edible Mushrooms: Health Benefits and Risk Evaluation

Mushrooms are a good source of protein and phenolic compounds which provides health benefits for humans. The purpose of this study was to compare the content of eight metals, protein, and total phenolics (TPC) of 5 different species (Agaricus bisporus-white and brown mushrooms, Agaricus cupreobrunneus, Auricularia cornea, Hypsizgus tesselatus, and Pleurotus eryngii species-complex) of edible mushrooms available on the Romanian market. Agaricus bisporus and Agaricus cupreobrunneus were purchased and cultivated in Romania and the other species were cultivated in other countries (Turkey and China). The metal content determined by graphite atomic absorption spectrometry (GTAAS) varied in the order Cu > Pb > Ni > Fe > Cr > Mn > Co > Cd. Almost all the samples contained a greater quantity of metals in the stalk than in the cap. In addition, the levels of toxic metals were low. The protein content of analyzed samples ranged from 0.0926 to 0.2743%, the highest value being observed in Pleurotus eryngii species-complex mushroom. TPC of extracts increased over time but there was a variability in the concentration for each mushroom species (0.25-12.25 mg GAE/g). The investigated mushroom species possess no health risk and may be potential nutritional supplements for human diets due to their phenolic compounds, protein, and mineral content.

Rare earth contamination of edible vegetation: Ce, La, and summed REE in fungi

The increasing and diversified use of rare earth elements (REE) is considered a potential source of pollution of environmental media including soils. This work documents critically overview data on the occurrence of REE in the fruiting bodies of wild and farmed species of edible and medicinal mushrooms, as this was identified as the largest published dataset of REE occurrence in foodstuff. Most of the literature reported occurrences of cerium (Ce) and lanthanum (La), but a number of studies lacked data on all lanthanides. The Ce, La, and summed REE occurrences were assessed through the criteria of environmental geochemistry, analytical chemistry, food toxicology, mushroom systematics, and ecology. Ce and La accumulate similarly in fruiting bodies and are not fractionated during uptake, maintaining the occurrence patterns of their growing substrates. Similarly, there is no credible evidence of variable REE uptake because the evaluated species data show natural, unfractionated patterns in accordance with the Oddo-Harkins' order of environmental lanthanide occurrence. Thus, lithosphere occurrence patterns of Ce and La as the first and the third most abundant lanthanides are reflected in wild and farmed mushrooms regardless of substrate and show that Ce is around twice more abundant than La. The current state of knowledge provides no evidence that mushroom consumption at these REE occurrence levels poses a health risk either by themselves or when included with other dietary exposure. Macromycetes appear to bio-exclude lanthanides because independently reported bioconcentration factors for different species and collection sites, typically range from < 1 to 0.001. This is reflected in fruiting body concentrations which are four to two orders of magnitude lower than growing substrates. KEY POINTS: •Original REE occurrence patterns in soils/substrates are reflected in mushrooms •No evidence for the fractionation of REE during uptake by fungi •Mushrooms bio-exclude REE in fruiting bodies.

An insight into the nutritional and medicinal value of edible mushrooms: A natural treasury for human health

Edible mushrooms have been cherished worldwide because of their nutraceutical and medicinal properties. They are recognized as the new superfood for the future due to their low-calorie content, high-protein content, low lipid levels, low cholesterol levels, and abundance of essential vitamins. The fruiting body of edible mushrooms contains a plethora of primary and secondary metabolites. However, submerged cultivation is a more reliable and controlled way of production of mycelium biomass and many bioactive compounds. Several bioactive metabolites present in mushrooms possess a range of beneficial properties, including antioxidant, antimicrobial, anticancer, antidiabetic, anti-inflammatory, antiviral and anti-COVID-19 activities. Consumers have turned more intrigued in mushroom-containing products as the world needs to diversify its protein sources to meet the growing demand for protein. In this context, mushrooms are viewed as a promising source of bioactive chemicals that can be employed as an alternative to meat products. This review aims to summarise the most recent data regarding the beneficial health effects and the development of mushroom-based food products.

Biochemical Properties and Antithrombotic Effect of a Serine Protease Isolated from the Medicinal Mushroom Pycnoporus coccineus (Agaricomycetes)

The purification of a fibrinolytic enzyme from the fruiting bodies of wild-growing medicinal mushroom, Pycnoporus coccineus was achieved through a two-step procedure, resulting in its homogeneity. This purification process yielded a significant 4.13-fold increase in specific activity and an 8.0% recovery rate. The molecular weight of P. coccineus fibrinolytic enzyme (PCFE) was estimated to be 23 kDa using sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. PCFE demonstrated its optimal activity at a temperature of 40 °C and pH 8. Notably, the enzymatic activity was inhibited by the presence of zinc or copper metal ions, as well as serine protease inhibitors, such as phenylmethylsulfonyl fluoride and 4-amidinophenylmethanesulfonyl fluoride. PCFE exhibited remarkable specificity towards a synthetic chromogenic substrate for thrombin. The enzyme demonstrated the Michaelis-Menten constant (Km), maximal velocity (V ), and catalytic rate constant (Kcat) values of 3.01 mM, 0.33 mM min-1 μg-1, and 764.1 s-1, respectively. In vitro assays showed PCFE's ability to effectively degrade fibrin and blood clots. The enzyme induced alterations in the density and structural characteristics of fibrin clots. PCFE exhibited significant effects on various clotting parameters, including recalcification time, activated partial thromboplastin time, prothrombin time, serotonin secretion from thrombin-activated platelets, and thrombin-induced acute thromboembolism. These findings suggest that P. coccineus holds potential as an antithrombotic biomaterials and resources for cardiovascular research.

Disproportionately High Contributions of 60 Year Old Weapons-137Cs Explain the Persistence of Radioactive Contamination in Bavarian Wild Boars

Radionuclides released from nuclear accidents or explosions pose long-term threats to ecosystem health. A prominent example is wild boar contamination in central Europe, which is notorious for its persistently high 137Cs levels. However, without reliable source identification, the origin of this decades old problem has been uncertain. Here, we target radiocesium contamination in wild boars from Bavaria. Our samples (2019-2021) range from 370 to 15,000 Bq·kg-1 137Cs, thus exceeding the regulatory limits (600 Bq·kg-1) by a factor of up to 25. Using an emerging nuclear forensic fingerprint, 135Cs/137Cs, we distinguished various radiocesium source legacies in their source composition. All samples exhibit signatures of mixing of Chornobyl and nuclear weapons fallout, with 135Cs/137Cs ratios ranging from 0.67 to 1.97. Although Chornobyl has been widely believed to be the prime source of 137Cs in wild boars, we find that "old" 137Cs from weapons fallout significantly contributes to the total level (10-68%) in those specimens that exceeded the regulatory limit. In some cases, weapons-137Cs alone can lead to exceedances of the regulatory limit, especially in samples with a relatively low total 137Cs level. Our findings demonstrate that the superposition of older and newer legacies of 137Cs can vastly surpass the impact of any singular yet dominant source and thus highlight the critical role of historical releases of 137Cs in current environmental pollution challenges.

A critical review of the occurrence of scandium and yttrium in mushrooms

Scandium (Sc) and Yttrium (Y) along with the other rare earth elements (REE) are being increasingly extracted to meet the escalating demand for their use in modern high technology applications. Concern has been voiced that releases from this escalating usage may pollute environments, including the habitats of wild species of mushrooms, many of which are foraged and prized as foods. This review collates the scarce information on occurrence of these elements in wild mushrooms and also reviews soil substrate levels, including forested habitats. Sc and Y occurred at lower levels in mushrooms (<1.0-1000 µg kg-1 dw for Sc and<1.8-1500 µg kg-1 dw for Y) compared to the corresponding range for the sum of the lanthanides in the same species (16-8400 µg kg-1 dw). The reported species showed considerably more variation in Y contents than Sc which show a narrow median distribution range (20-40 µg kg-1 dw). Data allowing temporal examination was very limited but showed no increasing trend between the 1970s to 2019, nor were any geographical influences apparent. The study of the essentiality, toxicity or other effects of REE including Sc and Y at levels of current dietary intake are as yet undefined. High intake scenarios using the highest median concentrations of Sc and Y, resulted in daily intakes of 1.2 and 3.3 μg respectively from 300 g portions of mushroom meals. These could be considered as low unless future toxicological insights make these intake levels relevant.

Accumulation and within-mushroom distribution of elements in red cracking bolete (Xerocomellus chrysenteron) collected over the extended period from compositionally contrasting substrates

We conducted a study of elemental compositions of Xerocomellus chrysenteron samples accompanied by samples of related substrate soils. All samples were collected during the harvesting seasons 2021 and 2022 from three forested sites almost unpolluted by recent human activities and underlain by contrasting bedrock (granite, amphibolite, and serpentinite). Elements such as Ag, Cd, K, P, Rb, S, Se, and Zn were the main elements enriched in the mushroom's fruiting bodies relative to the substrate. Concentrations of most elements in mushrooms were not site-dependent, with only Ag, As, Rb, and Se concentrations significantly depending on the bedrock composition. Some elements analyzed in mushrooms displayed temporal features, but such features were not systematic and varied for each element. Most analyzed elements were distributed unevenly within the mushroom's fruiting bodies, with apical parts generally enriched in mobile elements. Mushrooms influenced concentrations of Ag, Cd, K, and Rb and a few other elements in the substrate via uptake, but such influence was very limited and can be responsible for only 2.5-11.5% of total depletion of the affected substrate in the named elements.

In vitro gastrointestinal digestion and bioavailability of lithium from processed lithiated and nonlithiated white Agaricus bisporus mushrooms

AIM

In order to avoid side effects of lithium doses in some patients, some commonly cultivated mushroom species including A. bisporus have been successfully lithiated, with the potential to provide more acceptable sources of Li. This study assessed the in vitro release (potential bioaccessibility) and possible intake of Li using the action of artificial gastrointestinal juices on lithiated and nonlithiated (control) button mushrooms (Agaricus bisporus) that were subjected to certain modes of culinary processing.

METHODS

In the in vitro release study, mushrooms were processed using a number of routinely used domestic treatments including rehydrating dried mushrooms, blanching and blanching followed by pickling of fresh or frozen mushrooms. The in vitro digestion procedure used artificial gastrointestinal juices in a two-stage methodology that was adapted from 'The Bioaccessibility Research Group of Europe' method. The Li concentrations were determined using an inductively coupled argon plasma-dynamic reactive cell-mass spectrometer.

RESULTS

Lithium was found to be more bioaccessible from caps of lithiated mushrooms compared with nonlithiated. Releases from the caps and stipes of blanched or blanched and then pickled mushrooms through gastric digestion ranged from 32 ± 2 to 50 ± 1% relative to the dried product and was lower for gastrointestinal digestion, which ranged from 16 ± 1 to 20 ± 1%.

CONCLUSION

Losses of Li sustained through blanching or blanching followed by pickling of fresh mushrooms (41-87% wet weight) combined with limited accessibility during gastrointestinal release (16-55%) result in much lower bioavailability of the dose from lithiated products. A 300-g meal would provide <5% of the Li (6 mg) required for potential preventative treatments, such as reducing suicide rates and lowering dementia risk.

Comparison of Bioactive Secondary Metabolites and Cytotoxicity of Extracts from Inonotus obliquus Isolates from Different Host Species

Inonotus obliquus, a wood-decaying mushroom, has been used as a health-promoting supplement and nutraceutical for centuries. It is a source of bioactive compounds accumulated in both the conks (pseudosclerotia/sclerotia) and the biomass obtained in vitro. This study aimed to qualitatively and quantitatively analyze the bioelements and selected metabolites produced in mycelial cultures obtained from different host species. The mycochemical potential of mycelial cultures isolated from pseudosclerotia grown in Betula pendula, Alnus glutinosa, and Carpinus betulus was compared. Parent cultures were obtained in two types of medium (malt extract agar substrates without and with birch wood). Experimental cultures were developed in 2 L bioreactors for 10 days. The content of bioelements was determined using FAAS and FAES methods. Organic compounds were estimated using the RP-HPLC-DAD method. The cytotoxicity of the extracts was evaluated in human keratinocytes HaCaT, human skin fibroblasts BJ, human liver cancer HepG2, human melanoma A375, and mouse melanoma B16-F10. The extracts showed the presence of bioelements: sodium, potassium, magnesium, calcium, zinc, manganese, iron, and copper; phenolic acids: p-hydroxybenzoic, caffeic, p-coumaric, and protocatechuic; sterols: lanosterol, ergosterol, ergosterol peroxide; triterpene compounds: betulin, betulinic acid, inotodiol; indole compounds: L-tryptophan, tryptamine, 5-methyltryptamine, melatonin. The content of bioactive substances in the biomass was dependent on both the origin of the host species of the fungus isolate and the type of culture medium. Based on the results of this study, mycelial cultures can be proposed as a potential source of bioactive compounds and are promising naturally derived cytotoxic agents.

Influence of the urban environment on four mushroom species in the light of their elemental composition

The mushrooms are living organisms with excellent capability to adapt to the multiple challenges of their environment. Several species are well represented in urban green areas (parks, green spots, and recreation grounds). We investigated the influence of the urban environment over two saprotrophic (Bovista plumbea, Lycoperdon perlatum) and two mycorrhizal (Amanita rubescens, Suillus granulatus) species commonly present in urban parks of Cluj-Napoca, a major city of Romania. Three control sites close to the city were chosen. We determined 19 elements (Ag, Al, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, S, Si, Sr, Ti, and Zn) in the fruiting bodies of mushrooms and in soils by ICP OES technique. S. granulatus was the most sensible species to the urban pollution; this species accumulated 130 and 4.40 mg kg^-1 (dry weight) median concentrations of Al and Ni, respectively. The highest concentration of Ag, Cu and Fe was determined in B. plumbea (3.18, 83.7 and 141 mg kg^-1, respectively) and L. perlatum (4.68, 91.0 and 125 kg^-1, respectively) collected from the city. The saprotrophic species contained appreciably higher concentrations of Ag, Cu, Fe, Mg, P, and S than the mycorrhizal ones. Common feature of all four species was the higher Ag and Sr concentrations in the fruiting bodies of urban origin. Our results suggest that the unique defence mechanisms of the species might have higher impact over the elemental profile of the mushrooms than the soil properties. We propose L. perlatum and S. granulatus as suitable indicator species of the urban pollution with regard to inorganic pollutants.

Nutritional Value and Antioxidant, Antimicrobial and Cytotoxic Activity of Wild Macrofungi

Macrofungi are among the most promising sources of biologically active natural products with nutritional qualities and therapeutic values. In this work, the nutritional value of nine species of wild macrofungi from Ibague-Tolima (Colombia) was evaluated. In addition the antioxidant, antimicrobial and cytotoxic activities of an ethanol:water (70:30) extract of wild basidiomata were evaluated. The wild mushrooms' nutritional potential showed that the genus Pleurotus and Lentinus have the best protein percentages, with 18.4% and 18.5%. The nine extracts evaluated managed to stabilize the two radicals evaluated; however, lower IC₅₀ was found for Phellinus gilvus and Ganoderma australe extracts. The results showed that Trametes coccinea, Pleurotus floridanus and Ganoderma australe extracts were the most effective as antimicrobials, with high inhibition percentages against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae. Antifungal activity results against Rhizopus oryzae, Penicillium sp. and Aspergillus niger showed that the nine extracts were effective at the concentrations tested. Considering cell viability against isolated leukocytes, seven of the nine extracts showed percentages higher than 50% of cell viability. This research describes the nutritional value of nine wild macrofungi in Colombia and their potential for antimicrobial, cytotoxic and antioxidant activity.

Antioxidant Compounds from Edible Mushrooms as Potential Candidates for Treating Age-Related Neurodegenerative Diseases

The last century has seen an increase in our life expectancy. As a result, various age-related diseases, such as neurodegenerative diseases (NDs), have emerged, representing new challenges to society. Oxidative stress (OS), a condition of redox imbalance resulting from excessive production of reactive oxygen species, represents a common feature that characterizes the brains of elderly people, thus contributing to NDs. Consequently, antioxidant supplementation or dietary intake of antioxidant-containing foods could represent an effective preventive and therapeutic intervention to maintain the integrity and survival of neurons and to counteract the neurodegenerative pathologies associated with aging. Food contains numerous bioactive molecules with beneficial actions for human health. To this purpose, a wide range of edible mushrooms have been reported to produce different antioxidant compounds such as phenolics, flavonoids, polysaccharides, vitamins, carotenoids, ergothioneine, and others, which might be used for dietary supplementation to enhance antioxidant defenses and, consequently, the prevention of age-related neurological diseases. In this review, we summarized the role of oxidative stress in age-related NDs, focusing on the current knowledge of the antioxidant compounds present in edible mushrooms, and highlighting their potential to preserve healthy aging by counteracting age-associated NDs.

Diversity of substrate type, ethnomycology, mineral composition, proximate, and phytochemical compounds of the Schizopyllum commune Fr. in the area along Palu-Koro Fault, Central Sulawesi, Indonesia

Schizophyllum commune Fr. is a wild macro fungus species, which is often used as a food source by the indigenous Kaili tribe along the Palu-Koro fault, Central Sulawesi, Indonesia. This fungus has a wide variety in terms of the weathered wood substrate as a place to grow and is found in almost all types of ecosystems. Although its diversity has been investigated, there is no identification of the weathered wood type as a substrate for growth. Some communities in Indonesia have not also known its potential and benefits. Therefore, this research aims to determine the wood type that grows S. commune fungus, ethnomycology, mineral composition, proximate, and phytochemical compounds. It was carried out using the descriptive explanatory approach and the fungi location as well as wood substrate sampling, was determined through the purposive sampling technique in forest areas, agroforestry, and community gardens along the Palu-Koro fault, Central Sulawesi. The samples of unknown wood types were through the collection of tree parts, namely twigs, leaves, flowers, and fruits, which were brought to Herbarium Celebense, Tadulako University for identification. Analysis of mineral content, proximate, and fungal phytochemical compounds was carried out based on the method according to the existing protocol. The results showed that 92 types of rotted wood found where the fungus S. commune grew, belonged to 36 families. The nutritional content is also good, although it varies based on the type of wood growing media. Therefore, it can be used and processed into various health-beneficial food products. This showed that domestication of the fungus needs to be carried out to support its commercialization as food and medicine in the future.

Vitamin D from UV-Irradiated Mushrooms as a Way for Vitamin D Supplementation: A Systematic Review on Classic and Nonclassic Effects in Human and Animal Models

Recent literature has shown that vitamin D, in addition to its well-known activity on the skeleton, has many positive effects on health. Unfortunately, it is not easy to meet intake needs solely with food. Mushrooms could provide a valid way to achieve this goal, because they are one of the few sources of vitamin D. The aim of this systematic review was to summarize what has been reported in the literature on the treatment of animal and human models with irradiated commercial mushrooms, with particular attention paid to the effects on clinical outcomes associated with the classical and nonclassical vitamin D functions. A total of 18 articles were selected. Six studies were conducted on human samples, while twelve were focused on animal models. The six studies conducted in humans involved a large number of subjects (663), but the treatment period was relatively short (1–6 months). Furthermore, the treatment dosage was different in the various groups (600–3800 IU/day). Probably for this reason, the studies did not demonstrate clinical efficacy on the parameters evaluated (cognitive functions, muscle system/function, metabolic syndrome). Indeed, those studies demonstrated an efficacy in increasing the blood levels of 25(OH)D2, but not in increasing the levels of 25(OH)D total. In 9 of 12 studies conducted on the animal model, however, a clinical efficacy on bone metabolism, inflammation, and cognitive performance was demonstrated. The results of this systematic review indicate that the intake of vitamin D from irradiated mushrooms could possibly help to meet vitamin D needs, but the dosage and the time of treatment tested need to be evaluated. Therefore, studies conducted in humans for longer periods than the studies carried out up to now are necessary, with defined dosages, in order to also evaluate the clinical efficacy demonstrated in animal models both for the classical (bone metabolism) and nonclassical (muscle function, cognitive performance, anti-inflammatory, and antioxidant activities) effects of vitamin D.

Risk Assessment of the Wild Edible Leccinum Mushrooms Consumption According to the Total Mercury Content

Wild-growing edible mushrooms contain many biologically valuable substances. However, they are considered a risk commodity due to their extremely high capacity for bioaccumulation of potential risk elements and pollutants from the environment. Four bolete mushrooms from the genus Leccinum were collected from 16 forested areas of Slovakia from June to October 2019. The total mercury content in soil and fruiting body parts was determined by an AMA-254 Advanced Mercury Analyzer. Soil pollution by total mercury was evaluated by contamination factor (Cfi). Bioaccumulation factor (BCF), translocation factor (Qc/s), percentage of provisional tolerable weekly intake (%PTWI), and target hazard quotient (THQ) were used to describe and compare uptake and transition abilities of mushrooms, and the health risk arising from consumption of the mushrooms. Total mercury content varied between 0.05 to 0.61 mg kg−1 DW in the soil/substrate samples, and between 0.16 and 5.82 (caps), and 0.20 and 3.50 mg kg−1 DW (stems) in fruiting body samples. None of the analyzed locations represented a health risk based on %PTWI values, however, three locations may pose a significant health risk from the perspective of THQ values.

Cadmium in the hyperaccumulating mushroom Thelephora penicillata: Intracellular speciation and isotopic composition

Thelephora penicillata is an ectomycorrhizal mushroom that can accumulate extraordinarily high concentrations of Cd, As, Cu, and Zn in its fruit-bodies. To better understand its element accumulation ability, we compared the element concentrations in T. penicillata with 10 distinct ectomycorrhizal mushroom species growing at the same site (Karlina Pila, Czech Republic). On average, T. penicillata accumulated 330, 2130, 26, and 4 times more Cd, As, Cu, and Zn, respectively, than other mushrooms. Size-exclusion chromatography and an electrophoretic analysis of T. penicillata cell extracts indicate that intracellular Cd may be present mainly in >1 kDa, presumably compartmentalized, Cd species, and partially binding with 6-kDa cysteinyl-containing peptide(s) resembling metallothioneins. The cadmium isotopic composition of mushroom fruit-bodies, soil digests, and soil extracts was investigated by thermal ionization mass spectrometry (TIMS) with double spike correction. The isotopic composition (δ^114/110Cd) of ectomycorrhizal mushrooms from Karlina Pila varied in a wide range of -0.37 to +0.14 ‰. However, remarkably low δ^114/110Cd values were observed in the majority of the investigated mushrooms when compared to the relatively homogeneous Cd isotopic composition of bulk soil (δ^114/110Cd = +0.09 ‰) and the comparatively heavy isotopic composition of soil extracts (mean δ^114/110Cd values of +0.11 ± 0.01 ‰ and +0.22 ± 0.01 ‰, depending on the extraction method). The isotopic composition of Cd hyperaccumulated in T. penicillata essentially matched the mycoavailable soil Cd fraction. However, most isotopic data indicates isotopic fractionation at the soil/fruit-body interface, which could be of environmental significance.

Comment on “Screening the Multi-element Content of Pleurotus Mushroom Species Using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES)”

La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu are lanthanides, also referred to as “rare earth” elements (occurring at ultra-low concentration, i.e. each, at ppb or lower levels) in plant and animal foods including edible wild mushrooms. Could it be that lanthanides when collectively reported as a summed value (widely referred to as REE) are at relatively high concentrations because extremely high contributions from individual elements? REE elements naturally occur in environmental media such as the soil substrate in which plants and fungi grow in a characteristic pattern (Oddo-Harkins rule), with most of the available literature confirming the extension of this pattern in fungi. Abnormalities therefore need to be examined closely and resolved.

Occurrence, bio-concentration and distribution of rare earth elements in wild mushrooms

Using validated methodology, this study explores the bioconcentration potential and status of rare earth elements (REE) and yttrium (Y) in wild mushrooms collected from Belarus, China and Poland and in the associated forest topsoil. Baseline data for REE and Y distributions in the morphological parts of the fruiting bodies of Caloboletus calopus, Cantharellus cibarius, Craterellus cornucopioides, Imleria badia, Laccaria amethystina, Lactifluus piperatus, Leccinum scabrum and Suillus grevillei are presented. REE were in the range of 14 to 42 mg kg^-1 dw in forest topsoil and from 35 to 48 mg kg^-1 dw in profiled soil layers from the Sobowidz site in Poland. Forest topsoil sampled in Belarus contained 67 mg kg^-1 dw. Yttrium concentrations in soil ranged from 2.9 to 10 mg kg^-1 dw. The median REE concentration in wild mushrooms was around 200 μg kg^-1 dw (20 μg kg^-1 fresh weight). This implies negligible dietary intake even for high level consumers. The bioconcentration factors (BCF) of individual REE and Y ranged from 0.0002 to 0.0229, showing bio-exclusion. The BCF tended to be similar for groups of REE (La to Tb and Dy to Lu) depending on the mushroom species and site. REE from Dy to Lu were better bioconcentrated than those from La to Tb. The similarity of the BCFs of individual REE by species at a given site implies the same absorption pathway, although a lower concentration in the topsoil favoured bioconcentration. REE and Y concentrations varied between species as well as within the same species between sites. Their accumulation in mushrooms appears to reflect condition at the site of collection, and may also be species-specific but confirming this would require further investigation of different species, topsoils and sites.

Elucidating Heavy Metals Concentration and Distribution in Wild Edible Morels and the Associated Soil at Different Altitudinal Zones of Pakistan: a Health Risk Implications Study

This study evaluates macro-nutrient (MN) and prevailing heavy metal (HM) concentrations in wild edible morels (WEM) species viz., Morchella crassipes, Morchella pulchella, and Morchella eohespera and the associated soil that were collected from different altitudinal zones (Azad Kashmir, Murree, Swat, and Skardu) of Pakistan. A special emphasis on potential health risk analysis for HM in WEM consumption was also explored. In general, MN concentration in fruiting bodies and their associated soil samples were in the following order: potassium (K) > magnesium (Mg) > calcium (Ca) > sodium (Na) and Ca > Mg > K > Na, respectively. The concentration for HM in WEM ranged between 20.0 and 78.0 mg/kg, 1.09 and 22.1 mg/kg, 2.1 and 22.1 mg/kg, 0.26 and 13.1 mg/kg, 0.43 and 9.1 mg/kg, 1.07 and 7.0 mg/kg, 1.01 and 5.4 mg/kg, and BDL and 3.1 mg/kg for zinc (Zn), copper (Cu), nickel (Ni), manganese (Mn), cobalt (Co), chromium (Cr), lead (Pb), and cadmium (Cd), respectively, and those in underlying soil samples, lowest and highest HM concentration were recorded for Zn (33.7-113.6 mg/kg), Cu (13.0-40.8 mg/kg), Ni (3.1-23.0 mg/kg), Pb (1.3-22.0 mg/kg), Co (2.9-5.6 mg/kg), Cr (2.7-11.1 mg/kg), Mn (2.0-7.1 mg/kg), and Cd (1.1 mg/kg 7.6). Although, Cd, Pb, and Zn concentrations in some of the WEM samples and Cd in the soil had exceeded the permissible limits set by different organizations. The greater accumulation/or transfer potential for Zn, Co, Ni, and Cu were recorded in WEM from their associated soil. The health risk index (HRI) for HM in all assessed samples of WEM was < 1, predicting no risk to the consuming population. Furthermore, the correlation analyses depicted that the power of hydrogen (pH), low organic matter contents, and sandy texture are likely to be responsible for HM transfer to the lower pool of soil. But the increasing concentration of HM in WEM warrants threats and suggests further monitoring and future policy plan and implementation to avoid the potential health risks via its regular consumption.

Risk assessment of mercury through dietary exposure in China

Mercury (Hg) is a widespread heavy metal causing various damages to health, while insufficient studies assessed its exposure risk across China. This study explored concentrations in food items and dietary exposure risks across China by comprehensively analyzing the researches on total Hg (THg) in eight food items and methylmercury (MeHg) in aquatic foods published between 1980 and 2021. According to the included 695 studies, the average THg concentration in all food items was 0.033 mg/kg (ranging from 0.004 to 0.185 mg/kg), with the highest concentration in edible fungi. The average daily dietary THg exposure from all foods was 12.9 μg/day. Plant-based foods accounted for 62.7% of the dietary THg exposure. Cereals and vegetables were the primary source of THg exposure. The MeHg concentration in aquatic foods was 0.08 mg/kg, and the average dietary exposure was 3.8 μg/day. Monte Carlo simulations of the dietary exposure risk assessment of THg and MeHg showed that approximately 6.4 and 7.0% of residents exceeded the health-based guidance value set by the European Food Safety Authority, with higher exposure risk in Southwest and South China. The nationwide target hazard quotient index of THg was greater than 1, suggesting that the non-carcinogenic risk of dietary exposure to THg needed further concern. In summary, this study has a comprehensive understanding of dietary Hg exposure risks across China, which provide a data basis for Hg exposure risk assessment and policy formulation.

Activity concentrations and bioconcentration factors (BCFs) of natural radionuclides (40 K, 226Ra, and 232Th) from cultivated substrates to mushrooms

This study examined 42 mushroom samples and corresponding cultivated substrates. The radionuclide activity concentrations and bioconcentration factor (BCF) from substrate-to-mushroom were determined. The substrate activity concentrations were 59.1-727.5, 4.5-37.6, and 4.0-53.0 Bq/kg dw (dry weight) for 40 K, 226Ra, and 232Th, respectively. The average 40 K concentrations were 1546.5, 1115.7, and 749.3 Bq/kg dw; the BCFs were 2.49, 3.56, and 5.58 for A. bisporus, F. velutipes, and L. edodes, respectively. The 40 K concentrations were insignificantly correlated with each species' corresponding substrate concentration. The 40 K BCFs had a significantly negative correlation with the substrate concentration for each species. Each mushroom species' 40 K concentration was almost stable, suggesting that 40 K has a regulated homeostasis for a given species. The average 226Ra concentrations were 5.5, 5.4, and 3.4 Bq/kg dw; the BCFs were 0.58, 0.17, and 0.50 for L. edodes, A. bisporus, and F. velutipes, respectively. The average 232Th concentrations were 4.7, 4.7, and 3.0 Bq/kg dw; the BCFs were 0.50, 0.11, and 0.53 for L. edodes, A. bisporus, and F. velutipes, respectively. The 226Ra and 232Th concentrations in mushrooms had a weak to moderate correlation with the cultivated substrate concentrations. The absorption of the 226Ra and 232Th from substrate-to-mushroom was similar to the hypothesis of the linear model that mushroom concentration yields a positive correlation with substrate concentration.

Quantitative mapping of mercury and selenium in mushroom fruit bodies with laser ablation-inductively coupled plasma-mass spectrometry

This work describes the development of a novel method for quantitative mapping of Hg and Se in mushroom fruit body tissues with laser ablation coupled to inductively coupled plasma-mass spectrometry (LA-ICP-MS). Different parameters of the protocol for preparation of the standards used for quantification via external calibration were assessed, e.g., the dissolution temperature of gelatin standards and the addition of chitosan and L-cysteine as additives to the gelatin-based calibration droplets to better match the sample matrix. While chitosan was not suited for this purpose, the presence of L-cysteine considerably improved the figures of merit of the calibration, leading to limits of detection of 0.006 and 0.3 µg g-1 for Hg and Se, respectively, at a pixel size of 20 × 20 µm. Further, an in-house reference material, ideally suited for the validation of the method for application to mushroom samples, was successfully prepared from a paste of Boletus edulis. The newly developed method was used to investigate the distribution of Hg and Se in tissue sections of five porcini mushroom individuals of three different species (Boletus edulis, Boletus aereus, and Boletus pinophilus) and one sample of a parasol mushroom (Macrolepiota procera). For one sample, additional areas were ablated at higher spatial resolution, with a laser spot size down to 5 µm, which allows a detailed investigation of the spatial distribution of Hg and Se in mushrooms.

Road traffic and abiotic parameters of underlying soils determine the mineral composition and nutritive value of the mushroom Macrolepiota procera (Scop.) Singer

The effectiveness of accumulating mineral elements by wild-growing mushrooms depends mainly on species, their growth place, and the underlying soil's chemical characteristics. The aim of the study was to determine the effect of road traffic and the role of chemical characteristics of soil on the mineral composition of Macrolepiota procera fruit bodies growing in close proximity to a road and an adjacent forest during a four-year period. The concentrations of the majority elements (mainly Al, Cd, Co, Cr, Cu, Pb, Ti, and Zn) in the soil near the road were significantly higher than those in the forest soil, which was reflected in the fruit bodies which contained a higher amount of these elements. While the accumulation of heavy metals and other elements in the M. procera fruit bodies did not depend on the total soil organic carbon content, the degree of their decomposition determined by the C:N ratio and the individual fractions of organic carbon had a significant influence. Our studies show that soil properties are highly variable in the natural habitats of M. procera, which affects the efficiency of element accumulation. Macrolepiota procera fruit bodies growing in soil with similar chemical properties were characterized by different mineral compositions. Moreover, the obtained results indicate that the fruit bodies of edible M. procera, not only those close to roads but also at a greater distance, may contain significant amounts of toxic As and Cd, which could pose a health risk if consumed. Although most studies describing the mineral composition of M. procera fruit bodies have found no evidence to question the safety of their consumption, this species can effectively accumulate selected elements when growing immediately beside roads or in their close proximity.

Rare Earth Elements in Boletus edulis (King Bolete) Mushrooms from Lowland and Montane Areas in Poland

Mining/exploitation and commercial applications of the rare-earth elements (REEs: La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) in the past 3 decades have raised concerns about their emissions to the environment, possible accumulation in food webs, and occupational/environmental health effects. The occurrence and distribution of REEs Y and Sc in the fruitbodies of Boletus edulis collected from geographically diverse regions in Poland were studied in 14 composite samples that were derived from 261 whole fruiting bodies. Individual REE median concentrations ranged from 0.4–95 µg kg⁻¹ dry weight (dw). The summed REE concentrations varied widely, with a median value of 310 µg kg⁻¹ dw and a range of 87 to 758 µg kg⁻¹. The Sc and Y median concentrations (dw) were 35 and 42 µg kg⁻¹, respectively. Ce, La, and Nd, with median values of 95, 51, and 32 µg kg⁻¹, respectively, showed the highest occurrence. B. edulis collected from a forested area formerly used as a military shooting range—possibly a historically contaminated site—had an elevated summed REE content of 1796 µg kg⁻¹. REE concentrations were generally low in Polish King Bolete. Dietary intake from a mushroom meal was negligible, posing no health risk to consumers.

Occurrence, distribution, and associations of essential and non-essential elements in the medicinal and edible fungus "Fuling" from southern China

In Asian countries, the sclerotia of the wild-grown fungus Pachyma hoelen ("Fuling"), have been used as food and as medicinal products for centuries. To close the knowledge gaps about the value and possible environmental impacts, the occurrence, distribution, and associations of a range of elements (Ag, Al, As, Ba, Cd, Co, Cr, Cs, Cu, Li, Mg, Mn, Ni, Pb, Rb, Sb, Sr, Tl, U, V, and Zn) were studied in the inner (core) and outer (shell) morphological parts of the sclerotia from a diverse collection in Southern China. Quality of forest and agricultural soil in terms of a geogenic element source and composition can be considered as the main factor determining the occurrence of minerals in sclerotia through the host wood, largely of Pinus yunnanensis, while the anthropogenic impact (basically at remote rural areas of cultivation) in Southern China was negligible. In general, the mean concentration of each element in the outer part was significantly higher than that in the inner part (t-test, p < 0.01), except for Ag. The concentration of a given element in the outer part tended to have a positive relationship with that in the inner part, except for Cu, Se, Ag, and Zn. The elements in different morphological parts of sclerotia present different relation patterns. Compared to the outer part, there were stronger associations of elements in the inner part, suggesting homeostatic regulation of multiple elements in the inner parts. Further study on the sclerotia, infected wood substrate, and surrounding soil from a range of wild sample collections and intentional cultivation should provide a more complex view and allow assessment of the relationship between minerals and bioactive organic compounds produced by P. hoelen.

Occurrence and Health Risk Assessment of Cadmium Accumulation in Three Tricholoma Mushroom Species Collected from Wild Habitats of Central and Coastal Croatia

This study deals with the biomonitoring of cadmium (Cd) heavy metal in the three selected Tricholoma mushroom species collected from wild habitats of central and coastal Croatia. For this, mushroom (T. columbetta: n = 38, T. portentosum: n = 35, and T. terreum: n = 34) and surface soil samples were collected from nine forest localities of Croatia and analyzed for Cd concentration using inductively coupled plasma−optical emission spectrometry (ICP−OES) through the acid digestion method. The findings revealed that Cd was present in Tricholoma spp. and surface soil. However, the maximum mean Cd concentration (mg/kg dry weight) was recorded in T. portentosum (cap: 0.98; stipe: 0.72), followed by T. columbetta (cap: 0.96; stipe: 0.73) and T. terreum (cap: 0.81; stipe: 0.63). The bioconcentration factor (BCF) value (>1) revealed that the selected Tricholoma spp. had the potential for Cd accumulation. Moreover, the principal component (PC) and hierarchical cluster (HC) analyses were used to derive the interactions and similarities between Cd levels Tricholoma spp. and sampling localities. The multivariate analysis suggested that central sampling localities had higher Cd levels as compared to coastal localities. However, the daily intake of metals (DIM < 0.426) and health risk index (HRI < 1) showed that there was no potential health risk associated with the consumption of selected Tricholoma spp. The findings of this study are helpful to understand the Cd accumulation behavior of wild edible Tricholoma spp. collected from Croatia.

A new mushroom hyperaccumulator: Cadmium and arsenic in the ectomycorrhizal basidiomycete Thelephora penicillata

Fruit-bodies of six Thelephora species (Fungi, Basidiomycota, Thelephoraceae) were analyzed for their trace element concentrations. In Thelephora penicillata, extremely high concentrations of Cd and As were found, followed by highly elevated concentrations of Cu and Zn. The highest accumulation ability was found for Cd with a mean concentration of 1.17 ± 0.37 g kg^-1 (dry mass) in fruit-bodies collected from 20 unpolluted sites; the mean As concentration was 0.878 ± 0.242 g kg^-1. Furthermore, striking accumulation of Se (923 ± 28 mg kg^-1) was found in one sample of T. vialis and elevated concentrations of S were detected in T. palmata (19.6 ± 5.9 g kg^-1). The analyzed Thelephora species were sequenced and, based on the Maximum Likelihood phylogenetic analysis (ITS rDNA) of the genus, possible other Thelephora (hyper)accumulators were predicted on the basis of their phylogenetic relationship with the discovered (hyper)accumulators. The striking ability of T. penicillata to accumulate simultaneously Cd, As, Cu, and Zn has no parallel in the Fungal Kingdom and raises the question of a biological importance of metal(loid) hyperaccumulation in mushrooms.

Fungus–Fungus Association of Boletus griseus and Hypomyces chrysospermus and Cadmium Resistance Characteristics of Symbiotic Fungus Hypomyces chrysospermus

Fungi bioaccumulation of heavy metals is a promising approach to remediate polluted soil and water. Boletus griseus could accumulate high amounts of Cd, even in a natural habitat with low Cd contents. This study found a symbiotic association of B. griseus with a fungus. The symbiotic fungus was isolated and identified as Hypomyces chrysospermus. The isolated strain had a strong ability to tolerate Cd. The minimum inhibitory concentration of Cd of fungal growth was 200 mg·L−1. The Cd bioaccumulation capacity of the fungus reached 10.03 mg·g−1. The biomass production of the fungus was promoted by 20 mg·L−1 Cd. However, high concentrations of Cd suppressed fungal growth and significantly altered the morphology and fine texture of fungal hyphae and chlamydospores. The immobilization effects of the cell wall and acid compounds and antioxidant enzymes were employed by the fungus to alleviate the toxic effects of Cd. The results not only demonstrate a new insight into the Cd bioconcentration mechanisms of B. griseus but also provide a potential bioremediation fungus for Cd contamination.

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.

Potential Uses of Scallop Shell Powder as a Substrate for the Cultivation of King Oyster Mushroom (Pleurotus eryngii)

Scallop shells are currently a major form of waste generated in the Chinese fishing industry. However, they have the potential to be used as important industrial products. This study was conducted to assess the utility of scallop shell powder (SSP) supplementation in improving the growth of king oyster mushrooms (Pleurotus eryngii) grown on sawdust and sugarcane bagasse substrates. The outcomes of interest included mycelial growth, yield, biological efficiency, fruiting body traits, nutrient supply, and the mineral composition of P. eryngii. Supplementation with SSP accelerated the mycelial growth of P. eryngii. The yield of fruiting bodies (399.5 g/bag) and the biological efficiency (84.6%) were 14% higher after supplementation of the substrate with 2% SSP compared with those of mushrooms grown on substrates not supplemented with SSP (349.8 g/bag and 74.0%, respectively). Moreover, the crude protein and fiber contents of the fruiting bodies significantly improved after growth with SSP. Furthermore, supplementation with 2% SSP increased the calcium (Ca) content of the fruiting bodies of P. eryngii by 64% (to 67.2 ± 15.7 mg kg−1) compared with that of mushrooms grown on a control substrate (41.0 mg kg−1). This study revealed that P. eryngii can efficiently use the Ca provided by raw SSP, generating higher Ca contents in their fruiting bodies. Our results demonstrate that the supplementation of substrates with SSP can be useful for enhancing both the yield and nutritional content of P. eryngii.

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.

Mercury in scarletina bolete mushroom (Neoboletus luridiformis): Intake, spatial distribution in the fruiting body, accumulation ability and health risk assessment

In the present work, we focused on two aspects of mercury (Hg) bioconcentration in the above-ground parts of Neoboletus luridiformis. In the first part, we monitored the bioconcentration potential of individual anatomical parts of a particular fruiting body and evaluated the obtained data by the spline interpolation method. In the second part, we focused on assessing the mercury content in 378 samples of N. luridiformis and associated samples of substrates from 38 localities with different levels of Hg content in Slovakia. From the obtained data of Hg content in samples of substrate and fungi, we evaluated ecological indicators (geoaccumulation index - Igeo, contamination factor - Cf a potential ecological risk - PER), bioconcentration indicators (bioconcentration factor - BCF; cap/stipe quotient - Qc/s) and health indicators (percentage of provisional tolerable weekly intake - %PTWI a target hazard quotient - THQ). Based on the Hg distribution results, the highest Hg content was found in the tubes & pores (3.86 mg/kg DW), followed by the flesh of cap (1.82 mg/kg DW). The lowest Hg content was in the stipe (1.23 mg/kg DW). The results of the BCF values indicate that the studied species can be included in the category of mercury accumulators. The results of the ecological indices representing the state of soil pollution pointed out that two localities (Malachov and Nižná Slaná) stood apart from all monitored localities and showed a state of an extremely disturbed environment. This fact was also reflected in the values of Hg content in the fruiting bodies of the studied mushroom species. In the case of the consumption of mushrooms from these localities, it can be stated that long-term and regular consumption could have a negative non-carcinogenic effect on the health of consumers. It was confirmed by the %PTWI (Malachov: 57.8%; Nižná Slaná: 53.2%) and THQ (Malachov: 1.11 Nižná Slaná: 1.02). The locality Čačín-Jelšovec is interesting from the bioconcentration characteristics point of view, where the level of environmental pollution was the lowest (Hg content in the soil was below the background value) compared to other localities, however, the THQ value was the highest (1.29).

Anthropogenic contamination leads to changes in mineral composition of soil- and tree-growing mushroom species: A case study of urban vs. rural environments and dietary implications

Because wild-growing edible mushroom species are frequently consumed, a knowledge of their mineral composition is essential. The content of elements in mushrooms and their possible beneficial or harmful effect may be influenced by the human-impacted environment. Thus, the aim of the study was to analyse the mineral composition of the soil, trees, and especially soil- and tree-growing mushroom species collected from within a city and from rural areas. Due to potentially higher pollution in urban areas, we assumed that mushrooms from a city environment will contain higher levels of mineral elements than those from rural areas and that the high content will be attributed to greater contamination of city soils. Significantly higher concentrations of several elements in soils (Ca, Ba, Bi, Hg, Pb, Sb, Sr, W and Zr) and trees (Ag, Bi, Ce, Co, Mn, Mo, Nd, Pr, Ta, Tm and W) were observed from the samples collected in the city. Additionally, significantly higher contents of Ag, Fe, Hg, Mn, Mo, Sr, Y and Zn in soil-growing, and Al, As, Ba, Cr, Fe, Hg, Ni, Pb, Sr, Ta and Zn in tree-growing mushroom species were recorded from the urban area. These differences formed the basis for the observation that the content of elements in urban mushrooms is generally higher than in those from rural areas. However, a higher content of several soil elements does not necessarily mean that there will be a significantly higher content in fruit bodies. There was also no real risk of consuming soil-growing mushroom species collected in recent years from the city, suggesting that this practice may still be continued.

Effect of drying, blanching, pickling and maceration on the fate of 40K, total K and 137Cs in bolete mushrooms and dietary intake

The effects of blanching, blanching and pickling and maceration on the leaching of ¹³⁷Cs and ⁴⁰K from the flesh of three edible bolete mushroom species-Boletus edulis, Leccinum scabrum and Leccinum versipelle-were investigated. Significant (p < 0.05) decreases in activity were observed but varied depending on the treatment. Relative to fresh mushrooms, blanching decreased the activity concentration of ¹³⁷Cs by 15 ± 13%, and of ⁴⁰K, by 16 ± 7%, but blanching and pickling (vinegar) reduced activity more effectively, by 55 ± 8% and 40 ± 20% respectively. The corresponding losses of ¹³⁷Cs and ⁴⁰K through maceration of dried, powdered mushrooms were 38 ± 11% and 35 ± 14% ww, respectively. These results indicate that traditional domestic processing methods may not be as efficient at excluding ¹³⁷Cs radioactivity as shown in some other studies. The activity concentration of ¹³⁷Cs in a typically sized (100 g) portion of a processed mushroom (sourced from nearshore regions of the southern Baltic Sea coast near Gdańsk in 2015) meal was projected to be low, i.e. in the range of 0.51 to 12 Bq kg^-1 ww. The corresponding effective dose of ¹³⁷Cs from blanched, blanched and pickled and macerated mushrooms per capita was also assessed to be low, from 0.001 to 0.010 μSv. Nutritionally, the median concentration of potassium (330 mg) in 100 g portions of blanched or pickled mushrooms would account for around 7% of the adequate adult daily intake.

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.

Distribution and Origin of Major, Trace and Rare Earth Elements in Wild Edible Mushrooms: Urban vs. Forest Areas

This paper investigates the composition of major, trace, and rare earth elements in 15 different species of wild edible mushrooms and the possible effect of urban pollution on elemental uptake. The collected mushrooms include different species from the green areas of the city, exposed to urban pollution, and from the forests, with limited anthropogenic influence. Through a comprehensive approach that included the analysis of 46 elements, an attempt was made to expand knowledge about element uptake by mushroom fruiting bodies. The results showed a wide variability in the composition of mushrooms, suggesting a number of factors influencing their element uptake capacity. The data obtained do not indicate significant exposure to anthropogenic influences, regardless of sampling location. While major elements’ levels appear to be influenced more by species-specific affinities, this is not true for trace elements, whose levels presumably reflect the geochemical characteristics of the sampling site. However, the risk assessment showed that consumption of excessive amounts of the mushrooms studied, both from urban areas and from forests, may have adverse health effects.

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.

Cadmium and Lead Content in Selected Fungi from Poland and Their Edible Safety Assessment

Mushrooms are able to accumulate toxic trace elements. This study investigates the content of cadmium (Cd) and lead (Pb) in selected species of fungi (Boletus badius, Boletus edulis, and Cantharellus cibarius) from the northeastern part of Poland and estimates their edible safety. The amount of Cd and Pb was determined by flameless atomic spectrometry using the iCE 3000 Series-Thermo. The mean content of Cd in analyzed mushrooms ranged from 0.370 to 2.151 mg/kg d.w., while Pb was found at the level of 0.243–0.424 mg/kg d.w. Boletus edulis was characterized by the highest content of Cd, whereas Cantharellus cibarius contained the biggest amount of Pb. Estimated exposure to the Cd intake expressed as percentage share in TWI (Tolerable Weekly Intake) was at the highest level in Boletus edulis (30.87%), which could be associated with the risk of excessive Cd accumulation in the body.

Natural radioactivity and total K content in wild-growing or cultivated edible mushrooms and soils from Galicia (NW, Spain)

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.

The content of silver, aluminum, and zinc in wild edible mushroom Macrolepiota procera

The content of selected elements (Ag, Al, and Zn) in wild edible Parasol mushroom (Macrolepiota procera Scop. Singer) collected from five sites in Slovakia – Lazy pod Makytou, Lozorno, Nemečky, Tesáre, and Zbyňov was investigated. The element analysis was determined using the ICP-OES method. The average concentrations of Ag, Al, and Zn in M. procera caps ranged as follows: 0.41 – 3.23, 16.6 – 113, and 73.4 – 111 mg kg-1 dry weight, respectively. Also, Spearman’s correlation test was used to determine the correlations between Parasol mushroom caps and stems in the content of Ag, Al, and Zn. Subsequently, the obtained data on the content of the monitored elements in M. procera caps were used for the evaluation of health risks arising from the consumption of M. procera. Although mushrooms are an important part of the diet, they are consumed mainly as a seasonal delicacy therefore, the intake of the monitored elements from the consumption of M. procera may be limited. Regular and long-term consumption of M. procera caps from investigated sites does not pose any health risks to the consumers.

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.