Macro- and microelement contents in fruiting bodies of wild mushrooms from the Notecka forest in west-central Poland

The concentrations of microelements in forest mushrooms are influenced by soil pH and C/N ratio and less by stand characteristics

The fruitbodies or sporocarps formed by mushrooms can accumulate mineral elements, such as selenium, zinc or copper, making them an important source of micronutrients essential to humans. However, the literature about environmental factors affecting mineral composition in mushrooms is scarce and limited to the ambiguous impact of soil properties and region. In our study, we investigated the effects of tree stand characteristics (tree species and tree canopy cover), understory cover, and soil properties (pH and C/N ratio of the soil) on the concentration of minerals in six edible mushroom species: Laccaria laccata, L. proxima, L. amethystina, Lepista nuda, Lycoperdon perlatum, and Calvatia excipuliformis, collected on 20 plots covered by stands of different tree species composition and varying in the understory cover. We estimated the concentration of eight elements (Zn, Se, Mg, Mn, Cu, Co, Cr, Mo) using the ICP-MS (Inductively Coupled Plasma - Mass Spectrometry) technique and compared their concentration between the plots, using ordination and linear regression methods. Our research revealed that mushroom species identity, including its ecological role and phylogenetic affinity, had the greatest effect on the mineral composition of mushrooms. The effect of environmental factors depended also on the micronutrient identity. Some elements were not affected at all (Co, Cr), some only by soil reaction or C/N ratio (Mn, Mg, Cu), while others were influenced by both tree stand characteristics and soil properties (Se, Zn, Mo). This knowledge enables us to maximize the content of minerals in harvested mushrooms by collecting them in specific areas. For example, mushrooms, which are sources of Se and Zn, can be gathered in coniferous forests characterized by acid soils, low canopy cover, and minimal understory cover. This targeted collection approach can effectively increase the mineral content in harvested mushrooms, thereby enhancing their health benefits.

GIS-based Visualization of Elemental Distribution in Neoboletus Luridiformis Fruiting Body

The fruiting body of Neoboletus luridiformis (Scarletina bolete) mushroom was used to determine the level of bioconcentration and subsequent distribution of seventeen elements (Ag, Al, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Se, Sr, and Zn). A two-centimeter-thick vertical section of the entire fruit body was divided into 101 partial sub-samples where the contents of the studied elements were determined using ICP OES. The actual distribution of the elements in the fruiting body profile was visualized using a GIS interpolation method resulting in distribution maps. The study provides valuable insights into the distribution patterns of 17 elements within the fruiting body of N. luridiformis. Based on the visualization of the elemental content, the determined elements can be divided into three categories. Elements accumulated primarily (i) in the cap (Al, Ag, Ca, Cd, Cu, Fe, K, Mg, Ni, and Zn), (ii) in the stipe (Ba, Mn, Na, Pb, and Se), and (iii) elements with non-specific distribution (Cr and Sr). Since such detailed information supported by graphical visualization has not been published to date, the information in this study will help to better understand the accumulation and distribution of elements within the fruiting bodies of wild as well as cultivated mushroom species.

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.

Essential Mineral Content (Fe, Mg, P, Mn, K, Ca, and Na) in Five Wild Edible Species of Lactarius Mushrooms from Southern Spain and Northern Morocco: Reference to Daily Intake

Mushroom consumption has increased in recent years due to their beneficial properties to the proper functioning of the body. Within this framework, the high potential of mushrooms as a source of essential elements has been reported. Therefore, the present study aims to determine the mineral content of seven essential metals, Fe, Mg, Mn, P, K, Ca, and Na, in twenty samples of mushrooms of the genus Lactarius collected from various locations in southern Spain and northern Morocco, by FAAS, UV-Vis spectroscopy, and ICP-OES after acid digestion. Statistics showed that K was the macronutrient found at the highest levels in all mushrooms studied. ANOVA showed that there were statistically significant differences among the species for K, P, and Na. The multivariate study suggested that there were differences between the accumulation of the elements according to the geographic location and species. Furthermore, the intake of 300 g of fresh mushrooms of each sample covers a high percentage of the RDI, but does not meet the recommended daily intake (RDI) for any of the metals studied, except for Fe. Even considering these benefits, the consumption of mushrooms should be moderated due to the presence of toxic metals, which may pose health risks.

Bioaccumulation of Macronutrients in Edible Mushrooms in Various Habitat Conditions of NW Poland-Role in the Human Diet

Recently, the interest in mushroom consumption has been growing, since their taste and low calorific value are appreciated, but also due to their nutritional value. In determining the usefulness of mushrooms in the human diet, it is important to consider the conditions of their occurrence to perform the assessment of bioaccumulation of minerals. The aim of the study was: (a) to determine the content of selected macronutrients (P, K, Ca, Mg, Na) in fruiting bodies of Boletus edulis, Imleria badia, Leccinum scabrum and the soils, (b) to determine their bioaccumulation potential taking into account the habitat conditions, and (c) an attempt to estimate their role in covering the requirement for macronutrients of the human organism. The research material was obtained in the NW of Poland: Uznam and Wolin, the Drawa Plain and the Ińsko Lakeland. In the soil, we determined the content of organic matter, pH, salinity and the content of absorbable and general forms of macronutrients. The content of macronutrients in mushrooms was also determined. Chemical analyses were performed using the generally accepted test methods. The study showed that in NW Poland, B. edulis grew on the acidic soils of Arenosols, and I. badia and L. scabrum grew on Podzols. The uptake of K, Mg and Ca by the tested mushrooms was positively, and P and Na negatively correlated with the content of these elements in the soil. The acidity of the soil affected the uptake of K and Mg by mushrooms. There was no effect of the amount of organic matter in the soil noticed on the content of macronutrients (except sodium) in mushrooms. Among the studied macronutrients, none of the mushrooms accumulated Ca, while P and K were generally accumulated in the highest amounts, regardless of the species. Each of the other elements was usually accumulated at a similar level in the fruiting bodies of the species we studied. The exception was I. badia, which accumulated higher amounts of Mg compared to B. edulis and L. scabrum. Mushrooms can enrich the diet with some macronutrients, especially in P and K.

Macrofungi as a Nutraceutical Source: Promising Bioactive Compounds and Market Value

Macrofungi production and economic value have been increasing globally. The demand for macrofungi has expanded rapidly owing to their popularity among consumers, pleasant taste, and unique flavors. The presence of high quality proteins, polysaccharides, unsaturated fatty acids, minerals, triterpene sterols, and secondary metabolites makes macrofungi an important commodity. Macrofungi are well known for their ability to protect from or cure various health problems, such as immunodeficiency, cancer, inflammation, hypertension, hyperlipidemia, hypercholesterolemia, and obesity. Many studies have demonstrated their medicinal properties, supported by both in vivo and in vitro experimental studies, as well as clinical trials. Numerous bioactive compounds isolated from mushrooms, such as polysaccharides, proteins, fats, phenolic compounds, and vitamins, possess strong bioactivities. Consequently, they can be considered as an important source of nutraceuticals. Numerous edible mushrooms have been studied for their bioactivities, but only a few species have made it to the market. Many species remain to be explored. The converging trends and popularity of eastern herbal medicines, natural/organic food product preference, gut-healthy products, and positive outlook towards sports nutrition are supporting the growth in the medicinal mushroom market. The consumption of medicinal mushrooms as functional food or dietary supplement is expected to markedly increase in the future. The global medicinal mushroom market size is projected to increase by USD 13.88 billion from 2018 to 2022. The global market values of promising bioactive compounds, such as lentinan and lovastatin, are also expected to rise. With such a market growth, mushroom nutraceuticals hold to be very promising in the years to come.

Nutritional analysis and molecular characterization of hybrid mushrooms developed through intergeneric protoplast fusion between Pleurotus sajor-caju and Calocybe indica with the purpose to achieve improved strains

Two edible mushrooms Calocybe indica and Pleurotus sajor-caju were chosen as parent strains in this study to approach the concept of hybridization through the protoplast fusion technique. Protoplast fusion in presence of polyethylene glycol (PEG) was conducted between the parent strains and by further double selection screening method, six somatic hybrid lines were developed. Those fruit bodies of the hybrid lines showed phenotypic resemblance with Pleurotus sajor-caju when grown on paddy straw under favorable conditions. The hybridity of the newly developed somatic hybrid strains was established by barrage reaction, morphological traits, fruitbody parameter and, inter single sequence repeat (ISSR) profiling. One-way analysis of variance (ANOVA) was used for the analysis of phenotypic data of hybrid lines and parents. Five ISSR primers were used to generate 51 amplified DNA fragments ranged between 250 and 3000 bp in size in six hybrids and two parents with 90.19% polymorphism. Some of the hybrids contain some non-parental bands which indicate that recombination might happen in the hybrid genome hence confirming the hybridity of newly developed strains. The dendrogram was created using the Average Linkage (Between Groups) method based on ISSR profiling and genetic distance between parent-hybrids and hybrid-hybrid was analyzed by Jaccard's proximity matrix. A definite improvement in nutritional properties and biological activity was observed in the study. Due to ease in their cultivation, it can play a significant role in the rural economic development.

Family and species as determinants modulating mineral composition of selected wild-growing mushroom species

It has been known since the 1970s that differences exist in the profile of element content in wild-growing mushroom species, although knowledge of the role of mushroom species/families as determinants in the accumulation of diverse element remains limited. The aim of this study was to determine the content of 63 mineral elements, divided into six separate groups in the fruit bodies of 17 wild-growing mushroom species. The mushrooms, growing in widely ranging types of soil composition, were collected in Poland in 2018. Lepista nuda and Paralepista gilva contained not only the highest content of essential major (531 and 14,800 mg kg^-1, respectively of Ca and P) and trace elements (425 and 66.3 mg kg^-1, respectively of Fe and B) but also a high content of trace elements with a detrimental health effect (1.39 and 7.29 mg kg^-1, respectively of Tl and Ba). A high content of several elements (Al, B, Ba, Bi, Ca, Er, Fe, Mg, Mo, P, Sc, Ti or V) in L. nuda, Lepista personata, P. gilva and/or Tricholoma equestre fruit bodies belonging to the Tricholomataceae family suggests that such species may be characterised by the most effective accumulation of selected major or trace elements. On the other hand, mushrooms belonging to the Agaricaceae family (Agaricus arvensis, Coprinus comatus and Macrolepiota procera) were characterised by significant differences in the content of all determined elements jointly, which suggests that a higher content of one or several elements is mushroom species-dependent. Graphical abstract.

Fruitbody chemistry underlies the structure of endofungal bacterial communities across fungal guilds and phylogenetic groups

Eukaryote-associated microbiomes vary across host taxa and environments but the key factors underlying their diversity and structure in fungi are still poorly understood. Here we determined the structure of bacterial communities in fungal fruitbodies in relation to the main chemical characteristics in ectomycorrhizal (EcM) and saprotrophic (SAP) mushrooms as well as in the surrounding soil. Our analyses revealed significant differences in the structure of endofungal bacterial communities across fungal phylogenetic groups and to a lesser extent across fungal guilds. These variations could be partly ascribed to differences in fruitbody chemistry, particularly the carbon-to-nitrogen ratio and pH. Fungal fruitbodies appear to represent nutrient-rich islands that derive their microbiome largely from the underlying continuous soil environment, with a larger overlap of operational taxonomic units observed between SAP fruitbodies and the surrounding soil, compared with EcM fungi. In addition, bacterial taxa involved in the decomposition of organic material were relatively more abundant in SAP fruitbodies, whereas those involved in release of minerals were relatively more enriched in EcM fruitbodies. Such contrasts in patterns and underlying processes of the microbiome structure between SAP and EcM fungi provide further evidence that bacteria can support the functional roles of these fungi in terrestrial ecosystems.

Bibliometric analysis of European publications between 2001 and 2016 on concentrations of selected elements in mushrooms

This article presents a bibliometric study of 200 European publications released between 2001 and 2016, about the contamination of mushrooms by selected elements. The analysis includes figures on the type of analyte, its concentration, the species of fungi, and its country of origin. In the literature review, 492 species of mushrooms (wild-growing and cultured) found in 26 European countries and their concentration of 74 associated elements were analysed. The papers, which dealt mainly with the heavy metal (Cd, Cu, Fe, Pb, and Zn) concentrations of mushrooms, primarily came from Turkey, Poland, Spain, and the Czech Republic. More than 50% of the publications provided data about edible mushrooms. The results of the bibliometric analysis showed that over the 16 years, European research on fungal contamination by selected analytes has not lessened in popularity and is ongoing. Many of the studies underlined the need to assess the risk to human health arising from the consumption of contaminated mushrooms taken from various habitats. These results were the effect of, among other things, the strong interest in studies carried out on edible species, in which concentrations of mainly heavy metals that are dangerous to health and are marked were indicated (Cd, Pb, and Hg).

Prediction Method for Torrefied Rice Husk Based on Gray-scale Analysis

Torrefaction pretreatment has recently gained attention for the potential improvement in biomass properties. Otherwise, visible image-processing technology for analyzing properties of torrefied biomass was evaluated for possible use in the future online process control. In this study, torrefied rice husk from different torrefaction temperatures (180-330 °C) was obtained. After torrefaction, the biochar was characterized to determine the effects of torrefaction temperature on the properties, including the proximate analysis, solid yield (SY), and higher heating values. In addition, the color values, including red-green-blue (RGB) values, and grayscale (GS) of torrefied rice husk, were measured. The results show that the fixed carbon and ash increased from 17.39 to 35.13 and 7.06 to 38.41%, respectively, while volatile matters decreased from 71.47% to a minimum of 22.89% with the increase of torrefaction temperature from 105 to 330 °C. The SY remained higher than 46% even at the most severe torrefaction condition because of the high ash content and high remaining lignin. Moreover, the higher heating values of torrefied rice husk were increased from 14.80 to 17.82 MJ/kg when increased the pretreatment temperature. RGB values were decreased with the increase of torrefaction temperature. The GS analysis results show that the color of torrefied rice husk changed from yellow to brown at light torrefaction and black at severe torrefaction. GS of torrefied rice husk shows a good correlation (R = 0.9998) with torrefaction temperature. Prediction equations with higher fitting degree between GS and proximate analysis (R 2 > 0.9900), high heat values (R 2 = 0.9999), and SY (R 2 = 0.9979), which are developed to reflect the changing characteristics of torrefied rice husk. The results show that the prediction method based on GS is a promising technology to measure the properties of torrefied rice husk.

Accumulation of heavy metals by wild edible mushrooms with respect to soil substrates in the Athens metropolitan area (Greece)

Six wild edible mushroom species, Agaricus bisporus, A. bitorquis, A. gennadii, Coprinus comatus, Psathyrella candolleana and Volvopluteus gloiocephalus, were collected from the Greater Athens area (Greece), together with their soil substrates (two depth-layers) for studying bioaccumulation of heavy metals in a densely populated urban environment. Total and bioavailable Cr, Cu, Fe, Mn, Ni, Pb and Zn concentrations in soils were assessed along with their respective concentrations in mushrooms, and were evaluated in conjunction with soil properties, including K, P and Na content, CaCO₃ equivalent percentage, mechanical composition, pH and organic matter. In particular, Cu, Pb, Zn and Ni displayed a high variability in their total and bioavailable concentrations measured in the upper soil layer. Relatively high Pb and Ni contents were measured in mushrooms, while Cu, Zn, Fe and Mn concentrations varied considerably. No significant correlations were detected between total concentrations of heavy metals in soils and mushrooms, whereas bioavailable fractions for several metals were significantly correlated with their respective content in A. bisporus, C. comatus, P. candolleana and V. gloiocephalus. K, Na and P concentrations in soils were associated to the content of several metals in fruit-bodies. The effect of soil texture on metals accumulation by mushrooms was species-dependent since high correlations were found for V. gloiocephalus and C. comatus only. Interactions between metals content in fruit-bodies seem to be species-specific except for Ni vs. Fe and Mn vs. Fe, which are positively correlated in all cases. Overaccumulation of metals in fruit-bodies was established only in respect to the bioavailable fractions of Cu, Mn, Zn and Ni in soil. The levels of toxicity for Pb were exceeded in mushrooms of five species, whereas the rest of the heavy metals (with the exception of Cu) were detected at lower contents than their recommended dietary allowances or tolerable upper intake levels.

Análisis proximal y de composición mineral de cuatro especies de hongos ectomicorrízicos silvestres de la Sierra Tarahumara de Chihuahua

En Chihuahua se han registrado cerca de 500 especies de hongos macromicetos, de las que 73 son consideradas comestibles a nivel mundial. El objetivo de la presente investigación fue determinar la composición proximal y mineral de cuatro especies de hongos ectomicorrícicos comestibles de la Sierra Tarahumara en Chihuahua. Se recolectaron carpóforos de Astraeus hygrometricus, Laccaria laccata, Amanita caesarea y Pisolithus tinctorius en dos localidades del municipio de Bocoyna. A éstos se les realizó un análisis proximal para determinar el porcentaje de humedad, proteínas, grasas totales, cenizas y carbohidratos totales, así mismo se realizó un análisis de composición mineral para determinar el porcentaje de nitrógeno total (N), fósforo (P), potasio (K), calcio (Ca), magnesio (Mg), sodio (Na), cobre (Cu), hierro (Fe), manganeso (Mn) y zinc (Zn). Los resultados muestran que P. tinctorius es la especie con mayor contenido de minerales, A. hygrometricus en contenido de carbohidratos, A. caesarea en contenido de grasas y L. laccata en proteínas. De los 10 distintos minerales que fueron determinados, A. caesarea presenta el contenido más elevado en N, P, K y Zn, mientras que A. hygrometricus tiene los valores más altos de Ca y Mn. Por su parte, L. laccata muestra los contenidos más altos en Mg, Na y Cu. Finalmente, P. tinctorius resultó con los valores más altos en Fe. En general, la composición proximal y mineral de estos hongos se encuentra dentro del rango establecido para hongos comestibles, por lo que son una buena alternativa alimenticia para los habitantes de la zona.

Nutritional and antioxidant potential of some wild edible mushrooms of Nagaland, India

Mushrooms are known to mankind since early human civilization and are gaining importance because of their nutritional and medicinal properties. Till date 37 wild edible mushrooms are reported from Nagaland. In this study, nutritional analysis including total phenolics, flavonoids and antioxidant activity was done for ten popular WEM species. Total protein content was found to be high which ranged from 62.27 g/100 g (Lentinus sajor-caju) to 18.77 g/100 g (Lentinus squarrosulus var. squarrosulus); total carbohydrate content ranged from 38.44 g/100 g (Lentinula edodes) to 5.31 g/100 g (Schizophyllum commune); reducing sugar content ranged from 7.81 g/100 g (Termitomyces heimii) to 2.33 g/100 g (S. commune). Crude fiber ranged from 11.1% (A. auricula-judae) to 1.71% (L. squarrosulus) and ash content ranged from 10.66% (L. squarrosulus) to 3.12% (L. squarrosulus var. squarrosulus). The highest phenolic content was observed in L. squarrosulus (18.7 g/100 g) and highest flavonoid content was observed in L. sulphureus (9.3 g/100 g). All the ten mushroom species exhibited antioxidant activity against DPPH free radical, but highest activity was recorded in L. tigrinus (47.5 μg/ml, IC50). Hence, mushrooms are valuable natural resource to mankind and should be exploited judiciously for the betterment of society.

A Data Mining Approach to Improve Inorganic Characterization of Amanita ponderosa Mushrooms

Amanita ponderosa are wild edible mushrooms that grow in some microclimates of Iberian Peninsula. Gastronomically this species is very relevant, due to not only the traditional consumption by the rural populations but also its commercial value in gourmet markets. Mineral characterisation of edible mushrooms is extremely important for certification and commercialization processes. In this study, we evaluate the inorganic composition of Amanita ponderosa fruiting bodies (Ca, K, Mg, Na, P, Ag, Al, Ba, Cd, Cr, Cu, Fe, Mn, Pb, and Zn) and their respective soil substrates from 24 different sampling sites of the southwest Iberian Peninsula (e.g., Alentejo, Andalusia, and Extremadura). Mineral composition revealed high content in macroelements, namely, potassium, phosphorus, and magnesium. Mushrooms showed presence of important trace elements and low contents of heavy metals within the limits of RDI. Bioconcentration was observed for some macro- and microelements, such as K, Cu, Zn, Mg, P, Ag, and Cd. A. ponderosa fruiting bodies showed different inorganic profiles according to their location and results pointed out that it is possible to generate an explanatory model of segmentation, performed with data based on the inorganic composition of mushrooms and soil mineral content, showing the possibility of relating these two types of data.

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.

Evaluation of heavy metal concentrations of edible wild-grown mushrooms from China

The heavy metal contents (Co, Cu, Fe, Mn, Ni, and Zn) of eight species of wild edible mushrooms from China were determined. The analyses were performed using inductively coupled plasma atomic emission spectrophotometry after microwave digestion. The contents of Co, Cu, Fe, Mn, Ni, and Zn in caps of mushroom samples were 0.7-7.2, 16.2-70.4, 371-1315, 12.5-29.8, 7.1-58.5, and 77.8-187.4 mg kg^-1 dry matter (dm), respectively, while considerable differences were found to be 1.8-25.9, 9.8-36.3, 288-6762, 13.3-103.9, 5.9-78.7, and 38.7-118 mg kg^-1 dm for stipes. The results indicated that higher levels of Co, Fe, and Ni were found in the mushrooms samples analyzed. Zinc and manganese levels were similar to previous reports, whereas Cu was lower than literature values. Correlation analysis suggested that significant correlations were found between the minerals determined and the greatest amount of contamination is associated with Co, Mn, Ni, and Fe. The results of this study indicate that heavy metal contents in mushroom species are mainly related to the mineral resources of sampling sites.

The relationship between metal composition, phenolic acid and flavonoid content in Imleria badia from non-polluted and polluted areas

The aim of this study was to determine the elemental composition, phenolic content and composition and antioxidant properties of Imleria badia (Fr.) Vizzini (former names Boletus badius (Fr.) Fr., and Xerocomus badius (Fr.) E.-J. Gilbert) fruiting bodies collected from sites with different levels of pollution. Imleria badia was relatively tolerant to soil contamination with toxic elements and was able to grow in As, Cd, Hg and Pb concentrations exceeding 15, 2.9, 0.4 and 77 mg kg^-1, respectively. The concentration of elements in soil was reflected in the element content in I. badia. The fruiting bodies from polluted sites exhibited significantly higher content of all the analyzed elements. Among 21 individual phenolic compounds only protocatechiuc and caffeic acids, and quercetin were determined in fruiting bodies of I. badia. The differences between the concentration of the quantified phenolic compounds and the total flavonoid content in fruiting bodies of I. badia from unpolluted and polluted sites were not significant. However, the greatest total phenolic content was found in fruiting bodies from the polluted areas. The antioxidative capacity of mushrooms collected from heavily polluted sites was lower than those growing in unpolluted areas. The concentrations of some metals in soil and fruiting soil were positively correlated with phenolic content and IC₅₀.

Chemical composition and bioaccumulation ability of Boletus badius (Fr.) Fr. collected in western Poland

The aim of the study was to determine content of 17 elements (Co, Cd, Cu, Cr, Ni, Pb, Zn, Mn, Fe, Mg, Na, Ca, K, N, C, S and P) and their bioaccumulation factors (BCF) in bay bolete (Boletus badius (Fr.) Fr.) fruiting bodies (caps and stalks) and underneath soil samples collected from forest sites in lubuskie voivodeship in Poland. Forty-eight samples of Boletus badius (Fr.) Fr. fruiting bodies and the same number of underneath soil substrate samples were collected in forest sites of Sulęcin Forest District in western Poland. Copper and zinc were absorbed most strongly from soil substrate, which is performed by bioaccumulation factors (BCF_Cap/Soil = 16.57 and 11.60, respectively), wherein Pb, Co, Cr, Fe and Mn were excluded from bioaccumulation (BCF < 1.0). The mean content of Cd in caps and stalks was 1.44 ± 0.88 and 2.01 ± 1.26 mg kg^-1 dry weight, respectively and in contrary to Pb (≈3.00 ± 2.66 and 2.01 ± 1.26 mg kg^-1 d. w.) this metal is strongly accumulated from subsoil (BCF_Cap/Soil = 11.12 and BCF_Stipe/Soil = 10.83). The fruiting bodies of Boletus badius were distinguished by elevated content of Cr, Zn, Pb and Cd. Few statistically significant metal-to-metal correlations were observed. The correlation between forest habitat types and metals concentrations was also analysed. An attempt of estimation of Pb and Cd safe dose for human consumption was made.

IN CONCLUSION

mushrooms can be a good source of some micro- and macroelements, but they also contain a great amount of toxic heavy metals.

Content of Chemical Elements in Wood-Destroying Fungi

The aim of this study was to examine the content of chemical elements in the dried fruiting bodies of edible wood decaying fungi such as Honey mushrooms (Armillaria mellea), Shiitakes (Lentinus edodes) and Oyster mushrooms (Pleurotus ostreatus). Powdered samples of fungi were mineralized in a microwave digestion. Twenty-one (21) chemical elements were detected in the plasma of the device ICP-MS AGILENT 7500c by accredited methods with the aid of calibration curves. The content of individual elements varied within a considerable range. The highest contents of K, Mn, Cu and Cd were found in the fruiting bodies of Honey mushrooms (Armillaria mellea). Shiitakes (Lentinus edodes) had the highest content of B and Mo. Significant differences were found in the content of elements in the Oyster mushrooms (Pleurotus ostreatus) from Slovakia, Hungary and China. The highest content of Al was found in the Oyster mushrooms (Pleurotus ostreatus) from Hungary. The Chinese oysters had a maximum contents of Ca, Mg, Co, Pb, As and U. The Oyster mushrooms (Pleurotus ostreatus) from Lemešany (Slovakia) had the highest contents of Na, Zn, Fe, Se, Ag, Hg and Cr. The difference of chemical element content could be influenced by the genotype of the fungus and by the composition of substrate on which mushroom grow up.

Content of selected elements and low-molecular-weight organic acids in fruiting bodies of edible mushroom Boletus badius (Fr.) Fr. from unpolluted and polluted areas

The aim of the study was to (i) investigate the potential of edible mushroom Boletus badius (Fr.) Fr. to accumulate 53 elements from unpolluted acidic sandy soil and polluted alkaline flotation tailing sites in Poland, (ii) to estimate the low-molecular-weight organic acid (LMWOA) profile and contents in fruit bodies, and finally (iii) to explore the possible relationship between elements and LMWOA content in mushrooms. The content of most elements in fruiting bodies collected from the flotation tailings was significantly higher than in mushrooms from the unpolluted soils. The occurrence of elements determined in fruiting bodies of B. badius has been varied (from 0.01 mg kg^-1 for Eu, Lu, and Te up to 18,932 mg kg^-1 for K). The results established the high importance of element contents in substrate. Among ten organic acids, nine have been found in wide range: from below 0.01 mg kg^-1 for fumaric acid to 14.8 mg g^-1 for lactic acid. Lactic and succinic acids were dominant in both areas, and citric acid was also in high content in polluted area. The correlation between element contents and the individual and total content of LMWOAs was confirmed.

Fungal Transformation of Tree Stumps into a Suitable Resource for Xylophagous Beetles via Changes in Elemental Ratios

The elements present in dead pine stumps inhabited by larvae of wood-boring beetles (Stictoleptura rubra, Arhopalus rusticus and Chalcophora mariana) were analyzed over the initial (first 5 years; a chronosequence) stages of wood decay. The quantities of N, P, K, Ca, Mg, Fe, Zn, Mn, Cu and Na (but not S) increased with increases in the content of ergosterol (used as a proxy for the amount of fungal tissue). In fact, the amounts of P, N, K, Fe and Cu presented marked increases. These findings show that fungi stoichiometrically rearrange dead wood by importing externally occurring nutrients to decaying stumps. During the first years of wood decay, the ratios of C to other elements decrease substantially, but differently, for various elements, whereas the N:Fe, N:Cu, N:P and N:K ratios remain relatively stable. Therefore, the stoichiometric mismatch between xylophages and their food is greatly reduced. By changing the nutritional stoichiometry of dead wood, fungi create a nutritional niche for wood-eaters, and these changes enable the development of xylophages.

Metallic elements (Ca, Hg, Fe, K, Mg, Mn, Na, Zn) in the fruiting bodies of Boletus badius

The aim of this study was to investigate and compare the levels of eight metallic elements in the fruiting bodies of Bay Bolete (Boletus badius; current name Imleria badia) collected from ten sites in Poland to understand better the value of this popular mushroom as an organic food. Bay Bolete fruiting bodies were collected from the forest area near the towns and villages of Kętrzyn, Poniatowa, Bydgoszcz, Pelplin, Włocławek, Żuromin, Chełmno, Ełk and Wilków communities, as well as in the Augustów Primeval Forest. Elements such as Ca, Fe, K, Mg, Mn, Na and Zn were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-OES), and mercury by cold vapor atomic absorption spectrometry (CV-AAS). This made it possible to assess the nutritional value of the mushroom, as well as possible toxicological risks associated with its consumption. The results were subjected to statistical analysis (Kruskal-Wallis test, cluster analysis, principal component analysis).

Market Survey and Risk Assessment for Trace Metals in Edible Fungi and the Substrate Role in Accumulation of Heavy Metals

Levels of cadmium (Cd), arsenic (As), mercury (Hg), lead (Pb), iron (Fe), and zinc (Zn) were investigated in 285 samples of 9 species of edible fungi (Lentinus edodes, Auricularia auricula, Pleurotus ostreatus, Tremella fuciformis, Flammulina velutipes, Agrocybe chaxinggu, Armillaria mellea, Agaricus bisporus, and Pholiota nameko), which were collected from markets in Beijing, China. In addition, edible fungi and culture substrates were collected from 7 cultivation bases to examine the role of the substrate in trace metal accumulation. Trace metal concentrations were determined on a dry weight basis. Data showed that all the edible fungi contained trace metals, the levels of which varied among species, and there were significant positive correlations between trace metal (Cd, Pb, and As) concentrations in mushrooms and their substrates. The concentrations of Cd, As, Hg, Pb, Fe, and Zn in the tested fungi ranged from 0.005 to 13.8 mg/kg, nd to 1.62 mg/kg, nd to 0.506 mg/kg, 0.011 to 22.1 mg/kg, 46.3 to 2514 mg/kg, and 14.6 to 289 mg/kg, respectively. In general, concentrations of Cd, As, Hg, Pb, Fe, and Zn were relatively high in L. edodes, whereas Tremella fuciformis and P. nameko had relatively low levels of trace metals. Furthermore, the estimated weekly intake of trace metals was calculated and compared with the WHO/FAO provisional tolerable weekly intake. The estimated weekly intake of Cd, As, Hg, Pb, Fe, and Zn from consuming edible fungi was lower than the provisional tolerable weekly intake.

PRACTICAL APPLICATION

This paper reports information about trace metal concentrations in edible fungi collected from Beijing, China. This paper provides useful information for consumers and regulators about levels of trace metals in edible fungi.

Content of selected elements in Boletus badius fruiting bodies growing in extremely polluted wastes

The aim of the study was to analyse levels of 17 trace elements and 5 major minerals in 11 Boletus badius fruiting bodies able to grow in extremely polluted waste (flotation tailings) and polluted soil in southern Poland. The presented data widen the limited literature data about the abilities of wild-growing mushroom species to grow on heavily contaminated substrates. Content of elements in waste, soil and mushrooms was analysed by flame atomic absorption spectrometry (FAAS) and cold vapour atomic absorption spectrometry (CVAAS - Hg). The industrial areas differed greatly as regards the content of elements in flotation tailings and soil; therefore differences in Ag, Ba, Cd, Co, Fe, Mo, Ni, Pb, Ca, K, Mg, Na and P accumulation in mushrooms were observed. The highest contents of elements in mushrooms were observed for: As, Al, Cu and Zn (86 ± 28, 549 ± 116, 341 ± 59 and 506 ± 40 mg kg(-1) dry matter, respectively). Calculated bioconcentration factor (BCF) values were higher than 1 for Al (15.1-16.9), Fe (10.6-24.4) and Hg (10.2-16.4) only. The main value of the presented results is the fact that one of the common wild-growing mushroom species was able to grow on flotation tailings containing over 22 g kg(-1) of As and, additionally, effective accumulation of other elements was observed. In view of the high content of the majority of analysed elements in fruiting bodies, edible mushrooms from such polluted areas are nonconsumable.

Bioaccumulation of elements in three selected mushroom species from southwest Poland

The contents of 16 minerals and trace elements (Ag, As, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Pb, Pt, Ti and Zn) were analyzed in edible mushrooms (Leccinum scabrum, Boletus edulis and Boletus badius) collected in southwest Poland. Content of Co, Ni and Pb was similar in all tested mushroom species, while content of Ag, Ca, Cd, Hg and Ti was significantly higher in B. edulis than in L. scabrum and B. badius. The largest differences between these species were observed for Fe and Zn accumulation. The highest contents of these elements were noted in B. badius bodies (202 ± 88 and 137 ± 24 mg kg(-1) dry matter, respectively), lower in B. edulis (131 ± 99 and 89 ± 26 mg kg(-1) dry matter, respectively) and lowest in L. scabrum. Differences in As, Cu and Cr content between tested species were observed mainly between L. scabrum and B. badius fruiting bodies. Content of Pt was below 0.01 mg kg(-1) dry matter). In the case of Mg and Mn accumulation, differences between B. edulis and B. badius were not observed (478 and 440 mg kg(-1) dry matter for Mg and 23 and 19 mg kg(-1) dry matter for Mn), and the results showed significantly higher content of these elements than in L. scabrum bodies (312 and 10 mg kg(-1) dry matter, respectively). It is worth underlining that clear accumulation shown by the bioconcentration factor (BCF>1) observed for all three mushroom species was noted in the case of elements Ag, Cd, Co, Cu, Hg, Ni and Zn only.

How to make a beetle out of wood: multi-elemental stoichiometry of wood decay, xylophagy and fungivory

The majority of terrestrial biomass is wood, but the elemental composition of its potential consumers, xylophages, differs hugely from that of wood. This causes a severe nutritional imbalance. We studied the stoichiometric relationships of 11 elements (C, N, P, K, Ca, Mg, Fe, Zn, Mn, Cu, Na) in three species of pine-xylem-feeding insects, Stictoleptura rubra, Arhopalus rusticus (Coleoptera, Cerambycidae) and Chalcophora mariana (Coleoptera, Buprestidae), to elucidate their mechanisms of tissue growth and to match their life histories to their dietary constraints. These beetles do not differ from other Coleoptera in their absolute elemental compositions, which are approximately 1000 (N), 100 (P, Cu) and 50 (K, Na) times higher than in dead but undecayed pine wood. This discrepancy diminishes along the wood decay gradient, but the elemental concentrations remain higher by an order of magnitude in beetles than in highly decayed wood. Numerical simulation of the life history of S. rubra shows that feeding on nutrient-poor undecayed wood would extend its development time to implausible values, whereas feeding on highly decomposed wood (heavily infected with fungi) would barely balance its nutritional budget during the long development period of this species. The changes in stoichiometry indicate that the relative change in the nutrient levels in decaying wood cannot be attributed solely to carbon loss resulting from decomposer respiration: the action of fungi substantially enriches the decaying wood with nutritional elements imported from the outside of the system, making it a suitable food for wood-eating invertebrates.

Bioconcentration of mercury by mushroom Xerocomus chrysenteron from the spatially distinct locations: levels, possible intake and safety

Concentrations of mercury were determined in specimens of Red Cracking Bolete (Xerocomus chrysenteron) (Bull.) Quél. and overlying soil (0-10cm) collected from 22 spatially distributed sites in Poland during 1996-2013 to assess the potential of this species to bioconcentrate Hg and possible intake by humans. The mean Hg concentrations ranged from 80 to 630 for caps and from 28 to 380ng/g dry matter (dm) for stipes. Decrease in the potential of this mushroom species to bioconcentrate Hg both in caps and stipes was observed when the Hg content in soil substratum increased from 15 to 75-94ng/g dm. A maximum median value for bioconcentration factor (BCF) of Hg determined for caps was 18 for soil with Hg content at 15ng/g dm and decreased to 0.97-3.8 for soils that contained Hg at 37-94ng/g dm. Caps of X. chrysenteron consumed at a volume of 300g daily in a week can yield an exposure amount of Hg at 0.0168-0.1323mg (0.00024 to 0.00189mg/kg body mass); these values are well below the provisionally tolerated weekly intake (PTWI) for inorganic Hg.

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.

Lead and cadmium in mushrooms from the vicinity of two large emission sources in Slovenia

Cd and Pb contents were determined in 699 samples of fruiting bodies of 55 mushrooms species, collected in the period 2000-2007 in the vicinity of the largest Slovenian thermal power plant (the Šalek Valley) and near an abandoned lead smelter (the Upper Meža Valley). The present study is the first regarding lead and cadmium in mushrooms from those exposed areas. Therefore, there was a significant lack of prior data. Among 55 studied mushroom species 36 species are edible and important from an ecotoxicological perspective. However, the remaining non-edible species are important for bioindication and allowed us to compare our results with other studies carried out in other polluted areas in Europe. The highest contents of Cd were found in Agaricus arvensis Schff.: Fr. (117 mg/kg dw) and Agaricus silvicola L.: Fr. (67.9 mg/kg dw), while the highest contents of Pb were found in Macrolepiota procera (Scop.) Singer (53.8 mg/kg dw) and Lycoperdon perlatum Pers. (50 mg/kg dw), respectively. Considering the high contents of both metals in fruiting bodies of edible fungi, together with FAO/WHO directives on tolerable levels of weekly intake of Pb/Cd by humans, it is evident that consumption of some mushroom species originating from both study areas may pose a significant human health risk. A. arvensis Schff.: Fr., A. silvicola L.: Fr. and Cortinarius caperatus (Pers.) Fr. originating from the Šalek Valley, and Armillaria mellea Vahl. P. Kumm., Boletus edulis Bull., L. perlatum Pers., Leccinum versipelle (Fr. & Hök) Snell, and M. procera (Scop.) Singer originating from the Upper Meža Valley should not be consumed at all. Our findings are consistent with some other studies, which emphasized that mushrooms from heavily polluted areas, such as in the vicinity of smelters, accumulate extremely high amounts of metals, and should therefore be omitted from human consumption.

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

The aim of this study was to evaluate Cd, Co, Cu, Hg, Ni, Pb, Sr and Zn accumulation in six edible mushroom species and to assess their risk and benefits to human consumers. Mushrooms (Leccinium aurantiacum, Xerocomus badius, Lactarius deliciosus, Boletus edulis, Cantharellus cibarius and Suillus luteus) were collected from selected regions of Poland during 1990-2010. The highest diversity between studied mushroom species was observed in terms of Cu and Zn accumulation. Significant differences in the accumulation efficiency were found among the six mushroom species examined. The most efficient were Boletus edulis (Cd and Hg), Suillus luteus (Cu and Sr), and Lactarius deliciosus (Pb and Zn). In the case of Co and Ni, the most effective were Xerocomus badius and Leccinium aurantiacum, respectively. The calculated bioconcentration factor (BCF) values of Cd, Cu, Hg, Sr and Zn were > 1 for all species in this study while Co, Ni and Pb usually were bioexcluded (BCF < 1). Additionally, based on the calculated daily intake rates of trace elements determined it can be concluded that occasional consumption of fruiting bodies of L. aurantiacum, X. badius, L. deliciosus, B. edulis, C. cibarius and S. luteus collected in Poland is safe and this finding largely agrees with results from recent studies by other authors.

Accumulation of elements by edible mushroom species II. A comparison of aluminium, barium and nutritional element contents

The aim of the study was to compare accumulation efficiency of Al, Ba and nutritional elements (Ca, Fe, K, Mg, Mn, Na) exhibited by six edible mushrooms collected in particular regions of Poland during the last 20 years. The studied mushroom species were Boletus edulis, Cantharellus cibarius, Lactarius deliciosus, Leccinum aurantiacum, Suillus luteus and Xerocomus badius. The highest and the lowest concentrations of the elements in tested mushroom species were 11 - 410, 34 - 337, 16785 - 34600, 140 - 607, 12 - 75 and 16 - 143 mg kg(-1)d.m., respectively. The highest average concentrations of Al, Mg and Mn were observed in Suillus luteus fruiting bodies, while for Ba, Ca, K and Na it was in Lactarius deliciosus. BCF >1 was found for K and Mg in all tested mushroom species and additionally for the highest Ca and Na concentrations of all tested mushroom species except for C. cibarius and S. luteus, respectively. For the other tested elements (Al, Ba, Fe and Mn) BCF values < 1 were recorded.

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

This article reviews and updates data on macro and trace elements and radionuclides in edible wild-grown and cultivated mushrooms. A huge biodiversity of mushrooms and spread of certain species over different continents makes the study on their multi-element constituents highly challenging. A few edible mushrooms are widely cultivated and efforts are on to employ them (largely Agaricus spp., Pleurotus spp., and Lentinula edodes) in the production of selenium-enriched food (mushrooms) or nutraceuticals (by using mycelia) and less on species used by traditional medicine, e.g., Ganoderma lucidum. There are also attempts to enrich mushrooms with other elements than Se and a good example is enrichment with lithium. Since minerals of nutritional value are common constituents of mushrooms collected from natural habitats, the problem is however their co-occurrence with some hazardous elements including Cd, Pb, Hg, Ag, As, and radionuclides. Discussed is also the problem of erroneous data on mineral compounds determined in mushrooms.

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

This article reviews and updates data on macro and trace elements and radionuclides in edible wild-grown and cultivated mushrooms. A huge biodiversity of mushrooms and spread of certain species over different continents makes the study on their multi-element constituents highly challenging. A few edible mushrooms are widely cultivated and efforts are on to employ them (largely Agaricus spp., Pleurotus spp., and Lentinula edodes) in the production of selenium-enriched food (mushrooms) or nutraceuticals (by using mycelia) and less on species used by traditional medicine, e.g., Ganoderma lucidum. There are also attempts to enrich mushrooms with other elements than Se and a good example is enrichment with lithium. Since minerals of nutritional value are common constituents of mushrooms collected from natural habitats, the problem is however their co-occurrence with some hazardous elements including Cd, Pb, Hg, Ag, As, and radionuclides. Discussed is also the problem of erroneous data on mineral compounds determined in mushrooms.

The trace element content of top-soil and wild edible mushroom samples collected in Tuscany, Italy

The amount of the trace elements As, Ba, Cd, Cr, Cu, Hg, Li, Mn, Ni, Pb, Rb, Se, Sr, and Zn was measured in top soils and edible mushrooms, Boletus edulis, Macrolepiota procera, collected at five distinct green microhabitats inside the Lucca province, North-Central Italy (years 2008-2009). Results showed a top soil element content within the Italian statutory limits. Concerning the amount of mushroom elements, we observed significant species-differences obtaining higher levels of Ni, Rb, and Se in B. edulis or As, Pb, Cu in M. procera. Bioaccumulation factors (BCFs: element in mushroom/element in soil) resulted species-dependent and element-selective: in particular, B. edulis preferentially accumulated Se (BCFs varying from 14 to 153), while M. procera mainly concentrated Cu (BCFs varying from 5 to 15). As well, both species displayed between-site BCF differences. By a multivariate principal component approach, cluster analysis (CA), we could resolve two main clusters of soil element composition, corresponding to the most ecologically divergent sites. Besides, CA showed no cluster relating to element contents of B. edulis at the different collection sites, while a separation in groups was found for M. procera composition with respect to harvesting locations, suggesting uptake systems, in this saprotrophic species, sensitive to microhabitat. Regarding consumer safety, Cd, Hg, Pb levels resulted sometime relevant in present samples, never reaching values from current literature on mushrooms collected in urban-polluted areas. Our findings encourage a deeper assessment of the molecular mechanisms of metal intake by edible mushrooms, encompassing genetic biochemical and geo-ecological variables, with particular awareness to element bioavailability in soils and fungi.

The bioaccumulation and translocation of Fe, Zn, and Cu in species of mushrooms from Russula genus

INTRODUCTION

Many previous studies revealed a high ability of mushrooms to accumulate heavy metals from environment. This paper concerns the capacity of some wild macromycetes belonging to Russula genus to accumulate heavy metals in natural condition of pH (between 6.5 and 6.8) and the pattern of metal translocation in the fruiting body.

MATERIALS AND METHODS

The studied Russula species are Russula virescens, Russula cyanoxantha, Russula foetens, and Russula nigrescens, which were harvested from forestry ecosystem from South Romania. The metal concentration in mushrooms and their substrate was established by EDXRF method.

RESULTS AND DISCUSSION

The concentrations of iron (Fe), zinc (Zn), and copper (Cu) in the fruiting body depends on species and vary between 58.83-340.34, 19.70-99.62, and 5.03-9.37 mg/kg for Fe, Zn, and Cu, respectively. The bioaccumulation factor has subunit values for the three studied trace metals, which show the low capacity of these species of mushrooms to accumulate metals if the concentrations in soil increase over the normal threshold for these elements. The high values of translocation factor demonstrate the mobility of Fe, Zn, and Cu in the studied mushrooms.

The determination of molybdenum in selected mushrooms by stripping voltammetry

The highly sensitive method of adsorptive stripping voltammetry (AdSV), with differential pulse steps, was performed at a mercury film electrode and has been applied here for the determination of trace molybdenum content in selected wild mushrooms. Fruiting body caps of 12 selected macrofungi species from Basidiomycetes have been investigated. Molybdenum content of investigated samples was determined in the range of 0.006 to 0.38 mg kg−1 of dry matter. The highest value of molybdenum content was found in Leccinum rufum and the lowest in Lactarius deliciosus.