The risk of high mercury accumulation in edible mushrooms cultivated on contaminated substrates

The Assessment of Mercury Concentrations in Two Species of Edible Forest Mushrooms, Aureoboletus projectellus and Imleria badia, and Their Impact on Consumers' Health

In recent years, the consumption of wild mushrooms in Central Europe has significantly increased. These mushrooms are increasingly recognized as a nutritious, low-calorie, and environmentally friendly food option. They are a valuable source of protein and are rich in vitamins and minerals; however, they can also accumulate toxic elements that may pose risks to human health. This study examined the mercury concentrations in the fruiting bodies of two edible forest mushroom species: Aureoboletus projectellus and Imleria badia. This study took into account the distribution of Hg in the two morphological parts of mushroom fruiting bodies-the caps and the stipes. The total mercury content of the mushroom samples was analyzed using an AMA-254 analyzer. Both mushroom species exhibited higher mercury concentrations in their caps than in their stipes, with levels measuring 0.048 mg·kg-1 dry matter (DM) for Aureoboletus projectellus and 0.055 mg·kg-1 DM for Imleria badia. The mercury content in the stipes was 0.032 mg·kg-1 DM for Aureoboletus projectellus and 0.025 mg·kg-1 DM for Imleria badia. The results obtained indicate that these species do not pose a health risk to consumers in terms of Hg content and can be a valuable addition to the human diet. They are also an indicator of the quality of the forest environment of the central coast of Poland, which should be considered free of mercury pollution.

Extraction, purification, structural characteristics, biological activities, modifications, and applications from Hericium erinaceus polysaccharides: A review

Hericium erinaceus (Bull.) Pers. is a respected medicinal and edible fungus known for its outstanding nutritional profile. In traditional Chinese medicine, it is viewed as a valuable medicinal resource offering various benefits, such as liver protection, spleen fortification, stomach nourishment, and improved digestion. The primary active ingredient, H. erinaceus polysaccharides (HEPs), exhibits diverse biological activities, including immunomodulatory, gastrointestinal protective, regulation of intestinal flora, anti-Alzheimer's, and antioxidant activities. These activities underscore the significant potential of HEPs for treating various diseases and developing HEPs-based pharmaceuticals. For instance, HEPs can exert immunomodulatory effects through the TLR4/NFκB/MyD88/MAPK/PI3K/Akt signaling pathways. Additionally, HEPs achieve immunomodulatory, gastrointestinal protection, and anti-inflammatory and anti-cancer effects by modulating intestinal microbiota. This review systematically summarizes the past five years' research on the extraction, purification, structural characteristics, pharmacological properties, structure-activity relationships, structural modifications, toxicological effects, and potential applications of HEPs. It highlights the diverse biological activities of HEPs in vivo and in vitro and discusses structural modification methods and their broad application prospects in food, medicine, industry, and other fields. These studies will enhance the understanding of HEPs and promote further exploration and innovation in the field of biological activity research and the development of potential applications.

Mycoremediation of Flotation Tailings with Agaricus bisporus

Due to their enzymatic and bioaccumulation faculties the use of macromycetes for the decontamination of polluted matrices seems reasonable for bioremediation. For this reason, the aim of our study was to evaluate the mycoremediation ability of Agaricus bisporus cultivated on compost mixed with flotation tailings in different quantities (1, 5, 10, 15, and 20% addition). The biomass of the fruit bodies and the content of 51 major and trace elements were determined. Cultivation of A. bisporus in compost moderately polluted with flotation tailings yielded significantly lower (the first flush) and higher (the second flush) biomass of fruit bodies, compared with the control treatment. The presence of toxic trace elements did not cause any visible adverse symptoms for A. bisporus. Increasing the addition of flotation tailings to the compost induced an elevated level of most determined elements. A significant increase in rare earth elements (both flushes) and platinum group elements (first flush only) was observed. The opposite situation was recorded for major essential elements, except for Na and Mg in A. bisporus from the second flush under the most enriched compost (20%). Nevertheless, calculated bioaccumulation factor values showed a selective accumulation capacity—limited for toxic elements (except for Ag, As, and Cd) and the effective accumulation of B, Cu, K, and Se. The obtained results confirmed that A. bisporus can be used for practical application in mycoremediation in the industry although this must be preceded by larger-scale tests. This application seems to be the most favorable for media contaminated with selected elements, whose absorption by fruiting bodies is the most efficient.

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.

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).

Mushroom Quality Related with Various Substrates' Bioaccumulation and Translocation of Heavy Metals

Mushrooms are popular due to the nutrition contents in the fruit bodies and are relatively easy to cultivate. Mushrooms from the white-rot fungi group can be cultivated on agricultural biomass such as sawdust, paddy straw, wheat straw, oil palm frond, oil palm empty fruit bunches, oil palm bark, corn silage, corn cobs, banana leaves, coconut husk, pineapple peel, pineapple leaves, cotton stalk, sugarcane bagasse and various other agricultural biomass. Mushrooms are exceptional decomposers that play important roles in the food web to balance the ecosystems. They can uptake various minerals, including essential and non-essential minerals provided by the substrates. However, the agricultural biomass used for mushroom cultivation is sometimes polluted by heavy metals because of the increased anthropogenic activities occurring in line with urbanisation. Due to their role in mycoremediation, the mushrooms also absorb pollutants from the substrates into their fruit bodies. This article reviews the sources of agricultural biomass for mushroom cultivation that could track how the environmental heavy metals are accumulated and translocated into mushroom fruit bodies. This review also discusses the possible health risks from prolonged uptakes of heavy metal-contaminated mushrooms to highlight the importance of early contaminants’ detection for food security.

The importance of Cu × Pb interactions to Lentinula edodes yield, major/trace elements accumulation and antioxidants

Due to the use of various substrates in the production of edible mushrooms which may contain metals, including Cu and Pb, it is important to understand the influence of mutual interactions between them in the process of their accumulation in fruit bodies. For this reason, the effects of Cu, Pb, and Cu × Pb on yield, accumulation of five major elements (Ca, K, Mg, Na and P), trace elements (Cu, Pb and Fe) and some bioactive compounds in Lentinula edodes fruit bodies were studied. Both the metals were added in doses of 0.1 and 0.5 mM (Cu0.1, Cu0.5, Pb0.1, Pb0.5 and their combinations). The addition of the metals resulted in a reduction in size, amount and finally yield of fruit bodies. Depending on the presence of Cu and or Pb and their concentration in the substrate, both antagonism and synergism may occur. The influence on the accumulation of other determining elements was also recorded. Among phenolic compounds, phenolic acids and flavonoids were detected. 2,5-Dihydroxybenzoic acid dominated in fruit bodies in the control variant, Pb0.1, Pb0.5 and all experimental variants enriched with Cu + Pb, while gallic acid was the major phenolic after Cu0.1 and Cu0.5 addition. Only protocatechuic acid content increased in all combinations. A significant decrease of all aliphatic acid contents in comparison to the control variant was observed in the Cu0.1 and Pb0.1 variants. Significant stimulation of aliphatic acid synthesis was recorded in Cu0.5 and Pb0.5 variants and in the mixture of both the metals. The additions pointed to the possible role of the determined molecules in detoxification mechanisms.

Occurrence, behavior, and human exposure and health risks of potentially toxic elements in edible mushrooms with focus on Africa

Understanding the occurrence, behavior, and fate of potentially toxic elements (PTEs) in the substrate-mushroom-human nexus is critical for assessing and mitigating their human health risks. In this review, we (1) summarized the nature, sources, and biogeochemical behavior of PTEs in the substrate-mushroom systems; (2) discussed the occurrence, exposure, and human health risks of PTEs in mushrooms with emphasis on African geological hotspots such as metalliferous and highly mineralized substrates; (3) developed a 10-step conceptual framework for identifying, assessing, and mitigating the human health risks of PTEs in mushrooms, and highlight future directions. High human exposure risks potentially exist in Africa due to the following: (1) widespread consumption of mushrooms from various metalliferrous and highly mineralized substrates such as serpentines and mine waste dumps, (2) inadequate and poorly enforced environmental health and food safety regulations and policies, (3) limited environmental and human health monitoring data, and (4) potential synergistic interactions among PTEs in mushrooms and human health stressors such as a high burden of human diseases and infections. Although the human health effects of individual PTEs are well known, scientific evidence linking human health risk to PTEs in mushrooms remains weak. A framework for risk assessment and mitigation, and future research directions are recommended.

Toxicological risks and nutritional value of wild edible mushroom species -a half-century monitoring study

The content of major- and trace elements in wild-growing mushrooms has been subject to numerous studies, but the data on long-term trends in this regard are scarce. The aim of research was to determine the content of 34 elements in four edible mushroom species Boletus edulis, Imleria badia, Leccinum scabrum and Macrolepiota procera, and associated soil collected from Polish forests between 1974 and 2019. As initially hypothesized, the element concentration in the studied soil revealed an increasing trend and was positively correlated with their levels found in fruit bodies. Bioconcentrafion Factor values exceeding 1 were documented for all mushroom species for K, P, Ag, Cd, Cu, Hg, and Zn. When compared to the Adequate Intakes, all the mushroom species were found to be a good dietary source of K, P, and Zn (range of 6260-8690, 6260-8690 and 97-135 mg kg^-1 dry weight (dw), respectively), and B. edulis and I. badia a moderate source of Fe (mean 71.5 and 76.5 mg kg^-1 dw, respectively), B. edulis of Mn and Mo (mean 20.0 and 0.42 mg kg^-1 dw, respectively), while L. scabrum and M. procera a source of Cu. Consumption of the studied mushrooms would not lead to significant exposure to Al, As, Cr, or Ni. Considering that wild mushrooms will continue to be collected in Poland, one should bear in mind that they are a limited source of minerals in the human diet while their frequent, regular consumption, associated with exposure to selected toxic elements, should not be recommended.

Mineral composition of elements in wood-growing mushroom species collected from of two regions of Poland

The study monitored the content of 55 elements in 21 wood-growing mushroom species collected between 2013 and 2019 from Lower and Upper Silesia in Poland. Only 27 of the elements (Ag, Al, Ba, Ca, Cd, Cu, Fe, In, K, La, Mg, Mn, Na, Nd, Ni, P, Pb, Pr, Pt, Rh, Sr, Ti, Tm, V, Y, Zn, and Zr) were detected in all mushroom species, while others (As, Au, B, Be, Bi, Ce, Co, Cr, Dy, Er, Eu, Ga, Gd, Ge, Hf, Ho, Ir, Li, Lu, Mo, Os, Pb, Rb, Re, Ru, Sb, Sc, Se, Sm, Tb, Te, Th, Tl, Tm, U, and Yb) were below the limit of detection in the fruit bodies of at least one species. Wide ranges for major elements in the whole population of all the mushroom species were as follows: 15.4-470 (Ca), 6580-44,600 (K), 314-2150 (Mg), 38.0-319 (Na), and 1100-15,500 (P) mg kg^-1 dm, respectively. The rank sum revealed that M. giganteus fruit bodies were the most enriched with all detectable elements, while A. mellea had the lowest content of the majority of elements. Mushrooms belonging to the Hymenochaetaceae family were characterized as some of the most enriched with the studied elements, while mushrooms of the Fomitopsidaceae family had the lowest content of elements. Similarities as well as differences between the obtained results and the available literature data confirm the important role of both mushroom species and the tree on which the fungus has grown.

Changes in mineral composition of six strains of Pleurotus after substrate modifications with different share of nitrogen forms

The chemical characteristics of substrate are one the most significant factors influencing the growth and development of cultivated mushroom species. The aim of this study was to determine the mineral composition of six Pleurotus species (P. cistidiosus, P. djamor, P. ostreatus, P. ostreatus var. florida, P. pulmonarius and P. sajor-caju) growing on three wheat straw substrates with the addition of agricultural fertilizer rich in ammonium and with addition of salt solution rich in nitrates. Significant differences in the concentration of Al, Ca, Cu, Ir, Ni, Ru, Sn and Te were observed in all substrates used in this experiment. Cultivation on chemically-enriched substrates did not result in changes in yield with the exception of P. sajor-caju, which had a lower yield when grown on ammonium-rich substrate. No macroscopic alterations in fruit bodies were observed for any species regardless of the applied substrate. A higher concentration of selected elements was not correlated with their higher content in particular mushroom species, or such a relationship was present only in selected mushroom species. The efficiency of element accumulation depends on their concentration in the substrate (positive values of rs), although the mushroom species and the nitrogen form concentration may also have a significant impact (negative rs values). The obtained results show that cultivation of different Pleurotus strains on substrates enriched with a different share of ammonium and nitrate may cause changes in their mineral composition in spite of the similarity in the concentration of the majority elements in substrates.

Occurrence, distribution and estimated intake of mercury and selenium from sclerotia of the medicinal fungus Wolfiporia cocos from China

The contamination and distribution of mercury and selenium in the Chinese medicinal fungus Wolfiporia cocos was investigated. The sclerotial mercury concentrations ranged from 0.0043 to 0.027 mg kg¹ dry biomass (db) in the inner white part and 0.019-0.074 mg kg^-1 db in the shell (outer part), while selenium concentrations ranged from < 0.00048 to 0.0040 mg kg^-1 db (white) and 0.0034-0.038 mg kg^-1 db (shell). Positive correlations were found for mercury, as well as for mercury and selenium but they were not consistent for both morphological parts. Mercury concentrations exceeded selenium in 16 of 17 white part pools (molar quotient 0.53 to > 10) and in 11 of 17 shell pools (quotient 0.37 to 3.2). The estimated maximal exposure to mercury contained in sclerotial products based on 45 g per capita daily intake for a 60 kg individual over one week, was 0.000020 mg kg^-1 body mass (bm; white) and 0.000055 mg kg^-1 bm (shell) on a daily basis, and 0.00014 mg kg^-1 bm (white) and 0.00039 mg kg^-1 bm (shell) on a weekly basis. Relative to mercury, the corresponding intake rates of selenium were considered very low, i.e., they averaged on a daily basis at 0.00075 μg kg^-1 bm (white) and 0.0097 μg kg^-1 bm (shell) with maximum intake at 0.0030 μg kg^-1 bm (white) and 0.028 μg kg^-1 bm (shell).

Doxycycline transfer from substrate to white button mushroom (Agaricus bisporus) and assessment of the potential consumer exposure

The presence of antibiotic residues in the food chain may pose a serious risk to human health. Locating and evaluating new sources of consumer exposure to antibiotic residues in food is a very important element of health protection. The possibility of doxycycline uptake from the substrate for mushroom cultivation by the white button mushroom (Agaricus bisporus) fruit body was investigated. Mushrooms were experimentally cultivated on substrate contaminated with 8 different doxycycline concentrations in substrate and analyte concentrations in mushroom samples were measured using ultra-high performance liquid chromatography - triple quadrupole tandem mass spectrometry (UHPLC-MS/MS) The obtained results clearly indicated that doxycycline transfers from contaminated substrate to mushrooms at concentrations ranging from 0.87 to 72.3 µg/kg, depending on substrate contamination concentration level and order of harvesting.

Worldwide basket survey of multielemental composition of white button mushroom Agaricus bisporus

Agaricus bisporus is the most commonly cultivated and consumed mushroom species. The aim of this study was to compare the profile of macro- and trace elements in A. bisporus fruit bodies produced commercially in 19 countries in 2018 and distributed worldwide (32 analyzed objects). Trace elements with unknown biological roles were also determined. The content of 36 elements (of 70 taken into account) revealed significant differences among the analyzed objects. Contents of Ca, K, Mg, Na and S varied in wide ranges of 425-2430, 12740-40940, 610-3240, 98-430 and 1030-2650 mg kg^-1 dw, respectively. The fruit bodies were characterized by a generally similar content of trace elements with some clear exceptions. Rankings of the objects according to the decreased amount of macroelements, trace elements and all elements jointly, show that mushrooms are significantly diverse as regards the content of particular elements of the mentioned group. The analyzed fruit bodies displayed a relatively high content of Ca, Mo and Se, and a high K/Na ratio. Regardless of origin, A. bisporus did not constitute a source of significant levels of Al, Cd or rare earth elements. An increased level of As and Pb in mushrooms from several producers indicates a need for additional measures to reduce potential dietary exposures to these toxicants.

Is the Yellow Knight Mushroom Edible or Not? A Systematic Review and Critical Viewpoints on the Toxicity of Tricholoma equestre

There is no scientific consensus regarding the safety of the Yellow Knight mushroom Tricholoma equestre (L.) P.Kumm. Following reports of cases of intoxication involving effects such as rhabdomyolysis, and supportive observations from in vivo experimental models, T. equestre is considered as a poisonous mushroom in some countries while in others it is still widely collected from the wild and consumed every year. In this paper, we review all the available information on T. equestre including its morphological and molecular characterization, nutritional value, levels of contaminants observed in fruiting bodies, the possibility of mistake with species that are morphologically similar, and the in vivo data on safety and cases of human intoxication. Based on available data, it is suggested that T. equestre cannot be considered as a toxic species and does not appear to exhibit any greater health threat than other mushroom species currently considered as edible. More care should be taken when reporting cases of human poisoning to fully identify T. equestre as the causative agent and to exclude a number of interfering factors. Specific guidelines for reporting future cases of poisoning with T. equestre are outlined in this paper. Any future research involving T. equestre should present the results of molecular phylogenetic analyses.

Arsenic and Other Elemental Concentrations in Mushrooms from Bangladesh: Health Risks

Mushroom cultivation has been increasing rapidly in Bangladesh. Arsenic (As) toxicity is widespread in the world and Bangladesh faces the greatest havoc due to this calamity. Rice is the staple food in Bangladesh and among all the crops grown, it is considered to be the main cause of As poisoning to its population after drinking water. Consequently, rice straw, an important growing medium of mushrooms in Bangladesh, is known to have high As content. The objective of this study was, therefore, to determine the concentrations of As in mushrooms cultivated in Bangladesh and to assess the health risk as well. It also considered other elements, including Cd, Cr, Co, Cu, Pb, Mn, Hg, Ni, and Zn concentrations in mushrooms from Bangladesh. The mean concentrations (mg/kg) of As, Cd, Cr, Co, Cu, Pb, Mn, Hg, Ni, and Zn in mushrooms were 0.51, 0.38, 0.28, 0.01, 13.7, 0.31, 11.7, 0.12, 0.28, and 53.5, respectively. Based on the dietary intake of mushrooms, the weekly intakes of As, Cd, Cr, Co, Cu, Pb, Mn, Hg, Ni, and Zn from mushrooms for adults were 0.0042, 0.0030, 0.0024, 0.0001, 0.1125, 0.0019, 0.1116, 0.0011, 0.0023, and 0.4734 mg, respectively. Due to the low concentrations of As and other trace elements observed in mushrooms from Bangladesh, as well as relatively lower consumption of this food in people’s diet, it can be inferred that consumption of the species of mushrooms analysed will cause no toxicological risk.