Mercury in edible mushrooms and underlying soil: bioconcentration factors and toxicological risk

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.

Fungal species and element type modulate the effects of environmental factors on the concentration of potentially toxic elements in mushrooms

Numerous edible mushrooms accumulate Potentially Toxic Elements (PTE), such as cadmium, mercury, and lead, within their sporocarps. This accumulation poses a potential risk of poisoning for humans and is influenced by factors such as the mushroom species, type of element, and the level of industrialization in the region. In our study, we investigated how soil and tree stand characteristics, including C/N ratio, pH, tree diversity, canopy cover, and the proportion of deciduous trees, influence PTE concentration in mushrooms. We collected edible mushrooms from 20 plots situated in the Białowieża Primeval Forest, one of Europe's best-preserved lowland forests. Plots varied in terms of tree species composition, with other factors minimized. We used ICP-MS (Inductively Coupled Plasma - Mass Spectrometry) technique to analyze the concentration of eight PTE (Ag, As, Cd, Ni, Pb, Sb, Sr, Tl) in eight edible mushroom species (M.procera, L.perlatum, R. butyracea, R.cyanoxantha, R.heterophylla, L.vellereus, A.mellea, and Xerocomellus chrysenteron). Our research revealed that the presence of the effect of specific factors on concentration of PTE and its direction depends on mushroom species and type of PTE. The proportion of deciduous tree species and pH of the topsoil layer emerged as the most influential factors affecting PTE concentration in mushroom samples. Tree species richness in the canopy layer did not affect PTE concentration in mushrooms, except for the concentration of Pb in X. chrysenteron. We observed a consistent profile of PTE concentration in mushrooms with similar ecological roles (ectomycorrhizal, saprotrophic, parasite mushrooms) and from comparable phylogenetic affinities.

Effects of legacy mining on mercury concentrations in conifer needles and mushrooms in northern Palatinate, Germany

Due to integrated pollution prevention and control measures and the reduced burning of coal, air concentrations of mercury (Hg0) are currently levelling off. In the future, however, evasion from land surfaces will probably reverse this trend. Reasons are the rising temperatures and the loss of forest cover caused by calamities, droughts, storms and wildfires. Plant leaves constitute an important matrix for the accumulation of gaseous mercury and uptake and re-volatilisation by plants depends on the species, the vitality and the age and morphology of leaf organs. It has been shown that older conifer needles show higher concentrations than young needles and Hg accumulation is increasing throughout the season. In present study, we collected branches from Norway Spruce (Picea abies) in a former cinnabar mining region in Northern Palatinate, where artisanal and small-scale mining left innumerable waste dumps. While mining, smelting and processing of the ores were terminated during WWII, high total mercury concentrations remained in the top soils locally, with presumably only small fractions being plant available. In the lab, up to seven needle age classes were analysed. 1000 needle weights increased with age and as expected, also the Hg concentrations were elevated in the older needles. Needle concentrations were higher than those reported from other national biomonitoring programs confirming the regional imprint from legacy mercury. To complement our biomonitoring study, we collected edible mushrooms in former mining areas. Hg concentrations in most samples exceeded the EU maximum residue levels (MRL), while only a few broke the existing cadmium and lead limits. Tolerable weekly intake (TWI) for inorganic mercury would be surpassed with the consumption of a small portion of mushrooms. Further studies should be performed on the outgassing of Hg from mine wastes and the incorporation of Hg in the local food web, including its methylation and biomagnification.

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.

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.

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.

A method for the analysis of methylmercury and total Hg in fungal matrices

The aim of the study was to develop an efficient method for the determination of monomethyl-mercury (MeHg) and total mercury (THg) content in materials such as fungal sporocarps and sclerotia. Certified Reference Materials (CRMs) with the assigned values of MeHg and THg as well as the control materials (dried mushrooms) with known content of THg were evaluated for method validation. Recovery of MeHg from reference materials was at the following levels: from tuna fish at 87.0 ± 2.3% (THg at 101.9 ± 1.2%), from fish protein at 99.4 ± 1.3% (THg at 92.70 ± 0.41%), and from dogfish liver at 96.45 ± 0.73%. Recovery of THg from the fungal control material CS-M-5 was at 104.01 ± 0.60% (contribution of MeHg in THg content was at 6.2%), from CS-M-4 at 101.1 ± 2.0% (contribution at 3.2%), from CS-M-3 at 100.55 ± 0.67% (contribution at 0.6%), and from CS-M-2 at 101.5 ± 2.7% (contribution at 3.7%). The content of MeHg in randomly selected wild fungi and their morphological parts was in the range from 0.006 to 0.173 mg kg^-1 dry weight (dw). In the case of THg, the concentration values were in the range from 0.0108 to 10.27 mg kg^-1 dw. The MeHg content in the control materials with the assigned THg values was determined. Since the control materials play an important role in all elements of the quality assurance system of measurement results, they can be used to analyse MeHg as the first control material for fungi. KEY POINTS: • An extraction procedure for MeHg analysis in fungi was developed and optimized. • Recovery of MeHg from the certified reference non-fungal materials was > 87%. • Fungal control materials with assigned THg concentration can serve also for MeHg analysis.

Health Risk Assessment and Multivariate Statistical Analysis of Heavy Metals in Vegetables of Khyber Pakhtunkhwa Region, Pakistan

The level of heavy metals in vegetables grown in soil irrigated with various sources of water and the health risks associated with the consumption of these vegetables were assessed in this study. Samples of water, soil, and vegetables were collected from farmer fields. After digestion in acidic solution, analytical measurements were made using an atomic absorption spectrophotometer. The mean concentration of Pb, Cr, Cd, Cu, Zn, Ni, Fe, and Mn in the soil of two sampling area were in the range from 60.00 to 84.00 mg kg^-1, 68.00 to 98.00 mg kg^-1, 1.60 to 2.60 mg kg^-1, 26.10 to 33.20 mg kg^-1, 22.60 to 30.80 mg kg^-1, 50.10 to 78.30 mg kg^-1, 420.00 to 471.00 mg kg^-1, and 270.20 to 340.50 mg kg^-1, respectively. Heavy metals in soil varied significantly at (P ≤ 0.001) among sampling area. The nine heavy metals were divided into two clusters for wastewater and soil, according to cluster analysis. The number of variables was reduced using principal component analysis, which yielded three latent factors, one for wastewater and one for soil. Pb, Cr, Cd, Cu, Zn, Ni, Fe, and Mn concentrations were significantly higher at P ≤ 0.001 in nine vegetables grown on soil irrigated with untreated wastewater than in vegetables grown on fresh-tube well-water-irrigated soil. The health risks associated with metal intake were assessed using the estimated daily intake of metals (EDIM), hazard quotients (HQs), and hazard index (HI). The rates of metal transfer to vegetables have been determined. Except for Pb and Cd, all of the elements' EDMI values were found to be lower than their RfD values. The corresponding HRI values of metals in the various vegetables were found to be below 1, implying that vegetable consumption in the studied region poses no carcinogenic risk. Constant determination of heavy metals in all fruits and vegetables is essential for the assessment of health risks associated with dietary metal exposure. The study has provided valuable information to the general public about the use of wastewater for irrigation of vegetables.

Exposure to Essential and Toxic Elements via Consumption of Agaricaceae, Amanitaceae, Boletaceae, and Russulaceae Mushrooms from Southern Spain and Northern Morocco

The demand and interest in mushrooms, both cultivated and wild, has increased among consumers in recent years due to a better understanding of the benefits of this food. However, the ability of wild edible mushrooms to accumulate essential and toxic elements is well documented. In this study, a total of eight metallic elements and metalloids (chromium (Cr), arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb), copper (Cu), zinc (Zn), and selenium (Se)) were determined by ICP-MS in five wild edible mushroom species (Agaricus silvicola, Amanita caesarea, Boletus aereus, Boletus edulis, and Russula cyanoxantha) collected in southern Spain and northern Morocco. Overall, Zn was found to be the predominant element among the studied species, followed by Cu and Se. The multivariate analysis suggested that considerable differences exist in the uptake of the essential and toxic elements determined, linked to species-intrinsic factors. Furthermore, the highest Estimated Daily Intake of Metals (EDIM) values obtained were observed for Zn. The Health Risk Index (HRI) assessment for all the mushroom species studied showed a Hg-related cause of concern due to the frequent consumption of around 300 g of fresh mushrooms per day during the mushrooming season.

Influence of beech and spruce on potentially toxic elements-related health risk of edible mushrooms growing on unpolluted forest soils

Atmospheric deposition-related potentially toxic elements (PTEs) can contaminate mountain forest ecosystems. The influence of tree species is being increasingly recognised as an important factor in the deposition loads in forest soils. However, relevant modelling studies about the forest pollution with PTEs, concerning the tree species composition, are lacking. The aim of this study was to evaluate the effect of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) H. Karst.) on soil and mushroom pollution and the associated health risks to define their significance for pollution modelling. Therefore, topsoil samples and samples of eight edible mushroom species were taken from 51 mature beech- and spruce-dominated stands. The results showed that forest composition had an indirect influence on the PTEs contents in the topsoil; it significantly differentiated the relationship between PTEs and soil C as the beech stands showed significantly increasing PTEs content with increasing C content. Despite the absence of soil pollution, above-limit levels of Cd and Zn were found in mushrooms. The total content of PTEs in mushrooms posed a potential health risk to consumers in 82% of the samples. The most Cd-contaminated and potentially the riskiest species for consumption was Xerocomellus pruinatus (Fr. and Hök) Šutara. The results suggest that the source of PTEs for mushrooms is not only the soil but probably also the current wet deposition. The influence of the forest type on the accumulation of PTEs in mushrooms was confirmed mainly due to the strongly divergent behaviour of Zn in beech- vs. spruce-dominated stands. The results point to the need to evaluate mushroom contamination even in the contamination-unburdened forest areas. For future modelling of PTEs pollution in forests, it is necessary to differentiate the tree species composition.

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).

Total mercury and methylmercury (MeHg) in braised and crude Boletus edulis carpophores during various developmental stages

We collected and processed Boletus edulis (King Bolete) carpophores grouped in four batches based on their developmental stage (button stage, young-white, large-white, and large-yellow). The study aimed, for the first time, to examine the B. edulis content and effect of braising and to estimate the intake of total mercury (THg) and methylmercury (MeHg) from a single meal based on whole (wet) weight (ww) and dry weight (dw). In braised carpophores, THg concentrations ranged from 0.2668 ± 0.0090 to 0.5434 ± 0.0071 mg kg-1 ww at different developmental stages, whereas crude products concentrations ranged from 0.1880 ± 0.0247 to 0.2929 ± 0.0030 mg kg-1 ww. The button stage crude carpophores were more highly contaminated with THg than at later stages of maturity, but MeHg levels were lower (p < 0.0001). On the other hand, braised button stage carpophores showed more MeHg than at later maturity stages. MeHg contributed at 1.9 ± 0.7% in THg in crude mushrooms and at 1.4 ± 0.3% in braised meals. The effect of braising was to increase the average THg and MeHg contents in fresh mushroom meals by 52 ± 31% and 53 ± 122% respectively, but a reduction of 40 ±14% and 40 ± 49% respectively was seen on a dw basis. The potential intakes of THg and MeHg from braised meals of B. edulis studied were small and considered safe.

Mercury and selenium in developing and mature fruiting bodies of Amanita muscaria

Both mercury (Hg) and selenium (Se) occur in many mushroom species, but the morphological distribution of these elements during different developmental stages of the fruiting bodies is not known. Although Amanita muscaria can be consumed after suitable processing, they are often ignored by mushroom foragers, leaving an abundance for investigative study. Multiple specimens in each of six developmental stages (button to fully mature) were collected in excellent condition during a single morning from the same forested location and composited. With an average of 30 specimens per composite, and low temporal, spatial, and measurement uncertainty, the data are likely to be representative of the typical concentrations of Hg and Se for each developmental stage. Hg (range 0.58-0.74 mg kg-1 dry weight cap; 0.33 to 0.44 mg kg-1 dw stipe) and Se (range 8.3-11 mg kg-1 dw cap; 2.2 to 4.3 mg kg-1 dw stipe) levels were observed to vary during the developmental stages, and the variability may relate to the demands in growth. In common with some other species, the lower stipe concentrations may be consistent with nutrient/contant transport and support functions. Both Hg and Se levels were lowest during periods of maximum sporocarp growth. Selenium occurs at almost an order of magnitude greater levels than Hg. Due to its role in mitigating the effects of Hg toxicity, this property is of significance to those who consume the species either for nutritional, medicinal, or recreational purposes, although the losses of both these elements during processing are not known.

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.

Assessment of toxicity and environmental behavior of chiral ethiprole and its metabolites using zebrafish model

Ethiprole is effective against a wide range of insects and has been used throughout the world. In this work, the toxicity, bioaccumulation and elimination of ethiprole and its main metabolites (ethiprole sulfone (M1), ethiprole sulfide (M2), ethiprole amide (M3), ethiprole sulfone amide (M4) and desethylsulfinyl ethiprole (M5)) in zebrafish Danio rerio were investigated at enantiomeric level. Rac-ethiprole showed high toxicity (96 h LC₅₀ = 708 μg L^-1) and M2 was six times more toxic than ethiprole (111 μg L^-1). Enantioselective toxicity was observed, with the S-ethiprole (924 μg L^-1) being more toxic than R-ethiprole (2195 μg·L^-1). Rac-ethiprole and M2 could induce oxidative stress in the liver of adult zebrafish and developmental toxicity in zebrafish embryos. Zebrafish were exposed to 100 μg L^-1 rac-/R-/S-ethiprole and the bioaccumulation was monitored during a 21 d period followed by a 7 d metabolism. The bioconcentration factor (BCF) of rac-ethiprole was 17, and the half-lives of rac-ethiprole and metabolites varied between 0.44 and 2.99 d. R-ethiprole was preferentially accumulated and metabolized in zebrafish. Besides, the metabolic pathways of R- and S-ethiprole were found to be different. This study indicated assessment of metabolites and enantioselectivity should be taken into consideration in evaluating environmental risks of ethiprole.

Evaluating mercury concentrations in edible plant and fungi species in the Canadian Arctic environment

Levels of environmental mercury (Hg) within the Canadian Arctic are a current area of concern. Although efforts have been made to reduce Hg released into the environment, levels remain elevated in flora and fauna. This study examined the concentrations of Hg in soil and naturally occurring edible plant and fungi species, identified by local Inuit residents, from eight locations in Iqaluit, Nunavut, and the surrounding area during the summers of 2018 and 2019. Total Hg concentrations were obtained in 24 soil samples, 112 flora samples from 23 plant and five lichen species, and 157 fungal samples from eight species. Median Hg concentrations in plant species ranged from 0.005 μg g^-1 Hg dry weight (dw) in Saxifraga cernua to 0.19 μg g^-1 Hg dw in Oxytropis maydelliana. Median concentrations in edible fungi species ranged from 0.084 μg g^-1 Hg dw in the Cortinarius croceus (non-puffball species) to 1.6 μg g^-1 Hg dw in Lycoperdon perlatum (a puffball mushroom). Additionally, median Hg concentration in puffball species (1.4 μg g^-1 ) were higher than non-puffball species (0.12 μg g^-1 ). Three puffball species were assessed for methylmercury (MeHg), with mean concentrations ranging from 0.013 to 0.085 μg g^-1 MeHg dw. Limited research has been conducted on Hg uptake in naturally occurring edible plant and fungi species of the Canadian Arctic. This study contributes important information on Hg accumulation and processes in edible plant and fungi Arctic species, is the first to focus on plants used by the local Indigenous community, and demonstrates a need for further studies to assess Hg in Arctic environments.

Mercury Content in Three Edible Wild-Growing Mushroom Species from Different Environmentally Loaded Areas in Slovakia: An Ecological and Human Health Risk Assessment

Three edible mushroom species (Imlera badia, Boletus subtomentosus, Xerocomellus chrysenteron) sampled in 60 different localities of Slovakia were evaluated to determine health risks (associated with mercury content) arising from their consumption. Total content of mercury in soil and mushroom samples was determined by an AMA-254 analyzer. Soil pollution by mercury was evaluated by contamination factor (C_f), pollution load index (PLI), and geoaccumulation index (I_geo). Bioaccumulation factor (BAF), translocation factor (Qc/s), provisional tolerably weekly intake (%PTWI), estimated daily intake (EDI), and target hazard quotient (THQ) were used to describe and compare uptake and transition abilities of mushrooms, and the health risk arising from mushroom consumption. Mercury content in soil significantly influences the content of mercury in mushroom fruiting body parts. Caps and stipes of Boletus subtomentosus were found to be the best mercury accumulator. According to the EDI, consumption of the evaluated mushroom species represents a serious threat for adults and children. The lowest values of THQ were found for Xerocomellus chysenteron.

Effects of cadmium stress on physiological indexes and fruiting body nutritions of Agaricus brasiliensis

In this study, 0, 0.5, 1, 1.5, 2, 4, 6 and 8 mg·kg^-1 of cadmium were added to the cultivation materials. In order to study the effects of different concentrations of Cd stress on J1 and J77, the contents of antioxidant enzymes, proline and malondialdehyde, Cd content, agronomic traits and yield of fruiting bodies of Agaricus brasiliensis were determined, and the nutritional components such as polysaccharide, triterpene, protein, total sugar and total amino acid were determined. The results showed that the physiological indexes of strain J1 and J77 changed regularly under different concentrations of Cd stress. J1 was a high absorption and low tolerance variety, while J77 was a low absorption and high tolerance variety. Low concentration of Cd promoted the growth of strain J1, and higher concentration of Cd promoted the growth of strain J77. The contents of protein and total amino acids in the two strains changed greatly, followed by polysaccharides, which indicated that Cd stress had the greatest impact on the three nutrients, and other nutrients were not sensitive to Cd stress.

Direct and Indirect Neurotoxic Potential of Metal/Metalloids in Plants and Fungi Used for Food, Dietary Supplements, and Herbal Medicine

Plants and mushrooms bioconcentrate metals/metalloids from soil and water such that high levels of potentially neurotoxic elements can occur in cultivated and wild species used for food. While the health effects of excessive exposure to metals/metalloids with neurotoxic potential are well established, overt neurological disease from prolonged ingestion of contaminated botanicals has not been recognized. However, the presence of metal elements may affect levels of botanical neurotoxins in certain plants and mushrooms that are established causes of acute and chronic neurological disease.

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.

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.

Mercury in traditionally foraged species of fungi (macromycetes) from the karst area across Yunnan province in China

The objective of this study is to better quantify the occurrence, intake, and potential risk from Hg in fungi traditionally foraged in SW China. The concentrations and intakes of Hg were measured from 42 species including a "hard" flesh type polypore fungi and a" soft" flesh type edible species that are used in traditional herbal medicine, collected during the period 2011-2017. Three profiles of forest topsoil from the Zhenyuan site in 2015 and Changning and Dulong sites in 2016 were also investigated. The concentrations of Hg in composite samples of polypore fungi were usually below 0.1 mg kg-1 dry weight (dw) but higher levels, 0.11 ± 0.01 and 0.24 ± 0.00 mg kg-1 dw, were noted in Ganoderma applanatum and Amauroderma niger respectively, both from the Nujiang site near the town of Lanping in NW Yunnan. Hg concentrations in Boletaceae species were usually well above 1.0 mg kg-1 dw and as high as 10 mg kg-1 dw. The quality of the mushrooms in this study in view of contamination with Hg showed a complex picture. The "worst case" estimations showed probable intake of Hg from 0.006 μg kg-1 body mass (bm) ("hard" type flesh) to 0.25 μg kg-1 bm ("soft" flesh) on a daily basis for capsulated products, from 17 to 83 μg kg-1 bm ("soft" flesh) in a meal ("hard" type flesh mushrooms are not cooked while used in traditional herbal medicine after processing), and from 0.042 to 1.7 and 120 to 580 μg kg-1 bm on a weekly basis, respectively. KEY POINTS: • Polypore species were slightly contaminated with Hg. • Hg maximal content in the polypore was < 0.25 mg kg-1 dry weight. • Many species from Boletaceae family in Yunnan showed elevated Hg. • Locals who often eat Boletus may take Hg at a dose above the daily reference dose.

Interactions between Hg and soil microbes: microbial diversity and mechanisms, with an emphasis on fungal processes

Mercury (Hg) is a highly toxic metal with no known biological function, and it can be highly bioavailable in terrestrial ecosystems. Although fungi are important contributors to a number of soil processes including plant nutrient uptake and decomposition, little is known about the effect of Hg on fungi. Fungi accumulate the largest amount of Hg and are the organisms capable of the highest bioaccumulation of Hg. While referring to detailed mechanisms in bacteria, this mini-review emphasizes the progress made recently on this topic and represents the first step towards a better understanding of the mechanisms underlying Hg tolerance and accumulation in fungal species and hence on the role of fungi within the Hg cycle at Hg-contaminated sites. KEY POINTS: • The fungal communities are more resilient than bacterial communities to Hg exposure. • The exposure to Hg is a threat to microbial soil functions involved in both C and nutrient cycles. • Fungal (hyper)accumulation of Hg may be important for the Hg cycle in terrestrial environments. • Understanding Hg tolerance and accumulation by fungi may lead to new remediation biotechnologies.

Contamination, bioconcentration and distribution of mercury in Tricholoma spp. mushrooms from southern and northern regions of Europe

The contamination, bio-concentration and distribution of mercury (Hg) in wild mushrooms of the genus Tricholoma such as T. equestre, T. portentosum, T. columbeta, and T. terreum were studied, and the possible dietary intake and risk for human consumers in Europe was estimated. Mushrooms, together with the associated forest topsoils were collected from 10 unpolluted and geographically distant areas, far from local or regional emission sources, in Poland (2 sites) and Croatia (8 sites). The Hg contents were in the range 0.10 ± 0.06 to 0.71 ± 0.34 mg kg^-1 dry matter in caps and 0.04 ± 0.02 to 0.38 ± 0.13 mg kg^-1 in stems. The corresponding topsoil concentrations varied over a relatively narrow range between sites, from 0.013 ± 0.003 to 0.028 ± 0.006 mg kg^-1 dry matter. Overall, the study results showed low levels of mercury both, in edible Tricholoma mushrooms and forest topsoils from background (unpolluted) forested areas in Croatia and Poland. The morphological distribution showed considerably greater concentrations of mercury in the caps relative to the stems with ratios ranging from 1.6 ± 0.6 to 3.9 ± 1.8. T. equestre showed good ability to bioconcentrate Hg, with bioconcentration factors (BCF) values in the range 18 ± 7 to 37 ± 18. The data suggests that Tricholoma mushrooms from unpolluted areas in southern and northern regions of Europe can be considered as a low risk food from the point of view of the tolerable Hg intake.

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).

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).

A tale of three cities: Mercury in urban deciduous foliage and soils across land-uses in Poughkeepsie NY, Hartford CT, and Springfield MA USA

Mercury is a global pollutant that harms human and wildlife health through chronic exposure. The role of urban forests in Hg biogeochemistry has been understudied in cities without historical mining or current coal combustion. This study aimed to quantify total Hg concentrations and pools in urban forests to determine whether adjacent land-use impacts Hg accumulation. Three cities in the northeastern United States were studied: Hartford, Connecticut; Poughkeepsie, New York; and Springfield, Massachusetts. We identified ~20 urban forests sites in a ~10 km by ~10 km grid for each city and sampled foliage and soil at each site. Foliage from Populus exhibited significantly lower Hg concentrations (15.6 ± 2.1 ng g^-1) than mean foliar Hg concentrations (23.7 ± 0.6 ng g^-1) but most deciduous genera had comparable concentrations. Average forest floor Hg concentrations (195 ± 21 ng g^-1) and Hg pools (1.9 ± 0.5 mg m^-2) were similar to previous, non-urban studies in the region. Average A horizon (182 ± 19 ng g^-1) and B horizon (125 ± 14 ng g^-1) Hg concentrations were double those of regional forest soils. Mineral soil Hg pools for the top 30 cm (49 ± 6 mg m^-2) averaged two to ten times higher than rural, montane forests in the region. Soil pH, LOI, and %clay were poorly correlated with mineral soil Hg concentrations. Instead, highest foliar and soil Hg concentrations and pools were in urban forests adjacent to high and medium intensity developed areas in Springfield and Hartford. To differentiate the impact of land-uses not captured by the National Land Cover Database (NLCD) system, we implemented new land-use categories. Industrial areas had highest foliar and soil Hg concentrations and pools of any land use. Our results show increasing land-use increases Hg accumulation in urban forests.

Brassica juncea (L.) Czern. (Indian mustard): a putative plant species to facilitate the phytoremediation of mercury contaminated soils

A Phytoremediation experimental set up was established by spiking the soil with varying concentrations of mercury (Hg) (Treatment: T1:10; T2:50; T3:100; T4:500 and T5:1,000 mg Hg/kg soil). Hg removal ability of the Indian mustard plant was determined after 30, 60 and 90 days of exposure. Hg accumulation trend in second and third month of exposure was root > leaf > stem, while for the 1st month it was root > stem > leaf. The highest percentage of Hg accumulation (81%) and glutathione (14 mg/kg) was observed in the plants of T4 and T5 treatment, respectively at 90 days of exposure indicating a high level of Hg stress tolerance. At 90 days of exposure the chlorophyll a content in leaves grown on Hg-free soil (control soil) was 1.8, 2.4, 2.8, 3.6 and 4.4 fold higher than T1, T2, T3, T4 and T5 treatment respectively. With increase in exposure duration, translocation factor decreased whereas bioconcentration factor increased signifying Hg is mainly accumulated in the roots. The study suggests that Brassica juncea can withstand under high Hg contamination and can show great potential to phytostabilize Hg when grown under 100 mg/kg of soil Hg without showing any significant detrimental effect on the plant.

Phytoremediation potential of Miscanthus sinensis for mercury-polluted sites and its impacts on soil microbial community

Phytoremediation potential of Miscanthus sinensis and its impacts on soil microbial community and nutrients were evaluated by pot experiment at soil mercury concentration from 1.48 to 706 mg kg^-1. The changes in biomass yield in dry mass, chlorophyll content, and SOD activity indicated Miscanthus sinensis was tolerant to higher levels of soil mercury exposure, and could grow even if at soil mercury up to 706 mg kg^-1. Mercury bioconcentration and translocation factors were close to or greater than 1 when exposed to soil mercury up to 183 mg kg^-1, demonstrating Miscanthus sinensis a potential phytoremediator for mercury-polluted soils. Miscanthus sinensis planting could significantly improve the diversity and abundance of soil microbial community, but might cause potential loss of soil nitrogen and phosphorus in the early and middle of its growth. In a word, the study indicated Miscanthus sinensis was a promising energy crop linking biofuel production and phytoremediation of mercury-contaminated sites.

Heavy metals in food crops: Health risks, fate, mechanisms, and management

Food security is a high-priority issue for sustainable global development both quantitatively and qualitatively. In recent decades, adverse effects of unexpected contaminants on crop quality have threatened both food security and human health. Heavy metals and metalloids (e.g., Hg, As, Pb, Cd, and Cr) can disturb human metabolomics, contributing to morbidity and even mortality. Therefore, this review focuses on and describes heavy metal contamination in soil-food crop subsystems with respect to human health risks. It also explores the possible geographical pathways of heavy metals in such subsystems. In-depth discussion is further offered on physiological/molecular translocation mechanisms involved in the uptake of metallic contaminants inside food crops. Finally, management strategies are proposed to regain sustainability in soil-food subsystems.

Major and trace elements in Boletus aereus and Clitopilus prunulus growing on volcanic and sedimentary soils of Sicily (Italy)

The aim of this study was to determine and compare the content of 28 elements (Ag, Al, As, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Rb, Sb, Se, Sr, Tl, U, V and Zn) in fruiting bodies of Boletus aereus Bull. and Clitopilus prunulus P. Kumm collected from eleven unpolluted sites of Sicily (Italy) and, also to relate the abundance of chemical elements in soil with their concentration in mushrooms. Median concentrations of the most abundant elements in Boletus aereus ranged from 31,290 μg/g (K) to 107 μg/g (Zn) in caps and from 24,009 μg/g (K) to 57 μg/g (Zn) in stalks with the following abundance order: K > Na > Ca > Mg > Fe > Al > Rb > Zn. The same elements, in the whole fruiting body of Clitopilus prunulus samples, varied in the range 54,073-92 μg/g following the abundance order: K > Na > Mg > Ca > Fe > Al > Rb > Zn. Metal contents in Boletus aereus and in the whole fruiting body of Clitopilus prunulus, collected from the same sampling sites, showed statistically significant differences for most elements. In particular, Clitopilus prunulus contained around two to four times more Co, Cr, Fe, Mg, Mo, Pb, U and V than caps and stalks of Boletus aereus species which, in turn, was from two to four times more enriched in Cu, Se and Tl. Thus, the elemental content of Boletus aereus and Clitopilus prunulus appeared to be species-dependent. The distribution of chemical elements in Boletus aereus was not uniform throughout the whole fruiting body as most elements were significantly bioconcentrated in caps. Furthermore, the fruit bodies of Boletus aereus from the volcanic soil differed both in major and minor elements concentrations from those collected from sedimentary soils. Cadmium and lead concentrations were below the threshold limits for wild mushrooms proposed by EU Directives (2008 and 2015). The elemental content was not significantly influenced by soil pH.

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.

Assessment of nickel bioavailability through chemical extractants and red clover (Trifolium pratense L.) in an amended soil: Related changes in various parameters of red clover

Application of immobilizing agents may efficiently reduce the bioavailability of nickel (Ni) in the soil. Here we report the effect of biochar (BC), gravel sludge (GS) and zeolite (ZE) as a sole treatment and their combinations on the bioavailability of Ni after their application into a Ni-polluted soil. The bioavailability of Ni after the application of immobilizing agents was assessed through an indicator plant (red clover) and chemical indicators of bioavailability like soil water extract (SWE), DTPA and Ca(NO₃)₂ extracts. Additionally, the effects of Ni bioavailability and immobilizing agents on the growth, physiological and biochemical attributes of red clover were also observed. Application of ZE significantly reduced Ni concentrations in all chemical extracts compared to rest of the treatments. Similarly, the combined application of BC and ZE (BC+ ZE) significantly reduced Ni concentrations, reactive oxygen species (ROS) whereas, significant enhancement in the growth, physiological and biochemical attributes along with an improvement in antioxidant defence machinery of red clover plant, compared to rest of the treatments, were observed. Furthermore, BC+ ZE treatment significantly reduced bioconcentration factor (BCF) and bioaccumulation factor (BAF) of Ni in red clover, compared to rest of the treatments. The Ni concentrations in red clover leaves individually reflected a good correlation with Ni concentrations in the extracts (SWE at R²=0.79, DTPA extract at R²=0.84 and Ca(NO₃)₂ extracts at R²=0.86). Our results indicate that combined application of ZE and BC can significantly reduce the Ni bioavailability in the soil while in parallel improve the antioxidant defence mechanism in plants.

Mercury accumulation plant Cyrtomium macrophyllum and its potential for phytoremediation of mercury polluted sites

Cyrtomium macrophyllum naturally grown in 225.73 mg kg^-1 of soil mercury in mining area was found to be a potential mercury accumulator plant with the translocation factor of 2.62 and the high mercury concentration of 36.44 mg kg^-1 accumulated in its aerial parts. Pot experiments indicated that Cyrtomium macrophyllum could even grow in 500 mg kg^-1 of soil mercury with observed inhibition on growth but no obvious toxic effects, and showed excellent mercury accumulation and translocation abilities with both translocation and bioconcentration factors greater than 1 when exposed to 200 mg kg^-1 and lower soil mercury, indicating that it could be considered as a great mercury accumulating species. Furthermore, the leaf tissue of Cyrtomium macrophyllum showed high resistance to mercury stress because of both the increased superoxide dismutase activity and the accumulation of glutathione and proline induced by mercury stress, which favorited mercury translocation from the roots to the aerial parts, revealing the possible reason for Cyrtomium macrophyllum to tolerate high concentration of soil mercury. In sum, due to its excellent mercury accumulation and translocation abilities as well as its high resistance to mercury stress, the use of Cyrtomium macrophyllum should be a promising approach to remediating mercury polluted soils.

Toxicity of Inorganic Mercury to Native Australian Grass Grown in Three Different Soils

In this study, three native Australian grasses namely Iseilema membranaceum (Barcoo), Dichanthium sericeum (Queensland Blue) and Sporobolus africanus (Tussock) were grown in three different soils spiked with different concentrations of inorganic mercury and the root elongation was monitored up to 28 days following the germination. Results showed that mercury at certain concentrations significantly inhibited the root growth of all three tested native grasses grown in three soils, however, the toxicity was less in the soil with high organic carbon content and acidic pH. The calculated EC₅₀ values ranged from 10 to 224 mg/kg total Hg in soil. However, the EC₁₀ values indicated that existing guideline values for mercury may be of protective to the native Australian vegetation. Considering their tolerance to soil mercury, these grass species have the potential for their use in rehabilitation of mercury contaminated sites.

Analysis of some metallic elements and metalloids composition and relationships in parasol mushroom Macrolepiota procera

The aim of the study was to characterise the multi-elemental composition and associations between a group of 32 elements and 16 rare earth elements collected by mycelium from growing substrates and accumulated in fruiting bodies of Macrolepiota procera from 16 sites from the lowland areas of Poland. The elements were quantified by inductively coupled plasma quadrupole mass spectrometry using validated method. The correlation matrix obtained from a possible 48 × 16 data matrix has been used to examine if any association exits between 48 elements in mushrooms foraged from 16 sampling localizations by multivariate approach using principal component (PC) analysis. The model could explain up to 93% variability by eight factors for which an eigenvalue value was ≥1. Absolute values of the correlation coefficient were above 0.72 (significance at p < 0.05) for 43 elements. From a point of view by consumer, the absolute content of Cd, Hg, Pb in caps of M. procera collected from background (unpolluted) areas could be considered elevated while sporadic/occasional ingestion of this mushroom is considered safe. The multivariate functional analysis revealed on associated accumulation of many elements in this mushroom. M. procera seem to possess some features of a bio-indicative species for anthropogenic Pb but also for some geogenic metals.

A Preliminary Investigation on Metal Bioaccumulation by Perenniporia fraxinea

The lignicolous macrofungus Perenniporia fraxinea has drawn increased attention due to its role as a pathogen of ornamentals in urban sites. The present study investigated the bioaccumulation of heavy metals by P. fraxinea. Sporophores were collected from urban and suburban areas in Pavia (Northern Italy) and analyzed for metals content (Cd, Hg, Pb, Ni, Cr, Cu, Fe, Mn, Zn) by inductively coupled plasma mass spectrometer and inductively coupled plasma optical emission spectroscopy, after microwave acidic digestion. On the basis of the obtained results the potential bioaccumulation capability of P. fraxinea was investigated. The isolates were grown in a culture medium enriched with different concentrations of Cd and Hg, chosen as probes of environmental pollution, and Cu for comparison. As P. fraxinea grows in the presence of Cd, Hg and Cu, it seems to be a potential tool in environmental monitoring.

Multi-elemental analysis of Lentinula edodes mushrooms available in trade

The present study investigated the content of 62 elements in the fruiting bodies of Lentinula edodes (Shiitake mushroom) cultivated commercially in Poland on various substrates from 2007-2015. The general mean content (mg kg^-1 dry weight (DW)) of the studied elements ranked in the following order: K (26,335) > P (11,015) > Mg (2,284) > Ca (607) > Na (131) > Zn (112) > Fe (69) > Mn (33) > B (32) > Rb (17) > Cu (14.5) > Al (11.2) > Te (2.9) > As (1.80) > Cd (1.76) > Ag (1.73) > Nd (1.70) > Sr (1.46) > Se (1.41) > U (1.11) > Pt (0.90) > Ce (0.80) > Ba (0.61) > Co (0.59) > Tl (0.58) > Er (0.50) > Pb (0.42) > Li (0.40) > Pr (0.39) > Ir (0.37) > In (0.35) > Mo (0.31) > Cr (0.29) > Ni (0.28) > Sb (0.26) > Re (0.24) > Ti (0.19) > Bi (0.18) > Th (0.12) > La (0.10) = Pd (0.10) > Os (0.09) = Zr (0.09) > Rh (0.08) > Ho (0.07) > Ru (0.06) > Sm (0.04) = Eu (0.04) = Tm (0.04) > Gd (0.03) > Sc (0.02) = Y (0.02) > Lu (0.01) = Yb (0.01) = V (0.01). The contents of Au, Be, Dy, Ga, Ge, Hf, and Tb were below the limits of detection (0.02, 0.02, 0.01, 0.01, 0.01, 0.01, 0.02 mg kg^-1 respectively). The concentrations of Al, As, B, Ba, Ca, Cd, Cr, Er, Fe, In, Lu, Mn, Nd, Sr, Ti, Tm, and Zr were comparable over the period the mushrooms were cultivated. The study revealed that Lentinula edodes contained As and Cd at levels potentially adverse to human health. This highlights the need to monitor these elements in food products obtained from this mushroom species and ensure that only low levels of these elements are present in cultivation substrates.

Bio-augmentation and nutrient amendment decrease concentration of mercury in contaminated soil

Four mercury (Hg) contaminated soils with different pH (7.6, 8.5, 4.2 and 7.02) and total organic carbon contents (2.1, 2.2, 4 and 0.9%) were subjected to bioremediation utilizing a Hg volatilizing bacterial strain Sphingobium SA2 and nutrient amendment. In a field with ~280mg/kgHg, 60% of Hg was removed by bio-augmentation in 7days, and the removal was improved when nutrients were added. Whereas in artificially spiked soils, with ~100mg/kgHg, removal due to bio-augmentation was 33 to 48% in 14days. In the field contaminated soil, nutrient amendment alone without bio-augmentation removed 50% of Hg in 28days. Nutrient amendment also had an impact on Hg remediation in the spiked soils, but the best results were obtained when the strain and nutrients both were applied. The development of longer root lengths from lettuce and cucumber seeds grown in the remediated soils confirmed that the soil quality improved after bioremediation. This study clearly demonstrates the potential of Hg-reducing bacteria in remediation of Hg-contaminated soils. However, it is desirable to trap the volatilized Hg for enhanced bioremediation.

Mercury toxicity to Eisenia fetida in three different soils

Three different soils were spiked with 12 different concentrations of inorganic mercury (Hg). Sub-chronic Hg toxicity tests were carried out with Eisenia fetida in spiked soils by exposing the worms for 28 days following standard procedures. The toxicity studies revealed that Hg exerted less lethal effect on earthworms in acidic soil with higher organic carbon (S-3 soil) where water soluble Hg recovery was very low compared to the water soluble Hg fractions in soils with less organic carbon and higher pH (S-1 and S-2 soils). The concentrations of total Hg that caused 50 % lethality to E. fetida (LC₅₀) after 28 days of exposure in S-1, S-2 and S-3 soils were 152, 294 and 367 mg kg^-1, respectively. The average weight loss of E. fetida in three soils ranged from 5 to 65 %. The worms showed less weight loss in the organic carbon-rich soil (S-3) compared to less organic carbon containing soils (S-1 and S-2). The bioconcentration of Hg in E. fetida increased with increased Hg concentrations. The highest bioaccumulation took place in the acidic soil with higher organic carbon contents with estimated bioaccumulation factors ranging from 2 to 7.7. The findings of this study will be highly useful for deriving a more robust soil ecological guideline value for Hg.