Rare earth elements in parasol mushroom Macrolepiota procera

Levels of Rare Earth Elements in Food and Human Dietary Exposure: A Review

Rare earth elements (REEs) are a group consisting of the following 17 metals: Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Pm, Sc, Sm, Tb, Tm, Y and Yb. In the current century, the number of applications of REEs has significantly increased. They are being used as components in high technology devices of great importance industrial/economic. However, information on the risk of human exposure to REEs, as well as the potential toxic effects of these elements is still limited. In general terms, dietary intake is the main route of exposure to metals for non-occupationally exposed individuals, which should be also expected for REEs. The current paper aimed at reviewing the studies -conducted over the world- that focused on determining the levels of REEs in foods, as well as the dietary intake of these elements. Most studies do not suggest potential health risk for consumers of freshwater and marine species of higher consumption, or derived from the intake of a number of vegetables, fruits, mushrooms, as well as other various foodstuffs (honey, tea, rice, etc.). The current estimated daily intake (EDI) of REEs does not seem to be of concern. However, considering the expected wide use of these elements in the next years, it seems to be clearly recommendable to assess periodically the potential health risk of the dietary exposure to REEs. This is already being done with well-known toxic elements such as As, Cd, Pb and Hg, among other potentially toxic metals.

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

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

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

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

Platinum and Palladium Accumulation in Edible Mushroom Boletus aereus Bull. Growing in Unpolluted Soils of Sicily Region (Italy)

Human exposure to certain metals occurs indirectly through diet. This study was conducted to determine the content of Pt and Pd in fruiting bodies of Boletus aereus Bull. collected from several wooded areas of Sicily with different substrates (sedimentary and volcanic) with limited anthropogenic influence. Determinations were performed by coupled plasma-mass spectrometry (ICP-MS) to quantify Pt and Pd. The concentrations of investigated Pt and Pd in mushroom samples ranged from 0.31 to 3.09 ng g-1 for palladium and 0.21 to 4.22 ng g-1 for platinum. The results of the present study suggest that commonly consumed Boletus aereus mushrooms do not accumulate significant levels of Pt and Pd as demonstrated by bioconcentration factor (BCF) values, and their content is lower than in other food products. Additionally, based on the calculated daily intake rates of Pt and Pd, it can be concluded that occasional consumption of fruiting bodies of B. aereus collected in Sicily is safe. The proposed methodological approach appears to be fully adequate for the reliable quantification of Pt and Pd. The data obtained in this investigation confirm that mushrooms are probative of a significant portion of the total exposure to PGEs due to the diet.

Scandium, yttrium, and lanthanide occurrence in Cantharellus cibarius and C. minor mushrooms

There is a dearth of data on rare earth elements (REE), yttrium and scandium in foods which extends also to baseline datasets for edible wild mushrooms, though this has started to change in the last decade. Concentrations and shale normalized patterns of REE and Y (REY) were studied by using inductively coupled plasma-quadrupole mass spectrometer in 22 pools (2235 specimens) of Cantharellus cibarius (Golden Chanterelle) collected in Poland and also a pool of C. minor (Small Chanterelle) (153 specimens) from Yunnan (Chinese Province). The total REY plus Sc varied in C. cibarius from 10 to 593 µg kg-1 dw whereas that for the Yunnan's C. minor was 2072 µg kg-1 dw. C. minor from Yunnan has higher REY and Sc compared to the C. cibarius. Sc concentrations in twenty C. cibarius pools were below 1 µg kg-1 dw, but 17 and 27 µg kg-1 dw were detected at the other two sites and 66 µg kg-1 dw was detected in C. minor. The median Y content of C. cibarius and C. minor was 22 µg kg-1 dw and 200 µg kg-1 dw. The difference in REY and Sc concentrations and shale normalized patterns between mushrooms from Poland and Yunnan seems to reflect the regional difference in concentration and composition of these elements in the soil bedrock.

Letter to the editor: Comment on "multiannual monitoring (1974-2019) of rare earth elements in wild growing edible mushroom species in Polish forests" by Siwulski et al. https://doi.org/10.1016/j.chemosphere.2020.127173. A recurring question - What are the real concentrations and patterns of REE in mushrooms?

Siwulski et al. (2020) investigated the occurrence of the lanthanides (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu), scandium (Sc) and yttrium (Y) in 4 species of wild mushrooms, which were sampled over a 45 years period in Poland. The reported mean lanthanide concentrations for mushrooms were in the range from 539 to 1601 μg kg^-1 dry weight. These values are considered as highly elevated in the light of data published earlier for the same species, where the analytical results were assessed as not being biased by errors (these could arise from contamination of the samples with soil dust or unsuitable choice of analytical methodology including the use of unsuitable analytical instrumentation for measurement). It has long been established that the lanthanides are naturally distributed in ores, soil bedrock, soils, natural waters and plants in a pattern that reflects the Oddo-Harkins rule. This pattern is correspondingly reflected in fungi, including the same species and have been published earlier by other authors. However, when the individual lanthanide concentration data of B. edulis, I. badia, L. scabrum and M. procera from the study by Siwulski et al. are plotted, they do not display the expected sawtooth (zigzag) concentration pattern - in other words, the concentration data do not follow the Oddo-Harkins rule. Lanthanides are naturally found in very low concentration in foods including wild mushrooms. There is a striking lack of convergence in the results obtained for ICP-MS techniques, and the results obtained from ICP-OES measurement (as used by Siwulski et al.). If the reasons discussed here for anomalies in the reported lanthanides data hold true, how does this affect the data for other elements in mushrooms reported in the commented article?

Comment on "Worldwide basket survey of multielemental composition of white button mushroom Agaricus bisporus": The credibility of the concentration data reported for REE are questioned - are they reliable enough to be included in the database on nutrients in mushrooms?

The focus of this comment is on the Lanthanides (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) which, together with Sc and Y are also called the rare earth elements (REE). Individual REE have similar chemical properties and can be treated as a group. They behave similarly in the environment and in food webs. However, the determination of REE in foods, including edible mushrooms is analytically very challenging. In study by Siwulski et al. (2020) concentrations were reported for Ce, Nd, Sm, La, Sm and Tm, but the others were not detected above the method quantification limit. The sum of Ce (340-2730 μg kg^-1 dw), Nd (10-1220 μg kg^-1 dw), Sm (10-420 μg kg^-1 dw), La (10-130 μg kg^-1 dw), Sm (10-420 μg kg^-1 dw), Tm (10-170 μg kg^-1 dw) in 32 samples of A. bisporus was in the range of 430-3510 μg kg^-1 dry weight. The first visible characteristic is a large difference in the concentrations of Ce, Nd, Sm, La and Tm between the A. bisporus samples and various wild species and cultivated Cyclocybe cylindracea and Pleurotus ostreatus. Secondly, there is no correspondence with the Oddo-Harkins order and the concentrations pattern of Ce, Nd, Sm, La and Tm reported for the A. bisporus samples. The pattern is clearly different from that observed in the wild mushrooms and the two cultivated species reported by other studies. The ICP-OES and also the low resolution ICP-MS determination of REE directly from a fungal digest can suffer from spectral interferences of different types including an effect of the matrix which have to be overcome in the course of reliable and controlled analysis of REE.

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

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

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

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

Speciation and spatial distribution of Eu(III) in fungal mycelium

Europium, as an easy-to-study analog of the trivalent actinides, is of particular importance for studying the behavior of lanthanides and actinides in the environment. Since different soil organisms can influence the migration behavior of these elements, a detailed knowledge of these interaction mechanisms is important. The aim of this study was to investigate the interaction of mycelia of selected wood-inhabiting (S. commune, P. ostreatus, L. tigrinus) and soil-inhabiting fungi (L. naucinus) with Eu(III). In addition to determining the Eu(III) complexes in the sorption solution, the formed Eu(III) fungal species were characterized using scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy, chemical microscopy in combination with the time-resolved laser-induced fluorescence spectroscopy. Our data show that S. commune exhibited significantly higher Eu(III) binding capacity in comparison to the other fungi. Depending on fungal strain, the metal was immobilized on the cell surface, in the cell membranes, and within the membranes of various organelles, or in the cytoplasm in some cases. During the bioassociation process two different Eu(III) fungal species were formed in all investigated fungal strain. The phosphate groups of organic ligands were identified as being important functional groups to bind Eu(III) and thus immobilize the metal in the fungal matrix. The information obtained contributes to a better understanding of the role of fungi in migration, removal or retention mechanisms of rare earth elements and trivalent actinides in the environment.

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

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

Barbero G. 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.

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

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

Estimating the risks from phthalate esters and metal(loid)s in cultivated edible fungi from Jingmen, Central China

Cultivated mushrooms inevitably absorb phthalate esters (PAEs) and potentially toxic metal(loid)s from plastic grow bags and substrate. The associated harm to consumers should be further clarified. This study measured six priority PAEs and nine metal(loid)s in eight mushroom varieties from greenhouses near Jingmen, Hubei, central China. The averaged total target PAE was between 8.60 ± 1.55 and 27.20 ± 5.90 mg kg^-1 dry weight. Levels of di-n-butyl phthalate in all samples and those of di-(2-ethylhexyl) phthalate in four mushroom species exceeded the maximum residual amount of China. Compared with the maximum levels of contaminants for foods in China, Cd in one and Pb in four mushroom species exceeded the limits. The estimated weekly intake of As, Cd, Cu, Hg, and Pb for different age groups was higher than the provisional tolerable weekly intake; however, there was no significant carcinogenic risks based on assessment of single or combined PAEs and metal(loid)s.

No significant transfer of the rare earth element samarium from spiked soil to alfalfa by Funneliformis mosseae

Rare earth elements including samarium have been widely used in modern technologies in recent decades. Following over-exploitation and soil contamination, they can accumulate in plants and be toxic at high concentrations. Arbuscular mycorrhizae benefit plants in metal-contaminated soils by improving their survival and growth and alleviating metal toxicity, but little information is available about soil contaminated by rare earth elements. We performed two experiments using samarium to study the role of arbuscular mycorrhizal fungi on plant growth and samarium transfer to alfalfa in a samarium-spiked soil. A pot experiment was conducted in a soil spiked with two concentrations of samarium and a non-spiked control, inoculated or not with a metal-tolerant Funneliformis mosseae. A compartmented pot experiment was then performed with a separated compartment containing samarium-spiked sand only accessible by F. mosseae fungal hyphae to further study the transport of samarium from the soil to alfalfa. The biomass of alfalfa grown on samarium-spiked soil was reduced, while it was significantly higher following arbuscular mycorrhiza inoculation in the pot experiment, both in the control and samarium-spiked soil. Although mycorrhizal plants had a higher phosphorus content than non-mycorrhizal ones, there was no significant difference in samarium concentrations between mycorrhizal and non-mycorrhizal plants. The compartment experiment confirmed that there was no significant samarium transfer to the plant by F. mosseae. Other fungi and plants should be tested, and field experiments performed, but our results suggest that arbuscular mycorrhizal plants might be considered in phytorestoration of rare-earth-contaminated soils.

Multiannual monitoring (1974-2019) of rare earth elements in wild growing edible mushroom species in Polish forests

There is a growing demand for rare earth elements (REEs) due to their use in modern technologies, and this may result in their emission to the environment. This is the first long-term study to monitor the content of REEs in four edible mushroom species. Over 21,900 samples of fruit bodies (sporocarps) of Boletus edulis, Imleria badia, Leccinum scabrum and Macrolepiota procera and their underlying soils, collected between 1974 and 2019 from 42 forest sites in Poland were examined in an attempt to understand the time evolution of the presence of REEs in the environment. In general, I. badia and B. edulis displayed a greater total content of REEs on mg per kg basis than L. scabrum and M. procera. A gradual increase in REEs in the studied mushrooms as well as associated forest soil samples was observed over the monitored period. Both levels were also highly correlated. Regardless of the considered period, human consumption of these mushrooms would not contribute significantly to dietary exposure to REEs. Wild growing mushroom species studied over a long time period may be a good bioindicator of REE migration to the environment.

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).

Scandium, yttrium, and lanthanide contents in soil from Serbia and their accumulation in the mushroom Macrolepiota procera (Scop.) Singer

The mobility (fractionation) of rare earth elements (REEs) and their possible impacts on ecosystems are still relatively unknown. Soil samples were collected from two sites in central Serbia, an unpolluted mountain region (site 1) and a forest near a city (site 2). In order to investigate REE fractions (acid-soluble/exchangeable, reducible, oxidizable, and residual) in soils, BCR sequential extraction was performed. Additionally, the content of REEs was also determined in stipes and caps of the mushroom Macrolepiota procera, growing in the observed sites. Sc, Y, and lanthanide contents were determined by inductively coupled plasma mass spectrometry (ICP-MS), and results were subjected to multivariate data analysis. Application of pattern recognition technique revealed the existence of two distinguished clusters belonging to different geographical sites and determined by greater levels of Sc, Y, and lanthanides in Goč soil compared to Trstenik soil. Additionally, PCA analysis showed that REEs in soil were concentrated in two groups: the first consisted of elements belonging to light REEs and the second contained heavy REEs. These results suggest that the distribution of REEs in soils could indicate the geographical origin and type of soil. The bioconcentration factors and translocation factors for each REE were also calculated. This study provides baseline data on the rare earth element levels in the wild edible mushroom M. procera, growing in Serbia. In terms of bioconcentration and bioexclusion concept, Sc, Y, and REEs were bioexcluded in M. procera for both studied sites.

Rare earth elements concentration in mushroom cultivation substrates affects the production process and fruit-bodies content of Pleurotus ostreatus and Cyclocybe cylindracea

BACKGROUND

Concentrations of 16 rare earth elements (REEs) and two actinides were determined for the first time both in cultivated mushrooms and in their production substrates by inductively coupled plasma mass spectroscopy. Moreover, the effect of REEs on cultivation parameters and composition of the final product was assessed, together with their potential use for authentication purposes.

RESULTS

The concentrations of REEs varied greatly among seven cultivation substrates and correlated with measurements in Cyclocybe cylindracea mushrooms; no such correlation was established in Pleurotus ostreatus. Reduction of hemicellulose, cellulose, and lignin in substrates during P. ostreatus cultivation was positively correlated with REE concentrations, which also affected the production performance depending on the species examined. In all cases, a negative correlation was established between bioconcentration factors (BCF) in mushrooms and REE content in substrates, while the effect of substrate composition on BCF values varied according to the element studied. The estimated daily intake values of REEs through mushroom consumption was at much lower levels than those reported as potentially harmful for human health.

CONCLUSION

The content of REEs in cultivation substrates and in mushrooms revealed that the bioaccumulation of elements differed in each fungus. The nature/origin of substrates seemed to affect the concentration of REEs in mushrooms to a considerable extent. © 2018 Society of Chemical Industry.

Element distribution in fruiting bodies of Lactarius pubescens with focus on rare earth elements

During growth and senescence, fungal fruiting bodies accumulate essential and non-essential elements to different extent in their compartments. This study bases on a dataset of 32 basidiocarps of the ectomycorrhizal Lactarius pubescens sampled in a former U mining area. Statistical analyses were combined with rare earth element (REE, La-Lu) patterns to study the element distribution within sporocarp compartments and between three different age classes. For this purpose, fruiting bodies were separated into stipe, pileus trama, pileipelles and lamellae, dried and digested with HNO₃. While macronutrient (e.g. K, Mg, P, S) contents resemble those of a non-mining affected site, several elements (e.g. Co, Mn) were site-specifically taken up relative to elevated soil contents. With statistics, two main element distribution groups for L. pubescens were revealed: mainly essential (Cu, Mg, Mn, P, S, Zn, Cd, Co, Ni) and mainly non-essential elements (Al, Ca, Fe, Sr, U, REE). The highest REE contents were found in pileipelles and lamellae, corresponding to relatively small cell sizes. Stipes and pileus trama had low REE contents due to their function as transport systems. During growth, light REE (La-Nd) were strongly enriched in lamellae and pileipelles. Middle REE (Sm-Dy) enrichment was found both in soil and fungal biomass. Contents of nutrients decrease with age, while non-essential elements are enriched especially in pileipelles and lamellae. A weak positive Ce anomaly appeared in the bioavailable soil fraction and in the pileipelles of younger individuals. Substrate dependent uptake thus gets reduced with sporocarp senescence, possibly due to redistribution.

Bio-concentration potential and associations of heavy metals in Amanita muscaria (L.) Lam. from northern regions of Poland

Fruiting bodies of Amanita muscaria and topsoil beneath from six background areas in northern regions of Poland were investigated for the concentration levels of Ag, Al, Ba, Ca, Cd, Co, Cu, Fe, Hg, K, Mg, Mn, Na, Rb, Sr, and Zn. In addition, the bioconcentration factors (BCF values) were studied for each of these metallic elements. Similar to studies from other basidiomycetes, A. muscaria showed species-specific affinities to some elements, resulting in their bioconcentration in mycelium and fruiting bodies. This mushroom growing in soils with different levels of the geogenic metallic elements (Ag, Al, Ba, Ca, Co, Cu, Fe, Hg, K, Mg, Mn, Na, Rb, Sr, and Zn) showed signs of homeostatic accumulation in fruiting bodies of several of these elements, while Cd appeared to be accumulated at a rate dependent of the concentration level in the soil substrate. This species is an efficient bio-concentrator of K, Mg, Cd, Cu, Hg, Rb, and Zn and hence also contributes to the natural cycling of these metallic elements in forest ecosystems.

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.

210Po and 210Pb bioaccumulation and possible related dose assessment in parasol mushroom (Macrolepiota procera)

Presented are results of a study on accumulation and distribution of 210Po and 210Pb in the fruitbodies of parasol mushroom (Macrolepiota procera) and risk to human consumer due to exposure from highly radiotoxic decay particles emitted by both radionuclides. Mushrooms were collected from 16 forested places in central and northern regions of Poland. Activity concentrations of 210Po and 210Pb were determined after radiochemical separation of nuclides and subsequent measurement using validated method and alpha spectrometer. Results showed on spatially heterogeneous distribution of the 210Po and 210Po activity concentrations in M. procera and two interpolation maps were prepared. Activity concentrations of nuclides in dried caps of M. procera were in the range from 3.38 ± 0.41 to 16.70 ± 0.33 Bq∙210Po ∙kg-1 and from 5.11 ± 0.21 to 13.42 ± 0.30 Bq∙210Pb ∙kg-1. Consumption of M. procera foraged in central and northern Poland should not contribute significantly to the annual effective radiation doses from 210Po and 210Pb due to amount of both nuclides accumulated by fungus in caps.

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.