Heavy metal contaminations in edible wild mushroom species from Turkey’s Black Sea region

Blusher mushroom (Amanita rubescens Pers.): A Study of Mercury Content in Substrate and Mushroom Samples from Slovakia with Respect to Locality and Developmental Stages

The edible mushroom Amanita rubescens Pers., regularly collected and consumed in Slovakia, was assessed for health risk due to the mercury content in its fruiting body parts. For this purpose, 364 both from the soil/substrate and mushroom samples from 40 localities in Slovakia were evaluated. At the same time, 21 samples of 7 developmental stages of the fruiting body of A. rubescens were taken in the Žakýlske pleso locality. The total mercury content in the soil and mushroom samples was determined using an AMA-254 analyzer. The contamination factor (Cf) and index of geoaccumulation (Igeo) were used to detect the level of soil pollution by mercury. The ability of A. rubescens to accumulate mercury from the soil environment was evaluated using the bioconcentration factor (BCF), and the distribution of mercury in the mushroom body was evaluated using the translocation quotient (Qc/s). To determine the health risks resulting from mushroom consumption, the percentages of provisional tolerable weekly intake (%PTWI) and target hazard quotient (THQ) were used. The obtained results have confirmed serious content of mercury soil pollution, especially in former mining areas, where the situation is alarming from a health risk point of view. Consumption of A. rubescens was found to be risky, not only in former mining areas, but higher values of mercury were also detected in other parts of Slovakia. Evaluation of the developmental stages of the fruiting body of A. rubescens showed that the highest bioconcentration factor was determined at developmental stage no. VI for caps with a value of 2.47 mg kg-1 and developmental stage VII for stipes with a value of 1.65 mg kg-1 DW.

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

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

Investigating the pollution of irrigated plants (Rosmarinus officinalis) with polluted water in different growth stages using spectrometer and K-means method

Rosmarinus officinalis is a widely cultivated plant with various medicinal and culinary uses. However, irrigation with contaminated water can lead to the accumulation of heavy elements in the tissues of this plant. Therefore, the purpose of this study was to investigate the contamination of Rosmarinus officinalis with heavy elements during irrigation with polluted water (wastewater). To achieve this, 39 seedlings were uniformly planted in pots and irrigated with water contaminated with zinc, lead, nickel, and cadmium. The level of contamination in the plant was measured at three vegetative stages using target hazard quotient (THQ), hazard index (HI), and bioconcentration factor (BCF) indicators. In addition, a spectrometer in the range of 400-1030 nm was used to measure the amount of reflection of plants to electromagnetic waves. The K-means method was then applied to investigate the relationship between the morphological characteristics of the plants and heavy metal pollution. The results showed that the highest THQ values were observed in the third vegetative stage (THQPb = 113, THQNi = 0.08, THQZn = 0.25, THQCd = 0.1). Furthermore, the BCFCd and BCFPb indices indicated that the highest contamination levels occurred in the third vegetative stage. The regression analysis identified the spectral bands of 880, 580, 1030, 400, 760, 570, 650, 1050, 560, and 910 nm as the most important for identifying heavy element-contaminated plants. Finally, the K-means method showed high accuracy (R2 = 0.89) for identifying and classifying plant organs affected by pollution from healthy parts. It is worth noting that the investigation of the contamination of Rosmarinus officinalis with heavy elements using electromagnetic waves represents a novel contribution to the field, particularly given the importance of this plant in the pharmaceutical and food industries.

Pleurotus pulmonarius Strain: Arsenic(III)/Cadmium(II) Accumulation, Tolerance, and Simulation Application in Environmental Remediation

The arsenic (As, III) and cadmium (Cd, II) accumulation and tolerance traits of a new strain Pleurotus pulmonarius MT were evaluated, and the utilization of the strain for repairing contaminated liquid and soil was explored. The hypha cultivated in potato dextrose agar (PDA) exhibited medium or high Cd accumulation (0 to 320 mg/L), medium Cd tolerance (maximum tolerated concentration, MTC ≥ 640 mg/L), medium As accumulation (0 to 80 mg/L), and high As tolerance (MTC > 1280 mg/L). The hypha has application potential in processes related to the removal of Cd and As in aqueous pollutants at concentrations of 80 mg/L Cd and 20 mg/L As. The trends obtained for the fruiting bodies of P. pulmonarius MT seemed to deviate from those of the hypha of this strain. The results show that the fruiting bodies featured medium As accumulation (0 to 40 mg/kg), medium As tolerance (MTC > 160 mg/kg), medium Cd accumulation (0 to 10 mg/kg), and high Cd tolerance (MTC > 1280 mg/kg). The fruiting bodies of P. pulmonarius MT were utilized in processes related to the recovery of Cd and As in substrates, that is, 12% contaminated soil mixed with 50 mg/kg Cd and 200 mg/kg As; thus, the hypha and fruiting bodies of P. pulmonarius MT can be used for the decontamination of water and soil containing As(III) and Cd(II).

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.

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.

Edible Mushrooms for Sustainable and Healthy Human Food: Nutritional and Medicinal Attributes

Global food production faces many challenges, including climate change, a water crisis, land degradation, and desertification. These challenges require research into non-traditional sources of human foods. Edible mushrooms are considered an important next-generation healthy food source. Edible mushrooms are rich in proteins, dietary fiber, vitamins, minerals, and other bioactive components (alkaloids, lactones, polysaccharides, polyphenolic compounds, sesquiterpenes, sterols, and terpenoids). Several bioactive ingredients can be extracted from edible mushrooms and incorporated into health-promoting supplements. It has been suggested that several human diseases can be treated with extracts from edible mushrooms, as these extracts have biological effects including anticancer, antidiabetic, antiviral, antioxidant, hepatoprotective, immune-potentiating, and hypo-cholesterolemic influences. The current study focuses on sustainable approaches for handling edible mushrooms and their secondary metabolites, including biofortification. Comparisons between edible and poisonous mushrooms, as well as the common species of edible mushrooms and their different bioactive ingredients, are crucial. Nutritional values and the health benefits of edible mushrooms, as well as different biomedical applications, have been also emphasized. Further research is needed to explore the economic sustainability of different medicinal mushroom bioactive compound extracts and their potential applications against emerging diseases such as COVID-19. New approaches such as nano-biofortification are also needed to supply edible mushrooms with essential nutrients and/or to increase their bioactive ingredients.

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

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

Toxicity, mutagenicity and trace metal constituent of Termitomyces schimperi (Pat.) R. Heim (Lyophyllaceae) and kaolin, a recipe used traditionally in cancer management in Cote d'Ivoire

ETHNOPHARMACOLOGICAL RELEVANCE

Some local communities in Cote d'Ivoire use the mushroom Termitomyces schimperi combined with kaolin (TSK) to manage various cancers in patients. However, there is a paucity of data on toxicity, mutagenicity and trace metal constituent of TSK.

AIM OF THE STUDY

We sought to investigate the acute and sub-chronic toxicities, mutagenic potential, and trace metal constituents of TSK.

MATERIALS AND METHODS

To assess acute toxicity, single doses (1000, 3000 and 5000 mg/kg) of aqueous extract of TSK were administrated per os to Sprague Dawley (SD) rats on Day 1. The rats were then monitored for 13 consecutive days. Sub-chronic toxicity was evaluated by daily administration of 200 and 500 mg/kg of the extract per os for 90 consecutive days. SD rats used as control received distilled water. Signs of toxicity, changes in body weight and mortality were monitored. After the aforementioned monitoring processes, rats were sacrificed and blood collected for full blood count and biochemistry analysis. Animal organs were also collected for histopathological examination. The mutagenic potential of the aqueous extract of TSK (10000 μg/mL) on TA98 Salmonella typhimurium was estimated. Additionally, energy-dispersive X-ray fluorescence (ED-XRF) method was employed to determine trace metal constituents of TSK.

RESULTS

Single-dose administration of 5000 mg/kg of TSK did not cause any death in the SD rats; thus, LD50 was above 5000 mg/kg. Administration of 1000 and 3000 mg/kg of the aqueous extract of TSK did not cause any significant change in behaviour and body weight of SD rats during the 14-day monitoring period. However, the mean corpuscular volume and the mean corpuscular haemoglobin concentration increased significantly (p < 0.01) among rats administered 1000 and 3000 mg/kg of TSK. There was a significant increase (p < 0.0001) in alanine transaminase levels in rats administered 1000 and 3000 mg/kg of TSK extract compared with control. Conversely, there was a significant decrease (p=0.0122) in serum creatine level among rats administered 1000 and 3000 mg/kg of TSK extract compared with control. After 14 days, there were minimal changes with isolated organs of TSK-treated and control rats. Furthermore, 90-day treatment with extract of TSK caused no significant change in parameters assessed. TSK induced frameshift gene mutation in S. typhimurium before (p < 0.05) and after metabolic activation (p < 0.001). Elemental analysis of TSK revealed the presence of toxic (aluminium) or potentially toxic (silver, rabidium, titanium and zirconium) elements.

CONCLUSIONS

The aqueous extract of TSK showed no toxicity (acute and sub-chronic) at doses tested. These findings are consistent with the absence of heavy metals (i.e., cadmium) and potentially toxic elements (i.e., uranium) in TSK samples analysed. TSK showed some level of mutagenic potential. Further mutagenic and chronic toxicity studies on TSK are required.

The Concentration and Probabilistic Health Risk of Potentially Toxic Elements (PTEs) in Edible Mushrooms (Wild and Cultivated) Samples Collected from Different Cities of Iran

The present study was devoted to investigate the PTE concentrations including cadmium (Cd), chromium (Cr), copper(Cu), iron (Fe), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), arsenic(As), and zinc (Zn) among six types of edible wild, 23 cultivated mushroom samples collected from Iran's market by the aid of an inductively coupled plasma-optical emission spectrometry (ICP-OES). Also, the related health risk assessment was established by the aid of the Monte Carlo simulation method (MSC). The limit of detection (LOD) and limit of quantification (LOQ) were ranged 0.001-0.048 and 0.003-0.160 ppm, respectively. The concentrations of As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn were determined in the ranges of 0.003-11. 5, 0.0008-5.89, 0.32-26.32, 9.15-110.08, 15.25-751.17, 0.16-2.24, 2.1-60.47, 1.21-24.22, 0.16-8.92, and 37.13-268.11 mg kg^-1, respectively. According to findings, highest mean concentration of Cr in both types of mushrooms (cultivated and wild) was lower than recommended level by Codex Alimentarius/Food and Agriculture Organization/World Health Organization (CODEX/FAO/WHO) while the corresponding values for Hg (0.87 mg kg^-1), As (1.39 mg kg^-1), Ni (10.08 mg kg^-1), Cu (36.65 mg kg^-1), Cr (10.44 mg kg^-1), Cd (0.589 mg kg^-1), Fe (201.04 mg kg^-1), Mn (10.30 mg kg^-1), Zn (2266.43 mg kg^-1), and Pb (3.81 mg kg^-1) were higher than related standard levels. According to the health risk assessment, no concern regarding the non-carcinogenic risk due to the ingestion of PTEs via the consumption of the edible mushrooms, except Hg in wild mushrooms for children, was noted.

Effect of multi-walled carbon nanotubes on extractability of Sb and Cd in contaminated soil

The interaction between multi-walled carbon nanotubes (MWCNTs) and soil heavy metals was rarely studied. With the convenience of detecting multiple metal elements by ICP-AES, this paper examined the potential effectiveness of MWCNTs on extractability of antimony (Sb) and cadmium (Cd) in contaminated soil. Three-step sequential extraction procedure, toxicity characteristic leaching procedure, bioaccessibility and CaCl₂ single extraction were employed to evaluate Sb and Cd speciations and their extractabilities. According to our results, only at low Sb content level of 100 mg/kg, antimony bioavailability reduced with MWCNTs addition of 0.3% and 0.9% by 22.97% and 20.74%, respectively, which might due to the increase of adsorption point, nevertheless, the excess Sb(OH)₆^- was not adsorbed more efficiently. Secondly, due to the difference in effective specific surface area, only under the condition of high content level and MWCNTs addition of 0.1%, the mild acid-soluble fraction increased at most by 15.40% for Sb and 9.40% for Cd, respectively. However, in terms of TCLP-extractable Sb and Cd and CaCl₂-extractable Sb and Cd, no significant, continuous, regular extractability pattern were found. Overall, MWCNTs were selective on extractability of soil heavy metals due to mechanisms of physical adsorption. This paper provides data reference for the interaction between MWCNTs and soil heavy metals extractability.

Risk Assessment of Potential Food Chain Threats from Edible Wild Mushrooms Collected in Forest Ecosystems with Heavy Metal Pollution in Upper Silesia, Poland

In this study, the contents of selected heavy metals (Zn, Cu, Cd, Pb, Cr, and Ni) and macroelements (C, N, K, P, S, Mg, Na, and Ca) were measured in wild mushrooms growing in a heavily polluted forest ecosystem in the northeastern part of the Upper Silesian Industrial Region. The research was conducted on 10 species of mushrooms belonging to three families: Boletaceae, Russulaceae, and Suillaceae. Using a spatial autoregressive model, the study showed a strong relationship between heavy metal concentrations (especially Zn, Pb, and Cd) and the distance from a source of industrial pollution (a zinc smelter, Huta Miasteczko Śląskie). The concentrations of potentially toxic metals (Pb and Cd) in mushrooms significantly exceeded food-acceptable standards. The bioconcentration factor (BCF), calculated as the ratio between the concentration in mushroom tissues and in forest soils overall, reached the highest values for cadmium (Cd). The highest accumulation capacity for Cd was noted for Imleria badia (BCF = 9.18), which was also the most abundant mushroom species in the study plots. In general, the established threshold values for Pb and Cd concentrations in consumer mushrooms and food products were exceeded up to almost 30-fold in the studied area. We conclude that the potential risk to human health of the toxic elements that enter the food chain through the harvesting and consumption of wild mushrooms from this region is significant.

Assessment of heavy metals contamination and the risk of non-cancerous diseases in vegetable using electromagnetic-chemical

This study seeks to assess the reaction of the eggplant (Solanum melongena L.) to soil samples contaminated. Following, cultivation, growth, and harvest, the plant samples were prepared and maximum absorption rates of heavy metals were measured in both leaf and fruit. The estimated daily intake (EDI), the target hazard quotient (THQ), and the bio-concentration factor (BCF) were measured at various intervals during the growth period of the plant. Spectral analysis was also performed to assess the reaction of target crops to heavy metals. The results showed that in the second and third stages of plant growth, the THQ values were more than 1 for infected plants with Cd, Pb, and Zn. According to results from the BCF analysis, the absorption rate in Pb, during the growth stages was relatively high, in crops contaminated by Ni was around 1 in the second and third stages, and in plants contaminated by Cd was extremely high. All crops contaminated by heavy metals showed higher reflection rates in the 400-500 and 600-700 nm range. So, using electromagnetic waves during different stages of growth, the reaction of eggplant cultivated in soil samples contaminated by heavy metals is predictable.

Probabilistic carcinogenic and non-carcinogenic risk assessment of heavy metal ingestion through consumption of different walnut cultivars: An Iranian study

The heavy metal levels in six walnut cultivars from five geographical zones of Iran were measured. An assessment of risks was conducted by calculating the Target Hazard Quotient (THQ) and Incremental Lifetime Cancer Risk (ILCR) by use of the Monte Carlo simulation method. The highest amounts of As and Pb were reported in Farouj samples. Also, the highest levels of Cr, Zn, Cu and Mn were determined in samples collected from Tuyserkan. Accordingly, 50th and 95th ILCRs for general population due to consumption of walnut were 1.03 × 10^-4 and 3.11 × 10^-4 (for As), 4.10 × 10^-6 and 1.1 × 10^-5 (for Cr) and 4.71 × 10^-9 and 1.05 × 10^-8 (for Pb), respectively. In addition, the 50th and 95th centiles of the HIs for walnut ingestion by Iranians were 1.02 and 2.05, respectively, indicating a minor chance of non-cancer effects. Based on the calculated 95% ILCR, dietary exposure to As through the consumption of walnut poses a risk to Iranian consumer health. However, ILCR values of other heavy metals (HMs) were in acceptable ranges (ILCR < 1 × 10^-4), representing no toxicological concern for consumers. The most significantly influential parameters were determined by sensitivity analysis during the MCS. According to THQ and ILCR methods, concentration was the most sensitive parameters. For THQ method the concentration effects were ranged from 72.4 to 85.1%. Moreover, for ILCR method the effects of concentration in As, Cr, and Pb were 87.1, 79.1 and 83.54%, respectively.

Assessment of potential human health risk of trace element in wild edible mushroom species collected from Yunnan Province, China

Wild edible mushrooms are rich in nutritions and popular among people, but wild edible mushrooms easily accumulate potentially harmful trace elements, and excessive intake will harm health. The aim of this study was to investigate the potential health hazards of long-term intake of wild edible mushrooms in Yunnan Province, China. The concentrations of trace element (As, Cd, Cr, Cu, Hg, Pb, Ni, and Zn) in 19 species of wild edible mushrooms in Yunnan Province were determined by inductively coupled plasma mass spectrometry (ICP-MS). Further processing of the data, the potential health risk assessments of consumers were evaluated by the target hazard quotient (THQ), hazard index (HI), and incremental lifetime cancer risk (ILCR), respectively. Results showed that concentrations of trace element in wild edible mushrooms decreased in the order of Zn > Cu > As > Ni > Cr > Cd > Pb > Hg. Compared with the maximum standard by the WHO/China, the averages of As, Cd, Cr, Hg, and Zn were significantly greater than the standard. Among the tested wild edible mushrooms, HI values of Leccinum crocipodium, Thelephora ganbajun, Lactarius luteolus, Tricholoma matsutake, and Polyporus ellisii were more than 1. Thus, Leccinum crocipodium, Thelephora ganbajun, Lactarius luteolus, Tricholoma matsutake, and Polyporus ellisii are the main sources of risk. The value of THQ in ascending order was as follows: Pb (0.11) < Cd (0.75) < As (4.27) < Hg (6.87). Thus, Hg are the primary sources of health risk in the wild edible mushrooms in Yunnan Province. ILCR_(As) values of Thelephora ganbajun, Tricholoma matsutake, Laccaria amethystea, and Polyporus ellisii were more than 10^-4, these four samples are the primary sources of health risk. The mean values of ILCR for As in wild mushroom were 1.01 × 10^-4. The results suggest that there was potential health risk to the consumer associated with the long-term consumption of wild edible mushrooms collected from Yunnan Province. We propose that the concentrations of trace element should be periodically monitored in wild edible mushrooms.

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).

Cobalt speciation and phytoavailability in fluvo-aquic soil under treatments of spent mushroom substrate from Pleurotus ostreatus

Cobalt (Co) is a nutrient for soil microorganisms and crops, as well as a worldwide industrial pollutant. When the level of Co exceeds the acceptable limit, this heavy metal can lead to devastating consequences for soil environments. There is considerable attention and concern about elevated levels of Co contaminating soil and crops. Spent mushroom substrate (SMS) is a potential amendment for the adsorption of pollutants, which has potential for resolving Co-polluted soil that spans the world. To investigate the environmental behavior and risks associated with Co in fluvo-aquic soil under specific treatments of SMS from Pleurotus ostreatus, a lab-scale pot experiment was conducted. SMS and exogenous Co were added to soil, which was retained for approximately 30 days. Pakchois (Brassica chinensis L.) were planted in the treated soil for 28 days until harvest. The Co speciation in soil (modified BCR sequential extraction) and Co accumulation in pakchoi tissue were studied. When the SMS concentration was within a range of 0 to 9 g kg^-1 (total amount = 0 to 2.7 g), Co in the acid-soluble fraction was transformed to the oxidizable fraction in soil, resulting from the mesh structure on the surface of SMS, as well as the amide and carboxyl in the SMS molecular structure. In this situation, the Co accumulation levels in the pakchois decreased significantly (P < 0.05), indicating the efficacy of SMS for reducing Co phytoavailability. However, when the SMS concentration reached 12 g kg^-1, the phytoavailability increased again (P < 0.05). When the SMS concentration ranged from 8.86 to 9.51 g kg^-1, the Co phytoavailability in soil reached a minimum, while the biomass of pakchoi reached a maximum. Conclusively, SMS from Pleurotus ostreatus are effective for reducing the Co phytoavailability, as well as for reducing the chance of Co transferring into a human's body through crops (i.e., food consumption). In order to achieve the optimum efficacy, the SMS concentration in soil should be maintained at a range of 8.86 to 9.51 g kg^-1.

Effects of corn stalk cultivation substrate on the growth of the slippery mushroom (Pholiota microspora)

Corn stalks are a major source of agricultural waste in China that have the potential for more efficient utilisation. In this study, we designed substrate formulas with different proportions of corn stalks to cultivate Pholiota microspora. The substrate formula for P. microspora cultivation that could partially or completely replace sawdust with corn stalks was selected through the analysis of mycelial growth rates, fruiting body traits, yield, biological efficiency, nutrients, and mineral composition. Our results showed that the substrate formula T2 (38% wood chips and 38% corn stalks) resulted in the highest yield of 275.66 ± 2.87 g per bag, which was 6.60% higher than that of formula CK, and the highest biological efficiency of 90.75 ± 0.04%, which was 4.58% higher than that of CK, with no significant differences from CK in terms of fruiting body traits, nutrients, or mineral composition. The substrate formula T1 (19% corn stalks) led to mushroom yields with the highest mineral and amino acid contents and was thus more suitable for the cultivation of medicinal P. microspora. Therefore, substrates comprising a mixture of corn stalks and sawdust can be used as a novel, inexpensive, and high-yield alternative for the cultivation of P. microspora.

Functionalizing bottom ash from biomass power plant for removing methylene blue from aqueous solution

In order to seek a possible path for utilization bottom ash, the solid waste from biomass incineration for power generation, its basic characteristics were investigated, and removing methylene blue (MB) from aqueous solution was attempted as well. Results indicated bottom ash dominantly contained Si and Ca-related minerals with >35 mineral elements, meanwhile, it was typically characterized by alkalinity (pH of 9.5) and low specific surface area (14.5m²/g). As the only bottom ash was employed for removing MB, removal efficiency was lower than 44%, however, it was greatly improved to 100% as hydrogen peroxide was supplemented (final concentration of 4.0%). Based on the elucidated mechanisms, Fenton-like reaction was triggered by bottom ash, which was dominantly responsible for removing MB, rather than the adsorption by bottom ash. Besides, increasing reaction temperature and duration dramatically promoted MB removal by bottom ash with the aid of hydrogen peroxide (HBA). A great promotion on MB removal from 92.3mg/g to 143.9mg/g was achieved as pH was adjusted from 2.0 to 5.0, indicating MB removal was pH-dependent. The maximum removal of 260.9mg/g was achieved by HBA at a relatively high initial MB concentration of 2000.0mg/L, suggesting a great potential in treating dye wastewater by functionalizing bottom ash with the aid of hydrogen peroxide. Moreover, the released heavy metals and derived by-products from MB removal were acceptable in consideration of their potential environmental risks. Thus, the current work offers a new path to valorize the solid waste in biomass electricity generation plant.