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Phosphorus and molybdenum play important roles in the formation of microbial cell structures and specific enzymes crucial for metabolic processes. Nevertheless, questions remain about the preservation of these elements within ancient microfossils. Here, we present shape-accurate ion images capturing phosphorus and molybdenum on Palaeoproterozoic filamentous microfossils by pioneering a methodology using lateral high-resolution secondary ion mass spectrometry. Introducing electrically conductive glass for mounting isolated microfossils facilitated clearer observations with increased secondary ion yields. Phosphorus was detected along the contours of microfossils, providing direct evidence of phospholipid utilization in the cell membrane. Trace amounts of molybdenum were detected within microfossil bodies, suggesting potential remnants of molybdenum-bearing proteins, such as nitrogenase. These findings align with the hypothesized cyanobacterial origin of filamentous gunflint microfossils. Our methodology introduces a groundbreaking tool for obtaining crucial insights into the cellular evolution and metabolic pathways of microorganisms, allowing comparisons of their morphological characteristics., (© 2024. The Author(s).)

This study focused on a molybdenum mining area in the Qinling Mountains （Shaanxi segment）. Crop and corresponding soil samples were collected from the vicinity of the mining area, and the concentrations of six heavy metals （Cr, Cu, Zn, As, Cd, and Pb） were determined. Soil heavy metal pollution was assessed using single-factor, comprehensive pollution, and geo-accumulation index methods. The primary sources of soil heavy metals were analyzed using the PMF model. A health risk assessment for soil and crops was conducted using the USEPA model. The results revealed severe pollution of agricultural soils by Cr, Cu, Zn, Cd, and Pb. Among these, Cr may have been primarily sourced from chrombismite nearby mining activities, contributing to 85.1% of the pollution. Cu and As were mainly sourced from agriculture, contributing 50.3% and 70.6%, respectively. Zn and Cd were primarily sourced from natural sources such as metal slag dust and rainwash from the mining area, contributing 73.5% and 48.7%, respectively. Pb was primarily sourced from transportation sources, contributing to 54.7% of the pollution. Crop metal contamination was especially severe for Cr, followed by Pb, whereas As and Cd contamination was relatively lower. Crops were significantly impacted by heavy metal pollution in agricultural soils. The health risk assessment indicated non-carcinogenic and carcinogenic risks for children due to soil heavy metals, whereas adults faced acceptable levels of risk. Both adults and children were exposed to highly significant non-carcinogenic and carcinogenic risks from heavy metals in the crops. Moreover, it is essential to implement effective measures to control heavy metal pollution from tailings to safeguard nearby residents, especially children, from adverse health risks.

Herein, we reported the dual functions of molybdenum disulfide/sulfur-doped graphitic carbon nitride (MoS 2 /SGCN) composite as a sensing material for electrochemical detection of 4-NP and a catalyst for 4-NP degradation. The MoS 2 nanosheet, sulfur-doped graphitic carbon nitride (SGCN) and MoS 2 /SGCN were characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) spectroscopy and X-ray photoelectron spectroscopy (XPS). Electrochemical characterization of these materials with electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) in 1 mM K 4 [Fe(CN) 6 ] 3-/4- show that the composite has the lowest charge transfer resistance and the best electrocatalytic activity. The limit of detection (LOD) and the linear range of 4-nitrophenol at MoS 2 /SGCN modified glassy carbon electrode (MoS 2 /SGCN/GCE) were computed as 12.8 nM and 0.1 - 2.6 μM, respectively. Also, the percentage recoveries of 4-NP in spiked tap water samples ranged from 97.8 - 99.1 %. The electroanalysis of 4-NP in the presence of notable interferons shows that the proposed electrochemical sensor features outstanding selectivity toward 4-NP. Additionally, the results of the catalytic degradation of 4-NP at MoS 2 /SGCN show that the nanocatalyst catalyzed the transformation of 4-NP to 4-aminophenol (4-AP) with a first-order rate constant (k) estimated to be 4.2 ×10 -2 s -1 . The results of this study confirm that the MoS 2 /SGCN nanocatalyst is a useful implement for electroanalytical monitoring and catalytic degradation of the hazardous 4-NP in water samples., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The Chinese yam ( Dioscorea polystachya , DP) is promising for the food and pharmaceutical industries due to its nutritional value and pharmaceutical potential. Its proper cultivation is therefore of interest. An insufficient supply of minerals necessary for plant growth can be manifested by discoloration of the leaves. In our earlier study, magnesium deficiency was excluded as a cause. As a follow-up, this work focused on manganese and molybdenum. To quantify both minerals in leaf extracts of DP, analytical methods based on atomic absorption spectrometry (AAS) using the graphite furnace sub-technique were devised. The development revealed that the quantification of manganese works best without using any of the investigated modifiers. The optimized pyrolysis and atomization temperatures were 1300 °C and 1800 °C, respectively. For the analysis of molybdenum, calcium proved to be advantageous as a modifier. The optimum temperatures were 1900 °C and 2800 °C, respectively. Both methods showed satisfactory linearity for analysis. Thus, they were applied to quantify extracts from normal and discolored leaves of DP concerning the two minerals. It was found that discolored leaves had higher manganese levels and a lower molybdenum content. With these results, a potential explanation for the discoloration could be found.

Placental health and foetal development are dependent upon element homeostasis. Analytical techniques such as mass spectroscopy can provide quantitative data on element concentrations in placental tissue but do not show spatial distribution or co-localisation of elements that may affect placental function. The present study used synchrotron-based X-ray fluorescence microscopy to elucidate element content and distribution in healthy and pathological placental tissue. The X-ray fluorescence microscopy (XFM) beamline at the Australian Synchrotron was used to image trace metal content of 19 placental sections from healthy term ( n = 5, 37-39 weeks), foetal growth-restricted ( n = 3, <32 weeks, birth weight <3rd centile), postdate ( n = 7, >41 completed weeks), and stillbirth-complicated pregnancies ( n = 4, 37-40 weeks). Samples were cryo-sectioned and freeze-dried. The concentration and distribution of fourteen elements were detected in all samples: arsenic, bromine, calcium, chlorine, copper, iron, molybdenum, phosphorous, potassium, rubidium, selenium, strontium, sulphur, and zinc. The elements zinc, calcium, phosphorous, and strontium were significantly increased in stillbirth placental tissue in comparison to healthy-term controls. Strontium, zinc, and calcium were found to co-localise in stillbirth tissue samples, and calcium and strontium concentrations were correlated in all placental groups. Molybdenum was significantly decreased in stillbirth, foetal growth-restricted, and postdate placental tissue in comparison to healthy-term samples ( p < 0.0001). Synchrotron-based XFM reveals elemental distribution within biological samples such as the placenta, allowing for the co-localisation of metal deposits that may have a pathological role. Our pilot study further indicates low concentrations of placental molybdenum in pregnancies complicated by foetal growth restriction, postdate delivery, and stillbirth.

The water and sediment samples were collected from the Yu River and Taowanbei River during periods of summer and winter. The NCPI, EWQI, I geo and PERI were used to evaluate the pollution degree and cumulative ecological risk of HMs in the water and sediments. The PMF model was used to analyze the sources of HMs in river sediments. The pollution degree of Cd, Hg and Zn in the water reached the severe pollution level, in the rank of Hg > Zn > Cd. Cd and Zn in sediments are heavily polluted, Cu is lightly polluted, Pb and As are within the warning range, and the pollution rank is Cd > Zn > Cu > Pb > As. The cumulative ecological risk of HMs in sediments reached extremely strong level, mainly Cd and Hg. The main sources of HMs in sediments are mining sources, mixed agricultural and transport sources, and natural sources, which contributed 42.1 %, 34.1 % and 23.8 %, respectively., Competing Interests: Declaration of competing interest The authors declare no competing interest and relevant relationships with other people or organizations that can inappropriately influence our research work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Statement of Problem: The leaching of elements from long-term definitive prostheses, with saliva acting as an electrolyte, poses a biological concern. The approximate concentration in the biological samples that are considered clinically toxic ranges from 1 to 5000 nmol/L for Cr and Co, 1 to 200 nmol/L for Ni, and 1 to 20 nmol/L for Mo. While in vitro studies are available regarding the leaching of elements in artificial saliva, solutions containing protein, solutions of different pH, and different culture media, the in vivo effects of leaching in the biological sample with increasing time are unknown., Purpose: The purpose of this clinical study was to quantify the Ni, Co, Cr, and Mo metals in saliva and blood before and after restoration with prostheses made from 3 different brands of dental casting alloy at 6 and 12 months., Material and Methods: Three popular brands of Ni-Cr alloy with different compositions were evaluated. A total of 150 participants requiring a definitive prosthesis were enrolled and divided into 3 groups (n=50). Heavy metal levels from saliva and blood were measured by using the inductively coupled plasma mass spectroscopy method before cementation of the prosthesis and after 6 and 12 months., Results: The presence of Ni in saliva was in the range of 10.34 to 12.12 μg/L, Cr was 1.04 to 1.22 μg/L, and Mo was 1.04 to 1.08 μg/L over a period of 6 and 12 months after cementation of the metal prosthesis. The presence of Ni in blood was in the range of 6.35 to 14.45 μg/L and that of Cr was 9.09 to 16.16 μg/L over a period of 6 and 12 months after cementation. Co levels were not detected from any brands in saliva or blood, and Mo was detected only in the saliva samples., Conclusions: Increased levels of Ni and Cr in saliva and blood from all 3 brands of base metal alloy at 6 and 12 months were observed at higher than threshold values., (Copyright © 2022 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Shaanxi Province is located in the most important molybdenum ore district in the world, but a lot of molybdenum tailings have been released, polluting the environment and wasting resources seriously. Taking eleven tailing samples collected at the main molybdenum tailings ponds in Shaanxi Province as the research object, the physical, chemical, and mineralogical characteristics were studied through scanning electron microscope, X-ray fluorescence, X-ray diffraction, inductively coupled plasma mass spectrometer, and others. The ecological risk and utilization potential of molybdenum tailings were investigated through leaching test, geo-accumulation index, potential ecological risk assessment, and other methods. The results demonstrated that the main chemical and mineralogical composition of various molybdenum tailings in Shaanxi Province is similar, and the predominant mineral composition is muscovite, quartz, microcline, and calcite. The potential ecological risk of heavy metals in six molybdenum tailings is high, while Pb and Cd are the main pollution risk elements. Molybdenum tailings contain considerable amounts of critical minerals with huge potential economic value, and molybdenum tailings with high environmental hazards could be converted into a possible source for critical minerals by recovering the critical minerals and repurposing the secondary tailings as an additive or cement substitute. This study provides an innovative idea for the pollution treatment of molybdenum tailings and indicates the prospect of molybdenum tailings as a secondary source for critical minerals., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

The severity of soil molybdenum (Mo) pollution is increasing, and effective management of contaminated soil is essential for the sustainable development of soil. To investigate this, a pot experiment was carried out to assess the impact of different rates of humic acid (HA) and fulvic acid (FA) on the mobility of Mo in soil solution and its uptake by alfalfa, wheat and green bristlegrass. The concentration of Mo in Plants and soil was determined using an Atomic Absorption Spectrophotometer. The findings revealed that the application of HA led to an increase in Mo accumulation in the shoot and root of green bristlegrass and wheat, ranging from 10.56 % to 28.73 % and 62.15-115.79 % (shoot), and 17.52-46.53 % and 6.29-81.25 % (root), respectively. Nonetheless, the use of HA resulted in a slight inhibition of plant Mo uptake, leading to reduced Mo accumulation in alfalfa roots compared to the control treatment (from 3284.49 mg/kg to 2140.78-2813.54 mg/kg). On the other hand, the application of FA decreased Mo accumulation in the wheat shoot (from 909.92 mg/kg to 338.54-837.45 mg/kg). Furthermore, the bioavailability of green bristlegrass (with HA) and wheat (with FA) decreased, and the percentage of residual fraction of Mo increased (from 0.39 % to 0.78-0.96 %, from 3.95 % to 3.97∼ 4.34 %). This study aims to elucidate the ternary interaction among Mo, humic substances, and plants (alfalfa, wheat, and green bristlegrass), to enhance both the activation and hyperaccumulation of Mo simultaneously., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Evidence increasingly suggests molybdenum exposure at environmental levels is still associated with adverse human health, emphasizing the necessity to establish a more protective reference dose (RfD). Herein, we conducted a study measuring 15 urinary metals and 30 clinical health indicators in 2267 participants residing near chemical enterprises across 11 Chinese provinces to investigate their relationships. The kidney and cystatin-C emerged as the most sensitive organ and critical effect indicator of molybdenum exposure, respectively. Odds of cystatin-C-defined chronic kidney disease (CKD) in the highest quantile of molybdenum exposure significantly increased by 133.5% (odds ratio [OR]: 2.34, 95% CI: 1.78, 3.11) and 75.8% (OR: 1.76, 95% CI: 1.24, 2.49) before and after adjusting for urinary 14 metals, respectively. Intriguingly, cystatin-C significantly mediated 15.9-89.5% of molybdenum's impacts on liver and lung function, suggesting nephrotoxicity from molybdenum exposure may trigger hepatotoxicity and pulmonary toxicity. We derived a new RfD for molybdenum exposure (0.87 μg/kg-day) based on cystatin-C-defined estimated glomerular filtration rate by employing Bayesian Benchmark Dose modeling analysis. This RfD is significantly lower than current exposure guidance values (5-30 μg/kg-day). Remarkably, >90% of participants exceeded the new RfD, underscoring the significant health impacts of environmental molybdenum exposure on populations in industrial regions of China., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The issue of potentially toxic elements (PTEs) contamination of regional soil caused by mining activities and tailings accumulation has attracted wide attention all over the world. The East Qinling is one of the three main molybdenum mines in the world, and the concentration of PTEs such as Hg, Pb and Cu in the slag is high. Quantifying the amount of PTEs contamination in soil and identifying potential sources of contamination is vital for soil environmental management. In the present investigation, the pollution levels of 8 PTEs in the Qinling molybdenum tailings intensive area were quantitatively identified. Additionally, an integrated source-risk method was adopted for resource allocation and risk assessment based on the PMF model, the ecological risk, and the health risk assessment model. The mean concentrations of Cu, Ni, Pb, Cd, Cr, Zn, As, and Hg in the 80 topsoil samples ranged from 0.80 to 13.38 times the corresponding background values; notably high levels were observed for Pb and Hg. The source partitioning results showed that PTEs were mainly affected by four pollution sources: natural and agricultural sources, coal-burning sources, combined transport and mining industry sources, and mining and smelting sources. The health risk assessment results revealed that the risks of soil PTEs for adults are acceptable, while the risks for children exceeded the limit values. The obtained results will help policymakers to obtain the sources of PTEs of tailing ponds intensive area. Moreover, it provides priorities for the governance of subsequent pollution sources and ecological restoration., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Objective: To establish an analytical method for determining the migration of 24 elements in Yixing clay pottery in 4% acetic acid simulated solution by inductively coupled plasma mass spectrometry., Methods: Four types of Yixing clay pottery, including Yixing clay teapot, Yixing clay kettle, Yixing clay pot, and Yixing clay electric stew pot, were immersed in 4% acetic acid as a food simulant for testing. The migration amount of 24 elements in the migration solution was determined using inductively coupled plasma mass spectrometry., Results: Lithium, magnesium, aluminum, iron, and barium elements with a mass concentration of 1000 μg/L; Lead, cadmium, total arsenic, chromium, nickel, copper, vanadium, manganese, antimony, tin, zinc, cobalt, molybdenum, silver, beryllium, thallium, titanium, and strontium elements within 100 μg/L there was a linear relationship within, the r value was between 0.998 739 and 0.999 989. Total mercury at 5.0 μg/L, there was a linear relationship within, the r value of 0.995 056. The detection limit of the elements measured by this method was between 0.5 and 45.0 μg/L, the recovery rate was 80.6%-108.9%, and the relative standard deviation was 1.0%-4.8%(n=6). A total of 32 samples of four types of Yixing clay pottery sold on the market, including teapots, boiling kettles, casseroles, and electric stewing pots, were tested. It was found that the migration of 16 elements, including beryllium, titanium, chromium, nickel, cobalt, zinc, silver, cadmium, antimony, total mercury, thallium, tin, copper, total arsenic, molybdenum, and lead, were lower than the quantitative limit. The element with the highest migration volume teapot was aluminum, magnesium, and barium; The kettle was aluminum and magnesium; Casserole was aluminum, magnesium, and lithium; The electric stew pot was aluminum., Conclusion: This method is easy to operate and has high accuracy, providing an effective and feasible detection method for the determination and evaluation of element migration in Yixing clay pottery.

Previous studies have revealed links between metal(loid)s and health problems; however, the link between metal(loid)s and obesity remains controversial. We evaluated the cross-sectional association between metal(loid) exposure in whole blood and obesity among the general population. Vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), molybdenum (Mo), cadmium (Cd), antimony (Sb), thallium (T1), and lead (Pb) were measured in 3029 subjects in Guangdong Province (China) using ICP-MS. The prevalence of overweight and obesity (OWO) and abdominal obesity (AOB) was calculated according to body mass index (BMI) and waist circumference (WC), respectively. Multivariate analysis showed that elevated blood Cu, Cd, and Pb levels were inversely associated with the risk of OWO, and these associations were confirmed by a linear dose-response relationship. Elevated blood Co concentration was associated with a decreased risk of AOB. A quantile g-computation approach showed a significantly negative mixture-effect of 13 metal(loid)s on OWO (OR: 0.96; 95% CI: 0.92, 0.99). Two metals-Ni and Mo-were inversely associated with the risk of OWO but positively associated with AOB. We cross-grouped the two obesity measurement types and found that the extremes of metal content were present in people with AOB only. In conclusion, blood Cu, Mo, Ni, Cd, and Pb were inversely associated with the risk of OWO. The presence of blood Co may be protective, while Ni and Mo exposure might increase the risk of AOB. The association between metal(loid) exposure and obesity warrants further investigation in longitudinal cohort studies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

As a key component of plant nitrogen-fixing enzymes and a variety of human coenzyme factors, molybdenum (Mo) plays an essential role in supporting both plant growth and human health. Soil is a key medium for the cycling of Mo in the biosphere. However, the driving anthropogenic and natural factors governing the spatial distribution of Mo in soil and their interactions are not well understood. To determine the factors that affect the spatial patterns of Mo in topsoil, 6980 samples were collected from the Longitudinal Range-Gorge Region (Linshui County, Sichuan Province, China). In this area, tall mountains are adjacent to deep valleys. Topsoil with enriched Mo is mostly distributed in mountainous areas. The most important factors influencing Mo in topsoil are soil parent materials (q = 0.482), altitude (q = 0.256), and soil type (q = 0.259). There are synergistic effects among the various driving factors [q(X1 ∩ X2) > Max[q(X1), q(X2)]]. The Geodetector model was used to validate the magnitude of the interaction effects. The contribution to interacting factors is nonlinearly enhanced when the contribution of a single factor was low (any two factors of aspect, road distance, land use type, and S). The contribution to interacting factors is enhanced bidirectionally when the contribution of a single factor was high (any two factors of altitude, soil type, soil parent material, OM, and TFe 2 O 3 ). When the contribution of one factor is high and the other is low, the contributing to interacting factors is mostly enhanced bidirectionally and a few are nonlinearly enhanced., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Luanchuan is rich in molybdenum resources, and mining activities are frequent, but over-mining can cause serious metal pollution to the local environment. To explore the degree of metal pollution caused by mining activities, the content characteristics and spatial distribution of metals in mining areas were studied by measuring the concentrations of Fe, Mn, Zn, Ba, Mo, Cu, Cr, Co, V, and W in surface water and mosses of mining areas. In addition, the metal pollution index (HPI), contamination factor (CF), and pollution load index (PLI) were used to evaluate metal pollution, and factor analysis was used to analyze the sources of metals. The results of the analysis of surface water at the mine site indicate the most abundant element in surface water, with a maximum concentration of 3713.8 μg/L, and its content far exceeds the water quality standard of Class III of the Environmental Quality Standard for Surface Water. The results of the HPI analysis showed that nearly 90% of the surface water was moderately contaminated (HPI ≥ 15). The results of the analysis of atmospheric deposition at the mine site confirm that the metal elements with a high threat to the atmospheric environment are Mo and W. The results of PLI indicate that the level of atmospheric deposition pollution in the study area is severe (PLI > 4). Factor analysis indicated that rock weathering and mining activities were the main sources of metals. This study provides a theoretical basis for the investigation and control of metal pollution in similar metal mining areas., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

We determined reference intervals (RIs) for concentrations of trace minerals and toxic elements based on liver samples from 122 apparently healthy horses at 2 slaughter facilities in the Netherlands. Samples were collected during the spring and fall of 2021, and the sex and age of the horses were registered upon sampling. Concentrations of arsenic, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, selenium, vanadium, and zinc were measured in liver samples using inductively coupled plasma-mass spectrometry (ICP-MS) after nitric acid digestion. RIs were calculated using Reference Value Advisor software. The concentrations of most elements were not significantly different between sexes or in different seasons. Cadmium concentrations were higher than the European maximum residue limit of 2 mg/kg DW in 89% of livers. Positive significant correlations were observed between some elements (iron, molybdenum, lead, vanadium), and significant negative correlations between others (manganese, iron)., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to research, authorship, and/or publication of this article.

This study examined potentially toxic elements (PTE) of water and sediments in the Darband and Samana streams of Hangu District. Darband and Samana streams are the main fluvial ecosystems of Hangu District, Pakistan, directly or indirectly affecting more than 0.52 Million people. Water and sediment samples were collected and analyzed for PTE utilizing inductively coupled plasma mass spectrometry (ICP-MS). Water characteristics of Darband and Samana streams were noted within the WHO drinking water guidelines, except for Turbidity and sulfate. Most water characteristics showed higher values in the Samana stream than in the Darband stream. Similarly, most of PTE showed higher concentrations in sediments collected from the Samana stream than the Darband stream. For ecological risk evaluation, several pollution indices were employed to assess the eco-toxicological consequences. The highest contamination factor (CF) value of 15 and 20 were exhibited by molybdenum (Mo) in the Samana and Darband streams showing very high contamination. Similarly, the pollution load index (PLI) showed that 24% of the sediment samples were polluted (PLI > 1). Furthermore, a high ecological risk in a range of 160 < ERI < 320 was observed for Mo, while a low ecological risk ERI < 40 was by As for the Darband and Samana streams sediments. Statistical techniques revealed that various anthropogenic sources primarily contaminated in water and sediment. Therefore, this study recommends regular monitoring PTE contaminations in the area to avoid any health hazards in the future., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Background: A reliable and practical method for assessing Cu status in live animals is not available. Blood Cu levels may not accurately reflect the true Cu status of the herd, and can over-predict Cu status during stress and inflammation. On the other hand, assessment of liver Cu is the most reliable indicator of Cu stores, but it is an invasive procedure that requires specialized training. The aim of this study was to evaluate the usefulness of Cu levels in red blood cells to determine the Cu status, with special emphasis in their correlation with erythrocyte Cu, Zn superoxide dismutase enzyme activity (ESOD), in bovines with Cu deficiency induced by high molybdenum and sulfur levels in the diet., Methods: Three similar assays were performed, with a total of twenty eight calves. The Cu-deficient group (n = 15) received a basal diet supplemented with 11 mg of Mo/kg DM as sodium molybdate, and S as sodium sulfate. The control group (n = 13) received a basal diet supplemented with 9 mg of Cu/kg DM as copper sulfate. Samples of blood and liver were taken every 28-35 days. Cu levels were measured in liver (expressed as µg/g DM), plasma (expressed as µg/dl), and erythrocytes (expressed as µg/g Hb) by flame atomic absorption spectroscopy. Superoxide dismutase (SOD1) activity was determined in red blood cells and was expressed as IU/mg hemoglobin. InfoStat Statistical Software 2020 was used for the statistical analysis. Cu levels in plasma, red blood cells and liver, and ESOD activity were analyzed by ANOVA. The correlation between erythrocyte Cu levels and the rest of the parameters were analyzed by Pearson Correlation test. Unweighted Least Squares Linear Regression of SOD1 was developed. The autocorrelation between the monthly measurements was also determined by Durbin-Watson test and autocorrelation function., Results: The assays lasted 314-341 days, approximately. Levels indicative of Cu deficiency for bovines were detected at 224 days (23 ± 11.6 µg/g DM) for liver Cu concentration; and at 198 days (55 ± 10.4 µg/dl) for plasma Cu concentration, in Cu-deficient animals. Liver and plasma Cu values indicative of Cu deficiency were not observed in the control group. Pearson Correlation test indicated that all indices of Cu status used in this study were significantly correlated. The highest value was obtained between ESOD and red blood Cu (0.74). There was a significant correlation between red blood Cu and plasma Cu (0.65), and with hepatic Cu (0.57). ESOD activity showed a similar significant positive correlation with liver Cu concentrations and with plasma Cu (0.59 and 0.58, respectively)., Conclusion: The extremely low levels of liver and plasma Cu, the ESOD activity, erythrocyte Cu levels, and the periocular achromotrichia observed in the Cu-deficient animals showed that the clinic phase of Cu deficiency was reached in this group. The ESOD activity and erythrocyte Cu levels showed a strong association, indicating that the values of erythrocyte Cu may serve as an effective tool in assessing Cu status and diagnose a long-term Cu deficiency in cattle., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier GmbH. All rights reserved.)

The environmental risks associated with the storage, reuse, and disposal of unencapsulated reclaimed asphalt pavement (RAP) has been previously examined, but because of a lack of standardized column testing protocols and recent interest on emerging constituents with higher toxicity, questions surrounding leaching risks from RAP continue. To address these concerns, RAP from six, discrete stockpiles in Florida was collected and leach tested following the most up-to-date, standard column leaching protocol - United States Environmental Protection Agency (US EPA) Leaching Environmental Assessment Framework (LEAF) Method 1314. Sixteen EPA priority polycyclic aromatic hydrocarbons (PAHs), 23 emerging PAHs, identified through relevance in literature, and heavy metals were investigated. Column testing showed minimal leaching of PAHs; only eight compounds, three priority PAHs and five emerging PAHs, were released at quantifiable concentrations, and where applicable, were below US EPA Regional Screening Levels (RSL). Though emerging PAHs were identified more frequently, in most cases, priority compounds dominated contributions to overall PAH concentration and benzo(a)pyrene (BaP) equivalent toxicity. Except for arsenic, molybdenum, and vanadium in two samples, metals were found below limits of detection (LOD) or below risk thresholds. Arsenic and molybdenum concentrations diminished over time with increased exposure to liquid, but elevated vanadium concentrations persisted in one sample. Further batch testing linked vanadium to the aggregate component of the sample, unlikely to be encountered in typical RAP sources. As demonstrated by generally low constituent mobility observed during testing, the leaching risks associated with the beneficial reuse of RAP are limited, and under typical reuse conditions, factors of dilution and attenuation would likely reduce leached concentrations below relevant risk-based thresholds at a point of compliance. When considering emerging PAHs with higher toxicities, analyses indicated minimal impact to overall leachate toxicity, further suggesting that with proper management, this heavily recycled waste stream is unlikely to pose leaching risk., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Investigation of the inherent relationship between soil physicochemical properties and pollutant's bioaccessibility (BAc) by analyzing different soil types may produce erroneous results or bias, owing to the complexity of natural soil characteristics. However, use of single factor analysis (e.g., soil pH, organic matter) facilitates evaluation of the transition. In this study, the inherent relationship between soil properties and the BAc of molybdenum (Mo) was evaluated in two typical variable-charge soils (Ferralosol and Ferrosol) and constant-charge soils (Alfisol and Inceptisol) spiked with Mo after adjusting their pH and organic carbon content. The Unified Bioaccessibility Research Group of Europe (BARGE) Method (UBM) was applied to evaluate the BAc of Mo in the gastric and intestinal phase (GP and IP, respectively). Isothermal adsorption experiment, Tessier sequential extraction, and field emission scanning electron microscope-energy dispersive spectroscopy (FESEM-EDS) analysis were conducted on these spiked soils. The results indicated that the BAc of Mo in IP (27.42-80.41%) was significantly higher than that in GP (2.52-28.53%). A significantly lower level of BAc of Mo was found in the variable-charge soils, when compared with that in the constant-charge soils. Furthermore, significant negative correlations were identified between the BAc and adsorption of Mo, which decreased with soil pH. These negative correlations can be attributed to the increase in soil negative charge density and enhancement of Mo desorption by hydroxyl, which reinforce the repulsion between Mo and soil particles with increasing soil pH; this was further confirmed by the decrease in Mo adsorption with Alfisol pH. The Mo fractions and FESEM-EDS patterns confirmed that the BAc of Mo in GP was negatively correlated with soil organic carbon (SOC) content, possibly owing to an increase in Mo retention by SOC. These findings indicated that the health risk of Mo contamination in low pH and SOC-rich variable-charge soil is relatively low, thus providing references for rationalizing risk assessment and remediating Mo-polluted soil., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Molybdenum (Mo) is a strategic element but has a notably low concentration at the Earth's surface. Consequently, competition for molybdenum resources at the national strategic level has begun to emerge, and in recent years, large-scale mining has led to the gradual depletion of molybdenum deposit resources. Here, thirty-four element enrichment patterns of Ordovician and Silurian stone coals in central China are reported. Molybdenum is the most enriched element, with an average of 208 mg/kg (58.2-440 mg/kg), which is 99 times the global hard coal average, and this molybdenum enrichment is associated with Ba-Ga-U-Cr-Na-K--Cu-Se-Zn enrichment and elevated SiO 2 , CaO, K 2 O, MgO, Na 2 O, MnO and P 2 O 5 concentrations. These analyses reveal four stone coal samples with molybdenum concentrations of 260, 312, 403 and 440 mg/kg, which meet the grade for the molybdenum mineral exploitation formulated standard, indicating that the Ordovician and Silurian stone coal deposits should be considered promising alternative sources of molybdenum. The crude reserve estimate of molybdenum is approximately 29.2 × 10 4 tons. The anomalous molybdenum in the studied stone coal was sourced from a complex combination of hydrothermal fluids, original biomass and terrigenous materials. The unique paleogeographic location and geological structure in central China resulted in the anomalous molybdenum concentrations in the stone coal forming at that time, producing a unique type of coal-hosted molybdenum deposit. Future studies will consider the ecological effects of the molybdenum extraction mode and the cost savings effects of extracting molybdenum from stone coal. A comprehensive utilization plan is also needed. Next, a thorough study of molybdenum exploration related to black rock series must be performed to increase the total molybdenum resources and support Chinese international competitiveness., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Molybdenum disulfide (MoS 2 ) nanosheets have been used extensively in a variety of fields including medical and industrial. However, little is known about their toxicity effects, especially to edible plants. In this greenhouse study, maize (Zea mays) seedlings were exposed for 4 weeks, through the soil route, to 10 and 100 mg/kg of 2H MoS 2 nanosheets. Plant growth, physiological parameters (chlorophyll, antioxidants, and MDA), along with Mo and nutrient element contents were determined in plant tissues. Results showed that at both doses, the nanosheets decreased plant growth. Inductively coupled plasma-mass spectrometry data also showed that both 2H MoS 2 concentrations allowed Mo absorption and translocation by maize plants. Additionally, at 100 mg/kg the nanosheets significantly reduced Ca, Mg, Mn, and Zn in leaves, and Na in roots. Gene sequencing data of 16S rRNA showed, that MoS 2 nanosheets changed the soil microbial community structure, compared with the untreated control. In addition, nitrogen-fixing microorganisms such as Burkholderiales, Rhizobiales and Xanthobacteraceae were enriched. Overall, the data suggest that, even at low dose (10 mg/kg), the 2H MoS 2 nanosheets perturbed both the nutrient uptake by maize plants and the soil microbial communities., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The relationship between trace elements and neurological development is an emerging research focus. We performed a case-control study to explore (1) the differences of 13 trace elements chromium (Cr), manganese (Mn), cobalt (Co), zinc (Zn), arsenic (As), selenium (Se), molybdenum (Mo), cadmium (Cd), stannum (Sn), stibium (Sb), mercury (Hg), titanium (TI), and plumbum (Pb) concentration in whole blood and urine between autism spectrum disorder (ASD) children and their typical development peers, and (2) the association between the 13 trace elements and core behaviors of ASD. Thirty ASD subjects (cases) and 30 age-sex-matched healthy subjects from Baise City, Guangxi Zhuang Autonomous Region, China, were recruited. Element analysis was carried out by inductively coupled plasma-optical emission spectrometry. Autistic behaviors were assessed using Autism Behavior Checklist (ABC), Childhood Autism Rating Scale (CARS), and Children Neuropsychological and Behavior Scale (CNBS). The whole blood concentrations of Mo (p = 0.004), Cd (0.007), Sn (p = 0.003), and Pb (p = 0.037) were significantly higher in the ASD cases than in the controls. Moreover, Se (0.393), Hg (0.408), and Mn (- 0.373) concentrations were significantly correlated between whole blood and urine levels in ASD case subjects. There were significant correlations between whole blood Sb (0.406), Tl (0.365), Mo (- 0.4237), Mn (- 0.389), Zn (0.476), and Se (0.375) levels and core behaviors of ASD. Although the mechanism of trace element imbalance in ASD is unclear, these data demonstrate that core behaviors of ASD may be affected by certain trace elements. Further studies are recommended for exploring the mechanism of element imbalance and providing corresponding clinical treatment measures., (© 2022. The Author(s).)

This study investigated the influence of natural weathering on the mineralogical, physical, and chemical properties of molybdenum tailings from Shaanxi Province, China, stored at different stacking ages. The results showed that the mineralogical and chemical compositions of the molybdenum tailings remained stable after stacking for different years. The analysis of bulk density, porosity, field moisture capacity, and aggregate characteristics indicated that the physical structure of the molybdenum tailings was similar to a nearby soil with increasing stacking age in spite of a time-consuming process. In addition, 10 years of the natural weathering process resulted in the formation of more aggregates with the surface of microaggregates roughened, and displayed more debris and fine particles than stocking for 1 year. The findings showed that the bulk density of molybdenum tailings reduced from 1.45 to 1.42 g/cm 3 after 10 years of storage, while its porosity rose from 46.5 to 49.4%. The fraction of large aggregate (> 0.25 mm) and mean weight diameter increased from 7.91 to 42.07% and from 0.1482 to 0.1864 mm, respectively, which demonstrated that the natural weathering significantly improved the physical properties of the aggregate and enhanced the structural stability. Thus, natural weathering provides an ecological basis for restoring and reconstructing the soil ecosystem in molybdenum tailings. The results confirmed that long-term deposition can improve the soil structure of tailings, which provides a reference for further research on restoring and reconstructing the soil ecosystem in molybdenum tailings., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background and Aim: This study aims to evaluate the toxic metal and trace element concentrations in breast milk obtained from new-born nursing mothers in rural Giresun province, located on the coast of the Black Sea., Methods: Milk samples were randomly collected once from early lactation of 50 nursing mothers. Inductively coupled plasma mass spectrometry was used to analyse the concentrations of iron (Fe), nickel (Ni), manganese (Mn), cobalt (Co), chromium (Cr), copper (Cu), zinc (Zn), arsenic (As), molybdenum (Mo), cadmium (Cd) and lead (Pb) in the breast milk. Shapiro-Wilk test was used to evaluate the distribution of data. The Pearson-J correlation was used for normally distributed elements, and Spearman correlation analysis was used for others., Results: The mean amounts of elements were 3.36 µg kg -1 of Cr, 9.26 µg kg -1 of Mn, 797 µg kg -1 of Fe, 1.99 µg kg -1 of Ni, 5.92 µg kg -1 of Cu, 379 µg kg -1 of Zn and 2.23 µg kg -1 of Pb. Co, As, Mo and Cd concentrations were below the detection limit. A highly significant correlation was found between iron and Nickel in breast milk., Conclusion: Our findings were evaluated in comparison with the WHO data, and whether they were in accordance with the recommended Dietary Reference Intake (DRI) values for 0-6-months-old infants was calculated. Pb levels were similar to those of WHO, while As and Cd were below the measurable limit. Fe, Mn, and Cr concentrations were higher than WHO data, while Co, Ni, Cu and Zn were lower. This research is the first study conducted in this region., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier GmbH. All rights reserved.)

The groundwater resources of mining areas have been in a challenging condition in terms of metal pollution and human health. Therefore, this study investigated the concentration of cobalt (Co), molybdenum (Mo), selenium (Se), tin (Sn), and antimony (Sb) in groundwater samples (wells, qanats, and springs) in a heavily contaminated mining district, South Khorasan, Eastern Iran. Human health risk of the studied metals to target groups was assessed, and water quality of the studied groundwater was investigated in the study area. A total of 367 sampling sites (279 wells, 74 qanats, and 14 springs) in South Khorasan Province were selected to collect the groundwater samples from June to July 2020. Sampling was performed thrice for each sampling point, and hydrochemical parameters were evaluated using a portable multiparameter. Inductively coupled plasma mass spectrometry (ICP-MS) was used to detect the metal concentrations. Results showed an order of Se > Mo > Sn > Co > Sb, and hazard index (HI) demonstrated a warning condition for south of South Khorasan (drinking application), southwest of South Khorasan (Irrigation application), and east and center of South Khorasan (drinking-irrigation application). Hydrochemical parameters showed a classification of "Na + K type" and "Mixed Ca-Mg-Cl type" with an overall group of "Na-Cl-HCO 3 " for sampled waters. Ficklin-Caboi diagram depicted a classification of "near-neutral low metal," and Schoeller diagram classified studied groundwater as "good" for drinking and irrigation consumptions and "Na-Cl" type based on ion balance diagram. Based on the correlation analysis, positive relationships were recorded among EC, TDS, Cl - , Na + , sulfate, Ca 2+ , salt, total hardness, Mg 2+ , ammonia, and K + measured in the water samples. In essence, arid regions of the world greatly rely upon groundwater resources for drinking and irrigation consumptions, and mining districts with a heavy load of active mines can be a serious threat to the groundwater quality and human health., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Inhalable particulate matter (PM) is a health concern, and people living in large cities such as Bangkok are exposed to high concentrations. This exposure has been linked to respiratory and cardiac diseases and cancers of the lung and brain. Throughout 2018, PM was measured in northern Bangkok near a toll road (13.87°N, 100.58°E) covering all three seasons (cool, hot and rainy). PM 10 was measured in 24- and 72-h samples. On selected dates aerodynamic size and mass distribution were measured as 3-day samples from a fixed 5th floor inlet. Particle number concentration was measured from the 5th floor inlet and in roadside survey measurements. There was a large fraction of particle number concentration in the sub-micron range, which showed the greatest variability compared with larger fractions. Metals associated with combustion sources were most found on the smaller size fraction of particles, which may have implications for associated adverse health outcomes because of the likely location of aerosol deposition in the distal airways of the lung. PM 10 samples varied between 30 and 100 μg m -3 , with highest concentrations in the cool season. The largest metal fractions present in the PM 10 measurements were calcium, iron and magnesium during the hot season with average airborne concentrations of 13.2, 3.6 and 2.0 μg m -3 , respectively. Copper, zinc, arsenic, selenium, molybdenum, cadmium, antimony and lead had large non-crustal sources. Principal component analysis (PCA) identified likely sources of the metals as crustal minerals, tailpipe exhaust and non-combustion traffic. A health risk analysis showed a higher risk of both carcinogenic and non-carcinogenic health effects in the drier seasons than the wet season due to ingestion of nickel, arsenic, cadmium and lead., (© 2022. The Author(s).)

Analysis of hair to gain insight into the trace mineral status and exposure to toxic heavy metals of horses is attractive because hair is an easily accessible sample material. To investigate the potential value of hair analysis in horses for determination of trace mineral and heavy metal concentrations, we analyzed mane hair and liver samples from 62 horses presented for slaughter at a facility in the Netherlands that receives horses from all regions of the country. Hair samples were cleaned in warm water. After acid digestion of hair and liver specimens, we quantified, with inductively coupled plasma-mass spectrometry, arsenic, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, selenium, vanadium, and zinc in the digests. Based on Pearson product moment correlations, we found no statistically significant correlations between concentrations of trace minerals in liver and hair, with the exception of a slight correlation for copper that was too weak to be of clinical relevance. Our results do not support the use of hair to determine trace mineral status and exposure to toxic heavy metals in the horse under field conditions.

Molybdate (MoO 4 ) and tetrathiomolybdate (MoS 4 ) supplementation of rats via drinking water had opposite effects on the establishment of Nippostrongylus brasiliensis larvae but both induced hypercupraemia, temporarily inhibited activities of superoxide dismutase in liver and duodenum after infection and enlarged the femoral head. Effects of MoO 4 and MoS 4 on activities of caeruloplasmin oxidase (CpO) in plasma, erythrocyte superoxide dismutase (ESOD) and tissue copper (Cu) and molybdenum (Mo) were compared to test the hypothesis that species lacking a rumen can thiolate MoO 4 . Three groups of 18 immature Wistar rats were given Mo (70 mg/L as MoO 4 ) or MoS 4 (5 mg/L) via drinking water or remained untreated; all received a commercial, cubed diet and 12 from each group were infected with larvae of N. brasiliensis. Rats were killed 7-9 days later and liver, kidney, spleen, heart, muscle (quadriceps), brain and bone (femur) removed for Cu and Mo analysis. Plasma Cu was greatly increased by MoO 4 and MoS 4 , without changing CpO activity, but the effect was more variable with MoO 4 and accompanied by a smaller decrease in ESOD. Tissue Cu and Mo were increased by MoS 4 in all tissues examined except brain and bone, correlating with plasma Cu and with each other; relationships were strongest in spleen, followed by kidney. MoO 4 also increased soft tissue Cu and Mo but increases were generally smaller than those induced by MoS 4 and correlations between the two elements and with plasma Cu generally weaker. Since hypercupraemia and correlated increases in liver and kidney Cu and Mo are characteristic of systemic thiomolybdate (TM) exposure, we conclude that MoO 4 was partially thiolated to give a different TM profile from that produced by MoS 4 . The pathophysiological significance of systemic exposure to di- and tri-TM merits investigation in non-ruminants as agents of chelation therapy and in ruminants as agents of short-lived TM toxicity on Mo-rich pastures., Competing Interests: Conflict of Interest Statement The authors declared no potential conflicts of interest with respect to the research, authorship or publication of this manuscript., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Human beings are exposed to heavy metals through various ways in daily life. However, the effect of heavy metal mixtures on muscle strength in children and adolescents remains unclear. We aimed to investigate the relationship of exposure to heavy metal mixtures (barium, cadmium, cobalt, manganese, molybdenum, lead, antimony, strontium, tin, thallium, tungsten, uranium, and cesium) with muscle strength in children and adolescents. A total of 1357 (boys, 50.8%) participants aged between 8 and 17 were extracted from the National Health and Nutrition Examination Surveys 2011-2014. Urine metals were measured by inductively coupled plasma-mass spectrometry. Muscle strength was measured through a grip test using a handgrip dynamometer. Weighted quantile sum regression was performed to estimate the mixture effect of urinary metals on muscle strength. After adjusting for potential confounders, comparing participants in the highest versus lowest quartiles of cobalt, molybdenum, lead, antimony, strontium, thallium, and cesium, the handgrip strength decreased by - 4.48 kg (95% CI: - 6.93, - 2.03), - 6.13 kg (- 8.76, - 3.51), - 2.26 kg (- 4.22, - 0.30), - 2.38 kg (- 4.68, - 0.08), - 2.29 kg (- 4.45, - 0.13), - 4.78 kg (- 7.13, - 2.44), and - 5.68 kg (- 9.20, - 2.17), respectively. Furthermore, exposure to a mixture of metals were also significantly associated with decreased muscle strength (β: - 2.62 kg; 95% CI: - 3.71, - 1.54). Findings from the present study suggest that higher heavy metal exposure and the exposure levels of a mixture of metals in urine are inversely related to handgrip strength, implying that children's grip strength is not entirely explained by energy intake or lack of exercise, but may be related to environmental pollutants., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Developing high-performance adsorbent for hexavalent chromium (Cr(VI)) elimination presents an enticing prospect in environmental remediation. Herein, three-dimensional flowerlike nanospheres composed of molybdenum disulphide and polypyrrole (MoS 2 @PPy) were successfully prepared via a one-pot hydrothermal and subsequent carbothermal reduction process for the removal of Cr(VI). The effects of pH, adsorbent dosage, co-existing ions, initial Cr(VI) concentration and temperature were investigated systematically by batch experiments. Benefiting from the incorporation of MoS 2 , the obtained MoS 2 @PPy composites showed a dramatic increase of specific surface area (149.82 m 2 ·g -1 ) and adsorption capacity (230.97 mg·g -1 ) when compared with the pure PPy nanoparticles. Based on the thermodynamics study and X-ray photoelectron spectroscopy analyses, the removal process of Cr(VI) was proved to be exothermic and spontaneous, and accessible under-coordinated Mo(IV) and pyrrolic N groups coupled with redox reactions were conducive to the efficient removal of Cr(VI). Attractively, the MoS 2 @PPy acted as the electron donor could also activate peroxymonosulphate for the efficient degradation of organic contaminants. These results suggested that the MoS 2 @PPy was promising in Cr(VI) elimination and other kinds of organic pollutants removal in wastewater.

Procedures for the analysis of molybdenum oxide by of inductively coupled plasma atomic emission spectroscopy ( ICP-AES) and mass spectrometry ( ICP-MS) are proposed on the basis of preliminary extraction separation of molybdenum from impurity elements. To separate 39 impurity elements (Li, Be, Na, Mg, Al, K, Ca, Sc, Ti, Cr, Mn, Fe, Co, Ni, Zn, Ga, Rb, Sr, Y, Cd, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Pb, Bi, Th, and U), the extraction of molybdenum from hydrochloric acid solutions using 5- n-pentylthio-8-hydroxyquinoline was used. The capacities of both methods ICP-AES and ICP-MS in the analysis of molybdenum oxide analysis were examined without the removal of the matrix and after the extraction separation of molybdenum. [ABSTRACT FROM AUTHOR]

Objectives: Occupational exposure to molybdenum has been poorly documented to date. Here, we present a retrospective study evaluating urinary molybdenum concentration before and after shift over a period of 2 years in exposed workers., Methods: This retrospective study was conducted across eight industrial sites in France and included all workers undergoing medical follow-up for occupational molybdenum exposure. A mean of six sequential samples (before and after shift) was performed for each worker. The urinary molybdenum concentration was determined using a validated method of inductively coupled plasma-mass spectrometry. A mixed linear model was built and linear regression was used to verify the extent to which the urinary molybdenum concentration depends on the age of the workers and the sampling period. Additionally, an analysis based on individual trajectory was also performed., Results: Seventy-seven workers were included in the present study. Post-shift urinary molybdenum concentrations were significantly higher than pre-shift values [median (95th percentile) 37.9 (91.1), versus 60.6 (190.0) µg g-1 creatinine, respectively, P < 0.009]. No accumulation of molybdenum over time was observed. The urinary molybdenum concentrations were not influenced by age. Four workers presented high post-shift values as a result of not adhering to protection measures (maxima of 529.8, 359.7, 386.3, and 1459.7 µg g-1 creatinine, respectively)., Conclusions: To our knowledge, this is the first study of occupational molybdenum exposure in France to include an individual trajectory analysis. No accumulation of molybdenum was seen but high post-shift molybdenum urinary concentrations were observed for some workers. The study emphasizes the importance of molybdenum monitoring in exposed workers., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.)

Some regions of Argentina are affected by high concentrations of molybdenum, arsenic and vanadium from natural sources in their groundwater. In particular, Mo levels in groundwater from Eduardo Castex (La Pampa, Argentina) typically exceed the guidelines for drinking water formerly established by WHO at 70 μg/L. Therefore, this study investigated the uptake of Mo in plants, using cress (Lepidium sativum L.) as a model using hydroponic experiments with synthetic solutions and groundwater from La Pampa. Cress grown from control experiments (150 μg/L Mo, pH 7) presented an average Mo concentration of 35.2 mg/kg (dry weight, d.w.), higher than the typical total plant range (0.7-2.5 mg/kg d.w.) in the literature. Using pooled groundwater samples (65.0-92.5 μg/L Mo) from wells of La Pampa (Argentina) as growth solutions resulted in significantly lower cress Mo levels (1.89-4.59 mg/kg d.w.) than were obtained for synthetic solutions of equivalent Mo concentration. This may be due to the high levels in these groundwater samples of As, V, Fe and Mn which are known to be associated with volcanic deposits. This research addressed the hitherto scarcity of data about the effect of various physicochemical parameters on the uptake of Mo in plants., (© 2021. The Author(s).)

In this investigation, a novel alginate complex was developed for the selective separation of molybdenum (Mo(VI)) ions from some rare earth elements (REEs). In this regard, alginate as a natural polysaccharide was impregnated and modified with 2-hydroxy-5-nonylacetophenone oxime (Lix-84) and characterized using FT-IR, TGA/DTA and SEM-EDX. The relation between medium acidity, adsorption kinetics, sorbent dose, isotherm models, temperature and Mo(VI) recovery was investigated. It was concluded that the impregnation stage promoted the Mo(VI) separation. The kinetics and isotherm data were well-fitted and matched with the pseudo-first-order model and Langmuir isotherm model; respectively. The Langmuir maximum adsorption capacity of Mo(VI) reached 72.2 mg/g. The developed material showed excellent separation performance towards Mo ions over the investigated REEs. The desorption and recovery of the loaded Mo(VI) ions were achieved using 1.0 M HCl. Reutilization of Alg/Lix-84 was confirmed up to three adsorption-desorption cycles with no damage of the beads as proved with SEM analysis. The adsorption mechanism of molybdenum onto Alg/Lix-84 was elucidated through FTIR and XPS measurements and was found to be governed by both electrostatic interaction and ion exchange. Therefore, the developed material has a promising potential for the selective separation of molybdenum from REEs-containing solution., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Many nanoscale biomaterials fail to reach the clinical trial stage due to a poor understanding of the fundamental principles of their in vivo behaviour. Here we describe the transport, transformation and bioavailability of MoS 2 nanomaterials through a combination of in vivo experiments and molecular dynamics simulations. We show that after intravenous injection molybdenum is significantly enriched in liver sinusoid and splenic red pulp. This biodistribution is mediated by protein coronas that spontaneously form in the blood, principally with apolipoprotein E. The biotransformation of MoS 2 leads to incorporation of molybdenum into molybdenum enzymes, which increases their specific activities in the liver, affecting its metabolism. Our findings reveal that nanomaterials undergo a protein corona-bridged transport-transformation-bioavailability chain in vivo, and suggest that nanomaterials consisting of essential trace elements may be converted into active biological molecules that organisms can exploit. Our results also indicate that the long-term biotransformation of nanomaterials may have an impact on liver metabolism.

The contamination of soils by heavy metals from the mining industry nowadays is one of the greatest threats to environment and human health. The cleaning of polluted soils using cost-effective and eco-friendly methods such as phytoextraction has wide public recognition. Considering the above-mentioned ones, the objectives of the present study were the identification of Cu and Mo accumulation capability and the phytoextraction potential of Melilotus officinalis and Amaranthus retroflexus as well as the determination of the influence of ammonium nitrate and EDTA on phytoextraction effectiveness. The contaminated soil samples for phytoremediation experiments under ex situ conditions were collected from the surroundings of the Zangezur Copper and Molybdenum Combine, Armenia. During the studies, it was found out that M. officinalis and A. retroflexus are capable of growing in polluted soils. M. officinalis grown in polluted soil had greater ability to accumulate heavy metals in roots, while the ability to transport the copper to aboveground parts was more pronounced in A. retroflexus. During the growing of these plant species for phytoextraction of soils contaminated by copper, it is necessary to use chelates, in particular the EDTA, for the enhancement of the effectiveness of phytoextraction process. EDTA due to chelating influence increased the availability of copper for plants and its mobility in them that lead to greater accumulation of this metal in shoots. The application of chelates did not have a significant impact on molybdenum accumulation intensity in plants; therefore, in case of this metal, it is unreasonable to use additional chelating compounds.

Cadmium (Cd) toxicity causes severe perturbations in nitrogen (N) uptake and assimilation, and thereby interrupts normal plant growth. Molybdenum (Mo), a necessary trace element, plays important roles in N metabolism through regulating N assimilatory enzymes activities and expressions in higher plants. Taking this into account, a pot experiment was performed to explore the role of Mo in alleviating Cd-induced inhibitory effects on physio-biochemical processes, N metabolism, yield attributes and grain quality characters of two fragrant rice cultivars; Guixiangzhan and Meixiangzhan-2. Both the fragrant rice cultivars were treated with two levels of each Cd concentrations (0 and 100 mg/kg) and Mo treatments (0 and 0.15 mg/kg). The results revealed that Cd toxicity significantly reduced (p < 0.05) plant dry biomass, gaseous exchange attributes, chlorophyll contents, N utilizing and assimilatory enzymes activities, 2-acetyl-1-pyrroline (2AP) contents and grain yield in both cultivars; however, more severe inhibitions were observed in Meixiangzhan-2 than Guixiangzhan. Nevertheless, Mo application alleviated Cd stress and enhanced 2AP content and grain yield by 75.05% and 67.94% in Guixiangzhan and 87.71% and 83.51% in Meixiangzhan-2, respectively compared with no Mo application. Moreover, Mo application improved photosynthesis, chloroplast configuration, soluble protein and proline contents and also strengthened the N assimilatory pathway through efficient NO 3 - utilization, higher nitrate reductase, nitrite reductase, glutamine synthetase and glutamate synthase activities and transcript levels under Cd stress. Collectively, our results imply that Mo-induced enhancement in N utilization and assimilation improved yield and grain quality characters of fragrant rice cultivars under Cd stress., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

This study was conducted to assess heavy metals in the overlying water and sediments of Luhun Reservoir, Henan Province, China, which is positioned downstream from a molybdenum (Mo) mining area. The pollution indexes indicated that deposition of all metals may have been affected by the mining area. The single element pollution factor (P i ) of Mo was the highest among all heavy metals, with a mean value of 2.05. However, the sediments were subject to long-term accumulation of metals, particularly Mo, Cd, Pb, and Zn, which originated from anthropogenic sources. The mean individual element potential ecological risk index values for Cd were above 385, while the mean value comprehensive potential ecological risk index was 465, which indicates a high ecological risk. Moreover, the enriched heavy metals had different spatial distributions in the Luhun Reservoir sediments. Finally, Pearson correlation analysis indicated that the Pb was mainly affected by different anthropogenic sources and had no relationship with other metals, which suggests that the influence of mining area on heavy metal concentrations in the reservoir is difficult to disentangle., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Raman spectroscopy was used for the quantitative determination of Mo and W in Mo- and W-supported mesoporous silica (Mo/SBA-15 and W/SBA-15, respectively) and Mo-supported beta zeolite (Mo-BEA). Three Raman quantitative models were developed and optimized for the metal contents of Mo/SBA-15, W/SBA-15, and Mo/BEA. Subsequently, the models were characterized using the root mean square error of calibration (RMSEC), root mean square error of cross-validation (RMSECV), root mean square error of prediction (RMSEP), correlation coefficient, and predicted residual error sum of squares (PRESS) diagnostic function. The calibration range of the models were in the range of approximately 2-40 wt% for the SBA-15 support and 1-21 wt% for the BEA support because the BEA support presented lower Mo absorption than the SBA-15 support. The RMSEC, RMSECV, and RMSEP values were below 1.80% for all developed models. The highest and lowest correlation coefficients corresponded to the W/SBA-15 (0.9984) and Mo/BEA (0.9777) models, respectively. The change in catalyst support affected the mentioned chemometric parameters (Mo/SBA-15 vs. Mo/BEA). Subsequently, Raman spectroscopy combined with the temperature control stage was used to study the calcination of Mo/BEA, Mo/SBA-15, and W/SBA-15 using three-dimensional diagrams, in which the changes in catalyst structure were analyzed as functions of the temperature and time. Raman spectroscopy was determined to be a suitable analytical tool for the quantitative analysis of the metal contents of the catalyst and optimization of the calcination process. Therefore, Raman spectroscopy can be used during catalyst manufacturing.

A new procedure combining dispersive liquid-liquid microextraction and electrothermal atomic absorption spectrometry was proposed for the determination of molybdenum in plants and animal tissue. The optimized conditions for the microextraction procedure were: 150 μL of 0.3 mol L -1 potassium ethyl xanthate (pH 1.4) and 1000 μL of acetonitrile and 50 μL of carbon tetrachloride as dispersive and extractant solvent, respectively. A limit of detection of 0.03 μg kg -1 and a limit of quantification of 0.11 μg kg -1 , as well as an enrichment factor of 200, were achieved employing this procedure. Standard reference materials were used for trueness and precision evaluation. No significant differences were found at the 95% confidence level between certified and obtained values, and the precision expressed as repeatability (s r %) was 4.1% for animal tissue and 4.7% for plant material. The method was successfully applied for the determination of Mo in bovine meat and pasture samples from different livestock establishments., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest regarding the publication of this article., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Lettuce is one of the most popular vegetables, and the market niche of the baby leaf variety is expanding. The manner in which nitrogen (N) is supplied and the available concentration of the micronutrient molybdenum (Mo) affect N metabolism, with reflects on the nutritional quality of that vegetable. Here, two Mo concentrations (0.06 and 0.12 mg/L) and four proportions (%) of nitrate (NO 3 - )/ammonium (NH 4 + )(100/0, 75/25, 50/50, and 25/75) were supplied to hydroponic baby leaf lettuce floating type to evaluate their effects on plant growth and leaf mineral and NO 3 - compositions. Shoot dry mass did not differ among the different treatments, although fresh mass was lower in treatments with larger proportions of NH 4 + . Higher leaf concentrations of NO 3 - were observed in plants treated with 100% N-NO 3 - , but they were still below tolerable limits for human health. The enzyme nitrate reductase was not found to be sensitive to the nitrogen sources or to Mo concentrations. N proportions and Mo concentrations differently affected macro- (C, N, P, K, Ca, Mg, and S) and micronutrients (Cu, Fe, Mn, Mo, and Zn) leaf concentrations. Although treatment with 100% N-NO 3 - favored higher mineral concentrations in lettuce leaves, the addition of 25% N-NH 4 + allowed fresh mass production with the lowest NO 3 - concentrations. As such, and considering the healthy reduction of NO 3 - consumption by humans and the maintenance of plant productivity, the 75/25 NO 3 - /NH 4 + proportion is recommended for the hydroponic cultivation of baby leaf var. Mimosa lettuce. PRACTICAL APPLICATION: We demonstrate a direct link between the constitution of nutrient solution with nitrate accumulation by hydroponic lettuce and indicate the best source of N as well as the concentration of Mn to healthy reduction of NO 3 - consumption by humans and the maintenance of plant productivity., (© 2020 Institute of Food Technologists®.)

Molybdenum (Mo) is an essential nutrient for the proper functioning of some enzymes in living organisms as human beings. Conventional methods for its detection require complicated instrumentations as atomic absorption or mass spectrometers. In this work, a sensitive kinetic fluorescence was developed as an alternative. Gold nanoclusters (AuNCs) with red fluorescence emission were synthesized, and this fluorescence was effectively quenched by iodine through an etching process. It was found that the presence of Mo significantly speeded up a reaction for the generation of iodine, and thus enhanced the quenching. This effect was then adopted for the development of a sensitive fluorescent measurement toward Mo. The method was capable of detecting Mo down to 0.2 nM and was successfully applied for the analyses of mung bean and tea leaf samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Molybdenum dichalcogenides MoX 2 (X=S, Se) have been found to possess intrinsic peroxidase-like activity. However, molybdenum oxides (MoO 2 ) as peroxidase mimetics have not been exploited yet. Herein, MoO 2 nanoparticles were synthesized by a simple hydrothermal method and found to possess the peroxidase-like activity for the first time. MoO 2 nanoparticles could catalyze the oxidation of 3,3',5,5'-tetrametylbenzidine (TMB) by H 2 O 2 to produce a blue-color product (oxTMB). The catalytic property and mechanism were investigated by stead-state kinetics experiment and free radicals scavenging experiment, respectively. Acetylcholinesterase (AChE) could catalyze the hydrolysis of acetylthiocholine chloride (ATCh) into thiocholine (TCh), which could reduce oxTMB to decrease the absorbance in solution. In the presence of AChE inhibitor tacrine, the generation of TCh was inhibited and the absorbance was preserved. Based on these properties, a colorimetric assay method was developed for AChE inhibitor tacrine. This work not only broadens the application of the peroxidase mimetics, but also overcome the disadvantages of traditional methods such as expensive, complex and vulnerable to background interference for colorimetric assay of AChE inhibitor., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Autism Spectrum Disorder (ASD) is a complex disorder with heterogeneous etiology and wide clinical severity which supports the needs of recognizing biological and clinical features in patient subsets. The present study aimed to understand possible associations between the hair levels of metals and essential elements and some specific features of ASD measured by the Autism Diagnostic Observation Schedule (ADOS) that represents the gold-standard instrument to objectively confirm ASD diagnosis., Methods: A cross-sectional study was performed in the province of Catania (Sicily, South Italy). Forty-eight subjects with ASD (70.8% male), aged from 2 to 17 years were studied. Metals (Li, Be, Al, Ni, As, Mo, Cd, Hg, U, Pb) and essential trace elements (Cr, Co, Mn, Zn, Cu, Se) were quantified in hair by inductively coupled plasma mass spectrometry analysis. Participants were characterized by measuring the severity of autism symptoms and cognitive levels., Results: A significant and positive correlation was found between hair metal burden (lead, aluminum, arsenic and cadmium levels) and severity of ASD symptoms (social communication deficits and repetitive, restrictive behaviors). Hair zinc level were inversely related with age while there was a negative, significant association between hair zinc level and severity of autistic symptoms (defective functional play and creativity and increase of stereotyped behavior). Lead, molybdenum and manganese hair levels were inversely correlated with cognitive level (full intelligence quotient) in ASD individuals., Conclusions: The present study suggests the importance to combine metallomics analysis with pertinent disease features in ASD to identify potential environmental risk factors on an individual level possibly in the early developmental period., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

Biological nitrogen fixation (BNF) by microorganisms associated with cryptogamic covers, such as cyanolichens and bryophytes, is a primary source of fixed nitrogen in pristine, high-latitude ecosystems. On land, low molybdenum (Mo) availability has been shown to limit BNF by the most common form of nitrogenase (Nase), which requires Mo in its active site. Vanadium (V) and iron-only Nases have been suggested as viable alternatives to countering Mo limitation of BNF; however, field data supporting this long-standing hypothesis have been lacking. Here, we elucidate the contribution of vanadium nitrogenase (V-Nase) to BNF by cyanolichens across a 600-km latitudinal transect in eastern boreal forests of North America. Widespread V-Nase activity was detected (∼15-50% of total BNF rates), with most of the activity found in the northern part of the transect. We observed a 3-fold increase of V-Nase contribution during the 20-wk growing season. By including the contribution of V-Nase to BNF, estimates of new N input by cyanolichens increase by up to 30%. We find that variability in V-based BNF is strongly related to Mo availability, and we identify a Mo threshold of ∼250 ng·g lichen -1 for the onset of V-based BNF. Our results provide compelling ecosystem-scale evidence for the use of the V-Nase as a surrogate enzyme that contributes to BNF when Mo is limiting. Given widespread findings of terrestrial Mo limitation, including the carbon-rich circumboreal belt where global change is most rapid, additional consideration of V-based BNF is required in experimental and modeling studies of terrestrial biogeochemistry., Competing Interests: The authors declare no competing interest., (Copyright © 2019 the Author(s). Published by PNAS.)

Cu, Fe, Mn, Mo, Selenium (Se), and Zn bioavailability from selenate- and selenite-enriched lettuce plants was studied by in vitro gastrointestinal digestion followed by an assay with Caco-2 cells. The plants were cultivated in the absence and presence of two concentrations (25 and 40 µmol/L of Se). After 28 days of cultivation, the plants were harvested, dried, and evaluated regarding the total concentration, bioaccessibility, and bioavailability of the analytes. The results showed that biofortification with selenate leads to higher Se absorption by the plant than biofortification with selenite. For the other nutrients, Mo showed high accumulation in the plants of selenate assays, and the presence of any Se species led to a reduction of the plant uptake of Cu and Fe. The accumulation of Zn and Mn was not strongly influenced by the presence of any Se species. The bioaccessibility values were approximately 71%, 10%, 52%, 84%, 71%, and 86% for Cu, Fe, Mn, Mo, Se, and Zn, respectively, and the contribution of the biofortified lettuce to the ingestion of these minerals is very small (except for Se and Mo). Due to the low concentrations of elements from digested plants, it was not possible to estimate the bioavailability for some elements, and for Mo and Zn, the values are below 6.9% and 3.4% of the total concentration, respectively. For Se, the bioavailability was greater for selenite-enriched than selenate-enriched plants (22% and 6.0%, respectively), because selenite is biotransformed by the plant to organic forms that are better assimilated by the cells., (© 2019 Institute of Food Technologists®.)

Milk can be considered as an indicator of the degree of environmental contamination of the place where it is produced and this is especially important when assessing its content in toxic metals. Therefore, 36 bovine milk samples from 7 farms with a semi-extensive grazing system were analysed, located in Asturias (Spain), in an area with high probability of being highly contaminated due to a mining zone, with important industrial activity and near high-density highway traffic. The samples were lyophilised to achieve total dehydration, further analysed using inductively coupled plasma mass spectrometry (ICP-MS). The metals titrated were aluminium (Al), arsenic (As), molybdenum (Mo) and mercury (Hg) in the lyophilised samples and subsequently extrapolated their values to whole milk. All samples analysed showed levels of Al and Mo above the limit of detection, with mean values of Al of 140.89 ± 157.07 in liquid milk and 1065.76 ± 1073.45 in lyophilised milk and Mo of 20.72 ± 14.61 μg/kg and 152.26 ± 96.82 μg/kg in whole and lyophilised milk. Only As was detected in four samples with mean values of 18.45 ± 6.89 and 166.45 ± 42.30 μg/kg in liquid and lyophilised milk, respectively, and no Hg was found in any of them. In no case do the values found indicate a significant hazard to the population and are in agreement with those found in other investigations. Although the various anthropogenic activities of the area (industrial, mining, traffic density) could, a priori, indicate a possibly contaminated area.

"Bottom-up" method is a popular approach for the preparation of molybdenum disulfide quantum dots (MoS 2 QDs) benefitting from less time consumption and no high-powered sonication required. But the relatively low fluorescent quantum yield of the obtained MoS 2 QDs and the rare study about their in vivo behavior stimulate us to do more research in this area. In this paper, we proposed a "bottom-up" hydrothermal method to prepare MoS 2 QDs with a quantum yield (QY) of 34.55% by optimizing a series of reaction conditions. The successful fluorescence imaging of tumor cells in vitro and in vivo as well as the systematic in vivo behavior study such as biocompatibility, biodistribution and metabolism route provided the good basis for their wider biomedical applications., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Globally, millions of tons of coal fly ash (CFA) are generated per year, and the majority of this material is usually stored in stock piles or landfills, and in a long-term, it can be an environmental hazard if rainwater infiltrates the ashes. Long-term leaching studies of Brazilian ashes are scarce. The purpose of this study was to evaluate arsenic, cadmium, molybdenum, lead, and zinc leaching behavior from a Brazilian CFA by a column experiment designed to simulate field conditions: slightly acid rain considering seasonality of precipitation and temperature for a long-term leaching period (336 days). All elements were leached from CFA, except lead. Elements leaching behavior was influenced by leaching time, leaching volume, and temperature. Higher leachability of As and Cd from CFA during warm and wet season was observed. Results indicate a potential risk to soil and groundwater, since ashes are usually stored in uncovered fields on power plants vicinity.