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The adoption of sustainable technologies that optimize biological nitrogen fixation (BNF) by peanut crops is essential to improve plant growth and ensure high grain yield potential. A study was conducted to investigate the efficiency of inoculation with Bradyrhizobium spp. and foliar application of molybdenum (Mo) in improving the productive response of peanut crop (Arachis hypogaea L., cv. IAC Tatu ST) in moderately acidic sandy soil (pH 5.0) of the Cerrado region, Brazil during two growing seasons (2016/2017 and 2017/2018). Treatments consisted of uninoculated seeds (control) and inoculated with Bradyrhizobium spp. and foliar application of Mo at five rates (0, 25, 50, 100, and 150 g Mo ha−1). These treatments were arranged in a randomized block design in split plots with four replicates. Nodulation, shoot dry matter, leaf N concentration, and peanut grain yield were significantly high in plants inoculated with Bradyrhizobium spp. in both growing seasons. The grain yield increased by 13% and 12% with the inoculation of Bradyrhizobium spp. compared with non-inoculated plants in the 2016/2017 and 2017/2018 seasons, respectively. Plants fertilized with Mo showed higher root nodulation, leaf N concentration, and shoot dry matter production than control plants in both growing seasons. However, the crop grain yield was significantly high (24%) only in the 2016/2017 season in plants fertilized with Mo. The optimal rate of foliar Mo application in peanut plants cultivated in sandy soils varies from 80 to 100 g of Mo ha−1. Due to improved root nodulation, N uptake, plant growth, and higher crop grain yield, rhizobium inoculation and foliar application of Mo are sustainable agricultural practices that should be recommended for peanut growers. [ABSTRACT FROM AUTHOR]

Theaim of this cross-sectional study was to compare workplace conditions and metal exposures in 431 waste pickers who worked nearby at the Estrutural Dump in Brasilia utilizing hair (n = 310) and nail (n = 355) as matrices of exposure. Waste pickers were grouped according to their workplace (open waste dump: G1 and sorting plants: G2). Hair and nail samples were collected and analyzed using ICP-MS. The work duration in the facilities was significantly different between the groups with averages of 16.46 (8.48) yrs and 9.26 (6.28) yrs for hair donors in G1 and G2, and 15.92 (7.72) yrs and 8.55 (5.77) yrs for toenail donors in G1 and G2, respectively. The arithmetic means (µg/g) of cadmium, copper, lead, and manganese in hair were significantly higher in G2 (0.076 ± 0.133; 19.61 ± 18.16; 2.27 ± .56 and 3.87 ± 5.59, respectively) compared to G1 (0.069 ± 0.235; 15.72 ± 15.18; 1.72 ± 4.04 and 3.65 ± 5.5, respectively). Concentrations of arsenic, barium, cadmium, copper, cobalt, lead, manganese, and molybdenum in nail were significantly higher in G2 (0.57 ± 0.39; 22.74 ± 42.06; 0.1 ± 0.08; 22.7 ± 51.60; 0.48 ± 0.45; 4.69 ± 9.43; 19.07 ± 20.75; 1.80 ± 1.76, respectively) compared to G1 (0.40 ± 0.28; 15.32 ± 22.31; 0.08 ± 0.11; 11.91 ± 16.25; 0.37 ± 0.37; 3.94 ± 15.04; 13.01 ± 19.08; 1.16 ± 1.80, respective. Our findings suggest that the studied population was exposed to toxic metals and indicates the need for chemical exposure prevention policies to monitor chemical risk exposures in waste pickers. [ABSTRACT FROM AUTHOR]

This work aimed to evaluate the use of phosphorus (P) fertilizer, rhizobia inoculation, and seed enrichment with molybdenum (Mo) as tools for enhancing the cowpea yield in the Brazilian eastern Amazon. A set of field and greenhouse experiments were carried out in cerrado and upland forest environments. Four levels of P fertilization, eight rhizobia strains, and the application of mineral nitrogen (N) were evaluated for the cultivar BRS Tumucumaque (BR = Brasil e S = Sementes), and two levels of Mo seed enrichment were assessed for the cultivars BRS Tumucumaque and BRS Guariba. Grain yield increased linearly with the level of P applied. Inoculation with the rhizobia strain BR 3267 increased the shoot and nodule mass of the cultivar BRS Tumucumaque. There was no difference in grain yield and grain N accumulation between inoculation with seven rhizobia strains, N mineral fertilization and the control (without inoculation and N fertilization) in cerrado and upland forest environments. Cowpea grain yield and grain N accumulation were higher in the cerrado than in the upland forest environment and when the seeds were enriched with Mo. Phosphorus fertilization and seed enrichment with Mo are efficient tools to enhance cowpea yield in the Brazilian Amazon. [ABSTRACT FROM AUTHOR]

The importance of environmental quality for global social and ecological development, including soil degradation, cannot be overstated. Trace elements dispersed in the environment due to anthropogenic or geogenic activities can result in ecotoxicological impacts, negatively influencing environmental quality. The reference values for soil quality concerning trace elements are primarily based on geological, geomorphological, and pedological patterns. However, intrinsic geological factors may diverge some concentration levels from established norms. Therefore, conducting comprehensive surveys of environmental quality reference values becomes imperative, incorporating geological, geomorphological, and pedological patterns. A deeper understanding of the distribution of these elements is also required. Multivariate analysis proves crucial in compartmentalizing the most relevant factors, particularly in regions marked by bimodal magmatism arising from post-collisional distensional processes, such as the Santa Angélica intrusive suite in southeast Brazil. This study collected soil samples from pastures and natural grasslands with minimal anthropogenic intervention at two depths. These samples underwent various chemical and physical analyses. Statistical techniques such as correlation analysis, principal component analysis, hierarchical clustering, and geostatistics were utilized to interpret the data. The analysis revealed a correlation between the clay fraction and trace elements, demonstrating that clustering is an effective methodology for ascertaining landscape distribution patterns of these components. When compared to quality reference values, it was observed that most soil content levels exceeded both global and local standards. This study suggests that the presence of barium (Ba) in the soil might be due to the isomorphic replacement of feldspathic minerals in acidic and intermediate rocks, whereas molybdenum (Mo) seems to be associated with soils in the domain of porphyritic allanite granite. However, additional research is warranted to determine the concentration factor of Mo in this scenario accurately. [ABSTRACT FROM AUTHOR]

This study evaluated physical characteristics, chemical composition, content of vitamin C, vitamin E, carotenoids, and minerals in biribiri fruits (Averrhoa bilimbi) from the Middle Doce River region (Minas Gerais, Brazil). Titratable acidity was determined by volumetric neutralization, pH by direct potentiometry, soluble solids by refractometry, humidity by gravimetry, ash by calcination in muffle, proteins by the micro-Kjeldahl method, dietary fiber by non-enzymatic gravimetric method and lipids using a Soxhlet extractor. Carotenoids and vitamin C were analyzed by high-performance liquid chromatography (HPLC) and vitamin E by HPLC with fluorescence detector. Fourteen minerals were analyzed by inductively coupled plasma atomic emission spectrometry. Biribiri showed high yield of edible portion (100%), low lipid, protein and carbohydrate content, and; consequently, low total energy value (25.36 kcal 100 g-1). The fruit also showed low dietary fiber content (0.62 g 100 g-1), total vitamin E (17.62 µg 100 g-1), total carotenoids (0.32 g 100 g-1), and high vitamin C, zinc, copper, iron content, manganese, molybdenum and chrome content. Regarding the heavy metals, the fruit showed no cadmium, and traces of aluminum and nickel. In conclusion, biribiri presented low energy value and expressive contents of dietary fibers, vitamin C, iron, manganese, molybdenum, chromium, zinc, and copper. [ABSTRACT FROM AUTHOR]

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The possible benefits of molybdenum (Mo)-enriched seeds for grain legumes have yet to be addressed in sub-humid tropical areas, where cowpea (Vigna unguiculata L.) is an important crop. In 2016, seeds with 0.014 (low), 0.674, or 1.987 (high) µg seed-1 of Mo were harvested from plants sprayed with 0, 250, or 850 g ha-1 of Mo, respectively. These seeds were combined with either Bradyrhizobium inoculation (with or without) in 2017 or nitrogen (0 or 60 kg ha-1) in 2018 and evaluated under small farmer management in Maranhão State, Brazil. Maximum nodules plant-1 in these trials was 5.2. In 2017, inoculation acted synergistically with Mo-enriched seeds by increasing nodule weight. Averaged across inoculation levels, plants originated from high-Mo seeds had 36% higher leaf N concentration than those raised from low-Mo seeds. Inoculation did not affect yield, but plants grown from high-Mo seeds yielded 42% more than those raised from low-Mo seeds. In 2018, seed Mo content did not affect nodule and yield where urea was applied. However, without urea, plants raised from high-Mo seeds had 3.5-fold greater values for nodule number and weight and yielded 70% more than those grown from low-Mo seeds. We conclude that using Mo-enriched seeds associated with Bradyrhizobium inoculation would improve cowpea N nutrition and yield in a sustainable way. [ABSTRACT FROM AUTHOR]

High rates of biological nitrogen fixation (BNF) are commonly reported for tropical forests, but most studies have been conducted in regions that receive substantial inputs of molybdenum (Mo) from atmospheric dust and sea‐salt aerosols. Even in these regions, the low availability of Mo can constrain free‐living BNF catalyzed by heterotrophic bacteria and archaea. We hypothesized that in regions where atmospheric inputs of Mo are low and soils are highly weathered, such as the southeastern Amazon, Mo would constrain BNF. We also hypothesized that the high soil acidity, characteristic of the Amazon Basin, would further constrain Mo availability and therefore soil BNF. We conducted two field experiments across the wet and dry seasons, adding Mo, phosphorus (P), and lime alone and in combination to the forest floor in the southeastern Amazon. We sampled soils and litter immediately, and then weeks and months after the applications, and measured Mo and P availability through resin extractions and BNF with the acetylene reduction assay. The experimental additions of Mo and P increased their availability and the lime increased soil pH. While the combination of Mo and P increased BNF at some time points, BNF rates did not increase strongly or consistently across the study as a whole, suggesting that Mo, P, and soil pH are not the dominant controls over BNF. In a separate short‐term laboratory experiment, BNF did not respond strongly to Mo and P even when labile carbon was added. We postulate that high nitrogen (N) availability in this area of the Amazon, as indicated by the stoichiometry of soils and vegetation and the high nitrate soil stocks, likely suppresses BNF at this site. These patterns may also extend across highly weathered soils with high N availability in other topographically stable regions of the tropics. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyze the effects of molybdenum and inoculant application via seed treatment in soybean, and their role in the nitrate reductase enzyme activity, agronomic traits and physiological quality of the produced seeds. The experiment was conducted at the Federal University of Pelotas (UFPel), Rio Grande do Sul state, Brazil. The treatments were shaped by five doses of molybdenum (zero; 16; 32; 48; 64 g.100kg-1 of seeds) combined with the presence and absence of liquid inoculant (Bradyrhizobium japonicum), at a dose of 200 mL per 100 kg of seeds. The evaluations of nitrate reductase activity, agronomic traits and physiological seed quality were performed in the present work. The measured agronomic traits were: plant height, number of pods per plant, number of seed per plant and thousand-seed weight. Standard germination test was executed to evaluate the produced seed viability. First germination counting, accelerated aging test, cold test, plantlet shoot and root length, plantlet shoot and root dry mass, and field seedling emergence were utilized to measure the seed vigour. Molybdenum, both in presence and absence of inoculant, positively influenced the enzymatic activity, for both vegetative and reproductive stages. The addition of inoculant and molybdenum provided increase in the vigour of the produced seeds. The enzyme activity was positively correlated with the agronomic traits and vigour tests. The addition of inoculant and molybdenum in the seed treatment provides a better expression of nitrate reductase activity and vigour of the produced seeds. [ABSTRACT FROM AUTHOR]

This work aimed to perform the characterization of electrical properties of niobium pentoxide, Nb2O5, pure and doped with molybdenum, prepared by powder metallurgy route and to do a comparative analysis of the influence of this material when sintered in a muffle or in a microwave oven. The results showed that the doping of the niobium pentoxide with 0.5% or 1% of molybdenum along with the process of sintering in a microwave oven make the material more applicable as a microwave absorber material for electromagnetic radiation in the UHF (ultra-high frequency) range between 0.3 to 3 GHz. The motivation of this work was associated with the fact that in Brazil are located two of the largest niobium reserves in the world. Under this view, the study of the processing of the ceramic materials is important considering possible technological applications. [ABSTRACT FROM AUTHOR]

The levels of potassium (K), calcium (Ca), sodium (Na), magnesium (Mg), Zinc (Zn), iron (Fe), copper (Cu), molybdenum (Mo), manganese (Mn), and lead (Pb) were determined in Nigerian and Brazilian milk samples. Their concentrations in powdered milk were in the order K > Ca > Na > Mg > Zn > Fe > Cu > Mo > Mn > Pb, and for liquid milk, K > Ca > Mg > Zn > Fe > Mo > Cu. The margin of exposure and provisional tolerable weekly intake values of Pb in powdered milk indicated no significant health risks to consumers. The rank order of microelements in powdered milk consumers based on target hazard quotient (THQ) was Zn > Mo > Cu > Pb > Fe > Mn, and for liquid milk, Zn > Mo > Cu > Fe. The THQs of microelements in milk for the Nigerians and Brazilians were lower than 1. Carcinogenic risk (CR) of Pb in children and adults was close to 1 E-6 but lower than 1 E-5, indicating inconsiderable non-carcinogenic and carcinogenic risks. The presence of Pb in powdered milk is of great concern, therefore, food quality and safety plans must be carried out during production. • Powder milk contributed more to the RDA of mineral elements than liquid milk. • MOE and PTWI showed that Pb in powder milk does not pose a significant health risk. • THQ and CR values indicated inconsiderable noncarcinogenic and carcinogenic risks. • Children are more susceptible to noncarcinogenic and carcinogenic risks than adults. [ABSTRACT FROM AUTHOR]

Abstract: Sowing seeds with high concentrations of P or Mo can improve growth and nodulation of common bean (Phaseolus vulgaris) plants. However, the performance of the bean crop originating from seeds enriched with P and Mo has not yet been assessed under field conditions. This study aimed to evaluate the effect of sowing seeds enriched with P and Mo, harvested from plants that received foliar sprayings of P or Mo or both, on growth and yield of common bean crop. Seeds with contrasting concentrations of P and Mo were sown in three field experiments in Brazil (in 2006 and 2008 in Rio de Janeiro State, and in 2009 in Goiás State) with different N sources (control without N, seed with rhizobia inoculation, rhizobia inoculation plus 40kgNha−1 side-dressed, mineral N with 60kgNha−1). In 2006, seeds enriched with P and Mo increased nodule mass at 32 days after emergence (DAE), shoot N and biomass at 48 DAE, and grain yield and N content, for most combinations of the three cultivars and N sources evaluated. In 2008, the highest shoot growth at 57 DAE and grain yield were obtained with low-P high-Mo seeds, which was partially due to the higher Mo concentration of these seeds. In 2009, seeds enriched with P and Mo increased nodule mass at 34 DAE and grain yield but only for plants receiving inoculation plus side-dressed N. The results demonstrate the benefits of seeds with high concentrations of P and Mo for improving bean yield, although such yield increases were more effective for plants inoculated with rhizobia than amended with N. Sowing enriched seeds, associated with rhizobia inoculation and side-dressed N, provided grain yields much higher than the average common bean yields in Brazil. [Copyright &y& Elsevier]

Molybdenum (Mo) reserve in large seeds can complement Mo uptake by plants from soil, but the content of Mo in common bean (Phaseolus vulgaris L.) seed for this purpose is unknown. We hypothesized that 3.639 ± 0.751 μg Mo seed-1 would be sufficient to complement Mo uptake by irrigated common bean plants from a Mo-poor soil. Three field experiments were performed in a clayey Ultisol naturally infested by native strains of Rhizobium in Zona da Mata, Minas Gerais, Brazil. Treatments were arranged as 4 × 2 factorial combination of Mo contents in seeds [small (0.007 ± 0.007 or 0.248 ± 0.057 μg Mo seed-1) or large (3.639 ± 0.751 or 6.961 ± 1.844 μg Mo seed-1)] and Mo spraying treatments (90 g ha-1 or unsprayed) with six replications. Phosphorus, N (25 kg ha-1), and K were applied together in the furrow during planting time. No topdressing N was applied. Final plant population and seed yield were evaluated in two experiments. Molybdenum contents in the seeds did not affect plant population. On average, unsprayed plants from seeds with small Mo contents yielded 1785 kg ha-1, while those from seeds with large Mo content yielded 2109 kg ha-1. Foliar application of Mo increased plant N status, plant growth, and yield in plants originated from seeds with small Mo content, but not in plants grown from seeds with large Mo content. We conclude that 3.639 ± 0.751 μg Mo seed-1 sufficiently complement the Mo uptake by common bean plants from soil. [ABSTRACT FROM AUTHOR]

Abstract: High soybean yields require large amounts of nitrogen (N), which can be obtained mainly from symbiotic N2 fixation. However, the efficiency of this biological process can be limited by micronutrient deficiencies, especially of molybdenum (Mo). In Brazil, soybean generally responds positively to fertilization with Mo in soils of low fertility and in fertile soils depleted of Mo due to long-term cropping. The micronutrient can be supplied by seed treatment, however toxicity of Mo sources to Bradyrhizobium strains applied to seed as inoculant has been observed, resulting in bacterial death and reductions in nodulation, N2 fixation and grain yield. Therefore, use of seeds enriched in Mo could be a viable alternative to exterior seed treatment, allowing elite inoculant strains of Bradyrhizobium to sustain high rates of biological N2 fixation. We demonstrated the feasibility of producing Mo-rich seeds of several soybean cultivars, by means of two foliar sprays of 400gMoha−1 each, between the R3 and R5 stages, with a minimum interval of 10 days between sprays. As a result of this method, considerable increases in seed-Mo content were obtained, of as much as 3000%, in comparison to seeds obtained from plants which received no Mo. In field experiments performed in soils with low N content and without any N-fertilizer supply, inoculation of Mo-rich seeds produced plants with increased N and Mo contents in the grain and higher yields of total N and of grain. In most cases, Mo-rich soybean seeds did not require any further application of Mo-fertilizer. [Copyright &y& Elsevier]

In crops of the sugarcane, the concentrations of molybdenum (Mo) in the leaves are generally lower than 0.3 mg Mo kg-1. These low concentrations have resulted in limitations in the methods and instruments that can be used for these analyses. The objective of this study was to evaluate three different techniques to determine the concentration of Mo in sugarcane leaves sampled in the principal sugarcane-producing areas in Brazil. Two spectrometric techniques were evaluated by using ICP-EAS (Inductively Coupled Plasma-Emission Automated System) and DCP-MEAS (Direct Coupled Plasma-Multiple Emission Automated System) and a colorimetric technique of the reaction between potassium iodide and hydrogen peroxide (KI-H2O2). The techniques ICP-EAS and KI-H2O2 produced results of satisfactory accuracy and precision, whereas the DCP-MEAS consistently overestimated the Mo concentrations in cane leaves. The KI-H2O2 technique showed sensitivity 5 times greater than the ICP-EAS, with minimum detection limits of 0.1 and 0.5 mg Mo kg-1, respectively. [ABSTRACT FROM AUTHOR]

Environmental contamination has been a cause of concern worldwide, being aggravated by anthropogenic activities carried out without the correct disposal of toxic products in the various habitats on our planet. In Brazil, mining companies are responsible for the contamination of large river basins with toxic elements from mining activities. Among these elements, arsenic draws attention because it is highly carcinogenic and found in waters in concentrations above those recommended by regulatory agencies. Here, Fe 2 (MoO 4 ) 3 nanoparticles are synthesized and used as a filter medium in water purification systems contaminated with arsenic. The adsorption kinetics of arsenic by Fe 2 (MoO 4 ) 3 nanoparticles is fast, showing pseudo-second-order rate constants of 0.0044, 0.0080, and 0.0106 g mg -1  min -1 for As 3+ , As 5+ , and MMA, respectively. The adsorption isotherms are better adjusted with the Langmuir and Redlich-Peterson models, indicating that the arsenic adsorption occurs in monolayers on the Fe 2 (MoO 4 ) 3 surface. The Fe 2 (MoO 4 ) 3 adsorption capacities determined for the As 3+ , As 5+ , and MMA species are 16.1, 23.1, and 23.5 mg g -1 , respectively. The Fe 2 (MoO 4 ) 3 filter is efficient in purifying arsenic-contaminated water, reducing its initial concentration from 1000 μg L -1 to levels close to zero. Biological tests indicate that Fe 2 (MoO 4 ) 3 nanoparticles and filtered water have no cytotoxic, genotoxic, and mutagenic risks to human life. Those results suggest that the Fe 2 (MoO 4 ) 3 filter can be used as an efficient and safe technology for the purification of water contaminated by arsenic.