Total Mn Research Articles

MAXIMIZE UTILIZATION OF SOME ORGANIC FERTILIZERS TO PRODUCE THE HIGHEST YIELD OF COWPEA.

Two field experiments were established in middle Nile delta alluvial soils. The study was conducted on the two successive summer seasons of 2016 and 2017 in the experimental farm of Tag El-Ezz Agricultural research station, Agricultural research center (ARC), Dakahlia governorate, Egypt. The experiment was laid out in a split plot design with three replications, assigning nine treatments to study the effect of three forms of organic fertilization (without, farmyard manure and compost rice straw) as main plot, and 3 forms of foliar application (control, mix of micro nutrients (Fe, Zn and Mn) and humic acid (HA)) as sub plot on growth, yield and chemical constituents of cowpea (Vigna unguiculata L.). The obtained results showed that, addition of organic amendments in forms of compost rice straw significantly increased plant growth parameters (plant height, fresh weight, dry weight and number of leaves), chemical composition of leaves (chlorophyll a, b and total chlorophyll content, N, P, K, Fe, Zn and Mn as well as quality parameters (C. protein, T. carbohydrates, C. fiber, ash and total sugar of cowpea seeds except with moisture conetnt) and yield as well as its components (No. of pods/plant, No. of seed/pod, 100 seed weight and seed yield, also availability of soil (N, P and K). On the other hand; mix of micro elements gave significant positive effect and higher average values for all parameters previously. The interaction effect between organic fertilization and foliar application show a primitive effect on all parameters and the highest mean values of parameters was recorded with using CRS as organic fertilization and mix of micro nutrients as foliar application.

Impact of Fe3O4 nanoparticle on nutrient accumulation in common bean plants grown in soil

The effect of Fe3O4 nanoparticles (NPs) on chemical properties of the soil rhizosphere and on the accumulation of nutrients in common bean plants was studied for two different concentrations of Fe3O4 NPs. The root-to-leaves translocation index for micro- and macronutrients was calculated. The results showed that Fe3O4 NP treatments had a significant effect ( $$P < 0.05$$ ) on the chemical properties of soil rhizosphere in terms of an increase in the contents of total P, extractable P, total K, extractable K, Ca, total Mn, total Fe and cation exchange capacity and of a decrease in Cl content in soil. The treatments led to a marked increase in the accumulation of nutrients in plants by revealing a higher content of total P, K, Ca, Mn and Fe in roots, stems and leaves. In addition, the plants treated with Fe3O4 NPs showed lower translocation of total Mn and Fe to stems and leaves compared with the control plants. The results indicate that Fe3O4 NPs may contribute to the conversion of the insoluble forms of total P, extractable P, total K, extractable K, Ca, total Mn and total Fe in soil into soluble forms that can dissolve in the soil solution and be taken up by plants. A greater capability in the roots, stems and leaves of Fe3O4-NP-treated plants to take up the nutrients suggests a beneficial effect for plant development and health. Likewise, the roots of plants treated with Fe3O4 NPs absorbed and accumulated the greatest quantities of Mn and Fe compared with the control plants.

Risk assessment due to dermal exposure of trace elements and indigo dye in jeans: Migration to artificial sweat

The concentration of a number of trace elements (Ag, Al, As, B, Ba, Be, Bi, Cd, Cr, Co, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sb, Sc, Se, Sm, Sr, Sn, Tl, Ti, V and Zn) were determined in 42 commercialized denim garments (jeans and shirts), being dermal exposure subsequently assessed. Migration experiments with artificial acid and basic sweat were also conducted to determine the release of these elements, as well as indigo dye. In a similar way than for the total content, Mg (124 and 99.4 µg/g) and Mn (27.1 and 7.20 µg/g) showed the highest concentrations in both artificial sweat, acid and basic, respectively. Indigo dye migrated at levels ranged from 3.22 to 7.76 mg/g, being higher in dark than in light blue fabrics. The levels of trace elements and indigo were analysed according to materials of fabric, colour, brand, and eco-labelling. Using total content and migrations rates, dermal exposure to trace elements for adult men, women and teenagers were calculated under the two sweat extractions. Non-carcinogenic and carcinogenic risks due to dermal exposure to the elements here analysed in cloths were assessed. Both risks were in the limits of safe to according to international regulations. However, the maximum exposure to Sb reached a hazard quotient (HQ) of 0.3 in clothes partially made of polyester. Despite some authors have established that indigo is an agonist of the aril receptor, health risks due to exposure to indigo dye were not calculated due the lack of toxicological data.

Spatial Patterns of Potentially Hazardous Metals in Soils of Lin'an City, Southeastern China.

Urban soils are strongly related to human health. In this study, Lin’an city was chosen as a typical small-scale city with which to study the spatial variation of potentially hazardous metals (PHMs) in urban soils and their potential ecological risks using multivariate analysis, geostatistics and GIS techniques. A total of 62 soil samples were collected from the study area. The results showed that the average concentrations of total soil Mn, Cu, Zn, Pb, Cr, Cd were 439.42, 42.23, 196.80, 62.55, 63.65, 0.22 mg·kg−1, respectively. Compared with the background values and the environmental quality standards, these PHMs were accumulated in urban soils to some extent. The single potential ecological risk indices of PHMs indicated that Pb and Cd had relatively high ecological risks. The pH and most of the PHMs had significant correlations (p < 0.05). The principle components analysis (PCA) showed that Pb, Zn and Cu had similar pollution sources related to the vehicles’ exhaust emission; Mn and Cr were mainly from the parent materials; while Cd was from the emission of industrial manufactories. The spatial structures and distributions of PHMs and their corresponding available fractions had strong/moderate spatial autocorrelation, which were influenced by human activities.

滇南喀斯特地区灌木群落和人工林土壤元素化学计量特征

PDF HTML阅读 XML下载 导出引用 引用提醒 滇南喀斯特地区灌木群落和人工林土壤元素化学计量特征 DOI: 10.5846/stxb201810072159 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划（2016YFC0502501） Characteristics of soil stoichiometry in native shrub and plantation communities in karst regions of Yunnan province Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:在云南喀斯特地区，为提升退化灌木群落的生态系统服务功能，营造了不同树种的人工林分。这些人工林分如何影响土壤化学性质还未得到充分认识。以云南泸西县灌木群落及三种常见人工林（云南松（Pinus yunnanensis）、赤杨（Alnus japonica）和侧柏（Platycladus orientalis））土壤为研究对象探讨喀斯特地区在人工林建造后土壤的13种元素全量、可利用性含量和化学计量学特征变异格局，为喀斯特石漠化治理提供理论依据。结果表明，1）基于判别分析，四种群落土壤化学计量特征可以显著区分。土壤Fe、P、K、Mn全量及交换性Ca、交换性Mg和NH4+-N对区分四种群落土壤贡献最大。2）四种群落之间相比，侧柏林土壤C、N、S、Na全量和NO3--N含量均低于其他三种群落，土壤肥力较低；赤杨林铵态氮含量最高；云南松林有效Fe、有效Cu含量最高。而且，四个群落土壤全量C/N、C/K比值存在显著差异性。3）根据四种群落13种土壤元素和pH值相关性分析，35对元素具有显著相关性，占所有元素对数的38.5%，说明该地土壤元素积累的相互依赖性。与灌木群落相比，人工林土壤元素全量和可利用性含量相关性比例均更高。这些研究结果对今后基于适地适树人工林营造、生态系统服务功能提升和经营利用，均具有重要指导意义。 Abstract:The natural forest vegetation degraded to shrub-dominated plant communities in karst areas of Yunnan province, due to the geological conditions and long-term human disturbance. Plantation stands of different tree species have been established to raise ecosystem services across Yunnan province, such the karst shrub areas, during the last three decades. In this context, the elemental compositions of original soils could be influenced to a certain extent. In this study, we measured the total and available element concentrations of 13 elements (C, N, S, P, K, Ca, Mg, Na, Fe, Al, Cu, Zn, and Mn), and summarised the stoichiometric traits of soils in the shrub, Pinus yunnanensis, Alnus japonica, and Platycladus orientalis stands in Luxi county, Yunnan province. The results showed that firstly, soil stoichiometric traits of four communities were significantly distinguished based on canonical discriminant analysis. Furthermore, soil total Fe, P, K, Mn concentrations, and available Ca, Mg, and NH4+-N concentrations, contributed to the differences the most. Secondly, cypress stands showed lower total C, N, S, Na and NO3--N concentrations compared with the other three communities, suggesting that the soil fertility was reduced. The soil NH4+-N concentration was higher in alder stands compared with the other communities; the soil available Fe and Cu concentrations were highest in the Yunnan pine stand. Furthermore, there were also significant differences of C/N and C/K ratios among the four stands. Thirdly, based on a correlation analysis of the 13 elements and the pH value, 35 pair-elements showed a significant correlation, accounting for 38.5% of all elements, suggesting that there was strong inter-dependence accumulation of soil elements in these karst areas. Compared with the shrub community, the significant correlations between the total elements and available elements in plantation stands were higher. Our results have important implications for plantation establishment and management to increase ecosystem services in such karst areas. 参考文献 相似文献 引证文献

Mineralization of organics in hazardous waste sulfuric acid by natural manganese oxide ore and a combined MnO2/activated carbon treatment to produce qualified manganese sulfate.

To effectively dispose and utilize the hazardous waste H2SO4 generated from alkylation, an environmentally friendly and feasible technology for the simultaneous oxidative degradation of organics and consumption of H2SO4 was developed. Pyrolusite, a natural manganese oxide ore, was used for the oxidative degradation and mineralization of the organics, and reduction leaching of Mn from the pyrolusite occurred simultaneously. The total organic carbon (TOC) removal and Mn leaching efficiency were 46% and 16.44%, respectively. In addition, pyrites was applied as a reductant to extract Mn from the pyrolusite, and an Mn leaching efficiency of 98.31% was obtained under the optimized conditions of 4/1 liquid/solid ratio, 350 rpm stirring speed, 1.5 mol L-1 H2SO4 concentration, and 95 °C for 1 h in the first oxidative degradation stage and a molar ratio of FeS2/MnO2 of 0.55/1 for 4 h in the reduction leaching stage. Subsequently, a combined treatment of MnO2/activated carbon was developed for further oxidation and adsorption of the organics in the solution, with the TOC removal of 84.11%. The resulting purified MnSO4 solution was concentrated to produce qualified MnSO4∙H2O, which met the requirements of an industrial product. This technology showed application potential in highly-efficient removal of hazardous organic contaminates.

In vitro bioaccessibility of metals sourced of tape tea

An in vitro bioaccessibility of metals was considered in this study to evaluate the toxicity of tape tea, a low cost drug. Taking into account total element determination, Co, Ni, Mn, Fe and Zn were found at higher concentrations, compared to other metals, and, then, their bioaccessibility was evaluated, employing the UBM protocol. According to our results, Mn, Ni, Zn and Co are fully presented in the bioaccessible fraction, whereas Fe was observed only 50% bioaccessible.

Dynamics of Fe, Mn, and Al Liberated from Contaminated Soil by Low-Molecular-Weight Organic Acids and Their Effects on the Release of Soil-Borne Trace Elements

A 15-day batch experiment was conducted to investigate the behaviours of Fe, Mn, and Al oxides upon attack by three common low-molecular-weight organic acids, and their effects on liberation of trace elements from a multi-contaminated soil. While the capacity of malic acid to mobilize soil-borne Fe, Mn, and Al was weaker compared to citric and oxalic acids, a similar trend was observed, showing that the concentration of dissolved Fe, Mn, and Al increased with increasing duration of the experiment. Marked increase in metal concentrations only took place after 5 or 7 days of the experiment. For the same organic acid treatment, Fe, Mn, and Al all showed a very similar temporal variation pattern. The concentration of dissolved Fe, Mn, and Al was markedly controlled by the total Fe, Mn, and Al contained in the soil, respectively. It appears that manganese oxides were more reactive to the organic acids, as compared to their Fe and Al counterparts. However, when multiple organic acids were present, the soil-borne Fe, Mn, and Al were mobilized rapidly within the first 5 or 7 days of the experiment and then tended to decrease. The formation of insoluble Fe, Mn, and Al organic complexes tended to be enhanced due to co-existence of multiple organic acids, resulting in the re-immobilization of the dissolved Fe, Mn, and Al. The organic acid-driven dissolution of Fe, Mn, or Al had a major control on the mobilization of As, Cr, Zn, Ni, Cu, and Cd that were bound to these oxides with a correlation coefficient being frequently greater than 0.9 for As, Cr, Zn, and Ni.

REDUCTIVE LEACHING OF LOW GRADE MANGANESE ORE (LGMO) USING GLUCOSE IN SULPHURIC ACID: OPTIMIZATION CONDITION USING RESPONSE SURFACE METHODOLOGY

Manganese (Mn) is an important metal in producing a good quality steel, that the total Mn consumption in this industry reaches 85 to 90%. Despite of this huge demand, Mn faces a shortage supply due to depletion of high grade Mn ore. As an alternative, low grade manganese ore (LGMO) can be utilized to fulfill the industry demand. The aim of this work is to determine the optimum condition of the reductive leaching process of LGMO using Response Surface Methodology (RSM). The design of experiment (DOE) was made using RSM by Central Composite Design (CCD) with 22 and 3 central points. In this work, the effect of variables such as sulphuric acid concentration (X1) and weight of glucose (X2) were examined. The experimental data obtained from Analysis of Variance (ANOVA) were analyzed. Subsequently, the most significant variable was identified and fitted into a quadratic model. It is found that the interaction between sulphuric acid concentration and amount of glucose (X1X2) is the most important factor in manganese (Mn) extraction. The optimum leaching condition is obtained at 2.5 M sulphuric acid concentration and 2 g weight of glucose at 60 minutes leaching time. Within this experimental condition, a high level of Mn extraction ratio at 88.97% is achieved.

Impact of natural re-oxygenation on the sediment dynamics of manganese, iron and phosphorus in a euxinic Baltic Sea basin

The Baltic Sea is characterized by the largest area of hypoxic (oxygen (O2) < 2 mg L−1) bottom waters in the world’s ocean induced by human activities. Natural ventilation of these O2-depleted waters largely depends on episodic Major Baltic Inflows from the adjacent North Sea. In 2014 and 2015, two such inflows led to a strong rise in O2 and decline in phosphate (HPO42−) in waters below 125 m depth in the Eastern Gotland Basin. This provided the opportunity to assess the impact of such re-oxygenation events on the cycles of manganese (Mn), iron (Fe) and phosphorus (P) in the sediment for the first time. We demonstrate that the re-oxygenation induced the activity of sulphur (S)-oxidising bacteria, known as Beggiatoaceae in the surface sediment where a thin oxic and suboxic layer developed. At the two deepest sites, strong enrichments of total Mn and to a lesser extent Fe oxides and P were observed in this surface layer. A combination of sequential sediment extractions and synchrotron-based X-ray spectroscopy revealed evidence for the abundant presence of P-bearing rhodochrosite and Mn(II) phosphates. In contrast to what is typically assumed, the formation of Fe oxides in the surface sediment was limited. We attribute this lack of Fe oxide formation to the high flux of reductants, such as sulphide, from deeper sediments which allows Fe(II) in the form of FeS to be preserved and restricts the penetration of O2 into the sediment. We estimate that enhanced P sequestration in surface sediments accounts for only ∼5% of water column HPO42− removal in the Eastern Gotland Basin linked to the recent inflows. The remaining HPO42− was transported to adjacent areas in the Baltic Sea. Our results highlight that the benthic O2 demand arising from the accumulation of organic-rich sediments over several decades, the legacy of hypoxia, has major implications for the biogeochemical response of euxinic basins to re-oxygenation. In particular, P sequestration in the sediment in association with Fe oxides is limited. This implies that artificial ventilation projects that aim at removing water column HPO42− and thereby improving water quality in the Baltic Sea will likely not have the desired effect.

Distribution of desferrioxamine-B-extractable soluble manganese(III) and particulate MnO2 in the St. Lawrence Estuary, Canada

Soluble organically-complexed manganese(III) (Mn(III)-L) is an intermediate species in the manganese cycle. The reactivity of the complex(es) depends on the abundance and nature of the ligand(s), as well as its physicochemical environment. Currently, the strength of Mn(III)-L complexes is assessed by their ability to react either directly with a porphyrin complex, using the kinetics of its competitive ligand exchange reactions, or after being reduced to manganese(II). We present a new three-step technique that quantifies part of the Mn(III)-L pool which may represent a bioavailable and reactive fraction of the complexes. This technique relies on 1) ligand exchange of the dissolved complexes in a filtered field sample with the siderophore desferrioxamine-B (DFOB), 2) chromatographic separation and concentration of manganese(III)-DFOB from the aqueous matrix, and 3) quantification of the naturally ligated manganese(III) that was outcompeted by DFOB (Mn(III)-LDFOB) at low concentrations by flow injection UV-Vis spectrophotometry. The formation of an extractable Mn(III)-LDFOB complex provides an operationally-defined benchmark by which to assess biological interactions and better understand the cycling of manganese(III) in the environment. The technique, with a detection limit of 0.09 nM, was applied to water samples collected in the St. Lawrence Estuary (SLE) and adjacent Saguenay Fjord in Canada. Mn(III)-LDFOB was ubiquitous at our study sites, but its concentration was low relative to total dissolved manganese (dMnT) and particulate MnO2. Spatial variations of the dMnT speciation within the Saguenay Fjord suggest that Mn(III)-L forms from the reduction of MnO2. Likewise, variations of the dMnT speciation along a dissolved oxygen gradient in the SLE leads us to believe that Mn(III)-LDFOB likely represents a fraction of the total Mn(III)-L that cycles more readily in estuarine and marine systems.

Significance of manganese fertilization in wheat-based cropping systems of Indo-Gangetic Plain (IGP)

Manganese (Mn) is an essential micronutrient, having critical role in plant nutrition. The Mn is component of several enzymes involved in photosynthesis and other physiological processes. The intensive cultivation of rice-wheat (RW) followed since long times, along with induction of rice in non-rice growing areas, especially in north-western Indo Gangetic Plain (NW-IGP) had led to emergence of Mn deficiency, particularly in wheat crops in RW rotation. Higher leaching losses of soil Mn under submerged rice induces Mn deficiency in the subsequent wheat crops. This paper critically assesses the literature on role of Mn on crop growth, distribution of soil Mn and its dynamics, effect of different soil characteristics on soil Mn availability under different cropping systems prevalent in IGP. Soil ionic composition, moisture status, organic matter status, soil pH, cation exchange capacity are some of the soil parameters dictating Mn dynamics in soil. Higher availability of soil Mn was reported under acidic condition, which decreasedwith increase in soil pH. Literature suggests positive effects of nitrate and phosphates on soil Mn dynamics and crop yields, whereas bicarbonate and chloride application have negative effects. Plant available Mn or DTPA-Mn varied under different cropping systems showing lower availability under RW system. Fractionation studies showed that labile pools of Mn contribute very less towards total soil Mn, leaving large proportion of soil Mn non-labile in nature, thus unavailable for plant uptake. The release of Mn from soil adsorption sites varied under different cropping systems, modifying Mn supply capacity of soil. Maximum release of Mn was found under frequently irrigated sugarcanesugarcanecropping system. Such information are essentially required for developing efficient Mn fertilization scheduling to improve the yield and quality of crops in IGPs.

Spectral and luminescence properties of manganese ions in vitreous lead metaphosphate

Optical materials doped with manganese ions have attracted interest as a red phosphor for warm white light LEDs. Lead-phosphate glasses are chosen for doping with manganese ions due to high refractive index of such material. In this study, new 50 PbO – 50 P2O5 – xMnO2 (x = 0.1, 1, 3, 5, 7, 10, 13 mol%) glasses are synthesized. To determine the optimal manganese ion concentration (to be used as the red phosphor) in those glasses, their spectral and luminescent properties are investigated. Mn2+ ions in lead-phosphate glasses have intense red luminescence in the wavelength range 620–690 nm. The Mn3+ ion to the total Mn ions ratio is found less than 0.1% based on the visible absorption spectroscopy data. Manganese ions in that glass are disposed at non-equivalent positions that results in nonexponential lifetime decay. The maximum absolute quantum yield value of Mn2+ ions is 49% in glass with 2.91 mol% MnO2.

Top-down evaluation of matrix effects uncertainty

Many measurements in chemistry are affected by matrix effects responsible for larger deviation between results from the analysis of various matrices than observed from the replicate analysis of the same matrix. The identification of cases where matrix effects are relevant is useful to know if measurement robustness to matrix effects can significantly reduce the measurement uncertainty, e.g. by performing time-consuming standard addition calibrations or additional matrix clean-up. This work presents a methodology to estimate the percentage contribution of matrix effects to the measurement uncertainty by comparing the intermediate precision estimated from the analysis of a sample with the dispersion of analyte recovery observed form the analyses of samples with different matrices. The measurement model was divide in two intervals of the studied quantity: Interval I between the limit of detection and two times the limit of quantification, where the absolute measurement uncertainty is constant, and Interval II above or equal to two times the limit of quantification where the relative measurement uncertainty is constant. The division of measurements scope in these intervals allowed the comparison of information collected at different values of the studied quantity. The developed methodology was successfully applied to the analysis of total Cr, Cu, Li, Mn and Zn using a procedure developed by OSPAR and acid extractable Ni and Pb according to the EPA3051A standard in marine sediments. Matrix effects are responsible for 7.7 to 79% of the global uncertainty. For Interval II, the relative expanded uncertainty ranged from 12% to 25% and is fit for the environmental monitoring of sediments according to the way the performance of laboratories is assessed in QUASIMEME proficiency tests. The developed measurement uncertainty models produced results compatible with reference values of one Certified Reference Material and 65 proficient test samples independent of the ones used to estimate the measurement uncertainty. The used data and performed calculations are presented in a user-friendly MS-Excel spreadsheet, available as Electronic Supplementary Material, that can be used for other determinations.

Tissue-specific element profiles in Scots pine (Pinus sylvestris L.) needles

Key messageElement profile signatures of needle tissues differentiated four tissues: epidermis (main contributor: calcium), endodermis (main contributors: magnesium, sulphur and manganese), mesophyll (main contributor: potassium), and transfusion parenchyma (main contributor: zinc).Distribution of elements in cross-sections of Scots pine (Pinus sylvestris L.) needles was investigated using micro-proton-induced X-ray emission. Tissue-specific distributions of magnesium (Mg), sulphur (S), calcium (Ca), phosphorus (P), potassium (K), chlorine (Cl), manganese (Mn), iron (Fe), zinc (Zn), aluminium (Al) and silicon (Si) were resolved in a quantitative manner. Distribution maps and tissue-specific concentrations revealed the largest concentration of Ca in epidermis, of Mg, S and Mn in endodermis, of K in mesophyll and phloem and of Zn in transfusion parenchyma. Phosphorus, Cl, Fe, Al and Si did not exhibit apparent tissue-specific distribution. Inverse allocation of P and Ca was observed, a likely mechanism to prevent their precipitation. Taking the area of tissues into account, relative element distribution calculations indicated that mesophyll contained the majority of the elements studied, except Ca, which predominated in the epidermis (79% of total Ca concentration) and Mn, which predominated in the endodermis (40% of total Mn concentration). When considering a complete element profile of a particular tissue, four clusters were differentiated, which generally supported single-element observations. The first cluster differentiated mesophyll, xylem, phloem, transfusion tracheids and Strasburger cells with predominance of K, the second cluster differentiated epidermis on the basis of Ca, the third cluster differentiated endodermis with contributions from Mg, S and Mn, and the fourth cluster differentiated transfusion parenchyma with contribution from Zn. Information on tissue-specific-element allocations will complement structural and functional knowledge of needle tissues and advance our understanding of element/nutrient transfers in Scots pine.

Uptake and Exportation of Micronutrients by Transgenic Cultivars of Maize Under No-tillage in the Brazilian Cerrado

Introducing cultivars of high productive potential with adequate agronomic management has contributed to the increase of maize yield in Brazil. This study aimed to characterize the extraction and exportation of micronutrients by modern maize hybrids grown in no-tillage system in the Cerrado region (Brazilian Savannah) with two fertilization levels. We established two crop environments with differentiated levels of soil fertilization, use of products for seed treatment and leaf fertilization, in which four transgenic hybrids were grown. For each environment, we used an experimental design of randomized blocks with four replicates. There were eleven plant samplings during the crop cycle to quantify dry mass production and Cu, Fe, Mn and Zn extraction. Micronutrient uptake is increased when a hybrid with higher potential for biomass production grows in an environment with greater supply of nutrients. Uptake persists throughout the maize cycle, including during the final stages of the reproductive phase, showing late demand for the crop. On average, after tasseling, about 39, 50, 42, and 49% of the total Cu, Fe, Mn and Zn absorption still occurs, respectively. Total uptake of Cu, Fe, Mn and Zn are, respectively, around 8, 199, 58 and 40 g to produce a tonne of grain, from which 23, 5, 8, and 42% are exported by the harvest. Micronutrient uptake and exportation rates for the studied transgenic hybrids are lower than the ones previously reported in Brazil and in works abroad.

Effect of Biochar and Chicken Manure on Soil Properties and Growth Traits of Coriander Plant Irrigated with Saline Water in Sandy Soil

A pot trial was conducted in the nursery of the Faculty of Agriculture, Mansoura University during the 2016/2017 season to study the effect of biochar and chicken manure on sandy soil properties and traits of coriander plant and the possibility of utilizing the seawater diluted (10%) in irrigation. Randomized complete plot design (RCBD) with three replicates was used in this study. The treatments were as follows: Without (Control), Chicken manure, (20 ton fed-1, i.e. 400 g pot-1) and biochar, (5 ton fed-1, i.e. 100 gpot-1). Results showed that the organic amendments [chicken manure and biochar] had highly significant effects on all the studied chemical and physical properties of sandy soil such as, total N, P, K, Fe, Zn, Mn, Ca, Mg, Na, pH, EC and bulk density. Adding biochar and chicken manure gave the best values of all the studied chemical and physical properties of sandy soil compared with control. Also, it was noticed surpassed that biochar treatment over chicken manure in some chemical traits of the soil, such as, total N, P, Na and Cl in the soil. On the other side, the chicken manure surpassed over biochar in some chemical traits of the soil, such as, K, Fe, Mn, Ca and Mg. Results indicated that the organic amendments [chicken manure and biochar] had highly significant effects on all the studied chemical, growth and yield traits of coriander plant, i.e. total N, P and K (%); total Fe, Zn and Mn contents (mgkg-1); plant fresh weight (g), plant dry weight (g), plant height (cm), leaves number per plant and chlorophyll content. Adding chicken manure and biochar gave the best values of all the studied chemical, growth and yield traits of coriander plant compared with control. In addition, it was noticed surpassed the chicken manure over biochar in improving all the studied chemical, growth and yield traits of coriander plant. Therefore, it could be recommended that adding the organic amendments (chicken manure or biochar) to improve the chemical and physical properties of sandy soil and chemical and growth traits of coriander plant irrigated with saline water (diluted seawater, 10%) in sandy soil.

Thioether‐Functionalized Corn Oil Biosorbents for the Removal of Mercury and Silver Ions from Aqueous Solutions

AbstractHeavy‐metal contamination is one of the most important environmental problems faced in the world, particularly in developing countries. Metals such as silver and mercury from drinking water, food, and air sources can accumulate in living organisms and present significant health concerns. Meanwhile, the demand for these metals in many industries continues to increase. In the present study, thioether‐functionalized corn oil (TFCO) from a photoinitiated thiol‐ene synthesis was utilized to remove Ag+ and Hg2+ ions from an aqueous solution. An aqueous solution containing AgNO3 and Hg[NO3]2 was prepared and contacted directly with TFCO. After vortex mixing for 60 s, the experiment ran for 351 min with the aqueous phase being periodically sampled for the analysis of metal ions (M n+). Results showed that 88.9% of Ag+ and 99.6% of Hg2+ ions were removed from the aqueous phase by the TFCO. Mass balances indicated that the total M n+ concentration in the oil phase was 13.890 g kg−1 under the conditions studied. TFCO exhibited higher selectivity for removing Hg2+ than for Ag+ ions. Analysis of the adsorption kinetics showed that a pseudosecond‐order model may be used to determine the rate of Ag+ ion sorption by the oil phase. The presence of the Hg2+ ions interfered with the adsorption of Ag+ ions from the aqueous solution.

Human exposure to trace elements in central Cambodia: Influence of seasonal hydrology and food-chain bioaccumulation behaviour

Exposure to mercury and other trace elements remains an important public health concern, worldwide. The present study involved a comprehensive field study to determine concentrations of fourteen trace elements (Al, As, Cr, Co, Cd, Cu, Fe, Hg, Mn, Ni, Pb, Se, V and Zn) in surface water and different fish species from Tonlé Sap Lake in central Cambodia, during both the dry and wet seasons. Total arsenic (tAs) and Mn in surface water during the dry season exceeded WHO drinking water guidelines. Total mercury (tHg) concentrations (µg/g wet wt.) in fish during the wet season (GM = 0.055; CI95 = 0.01–0.26) were approximately 15 times higher (P < 0.05) compared to those during the dry season (GM = 0.0035; CI95 = 0.0004–0.033). Mean target hazard quotients (THQs) for inorganic arsenic (iAs), methyl mercury (MeHg), Mn and Pb were > 1, with estimated maximum values greatly exceeding 1. Mean THQs of Zn, Cd, Ni and Se were very near 1, with estimated maximum values exceeding 1. The MeHg THQ (min-max range: 0.16–9.09) during the wet season was 7 times higher than in the dry season (min-max range: 0.05–1.35). Concentrations of Hg and other trace elements varied widely between fish species. The findings suggest that exposure of some trace elements via water and food is of concern in this region. High consumption rates of fish and rice key factors related to trace element exposure. Seasonal hydrology and species-specific bioaccumulation behaviour in the Tonlé Sap Lake watershed also play an important role. The generated information will be useful to better mitigate trace element exposure in this region.

Coupled Carbon, Mn(II), and Nitrogen Cycles in a Mixotrophic Biofilm Reactor and Microbial Community Structure

AbstractA novel mixotrophic biofilm reactor (MBR) was operated to simultaneously remove total organic carbon, nitrate, and Mn(II). Effects of some key factors on mixotrophic denitrification were investigated in lab‐scale bioreactors. Optimized conditions obtained from the MBR were used to validate the experiments, proving their feasibility. High‐throughput sequencing was employed to analyze the microbial communities of the MBR. The community diversity in the MBR was markedly influenced by the ratio of Cinorganic:Corganic. The species were increased with lower Cinorganic:Corganic concentration. Pseudomonas was detected as the dominant species in the MBR, indicating that Pseudomonas sp. SZF15 and Pseudomonas sp. H‐117 play a primary role in the process of nitrate removal.