Concentrations Of Br Research Articles

Halogen (F, Cl, Br, and I) Devolatilization During Prograde Subduction: Insights From Western Alps Ophiolites

AbstractIn order to examine the progressive chemical evolution of halogens (F, Cl, Br, I) in altered ocean crust (AOC) during prograde subduction, this study compares bulk and in situ halogen concentrations in mafic samples from three petrogenetically related exhumed terrains in the Western Alps (the Chenaillet ophiolite, the Queyras ophiolites of the Schistes Lustrés, and the Monviso ophiolite). Samples from the Chenaillet ophiolite represent oceanic crust unaffected by metamorphic halogen loss and define a protolith halogen content (122 μg/g F, 29 μg/g Cl, 82 ng/g Br, and 98 ng/g I). Samples from the Queyras ophiolites experienced blueschist facies conditions, undergoing recrystallization and halogen loss (74 μg/g F, 19 μg/g Cl, 70 ng/g Br, and 63 ng/g I). Eclogite facies samples from the Monviso meta‐ophiolite exhibit markedly reduced Cl (8 μg/g Cl) and Br (42 ng/g Br) contents relative to samples from Chenaillet and Queyras. Using electron probe microanalysis (EPMA), F and Cl host minerals (e.g., amphibole, chlorite, epidote) are identified and characterized in selected samples, showing a broad distribution of F and Cl, lending support to the view that halogen devolatilization in the subducting slab occurs continuously and is not dependent on the breakdown of a particular phase. In situ Cl concentrations decrease significantly between sub‐greenschist and blueschist assemblages. Fluorine is retained within subducting AOC and is decoupled from the heavy halogens (Cl, Br, I), which undergo continuous devolatilization during prograde metamorphism.

Development of a Five-Chemical-Probe Method to Determine Multiple Radicals Simultaneously in Hydroxyl and Sulfate Radical-Mediated Advanced Oxidation Processes.

Advanced oxidation processes (AOPs), such as hydroxyl radical (HO•)- and sulfate radical (SO4•-)-mediated oxidation, are attractive technologies used in water and wastewater treatments. To evaluate the treatment efficiencies of AOPs, monitoring the primary radicals (HO• and SO4•-) as well as the secondary radicals generated from the reaction of HO•/SO4•- with water matrices is necessary. Therefore, we developed a novel chemical probe method to examine five key radicals simultaneously, including HO•, SO4•-, Cl•, Cl2•-, and CO3•-. Five probes, including nitrobenzene, para-chlorobenzoic acid, benzoic acid, 2,4,6-trimethylbenzoic acid, and 2,4,6-trimethylphenol, were selected in this study. Their bimolecular reaction rate constants with diverse radicals were first calibrated under the same conditions to minimize systematic errors. Three typical AOPs (UV/H2O2, UV/S2O82-, and UV/HSO5-) were tested to obtain the radical steady-state concentrations. The effects of dissolved organic matter, Br-, and the probe concentration were inspected. Our results suggest that the five-probe method can accurately measure radicals in the HO•- and SO4•--mediated AOPs when the concentration of Br- and DOM are less than 4.0 μM and 15 mgC L-1, respectively. Overall, the five-probe method is a practical and easily accessible method to determine multiple radicals simultaneously.

High photovoltaic performance of lead-free Cs2AgInCl6-xBrx perovskite solar cell using DFT and SCAPS-1D simulations

The search of the lead-free highly efficient photovoltaic material is a key challenge for next generation solar cells. The structural, electronic, and optical properties of lead-free double perovskite Cs2AgInCl6-xBrx (x= 0,1,2,3,4,5 and 6) were investigated using density functional theory and its photovoltaic performance by using one-dimensional solar cell capacitance simulator SCAPS-1D. By increasing Br content in Cs2AgInCl6, the lattice parameter increases and the electronic band gap decreases without affecting the direct nature of band gap at Г- point. By mixing Br in Cs2AgInCl6 also provides an effective way to tune the energy band gap. In addition, increasing the Br content in mixed halide composition Cs2AgInCl6-xBrx (x= 0,1,2,3,4,5 and 6) reproduces more dispersive conduction band minima and valence band maxima result in lower effective masses of both charge carriers and consequently higher bipolar carrier mobility. The optical properties of Cs2AgInCl6-xBrx, such as absorption coefficient, reflectivity, dielectric constants, refractive index, and extinction coefficient were investigated with different Br concentrations. Among all compositions, the Cs2AgInClBr5 exhibits better optical properties and behaves as poor reflector and good absorber in the visible region. The photovoltaic performance of different absorber layers of Cs2AgInCl6-xBrx compositions in the perovskites solar cell module with configuration FTO/ETL/Cs2AgInCl6-xBrx /HTL/Au is analysed by using the SCAPS-1D. It is also observed that Cs2AgInClBr5 has high bipolar carrier mobility, relatively higher stability and direct band gap value of 1.75 eV with the PCE of 21.95% in the visible region indicate the suitability of the Cs2AgInClBr5 as a promising lead-free photovoltaic material.

Primary and residual impacts of phosphoric acid modified biochar on growth and concentrations of essential and non-essential elements in lettuce and second crop arugula

The study aimed to explore how phosphoric acid-modified rice husk biochar (PBC) affects the growth and concentrations of essential and non-essential elements in two crops: lettuce as the primary crop and arugula as the secondary crop. The treatments consisted of a no P fertilized control and 250 mg P kg−1 sourced either from PBC, triple super phosphate (TSP) or phosphoric acid (PA). When subjected to phosphorus (P) sources, both lettuce and arugula exhibited a noteworthy rise in their dry weights compared to the control plants. PBC treatments significantly increased P concentration in both plants. Although the PBC treatment decreased lettuce nitrogen (N) concentration, it had no impact on arugula N concentration. Phosphorus treatments resulted in a decrease in lettuce K concentration, whereas it increased in arugula. Calcium (Ca), magnesium (Mg) and sulfur (S) concentrations in both plants were not affected by P sources. The zinc (Zn) concentrations of the plants notably decreased with P treatments. Moreover, P treatments led to a reduction in manganese (Mn) concentration specifically in arugula. PBC significantly increased the silicon (Si) concentrations of lettuce plants. The application of PA significantly increased the vanadium (V) concentration in arugula. Phosphoric acid treatments resulted in an increase in the plant bromine (Br) concentrations. To conclude, PBC may serve as an alternative P source, potentially being as effective as or even more effective than other P sources in influencing plant nutrition, without causing an undesirable elevation of non-essential elements in plants.

Accumulation of Heavy Metals and Determination of Natural Radioactivity in the Soil-Thyme System in Omerli, Istanbul: Assessment of Ecological and Health Risk

A significant pathway for human exposure to environmental pollutants is the metal transfer from soil to plants. In this study accumulation of different metals was investigated and natural radioactivity levels were measured in the soil–thyme system. It was found that the soil had higher concentrations of Br, Cr, Mn, Ni, and Pb than the world average and P, Ca, and Zn had higher transfer factors. The natural radioactivity level in the soils is similar to the World average. For thyme samples the average values for 226Ra, 232Th and 40K were found as 22.7 ± 10.9 Bqkg-1, 61.3 ± 19.9 Bqkg-1 and 722 ± 391 Bqkg-1, respectively. The health and ecological risks of soil were evaluated. The total hazard index of the child was 1.453 on average, greater than that of the adult (0.175), primarily due to the contribution of Cr. Ecological risk assessed based on various indices indicated that Pb and Ni show environmental contamination risk. Our findings confirm that metal concentrations in plants are influenced by metal concentrations in soil, and that metal interactions are important for pollution risk management.

Impact of photoinduced phase segregation in mixed-halide perovskite absorbers on their material and device stability

Mixed-halide perovskites enable bandgap engineering for tandem solar cell and light-emitting diode applications. However, photoinduced halide phase segregation introduces a compositional instability, that is, formation of I-rich and Br-rich phases, which compromises photovoltaic efficiency and stability. While optical and structural studies of the photoinduced phase segregation in mixed-halide perovskites have been reported, its impact on the material stability is missing. Here, a detailed compositional analysis of mixed-halide perovskite films using x-ray and ultraviolet photoelectron spectroscopy (UPS) was carried out to determine how their stability in various environments depends on the halide ratio. A series of perovskite thin films were fabricated with the composition CH3NH3Pb(IxBr1−x)3, where x = 0.00, 0.25, 0.50, 0.75, and 1.00, and analyzed under different conditions, such as exposure to light in ambient and in nitrogen atmosphere, as well as storage in the dark. From the spectroscopy results, complemented with structural and optical properties, it was found that the deletion of halide ions from the surface is facilitated in mixed-halide perovskites in comparison with pure halide perovskites. A higher stability was found for the mixed-halide perovskite containing less than 25% Br, and it decreases with increasing Br content. This study also established the effect of the Br/I ratio on the energy landscape of the materials. The UPS spectra reveal that photoinduced degradation results in a mismatch of the energy levels at the perovskite/transport layer interface, which may limit the collection of charge carriers. These findings correlate well with the photovoltaic device stability under similar degradation conditions.

Mixing I and Br in Inorganic Perovskites: Atomistic Insights from Reactive Molecular Dynamics Simulations.

All-inorganic halide perovskites have received a great deal of attention as attractive alternatives to overcome the stability issues of hybrid halide perovskites that are commonly associated with organic cations. To find a compromise between the optoelectronic properties of CsPbI3 and CsPbBr3, perovskites with CsPb(BrxI1-x)3 mixed compositions are commonly used. An additional benefit is that without sacrificing the optoelectronic properties for applications such as solar cells or light-emitting diodes, small amounts of Br in CsPbI3 can prevent the inorganic perovskite from degrading to a photo-inactive non-perovskite yellow phase. Despite indications that strain in the perovskite lattice plays a role in the stabilization of the material, a full understanding of such strain is lacking. Here, we develop a reactive force field (ReaxFF) for perovskites starting from our previous work for CsPbI3, and we extend this force field to CsPbBr3 and mixed CsPb(BrxI1-x)3 compounds. This force field is used in large-scale molecular dynamics simulations to study perovskite phase transitions and the internal ion dynamics associated with the phase transitions. We find that an increase of the Br content lowers the temperature at which the perovskite reaches a cubic structure. Specifically, by substituting Br for I, the smaller ionic radius of Br induces a strain in the lattice that changes the internal dynamics of the octahedra. Importantly, this effect propagates through the perovskite lattice ranging up to distances of 2 nm, explaining why small concentrations of Br in CsPb(BrxI1-x)3 (x ≤ 1/4) have a significant impact on the phase stability of mixed halide perovskites.

Ferrate(VI) assists in reducing cytotoxicity and genotoxicity to mammalian cells and organic bromine formation in ozonated wastewater

Ozonation of wastewater containing bromide (Br−) forms highly toxic organic bromine. The effectiveness of ozonation in mitigating wastewater toxicity is minimal. Simultaneous application of ozone (O3) (5 mg/L) and ferrate(VI) (Fe(VI)) (10 mg-Fe/L) reduced cytotoxicity and genotoxicity towards mammalian cells by 39.8% and 71.1% (pH 7.0), respectively, when the wastewater has low levels of Br−. This enhanced reduction in toxicity can be attributed to increased production of reactive iron species Fe(IV)/Fe(V) and reactive oxygen species (•OH) that possess higher oxidizing ability. When wastewater contains 2 mg/L Br−, ozonation increased cytotoxicity and genotoxicity by 168%-180% and 150%-155%, respectively, primarily due to the formation of organic bromine. However, O3/Fe(VI) significantly (p < 0.05) suppressed both total organic bromine (TOBr), BrO3−, as well as their associated toxicity. Electron donating capacity (EDC) measurement and precursor inference using Orbitrap ultra-high resolution mass spectrometry found that Fe(IV)/Fe(V) and •OH enhanced EDC removal from precursors present in wastewater, inhibiting electrophilic substitution and electrophilic addition reactions that lead to organic bromine formation. Additionally, HOBr quenched by self-decomposition-produced H2O2 from Fe(VI) also inhibits TOBr formation along with its associated toxicity. The adsorption of Fe(III) flocs resulting from Fe(VI) decomposition contributes only minimally to reducing toxicity. Compared to ozonation alone, integration of Fe(VI) with O3 offers improved safety for treating wastewater with varying concentrations of Br−.

Halogen Cycling in the Solid Earth

Each of the halogens constrains a different aspect of volatile cycling in the solid Earth. F is moderately incompatible in the mantle and has a low mobility at Earth's surface, meaning that it is preferentially retained in the mantle and continental crust. In contrast, Cl, Br, and I are strongly incompatible and highly soluble. Chloride is the dominant anion in seawater and many geofluids and a major component of evaporite minerals. Br and I are essential for life and significantly incorporated into organic matter that accumulates in marine sediments. Surficial fluids circulated into continental and oceanic crust incorporate surface-derived halogens into alteration minerals. As a result, subducting slabs and arc lavas are weakly enriched in F and strongly enriched in Cl, Br, and I. Subduction has maintained mantle Cl and Br concentrations at relatively constant levels since Earth's early differentiation, but mantle I/Cl has decreased over time. ▪Halogen abundances on the early Earth were affected by I partitioning into Earth's core and possible loss of hydrophilic Cl, Br, and I in an early formed ocean.▪Halogens are powerful tracers of subduction zone processes on the modern Earth, with Cl, Br, and I having a dominantly subducted origin in Earth's mantle.▪The deep subduction cycles of Cl, Br, and I are more similar to that of H2O than they are to F, but the geochemical cycle of each halogen differs in detail.▪Halogen abundance ratios and stable isotope ratios vary systematically in Earth's surface reservoirs, meaning that halogens are powerful tracers of geological fluids and melts.

Geochemical characteristics of shale gas hydraulic fracturing flowback/produced water in Zheng’an block, northern Guizhou Province, China

Guizhou Province of China is rich in shale gas resources. In recent years, important progress has been made in the exploration and development of shale gas in the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation in Zheng'an block in northern Guizhou, adjacent to Sichuan Basin. Due to the complex geological conditions and fragile ecological environment in the shale gas distribution area, serious environmental pollution risks may exist in shale gas exploitation. Therefore, this paper conducted element, hydrogen and oxygen isotope analyses for shale gas fracturing flowback/produced water of Well AY7-4 in Zheng'an block. The results showed that the contents of K, Na, Ca, Mg and NH4+ in the flowback/produced water of Well AY7-4 were very high, with an average of 118 mg/L, 7616 mg/L, 266 mg/L, 47 mg/L and 76 mg/L, respectively. The content of Na, Ca and Mg is similar to that of shale gas flowback/produced water in Weiyuan, but lower than that in Changning and Fuling. NH4+ content was similar to that in Changning, but much higher than that in Weiyuan. The average Cl content was 11605 mg/L, which was similar to that in Weiyuan, but lower than that in Changning and Fuling. The average Br content is 48 mg/L, slightly lower than that of Weiyuan, and about half of that of Changning and Fuling. Correspondingly, the Br/Cl value of Well AY7-4 is the lowest, reflecting its relatively low Br content. The average content of Li, B and Sr is 17 mg/L, 10 mg/L and 45 mg/L, respectively, which is similar to that of the Weiyuan, Changning and Fuling shale gas fields. The distribution model of Li and Sr is similar to that of Cl, Br and Na, but the B content and B/Cl value of Well AY7-4 are the lowest. The linear relationship between Br and Cl contents and between δD and δ18O of flowback/produced water of Well AY7-4, freshwater used for hydraulic fracturing and hydraulic fracturing injected fluid indicates that flowback/produced water of Well AY7-4 is mainly the mixed product between low salinity injected fracturing fluid and high salinity brine retained in shale formation. The hydrogen and oxygen isotopic compositions gradually become heavier over time, indicating that the proportion of high salt end formation brine in flowback/produced water is increasing. The contents of Cl, Br, Na and NH4+ in the flowback/produced water of Well AY7-4 are far higher than the allowable discharge value, which is a potential environmental pollution risk and cannot be discharged directly.

Enhanced oil dehalogenation during catalytic pyrolysis of WEEE-derived plastics over Fe- and Ca-modified zeolites

Pyrolysis affords the conversion of plastics from Waste of Electrical and Electronic Equipment (WEEE) into oils with potential applications in the production of valuable chemicals and the formulation of liquid fuels. However, the presence of significant concentrations of halogens (Cl and Br) in these wastes represents an important limitation as it can lead to the generation of hazardous species that negatively affect the environment. In this work, the catalytic pyrolysis of a real WEEE plastic has been investigated using a reaction system that operates with continuous feeding of the raw material. The catalysts assayed include bulk metal oxides (Fe2O3 and CaO) and zeolites (ZSM-5 and USY), as well as hybrid solids obtained by supporting those metal oxides on the zeolites. Pre-treatment of the raw WEEE plastics by water washing allows the Cl concentration to be significantly reduced, but it does not affect the Br content. Thermal pyrolysis produces an oil fraction with a high yield (> 70 wt%) and a large concentration of halogens (700 ppm), even though the char produced effectively retains more than 90% of Br and Cl contained in the feedstock. During catalytic pyrolysis, the halogen content of the oil is further reduced obtaining the best dehalogenation results with the metal-modified zeolites. This fact evidences a synergetic effect derived from the high metal dispersion achieved over the zeolitic supports. Fe/ZSM-5 is the most promising catalyst, showing an almost constant dehalogenation activity along the time-on-stream and producing an oil enriched in monoaromatic hydrocarbons (mainly styrene).

Orientation of Thiocyanate Ions Tuning the Electron-Phonon Interactions in Pseudohalide Perovskites.

Although the importance of electron-phonon interactions on the optoelectronic properties of perovskites has been well documented, the structural origin of electron-phonon interactions remains largely unexplored. In this study, using pseudohalide perovskites Cs2Pb(SCN)2I2(1-x)Br2x as a model, we have revealed how the orientation of SCN- anions tunes the electron-phonon interactions and the effective charge-carrier mobility by utilizing femtosecond sum frequency generation vibrational spectroscopy, supplemented by photoluminescence spectroscopy and femtosecond optical-pump terahertz-probe spectroscopy. The coupling between neighboring SCN- anions decreases as the Br content (x) increases but does not have a significant effect on the electron-phonon interactions. In contrast, the orientation angle of SCN- anions has a strong correlation with the electron-phonon interaction and effective charge-carrier mobility, that is, a more parallel orientation of SCN- anions leads to a higher electron-phonon interaction and lower effective charge-carrier mobility. This finding provides a molecule-level understanding of the inorganic lattice structure in tuning electron-phonon interactions and may offer valuable guidance for optimizing the optoelectronic properties of perovskites.

Bromine functionalization of metal–organic frameworks to improve ethane/ethylene separation

Metal–organic frameworks (MOFs) have undergone extensive study as ethane-selective adsorbents for ethane/ethylene (C2H6/C2H4) separation, a process currently conducted through energy-intensive cryogenic distillation in the petrochemical industry. Herein, we present the effect of functionalization using bromine, known for its high polarizability, on the C2H6-selective adsorption properties of MOF. This approach, based on the slightly larger polarizability of C2H6 compared to C2H4, was systematically investigated using three isostructural MOFs: DMOF-1, DMOF-1-Br, and DMOF-1-Br2, featuring 1,4-benzenedicarboxylate, 2-bromo-1,4-benzenedicarboxylate, and 2,5-dibromo-1,4-benzenedicarboxylate ligands, respectively. While their C2H6/C2H4 selectivity, based on the ideal adsorbed solution theory, increased (from 1.51 to 1.75 at 298 K and 100 kPa for the 1/1 (v/v) mixture) with the rising Br content, breakthrough experiments revealed that DMOF-1-Br achieves the highest high-purity (>99.95 %) C2H4 productivity (9.7 LSTP kg−1 at 298 K and 100 kPa for the 1/1 mixture and 22.2 LSTP kg−1 for the 1/15 mixture). This accomplishment is attributed to the appropriate bromine functionalization. Further insight into their C2H6-selective adsorption behavior was gained through canonical Monte Carlo and dispersion-corrected density functional theory simulations.

Structural, electronic, optical, and thermoelectric properties of CsPbI3-yBry (y = 0.5, 1.5, 2.5) compounds: First-principle study

BackgroundAmong photovoltaic materials, halide-based perovskites, such as CsPbI3, have been the subject of many research papers due to their suitable and direct bandgap, very good optical properties, and remarkable thermoelectric properties. Enhancing optoelectronic and thermoelectric properties can be achieved by combining halide atoms intelligently. The purpose of this article is to examine the physical properties of Br substitution at different concentrations in CsPbI3 perovskite. MethodsThe structural, electrical, and optical properties of CsPbI3-yBry (y = 0.5, 1.5, 2.5) compounds have been investigated by using the QUANTUM-ESPRESSO/PWSCF computational package which is based on the density functional theory and the pseudo-potential technique. The thermoelectric properties of CsPbI3-yBry perovskites were calculated by solving the Boltzmann transport equations within the constant relaxation time approximation as employed in the BoltzTraP package. Significant findingsThe structural investigation reveals that when the I atom is substituted by Br, the lattice constant decreases, increasing the bulk modulus and stiffness of compounds. The calculated negative formation energy confirmed the thermodynamic stability of CsPbI3-yBry compounds, and the stability improved with an increase in Br concentration. The electronic investigation indicates the semiconductor nature of compounds with a direct band gap, with a slight increase in electronic band gap as Br concentration increases. The noticeable optical absorption coefficient in the visible range of the electromagnetic spectrum, along with high and tunable optical conductivity, confirms the capability of the compounds for use in optoelectronic devices. The positive value of the Seebeck coefficient revealed the p-type semiconducting nature of CsPbI3-yBry perovskites. Lattice thermal conductivity calculation reveals that this quantity is decreased because of the increase in phonon-phonon interaction due to rising temperature. Thermoelectric investigation indicates that a precise mixture of halide I and Br atoms significantly enhances the electrical and thermal conductivity of perovskites. Also, the substitution of halide I atoms by Br can improve the figure of merit (ZT). The maximum value of ZT at room temperature is equal to 0.99, justifying the brilliant thermoelectric properties of the studied compounds.

A probabilistic approach to compare the risk associated with heavy metals and bromine in honey from Dominican Republic, Mexico, Mozambique and Spain

This study aims to analyse the risk to consumers given the presence of heavy metals and bromine in honey from different countries. A probabilistic approach was applied to assess carcinogenic risk. Concerning exposure, Al in Spain (3.3E-04 mg/kgBw/day), B in Dominican Republic and Mexico (2E-04 mg/kgBw/day in both cases) and Fe in Mexico and Mozambique had the highest values (5E-05 and 4.8E-05 mg/kgBw/day). In risk characterisation, the values were less than 1 for hazard index (HI), meaning that the consumption of honey represents a low level of concern for non-genotoxic effects. A combination of margin of exposure and probability of exceedance results that exposure to Pb pose no threat. The probability of suffering cancer for Br, Cd, Ni and Pb was lower than 1.0E-06 and, therefore, considered safe. However, the risk at the 95th percentile of Br in Dominican Republic was 1.18E-04 in adults and 2.45E-04 in children, exceeding 1.0E-04, and therefore, considered intolerable. Finally, the sensitivity analysis indicated that the most influential factor in the HI was the consumption in adults and the concentration of Ni in children, whereas for cancer risk, were the concentrations of Ni, Cd, Br and Pb, in both cases.

An in-situ experimental HP/HT study on bromine release from a natural basalt

We present the first in-situ partitioning data for bromine between a natural basaltic melt and a coexisting fluid. For this study hydrothermal diamond anvil cell experiments at pressures up to 1.7 GPa were conducted. We combined laser heating to melt the basalt glass with external heating to lower the temperature gradient in the cell and to initiate circulation for the aqueous fluid. Bromine concentrations were measured in-situ with X-ray fluorescence in the basaltic melts, glasses, and in the fluid. From the results we calculated partition coefficients of DBrfluid/melt = 1.19 to 3.92 in the range of 0.4 to 1 GPa for aqueous fluids. Experiments with neon as the surrounding fluid (DBrfluid/melt = 0.38 ± 0.01 at 1.1 GPa) suggest that Br-release from a basalt into volatiles that have no bonding affinity with Br is weak. This should be the case for dry intra-plate volcanic eruptions. From the experimentally gained partition coefficients and from global Br concentration values in melt inclusions of arc magmas, we calculated an annual global Br flux of 23.5–72.9 × 109 g/y.

Crop bromide concentrations following methyl bromide fumigation for pale cyst nematode in southeastern Idaho.

Methyl bromide (MeBr) is a sterilizing fumigant used to control quarantine pests that is restricted due to its detrimental atmospheric effects. The degradation of injected MeBr produces crop-available Br- . Up to five applications of MeBr were used in southeastern Idaho fields to combat the pale cyst nematode (Globodera pallida). Data regarding the uptake and partitioning of Br- in crops following MeBr application in the region were unavailable. Research determined background concentrations of Br- in alfalfa (Medicago sativa L.), barley (Hordeum vulgare L.), corn (Zea mays L.), potato (Solanum tuberosum L.), and wheat (Triticum aestivum L.) compared to MeBr-treated fields. Background Br- concentrations ranged from nondetectable (ND) to 33.0mg Br- kg-1 ; vegetative tissue concentrations were greater than reproductive, except corn where there was no difference. Nearly all crops grown in MeBr-treated fields had greater Br- concentrations than background. Background-baled-alfalfa tissue Br- concentration was 33.0mg kg-1 compared to 117.8mg Br- kg-1 from a MeBr-treated field. Br- concentration in green alfalfa decreased from 79.8 to 36.5mg Br- kg-1 at the final cutting in a MeBr-treated field, where time after application decreased crop Br- concentrations. Small grains had low Br- concentrations in reproductive tissue (1.7mg Br- kg-1 ) compared to vegetative tissue (106.5mg Br- kg-1 ). Corn stover concentration (12.7mg Br- kg-1 ) was low relative to small-grain straw, but corn ear (5.8mg Br- kg-1 ) was greater than small-grain reproductive tissue in the MeBr-treated field. Crop selection following MeBr applications should consider the likelihood of elevated Br- concentration for the plant fractions intended end use.

Coupling water, solute, and sediment transport into a new computationally efficient hydrologic model

While surface–subsurface interactions strongly impact water quality and quantity in ecosystems, only relatively little attention has been given to solute mass transfers at this boundary. The KINEROS2 (K2) model solves the 1D kinematic wave equation for water flow and the advection–dispersion equation for non-absorbing solute (or sediment) transport at the surface, whereas the HYDRUS-1D (H1D) model solves the Richards equation for flow and the advection–dispersion equation for solute transport in the subsurface. We previously coupled water flow in the surface and subsurface environments using the K2 and H1D models (H1D-K2). Herein, an innovative framework was developed to additionally couple solute transport at the surface–subsurface boundary in the simple, accurate, and computationally efficient H1D-K2 model. To test the H1D-K2 model’s accuracy and robustness, simulation results are compared to analytical solutions, experimental data, and results from the two-dimensional HYDRUS-2D (H2D) code. The relative differences in water and solute balance components between the H2D and H1D-K2 models are less than 1% for homogeneous cases and 4% for heterogeneous cases. The simulated hydrograph and chemograph are almost identical for the two models. Furthermore, simulated Bromide (Br) concentration in runoff is in good agreement with observations. The proposed model also accurately reproduces soil erosion under different rainfall patterns and intensities.

Origin of lithium in oilfield brines in continental petroliferous basin: Insights from Li and Sr isotopes in the Jianghan Basin, central China

Oilfield brines are a significant alternative lithium resource to meet the global demand in the next decades. However, their metallogenic characteristics and mechanism remain unclear. To constrain the source and enrichment process, this study presents chemical and multi-isotope data for oilfield brines from the Middle Eocene to Lower Oligocene Qianjiang Formation of the Jianghan Basin, central China. These formation water samples collected from 159 oil wells have salinities of 47–355 g/L and lithium contents of 5.36–150.00 mg/L. The good linear relationship between δD and δ18O values indicates that the salinities are achieved by dilution of the primary brine by meteoric water. Waters from the lower of the Qianjiang Formation have higher δD and δ18O values and 87Sr/86Sr ratios than those from the upper, in conjunction with the low correlation between the δD and δ18O value and the salinity and between the Sr content and the 87Sr/86Sr ratio, indicating the impact of associated water-rock interactions. Moreover, contributions from diagenetic processes of dolomitization, dissolution of evaporites and albitization are also indicated by the high Cl/Br mass and Na/Cl molar ratios and the Ca excess and Na deficit. Chemical geothermometers give reservoir temperature values of 118 °C and 138 °C on average for the oilfield brines from the upper and lower formation, respectively. The binary linear relationships between Li contents and TDS values and Br contents imply specific enrichment processes in addition to evapo-concentration. Variations in δ7Li values (+10.6‰–+21.3%) and 87Sr/86Sr ratios (0.709479–0.711516) were used to trace the process of Li enrichment in oilfield brines. The lower δ7Li values with more enriched Li in comparison to Na indicate a significant lithium input from clastic host rocks, which is also confirmed by the fact that more radiogenic waters have relatively lower δ7Li values. Overall, these results suggest that Li enrichment in the Qianjiang oilfield brines was generated by the interaction of Li-bearing minerals in the clastic host rocks with water formed by original evaporitic brines diluted by meteoric water. This work represents a significant role of lithium and strontium isotopic systematics in elucidating the Li origins of deep-seated oilfield brines in continental petroliferous basins.

Elemental concentrations of seven types of green vegetables grown on small-scale farmlands in rural areas of Japan: Differences according to the type and place of production

We collected seven types of green vegetables produced in 11 areas of Japan and analyzed their elemental concentrations. Halogen analyses were performed with and without prior chemical treatment. The most popular type of spinach exhibited the highest concentrations of Mg, K, and Zn, and the lowest concentrations of alkaline earths (Ca and Sr) and halogens (Cl and Br). Japanese mustard spinach, the second most consumed type of spinach in Japan, exhibited the highest concentrations of P, S, Ca, Fe, and Br and adequate amounts of other essential elements. The other five green vegetables had unique elemental concentrations. In particular, radish had the highest concentrations of Ca, Na, and Cl and the lowest concentrations of Mg, P, Cu, and Zn. Leaves and stalks were separately analyzed. Fe, Cu, Zn, and Mn concentrations tended to be higher in leaves, and K, Na, and Rb concentrations were higher in stalks. Halogen (Cl and Br) concentrations in Japanese mustard spinach produced on farmland near the coast were remarkably high, suggesting an effect of sea salt. However, even in green vegetables produced near the coast, halogen uptake clearly differed by production area. The concentrations of Cl and Br in Japanese mustard spinach produced in two coastal areas were very high and were not removed by washing, but were mostly lost after boiling samples from Taneichi for 3[Formula: see text]min. In contrast, there was no difference in Na concentrations among vegetables produced in coastal and inland areas. The concentrations of essential elements such as Mg, Ca, and Fe were clearly higher in green vegetables from small- versus large-scale production areas, perhaps attributable to differences in the farming methods employed.