Bromine Research Articles

Bromine speciation in volcanic plumes: new in situ derivatization LC-MS method for the determination of gaseous hydrogen bromide by gas diffusion denuder sampling

Abstract. The chemical characterization of volcanic gas emissions gives insights into the interior of volcanoes. Bromine species have been correlated with changes in the activity of a volcano. In order to exploit the volcanic bromine gases, we need to understand what happens to them after they are outgassed into the atmosphere. This study aims to shed light on the conversion of bromospecies after degassing. The method presented here allows for the specific analysis of gaseous hydrogen bromide (HBr) in volcanic environments. HBr is immobilized by reaction with 5,6-epoxy-5,6-dihydro-[1,10]-phenanthroline (EP), which acts as an inner coating inside of diffusion denuder tubes (in situ derivatization). The derivative is analyzed by high-performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS). The collection efficiency for HBr (99.5 %), the collection efficiency for HBr alongside HCl (98.1 %), and the relative standard deviation of comparable samples (8 %) have been investigated. The comparison of the new denuder-based method and Raschig tubes as alkaline traps resulted on average in a relative bias between both methods of 10 ± 6 %. The denuder sampling setup was applied in the plume of Masaya (Nicaragua) in 2016. HBr concentrations in the range between 0.44 and 1.97 ppb were measured with limits of detection and quantification below 0.1 and 0.3 ppb respectively. The relative contribution of HBr as a fraction of total bromine decreased from 75 ± 11 % at the Santiago crater (214 m distance to the volcanic emission source) to 36 ± 8 % on the Nindiri rim (740 m distance). A comparison between our data and the previously calculated HBr, based on the CAABA/MECCA box model, showed a slightly higher trend for the HBr fraction on average than expected from the model. Data gained from this new method can further refine model runs in the future.

Evaluation of twenty chemical element contents in thyroid adenomas using neutron activation analysis and inductively coupled plasma atomic emission spectrometry

Thyroid adenomas (TA) are benign tumors, but there is a 20% possibility of malignant transformation. The distinguishing between the TA and thyroid cancer (TC) is tricky, therefore new TA biomarkers are needed. Furthermore, the role of chemical elements (ChE) in etiology and pathogenesis of TA is unclear. The aim of this exploratory study was to evaluate whether significant changes in the thyroid tissue levels of twenty chemical elements (ChE) Al, B, Ba, Br, Ca, Cl, Cu, Fe, I, K, Li, Mg, Mn, Na, P, S, Si, Sr, V, and Zn exist in the adenomatous transformed thyroid. Thyroid tissue levels of twenty ChE were prospectively evaluated in 19 patients with TA and 105 healthy inhabitants. Measurements were performed using a combination of non-destructive and destructive methods: instrumental neutron activation analysis and inductively coupled plasma atomic emission spectrometry, respectively. Tissue samples were divided into two portions. One was used for morphological study while the other was intended for ChE analysis. It was found that contents of of Al, B, Br, Cl, Cu, Na, and Zn are significantly higher whereas the levels of I some lower. in TA than in normal tissues. It was supposed that the changes in levels Al, B, Br, Cl, Cu, I, Na, and Zn in thyroid tissue can be used as TA markers.

Degradation of organic filter 2-Phenylbenzidazole-5-Sulfonic acid by light-driven free chlorine process: Reactive species and mechanisms

This study investigated the degradation of organic filter 2-phenylbenzidazole-5-sulfonic acid (PBSA) under ultraviolet and simulated sunlight activated free chlorine (UV/FC and SS/FC) in different water matrices. A mechanistic study revealed that ozone, HO•, Cl• and ClO• were responsible for PBSA degradation, and reactive chlorine species (RCS) played a major role. The developed mathematical model was utilized to estimate the rate constants of PBSA with representative radical species and predict the kinetics of PBSA attenuation well. Observed PBSA loss rate constants (kobs) decrease with pH during UV/FC due to the high quantum yield and weak radical scavenging ability of hypochlorite (pKa = 7.5), while there is little difference under SS/FC. Furthermore, formation of reactive oxidants (HO•, Cl•, ClO• and ozone) during FC photolysis as a function of pH (5–10) were quantified with probe compounds. In seawater matrix, kobs for PBSA degradation under UV/FC (0.0109 min−1) was two times lower than that under SS/FC (0.0244 min−1) because the highly abundant HCO3–, Br- and Cl- exhibited a stronger inhibition (76%) for the former. A screening test showed that NaBr and NaBr + NaHCO3 during SS/FC displayed the reinforcement effects, primarily due to the interaction between reactive bromine species and the imidazole moiety in PBSA. Based on these identified products, transformation pathways of PBSA included hydroxylation, ring cleavage and desulfonate. This work provided mechanistic insight into PBSA degradation by reactive species formed through FC photoactivation, and suggest a promise of SS/FC for efficient abatement of organic filters-caused seawater pollution for realistic application.

Evaluation of flame retardancy and flexural property on prepared plastic disks containing known concentrations of flame retardants through simulated weathering tests

The standardized acrylonitrile-butadiene-styrene (ABS) or polycarbonate (PC) resin disk with added flame retardants (FRs) has a potential to be a suitable tool for predictions of both aging of the plastic materials and release rate of a flame retardants exposed under different outdoor and indoor conditions. The experiments examined the dynamics and kinetics of the release of dechlorane plus, tetrabromobisphenol A, triphenyl phosphate and antimony trioxide as FRs from a standardized plastic disk before and after exposure to artificial sunlight. Assessments were carried out independently to measure changes in the content of flame retardants and monitor the flame retardancy and flexural properties after exposure (60 W/m2) over a period of 200 h and 500 h, which are reasonable to predict a short-time tendency and to receive any advice for a safe re-use. The releases of three organic flame retardants and four elements (Cl, Br, P and Sb) from weathered ABS and PC disks were very limited, except for surface delamination and resin microparticles. Triphenyl phosphate was stable without hydrolysis, while the degradation of tetrabromobisphenol A was observed (approximately 20% decrease for ABS disk and approximately 50% decrease for PC disk). During the study, no significant differences in the flame retardancy and flexural properties of the disks could be detected. In practice, the results obtained from disks of acrylonitrile-butadiene-styrene or polycarbonate resin with selected flame retardants used in specific conditions may provide technical expertise regarding weathering processes.

COMPARISON OF LEVELS OF TWENTY CHEMICAL ELEMENTS IN NORMAL THYROID TISSUE AND HYPERTROPHIC THYROID TISSUE

Background: Goiter can appear as a palpable or visible enlargement of the thyroid gland at the base of the neck. If the goiter is accompanied by hypothyroidism or hyperthyroidism, it may be accompanied by symptoms of the underlying disorder, and nodular goiter (NG) is a health problem of international importance. The aim of this exploratory study was to assess whether there were significant changes in thyroid tissue levels of twenty chemical elements (ChE) Al, B, Ba, Br, Ca, Cl, Cu, Fe, I, K, Li, Mg, Mn , Na, P, S, Si, Sr, V, and Zn are present in the goitrous transformed thyroid. Methods: Thyroid tissue level of twenty ChE was prospectively evaluated in 46 patients with NG and 105 healthy populations. The measurements were performed using a combination of non-destructive and destructive methods: instrumental neutron activation analysis and inductively coupled plasma atomic emission spectrometry, respectively. Tissue samples were divided into two parts. One was used for morphological study while the other was for ChE analysis. Results: It was found that contents of Al, B, Br, Cl, Cu, Fe, Li, Mg, Mn, Na, P, S, Si, V, and Zn are significantly higher while the I levels are lower in NG than in normal tissues. Conclusion: There are considerable changes in ChE contents in goitrous tissue of thyroid. Thus, it is reasonable to assume that the levels of these ChE in thyroid tissue can be used as NG markers. However, this topic needs additional studies. Peer Review History: Received: 19 July 2021; Revised: 11 August; Accepted: 4 September, Available online: 15 September 2021 Academic Editor: Ahmad Najib, Universitas Muslim Indonesia, Makassar, Indonesia, ahmad.najib@umi.ac.id UJPR follows the most transparent and toughest ‘Advanced OPEN peer review’ system. The identity of the authors and, reviewers will be known to each other. This transparent process will help to eradicate any possible malicious/purposeful interference by any person (publishing staff, reviewer, editor, author, etc) during peer review. As a result of this unique system, all reviewers will get their due recognition and respect, once their names are published in the papers. We expect that, by publishing peer review reports with published papers, will be helpful to many authors for drafting their article according to the specifications. Auhors will remove any error of their article and they will improve their article(s) according to the previous reports displayed with published article(s). The main purpose of it is ‘to improve the quality of a candidate manuscript’. Our reviewers check the ‘strength and weakness of a manuscript honestly’. There will increase in the perfection, and transparency. Received file: Reviewer's Comments: Average Peer review marks at initial stage: 6.5/10 Average Peer review marks at publication stage: 8.0/10 Reviewers: Prof. Dr. Hassan A.H. Al-Shamahy, Sana'a University, Yemen, shmahe@yemen.net.ye Prof. Cyprian Ogbonna ONYEJI, Obafemi Awolowo University, Ile-Ife, Nigeria, conyeji@oauife.edu.ng Similar Articles: VITAMIN A, RETINOIC ACID AND TAMIBAROTENE, A FRONT TOWARD ITS ADVANCES: A REVIEW

Enhanced Performance of Zn/Br Flow Battery Using N-Methyl-N-Propylmorpholinium Bromide as Complexing Agent.

Redox flow batteries (RFB) are one of the most interesting technologies in the field of energy storage, since they allow the decoupling of power and capacity. Zinc–bromine flow batteries (ZBFB) are a type of hybrid RFB, as the capacity depends on the effective area of the negative electrode (anode), on which metallic zinc is deposited during the charging process. Gaseous bromine is generated at the positive electrode (cathode) during the charging process, so the use of bromine complexing agents (BCA) is very important. These BCAs are quaternary amines capable of complexation with bromine and generating an organic phase, immiscible with the aqueous electrolyte. One of the most commonly used BCAs in RFB technology is 4-methylethylmorpholinium bromide (MEM-Br). In this work, an alternative quaternary amine 4-methylpropylmorpholinium bromide (MPM-Br) was studied. MPM-Br was integrated into the electrolyte, and 200 charge–discharge cycles were performed on the resulting ZBFBs. The obtained results were compared with those when MEM-Br was used, and it was observed that the electrolyte with MPM-Br displays a higher resistance in voltage and higher energy efficiency, making it a promising alternative to MEM-Br.

Mechanistic and kinetic understanding of micropollutant degradation by the UV/NH2Cl process in simulated drinking water

The UV/monochloramine (UV/NH2Cl) process has attracted increasing attention in water treatment, in which hydroxyl radicals (HO•), reactive chlorine species (RCS) and reactive nitrogen species (RNS) are produced. This study investigated the effects of water matrices including halides, natural organic matter (NOM), alkalinity and pH, on the degradation kinetic of a variety of micropollutants and radical chemistry in the UV/NH2Cl process. The presence of chloride blunted HO• and Cl• impacts, but enhanced Cl2•- effect on micropollutants reactive toward Cl2•-. The presence of 30 μM bromide led to an 82% decrease in the specific pseudo-first-order rate constants (k') by HO• (kHO•'), and significantly diminished RCS efficacy. Reactive bromine species (RBS) were formed in the presence of bromide, while the contribution could not compensate for the decrease of HO• and RCS due to their lower reactivity toward micropollutants. Iodide rapidly transformed to HOI via reacting with NH2Cl, which resulted in a 59% decrease of kHO•' and 12% ∼ 100% decreases of k' by reactive halogen species (RHS) and RNS (kRHS+RNS') for most micropollutants. Nevertheless, k' of phenolic compounds, such as paracetamol, bisphenol A and salbutamol, increased in the presence of iodide by 78%, 360% and 130%, respectively, due to the roles of HOI and reactive iodine species (RIS). Bicarbonate decreased the contributions of HO• and RCS, but enhanced that of CO3•- for micropollutants reactive toward CO3•-. The presence of 1 mg/L NOM scavenged over half the amount of HO•, and also consumed RCS and RNS, resulting in significantly decreased removal of micropollutants. High pH value witnessed enhanced degradation for those micropollutants reactive toward RCS and RNS through deprotonation. The degradation of most micropollutants was inhibited in real drinking water and in the coexistence of halides. This study provides a better understanding of radical chemistry in the UV/NH2Cl process under a practical water treatment condition.

Improvement of bromide ions on the degradation of sulfamerazine by horseradish peroxidase-H2O2 system and its interaction mechanisms

Degradation of sulfonamide antibiotics (SAs) by horseradish peroxidase (HRP) is an eco-friendly and sustainable approach but with relatively low efficiency. In this study, we present bromide (Br−) enhances sulfamerazine (SMR) degradation in the process of HRP/H2O2. The removal rate of SMR is positively related to Br− concentration and increases over three times within 4 h as Br− concentration increases from 0 to 1 mM. The mechanism of promoting SMR degradation is mainly through oxidation and substitution by reactive bromine, which comes from the oxidation of bromide ions by HRP/H2O2. Moreover, structure and kinetics analysis of HRP confirm that Br− altered the hydrophobic structure of HRP and made it accessible to bind with SMR. Furthermore, eight degradation products are determined by ESI-Q-TOF-MS mass spectrometry. SMR transformation mainly involves two pathways: one way is hydrolysis and then breaking up of sulfonamide bond to generate small fragments, and another is demethylation and Smile rearrangement firstly, then through hydroxylation, SO2 extrusion, and bromine substitution to form other products. Bacteria growth experiments present the fact that neither the degradation products nor bromate formed in the process inhibited bacteria growth, indicating they have no obvious environmental risk. This study first reports Br− could accelerate the degradation of SMR by HRP and proposes the scheme of bromine species changes and SMR transformation pathways. This study not only develops a novel method to enhance the degradation of sulfonamides, but also provides a reference for the environmental risk assessment of sulfonamides.

Multiple roles of humic acid in the photogeneration of reactive bromine species using a chemical probe method

Photosensitization of natural organic matter (NOM) is an important natural source of reactive bromine species (RBrS) in the environment. Up to now, quantitative information about RBrS was mainly based on model sensitizers. Whether the behavior of model compounds could represent those of complex NOM remains unknown. In this study, we employed a chemical probe (3,5-dimethyl-1-H-pyrazole) to measure RBrS in humic acid (HA)-containing solutions and investigated their influential factors. The formation rate, decay rate constant, steady-state concentration, and lifetimes of RBrS were 3.87(±0.16) × 10−13 mol L−1·s−1, 1.99(±0.20) × 104 s−1, 2.04(±0.13) × 10−17 mol L−1, and 5.06(±1.05) × 10−5 s, respectively. Measured steady-state concentrations of RBrS were 3–5 orders of magnitude lower than those in model sensitizer system. Results showed that HA drove the RBrS generation, and about 0.12–0.70% of triplet-state HA (3HA*) would be transformed into RBrS. HA structures strongly affected this process. Phenolic-like groups suppressed the formation, while aromatic ketone-like moieties facilitated it. Last, HA also altered the transformation pathways. The contribution of ·OH dependent and direct oxidation pathways was almost equal, while the direct oxidation was predominant in the model system. Thus, careful consideration should be taken into photochemical formation of RBrS in NOM-involved solution, due to their complexity and multiple roles.

Influence of selected precipitating agents used for restoration of water reservoirs on the embryogenesis of pike (Esox lucius L.)

The aim of the study was to investigate the effect of iron coagulant (IC), aluminum coagulant (AC) and lanthanum modified bentonite (LMB) on the embryogenesis of pike. Physicochemical indicators of the water were determined according to the methods recommended by APHA (1999). The applied precipitating agents (IC, AC, LMB) at appropriate concentrations were sprayed on the surface of water in aquariums with the pike eggs placed on nets. The eggs were observed under a microscope, documenting their development using digital photography NIS Elements Br software. The number of fertilized eggs, embryo survival, and the percentage of malformed larvae were determined. The pike eggs and hatched larvae were recorded and measured.The percentage of fertilized eggs was found to be the highest in the control sample (LW) and in the IC sample (94% and 93.3%, respectively), 85.9% in the AC sample and 81.8% in the LMB sample. The pace of pike embryogenesis in the samples was identical – the embryos in both the control and other samples reached individual stages of embryonic development with an equal number of degree days (DD). The IC group hatched the earliest, and the control sample was the last to hatch (LW). In the control sample, the hatched larvae were the longest and had the lowest percentage of malformed individuals. The control sample also had the highest rate of embryo survival (85.9%), while the lowest was in the LMB sample (68.6%). These results indicate that the application of precipitating measures to improve water quality should not coincide with the periods of fish reproduction.

Simulation of Record Arctic Stratospheric Ozone Depletion in 2020

AbstractIn the Arctic winter/spring of 2019/2020, stratospheric temperatures were exceptionally low until early April and the polar vortex was very stable. As a consequence, significant chemical ozone depletion occurred in the Arctic polar vortex in spring 2020. Here, we present simulations using the Chemical Lagrangian Model of the Stratosphere that address the development of chlorine compounds and ozone in the Arctic stratosphere in 2020. The simulation reproduces relevant observations of ozone and chlorine compounds, as shown by comparisons with data from the Microwave Limb Sounder, Atmospheric Chemistry Experiment‐Fourier Transform Spectrometer, balloon‐borne ozone sondes, and the Ozone Monitoring Instrument. Although the concentration of chlorine and bromine compounds in the polar stratosphere has decreased by more than 10% compared to peak values around the year 2000, the meteorological conditions in winter/spring 2019/2020 caused unprecedented ozone depletion. The lowest simulated ozone mixing ratio was about 40 ppbv. Because extremely low ozone mixing ratios were reached in the lower polar stratosphere, chlorine deactivation into HCl occurred as is normally observed in the Antarctic polar vortex. The depletion in partial column ozone in the lower stratosphere (potential temperature from 350 to 600 K, corresponding to about 12–24 km) in the vortex core was calculated to reach 143 Dobson Units, which is more than the ozone loss in 2011 and 2016, the years which —until 2020— had seen the largest Arctic ozone depletion on record.

Electrochemical Generation of Hypervalent Bromine(III) Compounds.

In sharp contrast to hypervalent iodine(III) compounds, the isoelectronic bromine(III) counterparts have been little studied to date. This knowledge gap is mainly attributed to the difficult‐to‐control reactivity of λ 3‐bromanes as well as to their challenging preparation from the highly toxic and corrosive BrF3 precursor. In this context, we present a straightforward and scalable approach to chelation‐stabilized λ 3‐bromanes by anodic oxidation of parent aryl bromides possessing two coordinating hexafluoro‐2‐hydroxypropanyl substituents. A series of para‐substituted λ 3‐bromanes with remarkably high redox potentials spanning a range from 1.86 V to 2.60 V vs. Ag/AgNO3 was synthesized by the electrochemical method. We demonstrate that the intrinsic reactivity of the bench‐stable bromine(III) species can be unlocked by addition of a Lewis or a Brønsted acid. The synthetic utility of the λ 3‐bromane activation is exemplified by oxidative C−C, C−N, and C−O bond forming reactions.

Improvement in photocatalytic stability of AgBr under visible light through melt processing

Over the past decade, silver bromide (AgBr, mostly as plasmonic photocatalyst: Ag/AgBr) micro or nano crystals have been extensively studied due to its superior photocatalytic activity. However, AgBr and Ag/AgBr suffer from continuous formation of Ag0 in the photocatalytic process and the activity of the photocatalysts will be reduced rapidly, which is recognized as the bottleneck for further development and application of AgBr catalyst. In this study, we present the fabrication of melt-treated AgBr (AgBr-MT) under bromine atmosphere, which exhibits high photocatalytic activity. Surprisingly, AgBr-MT shows a giant improvement in photocatalytic stability compared to conventional powder catalysts, and the self-recovery phenomenon of AgBr was observed for the first time. The melt processing greatly reduces the unstable silver ions at the top and edge sites, and the surface reconstruction under bromine gas also contributes to the improvement of the stability of AgBr. Our findings may contribute to the development of efficient and stable silver halide-based materials and open a new perspective for this interesting material. The next research direction is to find a suitable support or prepare ultra-thin silver bromide film to further increase the effective area of AgBr.

AICAR decreases acute lung injury by phosphorylating AMPK and upregulating heme oxygenase-1.

We investigated the mechanisms by which N1-(β-d-ribofuranosyl)-5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), an activator of AMP-activated protein kinase (AMPK), decreases lung injury and mortality when administered to mice post exposure to bromine gas (Br2). We exposed male C57BL/6 mice and heme oxygenase-1 (HO-1)-deficient (HO-1-/-) and corresponding wild-type (WT) littermate mice to Br2 (600 ppm for 45 or 30 min, respectively) in environmental chambers and returned them to room air. AICAR was administered 6 h post exposure (10 mg·kg-1, intraperitoneal). We assessed survival, indices of lung injury, high mobility group box 1 (HMGB1) in the plasma, HO-1 levels in lung tissues and phosphorylation of AMPK and its upstream liver kinase B1 (LKB1). Rat alveolar type II epithelial (L2) cells and human club-like epithelial (H441) cells were also exposed to Br2 (100 ppm for 10 min). After 24 h we measured apoptosis and necrosis, AMPK and LKB1 phosphorylation, and HO-1 expression. There was a marked downregulation of phosphorylated AMPK and LKB1 in lung tissues and in L2 and H441 cells post exposure. AICAR increased survival in C57BL/6 but not in HO-1-/- mice. In WT mice, AICAR decreased lung injury and restored phosphorylated AMPK and phosphorylated LKB1 to control levels and increased HO-1 levels in both lung tissues and cells exposed to Br2. Treatment of L2 and H441 cells with small interfering RNAs against nuclear factor erythroid 2-related factor 2 or HO-1 abrogated the protective effects of AICAR. Our data indicate that the primary mechanism for the protective action of AICAR in toxic gas injury is the upregulation of lung HO-1 levels.

Baseline Study of Trace Element Concentrations in Sediments of the Intertidal Zone of Amazonian Oceanic Beaches

Analyzing the presence and quantifying trace elements is of paramount importance to understand natural environmental processes and monitor the degree of anthropogenic disturbance to mitigate impacts already caused. Here, we aimed to establish a baseline of the trace elements profile and concentrations in sandy sediments of intertidal areas of three Amazonian beaches (Brazil). For each beach, sediments were collected from three different sectors (south, center, and north) and five shoreline distance levels (from the high- to the low-water mark), totalizing 15 samples per beach. The concentration of the different trace elements (Mg, Al, P, S, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Rb, Sr, Y, Zr, Cd, Sn, I, Hg, and Pb) was determined by Total reflection X-ray Fluorescence spectrometry. Sediment was also characterized for its grain size, organic matter, and pH. To assess possible enrichment due to anthropogenic activities we compared trace element levels with the values for the Earth’s crust and calculated pollution indexes: geoaccumulation index (Igeo), ecological risk index (RI), contamination factor (CF), pollution load index (PLI), and sediment quality guideline (SQG), threshold effects level (TEL) and probable effects level (PEL). Individual trace metal concentrations did not vary significantly between beaches, sectors, or sample levels, evidencing a homogeneity of trace elements composition and concentrations across this environment. Igeo indicated 62.2% of the sampling stations uncontaminated, 20.0% from uncontaminated to moderately contaminated, and 4.44% (two sampling stations) strongly contaminated, the same two areas classified as high ecological risk by RI. Most of the sampling points presented low CF. Cadmium and Hg were the only elements that showed moderate to very high values of CF. According to the SQGs, 77.7 and 8.8% of the sampling points presented values above the moderate threshold effect level (SQG-TEL) and probable effect level (SQG-PEL), respectively. All points were classified as non-polluted according to the PLI. Our results show that the three beaches present safe levels of almost of the elements demonstrating the good state of preservation. Most of the indexes classified the sampling points as non-polluted, except for Cd and Hg in a few specific sampling points.

Time-dependent 3D simulations of tropospheric ozone depletion events in the Arctic spring using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem)

Abstract. Tropospheric bromine release and ozone depletion events (ODEs) as they commonly occur in the Arctic spring are studied using a regional model based on the open-source software package Weather Research and Forecasting model coupled with Chemistry (WRF-Chem). For this purpose, the MOZART (Model for Ozone and Related chemical Tracers)–MOSAIC (Model for Simulating Aerosol Interactions and Chemistry) chemical reaction mechanism is extended by bromine and chlorine reactions as well as an emission mechanism for reactive bromine via heterogeneous reactions on snow surfaces. The simulation domain covers an area of 5040 km×4960 km, centered north of Utqiaġvik (formerly Barrow), Alaska, and the time interval from February through May 2009. Several simulations for different strengths of the bromine emission are conducted and evaluated by comparison with in situ and ozone sonde measurements of ozone mixing ratios as well as by comparison with tropospheric BrO vertical column densities (VCDs) from the Global Ozone Monitoring Experiment-2 (GOME-2) satellite instrument. The base bromine emission scheme includes the direct emission of bromine due to bromide oxidation by ozone. Results of simulations with the base emission rate agree well with the observations; however, a simulation with 50 % faster emissions performs somewhat better. The bromine emission due to bromide oxidation by ozone is found to be important to provide an initial seed for the bromine explosion. Bromine release due to N2O5 was found to be important from February to mid March but irrelevant thereafter. A comparison of modeled BrO with in situ and multi-axis differential optical absorption spectroscopy (MAX-DOAS) data hints at missing bromine release and recycling mechanisms on land or near coasts. A consideration of halogen chemistry substantially improves the prediction of the ozone mixing ratio with respect to the observations. Meteorological nudging is essential for a good prediction of ODEs over the 3-month period.

Kα X-ray satellite spectra of Ge, As, Se and Br by photoionization

First and second order Kα X-ray satellites of the elements Ge, As, Se and Br were investigated by photon excitation. A wavelength dispersive spectrometer with LiF 420 crystal was employed. The energies and relative intensities of these X-ray satellites were measured. Their energy shifts and relative intensities with respect to the Kα diagram line are compared with theoretical estimates. Their dependence on atomic number is also examined.

The aug-cc-pVTZ-J basis set for the p-block fourth-row elements Ga, Ge, As, Se, and Br.

The aug-cc-pVTZ-J basis set family is extended to include the fourth-row p-block elements Ga, Ge, As, Se, and Br. We use the established approach outlined by Sauer and coworkers (J. Chem. Phys. 115, 1324 [2001], J. Chem. Phys. 133, 054308 [2010], J. Chem. Theory Comput. 7, 4070 [2011], and J. Chem. Theory Comput. 7, 4077 [2011]) where the completely uncontracted aug-cc-pVTZ basis set is saturated with tight s-, p-, d-, and f-functions to form the aug-cc-pVTZ-Juc basis set for the tested elements. The saturation is carried out on the simplest hydrides possible for the tested elements GaH, GeH4 , AsH3 , H2 Se, and HBr until an improvement is less than 0.01% for all s-, p-, and d-functions added. f-Functions are added to an improvement less than or equal to 1.0% due to the computational expense these functions add. The saturated aug-cc-pVTZ-Juc (26s16p12d5f) is then recontracted using the molecular orbital coefficients from self-consistent field calculations on the simple hydrides to improve computational efficiency. During contraction of the basis set, we observe that the linear hydrogen bromide molecule has a slower convergence than the other tested molecules which sets a limit on the accuracy obtained. All calculations with the contracted aug-cc-pVTZ-J [17s10p7d5f] gives results that are within 1.0% of the uncontracted results at considerable computational savings.

Trace elements in forensic human lung: A new approach to the diagnosis of seawater drowning. A preliminary study

The diagnosing of drowning remains one of the most challenging activities for the forensic pathologist. There is little information on the impact on the lung as a target organ in death by drowning. We aimed to investigate the concentration of trace elements in the lungs of people who had suffered different types of death to evaluate the discriminating ability of trace elements to identify seawater drowning (SWD). A total of 11 trace elements were analyzed by Inductively Coupled Plasma-Mass Spectrometry in 74 forensic cases. Sampler scanning electron microscopy and Energy Dispersive X-ray spectroscopy (EDX) were used to identify ultrastructural lung alterations. A Principal Component Analysis (PCA) of trace elements was carried out. The trace elements in SWD lungs were detected in the following order of concentration: Br˃Zn˃Sr˃Cr˃Cu˃As˃Pb˃Se˃Mn˃Ni˃Cd. Our results showed significantly higher concentrations of Br and Sr (P = 0.010 and P = 0.000) and significantly lower concentrations of Zn, Pb, Cu, Cd, and Se in SWD compared with other causes of death. After adjusting by confounder factors, Sr and Br remained as predictive independent factors for diagnosis of drowning (p = 0.042, in both cases). These results were confirmed by PCA, which revealed a wide separation between SWD and the rest of the causes of death. Our SWD cohort was characterized by high concentrations of the trace elements Br and Sr and low concentrations of Zn, Pb, Cu, Cd, and Se in lung tissue, while PCA showed its discriminatory capacity to identify death by seawater drowning. These findings, together with those obtained using other techniques, can be of great importance in the diagnosis of SWD.

Causes of Enhanced Bromine Levels in Alpine Ice Cores During the 20th Century: Implications for Bromine in the Free European Troposphere

AbstractTotal bromine (Br) was investigated in seasonally resolved alpine ice cores covering the 20th century. Results revealed increased Br concentrations in summer (from 0.7 ng g−1 in the late 1940s to 1.6 ng g−1 in the mid 1970s), followed by a slight decrease to 1.25 ng g−1 during the last decade of the 20th century. In winter, a more moderate increase was observed from before 1950 (0.35 ng g−1) to the 1970–2000 period (∼0.50 ng g−1). Measurements of lead suggest that ∼75% of the bromine increase in summer alpine ice between 1930–1950 and 1965–1985 was from bromine‐containing aerosol (PbBrCl) emitted during the combustion of leaded gasoline. This contribution decreased to ∼27% in 2000 following the large decrease of lead additive content in gasoline used in western Europe. Summer ice bromine concentrations, not related to PbBrCl aerosol (denoted Bry*), increased by 40% from the late 1940s to the 1990–2000 decade. In winter, the contribution of leaded‐gasoline aerosol to total bromine levels was weaker than in summer, with the winter bromine trend mainly caused by enhanced Bry* levels (∼40%) after 1950. These Bry* variations in glacial ice are discussed in terms of past atmospheric reactive bromine (Bry) changes in the European troposphere, including anthropogenic CH3Br emissions and transport from the stratosphere.