Co-Occurrence of Bromine and Iodine Species in US Drinking Water Sources That Can Impact Disinfection Byproduct Formation

Bromine and iodine species are precursors for forming disinfection byproducts in finished drinking waters. Our study incorporates spatial and temporal data to quantify concentrations of inorganic (bromide (Br-), iodide (I-), and iodate (IO3-)), organic, and total bromine (BrT) and iodine (IT) species from 286 drinking water sources and 7 wastewater effluents across the United States. Br- ranged from <5-7800 μg/L (median of 62 μg/L in surface water (SW) and 95 μg/L in groundwater (GW)). I- was detected in 41% of SW (1-72 μg/L, median = <1 μg/L) and 62% of GW (<1-250 μg/L, median = 3 μg/L) samples. The median Br-/I- ratio in SW and GW was 22 μg/μg and 16 μg/μg, respectively, in paired samples with detect Br- and I-. BrT existed primarily as Br-, while IT was present as I-, IO3-, and/or total organic iodine (TOI). Inorganic iodine species (I- and IO3-) were predominant in GW samples, accounting for 60-100% of IT; however, they contributed to only 20-50% of IT in SW samples. The unknown fraction of IT was attributed to TOI. In lakes, seasonal cycling of I-species was observed and was presumably due to algal productivity. Finally, Spearman Rank Correlation tests revealed a strong correlation between Br- and IT in SW (RBr-,IT = 0.83) following the log10 (Br-, μg/L) = 0.65 × log10 (IT, μg/L) - 0.17 relationship. Br- and I- in treated wastewater effluents (median Br- = 234 μg/L, median I- = 5 μg/L) were higher than drinking water sources.

Disinfection By-Products Formation from Chlor(am)ination of Algal Organic Matter of Chlorella sorokiniana

Eutrophication in water reservoirs releases algal organic matter (AOM), which is an important precursor of disinfection by-products (DBPs) formed during water treatment. Chlorella sorokiniana is a microalgae which flourishes under conditions of high light intensity and temperature, thus its prevalence in algal blooms is expected to increase with climate change. However, Chlorella sorokiniana AOM has not been previously investigated as a DBP precursor. In this context, this study evaluated the effect of AOM concentration, humic acid (HA), and pH on DBP formation from chlor(am)ination of AOM Chlorella sorokiniana. DBP yields determined by linear regression for trichloromethane (TCM) and chloral hydrate (CH) were 57.9 and 46.0 µg·mg DOC-1 in chlorination, while the TCM, CH, dichloroacetonitrile (DCAN), 1,1,1-trichloropropanone (1,1,1-TCP), and chloropicrin (CPN) concentrations were 33.6, 29.8, 16.7, 2.1, and 1.2 µg·mg DOC-1 in chloramination. Chloramination reduced the formation of TCM and CH but increased CPN, DCAN, and 1,1,1-TCP yields. AOM Chlorella sorokiniana showed a higher DBP formation than 9 of 11 algae species previously investigated in the literature. At basic pH, the concentration of TCM increased while the concentration of other DBP classes decreased. Bromide was effectively incorporated into the AOM structure and high values of bromine incorporation factor were found for THM (1.81-1.89) and HAN (1.32) at 1.5 mg Br·L-1. Empirical models predicted successfully the formation of THM and HAN (R2 > 0.86). The bromide concentration had more impact in the model on the DBP formation than AOM and HA. These results provide the first insights into the DBP formation from AOM chlor(am)ination of Chlorella sorokiniana.

Impacts of chloride-form anion exchange seawater regeneration performance

Seawater was investigated as an alternative regenerant source to conventional salt-imported brine solutions in an anion exchange process treating surficial Florida coastal groundwater for the removal of sulfate and organics. Bench-scale column testing revealed that filtered Sarasota Bay seawater efficiently regenerated the anion resin media; however, sulfate exchange capacity decreased by 8.42% compared with conventional 10% salt regeneration methods. Addition of 3% sodium chloride increased regeneration efficiency, reduced exchange capacity losses to 2.4% as compared to conventional 10% salt regeneration methods. Regeneration resulted in 2.13 mg/L of bromide leakage; however, addition of 3% sodium chloride to seawater reduced bromide leakage to 1.25 mg/L. A correlation between bromide exchange and the regenerant chloride-to-bromide molar ratio (CBMR) was observed, yielding less bromide exchange at higher CBMRs. Bromide adsorption followed pseudo 2nd order kinetics and chemisorption was the rate controlling step. Increasing the CBMR of the regenerant was found to shift adsorption behaviour, allowing intra-particle diffusion to occur sooner. Bromide equilibrium appeared to follow a logarithmic decay as the CBMR of the regenerant increased. Intra-particle and film diffusion mechanisms were evaluated that indicated the presence of diffusion-based processes and more than one rate controlling step. An empirical function was derived to approximate bromide equilibrium adsorption in relation to a regenerant's CBMR. Seawater as a regenerant when enhanced with sodium chloride shows promise as an anion exchange regenerant; additionally, classification of a seawater regenerant's CBMR can provide insight into the kinetic and equilibrium relationships of bromide exchange.

Overlooked Contribution of the Indole Moiety to the Formation of Haloacetonitrile Disinfection Byproducts

Haloacetonitriles (HANs) are a group of disinfection byproducts with high toxicity and frequent occurrence. Past studies have focused on the free amine groups, especially those in amino acids, as HAN precursors. This study reports, for the first time, that the indole moiety such as that in the tryptophan side chain is also a potent precursor for the most common HANs dichloroacetonitrile, bromochloroacetonitrile, and dibromoacetonitrile. 3-Indolepropionic acid, differing from tryptophan only in the absence of the free amine group, formed HANs at levels 57-76% of those by tryptophan at a halogen/nitrogen molar ratio of 10. Experiments with tryptophan-(amino-¹⁵N) showed that the indole contributed to 28-51% of the HANs formed by tryptophan. At low oxidant excess (e.g., halogen/precursor = 5), 3-indolepropionic acid even formed more HANs than Trp by 3.5-, 2.5-, and 1.8-fold during free chlorination, free bromination, and chlorination in the presence of bromide (0.6 mg/L), respectively. Indole's HAN formation pathway was investigated by exploring the chlorination/bromination products of 3-indolepropionic acid using liquid chromatography-orbitrap high-resolution mass spectrometry. A total of 22 intermediates were detected, including pyrrole ring-opening products with an N-formyl group, 2-substituted anilines with different hydroxyl/halogen substitutions, and an intermediate with a postulated non-aromatic ring structure.

Halogenoderma: A Case Report and Review of the Literature

Halogenoderma (HD) is an uncommon dermatosis that develops following exposure to halogens such as iodide and bromide, referred to as iododerma and bromoderma, respectively. Here, we report the case of a 40-year-old male who presented with a three-week history of slightly itchy progressive skin lesions associated with low-grade fever and malaise. The patient had a history of using food supplements containing iodide and bromide for four months prior to the appearance of skin rashes. Skin examination revealed multiple crusted papules and nodules scattered on his face, neck, and trunk. A skin biopsy was taken from the lesions. The epidermis showed crustation, exocytosis of neutrophils, and multiple intraepidermal abscesses. The dermis showed heavy cellular infiltrates composed mainly of neutrophils. The skin lesions disappeared completely after the cessation of food supplements, along with the use of topical corticosteroids for a few weeks.

Fabrication of Polyaniline/Graphene Oxide Nanosheet@ Tea Waste Granules Adsorbent for Groundwater Purification

The reuse and separation of nanomaterials from an aquatic solution is always challenging and may cause nanotoxicity if not separated completely. Nanomaterial immobilization on the surface of a macro-size material could be an effective approach to developing an efficient composite for groundwater purification. Herein, polyaniline and graphene oxide nanosheet immobilized granular tea waste (PANI/GO@GTW) has been synthesized to remove the anionic and cationic contaminants from groundwater. The synthesized materials were characterized by SEM, XRD, XPS, and FTIR spectroscopies. The optimization of experimental conditions was tested for bromide (Br−) removal from synthetic water. The results revealed that Br− adsorption behavior onto the synthesized materials was as follows: PANI/GO < PANI/GTW < PANI < PANI/GO@GTW. The optimum removal of Br− ions was observed at pH 3 with 90 min of saturation time. Br− adsorption onto PANI/GO@GTW followed the pseudo-first-order kinetic and Langmuir isotherm model, and electrostatic interaction was involved in the adsorption process. The optimum adsorption of Br− onto PANI/GO@GTW was found to be 26.80 m/g. The application of PANI/GO@GTW on real groundwater treatment demonstrated the effective removal of anion pollutants such as F−, Cl−, Br−, NO3−, and PO43−. This study revealed that PANI/GO@GTW successfully reduced Br− concentrations in synthetic and real groundwater and can be used for large-scale applications.

Ultrasound process-enhanced removal of the toxic disinfection by-product bromate from water by aluminum: A comparative study

As bromate removal and reduction can be also achieved using metals, aluminum (Al) appears as the most promising one for reduction of bromate because Al is abundant element and exhibits a high reduction power. Reactions between bromate and Al shall be even enhanced through ultrasound (US) process because US can facilitate mass transfer on liquid/solid interfaces and clean surfaces via generating microscale turbulence to facilitate reactions. Therefore, the aim of this study is for the first time to investigate the effect of US on bromate removal by Al metal. Specifically, Al particle would be treated by HCl to afford HCl-treated Al (HCTAL), which is capable of removing bromate and even reducing it to bromide. Such a mechanism is also validated by density function theory calculation through determining adsorption energy as -152.8 kJ/mole, and oxygen atoms of bromate would be extracted and reacted with Al atoms, releasing bromide ion. US not only facilitated bromate removal by further increasing removal capacity under the acidic condition but also suppressed the inhibitive effect from basicity at relatively high pH. The spent HCTAL could still remove bromate and convert it to bromide after regeneration. These features indicate that US considerably enhances bromate removal by Al. PRACTITIONER POINTS: Bromate removed by Al is elucidated by DFT calculation with E_absorption  = -152.8 kJ/mole. Oxygen atoms of bromate are extracted and reacted with Al atoms, releasing bromide ion. A higher power of ultrasound would substantially enhance bromate removal efficiency. Ultrasound also suppresses the inhibitive effect from basicity at relatively high pH. With ultrasound, the interference of co-existing anions on bromate removal is lessened.

Electrooxidation of coragen-contaminated wastewater using graphite electrodes and sorbent nano-hydroxyapatite

The degradation of coragen (C₁₈H₁₄N₅O₂BrCl₂) was tested by the electrooxidation process using graphite electrodes. Further, the advantage of nano-hydroxyapatite (n-Hap), as a cost-effective nano sorbent, in the removal of bromide from coragen was examined. Three different variables such as initial pH, electrolysis time and the current density were used to analyse the effects of the electrolytic process on the degradation of coragen. During electrolysis, under various stages, the parameters such as chemical oxygen demand (COD), chloride and bromide were analysed. The maximum COD, chloride and bromide removal efficiency of 96%, 50% and 99%, respectively, at pH 5, the maximum current density of 7.5 mA cm^-2 and 120 min electrolysis time were achieved. Based on the final output of this study, it can be concluded that the electrolysis process can effectively reduce COD, chloride and bromide from coragen in an aqueous medium. Further, the degradation efficiency of the coragen was confirmed through different analyses such as UV spectra, Fourier transform infrared spectroscopy and gas chromotography-mass spectrometry analyses.

Impact of Tetrabutylammonium on the Oxidation of Bromide by Ozone

The reaction of ozone with sea-salt derived bromide is relevant for marine boundary layer atmospheric chemistry. The oxidation of bromide by ozone is enhanced at aqueous interfaces. Ocean surface water and sea spray aerosol are enriched in organic compounds, which may also have a significant effect on this reaction at the interface. Here, we assess the surface propensity of cationic tetrabutylammonium at the aqueous liquid-vapor interface by liquid microjet X-ray photoelectron spectroscopy (XPS) and the effect of this surfactant on ozone uptake to aqueous bromide solutions. The results clearly indicate that the positively charged nitrogen group in tetrabutylammonium (TBA), along with its surface activity, leads to an enhanced interfacial concentration of both bromide and the bromide ozonide reaction intermediate. In parallel, off-line kinetic experiments for the same system demonstrate a strongly enhanced ozone loss rate in the presence of TBA, which is attributed to an enhanced surface reaction rate. We used liquid jet XPS to obtain detailed chemical composition information from the aqueous-solution-vapor interface of mixed aqueous solutions containing bromide or bromide and chloride with and without TBA surfactant. Core level spectra of Br 3d, C 1s, Cl 2p, N 1s, and O 1s were used for this comparison. A model was developed to account for the attenuation of photoelectrons by the carbon-rich layer established by the TBA surfactant. We observed that the interfacial density of bromide is increased by an order of magnitude in solutions with TBA. The salting-out of TBA in the presence of 0.55 M sodium chloride is apparent. The increased interfacial bromide density can be rationalized by the association constants for bromide and chloride to form ion-pairs with TBA. Still, the interfacial reactivity is not increasing simply proportionally with the increasing interfacial bromide concentration in response to the presence of TBA. The steady state concentration of the bromide ozonide intermediate increases by a smaller degree, and the lifetime of the intermediate is 1 order of magnitude longer in the presence of TBA. Thus, the influence of cationic surfactants on the reactivity of bromide depends on the details of the complex environment at the interface.

Crystal structure of di-aqua-(3,14-diethyl-2,6,13,17-tetra-aza-tri-cyclo-[16.4.0.07,12]docosa-ne)copper(II) (3,14-diethyl-2,6,13,17-tetra-aza-tri-cyclo[16.4.0.07,12]docosa-ne)copper(II) tetra-bromide dihydrate, [Cu(C22H44N4)(H2O)2][Cu(C22H44N4)]Br4·2H2O

The crystal structure of the new double CuII complex salt, [Cu(L)(H2O)2][Cu(L)]Br4·2H2O (L = 3,14-diethyl-2,6,13,17-tetra-aza-tri-cyclo-[16.4.0.07,12]docosane, C22H44N4) has been determined using synchrotron radiation. The asymmetric unit contains one half of a [Cu(L)(H2O)2]2+ cation, one half of a [Cu(L)]2+ cation (both completed by crystallographic inversion symmetry), two bromide anions and one water solvent mol-ecule. The CuII atom in the first complex exists in a tetra-gonally distorted octa-hedral environment with the four N atoms of the macrocyclic ligand in equatorial and two aqua ligands in axial positions, whereas the CuII atom in the second complex exists in a square-planar environment defined by the four nitro-gen atoms of the macrocyclic ligand. The two macrocyclic rings adopt the most stable trans-III configuration with normal Cu-N bond lengths from 2.016 (3) to 2.055 (3) Å and an axial Cu-O bond length of 2.658 (4) Å. The crystal structure is stabilized by inter-molecular hydrogen bonds involving the macrocycle N-H or C-H groups and the O-H groups of water mol-ecules as donor groups, and the O atoms of water mol-ecules and bromide anions as acceptor groups, giving rise to a one-dimensional network extending parallel to [100].

Intrinsic Dynamic and Static Nature of Halogen Bonding in Neutral Polybromine Clusters, with the Structural Feature Elucidated by QTAIM Dual-Functional Analysis and MO Calculations

The intrinsic dynamic and static nature of noncovalent Br-∗-Br interactions in neutral polybromine clusters is elucidated for Br4-Br12, applying QTAIM dual-functional analysis (QTAIM-DFA). The asterisk (∗) emphasizes the existence of the bond critical point (BCP) on the interaction in question. Data from the fully optimized structures correspond to the static nature of the interactions. The intrinsic dynamic nature originates from those of the perturbed structures generated using the coordinates derived from the compliance constants for the interactions and the fully optimized structures. The noncovalent Br-∗-Br interactions in the L-shaped clusters of the Cs symmetry are predicted to have the typical hydrogen bond nature without covalency, although the first ones in the sequences have the vdW nature. The L-shaped clusters are stabilized by the n(Br)→σ*(Br-Br) interactions. The compliance constants for the corresponding noncovalent interactions are strongly correlated to the E(2) values based on NBO. Indeed, the MO energies seem not to contribute to stabilizing Br4 (C2h) and Br4 (D2d), but the core potentials stabilize them, relative to the case of 2Br2; this is possibly due to the reduced nuclear-electron distances, on average, for the dimers.

Stripping and Plating a Magnesium Metal Anode in Bromide-Based Non-Nucleophilic Electrolytes

A non-nucleophilic Hauser base hexamethyldisilazide (HMDS) magnesium electrolyte possesses inherent properties required for a magnesium-sulfur battery. However, the development of full cell batteries using HMDSCl-based electrolytes is still hampered by a low coulombic efficiency. A new electrolyte formulation of non-nucleophilic HMDS magnesium containing bromide as a halide instead of chloride was obtained through a simple and straightforward synthesis route. The electrochemistry of magnesium was investigated through plating and stripping in three different HMDSBr-based electrolytes: Mg(HMDS)Br, Mg(HMDS)Br-BEt₃ , and Mg(HMDS)Br-AlEt₃ dissolved in tetrahydrofuran. The different magnesium species present in the electrolytes were determined using NMR. Weak electron-withdrawing Lewis acids, BEt₃ and AlEt₃ were used intentionally and their impact was investigated. Contrary to expectation, the substitution of chloride by bromide does not drastically narrow the electrochemical stability window. HMDSBr-based electrolytes demonstrated long-term (1000 cycles) stable reversibility and highly efficient (≈99 %) magnesium plating/tripping without a high ratio of bromide compared with the MgHMDSCl-based electrolytes. The aprotic electrolyte shows comparatively high anodic stability (≈2.4 V vs. Mg/Mg²⁺ ) and high ionic conductivity of 1.16 mS cm^-1 at room temperature. Plating of magnesium with low overpotential (<188 mV) revealed a morphology dependence on the electrolyte type with a shiny metallic homogenous layer, suggesting a rational balance between the nucleation and growth process in HMDSBr-based electrolytes.

Effects of Pre-Oxidation on Haloacetonitrile and Trichloronitromethane Formation during Subsequent Chlorination of Nitrogenous Organic Compounds

The reaction between organic matter and disinfectants leads to the formation of disinfection byproducts (DBPs) in drinking water. With the improvement of detection technology and in-depth research, more than 1000 kinds of DBPs have been detected in drinking water. Nitrogenous DBPs (N-DBPs) are more genotoxic and cytotoxic than the regulated DBPs. The main methods are enhanced coagulation, pretreatment, and depth technologies which based are on conventional technology. Amino acids (AAs) are widely found in surface waters and play an important role by providing precursors from which toxic nitrogenous disinfection by-products (N-DBPs) are generated in chlorinated drinking water. The formation of N-DBPs, including dichloroacetonitrile, trichloroacetonitrile, and trichloronitromethane (TCNM), was investigated by analyzing chlorinated water using ozone (OZ), permanganate (PM), and ferrate (Fe(VI)) pre-oxidation processes. This paper has considered the control of pre-oxidation over N-DBPs formation of AAs, OZ, PM, and Fe(VI) pre-oxidation reduced the haloacetonitrile formation in the downstream chlorination. PM pre-oxidation decreased the TCNM formation during the subsequent chlorination, while Fe(VI) pre-oxidation had no significant influence on the TCNM formation, and OZ pre-oxidation increased the formation. OZ pre-oxidation formed the lowest degree of bromine substitution during subsequent chlorination of aspartic acid in the presence of bromide. Among the three oxidants, PM pre-oxidation was expected to be the best choice for reducing the estimated genotoxicity and cytotoxicity of the sum of the measured haloacetonitriles (HANs) and TCNM without bromide. Fe(VI) pre-oxidation had the best performance in the presence of bromide.

Advances in Treatment of Brominated Hydrocarbons by Heterogeneous Catalytic Ozonation and Bromate Minimization

The formation of carcinogenic bromate ions is a constraint when ozone is used for the remediation of water containing brominated organic materials. With its strong oxidizing ability, ozone rapidly transforms bromide in aqueous media to bromate, through a series of reactions involving hydroxyl radicals. Several strategies, such as limiting the ozone concentration, maintaining pH < 6, or the use of ammonia or hydrogen peroxide were explored to minimize bromate generation. However, most of the above strategies had a negative effect on the ozonation efficiency. The advanced oxidation processes, using catalysts together with ozone, have proven to be a promising technology for the degradation of pollutants in wastewater, but very few studies have been conducted to find ways to minimize bromate formation during this approach. The proposed article, therefore, presents a comprehensive review on recent advances in bromate reduction in water by catalytic ozonation and proposes reaction mechanisms associated with the catalytic process. The main aim is to highlight any gaps in the reported studies, thus creating a platform for future research and a quest to find environment friendly and efficacious catalysts for minimizing bromate formation in aqueous media during ozonation of brominated organic compounds.

Determining conventional and unconventional oil and gas well brines in natural samples I: Anion analysis with ion chromatography

Unconventional natural gas extraction by hydraulic fracturing requires millions of gallons of water and generates flowback water, produced water and recycled fluids of varying chemical composition. Ion chromatography (IC) is a relatively low cost and efficient means to determine the anionic composition, however, the wide range in anionic content of these fluids poses a challenge to analytical methods developed for "natural" waters. We report here that the combination of UV and conductivity detectors increased detection sensitivity (e.g., 10-50 ppb) and expanded the number of anions detectable in a single sample run. Samples from four unconventional shale gas wells, two impoundments, nine conventional oil wells, two freshwater streams and mine drainage samples were analyzed in this study. All produced water samples and impoundment samples had high chloride (17,500-103,000 mg L^-1, 93,900 to 134,000 mg L^-1, 27,700 and 30,700 mg L^-1), bromide (178-996 mg L^-1, 183-439 mg L^-1, 230 and 260 mg L^-1) and conductivity (38,500-160,000 μS/cm³, 95,300 to 183,000 μS/cm³, 61,500 and 103,000 μS/cm³), respectively, relative to mine drainage and freshwater stream samples. Molar ratio analysis using Cl^-/Br^- to Cl^- and SO₄^2-/Cl^- to Br^- revealed significant differences between the samples, providing a simple means for distinguishing water impacted by different sources of contamination.

Re-assessing ICR GAC Treatment Study Database: Effect of Bromide on DBP Formation

While granular active carbon (GAC) can effectively remove disinfection byproduct (DBP) precursors, its use has raised concerns over increased formation of some brominated DBP species in treated water following postchlorination, especially for waters with high bromide concentrations. The Information Collection Rule Treatment Study Database contains results of the most extensive GAC studies ever conducted nationwide. Data were analyzed to assess the extent of DBP speciation changes and overall reduction of brominated DBPs by GAC to gain new insights of the bromide effect. Results showed that formation of three brominated trihalomethanes (collectively, Br-THM3) varied greatly depending on TOC removal and bromide concentrations. Low TOC concentrations in GAC effluents resulted in greatly reduced Br-THM3 formation, except for a few cases where Br-THM3 formation increased. GAC followed by chloramination were likely to better control Br-THM3 formation for waters with high TOC and high bromide. Lastly, the chlorine demand reduction by GAC was quantified.

Bromide alleviates fatty acid-induced lipid accumulation in mouse primary hepatocytes through the activation of PPARα signals

Increased plasma free fatty acids (FFAs) and liver triglyceride (TG) accumulations have been implicated in the pathogenesis of hepatic steatosis. On the other hand, trace elements function as essential cofactors that are involved in various biochemical processes in mammals, including metabolic homeostasis. Notably, clinical and animal studies suggest that the plasma levels of bromide negatively correlate with those of TG, total cholesterol (TC) and high‐density lipoprotein‐cholesterol (HDL‐C). However, the effect of bromide on lipid accumulation and the direct molecular target responsible for its action remains unknown. Oil red O (ORO) and Nile red staining were used to detect the effect of bromide on lipid accumulation in mouse primary hepatocytes (PHs) treated with different doses of sodium bromide (NaBr) in the presence of FFAs (0.4 mM oleate/palmitic acid 1:1). Spectrophotometric and fluorometric analyses were performed to assess cellular TG concentrations and rates of fatty acid oxidation (FAO), respectively, in mouse PHs. We found that bromide decreased FFA‐induced lipid accumulation and increased FFA‐inhibited oxygen consumptions in mouse PHs in a dose‐dependent manner via activation of PPARα. Mechanical studies demonstrated that bromide decreased the phosphorylation levels of JNK. More importantly, the PPARα‐specific inhibitor GW6471 partially abolished the beneficial effects of bromide on mouse PHs. Bromide alleviates FFA‐induced excessive lipid storage and increases rates of FAO through the activation of PPARα/JNK signals in mouse PHs. Therefore, bromide may serve as a novel drug in the treatment of hepatic steatosis.

Three-Dimensional Calibration for Routine Analyses of Bromide and Nitrate Ions as Indicators of Groundwater Quality in Coastal Territories

Nitrate and bromide ions are generally considered indicators of anthropogenic pollution and seawater intrusion, respectively, in the groundwater of coastal territories. The analysis of these species is generally carried out with routine chromatographic analyses which generally afford partially merged or poorly resolved peaks. In the present paper a simple method for the correct evaluation of their concentration in water is reported. This method does not imply utilization of other instruments or technologies, only the mathematical elaboration of the data obtained from routine analysis of standard solutions containing the two species. Standard binary solutions of nitrate and bromide ions at different concentrations, ranging between 0.1 and 2 mM, were analyzed by means of ion chromatography. Splitting two partially merged chromatographic peaks and considering each resulting area as originating from a single species produces "measured" concentration values which differ from the nominal ones. Such a procedure generates errors (one per species) which can be written as a function of the above mentioned "measured" concentrations and which can be graphically represented by means of a surface in a three-dimensional (3D) space. In this way, "measured" concentrations of bromide and nitrate ions can be corrected by calculating the errors generated under the experimental conditions at which the chromatographic separation is performed. Notably, this is analogous with the two-dimensional (2D) calibration normally carried out for analytical purposes. Indeed, both methods allow estimation of the unknown concentration of species in solution by correlating the instrumental response with the concentration of standard solutions.

Factors affecting N-nitrosodimethylamine formation from poly(diallyldimethyl-ammonium chloride) degradation during chloramination

Poly(diallyldimethylammonium chloride) (polyDADMAC) has been shown to be an important precursor of the probable human carcinogen N-nitrosodimethylamine (NDMA) when in contact with chloramine. In this study, we conducted an orthogonal experiment design to evaluate the effects of pH values, ammonia, bromide, natural organic matter (NOM) and monochloramine dosages on the formation of NDMA from polyDADMAC during chloramination. Meanwhile, single-factor experiments of pH, bromide and NOM prove the results of orthogonal experiment. The results supported that pH was the most critical factor affecting NDMA formation from polyDADMAC during chloramination, and the highest NDMA formation from polyDADMAC occurred at pH near 7 due to released DMA from polyDADMAC degradation and the critical importance of low concentrations of dichloramine in water. In the presence of excess bromide, the NDMA formation was enhanced significantly at all different pH values owing to bromochloramine, which has higher electronegativity of the brominated nitrogen atom than monochloramine or dichloramine. The NDMA formation from polyDADMAC in the presence of NOM was 41.7% lower than NDMA formation in the absence of NOM. The overwhelming majority of NDMA formation from polyDADMAC under simulated conditions was lower than the current advisory levels (i.e. 9 ng l-1 in Ontario, 10 ng l-1 in California).

Potentiometric Sensors for Iodide and Bromide Based on Pt(II)-Porphyrin

Pt(II) 5,10,15,20-tetra(4-methoxy-phenyl)-porphyrin (PtTMeOPP) was used in the construction of new ion-selective sensors. The potentiometric response characteristics (slope and selectivity) of iodide and bromide-selective electrodes based on (PtTMeOPP) metalloporphyrin in o-nitrophenyloctylether (NPOE), dioctylphtalate (DOP) and dioctylsebacate (DOS) plasticized poly(vinyl chloride) membranes are compared. The best results were obtained for the membranes plasticized with DOP and NPOE. The sensors have linear responses with near-Nernstian slopes toward bromide and iodide ions and good selectivity. The membrane plasticized with NPOE was electrochemically characterized using the EIS method to determine its water absorption and the diffusion coefficient into the membrane.

HBr-DMPU: The First Aprotic Organic Solution of Hydrogen Bromide

HBr and DMPU (1,3-dimethyl-3,4,5,6-tetrahydro-2-pyrimidinone) form a room-temperature-stable complex that provides a mild, effective, and selective hydrobrominating reagent toward alkynes, alkenes, and allenes. HBr-DMPU could also replace other halogenating reagents in the halo-Prins reaction, ether cleavage, and deoxy-bromination reactions.

Crystal structures of di-bromido-{N-[(pyridin-2-yl-κN)methyl-idene]picolinohydrazide-κ2N',O}cadmium methanol monosolvate and di-iodido{N-[(pyridin-2-yl-κN)methyl-idene]picolinohydrazide-κ2N',O}cadmium

The title compounds, [CdBr2(C12H10N4O)]·CH3OH, (I), and [CdI2(C12H10N4O)], (II), are cadmium bromide and cadmium iodide complexes of the ligand (E)-N'-(pyridin-2-yl-methyl-ene)picolinohydrazide. Complex (I) crystallizes as the methanol monosolvate. In both compounds, the Cd2+ cation is ligated by one O atom and two N atoms of the tridentate ligand, and by two bromide anions forming a Br2N2O penta-coordination sphere for (I), and by two iodide anions forming an I2N2O penta-coordination sphere for (II), both with a distorted square-pyramidal geometry. In the crystal of complex (I), mol-ecules are linked by pairs of N-H⋯O and O-H⋯Br hydrogen bonds, involving the solvent mol-ecule, forming dimeric units, which are linked by C-H⋯Br hydrogen bonds forming layers parallel to (101). In the crystal of complex (II), mol-ecules are linked by N-H⋯I hydrogen bonds, forming chains propagating along [010]. In complex (II), measured at room temperature, the two iodide anions are each disordered over two sites; the refined occupancy ratio is 0.75 (2):0.25 (2).

Two new isostructural mercury(II) complexes involving the N-heterocyclic 1-[(benzotriazol-1-yl)methyl]-1H-1,3-imidazole ligand: syntheses, structures and properties

The unsymmetrical N-heterocyclic ligand 1-[(benzotriazol-1-yl)methyl]-1H-1,3-imidazole (bmi) has three potential N-atom donors and can act in monodentate or bridging coordination modes in the construction of complexes. In addition, the bmi ligand can adopt different coordination conformations, resulting in complexes with different structures due to the presence of the flexible methylene spacer. Two new complexes, namely bis{1-[(benzotriazol-1-yl)methyl]-1H-1,3-imidazole-κN³}dibromidomercury(II), [HgBr₂(C₁₀H₉N₅)₂], and bis{1-[(benzotriazol-1-yl)methyl]-1H-1,3-imidazole-κN³}diiodidomercury(II), [HgI₂(C₁₀H₉N₅)₂], have been synthesized through the self-assembly of bmi with HgBr₂ or HgI₂. Single-crystal X-ray diffraction shows that both complexes are mononuclear structures, in which the bmi ligands coordinate to the Hg^II ions in monodentate modes. In the solid state, both complexes display three-dimensional networks formed by a combination of hydrogen bonds and π-π interactions. The IR spectra and PXRD patterns of both complexes have also been recorded.

Genotoxicity evaluation of ionic liquid 1-octyl-3-methylimidazolium bromide in freshwater planarian Dugesia japonica using RAPD assay

The randomly amplified polymorphic DNA (RAPD) assay has been used to detect DNA alternation and mutation recently. However, the effectiveness of this method in detecting DNA damage in planarians, a model organism for assessing the toxicity of environmental pollutants is unknown. In the present study, RAPD assay was used to detect the DNA damage in planarians treated by the ionic liquid 1-octyl-3-methylimidazolium bromide ([C₈mim]Br) for the first time. Among the 20 test RAPD primers, 13 primers with 60-70% GC content produced unique polymorphic band profiles. A total of 60 bands were observed in the untreated control planarians. In comparison with the control group, the [C₈mim]Br-treated groups displayed differences in RAPD patterns in the band intensity, disappearance of normal bands and appearance of new bands. The variation of RAPD profiles showed both concentration- and time-effect relationships. Meanwhile, the genomic template stability (GTS) of treated planarians decreased and exhibited negative correlation to the exposure concentration and time of [C₈mim]Br. Our results suggested that [C₈mim]Br had genotoxic effects on planarians, and this DNA damage analysis would lay the foundation for further elucidating the toxicity mechanisms of ionic liquids on planarians. Furthermore, RAPD analysis was proved to be a highly sensitive method for the detection of DNA damage induced by environmental pollutants like toxic chemicals on planarians.

Syntheses, structures and properties of two new isostructural zinc(II) complexes based on 1-[(benzotriazol-1-yl)methyl]-1H-imidazole

Due to their strong coordination ability and the diversities of their coordination modes, N-heterocyclic organic compounds are used extensively as ligands for the construction of complexes with fascinating structures and potential applications in many fields. Two new complexes, namely bis{1-[(benzotriazol-1-yl)methyl]-1H-imidazole-κN³}dibromidozinc(II), [ZnBr₂(C₁₀H₉N₅)₂], (I), and bis{1-[(benzotriazol-1-yl)methyl]-1H-imidazole-κN³}diiodidozinc(II), [ZnI₂(C₁₀H₉N₅)₂], (II), have been synthesized by reaction of the unsymmetrical N-heterocyclic ligand 1-[(benzotriazol-1-yl)methyl]-1H-imidazole (bmi) with Zn(acetate)₂ in the presence of KBr or KI. Single-crystal X-ray diffraction analysis shows that both complexes exhibit a mononuclear structure, in which the bmi ligands coordinate to the central metal ion in a monodentate mode. In the solid state, both complexes possess a three-dimensional network formed by hydrogen bonds and π-π interactions. In addition, the IR spectroscopic properties, PXRD patterns and fluorescence properties of both complexes have been investigated.

Washoff of Residual Photosystem II Herbicides from Sugar Cane Trash under a Rainfall Simulator

Herbicides are often applied to crop residues, but their fate has not been well studied. We measured herbicide washoff from sugar cane trash during simulated rainfall, at 1, 8, and 40 days after spraying (DAS), to provide insight into herbicide fate and for use in modeling. Herbicides included are commonly used in the sugar industry, either in Australia or in Brazil. Concentrations of all herbicides and applied Br tracer in washoff declined exponentially over time. The rate of washoff during rainfall declined with increasing DAS. Cumulative washoff as a function of rainfall was similar for most herbicides, although the most soluble herbicides did have more rapid washoff. Some but not all herbicides became more resistant to washoff with increasing DAS. Of the total mass washed off, 80% washed off in the first 30 mm (∼40 min) of rainfall for most herbicides. Little herbicide remained on the trash after rainfall, implying nearly complete washoff.

Crystal structure of 2-bromo-3-di-methyl-amino-N,N,N',N',4-penta-methyl-4-(tri-methyl-sil-yloxy)pent-2-eneamidinium bromide

The reaction of the ortho-amide 1,1,1-tris-(di-methyl-amino)-4-methyl-4-(tri-methyl-sil-yloxy)pent-2-yne with bromine in benzene, yields the title salt, C15H33BrN3OSi(+)·Br(-). The C-N bond lengths in the amidinium unit are 1.319 (6) and 1.333 (6) Å, indicating double-bond character, pointing towards charge delocalization within the NCN plane. The C-Br bond length of 1.926 (5) Å is characteristic for a C-Br single bond. Additionally, there is a bromine-bromine inter-action [3.229 (3) Å] present involving the anion and cation. In the crystal, weak C-H⋯Br inter-actions between the methyl H atoms of the cation and the bromide ions are present.

Crystal structure of N-[3-(di-methyl-aza-nium-yl)prop-yl]-N',N',N'',N''-tetra-methyl-N-(N,N,N',N'-tetra-methyl-form-am-id-in-ium-yl)-guanidinium dibromide hydroxide monohydrate

The asymmetric unit of the title hydrated salt, C15H37N6 (3+)·2Br(-)·OH(-)·H2O, contains one cation, three partial-occupancy bromide ions, one hydroxide ion and one water mol-ecule. Refinement of the site-occupancy factors of the three disordered bromide ions converges with occupancies 0.701 (2), 0.831 (2) and 0.456 (2) summing to approximately two bromide ions per formula unit. The structure was refined as a two-component inversion twin with volume fractions 0.109 (8):0.891 (8) for the two domains. The central C3N unit of the bis-amidinium ion is linked to the aliphatic propyl chain by a C-N single bond. The other two bonds in this unit have double-bond character as have the four C-N bonds to the outer NMe2 groups. In contrast, the three C-N bonds to the central N atom of the (di-methyl-aza-nium-yl)propyl group have single-bond character. Delocalization of the two positive charges occurs in the N/C/N and C/N/C planes, while the third positive charge is localized on the di-methyl-ammonium group. The crystal structure is stabilized by O-H⋯O, N-H⋯Br, O-H⋯Br and C-H⋯Br hydrogen bonds, forming a three-dimensional network.

Ring Opening Reactions through C-O Bond Cleavage Uniquely Adding Chemical Functionality to Boron Subphthalocyanine

We are reporting the unexpected reaction between bromo-boron subphthalocyanine (Br-BsubPc) and THF, 1,4-dioxane or γ-butyrolactone that results in the ring opening of the solvent and its addition into the BsubPc moiety. Under heating, the endocyclic C-O bond of the solvent is cleaved and the corresponding bromoalkoxy-BsubPc derivative is obtained. These novel alkoxy-BsubPc derivatives have remaining alkyl-bromides suitable for further functionalization. The alkoxy-BsubPcs maintain the characteristic strongly absorption in visible spectrum and their fluorescence quantum yields.

Crystal structure of 4-amino-1-(4-methyl-benz-yl)pyridinium bromide

The title mol­ecular salt, C₁₃H₁₅N₂⁺·Br⁻, crystallized with two independent ion pairs (A and B) in the asymmetric unit. In the cations, the planes of the pyridine and benzene rings are inclined to one another by 79.32 (8) and 82.30 (10)° in ion pairs A and B, respectively. In the crystal, the anions and cations are connected by N—H⋯Br hydrogen bonds, forming a centrosymmetric tetra­mer-like unit enclosing an R₈⁴(16) ring motif. These units are linked via C—H⋯Br hydrogen bonds, forming a three-dimensional network.

Crystal structure of {2-[({2-[(2-amino-eth-yl)amino]-eth-yl}imino)-meth-yl]pheno-lato}aqua-copper(II) bromide

In the mononuclear copper(II) title complex, [Cu(C₁₁H₁₆N₃O)(H₂O)]Br, the Cu^II atom is coordinated by one O and three N atoms of the Schiff base ligand that forms together with one water mol­ecule a slightly distorted [CuN₃O₂] square-pyramidal polyhedron. The deviation of the Cu^II atom from the mean equatorial plane is 0.182 (2) Å. The equatorial plane is nearly coplanar to the aromatic ring of the ligand [angle between planes = 10.4 (1)°], and the water molecule is situated in the apical site. All coordinating atoms (except the imine nitro­gen) and the bromide ion contribute to the formation of the N—H⋯Br, O—H⋯Br and O—H⋯O hydrogen bonds, which link mol­ecules into chains along [01-1].

limit?

This contribution provides an overview on the current legal requirements regarding limits for bromide and presents data on the actual bromide burden of commonly used herbal drugs. Evaluation of an extensive data base shows that results exceeding the limit of 50 mg/kg are found in specific plants which take up bromide to a high extent from the environment. Thus, positive findings of bromide in herbal drugs do not necessarily serve as a proof for methyl bromide treatment. Taking into account the ADI recommended by EMA and WHO, there are no toxicological concerns with regard to the intake of herbal teas, extracts or comminuted herbal drugs at therapeutic doses. Furthermore, the use of methyl bromide and other fumigants must be documented within the batch documentation. If stated in the batch documentation that no fumigation was carried out, it is not necessary to perform the test on bromide. In cases of a particular suspect and if toxicological concerns exist, additional testing can be performed in accordance with the limits set by Regulation (EC) No. 396/2005. For the above reasons, information obtained by performing the test on bromide is not significant for the assessment of quality. Therefore, it seems no longer necessary to maintain bromide in Ph. Eur. general chapter 2.8.13. Pesticide residues and it is recommended to delete it from Table 2.8.13.-1.

Rejection of Bromide and Bromate Ions by a Ceramic Membrane

Effects of pH and the addition of calcium chloride (CaCl(2)) on bromate (BrO(3) (-)) and bromide (Br(-)) rejection by a ceramic membrane were investigated. Rejection of both ions increased with pH. At pH 8, the rejection of BrO(3) (-) and Br(-) was 68% and 63%, respectively. Donnan exclusion appears to play an important role in determining rejection of BrO(3) (-) and Br(-). In the presence of CaCl(2), rejection of BrO(3) (-) and Br(-) ions was greatly reduced, confirming the importance of electrostatic interactions in determining rejection of BrO(3) (-) and Br(-). The effect of Ca(2+) is so pronounced that in most natural waters, rejection of both BrO(3) (-) and Br(-) by the membrane would be extremely small.

Effect of Some Halogenated Hydrocarbons on the Flame Speed of Methane

The effects of five halogenated hydrocarbons on the flame speed of methane have been studied. Bromides are more effective in reducing; flame speeds than are chlorides and the reduction in flame speed is proportional to the amount of inhibitor added.