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Background: Trace elements and potassium bromate represent health risks in food substances owing to their potential toxicity. Methods: Bread samples were obtained from different stores in Ile-Ife, Osun State, Nigeria. The levels of potentially toxic elements (PTEs) (cadmium, chromium, cobalt, copper, lead, manganese, nickel, and zinc) and potassium bromate were determined in the bread samples using Atomic Absorption Spectrophotometer and Ultraviolet Spectrophotometer respectively. Results: The results of the study showed that copper had the highest mean concentration (39.20 ± 1.12 mg/kg) while lead had the lowest mean concentration (0.42 ± 0.02 mg/kg). The levels of the PTEs followed the order: Cu > Zn > Cr > Mn > Ni > Co > Cd > Pb. The concentrations of all the investigated elements exceeded the FAO/WHO legislations. Potassium bromate was undetected in the samples. The target hazard quotients of Cr, Cu, and Cd were greater than 1, as opposed to the other elements which were less than 1. The children were the more vulnerable population given that their total target hazard quotient (35.09) was higher than the adults (9.35) equivalent. Carcinogenic health risks (CR > 10−5) were associated with bread consumption. Conclusion: Due to possible contamination sources emanating from used equipments and processing methods, compliance with regulatory agencies towards ensuring a healthy production environment should be enforced.

Perchlorate, chlorate and bromate are ubiquitously present in the environment. Perchlorate and chlorate could affect thyroid functions, while bromate is carcinogenic and has been listed as a possible human carcinogen in group 2B by the International Agency for Research on Cancer (IARC). This study aimed to determine the occurrence of perchlorate, chlorate and bromate in three types of drinking water (n=226) in Shenzhen, and assess potential human exposure risks. The detection rates of chlorate and perchlorate were both greater than 60%, and they were positively correlated in both bottled water and tap water, indicating similar sources. Bromate and chlorate were negatively correlated in tap water, indicating that the production of them in tap water disinfection might restrict each other. The hazard quotient (HQ) and hazard index (HI) values of perchlorate, chlorate and bromate in drinking water were less than 1 regardless of age groups. However, for bromate some individual excess cancer risk (ICER) values in drinking water exceeded the maximum acceptable level, indicating potential cancer risk to Shenzhen residents.

In persulfate-based advanced oxidation processes (PS-AOPs), sulfate radicals (SO 4 ) have been recognized to play more important roles in inducing bromate (BrO •- ) have been recognized to play more important roles in inducing bromate (BrO 3 - indeed dominated the formation of bromate instead of SO • . Quenching experiments were coupled with electron paramagnetic resonance (EPR) detection and chemical probe identification to elucidate the contributions of each radical species. The comparison of different thermal activated persulfates (PDS and PMS) demonstrated that the significant higher bromate formation in HEAT/PMS ([BrO • indeed dominated the formation of bromate instead of SO 4 •- . Quenching experiments were coupled with electron paramagnetic resonance (EPR) detection and chemical probe identification to elucidate the contributions of each radical species. The comparison of different thermal activated persulfates (PDS and PMS) demonstrated that the significant higher bromate formation in HEAT/PMS ([BrO 3 - ]/[Br - ] 0 radicals in HEAT/PMS. Similarly, the bromate formation in UV/PDS ([BrO 3 - ]/[Br - ] 0  = 0.2), was attributable to the higher concentration of HO • radicals in HEAT/PMS. Similarly, the bromate formation in UV/PDS ([BrO 3 - radicals accounted 66.7% and 33.3% for bromate formation. This controversial result can be reconciled by considering the critical intermediate, hypobromic acid/hypobromate (HOBr/BrO - ] 0  = 1.0), with a high concentration of HO • , further underscored the dominant role of HO • . As a result, we quantified that HO • and SO 4 •- in the formation of bromate rather than SO - ), involved in the transformation of Br - to BrO 3 - . HO • radicals have the chemical preference to induce the formation of HOBr/BrO - intermediates (contributing ∼ 60%) relative to SO 4 •- radicals (contributing ∼ 40%). This study highlighted the dominant role of HO • in the formation of bromate rather than SO 4 •- in PS-AOPs and potentially offered novel insights for reducing disinfection byproduct formation by controlling the radical species in AOPs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The widespread use of disinfectants during the global response to the 2019 coronavirus pandemic has increased the co-occurrence of disinfection byproducts (DBPs) and antibiotic resistance genes (ARGs). Although DBPs pose major threats to public health globally, there is limited knowledge regarding their biological effects on ARGs. This study aimed to investigate the effects of two inorganic DBPs (chlorite and bromate) on the conjugative transfer of RP4 plasmid among Escherichia coli strains at environmentally relevant concentrations. Interestingly, the frequency of conjugative transfer was initially inhibited when the exposure time to chlorite or bromate was less than 24 h. However, this inhibition transformed into promotion when the exposure time was extended to 36 h. Short exposures to chlorite or bromate were shown to impede the electron transport chain, resulting in an ATP shortage and subsequently inhibiting conjugative transfer. Consequently, this stimulates the overproduction of reactive oxygen species (ROS) and activation of the SOS response. Upon prolonged exposure, the resurgent energy supply promoted conjugative transfer. These findings offer novel and valuable insights into the effects of environmentally relevant concentrations of inorganic DBPs on the conjugative transfer of ARGs, thereby providing a theoretical basis for the management of DBPs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The baking industries and disinfection of tap water released a considerable amount of bromate into surface water, which has been reported as a carcinogenic compound to mammals. Rotifers play an important role in freshwater ecosystems and are model organisms to assess environmental contamination. In the present study, the effects of different concentrations (0.001, 0.01, 0.1, 1, 10, 100 and 200 mg/L) of bromate on the life-table and population growth parameters were investigated in the rotifer Brachionus calyciflorus. The results showed that the 24-h LC50 of bromate to B. calyciflorus was 365.29 mg/L (95%Cl: 290.37–480.24). Treatments with 0.01, 10 and 200 mg/L bromate shorten the reproductive period. High levels of bromate (100 and 200 mg/L) significantly decreased net reproductive rate, intrinsic rate of population increase, life span, mictic rate of B. calyciflorus. To investigate the underlying mechanisms, swimming speed and antioxidative biomarkers were compared between bromate treatments and the control. The results showed that glutathione (GSH) and malondialdehyde (MDA) contents, total superoxide dismutase (T-SOD) and peroxidase (POD) activities decreased significantly in response to bromate exposure and the reasons required further investigation. Treatments with 0.001–200 mg/L bromate all significantly reduced swimming linear speed to rotifer larvae and treatments with 100–200 mg/L bromate significantly suppressed the swimming linear speed of adult rotifer. These changes would reduce filtration of algal food and could explain the decreased survival and reproduction. Overall, bromate may not show acute toxicity to rotifers, but still have potential adverse effects on rotifer behavior, which may then influence the community structure in aquatic ecosystems.

Ozonation, a viable option for improving wastewater effluent quality, requires process optimization to ensure the organic micropollutants (OMPs) elimination and disinfection under minimized byproduct formation. This study assessed and compared the efficiencies of ozonation (O 3 ) and ozone with hydrogen peroxide (O 3 /H 2 O 2 ) for 70 OMPs elimination, inactivation of three bacteria and three viruses, and formation of bromate and biodegradable organics during the bench-scale O 3 and O 3 /H 2 O 2 treatment of municipal wastewater effluent. 39 OMPs were fully eliminated, and 22 OMPs were considerably eliminated (54 ± 14%) at an ozone dosage of 0.5 gO 3 /gDOC for their high reactivity to ozone or • OH. The chemical kinetics approach accurately predicted the OMP elimination levels based on the rate constants and exposures of ozone and • OH, where the quantum chemical calculation and group contribution method successfully predicted the ozone and • OH rate constants, respectively. Microbial inactivation levels increased with increasing ozone dosage up to ∼3.1 (bacteria) and ∼2.6 (virus) log 10 reductions at 0.7 gO 3 /gDOC. O 3 /H 2 O 2 minimized bromate formation but significantly decreased bacteria/virus inactivation, whereas its impact on OMP elimination was insignificant. Ozonation produced biodegradable organics that were removed by a post-biodegradation treatment, achieving up to 24% DOM mineralization. These results can be useful for optimizing O 3 and O 3 /H 2 O 2 processes for enhanced wastewater treatment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

N-nitrosodimethylamine (NDMA) is formed during ozonation of model compounds with dimethylhydrazine groups, such as daminozide (DMZ) and 2-furaldehyde 2,2-dimethylhydrazone (2-F-DMH) at pH 7 with yields of 100 % and 87 %, respectively. In this study, ozone/hydrogen peroxide (O 3 /H 2 O 2 ) and ozone/peroxymonosulfate (O 3 /PMS) were investigated to control NDMA formation, and O 3 /PMS (50-65 %) was more effective than O 3 /H 2 O 2 (10-25 %) with a ratio of H 2 O 2 or PMS to O 3 of 8:1. The reaction of PMS or H 2 O 2 to decompose ozone could not compete with the ozonation of model compound because of the high second-order rate constants of the ozonation of DMZ (5 ×10 5 M -1 s -1 ) or 2-F-DMH (1.6 ×10 7 M -1 s -1 ). The R ct value of the sulfate radical (SO 4 •- ) showed a linear relationship with NDMA formation, indicating that SO 4 •- significantly contributed to its control. NDMA formation could be further controlled by injecting small quantities of ozone numerous times to minimize the dissolved ozone concentration. The effects of tannic acid, bromide and bicarbonate on NDMA formation were also investigated during ozonation, O 3 /H 2 /PMS processes. Bromate formation was more pronounced in the O 2 , and O 3 /PMS processes. Bromate formation was more pronounced in the O 3 /PMS process than in the O 3 /H 2 O 2 process. Therefore, in practical applications of O 3 /H 2 /PMS processes, the generation of NDMA and bromate should be detected.2 or O 3 /PMS processes, the generation of NDMA and bromate should be detected., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Ozonation of wastewater can reduce the release of organic micropollutants, but may result in the formation of undesirable by-products, such as bromate from bromide. Bromide is one of the most abundant ions in seawater, the primary precursor of bromate during ozonation, and the end product in microbial bromate reduction. Investigations were carried out to compare the concentration of bromide in wastewater in coastal and non-coastal catchment areas, to monitor bromate formation during ozonation, and to assess the potential for subsequent bromate reduction with denitrifying carriers. Higher bromide concentrations were systematically observed in wastewater from coastal catchment areas (0.2-2 mg Br - /L) than in wastewater from non-coastal areas (0.06-0.2 mg Br - /L), resulting in elevated formation of bromate during ozonation. Subsequent investigations of bromate reduction in contact with denitrifying carriers from two full-scale moving bed biofilm reactors (MBBRs) showed that 80 % of the bromate formed during ozonation could be reduced to bromide in 60 min with first-order rate constants of 0.3-0.8 L/(g biomass ·h). Flow-through experiments with denitrifying carriers also showed that combined reduction of bromate and nitrate could be achieved below a concentration of 2 mg NO x -N/L. These findings indicate that bromide-rich wastewater is more likely to be of concern when using ozonation in coastal than in non-coastal areas, and that bromate and nitrate reduction can be combined in a single biofilm reactor.- -N/L. These findings indicate that bromide-rich wastewater is more likely to be of concern when using ozonation in coastal than in non-coastal areas, and that bromate and nitrate reduction can be combined in a single biofilm reactor., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Ozone has been widely applied during drinking water treatment for organic pollutants removal, however, the ozonation by-products such as bromate, aldehydes, and carboxylic acids could be produced. To investigate the ozonation by-products formation and control efficiency, a continuous pilot-scale system was established including conventional treatment and ozone-biological activated carbon (O 3 -BAC) treatment processes in a waterworks that receives bromide-bearing source water from the Yellow River in northern China. It was found that ozonation could reduce the threshold odour number and the haloacetic acids formation potential effectively. As 1.8-2.6 mg/L of ozone was applied, the bromate concentration would exceed the standard of 10 μg/L. Simultaneously, ozonation led to a large number of formaldehyde, methylglyoxal and other aldehydes. At the ozone dosage of 3.0 mg/L, the total concentration of aldehydes reached the highest of 45.4 μg/L. Ammonia and hydrogen peroxide (H 2 O 2 ) addition could inhibit the formation of bromate effectively. The application of H 2 O 2 induced an increase in aldehydes concentration reaching a maximum concentration of 57.6 μg/L. During the BAC treatment, the removal rate of aldehydes would reach 19%-41%. The addition of H 2 O 2 inhibited the formation of bromate but increased the production of aldehydes, thus it is important to search a balance point for controlling bromate and aldehydes simultaneously. The H 2 O 2 /O 3 (g/g) of 1.0 could be possible to control both bromate and aldehydes concentrations within the standards., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The formation of haloacetonitriles (HANs) during chlorination after sulfite/ultraviolet (UV) treatment of bromate (BrO 3 - ) in the presence of amino acids (AAs) was investigated. During sulfite/UV treatment, the primary species hydrated electrons (e aq - ) and hydrogen atom radicals (H) dominated the reduction of BrO 3 - to bromide (Br - ), whereas the sulfite anion radicals (SO 3 - ) and H degraded AAs to produce the intermediates HN=C(CH 3 )-COOH, CH 3 -CH=NH, and CH 3 -C≡N via α‑hydrogen abstraction and NH 2 -hydrogen abstraction mechanisms. During post-chlorination, Br - was converted to HBrO/BrO-, and the HN=C(CH 3 )-COOH, CH 3 -CH=NH, and CH 3 -C≡N groups featured higher bromine utilization factor (BUF) and chlorine utilization factor (CUF) values than AAs, enhancing the formation of dibromoacetonitrile (DBAN) and dichloroacetonitrile (DCAN). The energetic feasibility of the transformation pathway, that is, HN=C(CH 3 )-COOH, CH 3 -CH=NH, and CH 3 -C ≡ N formation via hydrogen abstraction by SO 3 - and H and their further conversion to HANs, was proved by density functional theory calculations, which showed stepwise negative Gibbs free energy changes (ΔG < 0). The effects of pH and water matrices (e.g., HCO 3 - , Cl - , Fe 3+ , and natural organic matter) were comprehensively evaluated. Although 72% of BrO 3 - was removed by sulfite/UV treatment in the presence of AAs, the cytotoxicity index (CTI) and genotoxicity index (GTI) during post-chlorination increased by 213% and 125%, respectively, due to the formation of 24 CX 3 R-type disinfection by-products (DBPs), especially brominated DBPs. Accordingly, more attention should be given to the formation of brominated DBPs during post-chlorination when using sulfite/UV processes to remove BrO 3 - in the presence of AAs. As a solution, using monochloramine instead of chlorine as a disinfectant after the sulfite/UV process could significantly lower the CTI and GTI values by alleviating the formation of brominated DBPs., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled, “Elevated risk of haloacetonitrile formation during post-chlorination when applying sulfite/UV advanced reduction technology to eliminate bromate”., (Copyright © 2021 Elsevier B.V. All rights reserved.)

This study is the first that monitored the presence and levels of chlorite, chlorate and bromate in tap drinking water of Egypt. Three hundred and eight samples were collected from 22 governorates across Egypt and were analyzed using a standardized ion chromatography method. Forty-seven samples were contaminated by one or more of the inorganic disinfection by-products (DBPs) and only 12 samples exceeded the admissible maximum contamination levels (MCLs). The ratio of samples detected, and exceeding the MCLs were low relative to the global literature. Chlorate was the most prevalent inorganic DBPs (40 samples; concentration <12-4082 μg/L) followed by bromate (12 samples; concentration <3-626 μg/L) then chlorite (5 samples; concentration <12-123 μg/L). Chlorite was always below the MCL and had no human health risk even for the worst-case scenario. Bromate is a real challenge as it poses a significant cancer risk even for the median concentrations. None of the inorganic DBPs was detected in the tap drinking water of Beheira, Cairo, Gharbia, Giza, Kafr El Sheikh, Luxor, Monufia, and Suez governorates. This study manifested the importance of routine monitoring, and implementing counter measures to control the levels of the hazardous inorganic DBPs in tap drinking water., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Bromate, a toxic by-product of bromide-containing drinking water after disinfecting with ozone, has attracted much attention in the past two decades. Traditional methods to activate zero-valent metals for reducing bromate are to eliminate their surface oxide layer by acid washing. In this work, for the first time, zero-valent Al (ZVAl) was surface treated by the following procedures including soaking, soaking and freeze-drying, soaking and heat-treating, and γ-Al 2 O 3 covering Al particle surfaces (GCAP). It was found that all of above surface treated ZVAls have an obvious high efficiency for bromate reduction relative to pristine ZVAl. The bromate reduction rate is GCAP > soaking Al > freeze-drying Al > soaking and heat-treating Al > pristine Al, and using GCAP just 30 min is taken to completely reduce bromate to bromide in neutral solution. Mechanism analyses revealed that Al surface treating or covered by fine γ-Al 2 O 3 phase can promote the hydration and breakage of Al surface passive oxide layer, resulting in a fast contact of inner Al with outside ions, leading to a high reduction rate of bromate in neutral solution. XPS analyses indicated that there are no bromate or bromide ions adsorbed on Al particle surfaces, implying that there is a high direct donating efficiency of electrons from inner Al to bromate ions in solution. Furthermore, GCAP has a good reusability and >90% bromate can be reduced even it was reused up to 4 cycles., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The inhibition of bromate formation is a challenge for the application of ozonation in water treatment due to the carcinogenicity and nephrotoxicity of bromate. In this study, the high-mobility lattice oxygen-rich MnOOH nanorods were synthesized successfully and applied for the bromate inhibition during catalytic ozonation in bromide and organic pollutants-containing wastewater treatment. The catalytic ozonation system using lattice oxygen-rich MnOOH nanorods exhibited an excellent performance in bromate control with an inhibition efficiency of 54.1% compared with the sole ozonation process. Furthermore, with the coexistence of 4-nitrophenol, the catalytic ozonation process using lattice oxygen-rich MnOOH nanorods could inhibit the bromate formation and boost the degradation of 4-nitrophenol simultaneously. Based on the experiments of ozone decomposition, surface manganese inactivation and reactive oxygen species detection, the inhibition of bromate could be attributed to the effective decomposition of ozone with generating more ·O 2 and the reduction of bromate into bromide by lattice oxygen-rich MnOOH. The existed surface Mn(IV) on lattice oxygen-rich MnOOH can accept electrons from lattice oxygen and ·O - to generate surface transient Mn(II)/Mn(III), in which Mn(II)/Mn(III) can promote the reduction of bromate into bromide during catalytic ozonation. This study provides a promising strategy for the development of bromate-controlling technologies in water treatment.2 - to generate surface transient Mn(II)/Mn(III), in which Mn(II)/Mn(III) can promote the reduction of bromate into bromide during catalytic ozonation. This study provides a promising strategy for the development of bromate-controlling technologies in water treatment., (Copyright © 2020. Published by Elsevier B.V.)

Removal of bromate (BrO 3 ) has gained increasing attention in drinking water treatment process. Photocatalysis technology is an effective strategy for bromate removal. During the photocatalytic reduction of bromate process, the photo-generated electrons are reductive species toward bromate reduction and photo-generated holes responsible for water oxidation. In this study, the monoclinic bismuth vanadate (BiVO - ) single crystal was developed as a visible photocatalyst for the effective removal of bromate. The as-synthesized BiVO 4 ) single crystal was developed as a visible photocatalyst for the effective removal of bromate. The as-synthesized BiVO 4 photocatalyst with optimized {010} and {110} facets ratio could achieve almost 100% removal efficiency of BrO 3 - driven by visible light with a first-order kinetic constant of 0.0368 min -1 . As demonstrated by the electron scavenger experiment and density functional theory (DFT) calculations, the exposed facets of BiVO 4 should account for the high photocatalytic reduction efficiency. Under visible light illumination, the photo-generated electron and holes were spatially transferred to {010} facets and {110} facets, respectively. The BiVO 4 single crystal photocatalyst may serve as an attractive photocatalyst by virtue of its response to the visible light, spatially charge transfer and separation as well as high photocatalytic activity, which will make the removal of BrO 3 - in water much easier, more economical and more sustainable., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled “Tuning Electron Transfer by Crystal Facet Engineering of BiVO(4) for Boosting Visible-Light Driven Photocatalytic Reduction of Bromate”., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The baking industries and disinfection of tap water released a considerable amount of bromate into surface water, which has been reported as a carcinogenic compound to mammals. Rotifers play an important role in freshwater ecosystems and are model organisms to assess environmental contamination. In the present study, the effects of different concentrations (0.001, 0.01, 0.1, 1, 10, 100 and 200 mg/L) of bromate on the life-table and population growth parameters were investigated in the rotifer Brachionus calyciflorus. The results showed that the 24-h LC 50 of bromate to B. calyciflorus was 365.29 mg/L (95%Cl: 290.37-480.24). Treatments with 0.01, 10 and 200 mg/L bromate shorten the reproductive period. High levels of bromate (100 and 200 mg/L) significantly decreased net reproductive rate, intrinsic rate of population increase, life span, mictic rate of B. calyciflorus. To investigate the underlying mechanisms, swimming speed and antioxidative biomarkers were compared between bromate treatments and the control. The results showed that glutathione (GSH) and malondialdehyde (MDA) contents, total superoxide dismutase (T-SOD) and peroxidase (POD) activities decreased significantly in response to bromate exposure and the reasons required further investigation. Treatments with 0.001-200 mg/L bromate all significantly reduced swimming linear speed to rotifer larvae and treatments with 100-200 mg/L bromate significantly suppressed the swimming linear speed of adult rotifer. These changes would reduce filtration of algal food and could explain the decreased survival and reproduction. Overall, bromate may not show acute toxicity to rotifers, but still have potential adverse effects on rotifer behavior, which may then influence the community structure in aquatic ecosystems., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Ozone-based technologies are used for micro-pollutants removal in wastewater treatment. However, the generation of the toxic by-product bromate (BrO 3 - ) is of a great concern. LaCoO 3 (LCO) catalytic ozonation has been used to overcome this significant drawback in the sole ozonation, achieving better BrO 3 - elimination efficiency. However, a key challenge is how to enhance micro-pollutant (benzotriazole, BZA) degradation efficiency and to eliminate formed BrO 3 - synchronously under various water qualities in drinking water or wastewater treatment. Therefore, the objective of this study is to propose a practical strategy of BZA removal and BrO 3 - reduction synchronously in water or wastewater treatment. In this study, important factors influencing BZA removal and BrO 3 - reduction were investigated, including [catalyst], [BZA], initial pH solution, [NH 4 + -N] and [(bi)carbonate alkalinity]. Based on the performance and mechanism of these effects, a practical strategy for BZA degradation and BrO 3 - elimination with and without Br - in the influent was developed. Additionally, the density functional theory (DFT) calculation successfully predicted the attack site on BZA by molecular ozone and formed hydroxyl radical (HO·) during LCO catalytic ozonation. Fukui indexes of f + and f 0 were calculated to forecast direct ozone molecule and HO· attack, respectively. Combination of DFT calculation with intermediates that identified through liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS), BZA degradation pathway was established more accurately. Additionally, four new intermediates were identified in this study. Overall, this study proposes a useful strategy for synchronous micro-pollutants degradation and BrO 3 - elimination, while also suggesting the feasibility of LCO catalytic ozonation for water or wastewater purification., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The UV/Chlorine process has gained attention in recent years due to the high quantum yield and absorbance of the chlorine species. However, there are still many unknowns around its application as a treatment for drinking water. The potential for the formation of disinfection by-products (DBPs) is one of them. There are no studies reporting on the formation of trihalomethanes (THMs) or haloacetic acids (HAAs) in complex matrices, such as real source waters, at UV wavelengths tailored to the UV/Chlorine process, which has been possible thanks to the development of light emitting diodes (LEDs). In addition, consideration of mitigation measures that might be needed after UV/Chlorine treatment for full scale application have not been previously reported. Specifically, the novelty of this work resides in the use of an innovative reactor using UV-LEDs emitting at 285 nm for the removal of three pesticides (metaldehyde, carbetamide and mecoprop), the evaluation of THM, HAA and bromate formation in real water sources by UV/Chlorine treatment and the mitigation effect of subsequent GAC treatment. A new parameter, the applied optical dose (AOD), has been defined for UV reactors, such as the one in the present study, where the irradiated volume is non-uniform. The results showed the feasibility of using the UV/Chlorine process with LEDs, although a compromise is needed between pH and chlorine concentration to remove pesticides while minimising DBP formation. Overall, the UV/Chlorine process did not significantly increase THM or HAA formation at pH 7.9-8.2 at the studied wavelength. At acidic pH, however, THM formation potential increased up to 30% after UV/Chlorine treatment with concentrations up to 60 μg/L. HAA formation potential increased between 100 and 180%, although concentrations never exceeded 35 μg/L. In all cases, GAC treatment mitigated DBP formation, reducing THM formation potential to concentrations between 3 and 16 μg/L, and HAA formation potential between 4 and 30 μg/L., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Potassium bromate is a food additive used as "flour improver" in the baking industry. Bromate is considered a carcinogenic and nephrotoxic substance. Thus, the bromate concentration must be carefully monitored in flour products. We developed a method for a selective and sensitive determination of bromate in flour that uses ion chromatography coupled with single quadrupole mass spectrometry (IC -MS). A recently introduced high-capacity anion-exchange column was used to separate bromate from matrix anions. Six commercial flour and flour products including homemade bread baked using flour containing potassium bromate, were analyzed. The method showed good precision with RSDs <0.2%, and <5% (n = 8), for retention time and peak area respectively. Bromate recoveries from flour samples ranged from 86 to 110%. The limits of detection and quantitation of bromate in the prepared solution were 0.10 µg/L and 0.34 µg/L, respectively, which corresponded to 5 µg/kg and 17 µg/kg in bread., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019. Published by Elsevier B.V.)

Drinking water is an important source of human exposure to bromate, an ubiquitous environmental contaminant and a suspect human carcinogen. Nevertheless, little is known with regard to bromate exposure from water produced by thermal desalination of seawater. The purpose of this study was to determine the occurrence of bromate in desalinated drinking water and groundwater from Kuwait and estimate associated exposure and health risks to consumers. In this study, 194 tap and ground water samples collected from Kuwait were analyzed for the presence of bromate and bromide (reduced form of bromine). Bromate was found in almost all tap water samples with a mean concentration of 19.6 μg/L, which is higher than the maximum acceptable contaminant level (MCL) of 10 μg/L. The mean concentration of bromide in tap water samples was 46.2 μg/L. In bottled water, lower mean bromate concentration was found (2.89 μg/L) with mean bromide levels at 76.1 μg/L. Saline brackish water had bromate concentration at 9.48 μg/L while bromate was not detected in saline groundwater/well water samples. The mean estimated daily intake (EDI) of bromate by the Kuwaiti population through tap water and commonly consumed bottled water was 21.7 μg/d and 3.21 μg/d, respectively. Among the five age groups, 3 to 5-year-old children had the highest EDI of bromate at 15.4 μg/d. The excess cancer risk due to ingestion of bromate in tap water was estimated to be 3.92 × 10 -4 , which is approximately one order of magnitude higher than the maximum acceptable level of risk (2× 10 -5 ). This study highlights the significance of desalinated water as a source of bromate exposure., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Bromide-enhanced ozonation (BEO) process can be a fast and effective solution for the complete removal of total nitrogen (TN) from wastewaters containing from moderate to high concentrations of ammonia nitrogen (AN). Like the traditional biological process of AN oxidation, even BEO requires the presence of buffering agents, in order to oppose the progressive acidification induced by the reaction. This study compares the effect of two buffering substances (namely bicarbonate and mixtures of orthophosphates) in hindering the acidification caused by AN oxidation and, consequently, optimizing the overall efficiency of the process. Tests were carried out with on-purpose made solutions containing concentrations of AN of 5-10 mM. The range of [Br - ]/[O 3 ] ratio values was from 12 to 18, so as to make ozone the limiting factor in HOBr generation. The results of this study proved that, in the absence of natural buffering agents, mixtures of orthophosphates must be preferred to the more traditionally employed bicarbonate to control the pH evolution of BEO process. In fact, orthophosphates proved to be capable to guarantee an initial pH of the wastewater in the order of 7.5, thus making the zero-order AN removal rates 15% faster than those observed in the presence of bicarbonate. Furthermore, in the presence of mixtures of orthophosphates, the generation of ozonation byproducts in the oxidized form (nitrate, bromate) was reduced by over 70%. Finally, the fine control of pH obtained with orthophosphates in the BEO of AN makes that process an attractive solution for the treatment of effluents containing AN, thus preventing the discharge of residual nitrogen into aquatic environments and avoiding eutrophication of receiving water bodies., (Copyright © 2019 Elsevier B.V. All rights reserved.)

This work focuses on the intensification of BrO 3 - (200 μg L -1 ) reduction by TiO 2 -assisted heterogeneous photocatalysis, using the NETmix mili-photoreactor illuminated by UVA light-emitting diodes (UVA-LEDs). The mili-photoreactor was assembled in two configurations: i) catalyst deposition on the channels and chambers of a back stainless steel slab (SSS) and ii) catalyst deposition on the front borosilicate glass slab (BGS), allowing the study of front-side (FSI) and back-side (BSI) illumination mechanisms, respectively. The BrO 3 - reduction rate in aqueous solution was assessed as a function of: i) pH; ii) dissolved oxygen (DO); iii) addition of formic acid (CH 2 O 2 ) as a sacrificial agent (SA); iv) photocatalyst film thickness; v) illumination mechanism; vi) irradiation intensity; vii) temperature; and viii) water matrix. Higher BrO 3 - reduction rates were observed using the FSI mechanism and lower pH values. Nitrogen injection (to eliminate DO) did not significantly improve the reaction rate and the addition of CH 2 O 2 had a negative effect at pH 6.5. Neither temperature nor irradiance increase showed a considerable improvement on the reduction rate. Moreover, TiO 2 film remains stable for at least 13 consecutive reactions without significant catalyst leaching. The chemically pre-treated fresh water (FW) matrix negatively affected the reaction rate when compared with the synthetic water (SW), under the best operational conditions (SSS: pH = 5.5, 287 mg of TiO 2 , 25 °C, SA absence, [DO] = 232-263 μM). This was associated with the presence of both inorganic and organic matter at much higher concentrations than BrO 3 - . Notwithstanding, heterogeneous TiO 2 photocatalysis, using the NETmix mili-photoreactor, was successfully applied to fresh water, achieving [BrO 3 - ] < 10 μg L -1 (guideline value) after 2-hour reaction., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Bicarbonate scavenges OH to form CO 3 that enhances the bromate formation by ozonation. However, the role of CO - in the bromate formation during ozonation has never been quantitatively investigated. Herein, we establish a quantitative approach for evaluating the role played by CO 3 - -involved bromate and CO 3 - -involved bromate was responsible for 33.7-69.9% of the total bromate formed with bicarbonate concentrations from 0.5 mM to 4 mM. The CO 3 - plays a comparable or even more pronounced role in the oxidation of bromine during bromate formation than OH. A model was developed based on the ratio of bromine oxidized by CO 3 - -involved bromate formation well. Modeled and experimental results illustrated that the contribution of the CO 3 -involved bromate to the total bromate decreased with increasing pH or initial bromide, but almost remained unchanged at different ozone dosages. Moreover, the presence of humic acid led to an increase in this contribution during ozonation. The results of this study provide a more in-depth understanding of the mechanism of bromate formation during ozonation.- -involved bromate was responsible for 33.7-69.9% of the total bromate formed with bicarbonate concentrations from 0.5 mM to 4 mM. The CO 3 - exposure was two orders of magnitude higher than the corresponding OH exposure during ozonation. These results demonstrate that CO 3 - plays a comparable or even more pronounced role in the oxidation of bromine during bromate formation than OH. A model was developed based on the ratio of bromine oxidized by CO 3 - , which could predict the CO 3 - -involved bromate formation well. Modeled and experimental results illustrated that the contribution of the CO 3 - -involved bromate to the total bromate decreased with increasing pH or initial bromide, but almost remained unchanged at different ozone dosages. Moreover, the presence of humic acid led to an increase in this contribution during ozonation. The results of this study provide a more in-depth understanding of the mechanism of bromate formation during ozonation., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The study investigates the degradation of 2,4,6-tribromophenol (2,4,6-TBP) and the influence of solution pH, alkalinity, H 2 O 2 and O 3 dosage. Debromination efficiency of 2,4,6-TBP was the highest in basic water (pH = 10.61). The extent of TOC removal compared favourably with the amount of substrate converted, suggesting favourable mineralization of oxygenated by-products (OBPs). Ozonation in basic water favoured the formation of toxicBrO 3 - , while in acidic water (pH = 2.27) BrO 3 - yield was lowest. In acidic water the presence of CO 3 2- showed negligible effect on conversion, TOC and  BrO 3 - yield compared to ozonation alone. In basic water both 2,4,6-TBP conversion and TOC removal decreased with an increase in CO 3 2- , hence minimizing BrO 3 - formation. The O 3 /H 2 O 2 process showed an improvement in the debromination efficiency and TOC data revealed that total mineralization of OBP's was achieved. However, only 10% H 2 O 2 was able to effectively decrease BrO 3 - formation. Increasing the ozone concentration from 20 to 100 ppm enhanced the conversion of 2,4,6-TBP and TOC removal. At low ozone concentrations poor mineralization of OBP's occurred, while complete mineralization was achieved at higher ozone dose. The reaction pathways for ozone degradation of 2,4,6-TBP in acidic and basic waters is proposed., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A flexible catalyst, Fe-Cu-MCM-41, was employed to enhance diclofenac (DCF) mineralization and inhibit bromate formation in catalytic ozonation process. Greater TOC removal was achieved in Fe-Cu-MCM-41/O 3 process (78%) than those in Fe-MCM-41/O 3 (65%), Cu-MCM-41/O 3 (73%) and sole ozonation (42%). But it was interesting that both Cu-MCM-41/O 3 and Fe-MCM-41/O 3 achieved 93% bromate inhibition efficiency, only 71% inhibition efficiency was observed in Fe-Cu-MCM-41/O 3 . Influence of pH, TBA/NaHSO 3 and detection of by-products were conducted to explore the mechanism. By Pyridine adsorption-IR and XPS, a relationship was found among activity of catalysts, Lewis acid sites and electron transfer effect between Fe (II/III) and Cu (I/II). Fe-Cu-MCM-41 promoted ozone decomposition to generate OH, which accounted for enhanced DCF mineralization. The consumption of aqueous O 3 also suppressed the oxidative of Br - and HBrO/Br - . More HBrO/BrO - accumulated in catalytic ozonation process and less bromate generated. Bromate formation in Fe-Cu-MCM-41/O 3 process was sensitive with pH value, the acidic condition was not favor for bromate formation. Both DCF mineralization and bromate inhibition were influenced by surface reaction. Moreover, Fe-Cu-MCM-41 showed excellent catalytic performance in suppressing the accumulation of carboxylic acid, especially for oxalic acid. Nearly no oxalic acid was detected during Fe-Cu-MCM-41/O 3 process., (Copyright © 2017 Elsevier B.V. All rights reserved.)

In this study, the microbial community for bromate reduction in a rotating biofilm-electrode reactor (RBER) was investigated. Continuous experiment demonstrated that the bromate reduction by an auto-hydrogenotrophic microbial community was inhibited by high concentration nitrate (50mg/L). The bacterial diversity of RBER were examined through the analyse of 16S rRNA gene sequences of clone libraries. The results showed that the bromate-reducing bacteria were phylogenetically diverse at the phylum level, representing the Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria. The relative abundances of these microbial community represented 99.1% of all phylum in the biofilms when bromate served as the sole electron acceptor. Meanwhile, the Bacillus strains became the largest phylotype and represented about 37% of the total bacteria in the biofilm, indicating that the genus Bacillus played the key role in the auto-hydrogenotrophic process. Moreover, three new bacterial genera, Exiguobacterium, Arthrobacter and Chlorobium appeared with the respective relative abundance being about 7.37%, 1.81%, and 0.52%, which might be the bromate-specific reducing bacteria., (Copyright © 2017 Elsevier B.V. All rights reserved.)

A selective, sensitive and useful method, based on modified QuEChERS cleanup combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the negative-ion electrospray ionization (ESI - ) mode, was developed and validated for the simultaneous determination of three inorganic anions including perchlorate (ClO 4 ), bromate (BrO - ), bromate (BrO 3 - ) and hypophosphite (H 2 >0.999) for all analytes in their respective concentration ranges. The ILOQs and MLOQs for perchlorate, bromate and hypophosphite were 0.1, 0.5, 5.0μg/L and 2.0, 6.0, 60.0μg/L, respectively. The average recoveries of three target analytes from the negative samples spiked at three different concentrations were in a range from 84.6% to 104.9%. The intra-day precision (n=6) and inter-day precision (n=5) of the target analytes were in the ranges of 2.9%-6.9% and 6.4%-8.2%. The matrix effect of this method was observed between 0.83 and 1.17 and was acceptable. The validated method was successfully applied to determine the concentrations of these inorganic anions in flour. Results found that perchlorate and hypophosphite were detected in 33 out of 50 and 7 out of 50 flour samples.2 - ) in flour. The extraction parameters and LC-MS/MS conditions were optimized by single-factor experiment and sorbent combination in modified QuEChERS clean-up was optimized through response surface analysis. Three target analytes were separated on a normal-phase Phenomenex Luna Silica (2) column (150mm×2.0mm, 5μm, 100Å) with the mobile phase of a mixture of 5mmol/L ammonium acetate water solution and acetonitrile, detected by MS/MS under multiple reaction monitoring and quantified by external standard method. The developed method was validated in terms of the sensitivity, linearity, accuracy and precision, and matrix effect. The method showed a good linearity (R 2 >0.999) for all analytes in their respective concentration ranges. The ILOQs and MLOQs for perchlorate, bromate and hypophosphite were 0.1, 0.5, 5.0μg/L and 2.0, 6.0, 60.0μg/L, respectively. The average recoveries of three target analytes from the negative samples spiked at three different concentrations were in a range from 84.6% to 104.9%. The intra-day precision (n=6) and inter-day precision (n=5) of the target analytes were in the ranges of 2.9%-6.9% and 6.4%-8.2%. The matrix effect of this method was observed between 0.83 and 1.17 and was acceptable. The validated method was successfully applied to determine the concentrations of these inorganic anions in flour. Results found that perchlorate and hypophosphite were detected in 33 out of 50 and 7 out of 50 flour samples., (Copyright © 2017 Elsevier B.V. All rights reserved.)

An ordered mesoporous Mg-Al layered double hydroxide (meso-LDH350) with a fairly high Brunauer-Emmett-Teller (BET) surface area (126m 2 g -1 ) has been facilely synthesized and then evaluated for the adsorptive removal of bromate from aqueous solutions. Adsorbents were characterized by a variety of techniques (e.g., XRD, FTIR, SEM, TG-DSC, N 2 physisorption, XPS, etc.). The adsorption studies indicated that the presence of background electrolytes and competitive anions can obviously repress the uptake of bromate on LDHs. The adsorption isotherms agree well with the Langmuir model, giving a maximum adsorption capacity of 59.34mgg -1 (pH 7.5, 10°C) for meso-LDH350, which is much higher than other LDH-type adsorbents reported in literature. The adsorption kinetic data can be well fitted with the pseudo-second-order rate model. Based on the macroscopic and microscopic studies, bromate adsorption on meso-LDH350 was associated with two mechanisms: the reconstruction of the layered structures of meso-LDH350 and the anion-exchange between bromate and the intercalated anions., (Copyright © 2017. Published by Elsevier B.V.)

The addition of oxidants for disinfecting water can lead to the formation of potentially carcinogenic compounds referred to as disinfection byproducts (DBPs). Haloacetic acids (HAAs) are one of the most widely detected DBPs in US water utilities and some of them are regulated by the US Environmental Protection Agency (USEPA). The present study developed a method to analyze all the compounds in the USEPA method 557 (nine HAAs, bromate and dalapon) plus four potentially more toxic iodinated HAAs in water by coupling ion chromatography with tandem mass spectrometry (IC-MS/MS). This aqueous direct injection method has significant advantages over traditional GC methods, which require a derivatization and sample extraction that are laborious, time-consuming, and can negatively impact reproducibility. The method developed in this study requires half the time of the current USEPA method 557 on IC-MS/MS while including more compounds and achieving sub-μg/L level method detection limits (MDLs) for all 15 target analytes. The single laboratory lowest concentration minimum reporting level (LCMRL) has also been determined in reagent water, which ranged from 0.011 to 0.62μg/L for the analytes. The mean recoveries of the analytes during matrix spike recovery tests were 77-125% in finished drinking water and 81-112% in surface water. This method was then applied to untreated, chlorinated, and chloraminated groundwater and surface water samples. Bromate and 9 HAAs were detected at different levels in some of these samples., (Copyright © 2017 Elsevier B.V. All rights reserved.)