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The multi-pathway cancer risk (CR) assessment of trihalomethanes (THM) involves considering exposure via ingestion, dermal contact, and inhalation. Inhalation occurs during showering due to the volatilization of THMs from chlorinated water to the air. When assessing inhalation risks, exposure models commonly assume that the initial THM concentration in the shower room is zero. However, this assumption is only valid in private shower rooms where single or infrequent showering events take place. It fails to account for continuous or successive showering events in shared showering facilities. To address this issue, we incorporated the accumulation of THM in the shower room air. We studied a community (population ≈ 20,000) comprising two types of residences with the same water supply: population A with private shower rooms, and population B with communal shower stalls. The total THM concentration in the water was 30.22 ± 14.45 µg L−1. For population A, the total CR was 58.5 × 10−6, including an inhalation risk of 1.11 × 10−6. However, for population B, the accumulation of THM in the shower stall air resulted in increased inhalation risk. By the tenth showering event, the inhalation risk was 2.2 × 10−6, and the equivalent total CR was 59.64 × 10−6. We found that the CR significantly increased with increasing shower duration. Nevertheless, introducing a ventilation rate of 5 L s−1 in the shower stall reduced the inhalation CR from 1.2 × 10−6 to 7.9 × 10−7. [ABSTRACT FROM AUTHOR]

With the reform of China's urbanization increasing in popularity, the security issues posed by urban groundwater, especially groundwater in industrial areas, have attracted scholars' attention. This research aimed to predict and quantify the migration process of contaminants in a microconfined aquifer by conducting a groundwater contamination investigation in an abandoned chemical plant in the Jiangsu Province of China. First, data such as regional hydrogeological parameters and types of contaminants were obtained via hydrogeological drilling, groundwater well monitoring, pumping tests, and laboratory permeability tests, which helped identify the most serious pollution factor: chloroform. Then, a groundwater flow model was built using the Groundwater Modeling System (GMS) and verified using the general-purpose parameter estimation (PEST) package. In addition, based on the three-dimensional multi-species model for transport (MT3DMS) in GMS, a transport model was established. The results illustrate that the plume range of chloroform diffuses with water flow, but, because of its slow diffusion rate and inability to degrade naturally, the concentration of the contaminant has remained several times higher than the safety standard for a long time. The contaminant spread vertically to the soil layer above the microconfined aquifer under pressure, resulting in direct pollution. In addition, the contaminant in the microconfined aquifer is anticipated to migrate down to the clay layer and become enriched. However, the first confined aquifer has not been seriously polluted in the past 20 years. Finally, a sensitivity analysis of the parameters shows that groundwater contamination in the Yangtze delta region is greatly affected by precipitation recharge and hydraulic conductivity. [ABSTRACT FROM AUTHOR]

Copyright of Asian Journals of Ecotoxicology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Swimming is a physical activity that is accessible to people of all ages in all seasons. However, continuous organic and inorganic precursor load and disinfectant dosing make pool water chemistry much more complex than other disinfected waters. Carcinogenic bromate compound is one of the hundreds of disinfection by-products in pool water. The occurrence of bromate in pool waters depends on the precursor content of filling water, the disinfection process, operating parameters, and the purity of disinfectants. While the average filling water bromide concentrations of University Campus indoor swimming pool in Gülbahçe -Urla (SP1) and Buca public indoor swimming pool (SP2) were determined to be 182 µg/L and 11.0 µg/L, respectively, the average bromate concentrations of SP1 and SP2 were 59.4 µg/L and 68.3 µg/L. Estimated chronic-toxic health risks of accidental ingestion of pool water during swimming (between 10-3 and 10-1) were lower than the threshold level ('1'). Although the carcinogenic risks in central tendency scenario (<10-6) indicate negligible risks for swimmers, worst case scenario indicates carcinogenic risks (medians were ranged from 1.61×10-6 to 9.42×10-6) for highly exposed specific swimmer groups. Bromate accumulation in swimming pools needs attention for mitigating the health risks for swimmers. [ABSTRACT FROM AUTHOR]

While it is known that exposure to disinfection by-products (DBPs), including trihalomethanes (THMs), impairs liver function, few epidemiological studies have explored this association. Here, we determined the concentrations of four urinary trihalomethanes (chloroform [TCM], and three Br-THMs, bromodichloromethane [BDCM], dibromochloromethane [DBCM], and bromoform [TBM]), and nine serum liver function indicators in 182 adults ≥ 18 years of age, examined at a medical examination center in Wuxi, China, in 2020 and 2021. Generalized linear model analysis revealed positive associations between urinary DBCM and alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), total protein (TP), and albumin (ALB). Urinary Br-THMs and total THMs (TTHMs) were positively associated with ALT, AST, TBIL, indirect bilirubin (IBIL), TP, and ALB (all P < 0.05). Urinary THMs were not associated with alkaline phosphatase (ALP) or glutamine transaminase (GGT) (all P > 0.05). Generalized additive model–based penalized regression splines were used to confirm these associations. In conclusion, THM exposure was associated with altered serum biomarkers of liver function. [ABSTRACT FROM AUTHOR]

Dichloroacetic acid (DCAA), one of the disinfection by‐products in water, has showed critical harm to human health since it can cause cancer, teratogen and mutagen. Herein, a quaternized hollow fiber membrane was fabricated by ring‐open reaction via a facile one‐step immersion method, which could fast adsorb DCAA by flow‐through adsorption. The obtained membrane with a sponge pore structure, which was quaternized at 60°C in an alkaline solution, exhibited excellent adsorption performance with removal percentage of 100%, life span up to 100 L and treating capacity of 24.8 mg m−2. Meanwhile, the optimal membrane exhibited the exceptional performance in a neutral test solution compared with acid or alkaline test solution. It was concluded that electrostatic attraction between positively charged quaternary ammonium groups and negatively charged DCAA was responsible for the adsorption mechanism. Additionally, fitting results indicated that the adsorption of DCAA onto the membrane was mainly dominated by homogeneous monolayer adsorption. This work developed a facile approach to prepare a novel quaternized membrane with outstanding adsorption performance, which demonstrated huge potentials in the molecular separation and water purification fields. [ABSTRACT FROM AUTHOR]

In the process of sewage treatment, the characteristics of dissolved organic matter (DOM) are always changed during chemical and biological processes, affecting the generation of disinfection by-products (DBPs) compositions at the following disinfection stage. The present study systematically investigated the effect of DOM characterization on C- and N-DBPs formation at AAO-MBR reactor when treating wastewater. The results showed that the AAO-MBR treatment process could efficiently eliminate dissolved organic carbon (DOC) and ammonium nitrogen (NH4+-N) from wastewater with an elimination rate of 89% and 98%, respectively. Most of the precursors (i.e., 56.8% C-DBPs and 78.1% N-DBPs) were removed at the MBR unit, while AGC and AAO units promoted the formation of DBPs precursors. More specifically, soluble microbial products (SMPs) and humus acid were increased, which led to improved C- and N-DBPs via aerated grit chamber (AGC) treatment. At the AAO treatment unit, the content of low MW hydrophobic SMPs, humus acid, and polysaccharides was increased, indicating low MW and HPO fractions dominating the C- and N-DBPs. MBR treatment improved C-DBPs in high MW and HPO fractions and N-DBPs in low MW and HPO fractions, which is explained by higher MW hydrophobic SMPs and humus acids, compared to the AAO unit. The present study provided deep insight into the linkage of DOM characteristics and C- and N-DBPs formation at each treatment unit during the AAO-MBR process. [ABSTRACT FROM AUTHOR]

Like all public utility, swimming pools had been treated with special procedures during the COVID- 19 pandemic. In addition to the basic rules (social distance + hand disinfection + masks), applicable to all citizens, the managers of swimming pools were obliged to reduce the number of swimmers and to increase the effects of water treatment. Monitoring, control and rapid response to unfavourable changes in the quality of swimming pool water are the basis for minimizing the risk of disease transmission or exposure of bathers to pathogens. The main purpose of this work is to analyse and compare the quality of swimming pool water in a municipal outdoor swimming pool complex, before (2018–2019) and during the COVID-19 pandemic (2020–2021). Water samples taken from a paddling pool for children (CP), a recreational pool (RP), and a sports pool (SP) were analysed. The results of the research, based on real case studies, were compared with the documents on water quality in swimming pools in force at the time. An analysis was carried out to determine the relationships between swimming pool water quality before and during the COVID-19 pandemic. The tested parameters determining the quality of water were physico-chemical parameters (temperature, pH, redox, turbidity, nitrates, chemical oxygen demand, free chlorine, chloramines and trihalomethane THM) and bacteriological parameters (colony forming units CFU of Pseudomonas aeruginosa, Escherichia coli, Legionella sp.). Based on the results of the analysis of the parameters mentioned-above, the validation of the procedures applied during the COVID-19 hazard and their impact on the quality of swimming pool water were evaluated. The results of the pool water quality tests were discussed with particular emphasis on disinfection by-products (THM and combined chlorine). Detailed analysis showed better water quality in the first year of the pandemic (2020) compared to 2018–2019 (before COVID-19) and 2021 (the second year of COVID-19 pandemic). The following parameters were found to be significantly different: THM (before 0.069 mg/L and during 0.034 mg/L), free chlorine (before 0.86 mg/L and during 0.66 mg/L), and redox potential (before 667 and during 713 mV). [ABSTRACT FROM AUTHOR]

The hydrophilic substances in natural organic matter (NOM) are the main precursor of disinfection by-products (DBPs) formed during disinfection processes. The fractionation of the components in NOM based on hydrophilicity contributes to elaborating the behavior of NOM during disinfection. However, the traditional NOM fractionation method using two hydrophobic resins of DAX-8 and XAD-4 lays emphasis on the separation of hydrophobic substances, limiting the thorough study of the hydrophilic components in NOM. In this work, the amphiphilic resin NDAM was employed as a replacement of XAD-4 to realize more thorough separation of the hydrophilic substances. Compared with the divinylbenzene (DVB) structure of XAD-4, the NDAM possesses a more hydrophilic skeleton of N-vinylpyrrolidone (NVP) and DVB which favors the adsorption of hydrophilic components in NOM. The two fractionation methods of DAX-8 + XAD-4 and DAX-8 + NDAM were applied to fractionate NOM, and the obtained fractions were characterized via fluorescence spectra, UV spectra, acid–base titration, the partition coefficients of aqueous two-phase systems(ATPs), and 1H nuclear magnetic resonance (1H-NMR). The results showed that the transphilic fractions separated by XAD-4 accounted for 11.09% of NOM, while the proportion increased to 20.33% with the method of NDAM fractionation. Besides, the hydrophilic components enriched by NDAM not only have more π-conjugated systems and more aromatic structure but also contain more oxygen-containing and nitrogen-containing functional groups. In addition, the hydrophilic fractions separated by NDAM contained more DBP precursors. The NDAM separates more NOM which can produce bromine-containing DBPs into HPIA, and the DBP productivity of HPIN is significantly higher than that of XAD-4. In general, the NOM fractionation method proposed in this study utilizing NDAM resin could fractionate the hydrophilic fractions in NOM more thoroughly, showing application potential in the analysis and control of DBPs formed from NOM. [ABSTRACT FROM AUTHOR]

• HO• and RNS during VUV photolysis of NO3− contributed to TCNM formation. • Solution pH, chloride and bicarbonate cannot effectively dimmish TCNM formation. • TCNM formation showed a linear relationship with the Hammett constant. • Newly formed 1161 nitrogen-containing compounds have higher aromaticity. • Results indicated TCNM formation risk of VUV applying in water treatment. Vacuum ultraviolet (VUV) photolysis is recognized as an environmental-friendly treatment process. Nitrate (NO 3 −) and natural organic matter (NOM) are widely present in water source. We investigated trichloronitromethane (TCNM) formation during chlorination after VUV photolysis, because TCNM is an unregulated highly toxic disinfection byproduct. In this study: (1) we found reactive nitrogen species that is generated under VUV photolysis of NO 3 − react with organic matter to form nitrogen-containing compounds and subsequently form TCNM during chlorination; (2) we found the mere presence of 0.1 mmol/L NO 3 − can result in the formation of up to 63.96 µg/L TCNM; (3) we found the changes in pH (6.0-8.0), chloride (1-4 mmol/L), and bicarbonate (1-4 mmol/L) cannot effectively diminish TCNM formation; and, (4) we established the quantitative structure-activity relationship (QSAR) model, which indicated a linear relationship between TCNM formation and the Hammett constant (σ) of model compounds; and, (5) we characterized TCNM precursors in water matrix after VUV photolysis and found 1161 much more nitrogen-containing compounds with higher aromaticity were generated. Overall, this study indicates more attention should be paid to reducing the formation risk of TCNM when applying VUV photolysis process at scale. [Display omitted]. [ABSTRACT FROM AUTHOR]

Watersheds with relatively higher concentrations of disinfection by-product (DBP) precursors are of concern for public water systems (PWSs) seeking to control DBP exposure risk. In this study, the occurrence of bromide and total organic carbon (TOC), which are important DBP precursors, was evaluated in PWS source waters on a watershed basis at the hydrologic unit code 2 (HUC2) level. Variations were examined across source water type (e.g., surface water or groundwater) and watershed, and temporally based on seasonality as well as differences between the late 1990s and the years 2018–2020. The median bromide concentrations were higher in groundwater systems compared with surface water (by 25 μg/L), whereas the median TOC concentrations were higher in surface water systems compared with groundwater (by 1.7 mg/L). Surface water sources in multiple midwestern and western watersheds had a combination of elevated bromide and TOC (relative to median values of 21 μg/L and 2.5 mg/L, respectively), which was especially pronounced in the Texas-Gulf and Rio Grande watersheds. None of the HUC2 watersheds had elevated levels of both bromide and TOC in groundwater sources (median values of 50 μg/L and 1.0 mg/L, respectively). Source water bromide median watershed concentrations for very large systems were ∼20% lower in 2018–2020 than in 1998, however, more than 40% higher at the 90th percentile, whereas source water TOC median watershed concentrations for very large systems were ∼25% higher in 2018–2020 than in 1998 but less than 10% higher at the 90th percentile. These temporal differences may be related to the influence of climate change and other anthropogenic effects. In addition, many individual PWSs showed substantial change in bromide and TOC concentrations between those time periods. For example, about 7% of the PWSs had at least double the bromide concentrations, and 5% at least double the TOC concentrations, in 2018–2020 than in 1998. [ABSTRACT FROM AUTHOR]

Hydrothermal liquefaction (HTL) is an emerging method for thermochemical conversion of wet organic waste and biomass into renewable biocrude. HTL also produces an aqueous phase (HTL-AP) side stream containing 2–4% light organic compounds that require treatment. Although anaerobic digestion (AD) of HTL-AP has shown promise, lengthy time periods were required for AD microbial communities to adapt to metabolic inhibitors in HTL-AP. An alternative for HTL-AP valorization was recently demonstrated using two engineered strains of Yarrowia lipolytica, E26 and Diploid TAL, for the overproduction of lipids and the polyketide triacetic acid lactone (TAL) respectively. These strains tolerated up to 10% HTL-AP (v/v) in defined media and up to 25% (v/v) HTL-AP in rich media. In this work, adaptive laboratory evolution (ALE) of these strains increased the bulk population tolerance for HTL-AP to up to 30% (v/v) in defined media and up to 35% (v/v) for individual isolates in rich media. The predominate organic acids within HTL-AP (acetic, butyric, and propionic) were rapidly consumed by the evolved Y. lipolytica strains. A TAL-producing isolate (strain 144-3) achieved a nearly 3-fold increase in TAL titer over the parent strain while simultaneously reducing the chemical oxygen demand (COD) of HTL-AP containing media. Fermentation with HTL-AP as the sole nutrient source demonstrated direct conversion of waste into TAL at 10% theoretical yield. Potential genetic mutations of evolved TAL production strains that could be imparting tolerance were explored. This work advances the potential of Y. lipolytica to biologically treat and simultaneously extract value from HTL wastewater. Key points: • Adaptive evolution of two Y. lipolytica strains enhanced their tolerance to waste. • Y. lipolytica reduces chemical oxygen demand in media containing waste. • Y. lipolytica can produce triacetic acid lactone directly from wastewater. [ABSTRACT FROM AUTHOR]

Nanofiltration (NF) membranes, which can consistently offer safe and reliable water quality, have become increasingly popular in drinking water treatment. In this study, the conventional (coagulation-sedimentation-sand filtration) and ozonation-biologically activated carbon filtration (O3-BAC) advanced treatment processes at a full-scale drinking water treatment plant (DWTP) were combined with a pilot-scale NF process for treatment of Taihu Lake water. The results showed that the "conventional + O3-BAC + NF" combined processes had superior effects on removing natural organic matter (NOM), Br−, and other common water quality parameters (e.g., turbidity, conductivity, TDS, and total hardness) with efficiencies of 88.8–99.8%, for which the NF process played a critical role. The conventional plus O3-BAC processes effectively removed formation potential of chlorinated disinfection by-products (Cl-DBPFPs, by 28.0–46.6%), but had poorer effect in reducing formation potential of brominated DBPs (Br-DBPFPs, by −2637.2–17.3%). NOM concentrations (characterized by dissolved organic carbon (DOC), ultraviolet absorbance at 254 nm (UV254), and/or fluorescent components) were the driving factors for most DBPFP species, while elevation of [Br−]/[DOC] ratio likely resulted in enhanced formation of brominated trihalomethanes (THMs) during chlorination of the BAC effluent. By adding the pilot-scale NF process, the "conventional + O3-BAC + NF" treatment train effectively controlled DBPFP, yielding the removal efficiencies of Cl-DBPFP and Br-DBPFP as 77.6–100% and 33.5–100%, respectively, with monochloroacetic acid, mono-bromo-acetic acid, and tribromomethane formation potentials (MCAA-FP, MBAA-FP, and TBM-FP) not detected in the final effluent. Low temperature in the winter season might be the primary reason for the rapid increase of transmembrane pressure when operating the NF membrane under flux of 25 L/(m2·h), which could be largely delayed by lowering the flux to 20 L/(m2·h). Characterization of the membrane cleaning solutions showed that macromolecular biopolymers (6000 Da–4000K Da) such as polysaccharides and proteins were the main contributors to membrane fouling. [ABSTRACT FROM AUTHOR]

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Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

2,6‐dichloro‐1,4‐benzoquinone (2,6‐DCBQ), as an emerging disinfection by‐product, has been frequently detected in waters, posing potential health risk on public health. Although some studies have pointed out that 2,6‐DCBQ exposure can induce cytotoxicity, limited information is available for underlying mechanism for 2,6‐DCBQ‐induced cytotoxicity. To explore this mechanism, we assessed the levels of reactive oxygen species (ROS), acridine orange (AO) staining, and the mRNA transcriptions of genes (Chk2, Cdk2, Ccna, Ccnb and Ccne) involved in cell‐cycle and genes (p53, bax, bcl‐2 and caspase 3) involved in apoptosis in zebrafish embryo, after exposed to different concentrations (10, 30, 60, 90 and 120 μg/L) of 2,6‐DCBQ for 72 h. Our results indicated that 2,6‐DCBQ exposure induced ROS generation and cell apoptosis, and disturbed the mRNA transcription of genes related to cell cycle and apoptosis in zebrafish embryo. Moreover, we also found that 30 ~ 60 μg/L 2,6‐DCBQ is the important transition from cell‐cycle arrest to cell apoptosis. These results provided novel insight into 2,6‐DCBQ‐induced cytotoxicity. [ABSTRACT FROM AUTHOR]

Copyright of Environmental Science & Technology (10036504) is the property of Editorial Board of Environmental Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Trihalomethanes (THMs) are common disinfection by-products in chlorinated tap waters. They can cause various cancers and non-cancer health hazards. Ingestion, dermal contact, and inhalation are the three exposure routes considered in the THM hazard or risk assessments. Among these, inhalation hazard is generally calculated by assuming the initial concentration as zero. This assumption fails to address the case of continuous or successive showers that can happen in shared showering facilities such as student hostels or gymnasiums. In the present study, the leftover THM concentration from the previous bath was considered to assess the chronic daily intakes (CDI) and hazard index (HI) for successive showers. For this, tap water of a university campus was analyzed to understand the extent of THM exposure at consumer points and the result obtained was used for the hazard assessment. Total THM concentrations varied from 0.51 to 68.9 µg L−1. To address the variability of the model input parameters, 50,000 iterations of Monte Carlo simulation were carried out. Maximum HI values of 7.94E − 02 ± 3.63E − 02, and 6.69E − 02 ± 3.08E-02 were observed for the 1st shower for females and males, respectively. This value increased exponentially up to the 5th shower and thereafter, the value was constant. The methodology followed in the present study successfully determines the risk and hazard of THMs through successive showers. [ABSTRACT FROM AUTHOR]

Ferrate(VI) is a green and efficient water treatment agent for drinking and wastewater. It is widely used in water treatment because it has multi-functional uses such as oxidation, algae removal, disinfection, and adsorption flocculation. It does not cause secondary pollution to the environment. This paper compares ferrate(VI) with other water treatment agents and discusses three methods of preparing ferrate(VI). The removal, adsorption, and control of organic matter, algae, disinfection by-products, and heavy metal ions in water when ferrate(VI) was used as an oxidant, disinfectant, and coagulant were summarized. Ferrate(VI) has some advantages in removing toxic, harmful, and difficult-to-degrade substances from water. Due to the disadvantages of ferrate(VI) such as oxidation selectivity and instability, it is necessary to develop the hyphenated techniques of ferrate(VI). In this review, three hyphenated techniques of ferrate(VI) are summarized: ferrate(VI)–photocatalytic synergistic coupling, ferrate(VI)–PAA synergistic coupling, and ferrate(VI)–PMS synergistic coupling. [ABSTRACT FROM AUTHOR]

Biological activated carbon (BAC) will produce soluble microbial products (SMPs), which affect effluent quality. To clarify the mechanism by which BAC affects effluent water quality, the processes of a drinking water plant in Jiangsu Province were investigated. It was found that during the O3-BAC process, although ozonation could remove dissolved organic matter (DOC) to a certain extent, the DOC increased from 4.44 to 4.47 mg/L after BAC. Dissolved organic matter (DOM) in effluent from different processes was divided into five fractions based on hydrophilicity and hydrophobicity by resin fractionation. Through fluorescence excitation-emission matrix (EEM) spectroscopy combined with DOC analysis, it was found that SMPs are mainly included in transitional hydrophilic neutral (TPIN) fraction, which was the main cause of the DOC increase. Therefore, a new combined process was designed to remove TPIN effectively by coagulation after biological treatment, and found that coagulation had a good removal rate (13.2%) on TPIN. The trihalomethane formation potential (THMFP) of TPIN could be reduced effectively by 44.9% after coagulation. Compared with the old process, the new combined process had a higher removal rate (14.2–30.0%) of DOC, as well as a greater reduction of THMFP (29.0–78.6%) and haloacetic acid formation potential (HAAFP) (46.4–75.3%). This study aims to reveal the mechanism by which SMPs affect effluent water quality and exacerbate health risks, and to propose a solution to provide theoretical support for the design and optimization of drinking water treatment processes. [ABSTRACT FROM AUTHOR]

The dairy industry processes vast amounts of milk and generates high amounts of secondary by‐products, which are still rich in nutrients (high Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD) levels) but contain high concentrations of salt. The current European legislation only allows disposing of these effluents directly into the waterways with previous treatment, which is laborious and expensive. Therefore, as much as possible, these by‐products are reutilized as animal feed material and, if not applicable, used as fertilizers adding phosphorus, potassium, nitrogen, and other nutrients to the soil. Finding biological alternatives to revalue dairy by‐products is of crucial interest in order to improve the utilization of dry dairy matter and reduce the environmental impact of every litre of milk produced. Debaryomyces hansenii is a halotolerant non‐conventional yeast with high potential for this purpose. It presents some beneficial traits – capacity to metabolize a variety of sugars, tolerance to high osmotic environments, resistance to extreme temperatures and pHs – that make this yeast a well‐suited option to grow using complex feedstock, such as industrial waste, instead of the traditional commercial media. In this work, we study for the first time D. hansenii's ability to grow and produce a recombinant protein (YFP) from dairy saline whey by‐products. Cultivations at different scales (1.5, 100 and 500 ml) were performed without neither sterilizing the medium nor using pure water. Our results conclude that D. hansenii is able to perform well and produce YFP in the aforementioned salty substrate. Interestingly, it is able to outcompete other microorganisms present in the waste without altering its cell performance or protein production capacity. [ABSTRACT FROM AUTHOR]

Drinking water treatment plants (DWTP) use chlorination as an oxidation stage in the first step of the processes used to eliminate the natural organic matter (NOM) responsible for the formation of 2-methylisoborneol (2-MIB) and Geosmin (GM), which produce odor and taste to the water. However, chlorination processes give rise to disinfectant toxic subproducts, such as trihalomethanes (THMs). In this work, a headspace solid-phase microextraction coupled with a gas chromatography/mass spectrometric method has been developed for the quality control of drinking water. 2-MIB, GM, and THMs at different stages of the drinking water treatment process were monitored. The method was validated following the Environmental Protection Agency guidelines. Neither carryover nor the matrix effect was observed. The performance of the method was satisfactory in terms of selectivity, repeatability, and accuracy and exhibited a linear concentration range of 0.8–50 µg/L for trichloromethane (TCM), 0.05–20 µg/L for bromodichloromethane, 0.01–20 µg/L for dibromochloromethane and tribromomethane, and 0.005–0.05 µg/L for GM and 2-MIB. The THMs concentration obtained for all the water samples was below the thresholds established by international organizations and, for 2-MIB and GM, were lower for their limit of quantification. The method was also applied to the adsorption kinetic study of TCM on granulated activated carbon, which is the main barrier to reducing the NOM in DWTP. [ABSTRACT FROM AUTHOR]

Trihalomethanes (THMs) are the most common species of disinfection by-products (DBPs) in swimming pools and have received widespread attention due to their risk to public health. However, studies examining within-day variation and the carcinogenic health risks from exposure to THMs in indoor swimming pools are limited. Our study aimed to detect the within-day variation of four THMs categories and carcinogenic health risk in indoor swimming pool water in Taiyuan, China, and to examine the correlations between THMs and environmental parameters. Our results showed chloroform (TCM) was the most abundant component in THMs with median concentrations from 0.038–0.118 μg/m3. TCM and THMs were significantly positively correlated with FCl and significantly negatively correlated with the cumulative number of swimmers (CNS) in the swimming pool. The concentration of total THMs and TCM, lifetime average daily doses (LADD) of TCM, and the total lifetime cancer risks (ELCR) values of THMs declined with time with the highest level occurring at 8:00 am. ELCR values of THMs were in the range of 1.368 × 10−5–1.968 × 10−5, which exceeded the negligible risk level (10−6) defined by US EPA. Our results suggest that THM occurrence and the carcinogenic health risks in pool water varied temporally. Exposure to pool water THMs may pose a carcinogenic risk to human health, especially at the pool's opening time. [ABSTRACT FROM AUTHOR]

Note: Created with BioRender.com. [Display omitted] • B. cereus coexisted with nitrophenols (NPs) could increase Cl-DBPs formation. • B. cereus , UV radiation, chlorine, pH, and nitrophenol influenced Cl-DBPs formation. • Intermediate products formed from B. cereus and nitrophenols were identified. • Formation mechanisms of Cl-DBPs were proposed when B. cereus coexisted with NPs. • B. cereus coexisted with NPs affected Cl-DBPs formation and toxicity in real waters. B. cereus and nitrophenols simultaneously exist in aquatic systems and can produce chlorinated disinfection byproducts (Cl-DBPs) with high toxicity in chlorinated waters. Nevertheless, it has not been reported that B. cereus coexisted with nitrophenols can influence Cl-DBPs formation. Herein, it is the first time investigate the effects of B. cereus coexisted with nitrophenols on chlorinated halonitromethanes (Cl-HNMs), dichloroacetonitrile (DCAN), and trichloromethane (TCM) formation in the sequential UV-chlorine disinfection process. The coexistence of nitrophenols with a low concentration of B. cereus enhanced Cl-DBPs formation but nitrophenols coexisted with a high concentration of B. cereus dramatically inhibited that. Meanwhile, increasing UV fluence, chlorine dose, and nitrophenol concentration in a certain range increased Cl-DBPs formation, and alkaline pH inhibited Cl-HNMs and DCAN formation but favored TCM formation. Besides nitrophenols, the organic matter (e.g., metabolites, soluble microbial byproducts, and intracellular organic matter) produced from B. cereus cells was degraded into small molecules, which could serve as precursors for Cl-DBPs formation. Likewise, nitrophenols could be degraded through the B. cereus pathway and generate Cl-DBPs. Finally, the Cl-DBPs yields and toxicity in different water samples followed the order of real waters > simulated waters in most cases. This study offers a new and deeper understanding of the effects of B. cereus and nitrophenols on Cl-DBPs formation during chlorine-based disinfection and provides experimental references for the sequential UV-chlorine disinfection process application. [ABSTRACT FROM AUTHOR]

[Display omitted] • An eco-friendly Al(III)/S(IV) ARP for ClO 2 − reduction was developed. • Al(III)/S(IV) system rapidly reduced ClO 2 − with decay rates of 0.126 ± 0.009 s−1. • Al3+ and Al(OH)2+ activate HSO 3 − to generate sulfite radicals as reducing species. • Cl− was the primary Cl-containing product in Al(III)/S(IV) system. • ClO 2 − decay was efficient in practical waters, meeting the Drinking Water Standard. Advanced reduction processes (ARPs) hold the potential for fast reducing chlorite (ClO 2 −), a harmful by-product of chlorine dioxide (ClO 2) disinfection. In this study, we developed aluminum(III)/sulfite (Al(III)/S(IV)) ARPs for reduction of chlorite from drinking water. The Al(III)/S(IV) system exhibited a fast removal of 13.5 mg/L ClO 2 − within one min by 1.4 mg/L Al(III) and 80 mg/L S(IV), with a first-order rate constant of 0.126 ± 0.009 s−1. The removal rate constant was up to over two orders of magnitude faster than previous studies. Reduction of chlorite was further enhanced by increasing Al(III) and S(IV) dosage, and decreasing solution pH and dissolved oxygen levels. The electron paramagnetic resonance spectra and mass balance of chlorine revealed that sulfite radicals generated through HSO 3 − activation with Al3+ and Al(OH)2+ were responsible for chlorite reduction to chloride. Pathways for chlorite reduction were proposed accordingly. Moreover, the presence of organics and some anions (i.e., 0.5–1.0 mM Cl− and NO 2 −) and cations (i.e., 0.5–1.0mM K+ and Na+) little influenced chlorite reduction, while the addition of 0.5–1.0 mM HPO 4 2−, HCO 3 −, Ca2+, and Mg2+ inhibited the reduction. Under realistic conditions relevant to water plants using ClO 2 disinfection, >72.1 % of 1.4 mg/L chlorite was reduced in one min with a lower electrical energy per order (EE/O = 1.78 ± 0.10 kWh/m3), meeting the Drinking Water Standard for both residue chlorite (<0.7 mg/L) and aluminum levels (<0.2 mg/L). Collectively, Al(III)/sulfite system is promising for fast, complete, and cost-effective reduction of oxyanions including chlorite in filter effluents from drinking water plants. [ABSTRACT FROM AUTHOR]

• More objective and comprehensive verification of the self-adaptive capacity of fine bubbles to force the hydrolysis of PACl. • A reasonable elaboration of the evolution of dominant Al species during forced hydrolysis by fine bubbles. • Innovative construction of the relationships between the characteristics of fine bubbles and their forcing PACl hydrolysis efficiency and capacity. • Preliminary validation of the correlation and feasibility between forced PACl hydrolysis by fine bubbles and enhanced coagulation efficiency. Enhanced coagulation is an important way to remove natural organic matter and reduce disinfection by-products in traditional water treatment processes, in which the micromolecular organic matter that is difficult to be removed during conventional coagulation can be enhanced more conveniently by modulating the dominant Al species in the traditional metal salt coagulants (e.g., polymeric aluminum chloride, PACl). Based on the forcing hydrolysis characteristics of fine bubbles due to the adsorption of hydroxide ions on their surfaces, this study verified the adaptability of the forced PACl hydrolysis by fine bubbles under different operating conditions objectively and comprehensively. The morphological changes of PACl before and after forced hydrolysis by fine bubbles were characterized figuratively, and the evolution of the dominant Al species before and after forced hydrolysis by fine bubbles was reasonably elaborated. The experimental results showed that fine bubbles had the effect of forcing the hydrolysis of PACl with different degrees of alkalinity and modulating the dominant Al species. It was innovatively found that the mass transfer efficiency of the fine bubbles determined their efficiency in forcing PACl hydrolysis (Pearson's r = -0.9423) and the concentration of fine bubbles affected their capacity to force PACl hydrolysis (Pearson's r = 0.8189). At pH = 7 and an air flow rate of 20 mL/min, the DOC concentration of micromolecular organics and the DOC removal efficiency of total organics could be reduced by 0.54 mg/L and enhanced by 12.6 %, respectively, after forced PACl hydrolysis by fine bubbles. While deepening the mechanism of forced PACl hydrolysis by fine bubbles, the above results preliminarily verified the relevance and feasibility of modulating the dominant Al species through forced PACl hydrolysis by fine bubbles to improve the coagulation efficiency, which provided theoretical and data support for the construction of a fine bubble-enhanced coagulation process for drinking water treatment plants. [Display omitted] [ABSTRACT FROM AUTHOR]

This study investigated the presence of mutagenic compounds in raw and treated waters at four water treatment plants (WTP01 to WTP04), in southern Brazil. Samples were concentrated using Amberlite XAD4 resin and the acidic and neutral pH fractions tested by mutagenesis in Salmonella /microsome assay, using TA98, TA100 and YG7108 strains in presence and absence of metabolic activation (in vitro human S9). Mutagenesis in raw water was found only by strain TA98 at WTP03, with and without S9. In treated water, significant results were found for TA98 and TA100 strains, the latter being the most sensitive, with prevalence in acidic extract tests without S9. A chemical analysis was performed in the water samples, prioritizing the investigation of the presence and concentration of globally used Emerging Micropollutants (EMs). These compounds in water sources have the potential to contaminate drinking water due to the inefficiency of the conventional treatment employed and can generate disinfection by-products. WTP04 site had the highest total EMs in raw and treated waters, followed by WTP03 in treated water. These WTPs expressed an EMs removal capacity of 45% and only 23%, respectively. Some pharmaceuticals and caffeine showed the highest concentrations, and the latter was directly related to the disposal of domestic sewage in the aquatic ecosystem. The presence of EMs in water after treatment for all WTPs investigated suggests the importance of expanding guidelines that include EMs to establish better standards for the protection of aquatic life and better quality of the drinking water supplies. [Display omitted] • Absence of mutagenesis in water organic extracts as environmental quality marker. • Presence of mutagenic potential pollutants in raw and drinking water. • Reduction of micropollutants in treated water compared to raw water. • Human S9 reduced the mutagenic activity in treated water samples. • Patterns of mutagenesis suggest formation of unknown DBPs. [ABSTRACT FROM AUTHOR]

• BrCl instead of HOBr dominates benzotriazoles degradation during seawater chlorination. • BrCl reacts with benzotriazole at a rate constant 30,000 times higher than HOBr. • Ten brominated products including mono-, di-, and tribrominated derivatives were identified. • BrCl significantly increases the generation and toxicity of brominated products. A common understanding attributes the formation of brominated disinfection by-products (Br-DBPs) in seawater chlorination to the conversion of hypochlorous acid to hypobromous acid (HOBr) by bromide. In this study, we reveal that bromine chloride (BrCl), mediated by both chloride and bromide in seawater, plays a dominant role in the transformation of 1H-benzotriazole (BTA) and 5-methyl-1H-benzotriazole (MBTA) and in the formation of brominated DBPs. Using anisole as a reference compound, the second-order rate constant for the reaction of BrCl with BTA was determined to be (2.65 ± 0.13) × 105 L mol−1 s−1, which is over 30,000 times higher than that for the reaction between HOBr and BTA. Ten brominated products were identified and showed a successive bromination pattern. The bromination reaction mechanism was elucidated through theoretical calculations, and the pathways were proposed. The concentrations of brominated BTA and MBTA in seawater were 5.7 and 7.9 times higher than in bromide-only solutions, respectively. BrCl significantly promoted brominated product generation and increased the toxicity of blended DBPs. These results suggest that focusing solely on bromide's effect on brominated product generation may significantly underestimate the potential for DBP formation during seawater chlorination. [Display omitted] [ABSTRACT FROM AUTHOR]

In recent years, halogenated carbazoles (HCZs) have emerged as a novel class of disinfection byproducts (DBPs) detected in tap water, posing potential dioxin-like toxicity risk to human health. Therefore, it is particularly important to detect HCZs in tap water, yet this process is time-consuming and labor-intensive. To address this challenge, developing predictive models for HCZs based on water quality parameters presents an attractive alternative. Unfortunately, no prediction studies for HCZs have been reported to date. This study investigated the feasibility of using linear models, log-linear models, backpropagation neural networks (BPNN), general regression neural networks (GRNN), and radial basis function neural networks (RBFNN) to predict the occurrence of HCZs, including 3-chlorocarbazole (3-CCZ), 3-bromocarbazole (3-BCZ) and total halogenated carbazoles (ΣHCZs) in tap water. The input parameters for BPNN, GRNN, and RBFNN were selected based on grey relational analysis (GRA) results, while the linear and log-linear models were developed using stepwise regression. The results showed that linear and log-linear models were not suitable (N 25 = 0.30–0.64, r p = 0.40–0.71), and BPNN demonstrated limited prediction performance (N 25 = 0.52–0.78, r p = 0.77–0.83). GRNN excelled only in predicting ΣHCZs (N 25 = 0.98, r p = 0.96). Particularly, RBFNN exhibited good performance in predicting 3-CCZ, 3-BCZ, and ΣHCZs (N 25 = 0.70–0.89, r p = 0.89–0.94), providing valuable insights and possibilities for real-time monitoring of HCZs in tap water. [Display omitted] • This is the first study on the prediction of HCZs levels in tap water. • Linear/log-linear models are not suitable for the prediction of HCZs. • The predictive capability of BPNN for HCZs levels is limited. • GRNN only performed well in predicting ΣHCZs. • RBFNN can effectively predict 3-CCZ, 3-BCZ and ΣHCZs. [ABSTRACT FROM AUTHOR]

Biochar is a carbon-rich, sponge-like material with intricate functionalities, making it suitable for various environmental remediation applications, including water treatment, soil amendment and, additives in construction materials, anaerobic digesters, and electrodes, among others. Its easy adaptability and low cost make it particularly attractive. This review highlights a range of biochar and surface-modified biochar exhibiting high uptake and degradation efficiencies for a broad spectrum of contaminants, including humic acid, disinfection by-products (DBPs), radioactive materials, dyes, heavy metals, antibiotics, microplastics, pathogens, Per- and polyfluoroalkyl substances (PFAS), and cytotoxins. The study provides a detailed discussion on different classes of pollutants and their removal mechanisms using biochar, covering processes like physical and chemical adsorption, electrostatic interactions, π-π interactions, hydrogen bonding, as well as surface complexation, chelation, among others. This review article stands out for its comprehensive exploration of biochar's effectiveness in removing a wide range of emerging contaminants, as well as recent advancements in the removal of conventional pollutants like heavy metals and antibiotics. [Display omitted] • Summarizes up to date findings on biochar application in contaminated water treatment. • Reviews biochar characteristics influencing pollutant removal from contaminated water. • Comprehensive coverage of traditional to emerging pollutants removal efficiency of biochar. • Regeneration and reusability of biochar based adsorbents are discussed. • Looks at techno-economic and life cycle assessment of biochar use for water remediation. • Identified key challenges and research needs in biochar application for pollutants remediation. [ABSTRACT FROM AUTHOR]

In this study, a novel process of dielectric barrier discharge (DBD)/chlorine for levofloxacin (LEV) degradation was investigated. The combined system boosted the degradation efficiency of LEV from 77.8% to 97.5%, improved the reaction rate constant by 2.3 times, and reduced energy consumption by 64.5%. DBD/chlorine process was highly efficient for LEV degradation across a pH range of 3.3–10.8, with removal rates varying from 90.3% to 97.5%. The electron paramagnetic resonance and scavenging experiments demonstrated the generation of reactive oxygen species (ROS, including HO•, 1O 2 , and O 2 • – ) and reactive chlorine species (RCS) in the DBD/chlorine system, with 1O 2 in the nonradical pathway being crucial for LEV removal. Crucially, effective activation of chlorine not only encouraged the production of reactive species but also prevented the formation of disinfection by-products (DBPs), successfully controlling the ecotoxicity of the reaction system. DBD could activate chlorine to form chlorate and HO•, which in turn triggered the production of RCS. The comparison of the LEV degradation pathway was proposed with or without chlorine in the DBD process. Finally, the effects of different water quality and water bodies demonstrated the application prospects of the DBD/chlorine process. This work provided an efficient technique for the elimination of antibiotics by non-thermal plasma/chlorine. [Display omitted] • Chlorine significantly improved LEV degradation in the DBD process. • Chlorine boosted the production of reactive chlorine/oxygen species in the DBD process. • 1O 2 -dominated non-radical pathways played a crucial role in the DBD/chlorine system. • The combined system reduced LEV toxicity and controlled DBPs formation. [ABSTRACT FROM AUTHOR]

Algal organic matter (AOM) originating from cyanobacteria-impacted reservoirs presents a significant risk to drinking water. Electrochemical oxidation is an emerging technology effective in AOM degradation. This study focuses on the elimination of AOM, including extracellular organic matter (EOM) and intracellular organic matter (IOM), extracted from Microcystis aeruginosa (MA). Electro-Fenton (EF) and electro-oxidation (EO) techniques were used, with a boron-doped diamond (BDD), a modified graphene-Fe 2 O 3 (GFe) anode, and a graphite felt (GF) cathode. The results showed that BDD and GFe electrodes can effectively degrade AOM, particularly IOM, via EO and EF. BDD with high overpotential exhibited significant IOM degradation via EF, where dissolved organic carbon reduction reached up to 85%. In EO reactions, H 2 O 2 generation by GFe-30 (obtained at the optimal ferric oxide to graphene ratio) is slightly higher than that in BDD, but it cannot fully transform into •OH in the EF process, which inhibits its AOM degradation capability. Furthermore, soluble microbial product-like substances and humics are more effectively degraded by EF and EO using either BDD or GFe. High-molecular weight (>103 Da) fractions, such as biopolymers and humic substances, are principally degraded by both EF and EO regardless of the BDD and GFe anode. This process leads to significant reductions in the haloacetic acids (HAAs) formation potential. EO and EF with GFe-30 are more effective in reducing specific disinfection by-product formation potential during IOM suspension degradation compared to BDD. In conclusion, GFe serves as a novel electrode material to replace BDD as a potent carbon-based anode when utilizing EO or EF treatments for effective AOM removal from cyanobacteria-infested water for drinking water treatment. • The EO and EF with either BDD or GFe-30 electrode is powerful to degrade IOM at pH 3. • SMPL and humic substances are mostly degradable by EF and EO with BDD or GFe-30. • EO and EF with BDD or GFe-30 favour reducing high-MW (>103 Da) fractions and HAAFP. • GFe-30 is superior to lower the specific DBPFP of IOM compared to BDD in EO and EF. [ABSTRACT FROM AUTHOR]

[Display omitted] • The reactive sites of the pollutant were predicted. • The reaction mechanisms and kinetics of pollutant were explored. • The effects of reaction conditions on degradation efficiency were investigated. • The aquatic toxicity of each degradation product was assessed. In this study, the reaction mechanisms and kinetics in the degradation of chlorophenylacetonitrile (2-CPAN) by the UV/H 2 O 2 process were investigated by the theoretical calculation method. A chemical kinetic model was developed to simulate the degradation efficiency of 2-CPAN during the degradation process. In addition, the toxic effects of 2-CPAN and its products on the aquatic environment were assessed. During the initial reactions, the hydrogen atom abstraction reactions of the branched chain was more likely to occur than the ·OH-addition reactions. Kinetic results showed that the total second-order reaction rate increased with increasing temperature in the range of 273–313 K, and the total second-order reaction rate was 5.69 × 107 M−1 s−1 at 298 K. The results of degradation efficiency simulation showed that high concentration of oxidant, long reaction time, low initial concentration of pollutant, and low pH were favorable for improving the degradation efficiency. Toxicity assessment showed that most of the degradation products were less toxic to aquatic organisms than 2-CPAN. A theoretical guidance for the chemical reaction characteristics and kinetic behaviors for the degradation of disinfection by-products by the UV/H 2 O 2 process was provided in this study. [ABSTRACT FROM AUTHOR]

[Display omitted] • Resazurin was used as a probe for rapid and accurate detection of HOBr in the water environment. • The probe showed excellent selectivity, high sensitivity and fast response for HOBr. • The generation of HOBr in chlorination disinfection and PMS-degradation was successfully tracked. • Test strips were prepared to detect HOBr conveniently and quickly. The highly reactive hypobromous acid (HOBr), which is generated after chlorination process of tap water, acts as a precursor of toxic brominated disinfection by-products (Br-DBPs) and further reacts with organic matter. In addition, HOBr produced from the oxidation of Br− during the degradation of pollutants by peroxymonosulfate (PMS, HSO 5 −) can be considered as the cause of the expedited degradation of pollutants. Therefore, it is particularly important to detect HOBr level in the water environment. Resazurin was selected as a fluorescent probe for selective recognition of HOBr in the water environment. The probe exhibited excellent spectral performance and showed high sensitivity to HOBr (LOD = 515 nM). This method has a relatively ideal recovery rate for HOBr detection in environmental water samples. Furthermore, the HOBr production during the chlorination disinfection process was simulated and the HOBr generated from this process was detected by the probe. Importantly, the process of HOBr recognition by the probe is accompanied by the change of color. Based on this, the relationship between the change of color B/G value and HOBr concentration was successfully constructed. The probe was loaded on the filter paper to make a test strip, which was utilized to the detection of HOBr. Collectively, this work provided a promising and powerful method for HOBr detection in the environment. [ABSTRACT FROM AUTHOR]

2,6-Dibromo-1,4-benzoquinone (2,6-DBBQ) and 2,6-dichloro-1,4-benzoquinone (2,6-DCBQ), two emerging halobenzoquinones (HBQs), have the highest detection frequencies and levels in drinking water among all HBQs. They are more toxic than the regulated disinfection byproducts. Quantitative structure toxicity relationship analysis predicted that HBQs are a class of potential bladder carcinogens. However, direct experimental evidence for the carcinogenicity of 2,6-DBBQ and 2,6-DCBQ is lacking and the associated toxicity mechanisms remain unclear. In this study, we confirmed the potential carcinogenicity of 2,6-DBBQ and 2,6-DCBQ using an in vitro malignant transformation assay, evaluated their cytotoxicity and genotoxicity, and investigated their toxicity mechanisms. The results showed that 2,6-DBBQ and 2,6-DCBQ significantly decreased the viability of human uroepithelial SV-HUC-1 cells and induced DNA damage in SV-HUC-1 cells, and chromosomal damage in HepG2 cells, and malignant transformation of SV-HUC-1 cells. Moreover, transcriptome sequencing revealed that 2,6-DBBQ and 2,6-DCBQ activated the p53 -mediated cell cycle pathway in bladder cancer. In the p53 -mediated cell cycle pathway, 2,6-DBBQ and 2,6-DCBQ induced cell cycle arrest at the S phase by downregulating p53 and upregulating p21. Additionally, 2,6-DBBQ and 2,6-DCBQ may have produced excessive reactive oxygen species, damaging DNA and chromosomes. These results not only first confirm the potential carcinogenicity of 2,6-DBBQ and 2,6-DCBQ but also provide an important reference for exploring the cytotoxicity and genotoxicity mechanisms of these HBQs. [Display omitted] • 2,6-DBBQ and 2,6-DCBQ displayed cytotoxicity and genotoxicity. • 2,6-DBBQ and 2,6-DCBQ had potential carcinogenicity. • The activation of the p53 -mediated cell cycle pathway was involved in HBQ toxicity. • 2,6-DBBQ and 2,6-DCBQ induced excessive ROS to damage DNA and chromosomes. [ABSTRACT FROM AUTHOR]

Tissue deterioration and post-injury infections are the primary cause of skin diseases. Tissue engineering has developed various synthetic and natural polymers to generate bioactive scaffolds that can closely replicate the natural extracellular matrix (ECM). Decellularized tissues have emerged as a potential solution for reconstructing cutaneous lesions due to their ability to preserve the intricate protein structure and provide essential functional domains for cellular differentiation. In this study, we selected bovine pericardium and subjected it to diverse decellularization methods to optimize ECM preservation. Polyvinyl alcohol (PVA)/chitosan (CS) infused with two clinically important antibiotics (colistin and meropenem) was directly electrospun onto the decellularized bovine pericardium (DBPS) to endow the dual-layer scaffold (DBPS-Abs) an antibacterial property. Both DBPS-Abs and DBPS demonstrated a consistent 3D microstructure with interlinked pore networks, minimal degradation, and robust mechanical stability. The DBPS-Abs group exhibited a potent antibacterial effect against standard and clinical strains of Escherichia coli. Moreover, implanting the constructs into full-thickness skin wounds in mice confirmed enhanced wound regeneration in cases treated with DBPS-Abs compared to other groups, observed over a 7- and 21-day post-implantation period. These findings highlight DBPS-Abs as a superior antibacterial wound dressing, requiring further clinical evaluations. [ABSTRACT FROM AUTHOR]

The investigations into the existence and behavior of microplastics (MPs) in water environment were widely conducted, while the characteristics of dissolved organic matter derived from MPs (MPs-DOM) during advanced oxidation have garnered comparatively little attention. In this study, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) was employed along with multiple statistical analyses to gain a deeper understanding of the conversion of MPs-DOM in UV/chlor(am)ine advanced oxidation processes (AOPs). The diverse treatments exhibited varying degrees of augmentation in both aging and fragmentation of MPs with the order of UV/Cl 2 > UV > UV/NH 2 Cl. The fragmentation degree of MPs upon two UV-based AOPs (UV-AOPs) was dependent on their monomer chemical structure. The highest TOC values of three MPs-DOM were observed after UV/Cl 2 AOP and the lowest after UV/NH 2 Cl AOP. Polyvinyl chloride (PVC) displayed a greater release of MPs-DOM under varying leaching conditions. UV/Cl 2 AOP favored the reaction with saturated MPs-DOM, while UV/NH₂Cl AOP reduced unsaturated MPs-DOM, alleviating disinfection byproducts (DBPs) formation after chlorination. The precursors generated by UV/Cl₂ AOP owned lower H/C, higher modified aromatic index (AI mod), and lower molecular weight (MW) products after chlorination. PVC-DOM with fewer CH₂ groups was more reactive. -H₂O, +O and -CH₂ reactions dominated in PVC-DOM (CHO compounds), while -2H, +O, -CH₂ did in PVC-DOM (CHON compounds). The dominant chlorine addition/substitution reactions occurred in PVC-DOM treated by UV/Cl₂ AOP, identifying 195 Cl-DBPs with 220 precursor-product pairs. Mass difference analyses showed that +2H and +O reactions were the most frequent of the 24 reaction types. [Display omitted] • Changes of over 3000 MPs-DOM features by UV/Cl 2 and UV/NH 2 Cl AOPs were examined. • UV/Cl₂ primarily reacted with saturated MPs-DOM, producing more unsaturated MPs-DOM. • UV/NH₂Cl reduced unsaturated MPs-DOM, alleviating DBPs after chlorination. • The reaction involved in two UV-AOPs were deciphered based on 24 reactions types. • Connections between Cl-DBPs and their precursors were built by MDiNs computation. [ABSTRACT FROM AUTHOR]

This study systematically investigated the direct activation of chlorine by visible light emitting diode (Vis-LED). Vis-LED could effectively activate chlorine to degrade micropollutants with degradation efficiency and pseudo-first-order degradation rate constant range of 64.3–100 % and 0.0340–0.195 min−1, respectively. Quenching experiments and modeling results suggested that reactive chlorine species (RCS, including ClO•, Cl 2 •-, and Cl•) and hydroxyl radical (•OH) were involved in the degradation of atenolol (ATL). The contribution ratio of ClO•, free available chlorine, Cl•, Cl 2 •-, and •OH to ATL degradation were 58.7 %, 17.4 %, 15.6 %, 1.8 %, and 5.9 %, respectively, in Vis-LED 448 /chlorine process. Moreover, the innate quantum yields of HClO and ClO- decreased from 0.229 and 0.0206 to 0.0489 and 0.0109 mol·Einstein−1, respectively, as the wavelength increased from 448 to 513 nm, leading to a decrease in ATL degradation, which was consistent with the model results. Experimental and modeling results have confirmed that ATL degradation decreased when pH increased from 4.0 to 9.0. Cl- had little effect on the degradation of ATL, while HA and HCO 3 - affected ATL degradation by scavenging reactive species and/or shielding effect. The concentration of disinfection by-products decreased with the increase of wavelength and pH. In summary, Vis-LED/chlorine is an efficient water treatment process even without a catalyst. [Display omitted] • Visible light can effectively activate chlorine to degrade organic micropollutants in water. • The innate quantum yield of chlorine decreased with the increase of visible light wavelength and pH. • ClO• was the major contributor to ATL degradation in the pH range of 4.0-9.0. • The increase of pH enhanced the contribution of ClO•. [ABSTRACT FROM AUTHOR]

The reuse of reclaimed wastewater is increasingly recognized as a viable alternative water source for irrigation. Its application, whether direct or indirect, impacts several interconnected compartments, including groundwater, surface water, soil, crops, and humans. Reclaimed wastewater provides essential resources for crops, like water and nutrients. However, it also introduces pathogens, and contaminants of emerging concern (CECs), defined as chemicals that may pose risks to human health and ecosystems but are not yet fully regulated, such as pharmaceuticals and personal care products, among others. Additionally, reclaimed wastewater may contain antibiotic-resistant bacteria (ARBs) and disinfection by-products (DBPs), all of which present potential health and environmental risks. Therefore, regulatory bodies stress the need for preventive risk assessments to ensure safe reuse. This paper critically reviews available models for assessing the impacts of reclaimed wastewater reuse in agriculture. It identifies gaps in current modelling approaches and outlines future research directions. Key areas requiring further investigation include the fate and transfer of CECs, ARBs and DBPs, and the co-occurrence of multiple risks in such interconnected systems, especially in the indirect reuse. To address these gaps, we proposed a simplified approach to integrate three types of risk associated with CECs in indirect reuse, focusing on risks posed by antibiotics and other pharmaceuticals: human health risk, environmental risk and risk from antibiotic resistance development. This approach aids in identifying the most critical endpoints within the One Health approach, supporting (i) CECs prioritization in regulations based on their critical endpoints and (ii) the adoption of CEC-specific mitigation measures. [Display omitted] • This work reviews available models for assessing reclaimed wastewater reuse impacts. • Gaps and future research directions in reuse impacts modelling are identified. • There is a lack of application of integrated risk assessments to wastewater reuse. • A new integrated human, environmental and antimicrobial risk assessment is proposed. • One Health approach allows risk-based regulation and management of wastewater reuse. [ABSTRACT FROM AUTHOR]

Effective disinfection is essential for maintaining water quality standards in distribution networks. Chlorination, as the most used technique, ensures safe water by maintaining sufficient chlorine residuals but also leads to the formation of disinfection byproducts (DBPs). These DBPs pose health risks, highlighting the need for chlorine injection control (CIC) by booster stations to balance safety and DBPs formation. Prior studies have followed various approaches to address this research problem. However, most of these studies overlook the changing flow conditions and their influence on the evolution of the chlorine and DBPs concentrations by integrating simplified transport-reaction models into CIC. In contrast, this paper proposes a novel CIC method that: (i) integrates multi-species dynamics, (ii) allows for a more accurate representation of the reaction dynamics of chlorine, other substances, and the resulting DBPs formation, and (iii) optimizes for the regulation of chlorine concentrations subject to EPA mandates thereby mitigating network-wide DBPs formation. The novelty of this study lies in its incorporation of time-dependent controllability analysis that captures the control coverage of each booster station. The effectiveness of the proposed CIC method is demonstrated through its application and validation via numerical case studies on different water networks with varying scales, initial conditions, and parameters. • Disinfection byproduct (DBP) formation from chlorine injections poses health risks. • We develop spatiotemporal advection–dispersion–reaction model of (de)contaminants. • Near real-time chlorine injections are computed under varying network conditions. • Case studies reveal that optimized injections reduce DBP formation and health risks. [ABSTRACT FROM AUTHOR]

Bromate (BrO 3 -)-induced pharmaceutical and personal care products (PPCPs) oxidation is enhanced in freezing systems. Reduced forms of metals are widely present, often coexisting with various contaminants. However, their effects on the interaction of PPCPs with BrO 3 - in ice in cold regions may have been overlooked. Herein we investigated the effects of representative reducing metal Cr(III) on the interaction between the representative PPCP carbamazepine (CBZ) and BrO 3 - in the freezing system. Our findings demonstrated that the degradation rate constants of CBZ by BrO 3 - and Cr(III) were 29.4%–60.3% lower than those by BrO 3 - in ice, revealing the inhibition of Cr(III) on CBZ degradation by BrO 3 - in ice. In BrO 3 - /freezing/sunlight system, BrO 3 - contributed 62.8% to CBZ degradation. In BrO 3 - /Cr(III)/freezing/sunlight system, Cr(III) promoted the generation of hydroxyl radical (·OH), leading to 51.0% contribution of ·OH to CBZ degradation. Oxidants were consumed by Cr(III) to form Cr(VI) rather than reacting with CBZ, thereby decreasing CBZ degradation by BrO 3 - in ice. Due to sunlight-induced Cr(VI) reduction in ice, only 0.3% of Cr(III) was converted to Cr(VI) in BrO 3 - /Cr(III)/freezing/sunlight system. BrO 3 - -induced CBZ degradation rate in ice decreased in order of Fe(II), Cr(III), and Mn(II), which was due to the different reducing capabilities. An effective reduction in comprehensive toxicity of systems followed the freezing-sunlight process, even in the presence of Cr(III). This work sheds new light on the environmental behaviors and fate of PPCPs, brominated disinfection by-products, and reducing metals during seasonal freezing. [Display omitted] • Cr(III) inhibited 29.4%–60.3% carbamazepine degradation by BrO 3 – in ice. • BrO 3 – and ·OH contributed degradation without and with Cr(III), respectively. • Inhibition of degradation was attributed to the formation of Cr(VI). • Carbamazepine degradation by BrO 3 – decreased in order of Fe(II), Cr(III), Mn(II). • An effective reduction in system toxicity followed the freezing-sunlight process. [ABSTRACT FROM AUTHOR]

The removal of algal organic matter (AOM) through water treatment processes is a major approach of reducing the formation of disinfection by-products (DBP). Here, the formation of DBP from AOM in karst water under different combination of potassium permanganate (KMnO 4) and polyaluminium chloride (PACl) was investigated. The effect of divalent ions (Ca2+ and Mg2+) on DBP formation was traced by AOM chemistry variations. For DBP formation after KMnO 4 preoxidation, total carbonaceous DBPs (C-DBPs) decreased by 12.9% but nitrogen-containing DBPs (N-DBPs) increased by 18.8%. Conversely, the C-DBPs further increased by 3.3% but N-DBPs reduced by 10.7% after the addition of PACl besides KMnO 4 preoxidation. The variations of aromatic protein-like, soluble microbial products-like compounds and ultraviolet absorbance at 254 nm (UV 254) were highly correlated with the formation of DBPs, which suggest aromatic substances strongly affect DBP behaviors at different treatment conditions. In the presence of divalent ions (Ca2+ = 135.86 mg/L, Mg2+ = 18.51 mg/L), the combination of KMnO 4 and PACl was more effective in controlling DBP formation compared to the situation without Ca2+ and Mg2+. Specifically, trichloromethane formation was largely inhibited compared to the other tested DBPs, which may refer to complexation of electron-donating groups via divalent ions. While Ca2+ and Mg2+ may not affect the nature of α-carbon and amine groups, so the variation of haloacetonitriles (HANs) was not obvious. The study enhances the understanding of the DBP formation patterns, transformation of carbon and nitrogen by preoxidation-coagulation (KMnO 4 -PACl) treatment in algae-laden karst water. [Display omitted] • DBP formation was investigated by KMnO 4 and PACl in algae-laden karst water • PACl addition after KMnO 4 inhibited N-DBP formation rather than C-DBPs • Aromatic substances in AOM strongly affect DBP behaviors • Ca2+ and Mg2+ inhibited TCM formation by complexing electron-donating groups [ABSTRACT FROM AUTHOR]

A biochar-supported Ni0/Co0/MnO composite catalyst was prepared from the cathode material (CM) of spent ternary 523 lithium-ion batteries (LIBs) and buckwheat hulls. The effect of pyrolysis temperature (x) and different loading ratios (y) of xBC y CM on the activation of peroxymonosulfate (PMS) was investigated. The results showed that the loading of Ni0/Co0/MnO on the biochar (BC) enhanced the IPM degradation and effectively reduced metal ions' leaching. The 850BC 10 CM/PMS system degraded iopamidol (IPM) within the wide pH range of 5.0–10.0. The pseudo-first reaction rate constant k obs was 0.0944 min−1 during 25 min under optimal conditions (catalyst dose of 0.1 g·L−1, 0.5 mM of PMS, and an initial pH value of 10.0), while the leaching concentrations of Ni, Co, and Mn were 0.089, 0.035, and 0.067 mg·L−1, respectively. Furthermore, the 850BC 10 CM degraded IPM by radicals (· OH, SO 4 •−, and · O 2 -) and non-radical pathways (1O 2 and an electron transfer). As the pH value increased from 7.0 to 10.0, the fluorescence analysis and quenching experiments revealed a decrease in the effects of SO 4 •− and · OH, while the effect of 1O 2 was enhanced. The 850BC 10 CM could still achieve a removal rate of 86.6 % for IPM after four cycles. Based on the liquid chromatography-mass spectrometry (LC-MS) results of degradation intermediates, five possible degradation pathways were proposed. The 850BC 10 CM inhibited the formation of the iodoform CHI 3. In short, the 850BC 10 CM, which was prepared by using a green, sustainable development of waste utilization, exhibited a safe and effective performance for the removal of emerging IPM pollutants. [Display omitted] • The composite catalyst was fabricated from spent LIBs and buckwheat hulls. • BC acted as a carrier of Ni0/Co0/MnO, while reducing the leaching of metal ions. • 850BC 10 CM effectively inhibited the formation of CHI 3. • The effect of 1O 2 increased as the initial pH changed from 7.0 to 10.0. [ABSTRACT FROM AUTHOR]

Eutrophication events in water bodies result in the release of algal organic matter, which is an essential precursor for halonitromethanes during disinfection, posing a significant threat to water quality. During UV/chlorine disinfection, the presence of bromide ion (Br−) promotes the formation of brominated halonitromethanes (Br-HNMs), which exhibit higher toxicity compared to chlorinated halonitromethanes. Nevertheless, limited studies have been conducted on the Br-HNMs formation from algal precursors during UV/chlorine disinfection in the presence of Br−. Therefore, in this study, the formation pattern and toxicity variation of Br-HNMs from the intracellular organic matter (IOM) of anabaena during UV/chlorine disinfection was investigated. The results showed that monobromonitromethane, bromochloronitromethane, and bromodichloronitromethane could be detected during UV/chlorine disinfection. When the Br− concentration raised, the total concentration and toxicity of Br-HNMs exhibited an increase followed by a decline. Additionally, the concentration and toxicity of three Br-HNMs were promoted by increasing UV intensity, free chlorine dosage, and anabaena concentration but inhibited by increasing pH. Based on the experiment results, possible pathways for Br-HNMs formation from anabaena IOM in the presence of Br− were deduced. Moreover, anabaena IOM could also be converted to Br-HNMs during UV/chlorine disinfection of actual water, with a formation pattern similar to that found in distilled water. This research offers valuable insights into Br-HNMs formation from algal-containing waters. [Display omitted] ● During UV/chlorine disinfection involving Br−, anabaena IOM can be converted to Br-HNMs. ● Concentration and toxicity of Br-HNMs raised and then declined with increasing Br−. ● UV intensity, chlorine dosage, anabaena concentration, and pH affect Br-HNMs formation. ● The possible formation pathways of Br-HNMs from anabaena IOM were deduced. ● The formation law of Br-HNMs from anabaena in actual and simulated water were similar. [ABSTRACT FROM AUTHOR]

2,6-Dichloro-1,4-benzoquinone (2,6-DCBQ) is a disinfection by-product (DBP) formed during the disinfection of drinking water. Due to its frequent detection and high concentrations, it has garnered significant attention. However, the effects of 2,6-DCBQ on oocyte meiosis remain poorly understood. In this study, we demonstrate that 2,6-DCBQ exposure disrupts nuclear maturation in oocytes by damaging the spindle and chromosome structure. Additionally, exposure to 2,6-DCBQ impairs cytoplasmic maturation by altering actin dynamics, disrupting cortical granule distribution, and compromising the function of key organelles, including the mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosomes. Supplementing melatonin during meiotic maturation reverses these effects, enhancing organelle function, reducing reactive oxygen species (ROS) levels, alleviating DNA damage, and inhibiting apoptosis. Together, these findings show that 2,6-DCBQ causes organelle dysfunction and meiotic disruption in oocytes, while melatonin provides protective effects against these disruptions during meiotic maturation. [Display omitted] • 2,6-DCBQ exposure impaired oocyte maturation and fertilization capacity. • Melatonin restored the nuclear and cytoplasmic maturation in 2,6-DCBQ-exposed oocyte. • Melatonin enhanced sperm binding and fertilization potential of 2,6-DCBQ-exposed oocytes. • Melatonin ameliorated the dysfunction of ER, Lysosomes, and Golgi apparatus caused by 2,6-DCBQ exposure. • Melatonin strengthened mitochondrial function and reduced ROS-induced apoptosis in 2,6-DCBQ-exposed oocytes. [ABSTRACT FROM AUTHOR]

Algal bloom contribute substantially to dissolved organic matter (DOM) and disinfection by-product (DBP) precursors in deep reservoirs, threatening drinking water safety. However, the variations in DOM and DBP precursors in deep-water reservoirs during algal bloom remain unclear. UV and fluorescence spectroscopy and chlorination experiments were used to analyze the variations in DOM and DBP precursors during algal bloom in the Sanhekou Reservoir. Before algal bloom, the DOM and DBP precursors decreased due to biodegradation. After algal bloom, the DOM and DBP precursors increased by 48.3% and 86.9% due to algae producing protein-like compounds. Notably, the algal bloom produced a range of nitrogenous compounds that significantly promote the formation of trichloronitromethane, a major contributor to the mammalian cytotoxicity associated with DBPs. In addition, the heterogeneous matrix led to the stratification of DOM and DBP precursors. The surface water (0–5 m) was more vulnerable to algae, with protein-like components being much higher than in other layers, while humic and fulvic-like components were much lower. However, high temperatures and sufficient oxygen conditions accelerated the biodegradation of DOM and DBP precursors, resulting in significantly lower levels of DOM and DBP precursors in the surface water compared to other layers (p < 0.05). This study provides insights into the variations and the drivers in DOM and DBP precursors during algal bloom, essential for developing water intake strategies in similar water reservoirs. [Display omitted] • Algae blooms greatly increased DOM and DBP precursors. • Algae and heterogeneous matrix led to DOM and DBPs stratification. • Algae, temperature, and DO were major drivers in DOM and DBP precursors. • The relationship between DOM properties and DBPs was changed after algae blooms. [ABSTRACT FROM AUTHOR]

• Iron particles significantly enhance DBPs formation during HA chlorination. • PFRs accumulation on iron particles boosts ·OH generation and HA decomposition. • Preformed iron particles, accumulating oxygen-centered PFRs, yield more DBPs. • More unknown N-DBPs and Cl-DBPs were formed with iron particles present. • PFR activation by iron particles is a noteworthy DBP formation risk in DWDS. The widespread presence of iron (Fe) particles and natural organic matter (NOM) in drinking water distribution systems (DWDS) can significantly affect tap water quality, contributing to aesthetic issues and potentially generating harmful disinfection byproducts (DBPs). This study revealed that Fe particles, when combined with humic acid (HA), substantially increased DBP formation during chlorination. Fe particles (particularly preformed Fe particles) significantly increased haloacetic acid (HAA) formation by activating the persistent free radicals (PFRs) in the HA. Compared with the control system without Fe particles, greater than 2 times of HAA increase were observed for the system with Fe pariticles. PFRs accumulated on Fe particle surface could generate hydroxyl radicals, facilitating the decomposition of HA into smaller molecules, which were more reactive with chlorine disinfectants, thus elevated the DBP formation including both known and unknown N-DBPs and Cl-DBPs. The DBP promotion effect of in-situ formed Fe particles was much less than that of preformed Fe particles although both in-situ formed and preformed Fe particles could accumulate PFRs from HA. In-situ formed particles primarily accumulated carbon-centered PFRs, while preformed particles accumulated oxygen-centered PFRs. To mitigate the Fe particle induced water quality risks, it is crucial to control iron pipe corrosion and iron release in DWDS. In addtion, the optimization of treatment processes such as coagulation and filtration to more completely remove NOM and Fe particles could help minimize the DBP formation. [Display omitted] [ABSTRACT FROM AUTHOR]

• Total concentration of volatile DBPs in drinking water of suzhou was 64.6–83.0 µg/L. • During LLE - N2 blow-down, most of volatile DBPs and TOX (>60 %) have been lost. • Volatile DBPs are key contributor to TOX in tap water and LLE - N2 blow-down samples. • LLE - solvent exchange is a good substitute of XAD and SPE methods for bioanalysis. Liquid-liquid extraction (LLE) combined with the N 2 blow-down method is a promising tool for bioanalysis of drinking water. However, detailed information on which disinfection byproduct (DBP) classes are retained in LLE extracts is currently unavailable. In this study, the recovery of seven classes of volatile DBPs and total adsorbable organic halogens (TOX) during the LLE method, combined with three common N 2 blow-down methods, for bioanalysis in real tap water was analyzed at a 2-L scale, along with their corresponding cytotoxicity. The total concentration of seven classes of volatile DBPs in drinking water in Suzhou ranged from 64.6 to 83.0 µg/L, with the majority contributed by trihalomethanes (THMs: 59.9 µg/L), haloaldehydes (HALs: 5.4 µg/L), haloacetamides (HAMs: 3.4 µg/L), and haloacetonitriles (HANs: 3.2 µg/L). During the LLE - N 2 blow-down process for bioanalysis, about 69–85 % of targeted volatile DBPs and 64–75 % of TOX were lost, respectively. Seven classes of volatile DBPs accounted for 52.8–64.3 % and 23.8–61.3 % of TOX in tap water and LLE - N 2 blow-down samples, respectively, suggesting that targeted aliphatic DBPs are the key contributors to TOX. Furthermore, although LLE - solvent exchange had a better recovery performance than other N 2 blow-down methods, the recoveries of volatile DBPs using this method were still not ideal. For example, HALs and HAMs had a slightly better recovery (>50 %), while most volatile DBPs had a poor recovery, including iodo-trihalomethanes (I-THMs, 0 %), haloketones (28 %), THMs (26 %), halonitromethanes (33 %), and HANs (38 %). During LLE - solvent exchange, 31 % and 36 % of targeted DBPs and TOX, respectively, in real tap water can be retained, which shows better performance than non-ionic macroporous copolymers (XAD). More importantly, the water volume required in this method for cytotoxicity analysis is 2 L, which greatly reduces the burden of water sample collection, transport, and pre-treatment compared to XAD (which typically requires 5 or 10 L). In general, this paper reveals the fate of volatile DBPs during LLE - N 2 blow-down and indicates that LLE - solvent exchange is a good substitute for the XAD method in bioanalysis. [Display omitted] [ABSTRACT FROM AUTHOR]

• Identified about 100 unreported N-DBPs during chloramination of phenolic compounds. • Revealed structural diversity of the novel N-DBPs using HRMS and DFT calculations. • Proposed novel formation pathways of N-DBPs through experiments and computations. • Explored the unreported bonding mechanisms of coupling heterocyclic N-DBPs. Disinfection is critical for ensuring water safety; however, the potential risks posed by disinfection byproducts (DBPs) have raised public concern. Previous studies have largely focused on low-molecular-weight DBPs with one or two carbon atoms, leaving the formation of high-molecular-weight DBPs (HMW DBPs, with more than two carbon atoms) less understood. This study explores the formation of HMW DBPs during the chloramination of phenolic compounds using a novel approach that combines high-resolution mass spectrometry with density functional theory (DFT) calculations. For the first time, we identified nearly 100 previously unreported HMW nitrogenous DBPs (N-DBPs), with nearly half of those being halogenated N-DBPs. These N-DBPs were tentatively identified as heterocyclic (e.g., pyrrole and pyridine analogs) and coupling heterocyclic N-DBPs. Through detailed structure analysis and DFT calculations, the key formation steps of heterocyclic N-DBPs (monochloramine-mediated ring-opening reactions of halobenzoquinones) and new bonding mechanisms (C–N, C–O, and C–C bonding) of the coupling heterocyclic N-DBPs were elucidated. The selective formation of these novel N-DBPs was significantly influenced by factors such as contact time, monochloramine dosage, pH, and bromide concentration. Our findings emphasize the occurrence of diverse HMW heterocyclic N-DBPs, which are likely toxicologically significant, underscoring the need for further research to evaluate and mitigate their potential health risks in water disinfection. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Colorimetric method capable of quantifying trihalomethanes in drinking water. • A method that can be adapted for minimally equipped laboratories. • The method was validated according to validation protocols. • The detection and quantification limits were 13.41 and 40.65 μg L−1, respectively. • Recovery assays ranged from 86.1 to 90.7 % and precision was <14 %. Chlorine is a common disinfectant used in water treatment. However, its reaction with organic matter can lead to the formation of harmful byproducts, such as trihalomethanes (THMs), which are potentially carcinogenic. To address this issue, the aim of this work was to enhance a colorimetric method capable of quantifying THMs in drinking water through UV/Vis Spectrophotometry, using cost-effective equipment, and validate this methodology for the first time according to established validation protocols. The method's innovation involved replacing the solvent pentane with the more common hexane, along with adjusting the heating ramp, elucidating the mechanisms involved in the process. This method involves the reaction between THMs, pyridine, and NaOH to produce a colored compound, which is then monitored through molecular absorption spectroscopy in the visible region. The method was thoroughly validated, achieving a limit of detection of 13.41 μg L−1 and a limit of quantification of 40.65 μg L−1. Recovery assays ranged from 86.1 % to 90.7 %, demonstrating high accuracy. The quality of the linear fit for the analytical curve exceeded R2 > 0.98. The method was applied to real samples, revealing concentrations ranging from 13.58 to 55.46 μg L−1, all way below the legal limit in Brazil (Maximum Contaminant Levels (MCL) = 100 μg L−1). This cost-effective and straightforward method is suitable for integration into water treatment plant laboratories. [ABSTRACT FROM AUTHOR]