Water Research最新文献

{"title":"Reduced Cytochrome c: Exploring Its Promoting Function in Synergistic Denitrification by Pseudomonas sp. JM-7 and Thiobacillus denitrificans","authors":"Bobo Xing ,&nbsp;Ji Li ,&nbsp;Linlin Li ,&nbsp;Nigel J.D. Graham ,&nbsp;Xian Li ,&nbsp;Wenzheng Yu","doi":"10.1016/j.watres.2025.124109","DOIUrl":"10.1016/j.watres.2025.124109","url":null,"abstract":"<div><div>Excessive accumulation of nitrate in natural ecosystems can lead to eutrophication of water bodies, resulting in environmental impacts such as algal blooms and red tides that pose serious threats to environmental and human health. Autotrophic denitrification is a resource-efficient biological nitrogen removal technology, but the slow growth and low electron transfer efficiency of autotrophic denitrifiers limit their practical application. In this study, the heterotrophic denitrifying bacterium <em>Pseudomonas</em> sp. JM-7 (<em>P.</em> JM-7) was used in mixed culture with the autotrophic denitrifying <em>Thiobacillus denitrificans</em> ATCC 25259 to form a heterotrophic-autotrophic synergistic denitrification process (mixPT) to enhance electron transfer and improve the denitrification efficiency. Our results for an initial nitrate concentration of 430 mg/L showed that <em>P.</em> JM-7 reduced approximately 210 mg/L nitrate (48.8 %) in 90 h, with 1 g/L yeast extract powder (YEP) as the electron donor, while <em>Thiobacillus denitrificans</em> barely removed nitrate. In contrast, the mixPT system reduced approximately 360 mg/L nitrate (83.3 %), nearly 1.7 times greater than <em>P.</em> JM-7 alone. The mixPT culture also exhibited excellent denitrification in low carbon waters (10 mg/L), and removed 40 mg/L nitrate completely within 120 h. Cytochrome c produced by <em>Pseudomonas</em> sp. JM-7, which is an excellent electron transfer mediator for denitrification by <em>Thiobacillus denitrificans</em>, played a crucial role in the heterotrophic-autotrophic syntrophic denitrification. The adsorption effect of <em>Pseudomonas</em> sp. JM-7 shortened the contact distance between the autotrophic denitrifying bacteria and cytochrome c, which made it easy for cytochrome c to transfer the electrons to the autotrophic bacteria directly, thereby reducing the loss of electrons in the process of transfer, and improved the electron utilization efficiency. These findings have demonstrated the potential applications of mixPT system in controlling eutrophic waters and propose cytochrome c of <em>Pseudomonas</em> sp. JM-7 could serve as a novel and high-quality electron transfer mediator. Furthermore, this study have overcome the restriction of low denitrification efficiency exhibited by heterotrophic denitrifying bacteria <em>Pseudomonas</em> sp. JM-7 in low-carbon environments and expanded the utilisation of <em>Pseudomonas</em> sp. JM-7 in low carbon environments.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"285 ","pages":"Article 124109"},"PeriodicalIF":11.4,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144515369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Critical Raw Materials in River Waters: First Observation of Lutetium Microcontamination of the Isère and Rhône Rivers, Southern France","authors":"Addis Kokeb Alemu, Keran Zhang, Lukas Klose, Dennis Kraemer, Michael Bau","doi":"10.1016/j.watres.2025.124105","DOIUrl":"https://doi.org/10.1016/j.watres.2025.124105","url":null,"abstract":"The increasing use of rare earth elements and yttrium (REY) in enabling technologies is accompanied by their increasing release into the environment as emerging (micro-)contaminants. Starting with the detection of anthropogenic gadolinium (Gd) contamination in German rivers in 1996, currently available data on the distribution of REY in surface waters worldwide shows anthropogenic positive Gd anomalies derived from Gd-based contrast agents used in magnetic resonance imaging, and at few locations positive La and Sm anomalies. However, in addition to the omnipresent positive Gd anomalies, the Isère River downstream of the city of Grenoble in southern France shows large positive lutetium (Lu) anomalies. These data which are confirmed by different analytical approaches in two different laboratories, are the first report ever of large positive Lu anomalies observed in surface waters. The very large size of the positive Lu anomaly most strongly suggests that this represents an anthropogenic Lu (micro-)contamination of the river. The origin of the anomalously high Lu concentrations can be tracked to the effluents from the wastewater treatment plant (WWTP) Aquapole in the city of Grenoble. This Lu is then diluted and hence decreases in concentration further downstream, but the anthropogenic Lu anomaly is still visible in REY data for the Rhône River. Repeated sampling over 15 months strongly suggests that the Lu (micro-)contamination of the Isère and Rhône rivers from the WWTP Aquapole is persistent and not a transient phenomenon related to a one-time event. The anthropogenic Lu shows natural isotope abundances and does not reflect pollution with radionuclides. The addition of Lu to the set of critical metals present as microcontaminants of the hydrosphere clearly reveals the necessity of better monitoring the distribution of REY and other formerly “exotic” elements and their release into the environment.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"58 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144488782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mitigation of opportunistic drinking water pathogens by onsite monochloramine disinfection in a hospital water system","authors":"Marianne Grimard-Conea ,&nbsp;Xavier Marchand-Senécal ,&nbsp;Sébastien P. Faucher ,&nbsp;Michèle Prévost","doi":"10.1016/j.watres.2025.124107","DOIUrl":"10.1016/j.watres.2025.124107","url":null,"abstract":"<div><div>In acute care hospitals, susceptible patients and large, legacy water systems contribute to increased risk of nosocomial infections associated with drinking water pathogens. This study aimed to evaluate the long-term (&gt;1-year) impact of onsite monochloramine treatment on <em>Legionella pneumophila</em> (<em>Lp</em>), nontuberculous mycobacteria (NTMs), <em>Vermamoeba vermiformis</em> (<em>Vv</em>), and physico-chemical water quality in a hospital hot water system. Using an innovative sampling approach, the efficacy of treatment was assessed at 22 distal sites (faucets, showerheads, handwashing stations) and compared to 10 control points representing the main flowing distribution system (return loops, heaters, remote sites). Monochloramine nearly eliminated <em>Lp</em>, achieving up to 3-log reductions in culturability (&lt;24 h) and gene copies (4-week). Mean <em>Vv</em> concentrations decreased by 2-log within 24 h, with no evidence of a shift towards increased NTMs. Optimal reductions in all organisms were observed at monochloramine concentrations of 2–3 mg/L combined with temperatures exceeding 55 °C. However, these conditions were only consistently maintained at control points, where post-treatment mean concentrations were systematically 1-log lower than those at distal sites. The interruption of dosage (5-day and 4-week) also revealed significant and rapid rebounds of <em>Legionella</em>, NTMs, and <em>Vv</em> (&gt;1–2-log), highlighting their persistence in biofilms. Short-term increases in metal release were observed, with mean copper and lead concentrations rising 1.8- and 4.6-fold, respectively. Overall, results confirmed the high and rapid efficacy of onsite monochloramine to control <em>Lp</em> and other organisms. Analysis of water quality, temperature distribution, and usage patterns emphasize the importance of maintaining optimized hydraulic and thermal regimes to ensure effective pathogen control at points of exposure. This study provides actionable insights and practical evidence to support healthcare facilities in implementing robust long-term monitoring and control strategies.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"285 ","pages":"Article 124107"},"PeriodicalIF":11.4,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144479603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Removal of organic micropollutants under dry and wet weather conditions in a full-scale aerobic granular sludge plant","authors":"Zhaolu Feng ,&nbsp;Heike Schmitt ,&nbsp;Mark C M van Loosdrecht ,&nbsp;Nora B Sutton","doi":"10.1016/j.watres.2025.124108","DOIUrl":"10.1016/j.watres.2025.124108","url":null,"abstract":"<div><div>Aerobic granular sludge (AGS) process is an effective wastewater treatment technology for nutrient and organic matter removal and is being widely applied worldwide. To date, its performance in removing organic micropollutants (OMPs), particularly under wet weather conditions when operation differs, remains poorly understood. This study evaluated the occurrence and removal of OMPs, including 19 pharmaceuticals and 2 industrial compounds, in a full-scale AGS plant during one year under both dry and wet weather conditions. Under dry weather conditions, influent concentrations of 5 pharmaceuticals and 1 industrial compound exceeded 1 μg L⁻¹. Rainfall resulted in diluted OMP influent concentrations, but also caused a significant increase in the influent load of 6 OMPs with positively charged functional groups, likely due to mobilization of sewage sediments that had adsorbed these OMPs. Under dry weather conditions, average removal efficiencies of 14 compounds were greater than 20 %, with 6 of these compounds detected in the sludge phase, and thus likely removed through sorption. Under wet weather conditions, OMP removal efficiencies decreased by 8 % to 38 %. Shortened aeration reaction time significantly reduced (<em>p</em>-value&lt;0.05; R²&gt;0.5) the removal of 8 potentially biodegradable compounds, while the impact on sorption-driven removal was limited for 6 compounds. Effluent OMP load increased under wet weather conditions, mainly due to reduced removal efficiency, rather than the discharge of OMPs adsorbed onto suspended solids. Under dry weather conditions, the AGS plant exhibited comparable or slightly higher OMP removal efficiencyies than activated sludge plants; however, differences in performance under wet weather conditions remain unclear due to limited data on activated sludge systems. Overall, this study is the first to assess OMP removal in a full-scale AGS plant under wet weather, showing the impact of increased flow on the sorption and biotransformation of OMPs.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"285 ","pages":"Article 124108"},"PeriodicalIF":11.4,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144488483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydraulic efficiency and mixing dynamics in surface flow constructed wetlands: Influence of design, vegetation phenology, and climate variability","authors":"Charlotte Dykes ,&nbsp;Jonathan Pearson ,&nbsp;Gary D. Bending ,&nbsp;Soroush Abolfathi","doi":"10.1016/j.watres.2025.124110","DOIUrl":"10.1016/j.watres.2025.124110","url":null,"abstract":"<div><div>Surface flow constructed wetlands (CWs) are a nature-based wastewater treatment technology designed to serve as a buffer between wastewater treatment plants (WWTPs) and the receiving environment. While the treatment efficacy of CWs has been investigated, surface flow systems are susceptible to hydraulic inefficiencies, and a comprehensive understanding of the factors influencing pollutant transport remains limited, hindering their optimisation and predictability. The hydraulic performance of a CW, determined by the efficiency of flow hydrodynamics, dictates the residence time and spatial interactions between pollutant-laden water and purification mechanisms, such as those provided by vegetation and substrate. However, unstandardised designs and a limited understanding of water-sediment-plant interactions often result in sub-optimal hydraulic conditions, such as short-circuiting and dead zones, which impair treatment efficiency. This study investigates the influence of inter-seasonal climate variability, vegetation growth cycles, and operational conditions on the interplay between hydraulic performance, and subsequent pollution removal efficacy, in a full-scale integrated surface flow CW located in Norfolk, UK. Five tracer test campaigns were conducted during 2022–2023 using Rhodamine WT dye and fluorometric sensors to evaluate seasonal variations in hydraulic behaviour across four interconnected vegetated Cells. Hydraulic performance was characterised using indices such as mean residence time, tank-in-series model, hydraulic efficiency, effective volume ratio, short-circuiting, mixing, and dispersion coefficients. To understand the roles of CW design, operation, vegetation, and climate on hydraulic performance, high-resolution LiDAR vegetation scans, nutrient concentrations, and climate monitoring data were collected concurrently with the tracer tests. The combined mean residence time ranged from 30.03 h in autumn to 47.67 h in summer. Individual Cell hydraulic indexes revealed significant non-uniform flow patterns, with 80 % of tracer tests indicating poor (<span><math><mi>λ</mi></math></span> &lt; 0.5) hydraulic efficiency and 55 % exhibiting dead zones occupying &gt;50 % of the Cell volume. These inefficiencies were predominantly driven by smaller Cell geometries, sub-optimal inlet-outlet configurations, high influent hydraulic loading rates (0.47 to 0.66 m³/day/m²), and high emergent vegetation cover. Despite these hydraulic deviations, Cell nutrient removal performance was more strongly influenced by vegetation growth stage and seasonal water physicochemical conditions. These findings provide novel field-scale data into how design, seasonal, and operational factors influence CW performance, highlighting the critical need for enhanced design and management strategies to optimise hydraulic and treatment performance in CWs, particularly in climate variability.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"285 ","pages":"Article 124110"},"PeriodicalIF":11.4,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144488832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cooperating oxidative half-reaction deactivate electrocatalyst for nitrate reduction in real wastewater","authors":"Chunxia Zhang ,&nbsp;Zhuanzhuan Li ,&nbsp;Kemeng Zhang ,&nbsp;Yunpu Zhai ,&nbsp;Changsen Zhang ,&nbsp;Panpan Liu","doi":"10.1016/j.watres.2025.124097","DOIUrl":"10.1016/j.watres.2025.124097","url":null,"abstract":"<div><div>Electrocatalytic nitrate reduction to ammonia (eNO₃RA) paves a promising way toward nitrate mitigation and ammonia recovery from real wastewater. While the complex constituents in real wastewater raise concerns about the stability of catalysts. Here, the comprehensive investigation of the stability of easy-to-prepare Cu_xO nanowires for eNO₃RA is performed in real wastewater. Irreversible catalyst deactivation is observed in short-term operation for eNO₃RA and ammonia selectivity decreases from 82.02 to 28.37 % due to the ineffective hydrogenation of intermediates. Conversely, the performance decrease for long-term eNO₃RA in confined electrolytes can be recovered with oven drying of the catalyst. The irreversible deactivation of the catalyst proceeds with the aggregation of nanowires as the oxidation of Cu⁺ to Cu²⁺. Chloride ion is recognized as the main contributor due to the cooperating oxidative half-reaction at the anode. These findings emphasize the need for careful consideration of the catalysts’ stability in the design of electrochemical systems for eNO₃RA.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"285 ","pages":"Article 124097"},"PeriodicalIF":11.4,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144371059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Responses of viral communities in aerobic biofilms under antibiotic stress","authors":"Chen Wang ,&nbsp;Xiao Luan ,&nbsp;Junya Zhang ,&nbsp;Hong Zhang ,&nbsp;Yu Zhang ,&nbsp;Min Yang ,&nbsp;Zhe Tian","doi":"10.1016/j.watres.2025.124099","DOIUrl":"10.1016/j.watres.2025.124099","url":null,"abstract":"<div><div>Bacteriophages are pivotal in shaping microbial communities, but their structural and functional responses to antibiotic stress in aerobic biofilms remain underexplored. This study aims to fill this void by providing a comprehensive understanding of how viral communities in aerobic biofilms adapt to increasing antibiotic pressures through interactions with their bacterial hosts. Three lab-scale aerobic biofilm systems were established and operated for 577 days, two of those were exposed to increasing influent concentrations of oxytetracycline (OTC) and streptomycin (STM), respectively. The dynamics of the biofilm virome under antibiotic stress was revealed by metagenomic sequencing. Results showed that the virome in aerobic biofilms displayed a high percentage (98.7 %) of unknown bacteriophages, indicating considerable viral diversity. As for the hosts of phages, a total of 1741 bacteriophage contigs were associated with 660 distinct bacterial hosts. In antibiotic-treated systems, broad-host-range generalist bacteriophages accounted for over 17.95 % (STM) and 17.90 % (OTC), compared to 14.32 % in the control. Furthermore, viral community did not carry diverse antibiotic resistance genes, which only accounted for 0.34 % of the resistome. Additionally, it did not regulate the number of resistant bacteria by activating the lytic and lysogenic cycles in this study. This indicated that the contribution of transduction to the horizontal spread of resistant determinants is very limited in the aerobic biofilm. Under antibiotic stress, viral auxiliary metabolic genes compensated for incomplete metabolic pathways in host cells, particularly those related to carbohydrate, amino acid, and cofactor metabolism. These genes likely offer dual benefits to bacterial hosts by repairing antibiotic-induced cellular damage and supporting energy generation, thereby providing adaptive advantages for bacterial survival and proliferation under antibiotic selection pressure. This study uncovers the complex interactions between bacteriophages, their hosts, and environmental pressures. It suggests that viral communities in these environments compensate for functional metabolism rather than promote resistance development under antibiotic stress, providing new insights into the potential roles of bacteriophages in the regulation of microbial-driven processes.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"285 ","pages":"Article 124099"},"PeriodicalIF":11.4,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144479602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combined effects of polystyrene nanoplastics and dinophysistoxin-1 (DTX1) on physiological performance of marine diatom Thalassiosira minima","authors":"Natnael Sisay Demo ,&nbsp;Jiangbing Qiu ,&nbsp;Guowang Yan ,&nbsp;Ruolin Wu ,&nbsp;Mohammad Sadiq Nikzad ,&nbsp;Aifeng Li","doi":"10.1016/j.watres.2025.124104","DOIUrl":"10.1016/j.watres.2025.124104","url":null,"abstract":"<div><div>Currently micro- and nanoplastics (MNPs) and microalgal toxins have become two typical groups of emerging contaminants in various coastal regions worldwide. However, the knowledge about their combined effects on marine organisms is still limited. This study explored the single and combined effects of polystyrene nanoplastics (PSNPs) at 50 mg L^–1 and dinophysistoxin-1 (DTX1) at 1 µmol L^–1 (819 μg l^-1) on the diatom <em>Thalassiosira minima</em>. Results showed that the growth of <em>T. minima</em> was reduced by 22 ± 1.6 %, 53 ± 2.7 %, and 40 ± 2.8 % in DTX1, PSNPs, and their combined treatments, respectively. The maximum adsorption potential of DTX1 on PSNPs reached 78 % after 24 h, which might explain the antagonistic effect of PSNPs and DTX1 on growth and oxidative stress parameters. However, they demonstrated an additive effect on chlorophyll <em>a</em> biosynthesis, nitrogen assimilation, and the silicification of diatoms. The coupling of the silica to nitrogen (Si:N) uptake ratio in diatoms was significantly altered; extracellular dissolved inorganic nitrogen (DIN) in the treatment of PSNPs was reduced by 11.3 ± 4.1 %, while it increased by 47.9 ± 14 % and 60.4 ± 6.9 % in treatments with DTX1 and the combined treatment, respectively. Silicification of <em>T. minima</em> was reduced by 50 ± 5.9 % and 49 ± 1.8 % in treatments with DTX1 alone and the combined treatment, respectively. These findings suggest that DTX1 exposure results in an increase in N uptake and a decrease in Si uptake, demonstrating an inverse effect on the uptake of nutrients. Transcriptome analysis revealed downregulation of some amino acid genes possibly accounts for this change. This study is significant for understanding the combined effects of microplastics and phycotoxins on diatoms.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"285 ","pages":"Article 124104"},"PeriodicalIF":11.4,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144479607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative probe detection of photosensitized dibromide radical anions generated from dissolved organic matter in aquatic systems","authors":"Fangyuan Cheng ,&nbsp;Tingting Zhang ,&nbsp;Hao Yang ,&nbsp;Jiao Qu ,&nbsp;Weihua Song ,&nbsp;Ya-nan Zhang","doi":"10.1016/j.watres.2025.124102","DOIUrl":"10.1016/j.watres.2025.124102","url":null,"abstract":"<div><div>Dibromide radical anions (Br₂^•−) are prevalent in marine and estuarine waters, significantly influencing the photochemical transformation of pollutants. Despite their importance, the lack of probes to quantitatively detect Br₂^•− greatly hampers the understanding of their environmental behavior. In this study, we demonstrated that 3,5-dimethyl-1-H-pyrazole (DMPZ) can detect Br₂^•− in aqueous solutions containing dissolved organic matter (DOM) and halide ions under simulated sunlight irradiation. The formation of Br-DMPZ through the reaction of DMPZ with Br₂^•− serves as a reliable indicator of Br₂^•− presence. The secondary reaction rate constant of DMPZ with Br₂^•− was determined to be 1.68 × 10⁷ M⁻¹ s⁻¹. The steady-state concentration of Br₂^•− ([Br₂^•−]ss) produced by DOM in water with seawater-level concentrations of halides (540 mM Cl⁻ + 0.8 mM Br⁻) under simulated sunlight irradiation was determined to be at the level of 10⁻¹⁸ M using DMPZ as a probe. Meanwhile, the [Br₂^•−]ss in natural seawater was measured to be at the level of 10⁻²⁰ M. Furthermore, preliminary exploration of Br₂^•− generation using DOM model compounds suggested that aromatic ketones and electron-rich chromophores may contribute to Br₂^•− formation. These findings confirm the feasibility of using DMPZ as a quantitative probe for Br₂^•− in seawater under light conditions, thereby enhancing our understanding of bromine radical formation in water and the complex environmental processes involved.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"285 ","pages":"Article 124102"},"PeriodicalIF":11.4,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144479606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting suspended floc size in estuarine waters using self-adaptive parameterized physics-informed neural networks","authors":"Ya Wu,&nbsp;Leiping Ye,&nbsp;Jie Ren,&nbsp;Jiaxue Wu","doi":"10.1016/j.watres.2025.124094","DOIUrl":"10.1016/j.watres.2025.124094","url":null,"abstract":"<div><div>The size dynamics of suspended flocs play fundamental roles in sediment transport processes and ecological functioning in estuarine waters. However, conventional flocculation dynamic models typically rely on fixed empirical parameters, limiting their adaptability under complex hydrodynamic conditions and reducing predictive accuracy. This study presents a new self-adaptive parameterized physics-informed neural networks (SAP-PINNs) model, dynamically optimizing aggregation coefficient, breakage coefficient and erosion parameters within the flocculation dynamic equation, enhancing the accuracy and physical consistency of floc size predictions by integrating data-driven methodologies with physical constraints. Laboratory experiments demonstrate that the model, calibrated under low shear stress conditions, accurately predicts mean floc size under high shear stress, confirming its robustness across variable hydrodynamic regimes. Field validations further indicate a significant improvement in predictive performance compared to traditional models, with an 88.31 % increase in accuracy, a coefficient of determination of 0.99, and a mean absolute error of 0.78. SHapley Additive exPlanations (SHAP) analysis reveals that shear stress and salinity are the dominant factors influencing flocculation, while suspended sediment concentration exhibits a facilitative effect within an optimal range. Temperature exerts a comparatively minor influence. This study demonstrates that the SAP-PINNs effectively combines physical laws with machine learning techniques, improving the modeling accuracy, interpretability, and generalizability of floc dynamics. It offers a new promising potential for application in complex hydrodynamic systems, supporting sediment transport predictions, ecological assessments, and water quality management in estuarine and coastal waters.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"285 ","pages":"Article 124094"},"PeriodicalIF":11.4,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144371061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}