The molecular compositions of organic components in winter PM_2.5 samples from a typical urban area of Chongqing were analyzed by electrospray ionization coupled with ion mobility spectrometry-time of flight mass spectrometry (ESI-IMS-TOF-MS). Sulfur-containing organics (CHOS+CHNOS) were important components in organic aerosol, and their relative abundance accounted for more than 70% on average. IMS-derived collision cross section, collision-induced dissociation, and Kendrick mass defect analyses verified the presence of organosulfates (OSs). Molecular characterization results indicated that sulfur-containing organics were dominated by carbohydrate and lignin species and had higher oxidation degree in Chongqing urban area compared with other cities. Biogenic and anthropogenic precursors were important sources of sulfur-containing organics. The relationships between aerosol liquid water content, acidity and inorganic sulfate with sulfur-containing organics suggested that aqueous-phase chemistry and acid-catalyzed chemistry play important roles in the formation of sulfur-containing organics.

Oxidative potential (OP) is a crucial indicator for evaluating the capacity of PM_2.5 to trigger oxidative stress. Therefore, this study employed dithiothreitol (DTT) method to measure the OP of PM_2.5. During the observation period, the results indicated that the daily average concentration of atmospheric PM_2.5 in Taiyuan severely exceeded the standard, with a maximum concentration reaching 150.91µg/m³, signifying severe air pollution. The daily average values for volume-normalized (DTT_v) and mass-normalized (DTT_m) DTT activity were (2.90±1.07)nmol/(min·m³) and (38.34±18.91)pmol/(min·µg), respectively. Meanwhile, a significant positive correlation was observed between PM_2.5 mass concentration and DTT_v (r=0.916, P<0.01), while a negative correlation was found with DTT_m. Furthermore, DTT_v exhibited significant correlations (P<0.05) with organic carbon (OC), elemental carbon (EC), metallic elements (Fe, Mn, Zn, Pb), and ionic components (K⁺, Cl^-, etc.) within PM_2.5. These phenomena suggested that DTT activity primarily depends on specific components of PM_2.5. The study further integrated the positive matrix factorization (PMF) model with the multiple linear regression algorithm. Quantitative analysis revealed that solid fuel combustion sources, such as coal combustion, were the most important sources of OP in Taiyuan, contributing 54.7%, followed by motor vehicle sources (23.3%) and dust sources (22.0%).

Per-/polyfluoroalkyl substances (PFASs) and pharmaceuticals and personal care products (PPCPs) were selected as the typical emerging contaminations to investigate the pollution characteristics in the atmospheric particulate matter (APM) of Chengdu. Concentration levels of 25PFASs and 9PPCPs in the APM of Chengdu were analyzed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and source analysis was carried out on the PFASs, and the concentrations of the PFASs were correlated with total suspended particulate matter(TSP). The results showed that 10PFASs and 1PPCPs were detected in the APM. ∑₁₀PFASs concentrations ranged from 4.58 to 647.59pg/m³, with a mean value of 140.81pg/m³, and the highest level was found in PFBA (mean value of 133.18pg/m³). The concentration of ∑PPCPs ranged from 34.98 to 474.00pg/m³, with a mean value of 189.88pg/m³, among which cotinine (CTN) was the only detected PPCP. The principal component analysis indicated that the atmospheric PFASs in the atmosphere of Chengdu were mainly originated from the surfactants, textile and leather industries. Except for 6:2 Fluorotonous Sulfonic Acid (6:2FTSA) and perfluorobutanoic acid (PFBA), all the other PFASs showed a significant positive correlation with TSP(P<0.05), which is related to the presence of Fe₂O₃ oxides and organic matter in atmospheric particulate matter discussed.

This study takes the Wujing Road Tunnel in Tianjin as an example to explore the emission characteristics of benzothiazoles (BTs) in particulate, gaseous pollutants, and road dust. The results show that the concentrations of particulate matter, gaseous pollutants, and BTs in road dust exhibit regular patterns, especially the concentration changes of 2-hydroxybenzothiazole (2-OH-BT) and benzothiazole (BT). Since BTs in the enclosed tunnel environment mainly originate from tire wear particles of motor vehicles, 2-OH-BT and BT can serve as important tracers for identifying non-exhaust emissions from motor vehicles. During the tunnel experiment, the daily traffic volume ranged from 11,972 to 16, 157 vehicles per day, the total carbon (TC) concentration was between 10.85and 15.75μg/m³, and the BTs concentration was between 3.33 and 8.41ng/m³. The gas-particle ratio values of 2-mercaptobenzothiazole (MBT), 2-OH-BT, and BT in the tunnel were generally higher than those in the receptor environment, and 2-OH-BT and BT were the dominant gaseous BTs components. This indicates that most MBT, 2-OH-BT, and BT generated from tire wear sources of motor vehicles are released in the gaseous phase, so the gaseous BTs should not be overlooked. For the calculation of motor vehicle emission factors, the average emission factors of organic carbon (OC), elemental carbon (EC), and PM_2.5 in the Wujing Road Tunnel were 2.80, 1.60, and 13.77mg/(km⋅vehicle), respectively. In the health risk assessment model, the daily exposure to BTs through ingestion was the highest. The daily intake for children and adults was 12.03 and 1.29ng/(kg⋅d), respectively. The total daily exposure for children was more than nine times that of adults, indicating that children may face a greater health threat from traffic pollution than adults.

Cooperative strategies that mitigate competition among dominant functional microorganisms are crucial for efficient nitrogen and phosphorus removal in wastewater treatment. This study investigated a novel single-stage sequencing batch reactor operating under an anaerobic/anaerobic/oxic/anaerobic (A/A₁/O/A₂) mode for 100days to regulate the dynamic balance of phosphorus-accumulating organisms (PAOs), denitrifying PAOs (DPAOs), and denitrifying glycogen-accumulating organisms (DGAOs). The optimized system, featuring a recycle loop and reduced aerobic phase duration, achieved nitrogen and phosphorus removal efficiencies of (95.13%±0.35%) and (94.70%±0.96%), respectively. Mechanistic analysis suggested that the A₁ phase created an anoxic environment conducive to DPAO-mediated denitrifying phosphorus removal, while the A₂ phase supported DGAO-driven denitrifying nitrogen removal using polyhydroxyalkanoates (PHAs) and glycogen (Gly). Extracellular polymeric substance (EPS) analysis revealed increases of 35.38mg/gVSS in protein (PN) and 12.39mg/gVSS in polysaccharide (PS) content, enhancing sludge aggregation. Microbial community analysis demonstrated significant enrichment of Dechloromonas and Ca. Competibacter, with their abundances increasing from 2.24% and 1.53% in R1to 7.61% and 7.94% in R2, respectively. The A/A₁/O/A₂ mode effectively created a synergistic environment for key DPAOs and DGAOs, achieving superior nitrogen and phosphorus removal performance compared to conventional modes.

This study aimed to investigate the influencing mechanism of polystyrene nanoplastics (PS-NPs) in aerobic granular sludge (AGS) systems. The addition of 20mg/L PS-NPs had a negligible impact on the removal of organic matter and phosphorus in the AGS systems. However, it exerted a pronounced inhibitory effect on nitrogen removal, with ammonia nitrogen removal and total nitrogen removal exhibiting a reduction of 21.98% and 41.31% compared to the control group, respectively. Additionally, PS-NPs inhibited the secretion of extracellular polymeric substance (EPS) and altered the EPS structure, making it looser by affecting the secondary structure of proteins. Further studies demonstrated that PS-NPs caused intense oxidative stress within microorganisms by inducing excessive reactive oxygen species (ROS) production, which resulted in lactic dehydrogenase (LDH) levels rising to 151.27% and compromised cell membrane integrity. The long-term presence of PS-NPs led to changes in microbial community structure, inhibiting the growth of denitrifying bacteria, such as the classes Gammaproteobacteria and Alphaproteobacteria. In contrast, the proliferation of the classes Flavobacteria and Chitinophagia was promoted by PS-NPs. Moreover, KEGG database analysis indicated that PS-NPs not only significantly inhibited the pathways related to quorum sensing and metabolic activity, particularly the metabolic pathways of aromatic amino acids, but also reduced the relative abundance of genes encoding denitrifying functional enzymes. This ultimately posed a negative impact on the denitrification performance and the long-term stability of AGS systems.

This study evaluated the short-term, acute impacts of elevated Cu(II) and Cr(VI) concentrations on the nitrogen-removal efficiency, microbial community composition, and predicted metabolic responses of anammox granular sludge. Results showed that 12mg/L Cu(II) induced a temporary inhibition of anammox activity. In contrast, 8mg/L Cr(VI) caused a near-complete cessation of nitrogen removal. High concentrations of Cu(II) and Cr(VI) decreased the relative abundance of Candidatus Kuenenia by 4.86% and 2.88%, respectively, indicating that heavy metals likely impair anammox performance by directly inhibiting key anammox bacteria. Functional-prediction analysis (PICRUSt2) suggested that, under Cu(II) and Cr(VI) stress, the anammox community upregulated pathways associated with cell motility, energy metabolism, chemotaxis, signal transduction, and xenobiotic biodegradation—presumably as adaptive responses to mitigate toxicity.

To explore the influence of trace elements and change in environmental conditions at low temperature on the nitrification performance of biofilm reactor, a simulated wastewater containing NH₄⁺-N was treated. The effects of trace elements, low temperature, aeration rate and flow rate on nitrification performance of the biofilm reactor were studied. The microbial community structure was analyzed by 16S rRNA high-throughput sequencing technique. The results showed that trace elements significantly affected the nitrification performance (P<0.0001). After adding trace elements to the influent, the removal load of NH₄⁺-N increased from 0.93kg/(m³·d) to 1.63kg/(m³·d) and the generation load of NO₃^--N increased from 0.23kg/(m³·d) to 1.21kg/(m³·d). Low temperature can affect nitrifying bacteria. Nitrite oxidizing bacteria (NOB) are sensitive to low temperature shock, while ammonia oxidizing bacteria (AOB) are resistant to it. The decrease in aeration rate led to a lack of dissolved oxygen (DO) in the reactor, which further affected the nitrification performance. The change in flow rate had no significant effect on the nitrification performance. Analysis of the microbial community structure at low temperatures showed that the nitrobacteria of Nitrosomonas and Nitrospira were enriched during operation, which ensured that the reactor can still have stable nitrification performance. The research provides experimental evidence and theoretical guidance for improving the nitrification performance and enhancing the low-temperature resistance of biofilm reactor in wastewater nitrification treatment practice.

An anaerobic sequencing batch biofilm reactor was used to explore the combined effect mechanism of anammox under the co-existence conditions of quinoline (50~200mg/L) and microplastics (PET-MPs) (20~100mg/L). With the increase of the concentrations of quinoline and PET-MPs, the performance of Anammox first decreases and then gradually recovers, and recovery time of reversible inhibition was positively correlated with the concentration of combined pollutants. The specific anammox activity (SAA) decreased from 22.8mg N/(g VSS·h) in stage C1 to 16.2mg N/(g VSS·h) in stage C3, while the corresponding reactive oxygen species (ROS) production increased by 55.7%, indicating that the inhibition of Anammox was enhanced under combined pollution. Extracellular polymer (EPS) analysis revealed that an increase in the concentrations of quinoline and PET-MPs would lead to a rapid decrease in the EPS content of the biofilm from 75.3mg/g VSS to 39.2mg/g VSS. The significant reduction in protein (PN) secretion, which in turn led to a significant decrease in PN/PS, indicates a decline in the structural stability of the Anammox biofilm. High-throughput sequencing revealed that the concentration of quinoline /PET-MPs increased, while the microbial community diversity and richness indices decreased. The relative abundance of Candidatus_Brocadia decreased from 1.73% to 1.24%, while the relative abundance of Denitratisoma changed little. However, the relative abundance of anaerobic heterocyclic degrading bacteria increased significantly.

The study used humic acid (HA) to drive the potassium permanganate/persulfate (PM/PMS+HA) system to investigate the removal of small molecule organic pollutants and the effectiveness of membrane fouling control. The experimental results showed that the PM/PMS+HA system exhibited excellent removal performance for different small molecule organic compounds, including Atrazine (ATZ), Phenol (Phenol), Diclofenac Sodium (DCF), Carbamazepine (CBZ), Ibuprofen (IBP) and Sulfamethoxazole (SMX). The first-order kinetic constants of the PM/PMS+HA system were all higher than 18×10^-2min^-1, far higher than the PM/PMS system, PM system, and ultrafiltration system alone. At the same time, the PM/PMS system has a good membrane fouling alleviation effect. When HA was used as the pollutant, the effluent specific flux of the PM/PMS system only decreased to 0.919 within 15 minutes, much higher than the 0.393 obtained by HA filtration alone. Meanwhile, when using the PM/PMS system for membrane cleaning, the membrane flux recovery rate reached 98.51%. The mechanism of the PM/PMS+HA system was explored through capture experiments and measurements using a UV spectrophotometer. The experimental results indicate that during the filtration process of PM/PMS+HA, it is mainly the rich electronic HA in the system that triggers the decomposition of the composite oxidant (PM-PMS). The decompositionof composite oxidants produces reactive oxygen species (^•OH、SO₄^•-、¹O₂) and reactive manganese(Mn(V)and Mn(VI)). The generated reactive oxygen species and reactive manganese oxidize pollutants, leading to the removal of new pollutants and a decrease in the molecular weight of membrane pollutants, thereby achieving the removal of new pollutants and the control of membrane pollution. The PM/PMS system driven by pollutants has achieved the coupling of ultrafiltration membranes with advanced oxidation technology, providing new ideas for the removal of small molecule organic compounds and membrane fouling control in ultrafiltration technology.

This study investigated the effects of raw water turbidity variation on the stable flux, pollutants removal, and bio-cake layer of gravity flow ultrafiltration (GDM) system. The results showed that the increase of raw water turbidity led to a significant decrease in the flux of GDM system, but a new stable flux can be achieved in 17~30 days. Compared to control GDM with low influent turbidity (1.8~3.7NTU), the increase of raw water turbidity to 10, 50 and 100 NTU reduced the stable flux of GDM system by 15%, 36% and 61%, respectively. The macromolecular organic matter carried by particles was degraded by microorganisms in the bio-cake layer to low molecular weight organic matter, which passed through the membrane and resulted in increase of dissolved organic matter in the effluent with the increase of raw water turbidity. The ammonia removal rate of GDM system reached more than 80% after 9days of start-up, and the temporary decrease in ammonia nitrogen removal capacity occurred due to the increase of raw water turbidity. However, it recovered after 7~11days of adaptation period. With the increase of raw water turbidity, the thickness of bio-cake layer increased by 1.8 to 7.9 times and the microbial extracellular polymeric substances increased by 37 to 98%. Meanwhile, the microbial community structure underwent certain changes. This study shows that GDM system has certain adaptability to increase of raw water turbidity.

A novel catalytic membrane (AC-MgO@PVDF) was fabricated by loading activated carbon (AC) and MgO onto a poly (vinylidene fluoride) (PVDF) membrane using a vacuum filtration method. The as-prepared catalytic membrane (AC-MgO@PVDF) was employed to activate persulfate (PS) for the oxidation of ammonia nitrogen (NH₄⁺-N) in aqueous solution. The structure and elemental composition of the catalytic membrane were characterized by SEM, Raman and XPS. The efficiency and mechanism of NH₄⁺-N oxidation by the AC-MgO@PVDF/PS system were investigated. The results showed that under the conditions of a flow rate of 1mL/min, a PS dosage of 8g/L and an AC loading of 4.8mg/cm², the removal rate of 30mg N/L NH₄⁺-N and the nitrogen gas (N₂) selectivity of the NH₄⁺-N oxidation products reached 100% and 91.7%, respectively, after 25min of operation. The system exhibited a broad pH tolerance range (3~12) and was barely affected by common anions and natural organic matters in water body. Even after 240min of continuous operation, the system could still achieve a removal rate of over 60% for NH₄⁺-N. Quenching experiments, EPR measurements, and electrochemical tests revealed that f NH₄⁺-N was primarily oxidized through a non-radical pathway, with direct electron transfer being the main mechanism for its oxidation to N₂.

This study implemented an integrated precipitation-air stripping-electrochemical oxidation process to treat limestone wet desulfurization wastewater, systematically investigating the effects of operational parameters on chloride removal, nitrogen elimination, and organic pollutant degradation. The removal mechanisms of multiple contaminants were comprehensively elucidated. Through response surface methodology (RSM) optimization, the salt precipitation achieved 66.9% chloride ion removal efficiency under optimal conditions (Ca/Al/Cl molar ratio of 6.8:1.9:1, operational temperature 37.5℃). Air stripping was conducted under alkaline condition, which attained 76.5% ammonia nitrogen removal efficiency. Finally, after 180min electrochemical oxidation, the effluent ammonia nitrogen and COD concentrations were significantly reduced to 7mg/Land 165mg/L, respectively. Mechanistic analysis revealed that the introduction of calcium-aluminum salts facilitated the transformation of tetrahedral Al(OH)₄^- into Ca-O-Al octahedral under high Ca/Al ratios and appropriate thermal conditions. Cl^- were immobilized through adsorption or ion exchange by calcium-aluminum bimetallic layered hydroxide, then the Ca₄Al₂(OH)₁₂Cl₂•10H₂O was formed and precipitated from the water. After precipitation-air stripping process, the residual Cl^- concentration in the effluent was high, enabling its participation in electrochemical activation, and generating reactive species such as •Cl, •OH and ¹O₂, Thus those pollutants such as ammonia nitrogen and organic matters in the effluent was efficiently purified by direct anodic oxidation and indirect oxidation of active substances.

In view of the typically unsatisfactory antibiotics removal performances that were observed in the traditional 'three ponds and two dams' combination process, a new composite packing filter dam was developed. Through the synergetic combination of composite packing balls with a specially designed filter dam structure, highly efficient and broad-spectrum removal of antibiotics was achieved. Results showed that the removal rates of antibiotics (in terms of total mass concentrations) in perch, eel, raw fish and shrimp culture pond water were maintained at more than 80% by the composite packing filter dam. Quinolones, sulphonamides, tetracyclines and chloramphenicol were removed to different extents, among which the best removal effects were observed for quinolones and sulphonamides. The composite filler consisting of iron filings, ceramsites and polybutylene succinate (PBS) was found to significantly improve the removal of quinolones and sulfonamides. Ceramsites were demonstrated to play an adsorption role through which quinolone and sulfonamide antibiotics were removed via pore filling and π-π electron donor-acceptor interactions, which was identified as the main antibiotic removal pathway. Iron filings were shown to remove tetracycline and chloramphenicol through adsorption and reduction processes, and were suggested to have accelerated the direct electron transfer process that promoted antibiotic degradation. PBS was involved in the removal of antibiotics through co-metabolic denitrification. Both iron filings and PBS were proven to enhance the metabolic activity of functional microorganisms, thereby accelerating antibiotic removal. The synergistic effect between these components was confirmed to help achieve efficient and broad-spectrum antibiotic removal.

The reed biochar was chemically modified using hydrochloric acid, dicyandiamide, and magnesium chloride as activators. This study investigated the effects of varying pH values, addition amounts, and initial solution concentrations on the nitrate nitrogen adsorption capacity of four types of biochar. Additionally, the adsorption kinetics and thermodynamic characteristics of the biochars for nitrate nitrogen removal were analyzed. When reed straw is pre-carbonized at 500℃ for 2hours and subsequently activated with modified materials at 700℃ for 2hours, the resultant dicyandiamide-modified biochar (DBC) exhibits the best adsorption performance, achieving a removal efficiency of 75.5%. Compared to unmodified biochar (BC), the surface morphology of the modified biochars becomes more concave, with denser pores, increased functional groups, and a specific surface area enhanced by 7 to 10 times. When the potassium nitrate concentration is 500mg/L, the optimal dosages are 1g for BC, DBC, and magnesium chloride-modified biochar (MBC), and 0.8g for hydrochloric acid-modified biochar (HBC). The nitrate nitrogen adsorption performance of DBC is favorable in a slightly alkaline environment, with the highest adsorption capacity observed at a pH of 9. The nitrate nitrogen adsorption behavior of all four biochars aligns well with the pseudo-second-order kinetic model, and their isothermal adsorption curves fit the Langmuir equation, suggesting predominantly monomolecular layer adsorption. Overall, DBC demonstrates excellent nitrate nitrogen adsorption performance and offers a promising solution for mitigating nitrate pollution in aquatic environments.

In this study, a method for control of humic acid-cadmium composite pollution using MXene/PMS process in the presence of trace Fe(III) was proposed. The results showed that the removal efficiency of Cd²⁺ by MXene material in the presence of humic acid decreased from 70% to 48%, and addition of 0.5µmol/L Fe(III) and 50µmol/L peroxymonosulfate increased the removal efficiency of Cd²⁺ to above 60%. too much or less PMS inhibited the removal of Cd²⁺. Reducing Fe(III) from 1.0µmol/L to 0.3µmol/L promoted the removal of Cd²⁺. The strong reducing property of MXene material and its strong interaction with metal ions triggered the Fe(III)/Fe(II) cycle and inhibited the hydrolysis of iron ions, realizing the efficient removal of humic acid-cadmium composite pollution under neutral conditions. The reactive species generated in the reaction system were mainly hydroxyl radicals and sulfate radicals. Under the background condition of Xijiang river, this technique maintained good removal effect.

The removal efficiency of glyphosate may be affected due to the quenching process of radicals by in-situ produced inorganic phosphorous. To address the problem, we have developed a novel approach to achieve the direct electron transfer between glyphosate and PMS by adding NaOH to adjust the pH values. The effectiveness and mechanisms of glyphosate degradation in various NaOH concentration were evaluated by several experiments: optimizing the concentrations of reactants, radical trapping tests, and electron paramagnetic resonance (EPR) characterization. Varying pH could change the morphologies of glyphosate and PMS, as a result, accompanied the various glyphosate removal rate. Under alkaline condition, the mechanisms of glyphosate degradation depended on the direct electron transfer process, and insignificant contribution of hydroxyl and sulfate radicals. Thus, it effectively prevented the negative effects on radical oxidation by produced inorganic phosphorous during glyphosate removal processes. As a result, glyphosate (10mg/L) was completely decomposed after five minutes with the addition of 5mmol/L PMS and 6mmol/L NaOH.

Based on the acidic and phosphorus-rich properties of phosphogypsum (PG), it was dope-modified (PO-PG) to cement (PO) and used for lead removal from acid mine wastewater. The results showed that PO-PG removed more than 99% of lead at different concentrations (15~100mg/L) with suitable dosage; under the reaction conditions of initial pH=3, PO-PG dosage of 0.2g/L, and 25℃, the effect of PO-PG on the removal of lead from 30mg/L Pb²⁺ was completely removed in 20min instead of 120min for PO; meanwhile, PO-PG had a high affinity for lead, and the removal effect of lead remained stable in the simulated wastewater with complex composition. Mechanistic analysis showed that isomorphous replacement and surface heterogeneous chemical precipitation were the main mechanisms for lead removal by PO-PG, Ca(OH)₂, CaCO₃ and Ca₅(PO₃)₃ OH were the main lead removal factors in PO-PG, and Pb²⁺ is removed by lattice displacement and other chemical reactions with Ca²⁺ to form a water-insoluble precipitate, and the products of the lead removal mainly included PbCO₃, Pb₃(CO₃)₂(OH)₂, Pb(OH)₂ and Pb₅(PO₄)₃ OH precipitates. In summary, the doping of acidic PG can accelerate the hydration rate of alkaline PO, thus improving the reaction efficiency and alleviating the problem of high pH in PO-treated effluent, in addition to the presence of phosphates in PG can be an effective species for lead removal. This study provides a cost-effective and efficient new method for the removal of lead from acid mine wastewater and can realize the resource utilization of phosphogypsum.

Sulfate radical (SO₄^•−)-based advanced oxidation processes (SR-AOPs) are characterized by in situ generation of SO₄^•− with strong oxidation capacity, which can effectively degrade a variety of organic pollutants. However, SO₄^•− can transform nitrite (NO₂⁻) and bromide (Br⁻) into toxic nitrated byproducts and halogenated byproducts, respectively. In this study, the mechanisms underlying the formation of nitrated and brominated byproducts on the reaction system in which NO₂⁻ and Br⁻ coexist were systematically investigated. Results showed that three nitrated byproducts, including 2-nitrophenol, 4-nitrophenol, and 2,4-dinitrophenol were produced during the heat-activated persulfate nitrification process. It was observed that nitrophenols accounted for approximately 34.5% of the phenol transformed under reaction conditions of [phenol]= 50µmol/L, [NO₂⁻]=100µmol/L,[PDS]=2mmol/L and temperature of 60℃ C. Once NO₂⁻ was co-present, the formation rate of nitrophenol was significantly accelerated. The conversion rate increased to 46.0% under the same conditions. Br⁻ can be oxidized by SO₄^•− to form reactive bromine species, which rapidly react with NO₂⁻ to form a strong oxidizing agent, nitryl halide. Then nitryl halide reacts with the phenol and plays a key role in promoting the formation of nitrophenol. Note that, Br⁻ is eventually released and acts as a catalyst equivalent. Meanwhile, the presence of NO₂⁻ results in an inhibition of the rate of formation of brominated byproducts, such as dibromoacetic acid. Therefore, the transformation mechanisms of NO₂⁻ and Br⁻ influence each other in SR-AOPs. When they coexist, promote the formation of nitrophenol byproducts but inhibit brominated byproducts.

In order to clarify the interference effect of multiple coexisting pollutants on the degradation of target pollutants during the irradiation treatment process of complex wastewater, a multivariate pollution model was constructed according to the composition of typical antibiotic wastewater, and radiolytic degradation experiments under different conditions were designed. The results showed that ionizing irradiation could effectively improve the water quality of cephalosporin antibiotic wastewater. After irradiation at 5kGy, the COD and TOC of the pollution model decreased by 15.4% and 13.9%, respectively. The degradation percentage of the target pollutant cefotaxime sodium (CTX) in pure aqueous solution reached more than 93%. The coexisting compounds in the pollution model all have a certain degree of interference effect on the radiolytic degradation of CTX, and there is no significant correlation between the intensity of the interference effect and the relative concentration. After irradiation at 5kGy, the degradation percentage of CTX in the pollution model was 11.8% lower than that in pure water. There were differences in the interference modes of CTX degradation when the coexisting substances existed alone (binary model) and at the same time (multivariate model). Benzothiazole, thiourea and MIBK had the greatest influence on the degradation of CTX when existing alone, of which the interference effects Δk_p were 0.18, 0.14 and 0.12, respectively; while thiourea, benzothiazole and xylene had the greatest interference effect on the degradation of CTX when existing simultaneously, the de-interference effect Δk_n were 0.22、0.17 and 0.03, respectively. The sequence of the reaction between different compounds and free radicals and the interaction between the coexisting substances have a significant effect on the degradation of CTX.

We systematically investigated the effects of two model foulants, sodium alginate (SA) and bovine serum albumin (BSA), on the efficiency of the PRO process and organic fouling behavior on both sides of the membrane when natural seawater was used as the draw solution. The presence of foulants in the feed solution led to the flux reduction caused by the fouling within the support layer, in which the fluxes of SA and BSA decreased by 42.54% and 30.99%, respectively. When filtering BSA with smaller particle size instead of SA, it led to a more significant membrane fouling due to the blockage of internal pores in the support layer. The flux was 10.08% lower in SA filtration compared to BSA in the presence of model foulants in the draw solution, with fouling behavior primarily existed on the membrane surface. According to the XDLVO theory, the interfacial energy barrier of SA towards the feed solution side was lower than that towards the support layer side, leading to less repulsion with the active layer side of the membrane and increased membrane fouling. Conversely, BSA showed lower repulsion towards the membrane support layer side, suggesting that BSA existed on the feed solution side lead to more significant membrane fouling behavior, resulting in greater flux loss.

Box-Behnken response surface methodology (BBD-RSM) and back propagation artificial neural network (BP-ANN) algorithms were used to model and predict the process parameters (contact time, initial concentration, temperature, pH) of activated carbon adsorption of total phosphorus (TP), and the reaction conditions in the BP-ANN model were optimized in combination with genetic algorithms (GA). The results showed that in the BBD-RSM model, the P<0.0001, which could better predict the TP removal process, and contact time was the most significant parameter for TP removal, with the relative influence order of the factors in the TP adsorption process being: contact time > pH > temperature > initial concentration. The BP-ANN model was used for optimization, and the optimal network structure was 4-8-1. Sensitivity analysis showed that the factors affecting the TP removal rate were ranked as contact time (34.05%) > pH (28.67%) > temperature (19.56%) > initial concentration (17.72%). Based on the BP-ANN model, the GA was used to optimize the operating conditions of the artificial percolation system, and the optimization results for the TP removal process were: contact time of 720.53min, initial concentration of 2.75mg/L, temperature of 30.62℃, and pH value of 5, achieving the optimal removal rate (99.63%). Experimental validation analysis showed that BP-ANN-GA had a higher R² (0.9939) and lower RMSE (1.2851) compared with BBD-RSM when predicting against the experimental values, indicating that this model had better predictive ability and could better describe the TP removal process in the constructed rapid infiltration (CRI) system.

Based on water quality indicators, climate indicators, and wetland operation parameters, data from previous studies were collected to predict the effluent concentrations of ammonia nitrogen (NH₄⁺-N), COD, sulfamethoxazole (SMX), and some heavy metals in constructed wetlands using three machine learning models. The results showed that the Random Forest model slightly outperformed XGBoost and LightGBM in overall performance, demonstrating more stable R² and RMSE values. In particular, it achieved higher accuracy in predicting NH₄⁺-N and SMX concentrations, with R² values of 0.93, 0.89, and 0.87, respectively, for NH₄⁺-N. In contrast, the models performed relatively weaker in COD predictions, with R² values of 0.71, 0.61, and 0.64, respectively. By incorporating the SMOTE data augmentation technique, the prediction performance and accuracy of the models were significantly enhanced, especially for COD, where improvements ranged from 7.04% to 26.23%. This study combines scientific data analysis with machine learning algorithms, providing a feasible approach for practical engineering applications.

This study investigated the regulatory mechanisms of zero-valent iron-graphite composite materials (0~4.0g/L) on sludge fermentation via chain elongation(CE) systems through a gradient dosing approach. The enhancement of iron-carbon materials on the CE process were systematically analyzed by monitoring the variations of short-chain carboxylic acids (SCCAs) and medium-chain carboxylic acids (MCCAs) concentrations, decomposition and metabolism of organics, electron transfer efficiency, and evolution of microbial community structure. The results demonstrated that the MCCAs production reached 10.65g/L at an iron-carbon dosage of 0.5g/L, representing a 2.04-fold increasement compared to the control group. The selectivity of caproic acid reached 53.60%, enhanced by 24.96% compared to the control. Mechanistic studies revealed that iron-carbon materials influenced the three stages of anaerobic fermentation (solubilization, hydrolysis, and acidification), promoting the decomposition and metabolism of organics and the conversion of polysaccharides to SCCAs. Simultaneously, a significant enhancement in electron transfer activity was observed in the groups with iron-carbon addition. Microbial community analysis further indicated that iron-carbon materials increased the relative abundance of the phylum Firmicutes and the genus Clostridium sensu stricto 12, which facilitated hydrolysis and CE processes in anaerobic fermentation. This study suggested that the application of iron-carbon materials could enhance MCCAs production in sludge anaerobic fermentation systems.

This study systematically investigated the synergistic interactions between biochar and the model electroactive microorganism Shewanella oneidensis MR-1 in electron transfer processes through comprehensive electrochemical analyses, kinetic modeling, and electron pathway characterization using chromium(VI)-contaminated soil as the experimental matrix. The biochar-based microbial agents demonstrated effective Cr(VI) bioremediation, with biological reduction mediated by MR-1identified as the predominant mechanism following dual-process kinetics. Optimal remediation performance (96.30% Cr(VI) reduction efficiency) was achieved under conditions of 25mg/kg Cr(VI) contamination, 5% (w/w) biochar-based microbial agents dosage, and 30% soil moisture content. Comparative analysis revealed distinct temporal remediation patterns: adsorption-based biochar-microbial composites exhibited rapid initial Cr(VI) sequestration but limited long-term stability, whereas encapsulation-based formulations showed gradual but sustained reduction capacity. Mechanistic studies demonstrated that biochar functioned as an effective microbial carrier, simultaneously enhancing MR-1proliferation and facilitating extracellular electron transfer from microbial cells to Cr(VI) contaminants through its conductive carbon matrix. Notably, the immobilized system maintained 60.44% reduction efficiency after three operational cycles, highlighting its potential for sustainable in situ remediation of chromium-contaminated soils.

In this study, we measured the contents of P in various forms in the topsoil (0~10cm) of 8representative pine (Pinus massoniana) forests in the main urban area of Chongqing. We used high-throughput sequencing technology to investigate the community characteristics of the phoD-harboring bacteria. The results showed that the surface soils of Pinus massoniana forests in the study area had relatively low phosphorus levels, with average total phosphorus (TP) contents of 192.787mg/kg in winter and 169.512mg/kg in summer. Among the inorganic phosphorus fractions, the content distribution followed the order: occluded phosphorus (O-P) > iron-bound phosphorus (Fe-P) > aluminum-bound phosphorus (Al-P) > calcium-bound phosphorus (Ca-P) > exchangeable phosphorus (Ex-P), showing a seasonal pattern of higher levels in winter and lower levels in summer. The dominant phyla of phoD-harboring bacteria in the soil were Proteobacteria, Actinobacteria, and Planctomycetes, collectively accounting for 96% of the average relative abundance. Correlation analysis showed a significant negative correlation (P<0.05) between the diversity of phoD-harboring bacteria and Al-P, as well as a significant positive correlation (P<0.05) with soil pH. Redundancy analysis indicated that Al-P and pH were the most important factors influencing the community structure of phoD-harboring bacteria. In conclusion, the topsoil of pine forests in the main urban area of Chongqing is generally P-deficient, and the P content is significantly influenced by season. The forms of P occurrence affect the community structure and diversity of phoD-harboring bacteria.

Packed column experiments and numerical simulations were conducted to investigate the co-transport behavior of nanoscale iron supported on biochar (nFe/BC) pyrolyzed at 500℃ and 800℃, respectively, with arsenic (As) in contaminated soil. The results showed that the mobility of nFe/BC (nFe/BC500 and nFe/BC800) in As-contaminated soil was obviously lower than that of pristine biochars (BC500 and BC800), decreasing by about 57.8% and 45.5% in As-contaminated soil, respectively. This is likely because zeta potentials of nFe/BC became less negative due to the adherence of positively charged Fe onto the BC. Therefore, electrostatic repulsion between nFe/BC and soil grain was weakened, resulting in a lower mobility of nFe/BC. Also the mobility of nFe/BC was reduced with an increase in pyrolysis temperature. This is likely because that the surface charge of nFe/BC produced at high temperature was less negative, due to the lower density of O-containing functional groups. Therefore, the total repulsive interaction energies between nFe/BC and soil grain were reduced. A two-site kinetic retention model was successfully employed to simulate the transport of nFe/BC in soils, further illustrating the co-transport characteristics of nFe/BC. Additionally, pristine BCs facilitated the transport of As due to the competition between BCs and As for the available sorption sites on the soil surface. However, nFe/BC first inhibited the transport of As, and then promoted it. The main reason could be because the iron substance or Fe₃O₄ on the surface of nFe/BC reacted with As, and then fixed it in soil. Once the reaction between nFe/BC and As was completed, nFe/BC lost its original inhibitory effect, and instead acted as a carrier to promote As transport in soil. This could cause potential risks of As to the groundwater environment.

This paper aims to review the global research progress and emerging hotspots related to plastic pollution in marine and inland water from 2008 to 2023, based on data from the Web of Science and CNKI databases. A total of 13872 articles were selected and analyzed, with the majority of studies conducted in analytical methods and monitoring techniques. The findings emphasize that discharge and non-degradable nature of plastic waste are the main drivers of pollution in these aquatic environments. Increasing global attention has been directed toward this issue, as reflected in the growing number of publications since 2020. At present, mainstream analytical methods for studying plastic pollution include microscopic observation, Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy. However, field sampling efforts remain limited, with challenges such as varying mesh sizes used in trawl nets affecting data consistency. To address these limitations, future research should utilize unmanned aerial vehicles (UAVs) and advanced remote sensing technologies for monitoring plastic pollution. It should also explore the potential integration of satellite, aerial, and ground-based remote sensing into a multi-scale, comprehensive monitoring system, providing scientific insights and practical recommendations for advancing plastic pollution research and management.

The distribution characteristics of benzene, toluene, ethylbenzene and xylene (BTEX) concentrations in seawater and the atmosphere in the East China Sea in October 2020 were investigated, the sea-air exchange fluxes were evaluated, and the ecological risks and environmental effects were analyzed. The results showed the average concentrations of benzene, toluene, ethylbenzene, m/p-xylene and o-xylene were (136.8±76.8), (321.3±279.0), (530.3±530.0), (336.2±453.6) and (493.7±814.7) pmol/L in the surface seawater, respectively, and were (122.3±84.2), (217.1±162.4), (423.8±399.0), (236.8±215.1) and (344.3±288.5) pmol/L in the bottom seawater. The high values were found in the nearshore and the eastern part of the investigated sea area, of which the high values in the nearshore indicated they were influenced by land-based inputs, and the high values in the eastern part might be related to the petroleum extraction activities. The average atmospheric concentrations of benzene, toluene, ethylbenzene, m-/p-xylene and o-xylene were (110.5±45.3),(410.1±384.4), (139.5±108.8), (128.3±123.9) and (108.9±97.6) ×10^-12, and the backward trajectories showed they were affected by the input from land-based sources. The mean sea-air fluxes of benzene, toluene, ethylbenzene, m-/p-xylene and o-xylene were (25.6±13.1),(73.1±78.2), (179.9±194.5), (146.3±185.4), and (216.3±358.7) g/(km²⋅d), indicating that the investigated sea area is an important source of atmospheric. In terms of ecological risk, the concentrations of BTEX in seawater were far below the acute toxicity median effect concentration (EC50) and the half-lethal concentration (LC50) for marine organisms, indicating that BTEX posed relatively low direct harm to segmental marine life. In the atmosphere, the calculated carcinogenicity risk value (R), the non-carcinogenicity risk hazard quotient (HQ), and the non-carcinogenicity risk index (HI) were much lower than the reference values, indicating that the direct threat of atmospheric BTEX to human health was low. The analysis of O₃ and SOA generation potentials revealed that toluene and xylene were the key active components of BTEX and had the most significant impact on environmental effects.

This study focuses on five typical lakes in cold-arid areas, analyzing the phosphorus pool capacity and phosphorus migration dynamics of sediments using methods such as phosphorus fractionation, diffusive gradients in thin films (DGT), and the DGT Induced Fluxes in Sediments model (DIFS). Partial least squares path modeling (PLS-PM) was further employed to identify the key driving factors for the endogenous phosphorus pool capacity and migration dynamics in these lakes. The results showed that the average values of total phosphorus (TP_w), total nitrogen (TN_w), and nitrogen-to-phosphorus ratio (TN_w/TP_w) in the water of the five lakes were (0.81 ± 1.31)mg/L, (3.40 ± 1.87)mg/L, and (26.13 ± 22.75), respectively, indicating that these were phosphorus-limited lakes. The average total phosphorus (TP_s) content in surface sediments was (763.48 ± 563.70)mg/kg, with calcium-bound phosphorus (Ca-P) accounting for 51.09% of the TP_s. The comprehensive pollution index (FF) values for sediments indicate a severe pollution level. The biologically available phosphorus (BAP) dissolved active phosphorus (C_DGT-P), and distribution coefficient (K_d) average (193.54 ± 55.94)mg/kg, (0.19 ± 0.14)mg/L, and (11.34 ± 9.29)cm³/g, respectively. All three indicators of phosphorus pool capacity were lower than those in lakes of the eastern plains, reflecting a relatively low phosphorus reservoir capacity in cold and arid lakes. The DIFS model shows that the reaction time (T_c) of the five lakes ranges from 0.004 to 74, 170s, lower than that of lakes in the eastern plains, indicating slower phosphorus migration dynamics and a relatively lower supply rate to the water body. PLS-PM analysis reveals that the primary factor influencing phosphorus reservoir capacity in these lakes was sediment properties (0.64,P<0.05). The main factor influencing phosphorus migration dynamics (0.95, P<0.05) was the environmental conditions of the water bodies, with limited influence from lake trophic state and phytoplankton.

Taking the Pengxi River, a typical tributary bay of the Three Gorges Reservoir, as an example, continuous monitoring of the water flow, water quality, and algal bloom in the bay during the drawdown period in 2023 was carried out. The hydrodynamics, thermal stratification, and water quality evolution patterns of the tributary bay were analyzed, and the occurrence, disappearance, and influencing factors of algal blooms were revealed. The results show that during the observation period, the chlorophyll a of phytoplankton in the Pengxi River bay was positively correlated with water temperature (r=0.43, P<0.05) and euphotic layer depth (r=0.38, P<0.05), and negatively correlated with upstream inflow (r=-0.53), flow velocity (r=-0.54), and mixed layer depth Z_mix (r =-0.37). However, nutrients were not the limiting factors for the occurrence and disappearance of algal blooms. When the water temperature was suitable and the thermal stratification was stable, algal blooms began to occur. A gradual water level drawdown (<0.2m/day) fails to notably enhance flow velocity or break thermal stratification in the bay, resulting in minimal suppression of algal blooms in tributary bays. During the drawdown period, rainfall and upstream inflow could significantly affect the hydrodynamic processes and nutrient levels in the bay, which were the key factors determining the occurrence and disappearance of algal blooms in Gaoyang Lake. Increasing the discharge flow from Hanfeng Lake (>80m³/s)could effectively control algal blooms in the Pengxi River bay.

This study involved the collection and analysis of bacteria and fungi samples in water and sediment from ten typical sub-lakes of Poyang Lake. A hydrological connectivity index system for sub-lakes was established to quantitatively assess the effect of hydrological connectivity on microbial community structure. The results indicate significant differences in the α-diversity of water bacteria, sediment bacteria, and fungal communities during different stages of the dry season, sediment bacteria and fungi showed higher α-diversity during the mid-dry season. The difference in β diversity of water bacterial community was more obvious in different periods, and the β diversity of sediment bacterial and fungal communities showed spatial differences. With the increase of hydrological connectivity, the similarity of sediment bacterial and fungal communities was lower. The water area ratio (WSP) and water depth (WD) were the main hydrological connectivity variables affecting the water bacterial community structure. Lake basin elevation (LE) and WD were the main hydrological connectivity variables affecting sediment bacteria and fungi community structure. Hydrological connectivity explained less variation in water bacterial community structure (7.6%) compared to sediment bacteria (33.3%) and fungal (29.7%) community structures. The co-interpretation rate of hydrological connectivity and physicochemical factors on bacterial community structure in water was only 2.4%, and the co-interpretation rates of bacterial and fungal community structure in sediments were 9.7% and 6.2%, respectively. Sediment bacterial and fungal communities were predominantly shaped by stochastic and deterministic processes, respectively, while both processes jointly influenced water bacterial communities. Under moderate hydrological connectivity, water bacterial communities showed stronger stochastic processes, whereas as connectivity increased, stochastic processes in sediment bacteria and fungi weakened.

In order to analyse the response of bacterial community structure to the abundance of nitrogen (N) and phosphorus (P) metabolic functions in different water depths of lakes, this paper presents a characterization of the spatial distribution and correlation of bacterial community structure and the abundance of N and P related metabolic functions in the surface, middle and bottom waterbodies by high-throughput sequencing technology, with Lake Dali as the object of the study. The results showed that the composition of the dominant bacterial communities in the surface, middle and bottom water layers varied significantly with the changes in the physical and chemical properties of the water. Based on the ecological network, the dominant and important genera under the first five dominant phyla were analysed under the screening criteria of degree and abundance values, and the dominant genera in the different depths of Lake Dali were significantly changed, such as three genera in the surface and middle water, and two genera in the bottom water. Comparatively, CL500-29_marine_group and Thermus in the surface water, Synechococcus and norank_o__NB1-n in the middle water, and Synechococcus、norank_o__NB1-n、norank_f__CK06-06-Mud-MAS4B-21 in the bottom water, remained consistent with the two screening criteria. Further PICRUSt2 prediction of the functional composition of the bacterial community yielded 6 primary functions and 12 secondary metabolic functions. In particular, although Pseudomonas,Paracoccus and Synechococcus showed significant positive correlation with the abundance of N and P metabolic functions, the correlation with the N and P content of different forms was different, such as Pseudomonas showed positive correlation with the change of N and P content, Paracoccus showed negative correlation with the N and P content, and Synechococcus showed negative correlation with N and positive correlation with P elements. Overall, the differences in N and P contents caused by changes in water depth had significant effects on N and P metabolism and the dominant genera.

To investigate the effects of water flow disturbances on the growth and aggregation characteristics of Microcystis blooms, this study conducted controlled indoor experiments in a flume, with disturbance frequencies set at 30, 40, 50, and 60min^-1. The growth dynamics and size variation of Microcystis colonies were systematically analyzed under varying disturbance conditions. The results showed that low-intensity water flow disturbances (frequency<40min^-1 or velocity<0.026m/s) significantly promote the secretion of extracellular polymeric substances (EPS) in Microcystis, with a strong correlation observed between Chlorophyll-a and EPS concentrations (r²>0.85). Conversely, high-intensity disturbances (frequency>50min^-1 or velocity>0.034m/s) inhibited EPS secretion, leading to a weakened correlation between Chlorophyll-a and EPS concentrations (r²<0.8). Within the experimental ranges of flow velocity (0~0.08m/s) and turbulent kinetic energy (0~0.004m²/s²), the size of Microcystis colonies exhibited minimal variation (ranging from 0.4~0.6mm). Furthermore, low-intensity disturbances facilitated the formation of surface blooms with shorter durations, whereas higher-intensity disturbances suppressed bloom aggregation while extending algal survival periods.

A typical urban lake (Xinghu Lake) in the Guangdong Hong Kong Macao Greater Bay Area was selected as the study area, and the density flotation method was used to extract microplastics from surface sediments. The spatiotemporal occurrence characteristics of microplastic were presented, and the potential ecological risks of microplastic were revealed, and the spatial autocorrelation of microplastic abundance was analyzed. The results showed that the average abundances of microplastic in surface sediments of Xinghu Lake were (637±392) and (1765±883) particles/kg during the wet and dry seasons, respectively. Here, the colors of microplastic were mainly blue and black, lines were the dominant microplastic shapes, and the size of microplastic was concentrated in the range of 100 to 2000µm. Rayon, polypropylene, and polyethylene terephthalate were the main polymer types of microplastic in surface sediments of Xinghu Lake during the wet and dry seasons. The abundances of microplastic in surface sediments of Xinghu Lake showed a strong spatial autocorrelation during different seasons, and the sampling interval for microplastic should be less than 435m here. Meanwhile, the average comprehensive potential ecological risk indexes of microplastic in surface sediments of Xinghu Lake were 53.0 9and 344.08 during the wet and dry seasons, which were the slight and very strong risk levels, respectively. Furthermore, the potential ecological risks of rayon microplastics were relatively high.

To investigate the relative importance of the bottom-up versus top-down on phytoplankton biomass in the estuary and its adjacent waters of the Yellow River during the water and sediment regulation scheme (WSRS), the study utilized R2V software to extract historical data (2011~2020) on chlorophyll a (Chl a) concentration, environmental factors, and zooplankton abundance in the estuary and its adjacent waters of the Yellow River from the literature. The spatial distribution and interannual variation of Chl a concentration was analyzed, and regression tree models Chl a with environmental and biological factors at different stages of WSRS were developed to explore the controlling factors. The results showed that Chl a concentrations in the estuary and its adjacent waters of the Yellow River generally decreased from the estuary towards offshore areas from 2011 to 2020. As WSRS progressed, the high-value areas gradually shifted to the nearshore northwest of the estuary. Regions with significant interannual variations in Chl a concentrations largely overlapped with high-value areas at each stage. The regression tree model indicated that, with the progression of water and sediment regulation, there was a notable shift in the dominant effects on Chl a concentration. Before WSRS, the top-down effect of zooplankton grazing was the primary driver of Chl a spatial variability. During the water and sediment regulation period, Chl a concentration was mainly controlled by bottom-up effects. In the early WSRS, temperature was the primary driving factor, while in the later stage of WSRS, dissolved inorganic phosphorus (DIP) became the main driving factor. The changes in salinity fronts caused by freshwater flow during WSRS may be an important factor inducing changes in the dominant effects on Chl a concentration.

This study analysed the spatiotemporal characteristics of dissolved oxygen (DO) concentrations upstream and downstream of sluices during dry and wet years, using data from three automated water quality monitoring stations and field measurements along the Huangjiang River in Guangdong Province. Multiple statistical methods were employed to identify the relative contributions of key influencing factors to DO variability across years under different precipitation conditions. Upstream DO concentrations were generally higher in dry years ((8.02±0.10) mg/L) than in wet years ((7.26±0.08) mg/L). In contrast, DO levels in the downstream tidal section increased from (4.45±0.10) mg/L (dry year) to (7.33±0.09) mg/L (wet year), primarily due to improved water quality. Periodic fluctuations were observed in both years, with higher DO levels during the flood season and lower levels during the non-flood season throughout the river channel. Influenced by the gate control and different external inputs, DO fluctuations upstream and downstream were driven by different factors. Rainfall and water temperature explained 44% to 87% of the DO variability upstream. While ammonia nitrogen, and COD_Mn were the most influential factors downstream, accounting for 53% to 75% of the variability. Furthermore, the “lacustrine” upstream section was especially sensitive to climate variations. In this area, the loss of phytoplankton biomass caused by stormwater runoff was a major factor contributing to DO difference during dry and wet years. While DO downstream is more easily influenced by water pollutants, especially the significant decrease in oxygen-demanding substances.

This study developed an improved export coefficient model by integrating rainfall and topographic correction factors to estimate non-point source nitrogen and phosphorus pollution loads and identify key pollution sources in the Ganjiang River Basin. The accuracy of the original and modified models was systematically compared, and correlation analysis was performed between nitrogen and phosphorus load intensity and monitored concentration data. The results demonstrated an increasing trend in both total pollution loads and load intensities from 2016 to 2020. Total nitrogen and total phosphorus exports increased by 15.99% and 16.37%, respectively, while corresponding load intensities rose by 15.89% and 16.85%. Spatially, the pollution distribution exhibited a characteristic north-high-south-low pattern with localized concentration, indicating higher contamination risks in downstream areas. Land use emerged as the primary source of nitrogen pollution, contributing 51.65% of total nitrogen exports, whereas livestock farming was identified as the dominant phosphorus source, accounting for 36.82% of total phosphorus outputs. The enhanced export coefficient model demonstrated significantly reduced relative errors compared to the original version. Statistical analysis revealed significant correlations (P<0.05) between annual average nitrogen or phosphorus concentrations and load intensities, confirming the improved model's superior accuracy. The refined model enables more precise assessment of watershed non-point source pollution, facilitates identification of major pollution sources, and supports targeted delineation of critical control zones, thereby providing valuable scientific support for non-point source pollution management and remediation strategies in river basins.

A multi-phase extraction technology was implemented to reduce the source of pollutants within a large retired chemical area in Shanghai, prevent further diffusion, and lower the health and ecological risks associated with the pollutants, while simultaneously analyzing the characteristics of NAPLs under the influence of multi-phase extraction. Through monitoring pollutants in the shallow groundwater across the site, changes in the spatial distribution of pollutants in the aquifer under extraction influence were characterized and ecological risks were assessed. The study indicated that the one-year multi-phase extraction project was significantly effective, with removal rates of pollutants in heavily contaminated areas reaching 64.56% to 99.26% at varying depths. A high degree of homogeneity and spatial autocorrelation was maintained among NAPLs prior to extraction, with correlation coefficients ranging from 0.26 to 0.72. The extraction process influenced the distribution and concentration of pollutants, resulting in changes in the correlations among them. The content and depth of DNAPLs in the site maintained a significant positive correlation, while LNAPLs exhibited a negative correlation. Under the extraction influence, the spatial distribution fitting of pollutants showed a substantial reduction in the central area and surrounding contamination halo, with the range of 1,4-dichlorobenzene pollution experiencing the largest decline, reducing the contaminated area by 91.98%. The assessment indicated that the proportion of high ecological risk points within the site significantly decreased post-extraction, and the multi-phase extraction comprehensively reduced the ecological risk of the site. However, some points of medium to high ecological risk still exist (primarily related to total petroleum hydrocarbon pollutants), which should be monitored and addressed in future remediation efforts.

Based on the InVEST model, Hierarchy of Needs Theory, and ecosystem service supply-demand analysis, we utilized Linkage Mapper and other tools to extract ecological sources, corridors, and pinch points in the Sichuan Basin from 2005 to 2020, following the least-cost path theory. The ecosystem service supply-demand relationship was analyzed to construct the ecological security pattern of the basin. Spatially, ecosystem service supply and demand in the Sichuan Basin exhibited a negative correlation. Despite an overall ecological surplus (supply exceeding demand), spatial mismatches between supply and demand intensified regional contradictions. From 2005 to 2020, the area of ecological sources in the basin was 68700km², 63900km², 63100km², and 64800km², respectively, presenting a “dense periphery-sparse center” ring-shaped distribution. The total length of ecological corridors across four periods increased continuously (6693.38km, 8342.29km, 8594.62km, and 14130.94km), forming a “periphery-connected, sparse-center, dense-east” network structure. Ecological pinch points were clustered at source junctions, while obstacle points were concentrated near fragmented source patches, particularly in the eastern parallel ridge-valley region. Integrating ecosystem service supply-demand dynamics and existing ecological security patterns, we proposed an optimized protection framework termed “Three Belts, Four Zones, and Five Cores”. Three Belts: East-west axial belts in the basin’s southern and northern regions, and a north-south axial belt in the eastern basin. Four Zones: Ecological security protection zone (eastern Sichuan), ecological restoration zones (western and northern Sichuan), and an ecological fragility recovery zone (central Sichuan). Five Cores: Key connectivity nodes in the southern basin and the eastern parallel ridge-valley area.

To elucidate the interaction mechanisms between iron-manganese minerals and antibiotics/antibiotic resistance genes (ARGs), enhance the understanding of their environmental degradation behaviors, and advance remediation technologies, this study systematically investigates the multifaceted degradation mechanisms of antibiotics by iron-manganese minerals. The mechanisms are explored through the following pathways: synergistic catalysis through surface Brønsted acid sites, Lewis acid sites, and hydroxyl groups promoting antibiotic hydrolysis; semiconductor-mediated photocatalytic degradation via electron-hole pair generation; direct oxidation by redox-active components such as Fe(III)/Mn(IV) coupled with activation of persulfate/hydrogen peroxide to yield reactive species for complete mineralization; concomitant radical-induced damage to ARGs through phosphodiester bond cleavage and base pair destruction, effectively inhibiting their horizontal transfer and evolution. The practical efficacy of iron-manganese minerals has been demonstrated in diverse environmental matrices including soils, aquatic systems, sludge, and livestock manure, with degradation efficiency dynamically regulated by pH, organic matter content, co-existing ions, and moisture conditions. Future research should prioritize establishing integrated databases mapping antibiotic-ARG co-degradation pathways and toxicity profiles, developing in situ dynamic characterization techniques for mineral interface reactions, engineering environment-adaptive mineral- based composite materials.

Soil contamination with phthalate esters (PAEs) is a worldwide environmental issue, and a stable and efficient functional microbial agent could be applied to achieve synergistic PAEs degradation. The review comprehensively compared various methods and pathways of microbial immobilization. The different factors on PAEs elimination such as mass transfer environment, substrate concentration, immobilization conditions, and strain combinations were demonstrated. The metabolic pathways of PAEs driven by enzymatic reactions of functional microbes were elucidated. The biological mechanisms of synergistic degradation of PAEs by microbial communities were clarified, and crucial future research areas may include the construction of microbial composite communities, optimization of immobilization carriers, and creation of microbial agent products. Compared to single-free bacteria, the immobilized PAEs-degrading microbial agents not only resist the interference of complex external environments, but specifically perform well on PAE degradation. In addition, immobilized microbial agents may positively promote crop growth.

This review summarizes the synthesis and regulation mechanisms of quorum sensing (QS) systems in Gram-negative and Gram-positive bacteria, focusing on key signalling molecules including acyl-homoserine lactones (AHLs), autoinducing peptides (AIPs), and autoinducer-2 (AI-2), as well as their applications in environmental remediation. The results demonstrate that QS-mediated regulation of bacterial collective behaviors primarily involves two critical processes: synthesis/release of signalling molecules and subsequent recognition-triggered behavioral responses. Notably, S-adenosylmethionine (SAM) serves as a common substrate for multiple QS signal biosynthesis pathways, potentially reflecting co-evolutionary adaptation between QS systems and bacterial coordination. Certain signalling molecules exhibit cross-kingdom functionality, not only adjusting conspecific bacterial behaviors but also mediating communication between phylogenetically unrelated bacteria and plants. Microbial communities leverage QS to synchronize population-level activities, optimize community architecture, and modulate synthesis of key degradation enzymes, thereby enhancing biofilm-mediated remediation efficiency. Finally, the development directions of QS-based microbial remediation technologies are discussed. The research results provide theoretical foundations and practical insights for studies on microbial remediation technologies.

To address the co-contamination of phthalic acid esters (PAEs) and cadmium (Cd) in agricultural soils of Guangxi province, a novel approach using immobilized functional microbial agent has been proposed. A composite microbial consortium, composed of three functional bacterial strains including Gordonia sp., Rhodococcus sp., and Bacillus sp., was developed with the ability to tolerate Cd and degrade PAEs. The microbial agent was immobilized on a thiol-modified montmorillonite-biochar composite carrier with optimized preparation conditions to enhance their remediation capabilities. The synergistic remediation efficacy of the agent on PAEs-Cd co-contaminated soils and the underlying mechanisms were elucidated. The results demonstrated that the composite microbial consortium achieved a degradation rate of 92.7% for total PAEs within 5days, while the carrier material exhibited a Cd saturation adsorption capacity of 15.2mg/kg. The optimal immobilization conditions were determined to be 30℃, with a bacteria-to-carrier ratio of 1:20 (V/M) for 1day. Under these conditions, the immobilized microbial agent achieved a degradation rate of 95.4% for ΣPAEs within 5days. When applied at a dosage of 1% to PAEs-Cd co-contaminated soils, the immobilized microbial agent resulted in 54.14% PAEs elimination and 37.06% decrease of exchangeable Cd after 50days. The immobilized microbial agent exhibited favorable synergistic remediation efficacy for PAEs-Cd co-contamination. The research findings provided a theoretical basis for the remediation of PAEs-Cd co-contamination in farmland soil of Guangxi and filled the theoretical gap in the control and remediation of PAEs-Cd co-contamination.

To investigate the effect of the Fenton-oxidized composting process on the removal of estrogens in manure, this study determined the concentrations of four estrogens—estradiol (E3), 17β-estradiol (17β-E2), bisphenol A (BPA), and ethinylestradiol (EE2)—in cow manure at various time points (0, 3, 12, 24, 48, 96, 192, 384, and 768hours) using the Fenton-oxidized composting process. The influence of Fenton's reagent and citric acid on estrogen removal during Fenton oxidation were also examined. Results demonstrated that after 3hours of treatment with Fenton's reagent and citric acid, the residual rates of E3, 17β-E2, BPA, and EE2in cow dung were 15.10%, 2.65%, 9.90%, and 11.44%, respectively, which were significantly lower than those observed in the non-oxidizing reagent treatment group. Following 32days of composting, the residual concentrations of E3, 17β-E2, and BPA fell below detectable limits, while the residual rate of EE2was only 2%. Additionally, seed germination rate analysis during the oxidized composting process revealed that the seed germination index of Brassica chinensis exceeded 50%, indicating that the composting products exhibited no apparent toxic effects on vegetable seeds. Consequently, the Fenton-oxidized composting technology can effectively accelerate the removal of estrogens from livestock manure, thereby facilitating its resourceful and harmless utilization.

The transmission of prions can induce the largely spread of transmissible spongiform encephalopathies, which pose a serious threat to animal and human health. Soil is a natural reservoir for prions. Prions can enter the soil through animal excretion, carcass decomposition, and bind to soil components. The binding of prions to different soil components varies significantly, and their effects are simultaneous and mutual, jointly influencing the spread of prions in the soil. On the one hand, the adsorption of soil particles and humic substances enhances their stability and persistence in the soil, reduces their bioavailability, and thus inhibits the spread of prions. On the other hand, montmorillonite and manganese ions can increase their activity and infectivity to a certain extent, thereby contributing to the spread of prions. The control of prions in the soil can be achieved through biotechnologies such as environmental prevention and control, enzyme treatment and composting technique, based on the improvement of their detection methods. In the future, the research on prions in the soil environment should take more into account the influence of the characteristics of soil compounds and native microorganisms on prions, so as to promote the development of in-situ prion degradation methods to control their spread. This work will provide theoretical support for the development of new technologies for soil prions control.

To systematically assess the environmental risks of natural steroidal estrogens in vegetables, there is an urgent need to establish an efficient, reliable, universal, and convenient extraction and detection system for these estrogens. This study demonstrated that the three natural steroidal estrogens showed a strong linear relationship, with a correlation coefficient greater than 0.9995. The detection limits for estradiol, 17β-estradiol, and estrone were found to be 0.36~3.23μg/kg, 0.76~3.67μg/kg, and 13.97~20.12μg/kg, respectively. The average recoveries for these substances ranged from 104.9% to 130.5%, while the relative standard deviations were between 4.9% and 18.7%. In root samples, the average recoveries were between 80.5% and 129.9%, with relative standard deviations ranging from 4.2% to 38.8%. This method detected natural estrogens in vegetable samples randomly collected in Nanjing city. The results indicated that natural estriol was detected in all vegetable samples, with a 100% detection rate in both the ground and root parts. The detection rate for 17β-estradiol was 75% in the ground part and 100% in the root. In contrast, the detection rate for estrone was 43.8% in the ground part and 18.8% in the root. Further studies are needed to assess the potential risks associated with estrone. Overall, The method exhibits high accuracy and precision, fulfilling the requirements for analysis and determination. Consequently, it provides scientific evidences for effectively assessing and control the environmental risks associated with natural steroidal estrogens in vegetables.

This review systematically explores the application of machine learning technology in the field of microplastics, covering classification and identification, quantitative analysis, and prediction of adsorption properties. By combing through recent literature, it has been found that technologies such as convolutional neural networks (CNN) and support vector machines (SVM) are of great significance for improving the accuracy and efficiency of microplastic detection. In classification and identification, CNN models can accurately distinguish the types and shapes of microplastics; during quantitative analysis, machine learning can quickly determine the concentration of microplastics with the help of image and spectral data. In terms of predicting adsorption properties, models based on quantitative structure-property relationships (QSPR) have shown higher accuracy and robustness than traditional models. However, there are currently challenges such as poor data quality, difficulties in collection and annotation, and a lack of model interpretability. Future research should focus on diversifying datasets and enhancing model interpretability to promote the further application of machine learning technology in microplastic research.

The scientific prevention and effective control of environmental health risks are essential to achieving the vision of a‘Beautiful China’. However, China currently lacks comprehensive guidelines for medium and long-term environmental health risk management. This study discusses the ideal levels of environmental health risk management required to meet key milestones of a‘Beautiful China. Through the review of previous management efforts, we identify several critical challenges: insufficient risk prevention and control system, inadequate regulatory standards for conventional pollutants, and limited research base and understanding of emerging pollutants. In the end, this study concludes by proposing a future management system that prioritizes public health protection through systematic prevention and control of both conventional pollutants and emerging pollutants.

Human lung cancer cell A549were used as the test cell. Three kinds of organophosphorus flame retardants, i.e., tris(2-butoxyethyl) phosphate (TBOEP), tris(1-chloro-2-propyl)phosphate (TCIPP), and tri(4-isopropylphenyl)phosphate (IPPP), were selected as representative compounds, which are frequently detected in the environment. The toxic effects of the three compounds on A549cell were studied through multiple toxicity test endpoints. Results showed that the three OPFRs could inhibit cell viability, stimulate the production of excessive reactive oxygen species and reduce the mitochondrial membrane potential in cell, induce cell inflammation and cause DNA damage. All the cytotoxicity indicators were dose-dependent. OPFRs with low concentrations had less effect, and the toxic effect enhanced with the increase of OPFRs concentrations. Compared with the three OPFRs, their toxic effects on A549cells ranked as TBOEP > TCIPP ≈ IPPP. Especially, when the cells were exposed to TBOEP with a high concentration of 500 μmol/L, the cell viability was less than 5%, the amount of reactive oxygen species in cell increased by three times, the mitochondrial membrane potential decreased by 46.5%, the secretion of inflammatory factors IL-6 and TNF-α increased by 124.4% and 262.7%, and the content of DNA damage markers increased significantly.

To investigate the environmental behavior of organophosphate esters (OPEs) in the surroundings of the electronics industry, an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to determine the concentration levels of 18 OPEs in soil, atmospheric, and wastewater samples, which were collected from surrounding areas of typical electronic industry enterprises in Shenzhen. Correlation analysis and principal component analysis (PCA) were applied to identify pollution sources, and the health risk levels of people of different age groups were evaluated. The results indicated that the detection rates of 18 OPEs in various environmental media were found to range between 40.9% and 100.0%. In 34 soil samples, 21 atmospheric samples, and 30 wastewater samples, the mean concentrations of ∑18 OPEs were determined to be 283ng/g (12.2~857ng/g), 4.48×10⁵ pg/m³(3.12×10³~2.95×10⁶ pg/m³), and 1.11×10⁶ ng/L (5.39×10⁵~2.73×10⁶ ng/L), respectively. Tris(2,4-di-tert-butylphenyl)phosphate (AO168=O), tris(4-tert-butylphenyl) phosphate (T4tBPP), tris(2-chloropropyl) phosphate (TCPP), and bisphenol A bis(diphenyl phosphate) (BPADP) were identified as the predominant OPEs across all media. The correlation and principal component analysis (PCA) results demonstrated that OPE contamination in the vicinity of electronic industry enterprises was predominantly influenced by industrial production emissions and traffic-related discharges. Non-carcinogenic and carcinogenic health risks associated with multi-pathway exposure to OPEs in soil and atmospheric media across different age groups were found to remain within acceptable thresholds; however, the health risks posed by long-term cumulative OPE exposure were identified as requiring sustained scientific attention.

This paper used the multi-region input-output model to calculate the embodied carbon and its industrial structure of China's inter-city industrial trade based on the perspective of value-added trade, depict the structural characteristics of the embodied carbon transfer network, and the mechanism of the embodied carbon transfer network is revealed through the exponential random graph model (ERGM). The study found that: The inter-city industrial trade embodied carbon transfer network is dense but without scale, with small world structure and miscompatibility. Resource-intensive and capital-intensive industries contribute more than 90% of the embodied carbon transfer. Cities with high embodied carbon net outflow are mainly resource-based and industrial cities in the Yellow River Basin and the Bohai Rim region, while cities with high embodied carbon net inflow are mainly the national and regional central cities east of Hu Huanyong Line. Large-scale embodied carbon transfer mainly occurs among the cities within the provinces, and the inter-city embodied carbon transfer network has a certain provincial boundary effect. The embodied carbon transfer of provincial cities presents the "core-edge" structure around the provincial central cities. The embodied carbon transfer of inter-provincial cities shows the radial structure from the resource-based cities and industrial cities in the Yellow River basin and the Bohai Rim region to Beijing, Shanghai, Hangzhou, Ningbo, Suzhou, Chongqing, Guangzhou, Guangzhou and Shenzhen and other central cities. In the mechanism of inter-city embodied carbon transfer network, mutualism and preference dependence effect are important endogenous mechanisms. Cities with developed economy, dense population, high per capita consumption level and advanced industry are more inclined to flow into the embodied carbon. Cities with higher comparative advantages and low energy efficiency in resource-based industries are more inclined to outflow embodied carbon. Policy proximity and geographic proximity have a positive impact on the inter-city embodied carbon transfer network, and technical proximity has a negative impact.

This study analyzed the carbon reduction effect of national green data centers on cities and its mechanism. Then, based on the pilot and construction work of national green data centers, a quasi-natural experiment was constructed. Using the difference-in-differences method and panel data of 283 cities from 2011 to 2022, the carbon reduction effect of national green data centers was empirically analyzed, and its mechanism and heterogeneity were explored. The pilot of national green data centers has a significant carbon reduction effect, with a coefficient of -0.013, which is significant at the 5% statistical level. The pilot of national green data centers significantly reduces the carbon emission intensity of cities. This result remains valid after multiple robustness tests, including parallel trend tests, placebo tests, exclusion of selection bias, exclusion of the impact of other policies, and exclusion of the impact of the epidemic. The pilot of national green data centers can reduce the carbon emission intensity of cities by promoting the development level of the digital industry and the green technological innovation level of the region. The impact of the pilot of national green data centers on the development level of the digital industry and the green technological innovation level is significantly positive at the 1% statistical level, with coefficients of 0.039 and 0.061, respectively. The carbon reduction effect of national green data centers is more significant in non-energy-rich cities, cities with high environmental protection levels, and cities with high information levels. The impact of the pilot of national green data centers on these three types of cities is significantly at least at the 10% statistical level, with coefficients of -0.016, -0.017, and -0.016, respectively. Therefore, efforts should be made to promote the green transformation of data centers and expand the scope of the pilot of national green data centers.

This article constructed a multidimensional urban sprawl measurement index system from the structural dimension, morphological dimension, density dimension, and efficiency dimension. Based on map visualization, standard deviation ellipse, and cold and hot spot analysis, it explored the spatiotemporal characteristics and migration evolution patterns of China's urban comprehensive sprawl from 2005 to 2020. The spatiotemporal geographically weighted model (GTWR) was used to empirically examine the spatiotemporal heterogeneity of the impact of multidimensional urban sprawl on carbon emission intensity. Research shows that: (1) The comprehensive urban sprawl in China exhibited a spatial difference of "high in the east and low in the west", but the urban sprawl in the eastern coastal and northeastern regions has declined in the later stage of the sample. The standard deviation ellipse shows a trend of centripetal clustering, and the center of gravity of the distribution shifts towards the southwest as a whole. The analysis of hot and cold spots presents regional differences of "hot in the east and cold in the west". (2) The overall urban sprawl has a significant impact on carbon emissions, and over time, it plays a positive promoting role in an increasing number of cities. The positive promotion area is mainly concentrated in the central and western regions and coastal areas, while the negative inhibition area is mainly the North China Plain and the Pearl River Delta. (3) There is significant spatiotemporal heterogeneity in the influencing factors of each dimension. In terms of temporal trends, the structural dimension promotes carbon emissions in most cities and its influence increases year by year; The form dimension has shifted from a promoting effect to a inhibiting effect on carbon emissions in most cities; The density dimension and efficiency dimension suppress carbon emissions in most cities, but the density dimension shows a polarization trend year by year, while the influence of the efficiency dimension weakens overall. In terms of spatial distribution, the influence of structural dimension and density dimension is stronger in the southeastern, western, and northeastern regions, while the significant effect of morphological dimension is in the northeastern border and central western regions, and the significant effect of efficiency dimension is in the central and western regions.

Based on the super-efficiency SBM model to measure the carbon emission efficiency (CEE) of China's chemical industry across 30 provinces from 2007 to 2021, this study employs spatial analysis methods and kernel density estimation to characterize the spatiotemporal evolution patterns of CEE at both the national and regional levels. Furthermore, a Tobit regression model is applied to identify its influencing factors. Although the CEE of China's chemical industry exhibited a fluctuating upward trend during the study period, the overall level remained relatively low, with a mean value of 0.629. Moreover, a persistent regional disparity was observed, following the order of eastern China (0.750) > western China (0.584) > central China (0.530). The spatial distribution of CEE ultimately displayed a "southwest-northeast" orientation, with significant shifts in spatial patterns gradually forming a "tripartite balance" structure, though most regions remained at low efficiency levels. Additionally, the mean Gini coefficient was 0.322, indicating substantial spatial heterogeneity overall. The CEE in eastern China surpassed that of the central and western regions, with hypervariable density identified as the primary source of regional disparities. The overall evolutionary trend of CEE in the chemical industry was positive, with interprovincial gaps gradually narrowing. While the trends in eastern, central, and western China were generally favorable, attention should be paid to the increasing divergence in the western region. Industrial agglomeration, energy structure, and economic development level significantly promoted CEE, with the energy structure of the chemical industry having the strongest impact which coefficient is 0.9942. Therefore, the government should prioritize optimizing the energy structure of the chemical industry while fully leveraging the positive effects of industrial agglomeration and regional economic development. Additionally, enhancing interregional collaboration and formulating region-specific policies are crucial for further improving the CEE of the chemical industry.

This study establishes a carbon emission reduction measurement model for the secondary ash recycled ceramsite project from the perspective of carbon footprint, combined with the National Certified Voluntary Emission Reduction (CCER) methodology. Taking the 40000 tons/year secondary ash recycled ceramsite project as an example, empirical analysis is conducted to evaluate the project's carbon emission reduction. Based on the analysis of key carbon emission factors, the carbon emission reduction potential of the secondary ash recycled ceramsite project is optimized and evaluated. The results show that the total CO₂e emission reduction of the 40000 tons/year secondary ash slag regenerated ceramsite project in 2023 is 32600 tons, of which the ceramsite production stage contributes to 95% of the emission reduction. From the perspective of carbon footprint analysis, the total annual CO₂e emissions of the project are about 64900 tons, and the processing, production, and raw material acquisition stages are key links in the carbon emissions of the ceramsite project. From the analysis of CO₂ emission source categories, the substitution of solid waste materials such as secondary ash and sludge is the key to carbon reduction in the ceramsite industry. In addition, the priority order of adding solid waste materials is secondary ash, sludge, and waste soil. Regarding the optimization of carbon emission reduction potential, under four low-carbon scenarios of green raw materials, clean power grid, low-carbon transportation, and recycling, the secondary ash regenerated ceramsite project achieved CO₂e emission reductions of 69300, 34200, 35600 and 32800 tons, respectively. Under the green raw material scenario, the ceramsite industry has a carbon emission reduction potential of 9million tons.

This study centers on environmental regulatory policies, employing a two-way fixed effect model to scrutinize their impact, underlying mechanisms, and theoretical implications on new quality productivity enhancement. A U-shaped correlation exists between environmental regulations and the enhancement of new quality productivity. Beyond a critical turning point, a 1% escalation in vertical environmental regulation intensity correlates with a 124.42% augmentation in high-quality economic development. Environmental regulations significantly bolster the advancement of new quality productivity levels in both eastern and western provinces of China. Environmental regulations serve as a catalyst in amplifying the mechanisms fostering new quality productivity, particularly by influencing the "new labor tools" and "new infrastructure" subsystems.

To address the problems of traditional methods lacking the characterization and assessment of internal environmental risks in chemical industrial parks, having single assessment indicators, and not considering the factor of risk prevention and control capabilities, a refined assessment method for sudden environmental incidents at the scale of chemical industrial parks was proposed based on the grid-based risk analysis method for sudden environmental incidents in administrative regions. This method refines the risk unit grid, optimizes the environmental risk field intensity model, improves the vulnerability standards for environmental risk receptors, and introduces a correction factor representing the level of environmental risk prevention and control. Taking a certain fine chemical industrial park along the Yangtze River in Jiangsu Province as an example, environmental risk assessments were conducted and compared using the original assessment method and the refined assessment method. Compared with the original assessment method, the refined assessment method better characterized the distribution of atmospheric and water environmental risks within the park. The number of people involved in the high-risk and medium-risk areas of the atmospheric environment in the study area increased by 17,000, and the areas of high-risk and high-medium-risk areas of the water environment increased by 0.91% and 9.45% respectively. This method can effectively establish the connection between environmental risk assessments at different scales such as chemical industrial parks and environmental risk enterprises, more accurately identify high-risk enterprise units and environmental receptors, and ensure the safety of the internal population and key water bodies in the park.