To investigate the causes of sludge bulking during high load operation of activated sludge and the control effect of adding vanillin, this study examined the overall changes in microbial community, filamentous bacteria genus, extracellular polymeric substance secreting bacteria genus, and functional gene clusters involved in exopolysaccharides synthesis when operating under conventional load or high load with or without vanillin addition. The results indicated that after sludge bulking occurred, there was a decrease in the proportion of proteins to polysaccharides in extracellular polymeric substances. This reduction limited the ability of proteins to act as a biological flocculant and resulted in poorer settling performance of the sludge. The causes of sludge bulking during high load operation were attributed to filamentous bacteria dominated by Sphaerotilus and viscous bulking led by Flavobacterium. The addition of vanillin effectively inhibited the proliferation of Sphaerotilus but still allowed for viscous bulking dominated by Thauera and Zoogloea. Metagenomic sequencing analysis revealed that the abundance of alg, eps, and pel functional gene clusters involved in exopolysaccharide synthesis increased by 0.4~0.5 times, 0.8~1.1 times, and 10.3~15.7 times, respectively. These findings suggest that these gene clusters may be potential factors contributing to the substantial increase in exopolysaccharide content observed in bulking sludge.

To investigate the spatio-temporal variations, influential factors and environmental health effects of negative air ions (NAIs) in Hainan tropical rainforests, a mobile comprehensive measurement platform was utilized to carry out field observation during typical tourist season (January), four types of typical forest stands (evergreen broad-leaved, deciduous broad-leaved, coniferous and bamboo forests) at eleven different altitudes in the Wuzhishan area of the Hainan Tropical Rainforest National Park were measured. The concentrations, spatiotemporal variations of NAIs, and their relationships with forest types, meteorological factors, air quality, and volatile organic compounds (VOCs) were analyzed. A comprehensive evaluation method for the ecological health function of tropical rainforest based on the Forest Health Index (FHI) was established. The results showed that the NAI concentration in the Wuzhishan area was relatively high (3541±882) moles/cm³, reaching Level VI of the World Health Organization's air freshness classification standard. The NAI concentration was increased with altitude initially and then decreased. Coniferous forest was found to have the highest NAI concentration, followed by broad-leaved forest, with bamboo forest having the lowest. A total of 66VOCs were detected, with sesquiterpenes and oxygenated organic compounds accounting for over 80%. NAIs were shown significant positive correlations with relative humidity, fine particulate matter, and monoterpenes, and significant negative correlations with sesquiterpenes and aromatic hydrocarbons. The FHI in the afternoon was generally found to be higher than that in the morning, with most sampling sites reaching Level II or above.

This paper employed the multi-regional input-output (MRIO) to clarify the spatial and temporal evolution of the embodied pollutant emission patterns in China's interprovincial trade in 2012, 2015, and 2017. The structural decomposition analysis (SDA) model was applied to identify the socio-economic factors affecting the changes in pollutant emissions. The results showed that the areas with net pollutant export gradually shifted from those which have developed economic on the east coast to those have rich resources in the northwest. Moreover, the gap between provinces in net imports and exports of pollutants decreased. For example, the gap in SO₂ from 2012 to 2017 reduced by 63%. In addition, the increase of final demand was the main driver of the increase of emissions, with an average contribution of up to 669% to the emissions of the four air pollutants. The optimization of the energy consumption structure and the reduction of energy consumption per unit of GDP effectively curbed the momentum of emissions increase. The average contribution of the energy consumption structure to the four pollutants decreased from -220.75% to -546.25%. Although the impact of production technologies is minor, its impact on emissions has shifted from a facilitating to a dampening effect. This study provides new insights for improving energy efficiency and developing a clean energy mix, which contributes to developing measures to mitigate demand-side pollutant emissions and coordinated regional trade policies.

In Momoge Nature Reserve, three distinct water bodies were selected for the investigation of the composition, spectral characteristics, and sources of dissolved organic matter (DOM) utilizing three-dimensional excitation emission matrix spectroscopy in conjunction with parallel factor analysis (PARAFAC). Additionally, two-dimensional correlation spectroscopy combined with structural equation modeling was employed to analyze the variations of DOM components and their relationships with water quality parameters. The results indicated that the DOM in the water bodies originated from both endogenous and exogenous sources, which has obvious humification characteristics. Five components were identified as microbial metabolites (C1), fulvic acid-like (C2 and C4), humic acid-like (C3) and tryptophan-like (C5) through three-dimensional fluorescence coupled with PARAFAC. Of five components, C1content was the highest (41.37%). The changing sequence of DOM components along the direction of water flow was characterized by 2D-COS as follows: C4→C2→C3→C1→C5, with humic-like substances showing greater variation than tryptophan-like substances, and the content of tryptophan-like substances being relatively stable. The humification degree of DOM directly affected the water quality status with influence weight of 46.17%. The water quality was indirectly impacted by DOM components C2 and C3 with a 17.59% influence weight. Insight into the response mechanism of DOM properties to water quality in Momoge Nature Reserve could provide a theoretical basis for the ecological protection of nature reserves.

Corn straw biochar (Y-BC) was prepared by high-temperature pyrolysis method and its structure and morphology properties were characterized with a series of analytical techniques. The effects of initial pH and co-existing ions on tetracycline (TC) removal by Y-BC activated two types of persulfates: peroxydisulfate (PDS) and peroxymonosulfate (PMS) were systematically compared. The results showed that Y-BC activated PDS system could effectively remove TC under acidic and neutral conditions (pH=3~7), and TC removal efficiency was between 69.0% to 75.7% in 60min, while alkaline conditions (pH=9~11) TC removal efficiency reduced to 47.8%~48.4%. In contrast, the Y-BC-activated PMS system demonstrated a broad pH range for TC removal, and TC removal efficiency stabilized at 80.9%~86.8% at initial pH 3~11. The Cl^- and NO₃^- anions exhibited negligible effects on both activated persulfate systems. Meanwhile, HCO₃^- showed an inhibitory effect on TC removal by the Y-BC-activated PDS system while promoting the effect by the Y-BC-activated PMS system. TC removal efficiency decreased by 7.6% and increased by 5.1% with Y-BC-activated PDS and PMS, respectively. Combined the results of X-ray photoelectron spectroscopy, quenching experiments, and electron paramagnetic resonance analysis, it was deduced that the primary active sites for Y-BC activated PDS system were defect structures, and TC degradation was mainly through singlet oxygen (¹O₂) generation and electron transfer mechanisms. Conversely, functional groups served as key active sites for the Y-BC-activated PMS system, and TC degradation was primarily via hydroxyl radical (·OH) formation.

This study examines the impact of cultural and tourism integration on green total factor productivity in China, utilizing provincial panel data from 2010 to 2021 and employing both static panel models and system GMM models. The findings reveal a nonlinear "U-shaped" relationship, where culture and tourism integration initially suppresses but ultimately enhances green total factor productivity, contingent upon achieving a preliminary level of coordination. Regional analysis shows that this "U-shaped"relationship is present only in the highly integrated eastern regions. Additionally, market environment and industrial agglomeration significantly moderate the relationship between culture and tourism integration and green total factor productivity. The advanced industrial structure emerges as the ultimate pathway through which culture and tourism integration fosters improvements in green total factor productivity. Based on these insights, targeted recommendations are proposed to promote culture and tourism integration, thereby empowering green total factor productivity.

The active manganese oxide (MnO_x) filter media was found to exhibit efficient catalytic oxidation performance in removing ammonia nitrogen and manganese pollutants from water, but it was lacking in stability for the removal of bisphenol A(BPA), and the interaction mechanism with other inorganic pollutants remained unclear. In this study, sodium persulfate (NPS) was used to enhance the effect of the activated filter material (FM) on the removal of BPA. The experiment revealed that the removal rate could be increased to over 80% with the addition of just 0.1mmol/L of NPS, and the removal efficiency was further improved as the NPS concentration increased, ultimately reaching 100%. The addition of NH₄⁺ and Mn²⁺ was found to increase the production of reactive species by promoting electron transfer and providing electrons, respectively, thus enhancing the removal efficiency of BPA. The cycling experiment demonstrated that, while the FM exhibited good stability, the removal rate dropped to 48% after 11consecutive uses; however, this rate could be maintained above 65% with the addition of NPS. Free radical quenching and EPR experiments, along with X-ray photoelectron spectroscopy (XPS) analysis, confirmed that the primary reactive species in the filter material/NPS system were SO₄^·−, ·OH, and ¹O₂, with Mn(III) playing a crucial role in the catalytic oxidation process for removing BPA. The addition of NPS facilitated the formation of Mn(III), thereby promoting the removal of BPA.

Water pollution incidents were collected, and the characteristics of the incidents and their impact on population health were summarized. The types of water pollution incidents were classified as industrial pollution, agricultural pollution, and urban pollution. Industrial pollution were primarily caused by anthropogenic emissions and contaminant leakage. The pollutants were primarily heavy metals and chemicals. These pollutants were not usually directly affecting human health but resulted in the most economic losses once they occurred. Agricultural pollution, encompassing arable land pollution and animal husbandry pollution, was leading to economic losses with no serious health damage being caused. Urban pollution was being closely related to human health, and the health consequences caused by microbial pollution were the most frequent, primarily acute damage. The physiological and psychological health of the population were affected after the occurrence of the pollution incidents. Limited research had been conducted on residual water pollution and its chronic long-term effects on public health. The health risk assessment of residual pollution was worth being explored.

Using carboxymethyl chitosan (CMCS) and carboxymethyl cellulose (CMC) as stabilizers, two sulfidated nano zero-valent iron (S-nZVI) composite materials were synthesized in one-step. The apparent morphology, functional group composition, and surface chemical properties of the materials were characterized using SEM-EDS, FTIR, and XPS. Static adsorption experiments were conducted to analyze the removal performance and mechanisms of Cr(VI) and trichloroethylene (TCE) by the two S-nZVI materials. Furthermore, the resistance of the optimal material to interference from groundwater pH and coexisting anions was evaluated. The results showed that CMCS and CMC surfaces contained various functional groups that could form covalent bonds with S-nZVI, improving the dispersion of the sulfidated nano zerovalent iron particles. The adsorption kinetics of Cr(VI) and the degradation kinetics of TCE by the two S-nZVI composite materials were described by pseudo-second-order kinetic models and pseudo-first-order kinetic models, respectively. The isothermal adsorption process of Cr(Ⅵ) removal by the two S-nZVI composite materials was capable of being simulated by the Langmuir model. Moreover, the S-nZVI composite material stabilized with CMCS (CMCS-S-nZVI) presented the highest maximum adsorption capacity for Cr(Ⅵ), whic h was recorded as 79.46mg/g. The removal efficiency of Cr(VI) and TCE by CMCS-S-nZVI was not significantly affected by pH in the range of 6~9 or by the presence of NO₃^- and SO₄^2-. During engineering applications, the possible negative effects of Cl^- should be paid special attention to. These findings provide theoretical guidance for the effective implementation of permeable reactive barrier (PRB) technology to remediate groundwater contaminated by chlorinated hydrocarbons and heavy metals.

Based on data from 45 soil cores, 35 lake sediment cores, and 32 sea sediment cores in China, this study found a type of ^239+240Pu peakless distribution cores in soil, lakes, and marine environments, and discussed their causes of ^239+240Pu peakless distribution. The results show that there were two main types of peakless distribution of ^239+240Pu in soil core samples: one that the ^239+240Pu specific activity increased with depth, and the other that the ^239+240Pu specific activity decreased with depth; when using a Convection Dispersion Equation (CDE) model to simulate the migration behavior of ^239+240Pu in soil cores, the apparent convection rate showed a positive correlation with the ^239+240Pu maximum depth (n=45, R²=0.847). There was only one type of peakless distribution of ^239+240Pu in lake and ocean core samples: the ^239+240Pu specific activity decreased with depth. Meanwhile, the sedimentation rate of lake core samples (n=35, R²=0.921) or the maximum apparent convection rate of marine core samples (n=32,R²=0.949) also showed a positive correlation with the ^239+240Pu maximum depth. The maximum apparent convection rate of the exchangeable ^239+240Pu in the peakless distribution core sample was close to the sedimentation rate, and the maximum apparent convection rate didn’t affect the vertical distribution of ^239+240Pu in the core sample.