Cover illustration
(See: Yang Gao, Xiuwen Guo, Wenbin Kou, Xiaojie Guo, Shaoqing Zhang, Huiwang Gao, Deliang Chen, 2025, 19(7): 100)<br>
Under global warming, extreme weather and air pollution pose severe risks to health, economies, and societal stability, with their interactions amplifying impacts. Traditional
[Detail] ... Download cover Download table of contentsUnder global warming, extreme weather events and air pollution are becoming increasingly critical challenges. Both pose serious risks to human health, economies, and societal stability, and their complex interactions can further amplify these impacts. Numerical models are essential tools for studying these phenomena; however, traditional low-resolution Earth system models often fail to accurately capture the dynamics of extreme weather and air pollution. This limitation hinders our mechanistic understanding, reduces the reliability of future projections, and constrains the development of effective adaptation strategies. Dynamical downscaling—an approach that uses high-resolution regional models nested within global models—offers a partial solution. However, this method inherits biases from the parent global models and often fails to adequately represent multi-scale and cross-sphere interactions involving the atmosphere, land, and oceans. These shortcomings underscore the growing need for developing and applying high-resolution Earth system models that can more comprehensively and accurately depict land–sea–atmosphere interactions, including heat and material exchanges and their spatial heterogeneity. This article explores the current challenges, recent advances, and future opportunities in understanding the interplay between extreme weather events and air pollution, with a focus on the critical role of high-resolution modeling.
The identification of complete ammonia oxidizers (comammox) within the nitrite-oxidizing bacteria (NOB) genus Nitrospira, capable of oxidizing ammonia directly to nitrite and nitrate, represents a pivotal advancement in elucidating the microbial and metabolic pathways underlying nitrification in the global nitrogen cycle. Although comammox Nitrospira have been consistently identified across diverse environmental habitats, their rapid enrichment from complex activated sludge systems remains challenging owing to their intrinsically low growth rates and the restricted availability of cultured isolates. In this study, Candidatus Nitrospira inopinata (Ca. N. inopinata) was successfully enriched from anammox-inoculated sludge within 70 d under low ammonia concentrations (~4.88 mg/L), ambient temperatures (21.6–28.4 °C), and minimal aeration (0–0.01 mg/L), facilitated by the application of kanamycin (KAN). By employing 16S rRNA gene amplicon sequencing and quantitative polymerase chain reaction (qPCR) targeting the functional marker gene amoA, Ca. N. inopinata was identified as the dominant ammonia oxidizer, achieving a relative abundance of 95.22% in the nitrifying community. Kanamycin was shown to exert significant selective pressure, further enhancing the enrichment of Ca. N. inopinata. These findings demonstrate the feasibility of establishing comammox Nitrospira through direct inoculation of anammox pellets coupled with kanamycin, offering a robust and efficient strategy for rapid enrichment of comammox Nitrospira for biotechnological applications, while underscoring the energy-efficient advantages of comammox-driven ammonia oxidation processes.
The recovery of high-concentrations manganese (Mn) ion (tens of thousands of milligrams per liter) from hydrometallurgical tailing water poses considerable challenges, leading to resource wastage and environmental concerns. To address this, this study proposes the nucleation crystallization pelleting process, a technique that facilitates the adherence of Mn ion onto the surface of specialized seeds, enabling the formation of nucleation pellets for recovery. A multistage series reactor was used under optimized conditions (particle sizes of 60–80 mesh, sodium carbonate dosage of 2500 mg/L influent pH of 3, and upflow velocity of 50 m/h). A stable and continuous operation of the reactor resulted in a Mn ion removal rate of > 99%. Laser particle size analysis and scanning electron microscopy results revealed that seeds growth occurred progressively, forming a loose and porous surface structure that enhanced the attachment of manganese carbonate (MnCO3) particles. X-ray diffraction, X-ray photoelectron spectroscopy and zeta potential analyses results demonstrated that Mn ion predominantly adhered to seed surface in the form of MnCO3 with purity detection confirming nucleation pellets achieving a content of > 95%. This study demonstrates the high efficiency and practical applicability of this nucleation crystallization pelleting process and highlights its potential to significantly reduce resource wastage and environmental impacts, offering a practical and effective solution for recovering high-concentrated Mn ion from hydrometallurgical tailing water.
Lake Taihu, the largest shallow freshwater lake in eastern China, is a vital ecological and economic resource in the Yangtze River Delta. However, the region faces substantial environmental challenges from emerging contaminants (ECs), such as per- and polyfluoroalkyl substances (PFAS) and neonicotinoid insecticides (NEOs), driven by its dense industrial activities and aquaculture and agriculture sectors. A comprehensive literature analysis of the two ECs revealed that PFAS and NEOs have become recent hotspots both globally and in the Taihu Basin. The occurrence and distribution of PFAS and NEOs were summarized to show their high detection frequency and concentrations in the Taihu Basin. Risk assessment indicated that PFAS, NEOs, and other ECs posed considerable ecological risks within the Taihu Basin. Treatment techniques for PFAS and NEOs were systematically reviewed. However, many of these techniques face difficulties in scaling up in the Taihu Basin because of their strict conditions and high energy consumption. Ecological engineering treatment technologies are applied in the Taihu Basin to address emerging agricultural contaminants. Ecological engineering treatment technologies have limitations such as low removal efficiency and toxicity inhibition. Thus, it is necessary to develop more effective technologies for treating ECs in the Taihu Basin. A flowchart for identifying priority controlled ECs is presented and a future for the priority controlled emerging contaminants in the Taihu Basin is discussed. This study provides scientific insights for the sustainable control of ECs.
Cadmium (Cd) contamination poses a significant threat to the carbon fixation potential of farmland ecosystems, yet the molecular mechanisms underlying its inhibitory effects remain poorly understood. This study reveals that Cd competitively binds to ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), the key enzyme in photosynthetic carbon fixation, by displacing its native co-factor, magnesium (Mg). Both Cd2+ and Mg2+ bind to identical sites on Rubisco, forming a hexacoordinated complex with the oxygen atoms of ribulose-1,5-bisphosphate (RuBP) and key residues in Rubisco, including Asp203, His294, Glu204, and Lys201. While the binding affinity and stability of the Cd2+-Rubisco-RuBP complex are comparable to those of the Mg2+-Rubisco-RuBP complex, Cd2+ markedly shifts the catalytic activity of Rubisco from carboxylation to oxygenation. This shift results in the accumulation of 2-phosphoglycolate (2-PG), a photorespiration byproduct, by up to 11.57-fold. Consequently, the enhanced photorespiration pathway increases CO2 release, leading to a significant reduction in net CO2 fixation and ultimately inhibiting rice growth under hydroponic conditions. By elucidating the molecular mechanism through which Cd disrupts Rubisco’s dual catalytic activity, this study advances our understanding of how heavy metals impair carbon metabolism and carbon sequestration in plants, offering critical insights for mitigating Cd-induced carbon sink losses in cropland.
This study investigated the role of biochar in enhancing nitrogen removal efficiency (NRE) and stability in partial nitrification–anammox (PN/A) systems, focusing on its selective promotion of partial denitrification and maintaining the dynamic balance between AnAOB and denitrifying bacteria (DNB). The results showed that biochar enhances electron transfer, effectively reduced nitrate accumulation and significantly improved PN/A system NRE and stability. Under high ammonium conditions (800 mg/L), biochar increased NRE in the PN/A system to 83.58%, a 10% improvement over the anammox-control (ACK). Additionally, partial denitrification contributed 8% more to total nitrogen removal in the anammox-biochar (ABC) system. The porous structure and redox-active groups of biochar provided an ideal environment for key microorganisms, promoted microbial growth and increased specific anammox activity by approximately 1.25–1.46 times compared to ACK, further enhancing microbial stability under fluctuating nitrogen loads. Biochar also enriched AnAOB and DNB communities, sustained their dynamic balance and improved system stability by promoting nitrogen removal related gene expression. Overall, biochar demonstrated great potential for improving PN/A system efficiency, optimizing wastewater treatment, and reducing energy consumption and emissions.
In large cities, multi-source and multi-plant water supply, while effectively alleviating water shortage, poses notable challenges. In such systems, source switching alters dissolved organic matter (DOM) and microbial communities, whose interaction can destabilize water quality, cause pipe corrosion, form biofilms, and generate harmful by-products, thus threatening supply safety. However, the impact of DOM on microbial communities in water supply systems (WSS) has been less studied. To address this problem, EEM-PARAFAC, bioinformatics, and multivariate statistical analysis were used to get an in-depth understanding of the interaction between DOM and microbial communities. In this study, by analyzing the fluorescence index in the whole process, the DOM from source to tap showed weak humification and a strong autochthonous source. The flocculation process preferentially removed humus components. Moreover, water treatment processes (particularly chlorination) were found to significantly reduce microbial richness by 60.88% and alter community structure composition. Community assembly was largely explained by stochastic processes in subgroups. This stochasticity leads to diverse community structures under different environmental conditions, highlighting the complexity of microbial community formation. In water distribution network, microorganisms were the most stable (lowest AVD index, 0.029), followed by raw water (0.046) and the water treatment plant (0.065). The variations of fulvic-like acid and humic-like acid were considered the key components that need to be paid attention to in the whole process of WSS. This study provided insights into monitoring and managing multi-source multi-water plants WSS schemes.
Reducing H2S and CH4 emissions from wastewater is essential for environmental protection and public health. This study screened microbial strains capable of effectively reducing these emissions from anaerobic wastewater and explored their mechanisms. The results demonstrated that Bacillus subtilis and Saccharomyces cerevisiae reduced H2S emissions by 42.67% and 68.72%, and CH4 emissions by 58.17% and 77.12%, respectively. Both strains notably elevated the oxidation-reduction potential, which impeded electron transfer efficiency and promoted the accumulation of intermediate sulfur compounds (e.g., S0 and S2O32−). Furthermore, the presence of B. subtilis and S. cerevisiae also increased the concentrations of longer-chain volatile fatty acids (VFAs), including butyrate and propionate, which are less readily utilized utilization by methanogens, thus contributing to reduced CH4 production. Microbial community analysis revealed that the relative abundance of Desulfobacterota decreased drastically, by 99.06% in the B. subtilis group and 97.97% in the S. cerevisiae group compared to the control. Additionally, genera associated with the production of lactic acid, propionate, and butyrate became more dominant, thereby limiting the availability of substrates for methanogens and further reducing CH4 emissions. Functional prediction analyses corroborated these findings, indicating a reduced abundance of genes involved in sulfate reduction and methanogenesis. Overall, this study demonstrates that S. cerevisiae and B. subtilis effectively reduce H2S and CH4 emissions by altering microbial community composition and metabolic pathways, offering a sustainable approach for wastewater treatment.
Secondary water supply systems (SWSSs) are pivotal in urban water management. Municipal water entering SWSS storage tank undergoes hydraulic stagnation before being distributed to end users. This stagnation provides a stable microenvironment, facilitating a series of chemical reactions, particularly chlorine disinfectant decay resulting in favorable conditions for microbial proliferation. Elevated microbial loads within SWSSs directly compromise the microbiological safety of residential drinking water. In this review, we compile the findings from our studies and existing literature and systematically evaluate the latent microbial hazards in SWSSs serving both urban residential neighborhoods and self-built houses. SWSSs function as persistent reservoirs for pathogenic microbiota. We propose Legionella spp. as targeted supplementary microbiological indicators for routine water-quality monitoring in SWSSs. To mitigate the risks, we advocate implementing three-tiered interventions: 1) an optimized building layout and operation mode, 2) engineered secondary disinfection strategies, and 3) enhanced regulatory oversight through smart monitoring frameworks. In summary, we characterize the microbial contamination mechanisms in urban SWSSs and establish a vital scientific basis for advancing operational management and safety assurance.
At present, excessive carbon dioxide (CO2) emission has become an increasingly prominent global energy and environmental issue. Therefore, effective methods to convert CO2 into fine chemicals are urgently required. Herein, series of S-doped carbon-nitrogen (CNS-X) materials (where X denotes the ratio of thiourea and melamine substances ranging from 0.03 to 0.8) was prepared via the programmed temperature pyrolysis method, which thiourea (CH4N2S) and melamine was used as the precursor of the catalysts. The sulfur source endow the CNS-X acidic sites, which cooperate synergistically with amino groups from the incomplete polymerization of melamine, leading to a bi-functional catalyst for cycloaddition reaction of CO2 with epoxides. These catalysts were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, elemental analysis, X-ray photoelectron spectroscopy, and N2 adsorption-desorption techniques, confirming the successful integration of functional groups. The optimal thiourea doping concentration of 0.4 was certainly found to have considerably facilitated the efficient conversion of CO2 by the CNS-0.4 catalyst, in which the conversion of epichlorohydrin (ECH) could achieve over 90.0% and the selectivity of cyclic carbonate is 98.0% under 1.0 MPa at 140 °C for 10 h. The superior catalytic performance of CNS-0.4 was attributable to the synergistic effect arising from the co-existence of Lewis acidic and basic sites. Notably, using CNS-0.4 resulted in a high yield even after four reaction cycles.
Accumulation of plant- and microbial-derived carbon together determines the stability of soil organic carbon (SOC) pools. To explore the accumulation characteristics and comparative contributions of organic carbon from diverse origins within soil aggregates exposed to microplastic pollution, we conducted corn pot experiments using biodegradable (polylactic acid; PLA) and conventional microplastics (polyethylene; PE) to examine the effects of microplastic pollution on microbial and plant derived carbon in macroaggregates (0.25–2 mm) and microaggregates (< 0.25 mm). Exposure to PE and PLA microplastics diminished the microbial necromass carbon in macroaggregates and its contribution to SOC, whereas their effects on microbial necromass carbon in microaggregates fluctuated depending on microplastic concentration. Due to the increased turnover rates and structural modifications experienced by biodegradable microplastics, PLA treatments yielded superior microbial necromass carbon content than PE treatments. PE reduced plant-derived carbon and its contribution to SOC across both aggregates, whereas PLA exerted a dosage-related effect on plant-derived carbon. Remarkably, 87%–408% of additional SOC in PLA treatment was primarily derived from other carbons, possibly indicating the inclusion of microplastic derived carbon in SOC assessments, thereby inflating SOC estimates. Under microplastic pollution, plant derived carbon dominated the accumulation of SOC in macroaggregates, whereas microbial derived carbon dominated SOC accumulation in microaggregates. Furthermore, macroaggregates exhibited higher SOC concentrations than microaggregates, with PLA treatments demonstrating superiority over PE treatments. Remarkably, microplastics supported the stability of SOC in microaggregates without exerting similar effects on macroaggregates.
Interregional trade facilitates the transfer of implied human economic well-being (HEW) and integrated environmental pressure (IEP). The mismatch between them leads to environmental inequality. A comprehensive evaluation index system for HEW is constructed. Based on the multi-regional input-output (MRIO) model, the HEW, water, carbon, and land footprints of the Hexi Corridor Economic Belt in China were measured in 2012, 2015, and 2017. Three types of environmental footprints were integrated into the IEP, and structural decomposition analysis (SDA) was used to explore the interregional transfer and driving factors of changes in HEW and IEP. A regional environmental inequality (REI) index was constructed to assess the environmental inequality among cities in the Hexi Corridor. Results show that environmental inequality in the Hexi Corridor is severe and intensifying. The focus is that Jiuquan absorbs more HEW from other cities in the interregional trade, but transfers IEP to Jiayuguan and other places. The main factors affecting the flow changes of HEW and IEP are production structure and final demand structure. Due to differences in resource endowments, Jiayuguan bears great environmental pressure without sufficient economic compensation, which is unfavorable for regional coordinated and sustainable development. Therefore, it is recommended to introduce clean production technology, transfer polluting production to reduce the productive environmental footprint of Jiayuguan, develop high-tech, and promote the growth of regional HEW driven by surrounding cities. The study findings help address environmental inequality and promote sustainable growth of economic well-being in Western China and provide a reference for similar research.
UV/H2O2 is commonly used to remove organic micropollutants and frequently paired with activated carbon for further removal of pollutants, addressing issues such as H2O2 residuals, uncontrollable by-products, and energy consumption reduction. Here, we report the changes in the removal characteristics of organic contaminants during the operation of a pilot system based on UV/H2O2 coupled granular activated carbon (GAC) after in situ biofilm formation to generate biologically activated carbon (BAC). We completed the screening of unknown organic matter and molecular-level chemical transformation of 100–1600 Da dissolved organic matter (DOM) using Fourier transform high-resolution mass spectrometry (FT-ICR MS). The FT-ICR MS results indicated that BAC differs from GAC in terms of DOM removal behavior and mechanisms. GAC primarily produces free radicals through synergistic residual H2O2 to further oxidize and remove organics. Low molecular weight (LMW) organics undergo general molecular chemical changes but have modest removal effects. BAC considerably lowered the chemical variety of DOM and eliminated LMW organics through biodegradation and activated carbon adsorption. According to the study findings, UV/H2O2-BAC can more effectively compensate for the drawbacks of individual technologies than UV/H2O2-GAC, with superior removal efficiency of organic pollutants, no residual H2O2, controllable effluent products, and robust performance in real environmental matrices.
This study examines household food carbon emissions in rural China, focusing on the inequality of these emissions and the influence of household characteristics on their variation. Our findings indicate that the average food consumption per rural household is 1031.66 kg. Among all food types, pork contributes the highest share of carbon emissions at 39.75%, followed by beef and mutton at 15.14%, while milk accounts for the lowest share at just 1.38%. Additionally, as household income increases, both food consumption and associated carbon emissions rise accordingly. The food-related carbon emissions tend to be higher in households that are more educated, younger, and larger in size. There are notable regional and income disparities in rural food-related carbon emissions. The regional inequalities appear primarily driven by interactions between different regions, while income inequality is influenced by both intra-group disparities and overlaps among income groups. The results from our threshold regression suggest that carbon emissions are particularly elevated in households where the head has a college-level education or higher, is aged between 32.80 and 33.25 years, and has a household size of three to five members. It is essential to develop and implement flexible policies aimed at reducing the consumption of high-carbon foods. By taking these steps, we can work toward a more sustainable future and promote greater equity in food-related carbon emissions.
