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81. 题目: Clay-organic matter interactions drive microbial necromass preservation in soils
文章编号: N26030611
期刊: Nature Communications
作者: Xu Wang, Cynthia M Kallenbach, Maya Almaraz, Katerina Georgiou, Lifei Sun, Changpeng Sang, Ping Jiang, Yue Liu, Edith Bai, Chao Wang
更新时间: 2026-03-06
摘要: Microbial necromass is increasingly recognized as a major source of stable soil organic matter (SOM), and its persistence is often attributed to interactions with clay-sized minerals. However, the mechanisms underlying this mineral-mediated stabilization remain poorly understood. Here, we conducted an in situ dual-labeled (13C and 15N) microbial necromass experiment across a clay gradient to quantify how clay content and necromass origin (bacterial vs. fungal) regulate necromass persistence. We find that higher clay content markedly enhances necromass retention by strengthening mineral protection, suppressing microbial activity and diversity, and limiting leaching losses. NanoSIMS imaging shows that new necromass preferentially associates with organic matter coatings on the rough mineral surfaces, highlighting organo-organic interfaces as important stabilization pathways. Necromass origin exerts little effect on retention despite marked differences in C:N ratios and bulk chemical composition, indicating that finer-scale molecular features, rather than broad compositional differences, govern necromass stabilization in soils.

82. 题目: UV-activated assisted electrochemical process for mine water deep mineralization and resource recovery
文章编号: N26030610
期刊: Nature Communications
作者: Xiangyun Liu, Youzheng Chai, Yuwei Gu, Yongqi Li, Xiao Wang, Qiancheng Wang, Gong Zhang, Huijuan Liu, Jiuhui Qu
更新时间: 2026-03-06
摘要: High-salinity mine water generated during membrane concentration of mine water contains structurally stable complex organic matter that resists removal and mineralization by conventional advanced oxidation processes, ultimately producing low-value by-product salts that hinder the resource utilization pathway. Leveraging the ultraviolet sensitivity of inherent chromophore groups and conjugated structures, this study developed an ultraviolet-activated assisted electrochemical process. By harnessing ultraviolet/oxidant synergies, this approach achieves ~89.9% total organic carbon removal, with minimal performance decay over 1000 hours. Combined with ultraviolet-visible spectroscopy, fluorescence excitation-emission-matrix spectroscopy, fourier transform ion cyclotron resonance mass spectrometer, and model contaminant experiments, this study elucidates an ultraviolet activation and radical attack synergistic mechanism driving organic mineralization. The direct integration of purified brine with bipolar membrane electrodialysis successfully produces acid, high-purity alkali (>99%), and reusable water, thereby closing the loop of impurities removal and resource recovery. This integrated system offers a strong strategy for high-value resource recovery and sustainable mine water management.

83. 题目: The synergistic effect of algal-bacterial granular sludge in a sequencing batch reactor with tetracycline-containing synthetic livestock and poultry breeding wastewater.
文章编号: N26030609
期刊: Journal of Environmental Management
作者: Yuanda Du, Shoubo Zhao, Yanan Gao, Yujie Yan, Yi Kong, Wenwen Meng, Xinru Lu, Shun Zheng, Haolin Mu, Xiaojing Chen, Qiang Kong
更新时间: 2026-03-06
摘要: The concentration of environmental antibiotics, along with their ecological risk, has increased due to the continuous accumulation of livestock and poultry breeding wastewater (LPBW). In this study, two sequencing batch reactors (SBRs) were established-one equipped with algal-bacterial granular sludge (ABGS) and the other with aerobic granular sludge (AGS)-to investigate the treatment performance of tetracycline containing synthetic LPBW. Pollutant removal efficiency and underlying mechanisms were determined by analyzing the physiological and biochemical properties, dynamic changes in the microbial community, and the fate of antibiotic resistance genes (ARGs). Compared to AGS, ABGS resulted in faster granulation and greater lipid production. Exposure to tetracycline significantly altered the contents of extracellular polymeric substances (EPS) and chlorophyll. During the cultivation stage, the removal efficiencies of TN and TP by ABGS were 7.01% and 1.52% higher, respectively, than those by AGS. However, after tetracycline was added, the TN and TP removal efficiencies of ABGS decreased by 0.77% and 6.91%, respectively, compared to those of AGS. The tetracycline removal efficiency of ABGS reached 86.32%, which was 4.49% greater than that of AGS. Metagenomic analysis revealed that the relative abundances of Pseudomonas and Stenotrophomonas (key tetracycline-degrading bacteria) in ABGS were 36.61% and 66.82% greater, respectively, than those in AGS. After tetracycline was added, the relative abundances of tetracycline-related ARGs (tetX and MuxB) increased by 36.01% and 61.68%, respectively, in AGS but decreased by 53.98% and 5.71%, respectively, in ABGS. In this study, ABGS exhibited outstanding performance in enhancing the removal of pollutants from tetracycline-containing synthetic LPBW in SBR systems.

84. 题目: Enhanced removal of estradiol by Twice-ball milled magnetic biochar: Mechanisms and efficiency.
文章编号: N26030608
期刊: Journal of Environmental Management
作者: Haoxuan Cai, Yuqing Liu, Yujuan Wen, Xiaochu Wang, Yunlong Wang, Yuesuo Yang, Xiaoming Song
更新时间: 2026-03-06
摘要: Steroid estrogens (SEs) threaten ecosystems and human health. Biochar is an efficient adsorbent for SEs removal due to its porous structure, yet single-modified biochar's capacity is unstable and its mechanisms are poorly understood. Therefore, this study prepared Twice-ball milled magnetic biochar (TmMBC) through a secondary ball milling combined with potassium ferrate (K2FeO4) modification. By integrating adsorption kinetics, isothermal experiments, and soil column migration tests, this study systematically investigated the removal performance and mechanisms of TmMBC for estradiol (E2). The results indicated that TmMBC has a specific surface area of 683.51 m2/g, with a micropore area increased to 659.70 m2/g. At pH 7 and 15 °C, the maximum adsorption capacity for E2 (1 mg/L) was 56.30 mg/g, which is a 40.75% enhancement compared to Ball milled biochar (BmBC). Kinetic studies demonstrated that the adsorption process of TmMBC conforms to a pseudo-second-order kinetic model (R2 > 0.98), indicating that chemical adsorption is predominant. Additionally, the analysis of environmental factors showed that TmMBC maintains efficient adsorption (>45 mg/g) within the pH range of 3-9, and the presence of Ca2+ can further enhance its adsorption capacity by 37.6%. In the soil column experiment, the addition of 0.1 mg TmMBC can delay the penetration time of E2 to over 40 pore volumes (pv), achieving a retention rate of 100%. In contrast, the addition of microplastics (PE, PLA) and cow dung affects the migration behavior of E2 to varying degrees. The study confirms that TmMBC significantly enhances the adsorption and fixation capacity of E2 through the synergistic effects of graded pore structure, Fe-O active sites, and surface functional groups. This research provides theoretical support for the development of efficient and low-cost technologies for E2 pollution remediation, while also offering new insights into the application of biochar in agricultural pollution remediation.

85. 题目: Mechanistic Insights into PFAS Adsorption on Microplastics: Effects of Contaminant Properties and Water Chemistry.
文章编号: N26030607
期刊: Environmental Research
作者: Md Saiful Islam, Gangadhar Andaluri
更新时间: 2026-03-06
摘要: Microplastics (MPs) and perfluoroalkyl substances (PFAS) frequently coexist in aquatic environments, where their co-occurrence has raised concern due to combined exposure risks. MPs provide a large surface area and reactive interface for contaminant adsorption, making them potential carriers for PFAS transport. This study investigates the adsorption behavior of two widely detected PFAS, perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), onto five common MPs. Batch experiments were conducted to evaluate the influence of MPs, PFAS molecular properties, and key environmental factors including natural organic matter (NOM), ionic strength, and pH. The adsorption capacity followed the order PFOS > PFOA for all polymers, with maximum adsorption ranging from 35.54 to 43.34 μg⋅g-1 for PFOA and 38.16 to 49.92 μg⋅g-1 for PFOS and the overall affinity increased in the order PVC < PA < PS < PP < PE. Sorption kinetics were best described by the pseudo-second order model, while equilibrium data were more consistent with the Langmuir model, suggesting predominantly monolayer-type adsorption behavior dominated by hydrophobic and electrostatic interactions. Environmental conditions strongly influenced PFAS adsorption, with increasing pH and NOM reducing adsorption by more than 65 percent and up to 76 percent respectively, while higher ionic strength increased adsorption. Fourier transform infrared spectroscopy and principal component analysis revealed changes on MP surfaces after adsorption, while molecular orbital analysis confirmed differences in reactivity between PFOS and PFOA. Overall, these findings demonstrate that MPs can act as carriers for PFAS, especially in saline waters, highlighting their importance in PFAS fate and exposure pathways.

86. 题目: The Dual Role of NPP in Mediating and Moderating Climate-Soil Carbon Pathways Under Warming and Drought Across European Ecosystems
文章编号: N26030606
期刊: Global Change Biology
作者: Yang Lu, Lin Yang, Chenghu Zhou
更新时间: 2026-03-06
摘要: Soil carbon dynamics in response to climate change hold critical implications for global carbon cycling and ecosystem resilience. Net primary productivity (NPP), the dominant source of soil carbon inputs, serves dual functions: it mediates climate effects via carbon input fluxes and moderates them by altering the intensity of climate impacts on soil carbon. In this study, we assembled a dataset of soil organic carbon (SOC; hereafter OC) and its fractions—particulate organic carbon (POC) and mineral-associated organic carbon (MAOC)—from 8147 repeated sampling sites across the European region in 2009 and 2018. Using structural equation modeling with joint mediation and moderation analysis across three major land uses, we identified two functionally distinct, context-dependent roles of NPP. NPP acts as a mediator: favorable climate increases belowground inputs and promotes OC accumulation, primarily through the formation and stabilization of MAOC. NPP also acts as a moderator: it amplifies temperature's negative impacts on soil carbon, with POC being most sensitive to warming. The effects of NPP on the relationship between climatic moisture and soil carbon exhibited a nonlinear reversal: under humid conditions, NPP mainly reduced decomposition-driven carbon loss, whereas under drought conditions, it enhanced input-driven carbon accumulation. In contrast, soil moisture consistently showed a stable positive influence, continuously supporting carbon inputs and accumulation. Cross–ecosystem comparisons show that forests rely more strongly on NPP-driven input and regulatory pathways, whereas in cropland the mediating and moderating roles of NPP are comparatively weaker, making soil carbon more directly influenced by climate. Overall, NPP plays a dual role in the climate–soil carbon pathway: as both a source of input enhancement and a marginal amplifier, representing a functional trade-off under climate change scenarios.

87. 题目: Unraveling mercury dynamics in shallow lakes: Evidence from a pristine oligotrophic lake in a natural mercury hotspot of the Patagonian Andes
文章编号: N26030605
期刊: Chemosphere
作者: Zaida Fernandez, Carolina Soto Cárdenas, Marina Arcagni, Andrea Rizzo, María C Diéguez
更新时间: 2026-03-06
摘要: Natural hotspots of mercury (Hg) in pristine regions are suitable systems for assessing climate and environmental drivers of Hg cycling. In this study, we address the dynamics of Hg in an oligotrophic lake impacted by volcanic eruptions and devoid of direct anthropogenic disturbances. We focused on the dynamics of Hg concentration, partitioning, and availability in Lake Pire (Northwestern Patagonia, Argentina), between March 2021 and December 2022. Water samples were analyzed for total, filtered, and particulate Hg concentrations (THg, FHg and PHg, respectively), as well as for physicochemical variables including the concentration and quality of dissolved organic matter (DOM). Seasonal hydrological inputs drove the DOC concentration and quality, influencing Hg mobility and partitioning in the lake. During the wet period high concentrations of PHg coincided with humic allochthonous DOM, while snowmelt runoff diluted PHg and DOC concentrations. In contrast, in the dry period high FHg concentrations were recorded along with highly aromatic DOM, resulting from internal processing and diffusion from the sediment. The co-transport of Hg, DOM, and particulate matter from the catchment was limited to periods of high hydrological connectivity, when homogeneous Hg concentrations were recorded in the lake profile (wet: up to 82.42 ng/L; snowmelt: up to: 73.4 ng/L). In the dry period, with low hydrological connectivity, the lake exhibited direct thermal stratification and higher Hg concentrations (up to 365 ng/L) in deeper layers. DOM quality enabled tracking terrestrial Hg inputs and sediment contribution. High PHg concentrations coincided with chlorophyll a peaks, suggesting Hg accumulation in phytoplankton and incorporation at the base of the pelagic food web.

88. 题目: Mechanism of pyrene remediation in soil by biochar-immobilized laccase
文章编号: N26030604
期刊: Environmental Research
作者: Babar Hussain, Sami Ullah, Nadeem Iqbal, You Wu, Hui Ma, Chenglong Yu, Shiyong Sun, Shengyan Pu
更新时间: 2026-03-06
摘要: Pyrene accumulates in soil from a variety of sources, infiltrating the food chain and causing mutagenic and carcinogenic disorders in humans. Pyrene has since been effectively removed from soil using a variety of chemical and physical remediation techniques, but these approaches have a number of disadvantages, including being costly, time-consuming, labor-intensive, and producing secondary environmental pollutants. Therefore, this work employed an environmentally friendly and sustainable chemical approach that utilized enzyme immobilization. Wheat straw biochar prepared by pyrolysis, acid activation, where laccase was immobilized on biochar using the cross-linked adsorption technique. Results showed that immobilized enzyme retained over 50% of enzyme activity at pH 3–7, 20–60 °C, and maintained over 50% relative activity after five cycles and 50 days of storage. Pyrene remediation reached 80.33% after 50 days of incubation while quadratic model indicated the remediation efficiency will increase over time, reaching 53.56%. Soil phenol peroxidase, peroxidase, and dehydrogenase activities increased by 105.2-107.1%, 155.1-167.2%, and 104.8-157% respectively compared to control. Firmicutes, Actinobacteria, and Proteobacteria were the dominant phyla, while Bacillus, Lysinibacillus, Sedimentibacter, Brevundimonas, Christensenellaceae_R-7_group, Sphingobium, and Stenotrophomonas were the most abundant genera in immobilized enzyme treatments. These microbes involved in the degradation of pyrene and various organic contaminants in the soil. Thus, it may be concluded that laccase immobilization on wheat straw biochar is a green and sustainable method for pyrene remediation in soil, as well as suitable for agricultural and industrial applications.

89. 题目: A RothC-based spatiotemporal analysis of soil organic carbon stocks in agricultural soils of the Netherlands (1986–2022)
文章编号: N26030603
期刊: Geoderma
作者: Yuqing Lai, Vera L Mulder, Gerard B M Heuvelink, Hans Kros, Gerard H Ros
更新时间: 2026-03-06
摘要: Soils are the largest terrestrial carbon reservoir, with soil organic carbon (SOC) playing a critical role in maintaining soil quality and associated ecosystem services. Accurately estimating SOC stocks at high spatial and temporal resolution over large scales remains challenging, particularly in agricultural systems where carbon inputs are often uncertain or unavailable. In this study, we used the RothC model to simulate SOC stocks in Dutch agricultural mineral soils from 1986 to 2022, at 25 m × 25 m resolution. We examined the temporal and spatial variation of the total SOC stock and its distribution over RothC carbon pools and unravelled how livestock manure inputs and land use affect the observed trends. Averaged SOC stocks in the topsoil (0 – 30 cm) increased by 13.2% under grassland, decreased by 10.4% under cropland, and decreased by 3.9% in areas with changing land use. Carbon gains in grassland were linked to systematically higher manure inputs and accumulation in stable pools, whereas lower manure inputs and more intensive management led to declining labile SOC pools. Independent validation on three spatial datasets showed the highest model performance for point-based field data (model efficiency coefficient MEC = 0.32 in 1986 and 0.37 in 2022). Observed changes in SOC over time could be less well reproduced (MEC ≈ 0) across all datasets, but simulated spatiotemporal patterns were consistent with previous observational studies. The study illustrates the potential of RothC for national-scale SOC stock assessment and monitoring, while highlighting the need for improved input data and temporal validation data. Importantly, this modelling approach effectively captures SOC stock dynamics, which remains challenging for purely empirical, statistical models. Future work could benefit from hybrid modelling approaches that integrate RothC with machine learning, enhancing the ability to capture currently unexplained variability and improve simulation performance.

90. 题目: Priming indigenous microbial manganese oxidation with aged biochar for cadmium immobilization in acidic soils
文章编号: N26030602
期刊: Chemical Engineering Journal
作者: Yongchao Li, Yangxin Zhai, Chuanfeng Zhou, Anqi Bu, Yanming Wang, Yesheng Huang, Shengdao Shan
更新时间: 2026-03-06
摘要: The remediation mechanisms of commercially prevalent aged biochar for cadmium (Cd) in acidic soils, particularly its role in mediating endogenous manganese (Mn) cycling, remain unclear. Through a 180-day in-situ microcosm study integrating chemical speciation, mineralogy, metagenomics, and transcriptomics, we demonstrated that aged straw biochar (stored for ~3 years) functioned primarily as a microbial metabolic primer rather than a direct sorbent. It elevated soil pH by 0.5–1.2 units and increased organic carbon by ~12.6 g·kg−1, which selectively enriched indigenous Mn-oxidizing bacteria (e.g., Burkholderia, Chryseobacterium) and upregulating key functional genes (mnxG + 97.2%; copA + 50.0%). This activated microbiome drove the oxidative conversion of acid-soluble Mn to reducible Mn oxides, evidenced by birnessite/pyrolusite formation and sterile controls verifying microbial dependence. Crucially, the transformation of acid-soluble Cd into reducible fraction was significantly enhanced in biochar-treated soils, exhibiting a net decrease of 0.25 mg/kg at the 1% application rate with a distinct temporal lag behind Mn oxidation. Mantel tests and partial least squares path modeling (PLS-PM) identified soil pH as the environmental central driver. While both direct and indirect pathways contributed, the microbial mediated biogenic Mn oxides formation was the pivotal process controlling Cd sequestration. These findings revealed that aged biochar remediated Cd by reprogramming the soil microbiome to harness endogenous Mn, offering a novel strategy for heavy metal stabilization in acidic soils.

91. 题目: Optimization of an anammox-based microalgal-bacterial symbiosis system for enhanced EPS production and removal nitrogen and phosphorus
文章编号: N26030601
期刊: Chemical Engineering Journal
作者: Ziyu Qiao, Mengdie Hu, Li'e Wei, Kailun Song, Zhen Bi, Xin Yin
更新时间: 2026-03-06
摘要: The microalgae–bacteria symbiotic system (ABSS) demonstrates outstanding advantage with efficiently removing nitrogen and phosphorus in wastewater. The abundant production of extracellular polymeric substances (EPS) is crucial for maintaining ABSS performance. However, the quantitative relationship between the operational conditions for establishing ABSS and EPS production remains unclear. In this study, the ABSS was established using Chlorella vulgaris (C. vulgaris) and anaerobic ammonium-oxidizing (anammox) bacteria. Batch experiments showed that the optimal conditions were a microalgae–bacteria ratio of 0.5 g:15 g, 25 °C, 8 h illumination, and influent NH₄+–N, NO₂−–N, and PO₄3−–P concentrations of 50, 65, and 3 mg/L, respectively. Under these conditions, TN and PO₄3−–P removal efficiencies reached 60.24% and 85.63%. At the same time, the EPS concentration reached 32.18 mg/L. Multiple regression analysis revealed that EPS production was significantly influenced by the inoculum ratio, with a contribution of 0.649. Furthermore, the ABSS exhibited a 211.25% increase in PO₄3−–P removal efficiency compared with the bacteria system (BS), and a 115.33% increase in TN removal efficiency compared with the microalgal system (AS) during 210 days in a sequencing batch reactor. Compared with the initial anammox bacteria, the abundance of anaerobic ammonium-oxidizing bacteria (AnAOB) in the ABSS decreased by 40.92%, while the denitrifying bacteria (DnB) increased by 34.26%. A denitrification-dominated nitrogen removal pathway complemented by anammox activity was established in ABSS. By optimizing the operating conditions of the ABSS, this study clarified the factors influencing EPS production providing an effective basis for the rapid removal of nutrients from wastewater.

92. 题目: Triazine-induced extracellular polymeric substance disruption drives metabolic reprogramming and enhanced volatile fatty acid production in anaerobic sludge fermentation
文章编号: N26030510
期刊: Bioresource Technology
作者: Jingyang Luo, Shumeng Yang, Qian Feng, Xiang Zou, Yang Wu, Feng Wang
更新时间: 2026-03-05
摘要: The accumulation of antimicrobial contaminants in waste-activated sludge (WAS) posed challenges to anaerobic fermentation processes, with mechanistic impacts on volatile fatty acids (VFAs) production remaining poorly understood. 1,3,5-triazine (triazine), a widely detected triazine-based antimicrobial agent, paradoxically enhanced VFAs production in a concentration-dependent manner, achieving maximum yields of 1771 mg COD/L (18.4-fold increase compared with control). Enhanced production was accompanied by a distinct metabolic shift from propionate to acetate dominance (from 38.7 to 54.3%), driven by systematic disruption of extracellular polymeric substances (EPS), especially proteins. Molecular docking revealed that triazine induced conformational instability and structural damage in proteins through hydrogen bonding and hydrophobic interactions. Meanwhile, the increase in ammonium nitrogen concentration under triazine stress provided further confirmation of the hydrolysis of proteins, providing readily fermentable substrates for VFAs production (particularly acetate). High-throughput 16S rRNA sequencing uncovered concentration-dependent microbial community restructuring, characterized by enrichment of proteolytic bacteria (Petrimonas) and acetate producers (Anaerovorax), concurrent with the suppression of methanogens. Functional metagenomic analysis using PICRUSt2 revealed upregulation of proteolytic enzymes (e.g., EC:3.4.16.4) and acetyl-CoA synthesis genes (e.g., PDHA), facilitating enhanced protein hydrolysis and acetate biosynthesis. Critically, triazine stress activated quorum sensing and two-component regulatory systems, with luxS expression increasing 5.7-fold, promoting metabolic coordination and stress resilience rather than community collapse. Partial least squares path modeling confirmed that substrate availability (λ = 0.459) served as the primary driver of VFAs accumulation, mediated by microbial community adaptation (λ = 0.560). These findings unveil how antimicrobial stress enhanced resource recovery via EPS-mediated metabolic reprogramming.

93. 题目: Macrophyte Restoration Alters Sedimentary Organic Matter-Microbes-Environment Interactions and Enhances Carbon Sequestration in Lake Sediment
文章编号: N26030509
期刊: Water Research
作者: FengTing Wu, ShiLin An, JingJing Liu, YueHan Lu, Hu He, XiaoZi Chang, Qi Leng, ShengHao Zhang, Peng Xing, KuanYi Li, YingXun Du
更新时间: 2026-03-05
摘要: Lake eutrophication is a widespread challenge, and macrophyte reconstruction has been shown as an effective strategy for restoring shallow eutrophic lakes. However, the impacts of macrophyte on the sedimentary carbon sequestration and underlying mechanisms remain poorly understood. Here, we conducted a year-long field investigation to compare the difference in the macrophyte-restored and unrestored areas within a typical urban lake, analyzing the physicochemical properties, the composition of organic matter, as well as the microbial community. Compared to the unrestored areas, macrophyte-restored areas showed ∼80% higher total sedimentary carbon, along with lower sediment pH and increased aromaticity (SUVA₂₅₄) and humification (HIX) of both water-soluble and alkaline-extractable organic matter. In addition, the sediments in the restored areas had a higher microbial richness and a microbial community more enriched in Alphaproteobacteria. Partial least squares-path modeling revealed that enhanced carbon sequestration by macrophyte restoration was primarily driven by the shifts in sedimentary organic matter composition. Reduction in labile substrates (e.g., peptides and protein-like components), coupled with lower sediment pH, shifted the microbial community toward taxa associated with enhanced carbon persistence (Alphaproteobacteria). Overall, our results demonstrate that macrophyte restoration enhances sediment carbon sequestration through initiating shifts in sedimentary organic matter composition that subsequently restructure organic matter–microbe–environment interactions. This study provides direct evidence that macrophyte restoration, as a nature-based solution widely applied in shallow eutrophic lakes, can contribute to carbon sequestration beyond its well-recognized role in water quality improvement.

94. 题目: Molecular-weight-dependent mixing behavior of organic phosphorus and carbon in a subtropic river-estuary-bay continuum
文章编号: N26030508
期刊: Water Research
作者: Cheng Xu, Ying Huang, Bin Yang, Renming Jia, Zhiming Ning, Bo Yang, Lei Xie, Lin Yang, Dongliang Lu, Zhenjun Kang, Laodong Guo
更新时间: 2026-03-05
摘要: Organic phosphorus (OP) and organic carbon (OC) are significant components of potentially bioavailable organic matter reservoir and key drivers of eutrophication in aquatic environments. However, the dynamics of their chemical speciation, transformation, and coupling mechanisms along the river-estuary continuum remain poorly understood. To bridge this knowledge gap, we quantified dissolved, colloidal, and particulate OP and OC in the Qinjiang River estuary in the northern Beibu Gulf during July 2023. Dissolved OP (DOP) and dissolved OC (DOC) were further fractionated into different size-fractions using ultrafiltration devices equipped with membranes with different molecular weight cutoffs of 10 kDa, 30 kDa, and 50 kDa. The >10 kDa colloidal OP (COP) constituted 63 ± 17% of the bulk DOP, indicating that most DOP occurred in colloidal form, whereas colloidal OC comprised 44 ± 14% of the bulk DOC, suggesting that DOC predominantly partitions in the <10 kDa dissolved phase. In addition, DOP and DOC had distinct estuarine mixing behavior. DOP was rapidly removed, attributable to its strong particle reactivity and high biological uptake, while DOC exhibited largely conservative mixing due to continuous riverine inputs and the presence of refractory components within the bulk DOC pool. The percentage of particulate OP in the total OP decreased sharply from 69% in river water to 14% in the lower estuary, while the <10 kDa low-molecular-weight DOP (LMW-DOP) increased dramatically from 9% to 64% along the river-estuary transect, reflecting a dynamic transfer from particulate to dissolved phases, likely related with in situ production of bioavailable LMW-DOP from biological activities in the bay. Riverine colloidal organic matter (COM) was dominated by medium- to large-sized fractions with higher C/P ratios indicating sources from P-limited terrestrial/river systems or contributions from highly degraded terrestrial COM. In contrast, river-derived small-sized COM was diagenetically fresher with lower C/P ratios and greater potential bioavailability. Preferential biological removal of bioavailable small-sized COP (10–30 kDa) further increased C/P ratios in estuarine and open bay waters. These findings highlight the distinctive role between OP and OC and among different colloidal size-fractions in regulating biogeochemical cycling of dissolved organic matter and nutrients in the river-estuary-bay continuum.

95. 题目: Organic Selenium Quality and Quantity in Soils Are Related to Organic Matter Composition and Driven by Land Use
文章编号: N26030507
期刊: Environmental Science & Technology
作者: Maja B Siegenthaler, Lenny H E Winkel, Reto G Meuli, Julie Tolu
更新时间: 2026-03-05
摘要: The micronutrient selenium (Se) exhibits a narrow range between essentiality and toxicity. In soils, Se speciation influences its mobility and plant availability, with implications for addressing unsafe Se levels in plant-based nutrition. We investigated how Se speciation varies with the molecular composition of organic matter (OM) in 92 Swiss topsoils spanning different land uses (i.e., croplands, grasslands, and forests). OM composition was characterized using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), while Se speciation was determined in NaOH extracts using size exclusion chromatography coupled to UV and elemental mass spectrometry (SEC-UV-ICP-MS/MS). We found that Se speciation strongly relates to OM decomposition status and pH, and drastically differs between soil land uses. Cropland soils exhibited higher proportions of Se oxyanions and small hydrophilic organic Se, whereas forest and grassland soils contained more larger, aromatic organic Se compounds. Overall, these larger Se forms correlated with fresh and/or poorly decomposed, plant-derived OM, while oxyanions and small hydrophilic Se were linked to decomposed OM. Additionally, Se extractability by NaOH decreased with increasing soil pH, which may be due to stronger SOM stabilization, microbial processes, or higher Ca contents at higher pH. These results have important implications for Se plant availability considering land use changes and SOM degradation.

96. 题目: Physicochemical Properties and Aging Behavior of Black Carbon across Emission Sources Determined by Char and Soot Subgroups
文章编号: N26030506
期刊: Environmental Science & Technology
作者: Junjie Cai, Yingjun Chen, Jun Zeng, Hongxing Jiang, Yong Han, Min Cui, Yu Peng, Zeyu Liu, Gan Zhang, Jianmin Chen
更新时间: 2026-03-05
摘要: The physicochemical properties and atmospheric aging behavior of black carbon (BC) are critical for assessing its climatic impact, yet how these vary across emission sources remains poorly understood. Here, the relationship between the microphysical properties and aging processes of BC subgroups (Char and Soot) from major emission sources, including biomass burning (BB), diesel vehicle exhaust (DV), and industrial coal combustion (ICC) were investigated at single particle level. Our results revealed that BB emissions contained 84 ± 5% Char, significantly higher than DV/ICC sources (17–30%). The monomer diameter (dm) and graphitic interplanar spacing of BB-derived BC were twice of those DV- and ICC-derived BC, and the aggregate diameter (da) and O/C ratio were approximately 10-fold higher, along with a weaker degree of necking. Based on the high-time-resolution sampling analysis of BB processes, we found that lower combustion efficiency favored Char formation, resulting in the increasing of dm, da, and O/C ratio of BC particle. Moreover, under equivalent aging, Soot-dominated DV-BC aggregates grew 50% in da versus only 2% for Char-dominated BB-BC. This work demonstrates that the proportion of Char and Soot determine BC’s physicochemical properties and aging behavior in different sources, emphasizing the need for subgroup-specific parametrizations in climate models.

97. 题目: Toward Reliable Environmental Monitoring with Potentiometric Ion Sensors: Unveiling the Effects of Humic Acids and Developing Antifouling Sensors Based on a Poly(vinylidene fluoride) Coating
文章编号: N26030505
期刊: Analytical Chemistry
作者: Yuanxin Liu, Zhibo Liao, Wei Yang, Longbin Qi, Wei Qin
更新时间: 2026-03-05
摘要: Although potentiometric ion sensors have attracted growing interest in the environmental analysis of water quality, reliable long-term continuous monitoring with these sensors remains a great challenge. Fouling of the sensor membranes can seriously impair analytical performance. As a major fraction of natural organic matter, humic acids (HAs) are widespread in natural waters. Here, for the first time, we investigated the influences of HAs as foulants on polymeric membrane ion-selective electrodes (ISEs). It was found that HAs could adsorb on the sensor surface and penetrate the membranes, thus causing potential drifts and reduced sensitivity. To mitigate these effects, we modified the ISEs with a poly(vinylidene fluoride) coating. Owing to its low surface energy and high electronegativity, the functional layer could significantly enhance the resistance of the sensors to HAs. The practical applications of the proposed environ-compatible sensors were validated via long-term (30 days) in situ monitoring of CO32– (pCO2) in the coastal area of the Yellow Sea of China. These findings may provide new insights into reliable environmental monitoring with potentiometric ion sensors.

98. 题目: Mg–modified sludge biochar for enhanced removal of Rh–B and MO: Adsorption characteristics and mechanisms
文章编号: N26030504
期刊: Journal of Environmental Chemical Engineering
作者: Xia Zhao, Jinlong Hu, Yong Yang, Haonan Wang, Xinyu Liu, Xinyi Luo
更新时间: 2026-03-05
摘要: Although the conversion of sludge into biochar represents a promising waste–to–resource technology, its limited adsorption capacity remains a significant challenge. Herein, a magnesium–modified sludge biochar (MKSC) targeting the efficient removal of Rhodamine B (Rh–B) and Methyl Orange (MO) was synthesized through sequential sludge pyrolysis, KHCO3 activation, and MgCl2·6H2O modification. The results revealed that MKSC was enriched with functional groups like –OH, –C–O, –C=O, and Mg–O, in addition to Mg2+. Its surface area rose from 163.43 to 212.60 m2/g and formed a well–defined porous structure. Mg–modification markedly enhanced the adsorption performance of MKSC, with Rh–B and MO removal rates increasing from 78.78% to 97.75% and 81.95% to 98.94%, respectively, accompanied by maximum adsorption capacities of 312.5 mg/g and 120.5 mg/g. The adsorption processes followed the PSO kinetic and Langmuir isotherm models, with the mechanisms of MKSC for Rh–B and MO involving pore filling, hydrogen bonding, electrostatic attraction, surface complexation, and π–π interactions. The synergistic effect of Mg2+ with surface functional groups is crucial for enhancing adsorption performance. This study paves a novel approach for the resource utilization of sludge and significantly improves the adsorption capability of sludge–derived biochar for Rh–B and MO pollutants.

99. 题目: Deciphering the mechanism of carbon transformation during composting regulated with Mg-modified biochar: Insights from microbial and molecular characterization
文章编号: N26030503
期刊: Journal of Environmental Chemical Engineering
作者: Xuhan Gu, Jingchen Song, Hui Li, Yixun Shi, Jiahui Wang, Jijin Li, Shuyan Li
更新时间: 2026-03-05
摘要: Carbon loss and insufficient humification are critical bottlenecks in the aerobic co-composting of organic solid wastes. To address these issues, Mg-modified biochar (MBC) was introduced as an additive to regulate the carbon transformation process. Two-dimensional correlation spectroscopy of fourier transform infrared spectroscopy (FTIR-2DCOS), three-dimensional excitation emission matrix-parallel factor analysis (EEM-PARAFAC) and metagenomic analyses were selected to reveal the mechanism of organic matter degradation and humus formation from the microbial and molecular levels. Results indicated that Mg-modified biochar increased the humic acid content by 21% and reduced carbon dioxide (CO2) and methane (CH4) emissions by 18% and 34%, respectively, with its enhanced surface area, oxygen-containing functional groups, and microbial activity. EEM-PARAFAC analysis revealed that MBC enhanced microbial degradation activity, promoting the conversion of protein-like substances into humic acid-like components, and increasing Fmax, FRI, and HIX values. FTIR-2DCOS elucidated that MBC drove the Maillard reaction by promoting the degradation of polysaccharides into reactive carbonyl precursors (e.g., reducing sugars). MBC enhanced the initial condensation between amino groups and carbonyls, facilitating C–N bond formation and the subsequent polymerization of intermediates into stable humic acid-like components. Furthermore, MBC up-regulated the expression of carbon fixation genes (cbbL, rpiA) and suppressed methanogenesis gene (mcrA) to enhance carbon fixation capacity and reduce methane emission, respectively. Thus, Mg-modified biochar could serve as a sustainable composting additive to enhance composting humification and reduce greenhouse gas emissions.

100. 题目: Environment-driven regulation of EPS secretion and interfacial coupling in microalgae-microplastic hetero-aggregates: insights from molecular mechanisms to utilization potential
文章编号: N26030502
期刊: Journal of Hazardous Materials
作者: Kaiwei Xu, Ke Liu, Xiaotong Zou, Zhou Shen, Shaohua Zhao
更新时间: 2026-03-05
摘要: Microplastics (MPs), as emerging pollutants, have been increasingly detected in aquatic ecosystems, where their interactions with microalgae critically influence pollutant transport and ecological risks. This study aimed to elucidate how different nutrition levels and MPs types regulate extracellular polymeric substance (EPS) secretion and hetero-aggregation behavior of Scenedesmus sp. A combination of experimental observations and density functional theory (DFT) simulations was used to investigate the interfacial interactions between Scenedesmus sp. and two representative microplastics, polystyrene (PS) and polyvinyl chloride (PVC), while metabolomic profiling was conducted to examine the corresponding biochemical responses. Results showed that PS exposure induced the formation of larger and looser flocs with a maximum sedimentation efficiency of 99.63%, whereas PVC resulted in smaller and denser aggregates (93.57%). DFT analysis further demonstrated that PS-EPS interactions were dominated by delocalized van der Waals and hydrogen-bonding forces, whereas PVC-EPS complexes involved localized polar interactions mediated by proteinaceous EPS. Metabolomic analysis indicated that both PS and PVC disturbed purine metabolism and lipid remodeling, with PVC additionally activating amino acid and nitrogen metabolic pathways. Overall, nutrition levels and MPs types jointly modulated EPS composition, interfacial coupling, and aggregation characteristics. This study provides molecular-level evidence for understanding the interfacial mechanisms between microplastics and microalgae. The resulting hetero-aggregation could be further utilized for biodiesel production, enabling the valorization and conversion of waste materials.