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241. 题目: Spatiotemporal dynamics of riverine dissolved organic matter and its linkages to cryospheric changes in the Qilian mountains
文章编号: N26092804
期刊: Catena
作者: Mengxue Chen, Aijun Bu, Shichang Kang, Hewen Niu
更新时间: 2026-09-28
摘要: The biogeochemistry of dissolved organic matter (DOM) in glacial ecosystems is pivotal for understanding climate change. As a typical mid-latitude cryospheric system, the Qilian Mountains are an ideal zone for assessing these processes. However, the studies of the characteristics and migration of DOM in multiple water bodies are still scarce. Through extensive field sampling and measurements, this study systematically evaluates the spatiotemporal characteristics of dissolved organic carbon (DOC), total dissolved nitrogen (TDN), and dissolved organic nitrogen (DON) across six alpine rivers and two glacierized mountain sites in the high-altitude Qilian cryosphere. During the ablation period, mean riverine DOC concentration across the six rivers was 0.81 ± 0.16 mg L−1, with pronounced spatial variability among sites. DOC concentrations were generally higher during the ablation than the non-ablation period, reflecting the influence of seasonal climatic and hydrological conditions. Snow DOC concentrations were lower during the ablation period. Alpine streams receiving substantial glacial meltwater inputs in the Qilian Mountains (Laohugou, Ningchan and Gangshika rivers) exhibited markedly lower DOC concentrations than other less glacier-influenced rivers (Longchang, Babao, and Yeniugou rivers). DOC and TDN concentrations in water samples generally decreased with increasing elevation across the Qilian Mountains. C:N ratios were higher in lower-elevation rivers than in glacierized headwaters, indicating a downstream shift in DOM stoichiometry associated with changes in source contributions and in-stream biogeochemical processing. DOC and DON export from the Longchang River varied seasonally and tracked discharge. Along the elevation transect, DOC and TDN concentrations increased from high-elevation snow and ice to meltwater and downstream river water. Cryospheric retreat may enhance terrestrial DOC and DON inputs and alter their seasonal export, thereby linking changes in cryospheric hydrology with downstream carbon and nitrogen cycling. These findings are critically important for advancing our understanding of carbon and nitrogen cycling in the Qilian cryosphere and glacial ecosystems.

242. 题目: The late shoulder season modifies the mobility of iron and dissolved organic carbon in rivers from distinct permafrost regions
文章编号: N26092803
期刊: Chemical Geology
作者: Maëlle Villani, Catherine Hirst, Eléonore du Bois d'Aische, Cécile Osy, Maxime Thomas, Philippe Roux, Erik Lundin, Justin Ledman, Edward A G Schuur, Sophie Opfergelt
更新时间: 2026-09-28
摘要: Rivers are important suppliers of iron (Fe) and dissolved organic carbon (DOC) from land to sea. While elemental transport in Arctic rivers has been studied mainly during summer, their mobility during the late shoulder season (i.e., the transition between the end of summer and the beginning of winter) remains poorly constrained. Here, we investigate how Fe and DOC mobility evolve during the late shoulder season in two rivers from distinct permafrost regions and hydrological conditions (in Alaska, USA and Abisko, Sweden). Iron and DOC were characterized using their concentrations, percentage of colloidal Fe, and indirect Fe-oxides tracers (Ce anomaly and δ30Si). We show two contrasting processes: (i) in Alaska, progressive river ice formation coincides with a shift toward groundwater-dominated river input, suggesting aggregation of Fe as particles (>0.22 μm), evidenced by a decrease in Fe concentrations in the filtered water (<0.22 μm) over the late shoulder season; the concurrent higher negative Ce anomaly, and the decrease in DOC concentrations, further suggest the aggregation of particulate Fe-oxides associated with DOC; (ii) in Abisko, warmer and near-stagnant river conditions sustain soil pore water-river connectivity over the late shoulder season, enabling lateral transfer of Fe, evidenced by increase Fe concentrations; the increase in the percentage of colloidal Fe, the lower negative Ce anomaly, the slight decrease in δ30Si, and the increase in DOC concentrations, further suggest an increase in colloidal Fe-oxides associated with DOC (1 nm- 0.22 μm) in the river. These contrasting Fe size ranges have direct implications for Arctic DOC export.

243. 题目: Methane and carbon dioxide emissions from wastewater treatment units linked to DOM stabilization and phosphonate-scavenging microbiomes
文章编号: N26092802
期刊: Water Research
作者: Xinlin Zhang, Jinze He, Lei Lv, Hongyang Cui, Yumeng Wang, Xu Zhang, Jie Lv
更新时间: 2026-09-28
摘要: Municipal wastewater treatment plants (WWTPs) are major engineered facilities for urban carbon removal, yet methane (CH4) formation and source mechanisms in downstream stages after aeration and biological nutrient removal remain poorly resolved. Process resolved monitoring at a full-scale WWTP showed that CH4 emissions were concentrated upstream, while measurable fluxes persisted in downstream sedimentation and denitrification units. Dissolved CH4 profiles showed strong attenuation of influent derived CH4 during upstream treatment, followed by a local increase after secondary clarification. Carbon dioxide (CO2) emissions peaked in the biochemical tank, consistent with rapid oxidation of labile organic carbon. Fluorescence and molecular analyses revealed a shift in dissolved organic matter (DOM) from protein like to more humic and processed molecules, while community assembly remained predominantly deterministic despite greater stochasticity in later stages. The C–P lyase catalytic core was enriched in these units, accompanied by higher phnJ transcript abundance, candidate organophosphonate features, and genomic potential. Together with BES insensitive CH4 formation in independent microcosms, these observations supported C–P lyase mediated organophosphonate utilization as a contributing pathway to local CH4 formation. Integrated evidence indicated that DOM stabilization, deterministic community filtering, potential succinate mediated cross feeding, and phosphonate scavenging jointly shaped this process. These findings show that advanced treatment units are not CH4 hotspots, but neither are they CH4 inactive zones; process resolved GHG assessments should therefore consider persistent local CH4 generation and its association with substrate restructuring and alternative phosphorus acquisition.

244. 题目: Effects of biochar and chemical fertilizer co-application on soil fertility restoration and rice productivity in reclaimed homestead soils
文章编号: N26092801
期刊: Journal of Soils and Sediments
作者: Jing Ju, Ya-Ting Wang, Shuai Chai, Xian-Long Zhao, Wan-Lu Wang, Wen-Jie Song, Tian-Peng Li, Wei Mao, Hai-Tao Zhao
更新时间: 2026-09-28
摘要: Rural homestead-reclaimed soils are often affected by compacted structure, severe nutrient depletion, and microbial imbalance, which restrict their sustainable use and crop productivity. Biochar and chemical fertilizer co-application may simultaneously improve soil conditions and nutrient supply and retention, offering a promising strategy for fertility restoration. However, whether and how their combined application provides complementary benefits over either input alone remains poorly understood. This study evaluated the complementary effects and potential mechanisms of biochar- chemical fertilizer co-application for restoring soil fertility and enhancing rice productivity in reclaimed homestead soils.

245. 题目: Variation in soil organic carbon fractions during coral island succession: Enhanced mineral association and stability
文章编号: N26092716
期刊: Catena
作者: Xianglong Xi, Libin Wu, Liqiang Xu, Yaguang Nie, Siyu Wang, Xiaodong Liu
更新时间: 2026-09-27
摘要: Ecological succession profoundly influences the dynamics and stabilization of soil organic carbon (SOC). However, the mechanisms governing SOC transformation and stabilization during ecological succession in tropical coral island ecosystems remain poorly understood. This study investigated the effects of ecological succession on the dynamics and stabilization of SOC fractions across coral islands representing different successional stages (Cay stage: bare ground with sparse pioneer herbs; NSZ stage: expanding herbaceous vegetation with scattered shrubs; and Island stage: dense shrub communities with relatively advanced soil development). The results demonstrated that topsoil SOC, total nitrogen (TN), and moisture contents increased significantly with ecological succession, whereas soil pH decreased. The contribution of free particulate organic carbon to the SOC pool declined from 78.90% in the Cay stage to 40.08% in the Island stage, while mineral-associated organic carbon (MaOC) increased from 19.88% to 55.30%, becoming the dominant SOC fraction. Analyses of SOC stabilization indicated that SOC was progressively stabilized through the transformation of particulate organic carbon (POC) into MaOC. During the early stages of succession, POC accumulated rapidly, whereas the rate of MaOC accumulation increased substantially during the later stages. Random forest analysis identified soil moisture, pH, and TN as the primary environmental factors regulating MaOC accumulation. Overall, ecological succession altered soil physicochemical properties and promoted the conversion of POC into MaOC, thereby enhancing the long-term stabilization of SOC in coral island soils. These findings provide new insights into the mechanisms of SOC stabilization during ecological succession and improve our understanding of carbon sequestration and carbon cycling in coral island ecosystems.

246. 题目: Changes in organic matter chemistry of two peat profiles deposited from the permafrost regions of the Altai Mountains, northwestern China
文章编号: N26092715
期刊: Catena
作者: Yan Zhang, Yuyi Tong, Yuangong Liu, Yanli Yang, Chuanyu Gao, Ping Yang, Philip A Meyers
更新时间: 2026-09-27
摘要: Peatlands in northern permafrost regions are significant carbon pools, and bogs and fens form following permafrost thaw could promote carbon (C) loss. However, the extent of decomposition of post-thaw deep peat and C loss potential remains uncertain. Peat organic matter (OM) chemistry is likely to be an important factor affecting C balance, but it remains unclear how changes in the kind of OM deposited in post-thaw peatlands govern long-term C storage and decomposition potential. In this study, peat cores from two different post-thaw sites that developed during the Holocene and the permafrost has completely thawed in the permafrost regions of Xinjiang Altai Mountains in China were studied to identify changes in peat OM bulk chemical stability and to explain their possible controls and decomposition potential. The results show that deep peat decomposition is limited with higher OM chemical recalcitrance dominated by more recalcitrant aromatics. Shifts in hydrothermal conditions and vegetation communities related to permafrost thaw during the early Holocene might have reduced peat OM chemical recalcitrance, and more C in the upper peat has become available to microorganism for organic carbon (OC) decomposition. We demonstrate that the old C stored in deep peat might be significant C stocks with limited decomposition potential, and upper peat might be a major driver of future carbon losses in the post-thaw sites. In addition, site-specific differences in local conditions might contribute to different variations in peat OM chemistry between the two sites. We postulate that peat OM chemistry related to local factors and shifts in historical conditions is an important driver for evaluating the relationship between carbon sink sources and future climate warming in the permafrost peatlands.

247. 题目: Integration of an iron-based electrochemical process with a membrane bioreactor for fouling control and removal of proteins, carbohydrates, and humic substances from pharmaceutical-containing wastewater
文章编号: N26092714
期刊: Journal of Environmental Chemical Engineering
作者: Parisa Farshbaf, Hossein Hazrati, Hamed Ranjbar Fathi, Mohammad Babazadeh
更新时间: 2026-09-27
摘要: Wastewater containing pharmaceutical residues can be difficult to treat because persistent compounds may resist biological removal and the associated organic matrix can promote membrane fouling. This study evaluated a hybrid iron-based electrochemical oxidation membrane bioreactor (EO-MBR) against a standalone MBR. A 3D-printed electrochemical flow cell with iron electrodes was integrated into the recirculation loop of a lab-scale hollow-fiber MBR and operated at 5 V for 30 days. The standalone MBR achieved higher final COD removal (94%) than the EO-MBR (80%), whereas the EO-MBR showed greater BOD₅ reduction (96%) and modified the composition of the residual organic fraction. EO integration also reduced fouling-related biopolymers, including EPS and SMP, and limited TMP development to 15 kPa, approximately half of the MBR value. FTIR and EEM analyses showed reduced proteinaceous, carbohydrate-associated, and humic-like foulant fractions in the EO–MBR, demonstrating decreased accumulation of major foulant-associated organic components under combined electrochemical and iron-mediated conditioning. Microscopy and SVI indicated more compact, settleable sludge flocs during EO-MBR operation. Semi-quantitative LC-MS/MS analysis indicated limited additional attenuation of carbamazepine and metoclopramide after EO integration, suggesting that the primary benefit of EO under the tested conditions was associated with fouling control rather than enhanced micropollutant removal. Overall, iron-based EO-MBR integration enhanced fouling control, improved filtration stability, and altered the fate of biodegradable and refractory organic fractions, offering a promising strategy for advanced treatment of pharmaceutical-containing wastewater.

248. 题目: Soluble organic matter evolution and mineral transformation synergistically drive Cd-Pb-Cu immobilization by magnetized bentonite modified biochar
文章编号: N26092713
期刊: Journal of Environmental Chemical Engineering
作者: Shuzhi Liu, Wei Ding, Tao Cao, Guoqing Zhang, Hongwei Zhang, Jiayu Meng, Qing Zhen, Zengchao Geng
更新时间: 2026-09-27
摘要: The remediation of agricultural soils co-contaminated with multiple heavy metals remains a significant challenge due to complex competitive adsorption dynamics and diverse behaviours of metal ions. To address the limitations of conventional immobilizing agents, this study synthesized a novel magnetic bentonite-modified rice straw biochar via a combined KOH activation and co-pyrolysis strategy (Fe3O4@B-BC) for the targeted remediation of Cd-Pb-Cu co-contaminated soil. Following a 98-day soil incubation, the application of 5 g/kg Fe3O4@B-BC (FB5) significantly reduced the DTPA-extractable fractions of Cd, Cu, and Pb by 47.73%, 55.65%, and 63.56%, respectively, compared with the control. Comprehensive characterization revealed that the immobilization mechanisms involved the formation of an FeOOH shell through Fe⁰ oxidation, potent complexation by abundant oxygen-containing functional groups, and the precipitation of silicate minerals. Structural equation modelling demonstrated that soil pH elevation, organic matter enrichment, and the progressive aromatization of dissolved organic matter were the primary factors reducing heavy metal bioavailability, collectively accounting for 56.9% of the mechanistic contribution. Pot experiments with Brassica rapa confirmed that the FB5 amendment not only effectively suppressed heavy metal translocation into edible tissues but also substantially improved crop agronomic performance, resulting in a 77.21% increase in vitamin C biosynthesis. Consequently, Fe3O4@B-BC exhibited exceptional multimechanistic efficacy in mitigating composite heavy metal contamination, highlighting its potential as an innovative soil amendment for promoting safe agricultural production.

249. 题目: Beyond the black box: Deconvoluting the inherent compounds in biochar phytotoxicity and soil impact
文章编号: N26092712
期刊: Journal of Hazardous Materials
作者: Minyan Wang, Haohao Bian, Junhao Huang, Jiamin Qi, Hao Zhou, Xiaopiao Hu, Nicholas Clarke, Ming Hung Wong, Jin Zhang
更新时间: 2026-09-27
摘要: Biochar can support environmental remediation, but its inherent chemical constituents may also cause phytotoxicity and soil ecological disturbances. Here, biochars produced from kitchen waste (Kit), pig manure sludge (Pms), and rice straw (Ris) at 400 and 600 ℃ were evaluated to identify major chemical risk drivers. Water-extractable inorganic ions, DTPA-extractable metals and As, 16 priority polycyclic aromatic hydrocarbons (PAHs), and dissolved organic matter (DOM) were characterized by ICP-MS, GC-MS, and FT-ICR-MS. Short-term radish bioassays, a 180-day soil incubation, correlation analysis, and structural equation modelling were used to link chemical fingerprints with biological responses. KitBC showed the strongest phytotoxicity, particularly KitBC600 at the 1:20 exposure ratio, where germination rate and germination index decreased to 31.11% and 13.15, respectively. RisBC400 contained the highest total PAH concentration (63.46 mg kg−1), which decreased to 6.57 mg kg−1 at 600 ℃. Across feedstocks, increasing pyrolysis temperature reduced total PAHs by 77.6–89.6% and decreased the number of detected DOM molecular formulas, whereas soluble ions and extractable metals showed feedstock-dependent responses. Na/K salts, extractable Cu, and hydrophobic DOM were identified as major contributors to phytotoxicity and soil ecological responses. These findings demonstrate feedstock- and temperature-dependent chemical risk fingerprints and support targeted screening and management of biochar.

250. 题目: Fulvic acid in humic substances accelerates dissemination of antibiotic resistance via conjugative transfer
文章编号: N26092711
期刊: Journal of Environmental Management
作者: Shuhan Li, Lanjun Wang, Yuanfei Gao, Yuqing Hou, Feifan Ren, Yuhan Ye, Yibo Gao, Lusheng Zhu, Jun Wang, Jinhua Wang
更新时间: 2026-09-27
摘要: Humic substances (HS) are widely used as soil amendments to improve soil fertility and support sustainable agriculture, yet the differential roles of their major fractions, fulvic acid (FA) and humic acid (HA), in plasmid-mediated dissemination of antibiotic resistance genes (ARGs) remain unclear. In this study, Escherichia coli (E. coli) HB101 carrying the RP4 plasmid and E. coli NK5449 were used as donor and recipient, respectively, to compare the effects of HA and FA on ARGs conjugative transfer. Both HA and FA significantly promoted RP4 transfer, with 5 g/L FA increasing conjugative transfer frequency (CTF) by 6.29-fold and regulating conjugation-related genes. Compared with HA, FA caused greater membrane disruption, probably due to its smaller molecular size and higher solubility. FA also induced ROS accumulation, increasing extracellular polymeric substances (EPS)-mediated cell contact. Transcriptomic analysis suggested that FA repressed lipopolysaccharide (LPS) biosynthesis-related pathways and increased ATP supply for conjugation. Partial least squares path modeling (PLS-PM) identified cell contact as the strongest direct driver of CTF, while the SOS response had the highest total effect. Notably, FA application below 40 kg/ha in protected vegetable systems may provide a low-exposure reference for subsequent soil validation to balance agronomic benefits and ARGs dissemination risk. This study reveals the mechanisms by which FA-rich HS facilitate plasmid-mediated ARGs dissemination and highlights FA as a potential risk factor in agricultural applications, offering guidance for the safer use of FA-containing products.

251. 题目: Agroforestry hedges either increase or decrease soil organic carbon stocks depending on the use of plastic mulch in Southern Quebec (Canada)
文章编号: N26092710
期刊: Journal of Environmental Management
作者: Marc-Olivier Martin-Guay, Émilie Maillard, Vincent Poirier, David Rivest
更新时间: 2026-09-27
摘要: Agroforestry hedges (AFH), including windbreaks and riparian buffers, can mitigate climate change and improve agroecosystem resilience. Many studies report positive effects of AFH on soil organic carbon (SOC) stocks, yet outcomes remain variable. The factors controlling SOC dynamics under AFH, particularly management practices, therefore must be better understood. We quantified C stocks in soils (0-20 and 20-50 cm), tree biomass, litter and woody debris across 36 AFH located in Southern Quebec (Canada), and compared them with adjacent croplands. These AFH varied in age (5-46 years), tree composition, soil texture and mulch type (none or limited vs. continuous plastic strip). SOC stability was assessed through physical size fractionation into mineral-associated organic matter (MAOM) and particulate organic matter (POM). Contrary to expectations, SOC stocks in the whole profile (0-50 cm) were slightly lower (−6.4 ± 3.9%; mean ± SE) under AFH compared to adjacent fields, due to losses (−13 ± 4%) in the subsoil. These losses were not observed in more developed AFH, suggesting a gradual recovery over time. In the topsoil, SOC increased (+24 ± 5%) in the absence of continuous plastic strips, but decreased (−12 ± 5%) when strips were present. The labile POM fraction accounted for most SOC accrual under AFH (+67 ± 14% relative to controls without plastic strip in the topsoil), while MAOM declined across all layers. Despite these soil responses, total C stocks increased by 21 ± 7 Mg C ha−1 in AFH, mainly due to tree biomass. Biomass C sequestration peaked at 3.7 Mg C ha−1 yr−1 23 years after plantation. Our results highlight that management practices during AFH establishment can strongly influence SOC dynamics and that plastic mulch may offset potential SOC gains, even though overall C sequestration remains positive due to tree biomass accumulation.

252. 题目: Organic matter driven methane and carbon dioxide enrichment in groundwater systems: Molecular and isotopic evidence
文章编号: N26092709
期刊: Water Research
作者: Shanyi Wu, Yijun Yang, Meng Zhang, Qixiang Wang, Shiyao Liu, Rong Wang, Jiaye Cao, Yao Du, Yanxin Wang
更新时间: 2026-09-27
摘要: Dissolved organic matter (DOM) plays a crucial role in methane (CH4) and carbon dioxide (CO2) enrichment in groundwater systems, but the underlying mechanism regulating CH4 and CO2 dynamics across diverse DOM degradation pathways at molecular-level remains elusive. To fill this knowledge gap, stable carbon isotopes (13C-CH4, 13C-CO2, and 13C-DIC) coupled with DOM optical properties and molecular signatures were employed to elucidate the spatial heterogeneity of groundwater CH4 and CO2 within the alluvial-lacustrine aquifer along the middle reaches of the Yangtze River. Hydrochemical and stable carbon isotopic fingerprints revealed that CH4 and CO2 production is governed by two distinct OM degradation pathways, the fermentation stage and the methanogenic stage. DOM optical properties and molecular signatures further unraveled the unique DOM composition governing the divergence between CH4 and CO2 production pathways. Degradation of labile DOM such as aliphatic compounds fueled early CO2 production at the fermentation stage, and recalcitrant molecules such as polyphenols and highly unsaturated and phenolic compounds with higher NOSC values were more thermodynamically favorable to be utilized, which is conducive to CH4 enrichment when it gradually approaches the methanogenic stage. These findings could enhance the comprehensive understanding between DOM degradation and greenhouse gas emissions from an integrated isotopic and molecular-level perspective, and provide insights into carbon cycling and greenhouse gas emission budgets, thus might be applicable to similar alluvial-lacustrine aquatic environments.

253. 题目: Mechanisms of lithium adsorption on Fe/Mn–modified biochar: A ToF-SIMS and surface complexation modeling study
文章编号: N26092708
期刊: Journal of Hazardous Materials
作者: Yangyang Zhang, Xinyu Han, Jinghe Chen, Bo Zu
更新时间: 2026-09-27
摘要: Lithium contamination from the expanding battery industry is an emerging environmental concern, yet Li adsorption mechanisms on heterogeneous sorbents remain poorly understood. Here, Fe/Mn-modified wheat straw biochars were synthesized at three Fe:Mn ratios. The optimal material, F5M1BC, achieved a Li+ adsorption capacity of 145.2 mg/g, retained 90% uptake over 10 regeneration cycles, and maintained above 85% removal under 20-fold excess competing cations. ToF-SIMS was applied for the first time to lithium adsorption on biochar, coupled with an automated Pearson co-localization protocol screening 130 fragment ions across lateral and depth dimensions. The analysis identified 17 Li-bearing fragments in five binding categories, namely Li–silicate, Li–Mn, Li–Fe, Li–Fe–Mn ternary, and Li–chloride, partitioned between metal oxide and silicate microdomains. Depth profiling resolved a three-layer architecture consisting of a surface metal oxide–hydroxyl domain, an intermediate organic–metal composite domain, and a deep silica-rich interior. A three-site non-electrostatic surface complexation model, with each site defined by a ToF-SIMS depth domain, reproduced pH-edge and isotherm data with fitted pKa values of 2.41, 6.05, and 9.19, linking spatially resolved binding architecture to macroscopic adsorption. Combining automated ToF-SIMS co-localization screening with site-specific surface complexation modeling provides a generalizable strategy for examining adsorption mechanisms on chemically heterogeneous materials.

254. 题目: Topographic drainage impedance is associated with organic matter compositions and mercury partitioning in a montane-alpine ecosystem
文章编号: N26092707
期刊: Environmental Pollution
作者: Xizi Yang, Martin Tsz-Ki Tsui, Xiaoyu Song, Hui Zeng, Dong Ren, Luming Yang, Lin Liu, Wenli Tang, Huan Zhong, Cuijing Zhang, Alex Tat-Shing Chow, Junjian Wang
更新时间: 2026-09-27
摘要: We examined associations among topographic position, organic matter compositions, and methylmercury (MeHg) pools and partitioning in montane-alpine soils. Triplicate 60-cm soil cores were collected at 12 sites along a 1,666–4,503 m elevational transect on the eastern slope of Gongga Mountain, spanning an alluvial plain, an intermontane basin, and ridge-shoulder terrain. A drainage impedance index (DI), calculated from plan curvature and slope, represented potential lateral water convergence relative to downslope drainage. DI was negatively associated with the weight-averaged nominal oxidation state of carbon (NOSC) of water-extractable organic matter (adjusted R2 = 0.31, p = 0.034). NOSC was used as a formula-derived molecular descriptor of detected water-extractable organic matter. For exploratory sample-level comparisons, 21 site-depth analytical units were assigned to operational lower-NOSC (NOSC < −0.2; n = 4) or higher-NOSC (NOSC ≥ −0.2; n = 17) groups. The lower-NOSC group contained a larger median contribution of lipid-like formulas and a smaller contribution of phytochemical-like formulas. Basin surface sites contained larger bulk MeHg pools, while ridge sites had a larger operationally water-extractable share of MeHg. These observations identify DI as a candidate screening covariate for spatial variation in MeHg pools and partitioning. Independent transects with direct hydrologic and redox measurements can test the proposed processes in future studies.

255. 题目: Land use shapes soil organic matter stabilization and chemistry in tropical soils: insights from density fractionation and X-ray photoelectron spectroscopy
文章编号: N26092706
期刊: Environmental Science and Pollution Research
作者: Kiattisak Sonsri, Benjamaporn Janplang, Yutthana Phankamolsil, Ratchadaporn Supruangnet, Napaporn Phankamolsil
更新时间: 2026-09-27
摘要: Although land use influences on soil organic matter (SOM) dynamics are well recognized, stabilization and chemical components of SOM under diverse land uses in tropical soils are not fully understood. Herein, we aimed at investigating SOM stabilization and chemical components across contrasting land uses in tropical soils. Soil samples were collected from seven representative land uses: forest, pasture, corn plantation, sugarcane plantation, cassava plantation, orchard, and abandoned land. SOM was physically isolated into free particulate SOM (fSOM), occluded light SOM (oSOM), weakly bound SOM (wSOM), and strongly bound SOM (sSOM) fractions. The SOM chemical components were characterized using X-ray photoelectron spectroscopy (XPS). Among different land uses, total soil organic carbon (SOC) content was highest in pasture (18.5 g C kg–1 soil), followed by cassava plantation, forest, and orchard. The SOC contents in fSOM (1.26–2.37 g C kg–1 soil), oSOM (0.57–2.33 g C kg–1 soil), and wSOM (1.24–4.52 g C kg–1 soil) fractions were highest under forest. The SOC in sSOM fraction (6.66–10.63 g C kg–1 soil) was higher under pasture and cassava plantation. XPS data showed that aliphatic C was the most predominant C functional group, accounting for the larger C content in bulk soil, fSOM, wSOM, and sSOM fractions. On the opposite, the larger C content in oSOM was attributed to physically protected ether/alcohol C and/or carboxylic C inside soil aggregates. These findings highlight that management practices enhancing aliphatic C-rich organic inputs may be beneficial for improving C sequestration in tropical agricultural landscapes.

256. 题目: Trace 7-ACA exposure compromises NOM removal and relatively enriches β-lactam resistance genes in GAC biofilters
文章编号: N26092705
期刊: Chemical Engineering Journal
作者: Samia Saleem, Lei Xu, Shahid Mehmood, Qingqiang Dou, Nigel J D Graham, Wenzheng Yu
更新时间: 2026-09-27
摘要: Pharmaceutically active compounds, including antibiotics and their intermediates such as 7-aminocephalosporanic acid (7-ACA), pose a dual threat to aquatic systems through chemical contamination and the potential propagation of antimicrobial resistance genes (ARGs). Here, bench-scale granular activated carbon (GAC) biofilters fed with Jingmi River water and amended with 0, 1, or 10 μg/L 7-ACA (one column per dose, without replicate columns) were used to examine how antibiotic-intermediate exposure is associated with natural organic matter (NOM) removal and resistance dynamics. Results showed that biofilter exposure to 10 μg/L 7-ACA decreased DOC removal efficiency from about 67% in the control to around 46%. Although absolute β-lactam ARG copies decreased alongside a marked loss of biomass, the abundance of bla-TEM and bla-CTX-M relative to 16S rRNA genes increased (approximately 4-fold and 1.4-fold, respectively), indicating relative enrichment of resistance determinants through the loss of sensitive populations rather than net gene amplification. intI1 was detected in all biofilms, indicating mobilization potential rather than direct evidence of active horizontal gene transfer. 16S rRNA gene sequencing revealed shifts in biofilm community structure across the gradient, with reduced diversity under high 7-ACA exposure, consistent with stress-driven restructuring and loss of sensitive taxa. Furthermore, flow cytometry showed a decline in bacterial abundance across the gradient in effluents, from roughly 19,000 to 12,000 to 4500 cells mL−1 under nominal 7-ACA exposures of 0, 1 and 10 μg/L respectively. Together, these convergent trends indicate that trace-level 7-ACA exposure can simultaneously compromise DOC removal and reduction of absolute ARGs' copies thus relatively enrich β-lactam resistance determinants relative to total biomass in GAC biofilters, highlighting an under-recognized risk for biological drinking-water treatment.

257. 题目: Uncovering the role of chemically dark dissolved organic matter across sediment–water interface along river-to-ocean continuum
文章编号: N26092704
期刊: Water Research
作者: Zekun Zhang, Ruanhong Cai, Peng Yao, Julian Merder, Julian P Sachs, Christian Lønborg, Chen Zhao, Zhenwei Yan, Junming Zhou, Ding He
更新时间: 2026-09-27
摘要: Benthic-pelagic exchange of dissolved organic matter (DOM) plays a critical role in coastal carbon cycling. Yet conventional ultrahigh-resolution mass spectrometry analyses routinely discard a substantial fraction of unassigned mass peaks, termed dark DOM (DDOM), leaving its contribution to carbon exchange unresolved. Here, we characterized the chemical fingerprints and exchange dynamics of DDOM across the sediment-water interface along the Yangtze River Estuary-to-Ocean continuum. Our results reveal that surface sediments act as a large, selective reservoir for DDOM, containing 8542 unique DDOM features compared to 6969 in the water column, of which 2433 were shared between these compartments. These shared, cross-interface DDOM features accounted for approximately 40% of the DDOM signal intensity in the water-column samples, indicating substantial compositional overlap between sediment and water-column DDOM pools. Isotope-association tracking further identifies distinct biogeochemical patterns: terrestrial- linked DDOM extends farther offshore, whereas 14C-depleted, older-carbon-associated DDOM is preferentially enriched near the mouth of the estuary. Together, these findings demonstrate that DDOM is not analytical noise, but rather a previously underappreciated DOM fraction that provides complementary molecular evidence of connectivity across the sediment–water interface in river-dominated coastal margins.

258. 题目: Evaluating dissolved organic matter and trihalomethanes removal in conventional urban water treatment plants in Indonesia: A performance monitoring approach
文章编号: N26092703
期刊: Chemosphere
作者: Mohamad Rangga Sururi, Mayla Zahra Nugraha, Mila Dirgawati, Muammar Qadafi
更新时间: 2026-09-27
摘要: The presence of natural organic matter (NOM) plays a critical role as disinfection by products (DBPs) precursor in Dago Pakar Unit water treatment plant (WTP). This study aims to assess the potential formation of regulated DBP, trihalomethanes (THMs) influenced by NOM characteristics at the Dago Pakar Unit WTP. The study involved the analysis of physicochemical parameters, spectral NOM characterization, and DBPs formation potential, particularly THMs. The results indicated that the physicochemical parameters of temperature and residual chlorine did not comply with quality standards, while pH, turbidity, and electrical conductivity (EC) remained within acceptable limits. The measurement of chromophoric dissolved organic matter (CDOM), including UV254, UV355, UV250/365 or E2/E3 ratio, and fluorescence dissolved organic matter (FDOM), indicated that the organic compounds were predominantly aromatic, such as humic and fulvic acids, originating from both autochthonous and terrestrial sources. The conventional treatment process successfully removes the humic acid-like by 93.24%, but has no significant effects on other fractions. The formation potential of trihalomethanes-4 (THM4) of raw water was 1457.76 μg/L, and only reduced by only 24% after the treatment process, exceeding the maximum contaminant levels set by USEPA and Indonesia's Ministry of Health Regulation. Rainfall events reduce the THM4 formation in both raw and treated water, but are still higher than USEPA regulations. Based on the findings, conventional treatment could not be used to alter the THM precursor in Dago Pakar WTP.

259. 题目: Mechanistic study of bisphenol A removal from water using Fe and HNO3 co-modified clay-based biochar: Adsorption, in situ pyrolytic degradation, and DFT insights
文章编号: N26092702
期刊: Journal of Hazardous Materials
作者: Chenguang Zhang, Xiaofei Xu, Chuancheng Dongye, Chenglong Yuan, Mengran He, Xiuli Shen, Xincheng Chen, Zhihe Li, Shaoqing Wang
更新时间: 2026-09-27
摘要: Bisphenol A (BPA), a typical endocrine-disrupting pollutant, poses a threat to human health. In this study, an Fe and HNO3 co-modified adsorbent was synthesized through the co-pyrolysis of lignin and spent bleaching clay for BPA removal. The effects of initial pollutant concentration, pH, coexisting substances, and regeneration cycles on adsorption performance were systematically investigated. The results showed that 1 M HNO3 treatment enhanced Fe dispersion, and introduced abundant oxygen-containing functional groups. The Fe/Ads-1N exhibited a maximum theoretical adsorption capacity of 44.94 mg/g for BPA. DFT calculations revealed the formation of stable coordination complexation interactions between the electron-rich phenolic hydroxyl oxygen of BPA and the electron-deficient Fe active sites, as well as the role of oxygen-containing functional groups as excellent hydrogen bond donors/acceptors. After three regeneration cycles, Fe/Ads-1N retained an adsorption capacity of 25.1 mg/g. Furthermore, 49.7 mg/g of phenol and methane-rich gas were recovered during the regeneration process, demonstrating the potential for converting pollutants into resource recovery. Pyrolysis regeneration of spent adsorbents offered higher stability and lower per-run operating costs compared to solvent regeneration. This study provides a viable strategy for the high-value utilization of pyrolysis residues and the efficient removal and recovery of BPA from aqueous systems.

260. 题目: Managing long-term passivation in pyrite-based constructed wetlands for low C/N wastewater: roles of Fe–P precipitation, EPS evolution and microbial succession
文章编号: N26092701
期刊: Journal of Environmental Management
作者: Zhaoyang You, Jinlong Wang, Zibo Yan, YiLin Zhou, YanJun Jing, Su Li, Cong Li, KaiLong Liu
更新时间: 2026-09-27
摘要: Pyrite-based constructed wetlands can enhance autotrophic denitrification in low-C/N wastewater, but progressive mineral coating may impair long-term electron-donor availability at the biofilm–pyrite interface. This study investigated mechanisms associated with the performance of a pyrite-based constructed wetland (Pyrite-CW) during approximately 700 days of operation. During the stable stage (days 100–400), Pyrite-CW achieved a TN removal efficiency of 50.0 ± 3.4% and an average effluent TN concentration of 8.37 mg/L, outperforming coarse sand-CW and quartz sand-CW. After approximately day 550, TN and NO3−-N removal declined to 33.4 ± 3.4% and 28.9 ± 2.2%, respectively, indicating sustained performance deterioration. Controlled batch tests showed that additional and in situ-produced Fe–P phases reduced TN removal by approximately 30–50%, while Fe(OH)3 treatments caused approximately 25% inhibition. Surface characterization and reduced electron transport system activity strongly supported interfacial passivation. EPS shifted from a protein/humic-like-substance-rich matrix to a polysaccharide-enriched structure, and microbial succession was associated with a decline in Sulfurimonas and enrichment of Acidobacteriota and Geothrix. These convergent results provide strong evidence that Fe–P-centered surface passivation was a major pyrite-specific mechanism contributing to declining denitrification. Although hydraulic aging may have contributed at the whole-wetland scale, it cannot explain the treatment-specific inhibition independently reproduced in the controlled batch systems. Phosphorus control, pH buffering, staged substrate design, and combined biochemical and hydraulic diagnostics are recommended for maintaining long-term Pyrite-CW performance.