Science of the Total Environment最新文献

{"title":"Neurobehavioral and neurochemical effects of nano-sized polypropylene accumulation in zebrafish (Danio rerio)","authors":"Minji Kim,&nbsp;Sang Don Kim","doi":"10.1016/j.scitotenv.2025.179404","DOIUrl":"10.1016/j.scitotenv.2025.179404","url":null,"abstract":"<div><div>Plastic pollution, particularly nanoplastics (NPs), is a significant environmental contaminant that poses potential toxicological risks to organisms and ecosystems. Although extensive research has been conducted on the toxicity of NPs, our understanding remains limited, primarily because of the constraints of standardized toxicity studies using polymers of specific sizes and types. To address this gap, we conducted toxicity experiments using directly synthesized polypropylene nanoparticles (PP-NPs) in zebrafish (<em>Danio rerio</em>). The presence of PP-NPs in the zebrafish brain was confirmed using pyrolysis gas chromatography–mass spectrometry (Py-GC/MS) and bio-transmission electron microscopy (bio-TEM). The accumulation of PP-NPs in the brain of <em>D. rerio</em> led to neurotoxicity, manifested as reduced motility and aggressiveness. Altered neurotransmitter levels and neural activity associated with behavior further supported these findings. This study suggests that environmental plastic pollutants may accumulate in the brain and cause neurotoxicity in organisms, emphasizing the need for appropriate management of these substances.</div></div>","PeriodicalId":422,"journal":{"name":"Science of the Total Environment","volume":"977 ","pages":"Article 179404"},"PeriodicalIF":8.2,"publicationDate":"2025-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing anthropogenic contributions and uncovering inter-regional periodic patterns of ground ozone with high-resolution predictions in 2015–2019 across China","authors":"Junshun Wang ,&nbsp;Jin Dong ,&nbsp;Runkui Li ,&nbsp;Xiaoping Zhang ,&nbsp;Qun Xu ,&nbsp;Xianfeng Song","doi":"10.1016/j.scitotenv.2025.179360","DOIUrl":"10.1016/j.scitotenv.2025.179360","url":null,"abstract":"<div><div>Owing to the strong spatiotemporal variability of ozone and the complexity of its photochemical reactions, it is urgent but difficult to accurately predict the high-resolution distribution of ozone and quantify the effects of anthropogenic drivers. In this study, we employed a random forest model to predict maximum daily 8-hour average ozone concentrations (MDA8 O₃) at a high resolution of 1 km × 1 km across China from 2015 to 2019. The model's performance was validated using three approaches: sample-based, site-based, and year-based, yielding R-squared values of 0.87, 0.85, and 0.81, respectively, and demonstrating superior accuracy compared to previous studies. Our predictions revealed that Central China experienced the most rapid increase in ozone, with some areas exceeding 6 μg/m³/year, surpassing even the economically developed regions of Eastern China, as identified by Sen's slope and the seasonal Mann-Kendall test. Through high-resolution predictions, we uncovered stable inter-regional periodic patterns of high ozone concentrations across four seasons. By controlling for meteorological variables, we also quantified anthropogenic contributions to the changes in ground-level ozone in 2015–2019, which ranged from −12.18 to 43.71 μg/m³ annually, thereby driving the rapid increase in ozone concentrations over Central China. The high-resolution ozone datasets and the identification of inter-regional periodic patterns offer valuable insights for large-scale ozone studies and provide cost-effective strategies for ozone monitoring and control.</div></div>","PeriodicalId":422,"journal":{"name":"Science of the Total Environment","volume":"977 ","pages":"Article 179360"},"PeriodicalIF":8.2,"publicationDate":"2025-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of non-degradable and degradable microplastics on the bioavailability of per- and polyfluoroalkyl substance in mice: Mechanism exploration","authors":"Pengfei Zhou ,&nbsp;Yi Kong ,&nbsp;Dengke Zhang ,&nbsp;Albert Juhasz ,&nbsp;Qian Zhang ,&nbsp;Xinyi Cui","doi":"10.1016/j.scitotenv.2025.179381","DOIUrl":"10.1016/j.scitotenv.2025.179381","url":null,"abstract":"<div><div>Per- and polyfluorinated alkyl substances (PFAS) contamination in drinking water and their associated health risks have received extensive global attention. Microplastics (MPs), which commonly coexist with PFAS in the daily diet, remain poorly understood in terms of their effects on PFAS bioavailability. Here, we investigated the effect of non-biodegradable (PS) and biodegradable (PBS) MPs on PFAS bioavailability using a mouse model, with PFAS level in drinking water being at 20 μg/L. High-dose dietary MPs (50 mg/g) significantly increased PFAS bioavailability, especially for PS co-exposure (29.2 ± 5.09 % vs 19.4 ± 3.66 % in control, <em>p</em> &lt; 0.05), while reducing fecal excretion by 0.34 and 0.31-fold (<em>p</em> &lt; 0.05). Mechanistic studies showed that high-dose PS significantly (<em>p</em> &lt; 0.05) increased mouse serum albumin concentrations, which were closely related with the <em>in vivo</em> absorption of PFAS. Both PS and PBS downregulated the expression of efflux proteins (Mrp2 and Mrp4) by 0.10–0.22 fold, thereby increasing PFAS bioavailability. Molecular docking further showed that legacy PFASs (PFOA and PFOS) exhibited higher binding affinities to transport-related proteins than emerging alternatives (HFPO-TA and 6:2 FTSA), explaining their greater susceptibility to MPs co-exposure. These findings provide novel mechanistic insights into the modulation of PFAS bioavailability by co-exposure of MPs. While high MP doses were used to elucidate the mechanism, future studies using environmentally relevant exposure levels are necessary to assess the health risks of PFAS-MP co-exposure and support science-based risk management.</div></div>","PeriodicalId":422,"journal":{"name":"Science of the Total Environment","volume":"977 ","pages":"Article 179381"},"PeriodicalIF":8.2,"publicationDate":"2025-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transforming syenite through alkaline-hydrothermal processes: A sustainable strategy to overcome potassic fertilizer shortages in tropical regions","authors":"Aaron Mbissik ,&nbsp;Abdellatif Elghali ,&nbsp;Otmane Raji ,&nbsp;Jean-Louis Bodinier","doi":"10.1016/j.scitotenv.2025.179387","DOIUrl":"10.1016/j.scitotenv.2025.179387","url":null,"abstract":"<div><div>Silicate rocks contribute to soil health and crop productivity, but their nutrient release is often slow. This study evaluates alkaline hydrothermal treatment effect on potassium (K) and multi-nutrient (phosphorus (P), calcium (Ca), magnesium (Mg), sulfur (S), and silicon (Si)) availability from syenite rock. Powdered raw and CaO – KOH materials, hydrothermally treated using a design of experiments (DOE) approach were characterized. Along with petrographic characterization, analytical techniques such as X-ray fluorescence (XRF), X-ray diffraction (XRD), Quantitative Evaluation of Minerals by Scanning Electron Microscopy (QEMSCAN), electron probe microanalysis (EPMA), and Fourier transform infrared spectroscopy (FTIR) were employed. In addition, powdered syenite underwent a sequential leaching (1, 24, 194, and 624 h) in deionized water and the leachate was analyzed by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). The results revealed that hydrothermal treatment induced significant mineralogical, chemical, and structural changes, with KOH-treated materials releasing up to 1631 mg/L of K after 26 days. Nevertheless, altered orthoclase remained the dominant K-feldspar (80–90 wt%), while new Ca- and K-bearing phases formed. Regardless of the additive, treated samples released 3 to 69 times more nutrients than raw material (except Mg). However, nutrient dissolution followed a power function with a low rate (0.03–0.9), indicating slow but sustained nutrient availability. The study also revealed antagonistic interaction parameters that may inhibit nutrient release, highlighting key mechanisms of rock weathering. This insight facilitates an 8 % increase in K-release from 7 to 1.5 h of treatment. Therefore, powdered syenite could be a nutrient reservoir and buffer for acidic soils.</div></div>","PeriodicalId":422,"journal":{"name":"Science of the Total Environment","volume":"977 ","pages":"Article 179387"},"PeriodicalIF":8.2,"publicationDate":"2025-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nitrous oxide emissions from production, storage and application of nitrogen enriched organic fertilizer","authors":"Magnus Nyvold ,&nbsp;Peter Dörsch","doi":"10.1016/j.scitotenv.2025.179375","DOIUrl":"10.1016/j.scitotenv.2025.179375","url":null,"abstract":"<div><div>Plasma-based nitrogen (N) enrichment of organic fertilizers can improve agricultural resource efficiency and reduce fertilizer-related greenhouse gas (GHG) emissions. The method uses an electrically generated air plasma to produce reactive N that is absorbed by the organic fertilizer as nitrate (NO₃⁻) and nitrite (NO₂⁻). The enrichment process reduces the pH of the substrate, which reduces ammonia volatilization and inhibits microbial activity, which effectively prevents methane (CH₄) formation and denitrification during storage. However, the elevated content of reactive N increases the risk of chemical and microbial nitrous oxide (N₂O) formation. In this work, we determined a combined N₂O emission factor for the production, storage and field application of nitrogen enriched organic fertilizer to better assess its overall impact on fertilizer-related GHG emission. The N enriched organic fertilizer was shown to emit significantly more N₂O (1.8 % ± 0.48 % of total N) compared to the standard figure for untreated cow manure (1.0 % of total N), likely originating from chemical interactions of NO₂⁻ with organic compounds in the substrate and the soil. Despite the elevated N₂O emissions, the reduction in overall GHG was estimated to 72 ± 5.2 kgCO₂eq ton⁻¹ based on the Tier 2 methodology devised by the IPCC. A clear link was established between the NO₂⁻ content and N₂O emissions and a lower NO₂⁻ concentration was shown to reduce overall N₂O emissions by 45 %. Controlling the NO₂⁻ content is therefore a viable strategy to mitigate the N₂O emissions associated with nitrogen enriched organic fertilizers.</div></div>","PeriodicalId":422,"journal":{"name":"Science of the Total Environment","volume":"977 ","pages":"Article 179375"},"PeriodicalIF":8.2,"publicationDate":"2025-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Frequent water table depth fluctuations due to warm-dry conditions can significantly trigger carbon emissions from coastal salt marshes","authors":"Shuzhen Li ,&nbsp;Qiang Liu ,&nbsp;Liqiao Liang ,&nbsp;Jialiang Zhou ,&nbsp;Tao Sun ,&nbsp;Xuan Wang","doi":"10.1016/j.scitotenv.2025.179372","DOIUrl":"10.1016/j.scitotenv.2025.179372","url":null,"abstract":"<div><div>Coastal salt marshes are crucial for blue carbon storage, but their carbon emission patterns are uncertain due to frequent fluctuations in water table depth (WTD). This uncertainty is caused by the simultaneous impacts of global warming and rising sea levels. This study assessed carbon emission patterns in the Yellow River Delta under different hydrological fluctuation modes (high fluctuation of WTD scenario (HF-WTD) and low fluctuation of WTD scenario (LF-WTD)) and hydrothermal conditions through a 3-year in-situ observational experiment. The region is typically impacted by climatic warming and drying. Results showed that: (<em>i</em>) Intra-annual WTD fluctuations promote CO₂ emission flux, but they are not significantly related to the rising or falling state. On the other hand, methane (CH₄) emission flux are dominated by WTD that are more favourable when WTD continues to rise. (<em>ii</em>) The transition point for carbon emission flux with respect to WTD is between −51 cm and −54 cm, and is not affected by the fluctuation pattern of the WTD. (<em>iii</em>) CO₂ is more sensitive to temperature when the WTD fluctuates violently and is high, while CH₄ is more sensitive to temperature when the WTD is stable and low and the temperature is &lt;17.71 °C. (<em>iv</em>) In the scenario of high-frequency WTD, the variation in WTD, combined with the sharp temperature change, contributes to the peak of CO₂ emission flux. In contrast, in the low-frequency WTD scenario, WTD fluctuations, coupled with extreme temperature fluctuations, contribute to the peak of CH₄ emission flux. The conclusions suggest that the high and frequently fluctuating WTD caused by climate warming and drying, as well as rising sea levels, will significantly increase CO₂ emission flux from coastal salt marsh wetlands. This increase in emission flux will be detrimental to the blue carbon function of coastal wetlands.</div></div>","PeriodicalId":422,"journal":{"name":"Science of the Total Environment","volume":"977 ","pages":"Article 179372"},"PeriodicalIF":8.2,"publicationDate":"2025-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sustainable environmental remediation with bast fiber crops: Phytoremediation potential and resource management","authors":"Muzammal Rehman ,&nbsp;Dengjie Luo ,&nbsp;Jiao Pan,&nbsp;Samavia Mubeen,&nbsp;Shan Cao,&nbsp;Wajid Saeed,&nbsp;Peng Chen","doi":"10.1016/j.scitotenv.2025.179403","DOIUrl":"10.1016/j.scitotenv.2025.179403","url":null,"abstract":"<div><div>With the rapid growth of industry and increasing population pressure, environmental pollution has become a serious issue, causing ecosystem disruption and posing significant risks to human health. Consequently, there is a growing need to explore sustainable resources for environmental protection. Present study focuses on multipurpose bast fiber crops, including kenaf, hemp, ramie, jute, and flax, which are known for their environmental benefits. A comprehensive literature review was conducted, using keywords such as bast fiber crops, sustainable environmental remediation, and phytoremediation. This review examines the environmental benefits of bast fiber crops particularly their role in carbon sequestration, desertification mitigation, atmospheric purification, and utilization of problematic lands. Bast fiber plants offer potential for phytoremediation, aiding in the restoration of polluted soils and wastewater. The selected bast fiber crops were chosen based on their widespread cultivation, environmental resilience, and potential contributions to eco-friendly solutions. This review highlights the key results, emphasizing that these crops provide sustainable substitutes for land rehabilitation, climate change mitigation, and the promotion of green bioenergy, contributing to a more sustainable and healthier environment.</div></div>","PeriodicalId":422,"journal":{"name":"Science of the Total Environment","volume":"977 ","pages":"Article 179403"},"PeriodicalIF":8.2,"publicationDate":"2025-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prevalence of cardiovascular disease risk factors associated with residential natural hazard risk","authors":"Kaitlyn G. Lawrence ,&nbsp;Marina R. Sweeney ,&nbsp;Emily J. Werder ,&nbsp;Casey Zuzak ,&nbsp;Melanie Gall ,&nbsp;Christopher T. Emrich ,&nbsp;Ian D. Buller ,&nbsp;W. Braxton Jackson II ,&nbsp;Dazhe Chen ,&nbsp;Kate E. Christenbury ,&nbsp;Lawrence S. Engel ,&nbsp;Dale P. Sandler","doi":"10.1016/j.scitotenv.2025.179335","DOIUrl":"10.1016/j.scitotenv.2025.179335","url":null,"abstract":"<div><h3>Background</h3><div>Specific natural hazards are associated with increased chronic disease risk. Less is known about the impact of living in regions with elevated natural hazards risk.</div></div><div><h3>Objective</h3><div>We evaluated cross-sectional associations between predicted residential natural hazard risk and CVD-related risk factors.</div></div><div><h3>Methods</h3><div>We used data from the Gulf Long-term Follow-up Study, a prospective cohort enrolled following the <em>Deepwater Horizon</em> disaster (<em>N</em> = 32,608). We evaluated diabetes prevalence among 29,714 participants who provided enrollment data on self-reported physician diagnosis of diabetes. In separate analyses, we evaluated obesity and hypertension using data from 10,727 home visit participants with measured height, weight, and blood pressure. We linked geocoded residential enrollment and home visit addresses to the National Risk Index (NRI, 1960–2020), a monetized risk score that quantifies overall and hazard-specific risk at the census-tract level. Modified Poisson regression estimated prevalence ratios (PRs) and 95 % confidence intervals (CIs) for associations between quartiles of overall and natural hazard-specific risks and prevalence of diabetes, hypertension (systolic/diastolic blood pressure ≥ 140/90 mmHg or antihypertensive medication use), and obesity (BMI ≥ 30.0 kg/m²).</div></div><div><h3>Results</h3><div>The highest quartile of overall NRI was associated with hypertension (Q4 vs. Q1 PR:1.16[1.09,1.24]) but not diabetes or obesity. All quartiles of hurricane risk were associated with higher diabetes prevalence (PR1.33 to 1.36). Increasing quartiles of heatwave risk were associated with increasing prevalence of diabetes, hypertension, and obesity, with PRs 1.23[1.09,1.38], 1.12[1.04,1.19] and 1.09[1.03,1.16] for Q4 vs. Q1, respectively.</div></div><div><h3>Conclusion</h3><div>Residing in areas prone to natural disasters is associated with higher prevalence of key cardiovascular disease risk factors.</div></div>","PeriodicalId":422,"journal":{"name":"Science of the Total Environment","volume":"977 ","pages":"Article 179335"},"PeriodicalIF":8.2,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143815842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multigenerational toxicity effects and impact of antibiotics exposed to duckweed, Lemna minor","authors":"Ali Alfarsi ,&nbsp;Gebremeskel M. Weird ,&nbsp;Anupama Kumar ,&nbsp;Dayanthi Nugegoda","doi":"10.1016/j.scitotenv.2025.179324","DOIUrl":"10.1016/j.scitotenv.2025.179324","url":null,"abstract":"<div><div>The escalating presence of antibiotics in aquatic ecosystems poses substantial risks to public health and ecosystem stability. The objective of this study was to examine the effects of three common antibiotics—ciprofloxacin (CIP), erythromycin (ERY), and sulfamethoxazole (SMX)—on the growth and physiology of <em>Lemna minor</em> (<em>L. minor</em>) across three generations (parental (F0), first filial (F1), and second filial (F2)). Specifically, the research aimed to determine how these antibiotics influence frond number, frond area, root area, and photosynthetic pigment content in L. <em>minor</em>. Higher concentrations of CIP (50 μg/L, 250 μg/L, and 1250 μg/L) significantly decreased frond numbers (F2 &gt; F1 &gt; F0), while ERY exhibited the opposite trend, and SMX displayed adaptation in F2. ERY increased frond area at a lower concentration (10 μg/L), while high concentrations of CIP (250 μg/L and 1250 μg/L) and lower concentrations of SMX (10 μg/L and 50 μg/L) reduced it. CIP displayed a biphasic response on root growth, with 10 μg/L decreasing root area by 760 μm² and 50 μg/L and 1250 μg/L, increasing it by 2480 μm² and 2300 μm², respectively. ERY consistently inhibited root growth. The F1 generation showed the most pronounced reduction in green area, particularly under higher CIP concentrations (1250 μg/L). Chlorophyll A (Chl A) and carotenoid contents were resilient to antibiotic stress, while Chlorophyll B (Chl B) exhibited generation-specific responses. This study highlights the need for continued monitoring of antibiotics in aquatic systems and calls for further research on the long-term impacts of antibiotics on aquatic plants and ecosystems.</div></div>","PeriodicalId":422,"journal":{"name":"Science of the Total Environment","volume":"977 ","pages":"Article 179324"},"PeriodicalIF":8.2,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143815920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of carbon dioxide and methane emission characteristic across Heihe River, China","authors":"Wenhan Hu ,&nbsp;Zhiheng Du ,&nbsp;Lei Wang ,&nbsp;Fangping Yan ,&nbsp;Chuntan Han ,&nbsp;Xiqiang Wang ,&nbsp;Changlian Tao ,&nbsp;Jingfeng Liu","doi":"10.1016/j.scitotenv.2025.179175","DOIUrl":"10.1016/j.scitotenv.2025.179175","url":null,"abstract":"<div><div>Rivers are major sources of methane (CH₄) and carbon dioxide (CO₂) emissions into the atmosphere. However, limited research on CH₄ and CO₂ fluxes and production mechanisms in high-altitude and arid-region rivers constrains a comprehensive understanding of riverine carbon cycle. Heihe River is the second- largest inland basin in China, which originates from the Tibetan Plateau and flows through the arid regions of northwestern China. This study focused on CH₄ and CO₂ emissions along the Heihe River using the headspace technique and a gas chromatograph method. A total of 31 sampling sites were selected along the upstream and downstream stretches of the Heihe River, with 18 sites from the upstream and 13 from the downstream. The results indicate that the Heihe River is the sources of both CH₄ and CO₂ emissions, with higher concentrations and fluxes in the downstream arid region. The average diffusion fluxes of CH₄ and CO₂ in the downstream region are 80.1 μmol·m⁻²·d⁻¹ and 63.6 mmol·m⁻²·d⁻¹, respectively, while they are 35.9 μmol·m⁻²·d⁻¹ and 31.1 mmol·m⁻²·d⁻¹ in the upstream region. CH₄ and CO₂ fluxes in the upstream region were primarily controlled by the physical and chemical parameters (salinity, conductivity, air temperature, pH) and groundwater recharge (²²²Rn), while downstream emissions were influenced by DIC (Dissolved Inorganic Carbon) concentration and groundwater recharge. CH₄ primarily originates from thermogenic sources (δ¹³C-CH₄ &gt; −50 ‰) in the upstream region, while CO₂ was primarily derived from atmospheric input and CH₄ oxidation (α_c &lt; 1.04). In contrast, CH₄ was produced via acetoclastic methanogenesis (1.04 &lt;α_c &lt; 1.06) and anthropogenic activities in the downstream region, while CO₂ sources were influenced by both anthropogenic activities and CH₄ oxidation. This study has enhanced our understanding of the carbon cycle in inland rivers of arid regions through the analysis of CH₄ and CO₂ fluxes and production mechanisms along the Heihe River.</div></div>","PeriodicalId":422,"journal":{"name":"Science of the Total Environment","volume":"977 ","pages":"Article 179175"},"PeriodicalIF":8.2,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143815921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}