Journal of contaminant hydrology最新文献

{"title":"Unraveling the adsorption mechanisms of greenhouse gases on microporous MAF-4 nanoparticles using a statistical physics approach","authors":"E.A. Elghmaz ,&nbsp;Ghada M. Alnafesah ,&nbsp;Mohammed Alissa ,&nbsp;Khalil ur Rehman ,&nbsp;Abdullah Alghamdi ,&nbsp;Suad A. Alghamdi ,&nbsp;Abdulkarim S. Binshaya ,&nbsp;Ghfren S. Aloraini ,&nbsp;Amira K. Hajri ,&nbsp;Adil Abalkhail","doi":"10.1016/j.jconhyd.2026.104850","DOIUrl":"10.1016/j.jconhyd.2026.104850","url":null,"abstract":"<div><div>The continuing struggle to reduce greenhouse gas emissions continues to be one of the most crucial obstacles in achieving both energy efficiency and sustainable, long-term environmental practices. Microporous metal azolate framework-4 nanoparticles (MAF-4 NPs) have emerged as attractive adsorbent materials with their large surface area, adjustable pore architecture, and high chemical stability. Herein we present a green and rapid synthesis of ultramicroporous MAF-4 nanoparticles via the production of no organic solvents through the use of minimal external heating. The resulting MAF-4 NPs (particle size ≥70 nm) have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and nitrogen physisorption analysis and demonstrate a high BET surface area of 1796 m³/g, a total pore volume of 0.75 cm³/g, and ultramicropores predominantly occurring at an average pore diameter of 0.62 nm. A number of gas adsorption behaviors have been experimentally evaluated for four different gases (CO₂, SF₆, CH₄, and N₂) and are subsequently explained using a multilayer adsorption model based on statistical physics that has recently been developed for porous metal-organic frameworks. This combination of theoretical and experimental information provides a greater understanding of how adsorption occurs within porous metal-organic frameworks. The results indicate that gas molecules (at low temperatures) are unaligned, but at higher temperatures they have primarily parallel arrangements and are able to form many layers (multilayer arrangements). The average number of adsorbed gas molecules on an active site range from 0.51 to 1.92 for each different type of gas and temperature combination, and the total number of layers varies from 1.2 to 8.0. Energy of adsorption indicates strong attractive forces for the initial layer of adsorbing molecules and a decrease in attraction for subsequent layers of adsorbing molecules, with values between 2.64 and 8.42 kJ/mol indicating the adsorptive forces are due to physisorption with significant contributions from van der Waals and London dispersion forces. Using thermodynamic evaluations of internal energy and Gibbs' free energy to estimate the spontaneity and exothermicity of the adsorption process shows that at low temperatures there is more disorder among the molecules (higher entropy) than at higher temperatures when the number of adsorbate molecules reaches saturation. This indicates that MAF-4 nanoparticles will be energy-efficient, selective, and regenerable when used for CO₂ and SF₆ capture and have significant capability for scale-up and increased capacity of these adsorbates.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104850"},"PeriodicalIF":4.4,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146010544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Long term rebound and transport of perfluorinated sulfonic acids (PFSAs) in the vadose zone following flushing","authors":"Charles E. Schaefer ,&nbsp;Graig M. Lavorgna ,&nbsp;David R. Lippincott ,&nbsp;Shilai Hao ,&nbsp;J. Conrad Pritchard ,&nbsp;Christopher P. Higgins","doi":"10.1016/j.jconhyd.2026.104848","DOIUrl":"10.1016/j.jconhyd.2026.104848","url":null,"abstract":"<div><div>Increases in perfluorinated sulfonic acid (PFSA) porewater concentrations over a 35 month duration following in situ flushing were monitored at an aqueous film-forming foam (AFFF) site using porous cup suction lysimeters within a highly instrumented test cell. Results provided evidence that perfluorooctane sulfonate (PFOS) slow desorption kinetics contributed to slow contaminant rebound in measured porewater concentrations. PFSAs in the shallow (0.23 m depth) highly PFSA-impacted soils migrated downward during the monitored post-flushing period, with short-chained PFSAs migrating more rapidly in porewater than long-chained PFSAs. Following flushing, apparent equilibrium porewater concentrations at a depth of 0.61 m below ground surface were attained within two months for perfluoropentane sulfonate (PFPeS), between 2 and 20 months for perfluorohexane sulfonate (PFHxS), and 25 months for PFOS. For PFPeS and PFHxS, apparent steady-state rebound concentrations (to 38% of their pre-flushing baseline levels, with no increasing or decreasing trend over time subsequently observed) were reasonably predicted based on an equilibrium model. PFOS rebound and ultimately vertical migration were highly impacted by non-equilibrium soil desorption. Excavation of elevated PFSAs in surface soils had no impact on PFSA porewater concentrations 0.38 m below the excavation over a 1.2 year post-excavation monitoring period. Together, these long-term rebound data highlight the potential importance of mass transfer-controlled processes for PFOS leaching, and suggest that removal of elevated PFSAs in surface soils may take years until PFSA discharges to groundwater are diminished.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104848"},"PeriodicalIF":4.4,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145966331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Anthropogenically-induced saline wetland recharge drives denitrification: Implications for nitrate attenuation in semi-arid aquifer–wetland systems","authors":"D. Sanz ,&nbsp;D. Salcedo ,&nbsp;B. Toledo ,&nbsp;I. Dountcheva ,&nbsp;R. Margalef-Martí ,&nbsp;N. Otero ,&nbsp;A. Soler ,&nbsp;J.J. Gómez-Alday","doi":"10.1016/j.jconhyd.2026.104840","DOIUrl":"10.1016/j.jconhyd.2026.104840","url":null,"abstract":"<div><div>Saline wetlands are highly sensitive to anthropogenic pressures, particularly in semi-arid regions where groundwater abstraction, land use changes, and climate variability modify their hydrogeological functioning. This study focuses on the Tirez and Peñahueca hypersaline wetlands (Central Spain), which have undergone a shift from natural groundwater discharge zones to induced recharge areas due to intensive irrigation. Declining piezometric levels have reversed the hydraulic gradient between the aquifer and the wetlands, resulting in recharge conditions. A multidisciplinary approach combining hydrochemistry, (including historical monitoring data), multi-isotopic characterization (N, O, C, S), and geophysical (ERT) techniques was applied to assess groundwater quality evolution and nitrate attenuation processes. Results show a significant increase in groundwater salinity and nitrate concentrations over the past five decades, with NO₃⁻ levels reaching up to 245 mg/L. Average nitrate concentrations increased from ∼25 mg/L in the 1990s to over 200 mg/L in 2019–2021. Isotopic signatures indicate multiple nitrate sources, including manure, organic soil nitrogen, and synthetic fertilizers. A coupled increase of δ¹⁵N–NO₃⁻ values ranging from +5.1 ‰ to +44 ‰ and δ¹⁸O–NO₃⁻ from +3 ‰ to +23 ‰, along with δ³⁴S–SO₄²⁻ values between +16 ‰ and + 18 ‰ and δ¹³C–DIC from −12 ‰ to −4 ‰, suggest that heterotrophic denitrification is the main attenuation process. Electrical resistivity profiles reveal density-driven flow from the saline wetland water into the underlying aquifer, facilitating the transport of dissolved organic carbon and creating redox gradients favorable for denitrification. Maximum denitrification rates of up to 73% were estimated using literature isotopic fractionation values. Understanding the coupled hydrological and biogeochemical dynamics of saline wetland–aquifer systems is essential for developing sustainable groundwater management strategies in vulnerable arid and semi-arid regions.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104840"},"PeriodicalIF":4.4,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145966315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 time-varying contaminant discharge rates using a data-driven Transformer model","authors":"Yaning Xu ,&nbsp;Wenxi Lu ,&nbsp;Liuzhi Zhu ,&nbsp;Qingchun Yang","doi":"10.1016/j.jconhyd.2026.104847","DOIUrl":"10.1016/j.jconhyd.2026.104847","url":null,"abstract":"<div><div>The identification of groundwater contamination sources (IGCS) is a critical prerequisite for the development of contamination remediation strategies and is vital for safeguarding groundwater resources. However, the recurrent neural networks (RNNs) previously applied to address IGCS have limitations due to their requirement for stepwise processing of data and inability to handle parallel processing, which restrict both accuracy and efficiency. This study applies the Transformer model to directly identify groundwater contamination source characteristics. The self-attention mechanism of the Transformer model effectively captures long-range dependencies in input data, overcoming the limitations of step-by-step data processing and supporting parallel processing of sequential information. This advantage allows the Transformer model to capture the dynamic changes in contamination source characteristics (e.g., contaminant discharge rates) across different time steps, resulting in more accurate IGCS. A hypothetical case study is conducted to compare the performance of data-driven methods (Transformer and MLP inverse mapping models) with surrogate-assisted physics-based methods (optimization and data assimilation methods), for identifying contamination source characteristics. The results indicate that the Transformer model performs better in terms of identification accuracy. The data assimilation method provides satisfactory results with a lower computational burden, making it more suitable for scenarios with strict time requirements. The optimization method requires more computational time and produces less accurate identification results compared to the other three methods.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104847"},"PeriodicalIF":4.4,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145966236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Laboratory modeling of microbial and chemical clay minerals transformations of upper aquifer soils under intensive technogenic impact","authors":"Grigory Artemiev ,&nbsp;Nadezhda Popova ,&nbsp;Alexey Averin ,&nbsp;Anatoly Boguslavsky ,&nbsp;Ivan Morozov ,&nbsp;Olga Zakusina ,&nbsp;Victoria Krupskaya ,&nbsp;Alexey Safonov","doi":"10.1016/j.jconhyd.2026.104845","DOIUrl":"10.1016/j.jconhyd.2026.104845","url":null,"abstract":"<div><div>Storage of nitrogen‑sulfuric acid waste from uranium ore mining and processing enterprises in sludge ponds leads to groundwater contamination by soluble components with degradation of impervious barriers. This results in a significant alteration of the geochemical environment and the mineral composition of rocks, as well as creates risks of soluble toxic components from waste entering water intakes and open hydrographic networks. Laboratory modeling of biofouling processes and subsequent alterations in soil composition from upper aquifer adjacent to the sludge repository of the Angarsk Electrolysis Chemical Plant (Angarsk, Russia) was conducted in this study. The investigation established that anthropogenic impacts resulting from elevated concentrations of nitrates, sulfates, ammonium, and bicarbonates significantly modify both the mineralogical and microbial composition of soils, consequently influencing their biogeochemical transformation characteristics. Under technogenic pollution conditions, microbial processes promote the development of more densely structured biofilms while simultaneously impeding iron reduction processes that normally facilitate more profound mineralogical alterations. The transformation of clay mineral composition plays a pivotal role in biofouling dynamics and governs subsequent mineral modification pathways. Microbial-mediated processes can induce structural reorganization of smectite minerals into tobelite-like configurations through two principal mechanisms: biologically facilitated iron dissolution and ammonium saturation of interlayer spaces resulting from dissimilatory nitrate reduction and subsequent ammonification processes.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104845"},"PeriodicalIF":4.4,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Vegetation type dominates slope-scale material loss under extreme rainfall: Nonlinear responses revealed by machine learning","authors":"Aipu Wu ,&nbsp;Chunzi Ma ,&nbsp;Shouliang Huo ,&nbsp;Tianxiao Li ,&nbsp;Qiang Fu","doi":"10.1016/j.jconhyd.2026.104846","DOIUrl":"10.1016/j.jconhyd.2026.104846","url":null,"abstract":"<div><div>Extreme rainfall events may be intensified by climate change. These events pose significant threats to slope-scale soil erosion and non-point source (NPS) pollution in mountainous agricultural watersheds. In this study, seven years (2014–2020) of field observations from four runoff plots with different vegetation (farmland vs. shrubland) and slope types (steep vs. gentle) within the Miyun Reservoir watershed, northern China, were used to investigate material losses under contrasting rainfall patterns. Losses of soil, total nitrogen (TN), and total phosphorus (TP), along with runoff and chemical oxygen demand (COD), were quantified using a novel machine learning framework that integrated a Random Forest (RF) model with Sequential Backward Selection (SBS) and relative importance (RI) analyses. A total of 61 runoff-generating rainfall events, that included 10 rainfall events classified as extreme on the basis of the rainfall depth and 30-min maximum intensity (I₃₀), were analyzed. Extreme rainfall accounted for only 16.4 % of the runoff events but contributed to 41.9 % in soil loss and 49.2 % in COD. Farmland was particularly vulnerable, and it had 2–5 times the losses of shrubland under extreme rainfall events. The vegetation type and 60-min rainfall intensity (I₆₀) emerged as dominant factors that controlled losses under extreme rainfall events, while vegetation type and rainfall intensity governed material losses under normal rainfall events. A partial dependence plot (PDP) analysis revealed a nonlinear response of the material loss to I₃₀, with sharp increases between 30 and 40 mm·h⁻¹. This result indicated critical material loss thresholds. These results revealed the dominant role of the vegetation type in controlling material loss at the slope scale and confirmed the potential of machine learning to explain complex hydrological processes.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104846"},"PeriodicalIF":4.4,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Adsorption and mechanism of magnetically modified industrial hemp straw biochar on microplastics in aqueous solution","authors":"Xi Jiang ,&nbsp;Youxi Cai ,&nbsp;Hanwen Deng ,&nbsp;Xiaolei Li","doi":"10.1016/j.jconhyd.2026.104844","DOIUrl":"10.1016/j.jconhyd.2026.104844","url":null,"abstract":"<div><div>Microplastics (MPs) originating from plastic waste in groundwater have attracted much attention worldwide due to their wide distribution, small particle size and high mobility, as well as their potential threat to organisms. In this study, a magnetically modified biochar adsorbent for the removal of microplastics was prepared using KOH-activated industrial hemp straw biochar as a precursor. For polystyrene (PS) microspheres (1 μm, 60 mg/L) in aqueous solution, magnetic biochar (MBC) removed 89.97 %, which was 9.30 times higher removal rate compared to pristine biochar (BC). It is hypothesized that the adsorption process was a result of electrostatic interactions and chemical bonding interactions between microplastics and biochar. The adsorption process was affected by solution pH and interfering ions, and the MBC had good stability, and its removal efficiency of MPs remained above 80 % after 5 cycles. Kinetic, isothermal and thermodynamic modeling analyses showed that the adsorption reaction was spontaneous, higher temperature contributed to the enhancement of adsorption, and the adsorption mechanism involved electrostatic interactions, surface complexation, metal-O-MPs complexation and π-π interactions. These results would provide an idea for obtaining MBC to remove the MPs from aqueous systems.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104844"},"PeriodicalIF":4.4,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145917635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Fate, chlorination kinetics, and comprehensive risk assessment of pharmaceuticals and personal care products in drinking water distribution systems","authors":"Zhenglin Li ,&nbsp;Nan Li ,&nbsp;Fei Wang ,&nbsp;Minru Xiao ,&nbsp;Anlei Wei","doi":"10.1016/j.jconhyd.2026.104842","DOIUrl":"10.1016/j.jconhyd.2026.104842","url":null,"abstract":"<div><div>The widespread occurrence of pharmaceuticals and personal care products (PPCPs) in aquatic environments has emerged as a global concern due to their potential threats to water security and ecological health. Despite increasing attention, their fate and associated risks in drinking water systems remain insufficiently understood. The occurrence, transformation behavior, and ecological and human health risks of 19 PPCPs were investigated across drinking water treatment and distribution systems in this study. Eighteen PPCPs were ubiquitously detected in raw water, with high detection frequencies (&gt;70 %), whereas both the number of detected compounds and their concentrations were markedly reduced in finished water (five compounds) and tap water (eleven compounds). These results demonstrate the substantial effectiveness of conventional treatment processes in reducing both the diversity and concentrations of PPCPs. To further elucidate their potential transformation during water treatment, chlorination kinetics of eight structurally diverse PPCPs were evaluated under controlled conditions. Four compounds (atenolol, sulpiride, paroxetine, and nadolol) exhibited pseudo-first-order kinetics with residual chlorine, while the others exhibited significant resistance to chlorination. Degradation efficiency was found to depend on both the water matrix conditions and their molecular properties, highlighting the combined roles of intrinsic chemical properties and environmental complexity. Ecological risk assessment revealed ibuprofen posed a moderate ecological risk, a risk quotient (RQ) of 0.335, while triclocarban presented a high ecological risk (RQ = 4.6031). Mixture toxicity assessment based on the cumulative toxic unit (ΣTU) further indicated a potential ecological risk (ΣTU &gt; 1) in raw water. Human health risk assessment showed minimal risks across all age groups (RQ 〈10⁻³). However, infants were identified as the most susceptible population, likely due to their higher exposure relative to body weight. Among the detected PPCPs, meclofenamic acid was identified as the compound of highest concern, with average relative risk indices exceeding &gt;10⁻⁴. These findings provide critical insights into the fate and transformation of PPCPs in drinking water systems and offer scientific guidance for optimizing treatment processes and risk management strategies.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104842"},"PeriodicalIF":4.4,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Distinguishing natural from mining-related metal sources by including streambank groundwater data in a stream mass loading study","authors":"Andrew H. Manning ,&nbsp;Robert L. Runkel ,&nbsp;Jean M. Morrison ,&nbsp;Sara Warix ,&nbsp;Richard B. Wanty ,&nbsp;Katherine Walton-Day ,&nbsp;Michael Snook","doi":"10.1016/j.jconhyd.2026.104841","DOIUrl":"10.1016/j.jconhyd.2026.104841","url":null,"abstract":"<div><div>Distinguishing stream metal loading caused by mine features from that caused by natural background sources remains challenging, yet this distinction is essential for making effective remedial decisions at many legacy mine sites. We combine a stream tracer injection and synoptic sampling study with data from shallow near-stream groundwater wells to estimate left-bank versus right-bank metal loading contributions at the 100-m spatial scale. The study was performed in the East Mancos River, a mountain headwater stream in Colorado, USA. The dominant source of elevated stream metal concentrations could be either groundwater infiltration through right-bank Doyle Mine waste piles or natural acid rock drainage from hydrothermally altered bedrock located mainly on the left bank. For the five metals of concern (Cu, Al, Zn, Cd, and Mn), we find that 15 % of the load contributed by diffuse groundwater inputs in the section potentially influenced by Doyle mine waste originates from the right bank. This right-bank potential mine contribution equates to only 3 % of the total watershed instream load for these metals. Furthermore, apparent ³H/³He groundwater ages in segments contributing most of the right-bank metal loading are sufficiently old (9–12 yr) to suggest that infiltration through the waste piles, located only 140–180 m from the stream, is unlikely. Estimated potential Doyle mine loading contributions can therefore be considered maximum values. Study results thus indicate that Doyle mine waste piles are a minor source of metal loading under low-flow conditions, and streambank groundwater data can provide valuable additional information in stream mass loading studies.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104841"},"PeriodicalIF":4.4,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Nitrate dynamics in the Dongjiang River watershed: Human impacts in the context of an Anthropocene River","authors":"Yaotong Gao ,&nbsp;Bingjun Liu ,&nbsp;Qian Tan ,&nbsp;Kai He ,&nbsp;Wei Ouyang ,&nbsp;Yaling Yu","doi":"10.1016/j.jconhyd.2026.104843","DOIUrl":"10.1016/j.jconhyd.2026.104843","url":null,"abstract":"<div><div>Rivers in the Anthropocene are increasingly impacted by human activities, with nitrate (NO₃⁻) pollution posing a significant threat to water quality and ecosystem health. This study investigates the Dongjiang River watershed as a representative example of such systems impacted by human activities. Using nitrate dual isotopes (δ¹⁵N-NO₃⁻ and δ¹⁸O-NO₃⁻) and a Bayesian mixing model (MixSIAR), we identified the sources and transformation processes of NO₃⁻ in the downstream Dongjiang River. Our results indicate that manure and sewage (MS) account for the majority of NO₃⁻ inputs (64.52 %), followed by soil nitrogen (SN) at 18.88 %. The influence of MS is amplified in catchments with higher urbanization, while forested areas show more significant contributions from SN. Seasonal variations in nitrate sources were also observed, with MS dominating during the dry season and SN contributions increasing during the wet season. Nitrification and denitrification were relatively weak during our sampling periods, as indicated by the absence of a characteristic δ¹⁵N-NO₃⁻ versus δ¹⁸O-NO₃⁻ slope (∼50 %) and by low extent of denitrification values at most sites; thus, external inputs were likely the primary drivers of NO₃⁻ dynamics. Furthermore, we link socio-economic factors and water consumption patterns to specific NO₃⁻ sources, highlighting the role of urbanization, economic development, and agricultural practices in shaping nitrate pollution. These findings provide critical insights for managing water quality and mitigating anthropogenic impacts on the Dongjiang River in the Anthropocene.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104843"},"PeriodicalIF":4.4,"publicationDate":"2026-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}