Pub Date : 2026-01-08DOI: 10.1016/j.jconhyd.2026.104840
D. Sanz , D. Salcedo , B. Toledo , I. Dountcheva , R. Margalef-Martí , N. Otero , A. Soler , J.J. Gómez-Alday
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.
{"title":"Anthropogenically-induced saline wetland recharge drives denitrification: Implications for nitrate attenuation in semi-arid aquifer–wetland systems","authors":"D. Sanz , D. Salcedo , B. Toledo , I. Dountcheva , R. Margalef-Martí , N. Otero , A. Soler , 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<sup>−</sup> 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 δ<sup>15</sup>N–NO₃<sup>−</sup> values ranging from +5.1 ‰ to +44 ‰ and δ<sup>18</sup>O–NO₃<sup>−</sup> from +3 ‰ to +23 ‰, along with δ<sup>34</sup>S–SO₄<sup>2−</sup> values between +16 ‰ and + 18 ‰ and δ<sup>13</sup>C–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}
Pub Date : 2026-01-07DOI: 10.1016/j.jconhyd.2026.104847
Yaning Xu , Wenxi Lu , Liuzhi Zhu , Qingchun Yang
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.
{"title":"Identification of time-varying contaminant discharge rates using a data-driven Transformer model","authors":"Yaning Xu , Wenxi Lu , Liuzhi Zhu , 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}
Pub Date : 2026-01-06DOI: 10.1016/j.jconhyd.2026.104845
Grigory Artemiev , Nadezhda Popova , Alexey Averin , Anatoly Boguslavsky , Ivan Morozov , Olga Zakusina , Victoria Krupskaya , Alexey Safonov
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.
{"title":"Laboratory modeling of microbial and chemical clay minerals transformations of upper aquifer soils under intensive technogenic impact","authors":"Grigory Artemiev , Nadezhda Popova , Alexey Averin , Anatoly Boguslavsky , Ivan Morozov , Olga Zakusina , Victoria Krupskaya , 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}
Pub Date : 2026-01-06DOI: 10.1016/j.jconhyd.2026.104846
Aipu Wu , Chunzi Ma , Shouliang Huo , Tianxiao Li , Qiang Fu
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.
{"title":"Vegetation type dominates slope-scale material loss under extreme rainfall: Nonlinear responses revealed by machine learning","authors":"Aipu Wu , Chunzi Ma , Shouliang Huo , Tianxiao Li , 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 (I<sub>30</sub>), 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 (I<sub>60</sub>) 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 I<sub>30</sub>, with sharp increases between 30 and 40 mm·h<sup>−1</sup>. 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}
Pub Date : 2026-01-05DOI: 10.1016/j.jconhyd.2026.104844
Xi Jiang , Youxi Cai , Hanwen Deng , Xiaolei Li
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.
来源于地下水中塑料垃圾的微塑料因其分布广泛、粒径小、流动性强以及对生物的潜在威胁而受到世界各国的广泛关注。本研究以koh活化的工业大麻秸秆生物炭为前驱体,制备了一种用于去除微塑料的磁性改性生物炭吸附剂。磁性生物炭(MBC)对聚苯乙烯(PS)微球(1 μm, 60 mg/L)的去除率为89.97%,是原始生物炭(BC)的9.30倍。假设吸附过程是微塑料与生物炭之间静电相互作用和化学键相互作用的结果。吸附过程受溶液pH和干扰离子的影响,MBC具有良好的稳定性,循环5次后对MPs的去除率保持在80%以上。动力学、等温和热力学模型分析表明,吸附反应是自发的,温度升高有助于吸附的增强,吸附机理涉及静电相互作用、表面络合作用、金属- o - mps络合作用和π-π相互作用。这些结果将为获得从水体系中去除MPs的MBC提供思路。
{"title":"Adsorption and mechanism of magnetically modified industrial hemp straw biochar on microplastics in aqueous solution","authors":"Xi Jiang , Youxi Cai , Hanwen Deng , 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}
Pub Date : 2026-01-05DOI: 10.1016/j.jconhyd.2026.104842
Zhenglin Li , Nan Li , Fei Wang , Minru Xiao , Anlei Wei
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 (>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 > 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 >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.
{"title":"Fate, chlorination kinetics, and comprehensive risk assessment of pharmaceuticals and personal care products in drinking water distribution systems","authors":"Zhenglin Li , Nan Li , Fei Wang , Minru Xiao , 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 (>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 > 1) in raw water. Human health risk assessment showed minimal risks across all age groups (RQ 〈10<sup>−3</sup>). 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 >10<sup>−4</sup>. 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}
Pub Date : 2026-01-05DOI: 10.1016/j.jconhyd.2026.104841
Andrew H. Manning , Robert L. Runkel , Jean M. Morrison , Sara Warix , Richard B. Wanty , Katherine Walton-Day , Michael Snook
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.
{"title":"Distinguishing natural from mining-related metal sources by including streambank groundwater data in a stream mass loading study","authors":"Andrew H. Manning , Robert L. Runkel , Jean M. Morrison , Sara Warix , Richard B. Wanty , Katherine Walton-Day , 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 <sup>3</sup>H/<sup>3</sup>He 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}
Pub Date : 2026-01-04DOI: 10.1016/j.jconhyd.2026.104843
Yaotong Gao , Bingjun Liu , Qian Tan , Kai He , Wei Ouyang , Yaling Yu
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.
{"title":"Nitrate dynamics in the Dongjiang River watershed: Human impacts in the context of an Anthropocene River","authors":"Yaotong Gao , Bingjun Liu , Qian Tan , Kai He , Wei Ouyang , 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 (NO<sub>3</sub><sup>−</sup>) 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 (δ<sup>15</sup>N-NO<sub>3</sub><sup>−</sup> and δ<sup>18</sup>O-NO<sub>3</sub><sup>−</sup>) and a Bayesian mixing model (MixSIAR), we identified the sources and transformation processes of NO<sub>3</sub><sup>−</sup> in the downstream Dongjiang River. Our results indicate that manure and sewage (MS) account for the majority of NO<sub>3</sub><sup>−</sup> 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 δ<sup>15</sup>N-NO<sub>3</sub><sup>−</sup> versus δ<sup>18</sup>O-NO<sub>3</sub><sup>−</sup> slope (∼50 %) and by low extent of denitrification values at most sites; thus, external inputs were likely the primary drivers of NO<sub>3</sub><sup>−</sup> dynamics. Furthermore, we link socio-economic factors and water consumption patterns to specific NO<sub>3</sub><sup>−</sup> 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}
Pub Date : 2026-01-01Epub Date: 2022-06-13DOI: 10.1080/13691058.2022.2083238
Amy Braksmajer, Rachel Kalish, Jennifer Katz
Young women must often contend with cultural scripts dictating neoliberal/postfeminist ideals of female sexual agency, including the ability to act in accord with one's personal sexual self-interest. The aim of this study was to explore how young women (n = 26) living with dyspareunia (pain experienced during penetrative sexual activity) negotiate these ideals. We found that in addition to discussing traditional discourses that assign value to women in accordance with their perceived sexual virtue, women judged themselves according to the degree to which their behaviour reflected sexual agency. Women perceived to be sexually agentic were, for the most part, lauded, while those perceived to lack sexual agency were either denigrated (in the case of high sexual activity) or seen as deficient (in the case of low sexual activity). The inability to be penetrated without pain significantly limited women's sexual repertoires. Contrasting their sexual agency with that of other women and of their past selves, women expressed feelings of disempowerment. Conceptualising agency as a spectrum rather than something that one has or lacks, as well as actively cultivating the potentialities of sexual 'transgression', may allow young women to resist heteronormative sexual hierarchies - including those rooted in a a postfeminist ethos.
{"title":"The scarlet V: how women with dyspareunia negotiate postfeminist discourses of sexual agency.","authors":"Amy Braksmajer, Rachel Kalish, Jennifer Katz","doi":"10.1080/13691058.2022.2083238","DOIUrl":"10.1080/13691058.2022.2083238","url":null,"abstract":"<p><p>Young women must often contend with cultural scripts dictating neoliberal/postfeminist ideals of female sexual agency, including the ability to act in accord with one's personal sexual self-interest. The aim of this study was to explore how young women (<i>n</i> = 26) living with dyspareunia (pain experienced during penetrative sexual activity) negotiate these ideals. We found that in addition to discussing traditional discourses that assign value to women in accordance with their perceived sexual virtue, women judged themselves according to the degree to which their behaviour reflected sexual agency. Women perceived to be sexually agentic were, for the most part, lauded, while those perceived to lack sexual agency were either denigrated (in the case of high sexual activity) or seen as deficient (in the case of low sexual activity). The inability to be penetrated without pain significantly limited women's sexual repertoires. Contrasting their sexual agency with that of other women and of their past selves, women expressed feelings of disempowerment. Conceptualising agency as a spectrum rather than something that one has or lacks, as well as actively cultivating the potentialities of sexual 'transgression', may allow young women to resist heteronormative sexual hierarchies - including those rooted in a a postfeminist ethos.</p>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"36 1","pages":"130-145"},"PeriodicalIF":4.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77912406","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}
Pub Date : 2025-12-31DOI: 10.1016/j.jconhyd.2025.104838
Bo Zhou , Xiangqin Xu , Xinyan Wang , Weijun Tian , Jiayu Peng , Kun Lei
Based on historical data (2020–2024) and intensified sampling in 2024 from the Qujiang River Basin, this study systematically analyzed the variations in water quality parameters across different hydrological periods. By integrating the Random Forest (RF) model, Positive Matrix Factorization (PMF), stable isotope techniques, and phosphorus speciation analysis, an optimized water quality assessment framework was constructed to accurately identify pollution sources. The results indicate that water temperature (T), pH, and permanganate index (CODMn) were significantly higher during the wet season, whereas dissolved oxygen (DO), ammonia nitrogen (NH4+-N), total nitrogen (TN), fluoride (F-), and organic carbon exhibited higher concentrations during the dry season. The RF model successfully reduced the number of key parameters required for Water Quality Index (WQI) evaluation from 10 to 5 (TP, TN, COD, DO, and BOD5), maintaining high predictive accuracy (R2 = 0.9245) while significantly lowering monitoring costs. Stable isotope tracing provided critical validation for the PMF model in identifying pollution sources and accurately constraining their contribution ratios. The results showed that TN primarily originated from sewage (70.7% in the wet season and 40.0% in the dry season) and soil/fertilizer sources. The PMF model identified four major pollution sources: industrial wastewater, agricultural fertilizers, domestic sewage, and seasonal climatic factors. Innovatively, the Random Forest algorithm was applied to weight and optimize the PMF outcomes. To bridge the gap between mathematical solutions and practical management, this study introduces a Random Forest-based weighting calibration for PMF-derived source apportionment, shifting the focus from numerical optimum to environmental accountability. After correction, industrial wastewater was identified as the dominant contributor (39.74% in the wet season and 36.68% in the dry season), a source that had been underestimated in conventional PMF results. Phosphorus speciation analysis further confirmed the influence of land use on pollutant composition. Dissolved organic phosphorus (DOP) dominated in urban areas, dissolved inorganic phosphorus (DIP) was prevalent in agricultural regions, and particulate organic phosphorus (POP) constituted the highest proportion in forested areas. This study reveals the dominant role of anthropogenic drivers in shaping water quality dynamics in rapidly urbanizing river basins and provides a scientific basis for targeted water pollution control strategies.
{"title":"Integrating random forest and isotopic tracers to optimize PMF-based source apportionment of watershed pollution","authors":"Bo Zhou , Xiangqin Xu , Xinyan Wang , Weijun Tian , Jiayu Peng , Kun Lei","doi":"10.1016/j.jconhyd.2025.104838","DOIUrl":"10.1016/j.jconhyd.2025.104838","url":null,"abstract":"<div><div>Based on historical data (2020–2024) and intensified sampling in 2024 from the Qujiang River Basin, this study systematically analyzed the variations in water quality parameters across different hydrological periods. By integrating the Random Forest (RF) model, Positive Matrix Factorization (PMF), stable isotope techniques, and phosphorus speciation analysis, an optimized water quality assessment framework was constructed to accurately identify pollution sources. The results indicate that water temperature (T), pH, and permanganate index (COD<sub>Mn</sub>) were significantly higher during the wet season, whereas dissolved oxygen (DO), ammonia nitrogen (NH<sub>4</sub><sup>+</sup>-N), total nitrogen (TN), fluoride (F<sup>-</sup>), and organic carbon exhibited higher concentrations during the dry season. The RF model successfully reduced the number of key parameters required for Water Quality Index (WQI) evaluation from 10 to 5 (TP, TN, COD, DO, and BOD<sub>5</sub>), maintaining high predictive accuracy (R<sup>2</sup> = 0.9245) while significantly lowering monitoring costs. Stable isotope tracing provided critical validation for the PMF model in identifying pollution sources and accurately constraining their contribution ratios. The results showed that TN primarily originated from sewage (70.7% in the wet season and 40.0% in the dry season) and soil/fertilizer sources. The PMF model identified four major pollution sources: industrial wastewater, agricultural fertilizers, domestic sewage, and seasonal climatic factors. Innovatively, the Random Forest algorithm was applied to weight and optimize the PMF outcomes. To bridge the gap between mathematical solutions and practical management, this study introduces a Random Forest-based weighting calibration for PMF-derived source apportionment, shifting the focus from numerical optimum to environmental accountability. After correction, industrial wastewater was identified as the dominant contributor (39.74% in the wet season and 36.68% in the dry season), a source that had been underestimated in conventional PMF results. Phosphorus speciation analysis further confirmed the influence of land use on pollutant composition. Dissolved organic phosphorus (DOP) dominated in urban areas, dissolved inorganic phosphorus (DIP) was prevalent in agricultural regions, and particulate organic phosphorus (POP) constituted the highest proportion in forested areas. This study reveals the dominant role of anthropogenic drivers in shaping water quality dynamics in rapidly urbanizing river basins and provides a scientific basis for targeted water pollution control strategies.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104838"},"PeriodicalIF":4.4,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880912","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}