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}
Pub Date : 2025-12-31DOI: 10.1016/j.jconhyd.2025.104839
Aifang Pan , Runyong Ma , Jianwu Zhang , Dahong Chen , Longyue Li , Yao Ke
Efficient removal of inorganic suspended matter is crucial for the recovery of soil leaching alkaline wastewater. This study aimed to develop a high-alumina inorganic polymer coagulant, polymerized aluminum ferric sulfate (PAFS), specifically targeting inorganic suspended matter in alkaline soil leaching wastewater. PAFS was prepared from aluminum ferric sulfate (Al0.862Fe0.138(SO4)3·nH2O) synthesized from Baihe pyrite slag, enabling resource utilization of this industrial waste. The physicochemical properties of the slag, intermediate sulfate, and final PAFS were characterized by XRD, SEM, and FT-IR. The optimal synthesis conditions were pH 3.0, aging temperature 80 °C, aging time 75 min, and combined AlFe content 11 %. The coagulation mechanism was systematically investigated, revealing a three-stage pH-dependent synergy of “charge neutralization - adsorption bridging - precipitation”: (1) At pH 1.0–2.0, low-polymerization PAFS destabilizes colloids via charge neutralization; (2) At the optimal pH 3.0, enhanced hydrolysis produces multi-nuclear hydroxo-complexes ([Fe2(OH)2]4+ and [Al13O4(OH)24]7+) that efficiently bridge particles into dense, settleable flocs through hydroxo bridging and sweep flocculation; (3) The sulfate-linked FeAl copolymer structure imparts superior alkali resistance, while over-hydrolysis at pH > 3.0 causes precipitation and efficiency loss. In simulated wastewater treatment, PAFS achieved a 99.9 % turbidity removal rate under alkaline conditions (pH 8.0–11.0). This work provides an efficient, low-cost solution for alkaline soil leaching wastewater by converting pyrite slag into a high-performance coagulant, offering notable economic and environmental benefits.
{"title":"High-performance polymeric aluminum ferric sulfate from Baihe pyrite slag: Enhanced coagulation in soil leaching alkaline wastewater and mechanistic insights","authors":"Aifang Pan , Runyong Ma , Jianwu Zhang , Dahong Chen , Longyue Li , Yao Ke","doi":"10.1016/j.jconhyd.2025.104839","DOIUrl":"10.1016/j.jconhyd.2025.104839","url":null,"abstract":"<div><div>Efficient removal of inorganic suspended matter is crucial for the recovery of soil leaching alkaline wastewater. This study aimed to develop a high-alumina inorganic polymer coagulant, polymerized aluminum ferric sulfate (PAFS), specifically targeting inorganic suspended matter in alkaline soil leaching wastewater. PAFS was prepared from aluminum ferric sulfate (Al<sub>0.862</sub>Fe<sub>0.138</sub>(SO<sub>4</sub>)<sub>3</sub>·nH<sub>2</sub>O) synthesized from Baihe pyrite slag, enabling resource utilization of this industrial waste. The physicochemical properties of the slag, intermediate sulfate, and final PAFS were characterized by XRD, SEM, and FT-IR. The optimal synthesis conditions were pH 3.0, aging temperature 80 °C, aging time 75 min, and combined Al<img>Fe content 11 %. The coagulation mechanism was systematically investigated, revealing a three-stage pH-dependent synergy of “charge neutralization - adsorption bridging - precipitation”: (1) At pH 1.0–2.0, low-polymerization PAFS destabilizes colloids via charge neutralization; (2) At the optimal pH 3.0, enhanced hydrolysis produces multi-nuclear hydroxo-complexes ([Fe<sub>2</sub>(OH)<sub>2</sub>]<sup>4+</sup> and [Al<sub>13</sub>O<sub>4</sub>(OH)<sub>24</sub>]<sup>7+</sup>) that efficiently bridge particles into dense, settleable flocs through hydroxo bridging and sweep flocculation; (3) The sulfate-linked Fe<img>Al copolymer structure imparts superior alkali resistance, while over-hydrolysis at pH > 3.0 causes precipitation and efficiency loss. In simulated wastewater treatment, PAFS achieved a 99.9 % turbidity removal rate under alkaline conditions (pH 8.0–11.0). This work provides an efficient, low-cost solution for alkaline soil leaching wastewater by converting pyrite slag into a high-performance coagulant, offering notable economic and environmental benefits.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104839"},"PeriodicalIF":4.4,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145917571","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 : 2025-12-29DOI: 10.1016/j.jconhyd.2025.104834
Mouigni Baraka Nafouanti , Junxia Li , Usman Sunusi Usman , Grant Charles Mwakipunda , Etsu Binta Fatima , Abdullah Sani Baba
Groundwater quality degradation is a significant challenge in the North China Plain (NCP), where groundwater is the primary source of water. Traditional methods for assessing groundwater quality, such as laboratory and hydraulic analyses, are costly and time-consuming. This study applies novel hybrid models for classification and regression analysis, including Stacking Classifiers (XGBoost, LightGBM), Hybrid LightGBM with Particle Swarm Optimization (LightGBM-PSO), Genetic Algorithm with Random Forest (GA-RF), and Genetic Algorithm with LightGBM (GA-LightGBM) to predict groundwater quality in Cangzhou. A total of 460 groundwater chemistry samples were collected to assess the quality of groundwater. The results of the hydrochemistry revealed that the dominant ions are HCO3−, Cl−, Ca2+, and SO42−. The primary water types identified were Na-HCO3, NaCl, Ca-HCO3, and Ca-Na-HCO3, indicating the significant impact of water-rock interactions, evaporation, and salinization. For the prediction of groundwater quality, the hybrid models LightGBM-PSO and GA-RF demonstrated the highest accuracy, achieving 93 %, 95 %, and 99 % accuracy for Classes 0, 1, and 2, respectively. The GA-RF model showed strong predictive performance with an R2 of 0.99, RMSE of 0.01, and MAE of 0.02. The SHAP analysis identified key features influencing groundwater quality, including Na+, HCO3−, F−, Cl−, Ca2+, SO42−, Mg2+, TDS, and EC. The Water Quality Index (WQI) classified 60.28 % of the samples as excellent or good, while 40 % were categorized as poor or very poor. These findings highlight the effectiveness of hybrid models in predicting groundwater quality and offer valuable insights for groundwater resource management, not only in Cangzhou but globally.
{"title":"Groundwater quality prediction using novel hybrid classification and regression models","authors":"Mouigni Baraka Nafouanti , Junxia Li , Usman Sunusi Usman , Grant Charles Mwakipunda , Etsu Binta Fatima , Abdullah Sani Baba","doi":"10.1016/j.jconhyd.2025.104834","DOIUrl":"10.1016/j.jconhyd.2025.104834","url":null,"abstract":"<div><div>Groundwater quality degradation is a significant challenge in the North China Plain (NCP), where groundwater is the primary source of water. Traditional methods for assessing groundwater quality, such as laboratory and hydraulic analyses, are costly and time-consuming. This study applies novel hybrid models for classification and regression analysis, including Stacking Classifiers (XGBoost, LightGBM), Hybrid LightGBM with Particle Swarm Optimization (LightGBM-PSO), Genetic Algorithm with Random Forest (GA-RF), and Genetic Algorithm with LightGBM (GA-LightGBM) to predict groundwater quality in Cangzhou. A total of 460 groundwater chemistry samples were collected to assess the quality of groundwater. The results of the hydrochemistry revealed that the dominant ions are HCO<sub>3</sub><sup>−</sup>, Cl<sup>−</sup>, Ca<sup>2+</sup>, and SO<sub>4</sub><sup>2−</sup>. The primary water types identified were Na-HCO<sub>3</sub>, Na<img>Cl, Ca-HCO<sub>3</sub>, and Ca-Na-HCO<sub>3</sub>, indicating the significant impact of water-rock interactions, evaporation, and salinization. For the prediction of groundwater quality, the hybrid models LightGBM-PSO and GA-RF demonstrated the highest accuracy, achieving 93 %, 95 %, and 99 % accuracy for Classes 0, 1, and 2, respectively. The GA-RF model showed strong predictive performance with an R<sup>2</sup> of 0.99, RMSE of 0.01, and MAE of 0.02. The SHAP analysis identified key features influencing groundwater quality, including Na<sup>+</sup>, HCO<sub>3</sub><sup>−</sup>, F<sup>−</sup>, Cl<sup>−</sup>, Ca<sup>2+</sup>, SO<sub>4</sub><sup>2−</sup>, Mg<sup>2+</sup>, TDS, and EC. The Water Quality Index (WQI) classified 60.28 % of the samples as excellent or good, while 40 % were categorized as poor or very poor. These findings highlight the effectiveness of hybrid models in predicting groundwater quality and offer valuable insights for groundwater resource management, not only in Cangzhou but globally.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104834"},"PeriodicalIF":4.4,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145878478","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 : 2025-12-29DOI: 10.1016/j.jconhyd.2025.104837
Lirong Zhong, Jonah A. Bartrand, Katherine A. Muller, Rob D. Mackley, Jonathan N. Thomle, Zoe G. Vincent
This laboratory-based study evaluated the performance and long-term (months) stability of colloidal silica (CS) gels in blocking vertical water flow and controlling chemical transport in subsurface applications, especially in the well annuli of long-screened wells. Laboratory-scale rheological tests demonstrated the injectivity of CS suspensions in expected field applications. Laboratory column, sandbox experiments and numerical modeling were used to assess the efficacy of CS gel in reducing hydraulic conductivities of the well annulus system. Further, a contaminant diffusion test was applied to evaluate the performance of CS gel-sand pack in mitigating transport of contamination. Rheological analyses highlighted the shear-thinning behavior of modified CS suspensions, facilitating more efficient injections in field applications. Hydraulic conductivity (K) tests revealed notable K reductions following CS gel injection, confirming its effectiveness in blocking vertical water flow. Diffusion tests demonstrated that no hexavalent chromium (Cr(VI)) migrated through CS gel-grouted sand barriers in 6 months, suggesting their strong potential as containment solutions for hazardous contaminants. Numerical simulations validated experimental data to reinforce the performance assessment of CS gels as barriers. The findings underscore CS gel's promising applications not only in long-screened well annular systems, but also in subsurface remediation, groundwater protection, and contaminant containment, providing critical insights for field-scale implementations.
{"title":"Performance and longevity of colloidal silica gel in blocking vertical water flow and contaminant transport in the annuli of long-screened wells: Laboratory and numerical evaluation","authors":"Lirong Zhong, Jonah A. Bartrand, Katherine A. Muller, Rob D. Mackley, Jonathan N. Thomle, Zoe G. Vincent","doi":"10.1016/j.jconhyd.2025.104837","DOIUrl":"10.1016/j.jconhyd.2025.104837","url":null,"abstract":"<div><div>This laboratory-based study evaluated the performance and long-term (months) stability of colloidal silica (CS) gels in blocking vertical water flow and controlling chemical transport in subsurface applications, especially in the well annuli of long-screened wells. Laboratory-scale rheological tests demonstrated the injectivity of CS suspensions in expected field applications. Laboratory column, sandbox experiments and numerical modeling were used to assess the efficacy of CS gel in reducing hydraulic conductivities of the well annulus system. Further, a contaminant diffusion test was applied to evaluate the performance of CS gel-sand pack in mitigating transport of contamination. Rheological analyses highlighted the shear-thinning behavior of modified CS suspensions, facilitating more efficient injections in field applications. Hydraulic conductivity (K) tests revealed notable K reductions following CS gel injection, confirming its effectiveness in blocking vertical water flow. Diffusion tests demonstrated that no hexavalent chromium (Cr(VI)) migrated through CS gel-grouted sand barriers in 6 months, suggesting their strong potential as containment solutions for hazardous contaminants. Numerical simulations validated experimental data to reinforce the performance assessment of CS gels as barriers. The findings underscore CS gel's promising applications not only in long-screened well annular systems, but also in subsurface remediation, groundwater protection, and contaminant containment, providing critical insights for field-scale implementations.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104837"},"PeriodicalIF":4.4,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880910","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 : 2025-12-29DOI: 10.1016/j.jconhyd.2025.104835
Tong Wang , Jiayi Kou , Fengjunxi Chen , Yalong Li , Yaojen Tu , Yanping Duan
Surface water quality dynamics is a pivotal factor in sustainable water management. As a strategic waterway in Taihu Lake Basin (China), Taipu River plays a key role in integrating water management through flood control, water supply, and ecological preservation across Jiangsu, Zhejiang, and Shanghai. However, under evolving anthropogenic pressures, systematic studies characterizing its nutrient spatiotemporal variations and pollution drivers remain limited. In this study, the spatiotemporal (October 2020–July 2021 from upstream to downstream) distributions and source characteristics of key nutrients from Taipu River were evaluated through various water quality index methods, coupled with multi-approach source apportionment (principal component analysis and positive matrix factorization). Results indicated that the concentrations of total nitrogen (TN) and chemical oxygen demand (COD) in Taipu River gradually increased from upstream (TN: 0.9–1.2 mg L−1, COD: 11.5–15.2 mg L−1) to downstream (TN: 1.1–1.9 mg L−1, COD:11.0–21.7 mg L−1), and exceeded regulatory Class III limits in summer/winter (>1.0 mg L−1) and spring/autumn (>20 mg L−1), respectively. The increased TN likely resulted from nitrogen fertilizer loss due to rainfall, whereas the increase in COD is probably linked to the release of metabolic products from algae. Water contamination analyses identified a slightly-contaminated T7 site (i.e., TN = 1.51 ± 0.71 mg L−1, COD = 34 ± 9.0 mg L−1, exceeding Class IV), with primary contamination sources attributed to industrial activity (e.g., textile industry). For this T7 site with slight water contamination, the in-situ remediation strategies such as adding synthetic microbiomes, incorporating aquatic plants, and engineering intervention for nitrogen and COD pollution are recommended. These findings highlight the urgent requirement for targeted measures to mitigate nitrogen/COD loads, which is crucial to improve water quality and ecosystem health of the Taihu Lake Basin.
{"title":"Deciphering the spatiotemporal dynamics and source characteristics of nutrients under anthropogenic pressure in Taipu River, China","authors":"Tong Wang , Jiayi Kou , Fengjunxi Chen , Yalong Li , Yaojen Tu , Yanping Duan","doi":"10.1016/j.jconhyd.2025.104835","DOIUrl":"10.1016/j.jconhyd.2025.104835","url":null,"abstract":"<div><div>Surface water quality dynamics is a pivotal factor in sustainable water management. As a strategic waterway in Taihu Lake Basin (China), Taipu River plays a key role in integrating water management through flood control, water supply, and ecological preservation across Jiangsu, Zhejiang, and Shanghai. However, under evolving anthropogenic pressures, systematic studies characterizing its nutrient spatiotemporal variations and pollution drivers remain limited. In this study, the spatiotemporal (October 2020–July 2021 from upstream to downstream) distributions and source characteristics of key nutrients from Taipu River were evaluated through various water quality index methods, coupled with multi-approach source apportionment (principal component analysis and positive matrix factorization). Results indicated that the concentrations of total nitrogen (TN) and chemical oxygen demand (COD) in Taipu River gradually increased from upstream (TN: 0.9–1.2 mg L<sup>−1</sup>, COD: 11.5–15.2 mg L<sup>−1</sup>) to downstream (TN: 1.1–1.9 mg L<sup>−1</sup>, COD:11.0–21.7 mg L<sup>−1</sup>), and exceeded regulatory Class III limits in summer/winter (>1.0 mg L<sup>−1</sup>) and spring/autumn (>20 mg L<sup>−1</sup>), respectively. The increased TN likely resulted from nitrogen fertilizer loss due to rainfall, whereas the increase in COD is probably linked to the release of metabolic products from algae. Water contamination analyses identified a slightly-contaminated T7 site (i.e., TN = 1.51 ± 0.71 mg L<sup>−1</sup>, COD = 34 ± 9.0 mg L<sup>−1</sup>, exceeding Class IV), with primary contamination sources attributed to industrial activity (e.g., textile industry). For this T7 site with slight water contamination, the in-situ remediation strategies such as adding synthetic microbiomes, incorporating aquatic plants, and engineering intervention for nitrogen and COD pollution are recommended. These findings highlight the urgent requirement for targeted measures to mitigate nitrogen/COD loads, which is crucial to improve water quality and ecosystem health of the Taihu Lake Basin.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104835"},"PeriodicalIF":4.4,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880911","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}
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