Otin River is one of the longest strategic rivers in Osun State (Nigeria) with diverse economic values: commercial fishing, community water supply, farming and domestic activities. Nineteen toxic polychlorinated biphenyls (PCBs) were studied in the river water to understand their contamination levels, sources and potential health threats to humans. The river water samples were collected from six locations. The PCBs were extracted by liquid-liquid extraction and quantified using a gas chromatograph-mass spectrometer (GC–MS). All the PCBs were detected in the river water, ranging from 0.002 μg/L (PCB206) to 0.96 μg/L (PCB180). Using the average concentration of the individual PCB measured, their total concentration was 2.96 μg/L, which exceeded the standard permissible limit of 0.5 μg/L for drinking water. This indicated a high level of contamination. The six dominant congeners in the river water were in the following order: PCB180 > PCB170 > PCB44 > PCB5 > PCB187 > PCB18 (0.12 μg/L). The total PCB concentration at the river midstream housing the Eko-Ende Dam was significantly higher (P < 0.05) than that measured at the upstream and downstream. Using principal component analysis, the PCB sources were profiled as the dam's hydraulic system, plastics, paints and farm's agrochemical runoffs. Of the 19 PCBs, PCB5, PCB44, PCB170 and PCB180 posed both non-carcinogenic and carcinogenic risks to human health. PCB170 and PCB180 posed the highest risks via ingestion. Some residents/farmers usually consume the water. Thus, the PCB concentrations could cause unimaginable health risks to the people and aquatic life, necessitating effective management strategies.
{"title":"Quantitative profile, sources and health implications of polychlorinated biphenyls (PCBs) in the strategic Otin River water, Nigeria","authors":"Adebanjo Jacob Anifowose, Mariam Abolore Muritala, Aaliyah Omotayo Bello, Abosede Susannah Oguntolu, Kazeem Abiodun Ibrahim, Shola Hezekiah Awojide","doi":"10.1016/j.jconhyd.2025.104826","DOIUrl":"10.1016/j.jconhyd.2025.104826","url":null,"abstract":"<div><div>Otin River is one of the longest strategic rivers in Osun State (Nigeria) with diverse economic values: commercial fishing, community water supply, farming and domestic activities. Nineteen toxic polychlorinated biphenyls (PCBs) were studied in the river water to understand their contamination levels, sources and potential health threats to humans. The river water samples were collected from six locations. The PCBs were extracted by liquid-liquid extraction and quantified using a gas chromatograph-mass spectrometer (GC–MS). All the PCBs were detected in the river water, ranging from 0.002 μg/L (PCB206) to 0.96 μg/L (PCB180). Using the average concentration of the individual PCB measured, their total concentration was 2.96 μg/L, which exceeded the standard permissible limit of 0.5 μg/L for drinking water. This indicated a high level of contamination. The six dominant congeners in the river water were in the following order: PCB180 > PCB170 > PCB44 > PCB5 > PCB187 > PCB18 (0.12 μg/L). The total PCB concentration at the river midstream housing the Eko-Ende Dam was significantly higher (<em>P</em> < 0.05) than that measured at the upstream and downstream. Using principal component analysis, the PCB sources were profiled as the dam's hydraulic system, plastics, paints and farm's agrochemical runoffs. Of the 19 PCBs, PCB5, PCB44, PCB170 and PCB180 posed both non-carcinogenic and carcinogenic risks to human health. PCB170 and PCB180 posed the highest risks via ingestion. Some residents/farmers usually consume the water. Thus, the PCB concentrations could cause unimaginable health risks to the people and aquatic life, necessitating effective management strategies.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104826"},"PeriodicalIF":4.4,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145863093","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}
The groundwater resource in the coastal aquifers is highly vulnerable to seawater intrusion and salinization, triggered by multiple physical and anthropogenic factors. Therefore, the present study aims to address this pressing issue in the eastern coastal region of India based on 10 hydrochemical parameters of 1228 groundwater samples coupled with 15 lithologs, and annual groundwater draft for irrigation, industry, and domestic data for 37 coastal districts of the study area. The results reveal that 39.09 % of the samples are recorded as saline by the hydrochemical facies evolution diagram, while 55.09 % of the samples exhibit SMI >1, indicating the widespread presence of seawater intrusion into coastal aquifers. The region-specific study of SMI reveals that 91 out of 134 samples (67.91 %) are identified as SMI > 1 in West Bengal while the corresponding proportions are 63.61 % for Tamil Nadu, 56.10 % for Andhra Pradesh, and 32.49 % for Odisha. The study has also revealed hotspots for SMI, and the coastal regions of Odisha, Andhra Pradesh, and Tamil Nadu are found with significant hotspots for groundwater salinization. The fine sand and silt layers of the aquifers play a conducive role for the presence of saline water through direct seepage from the sea. Moreover, the excessive groundwater draft (0–7.94 × 108 m3) for irrigation, (0–1.878 × 107 m3) for industrial, and (0–2.029 × 108 m3) for domestic uses shifts the hydraulic gradient landward, leading to the movement of saline water to the coastal aquifers.
{"title":"Characterizing seawater intrusion and groundwater vulnerability to salinization along the east coast of India","authors":"Biplab Sarkar , Aznarul Islam , Amit Kumar , Swapan Talukdar , Md Nawaj Sarif , Akanksha Pandey , Kaustubh Lahiri , Sutapa Mukherjee , Abdur Rahman , SK. Mafizul Haque , Abujar Rahaman","doi":"10.1016/j.jconhyd.2025.104829","DOIUrl":"10.1016/j.jconhyd.2025.104829","url":null,"abstract":"<div><div>The groundwater resource in the coastal aquifers is highly vulnerable to seawater intrusion and salinization, triggered by multiple physical and anthropogenic factors. Therefore, the present study aims to address this pressing issue in the eastern coastal region of India based on 10 hydrochemical parameters of 1228 groundwater samples coupled with 15 lithologs, and annual groundwater draft for irrigation, industry, and domestic data for 37 coastal districts of the study area. The results reveal that 39.09 % of the samples are recorded as saline by the hydrochemical facies evolution diagram, while 55.09 % of the samples exhibit SMI >1, indicating the widespread presence of seawater intrusion into coastal aquifers. The region-specific study of SMI reveals that 91 out of 134 samples (67.91 %) are identified as SMI > 1 in West Bengal while the corresponding proportions are 63.61 % for Tamil Nadu, 56.10 % for Andhra Pradesh, and 32.49 % for Odisha. The study has also revealed hotspots for SMI, and the coastal regions of Odisha, Andhra Pradesh, and Tamil Nadu are found with significant hotspots for groundwater salinization. The fine sand and silt layers of the aquifers play a conducive role for the presence of saline water through direct seepage from the sea. Moreover, the excessive groundwater draft (0–7.94 × 10<sup>8</sup> m<sup>3</sup>) for irrigation, (0–1.878 × 10<sup>7</sup> m<sup>3</sup>) for industrial, and (0–2.029 × 10<sup>8</sup> m<sup>3</sup>) for domestic uses shifts the hydraulic gradient landward, leading to the movement of saline water to the coastal aquifers.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104829"},"PeriodicalIF":4.4,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145911792","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 : 2025-12-26DOI: 10.1016/j.jconhyd.2025.104832
Yeonji Jeong , Jeongho Han , Seoro Lee , Sangjoon Bak , Gwanjae Lee , Jonggun Kim , Kyoung Jae Lim
This study introduces the WAPLE4 system, developed to accurately separate direct runoff and baseflow and calculate pollution loads while considering the recession characteristics of hydrographs under varying flow condition-specific. The system was applied to four major watersheds in South Korea, demonstrating improved accuracy in baseflow separation, with an average baseflow reduction of 7 % when the β parameter by flow condition-specific was applied. Furthermore, pollution load analysis revealed reductions in TP and TN loads by 10.92 % and 10.56 %, underscoring the effectiveness of this parameter in refining pollution load estimates. These findings highlight the system's ability to improve flow condition-specific baseflow and pollutant load calculations while reflecting the distinct characteristics of individual watersheds. By enabling precise quantification of pollutant loads from both direct runoff and baseflow, this system can be effectively utilized to provide foundational data for the development of more comprehensive watershed management strategies and aid decision-makers in addressing water quality challenges more effectively.
{"title":"Development and application evaluation of baseflow separation/pollution load estimation tool considering the characteristics of the recession by flow condition-specific","authors":"Yeonji Jeong , Jeongho Han , Seoro Lee , Sangjoon Bak , Gwanjae Lee , Jonggun Kim , Kyoung Jae Lim","doi":"10.1016/j.jconhyd.2025.104832","DOIUrl":"10.1016/j.jconhyd.2025.104832","url":null,"abstract":"<div><div>This study introduces the WAPLE4 system, developed to accurately separate direct runoff and baseflow and calculate pollution loads while considering the recession characteristics of hydrographs under varying flow condition-specific. The system was applied to four major watersheds in South Korea, demonstrating improved accuracy in baseflow separation, with an average baseflow reduction of 7 % when the <em>β</em> parameter by flow condition-specific was applied. Furthermore, pollution load analysis revealed reductions in TP and TN loads by 10.92 % and 10.56 %, underscoring the effectiveness of this parameter in refining pollution load estimates. These findings highlight the system's ability to improve flow condition-specific baseflow and pollutant load calculations while reflecting the distinct characteristics of individual watersheds. By enabling precise quantification of pollutant loads from both direct runoff and baseflow, this system can be effectively utilized to provide foundational data for the development of more comprehensive watershed management strategies and aid decision-makers in addressing water quality challenges more effectively.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104832"},"PeriodicalIF":4.4,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145952082","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 : 2025-12-24DOI: 10.1016/j.jconhyd.2025.104828
TeRi GeLe , Kaijun Lu , Zucheng Wang , Shasha Liu , Ziping Liu
The polycyclic aromatic hydrocarbons (PAH) concentrations along an urban river from Northeast China were investigated during snowmelt and non-snowmelt periods. The results showed that the concentration of dissolved PAHs in the samples collected during the snowmelt period ranged from 61 to 271 ng L−1, significantly lower than those in the non-snowmelt period, which ranged from 141 to 833 ng L−1 (p < 0.05). The highest PAH concentrations in river were generally observed at municipal sewage treatment outlet. PAH concentrations were positively correlated with SUVA254 value (p < 0.01) and negatively correlated with dissolved organic carbon (DOC), total nitrogen (TN), and total phosphorus (TP) (p < 0.01). PAH concentration increased from the upstream suburbs to urban areas, and downstream suburbs in snowmelt period, whereas an opposite trend was observed during non-snowmelt periods. These findings indicate that different factors control PAH concentration distribution along the urban river during two periods. However, despite the spatial distribution pattern of PAHs along the upstream-downstream gradient changing due to snowmelt, the overall PAH levels during snowmelt were not higher than those observed in the non-snowmelt period. This study implies that snowmelt may not always rapidly increase PAH concentrations in aquatic environment, especially in urban rivers.
对东北某城市河流在融雪期和非融雪期的多环芳烃(PAH)浓度进行了研究。结果表明:融雪期样品中溶解多环芳烃的浓度为61 ~ 271 ng L-1,显著低于非融雪期样品的141 ~ 833 ng L-1 (p 254值)
{"title":"Characteristics of polycyclic aromatic hydrocarbons along an urban river in snowmelt and non-snowmelt periods from Northeast China","authors":"TeRi GeLe , Kaijun Lu , Zucheng Wang , Shasha Liu , Ziping Liu","doi":"10.1016/j.jconhyd.2025.104828","DOIUrl":"10.1016/j.jconhyd.2025.104828","url":null,"abstract":"<div><div>The polycyclic aromatic hydrocarbons (PAH) concentrations along an urban river from Northeast China were investigated during snowmelt and non-snowmelt periods. The results showed that the concentration of dissolved PAHs in the samples collected during the snowmelt period ranged from 61 to 271 ng L<sup>−1</sup>, significantly lower than those in the non-snowmelt period, which ranged from 141 to 833 ng L<sup>−1</sup> (<em>p</em> < 0.05). The highest PAH concentrations in river were generally observed at municipal sewage treatment outlet. PAH concentrations were positively correlated with SUVA<sub>254</sub> value (<em>p</em> < 0.01) and negatively correlated with dissolved organic carbon (DOC), total nitrogen (TN), and total phosphorus (TP) (<em>p</em> < 0.01). PAH concentration increased from the upstream suburbs to urban areas, and downstream suburbs in snowmelt period, whereas an opposite trend was observed during non-snowmelt periods. These findings indicate that different factors control PAH concentration distribution along the urban river during two periods. However, despite the spatial distribution pattern of PAHs along the upstream-downstream gradient changing due to snowmelt, the overall PAH levels during snowmelt were not higher than those observed in the non-snowmelt period. This study implies that snowmelt may not always rapidly increase PAH concentrations in aquatic environment, especially in urban rivers.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104828"},"PeriodicalIF":4.4,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145850447","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}
Hydrogen is increasingly recognized as a pillar of future low-carbon energy systems, offering flexibility across multiple sectors and contributing to deep decarbonization goals. To enable large-scale deployment, Underground Hydrogen Storage (UHS) in geological formations such as saline aquifers is gaining considerable attention as a strategic option for ensuring secure and scalable energy reserves. The safety, efficiency, and operational success of UHS heavily depend on accurately determining interfacial tension (IFT) between hydrogen/cushion gas and the in-situ brine, as this parameter governs several critical phenomena related to storage performance. This study aims to develop a reliable and explainable machine learning framework to predict IFT in H2/cushion gas–brine systems across diverse thermodynamic and compositional conditions. Two input schemes were explored: the first included nine variables covering detailed salt composition, pressure, temperature, and the presence of cushion gas (represented by average critical temperature, Tcm); the second used a simplified set of four inputs, namely equivalent salinity, pressure, temperature, and Tcm. A curated database of approximately 500 experimentally measured IFT data points was employed to train and validate three models: radial basis function neural network (RBFNN), generalized regression neural network (GRNN), and categorical boosting (CatBoost). Among these, the CatBoost-based model under the simplified scheme achieved the highest predictive accuracy (R2 = 0.9979, RMSE = 0.5136 mN/m), with excellent physical consistency and generalization. Trend analysis confirmed the model's ability to replicate expected IFT behavior under varying conditions. Comparative benchmarking showed that the CatBoost model outperformed several state-of-the-art models from the literature. A leverage-based applicability domain analysis revealed that 97 % of the data points fall within acceptable influence and residual bounds, confirming robustness. Beyond accuracy, the model is highly interpretable globally and locally using SHAP and LIME techniques, making it suitable for real-time deployment in UHS operations to support safe injection design and long-term storage reliability.
{"title":"Explainable advanced modelling of interfacial tension in H2 – CO2 – CH4 – brine systems for sustainable subsurface storage in saline aquifer","authors":"Saad Alatefi , Okorie Ekwe Agwu , Menad Nait Amar , Ahmad Alkouh","doi":"10.1016/j.jconhyd.2025.104827","DOIUrl":"10.1016/j.jconhyd.2025.104827","url":null,"abstract":"<div><div>Hydrogen is increasingly recognized as a pillar of future low-carbon energy systems, offering flexibility across multiple sectors and contributing to deep decarbonization goals. To enable large-scale deployment, Underground Hydrogen Storage (UHS) in geological formations such as saline aquifers is gaining considerable attention as a strategic option for ensuring secure and scalable energy reserves. The safety, efficiency, and operational success of UHS heavily depend on accurately determining interfacial tension (IFT) between hydrogen/cushion gas and the in-situ brine, as this parameter governs several critical phenomena related to storage performance. This study aims to develop a reliable and explainable machine learning framework to predict IFT in H<sub>2</sub>/cushion gas–brine systems across diverse thermodynamic and compositional conditions. Two input schemes were explored: the first included nine variables covering detailed salt composition, pressure, temperature, and the presence of cushion gas (represented by average critical temperature, T<sub>cm</sub>); the second used a simplified set of four inputs, namely equivalent salinity, pressure, temperature, and T<sub>cm</sub>. A curated database of approximately 500 experimentally measured IFT data points was employed to train and validate three models: radial basis function neural network (RBFNN), generalized regression neural network (GRNN), and categorical boosting (CatBoost). Among these, the CatBoost-based model under the simplified scheme achieved the highest predictive accuracy (R<sup>2</sup> = 0.9979, RMSE = 0.5136 mN/m), with excellent physical consistency and generalization. Trend analysis confirmed the model's ability to replicate expected IFT behavior under varying conditions. Comparative benchmarking showed that the CatBoost model outperformed several state-of-the-art models from the literature. A leverage-based applicability domain analysis revealed that 97 % of the data points fall within acceptable influence and residual bounds, confirming robustness. Beyond accuracy, the model is highly interpretable globally and locally using SHAP and LIME techniques, making it suitable for real-time deployment in UHS operations to support safe injection design and long-term storage reliability.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104827"},"PeriodicalIF":4.4,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145863168","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 : 2025-12-24DOI: 10.1016/j.jconhyd.2025.104830
Md. Jaker Hossain , Sheikh Aftab Uddin , Lijun He , Huahong Shi , Jing Zhang
Rivers are major pathways of land-based plastic debris to the oceans, but limited data exist for microplastic (MP) flux from large river systems. This study examines the spatial and seasonal dynamics of MPs in the Ganges-Brahmaputra-Meghna (GBM) River system and estuary, a key contributor to global marine plastic pollution. MP abundances ranged from 1.53 to 8.13 items/L in the dry season and 2.67 to 7.67 items/L in the wet season, with no significant overall seasonal difference (p > 0.05). The dominated shape and color were fiber and blue, respectively, with the size class of 0.02–0.5 mm being predominant. The prevalent polymers during both seasons were rayon and polyethylene. MP transported into the Bay of Bengal (BoB) were calculated as 9.42 × 1012 items/day (1.17 tons/day) during dry season and 33.95 × 1012 items/day (10.78 tons/day) in wet season indicating that a substantial amount of MPs are being input to marine environment from GBM River system compared with other rivers globally. Risk assessments indicated high contamination levels (CF, PLI, and HI) and substantial ecological risks (RI) values in the entire study area with maximum pollution level gradient at the Ganges, Meghna and GBM confluence. These findings contribute important quantitative information on spatio-temporal patterns and load of MP, necessary for validation of global-level MP flux models and the development of focused mitigation strategies within the GBM basin.
{"title":"Spatio-temporal dynamics and flux of microplastics in the lower Ganges-Brahmaputra-Meghna River system and estuary","authors":"Md. Jaker Hossain , Sheikh Aftab Uddin , Lijun He , Huahong Shi , Jing Zhang","doi":"10.1016/j.jconhyd.2025.104830","DOIUrl":"10.1016/j.jconhyd.2025.104830","url":null,"abstract":"<div><div>Rivers are major pathways of land-based plastic debris to the oceans, but limited data exist for microplastic (MP) flux from large river systems. This study examines the spatial and seasonal dynamics of MPs in the Ganges-Brahmaputra-Meghna (GBM) River system and estuary, a key contributor to global marine plastic pollution. MP abundances ranged from 1.53 to 8.13 items/L in the dry season and 2.67 to 7.67 items/L in the wet season, with no significant overall seasonal difference (<em>p</em> > 0.05). The dominated shape and color were<!--> <!-->fiber and blue, respectively, with the size class of 0.02–0.5 mm being predominant. The prevalent polymers during both seasons<!--> <!-->were rayon and polyethylene. MP transported into the Bay of Bengal (BoB) were calculated as 9.42 × 10<sup>12</sup> items/day (1.17 tons/day) during dry season and 33.95 × 10<sup>12</sup> items/day (10.78 tons/day) in wet season indicating that a substantial amount of MPs are being input to<!--> <!-->marine environment from GBM River system compared with other rivers globally. Risk assessments indicated high contamination levels (CF<em>, PLI, and HI</em>) and substantial ecological risks (<em>RI</em>) values<!--> <!-->in the entire study area with maximum pollution level gradient at the Ganges, Meghna and GBM confluence. These findings contribute important quantitative<!--> <!-->information on spatio-temporal patterns and load of MP, necessary for validation of global-level MP flux models and the development of focused mitigation strategies within the GBM basin.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104830"},"PeriodicalIF":4.4,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145850430","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 : 2025-12-24DOI: 10.1016/j.jconhyd.2025.104821
Yupei Hao , Xueqin Wei , Tianyao Yang , Xiongyi Miao , Gaohai Xu , Sheping Yang , Xiaohua Zhou
The bioconversion of heavy metals (HMs) in sediments has received limited research attention, despite its critical importance for ecological risk assessment. The Liujiang River Basin, a typical karst catchment in Southwest China, provides an ideal context for investigating HM bioconversion due to the generally high bioavailability of HMs in its sediments. This study employed the Biotic Sediment Accumulation Factor (BSAF) to analyze spatio-temporal variations in the bioconversion of seven priority metals between sediments and wild fish. Results demonstrated that BSAF values for most HMs were significantly higher in the wet season than in the dry season. Zinc demonstrated the highest bioaccumulation potential, with its BSAF frequently exceeding 1 and reaching up to 1.99, unlike the other studied HMs. A clear correspondence was observed between BSAF values and oxidizable fractions, suggesting the crucial role of oxidizable forms in driving HM bioconversion. Multivariate correlation analysis further revealed that combined proportions of oxidizable and carbonate-bound fractions shaped three distinct bioconversion patterns: inhibited bioconversion under dual low fractions (resulting in low BSAFs), promoted bioconversion with a single high fraction, and significantly promoted bioconversion under dual high fractions (producing high BSAFs). Notably, seasonal variations in BSAF values between Pseudohemiculter dispar and Cyprinus carpio indicated that pelagic feeding amplifies the impact of exogenous HMs, while benthic feeding intensifies the influence of sediment-destabilized HMs. Given the dominant roles of carbonate-bound and oxidizable fractions, we recommend implementing strict wastewater emission controls coupled with enhanced dissolved oxygen levels in water bodies to effectively mitigate HM bioconversion in sediments.
{"title":"Bioconversion of heavy metals in river sediments: Seasonal dynamics, driving mechanisms, and BSAF-based assessment in the Liujiang River basin","authors":"Yupei Hao , Xueqin Wei , Tianyao Yang , Xiongyi Miao , Gaohai Xu , Sheping Yang , Xiaohua Zhou","doi":"10.1016/j.jconhyd.2025.104821","DOIUrl":"10.1016/j.jconhyd.2025.104821","url":null,"abstract":"<div><div>The bioconversion of heavy metals (HMs) in sediments has received limited research attention, despite its critical importance for ecological risk assessment. The Liujiang River Basin, a typical karst catchment in Southwest China, provides an ideal context for investigating HM bioconversion due to the generally high bioavailability of HMs in its sediments. This study employed the Biotic Sediment Accumulation Factor (BSAF) to analyze spatio-temporal variations in the bioconversion of seven priority metals between sediments and wild fish. Results demonstrated that BSAF values for most HMs were significantly higher in the wet season than in the dry season. Zinc demonstrated the highest bioaccumulation potential, with its BSAF frequently exceeding 1 and reaching up to 1.99, unlike the other studied HMs. A clear correspondence was observed between BSAF values and oxidizable fractions, suggesting the crucial role of oxidizable forms in driving HM bioconversion. Multivariate correlation analysis further revealed that combined proportions of oxidizable and carbonate-bound fractions shaped three distinct bioconversion patterns: inhibited bioconversion under dual low fractions (resulting in low BSAFs), promoted bioconversion with a single high fraction, and significantly promoted bioconversion under dual high fractions (producing high BSAFs). Notably, seasonal variations in BSAF values between <em>Pseudohemiculter dispar</em> and <em>Cyprinus carpio</em> indicated that pelagic feeding amplifies the impact of exogenous HMs, while benthic feeding intensifies the influence of sediment-destabilized HMs. Given the dominant roles of carbonate-bound and oxidizable fractions, we recommend implementing strict wastewater emission controls coupled with enhanced dissolved oxygen levels in water bodies to effectively mitigate HM bioconversion in sediments.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104821"},"PeriodicalIF":4.4,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837531","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}
Understanding virus transport in porous media is crucial for assessing the risks associated with viral contamination in subsurface environments. Plant and human viruses may enter water systems through agricultural runoff, wastewater discharge, or other pathways, necessitating a detailed investigation of their mobility and persistence. This study investigates the transport behavior of Tomato Brown Rugose Fruit Virus (ToBRFV), Pepper Mild Mottle Virus (PMMoV), and human adenovirus (HAdV) in porous media using controlled laboratory column experiments packed with uniform size glass beads. Breakthrough curves generated were analyzed using an advection-dispersion-reaction equation to model each virus's transport dynamics. The two plant-based viruses, ToBRFV and PMMoV, exhibited similar transport profiles with sharp breakthrough onsets and pronounced tailing, whereas HAdV showed a more gradual breakthrough, indicating distinct transport dynamics. The differences in transport were largely attributed to the morphological differences between plant viruses and human adenovirus. Additionally, variations in influent water chemistry, particularly pH, appear to significantly influence virus transport by modifying the DLVO interaction energy between viral particles and glass bead surfaces. While no direct one-to-one correlation was observed between the transport of HAdV and the plant viruses, statistical analysis revealed ToBRFV as a more reliable surrogate compared to PMMoV. By elucidating key factors influencing viral transport, this study provides insights that could inform risk assessments and mitigation strategies for waterborne viral contamination. These findings highlight the potential role of viral morphology and water chemistry in identifying reliable viral surrogates for subsurface transport assessments.
{"title":"Comparative analysis of column experiments highlights the suitability and challenges of using common plant-based viruses as surrogates for human adenovirus in saturated porous media","authors":"Emmanuel Cobbinah , Subhash C. Verma , Krishna Pagilla , Rishi Parashar","doi":"10.1016/j.jconhyd.2025.104831","DOIUrl":"10.1016/j.jconhyd.2025.104831","url":null,"abstract":"<div><div>Understanding virus transport in porous media is crucial for assessing the risks associated with viral contamination in subsurface environments. Plant and human viruses may enter water systems through agricultural runoff, wastewater discharge, or other pathways, necessitating a detailed investigation of their mobility and persistence. This study investigates the transport behavior of Tomato Brown Rugose Fruit Virus (ToBRFV), Pepper Mild Mottle Virus (PMMoV), and human adenovirus (HAdV) in porous media using controlled laboratory column experiments packed with uniform size glass beads. Breakthrough curves generated were analyzed using an advection-dispersion-reaction equation to model each virus's transport dynamics. The two plant-based viruses, ToBRFV and PMMoV, exhibited similar transport profiles with sharp breakthrough onsets and pronounced tailing, whereas HAdV showed a more gradual breakthrough, indicating distinct transport dynamics. The differences in transport were largely attributed to the morphological differences between plant viruses and human adenovirus. Additionally, variations in influent water chemistry, particularly pH, appear to significantly influence virus transport by modifying the DLVO interaction energy between viral particles and glass bead surfaces. While no direct one-to-one correlation was observed between the transport of HAdV and the plant viruses, statistical analysis revealed ToBRFV as a more reliable surrogate compared to PMMoV. By elucidating key factors influencing viral transport, this study provides insights that could inform risk assessments and mitigation strategies for waterborne viral contamination. These findings highlight the potential role of viral morphology and water chemistry in identifying reliable viral surrogates for subsurface transport assessments.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104831"},"PeriodicalIF":4.4,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837533","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 : 2025-12-23DOI: 10.1016/j.jconhyd.2025.104825
S.N. Corimayo , M.N. Maidana Kulesza , D. Gutiérrez-Cacciabue , V.B. Rajal , H.R. Poma
The persistence of waterborne virus persistence in surface waters may pose a risk to human health. To assess their persistence and mitigate exposure risks in aquatic environments is essential to understand how they (or their surrogates) interact with suspended sediments under different environmental conditions. These sediment particles can adsorb viral particles, influencing their transport, sedimentation, and persistence in aquatic environments. This study evaluated the decay of two virus surrogates, P22 (DNA phage) and PP7 (RNA phage), for enteric DNA and RNA viruses, respectively, in water environments. The phages decay was analyzed using synthetic water matrices with two sediment concentrations (0.5, and 5 g/L), two temperatures (12 and 25 °C), and two electrical conductivities (130 and 1300 μS/cm). Kinetic parameters were calculated using a first-order decay model to estimate phage persistence. Both plaque assays and real-time PCR (qPCR) revealed longer phage persistence at 12 °C than at 25 °C. High sediment concentrations accelerated the decay of both infectious phages and nucleic acids, particularly at 25 °C. High electrical conductivity (1300 μS/cm) exerted a protective effect on PP7 at 25 °C, preserving infectivity and RNA integrity, while it had no impact on P22 persistence. P22 DNA persisted longer than infectious P22, whereas PP7 RNA exhibited similar behavior to infectious PP7. Manual resuspension of sediments resulted in only minor recovery of phages. The results suggest that both sediment and water chemistry must be considered when monitoring enteric viruses in aquatic environments. Additionally, qPCR-based approaches may be useful for studying RNA viruses, especially for viruses that are difficult or impossible to culture, providing complementary information on viral genome stability. However, for DNA viruses, combining culture-based and molecular assays is recommended to better understand decay patterns of both infectious particles and viral genomes. These findings, although limited to virus surrogates in synthetic water matrices, have important implications for designing monitoring strategies to control waterborne viral transmission.
{"title":"Infectivity and nucleic acid persistence of P22 and PP7 virus surrogates in synthetic water matrices under different environmental conditions","authors":"S.N. Corimayo , M.N. Maidana Kulesza , D. Gutiérrez-Cacciabue , V.B. Rajal , H.R. Poma","doi":"10.1016/j.jconhyd.2025.104825","DOIUrl":"10.1016/j.jconhyd.2025.104825","url":null,"abstract":"<div><div>The persistence of waterborne virus persistence in surface waters may pose a risk to human health. To assess their persistence and mitigate exposure risks in aquatic environments is essential to understand how they (or their surrogates) interact with suspended sediments under different environmental conditions. These sediment particles can adsorb viral particles, influencing their transport, sedimentation, and persistence in aquatic environments. This study evaluated the decay of two virus surrogates, P22 (DNA phage) and PP7 (RNA phage), for enteric DNA and RNA viruses, respectively, in water environments. The phages decay was analyzed using synthetic water matrices with two sediment concentrations (0.5, and 5 g/L), two temperatures (12 and 25 °C), and two electrical conductivities (130 and 1300 μS/cm). Kinetic parameters were calculated using a first-order decay model to estimate phage persistence. Both plaque assays and real-time PCR (qPCR) revealed longer phage persistence at 12 °C than at 25 °C. High sediment concentrations accelerated the decay of both infectious phages and nucleic acids, particularly at 25 °C. High electrical conductivity (1300 μS/cm) exerted a protective effect on PP7 at 25 °C, preserving infectivity and RNA integrity, while it had no impact on P22 persistence. P22 DNA persisted longer than infectious P22, whereas PP7 RNA exhibited similar behavior to infectious PP7. Manual resuspension of sediments resulted in only minor recovery of phages. The results suggest that both sediment and water chemistry must be considered when monitoring enteric viruses in aquatic environments. Additionally, qPCR-based approaches may be useful for studying RNA viruses, especially for viruses that are difficult or impossible to culture, providing complementary information on viral genome stability. However, for DNA viruses, combining culture-based and molecular assays is recommended to better understand decay patterns of both infectious particles and viral genomes. These findings, although limited to virus surrogates in synthetic water matrices, have important implications for designing monitoring strategies to control waterborne viral transmission.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104825"},"PeriodicalIF":4.4,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145911798","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 : 2025-12-23DOI: 10.1016/j.jconhyd.2025.104824
Paolo Pastorino, Damià Barceló, Christian Griebler
Micro(nano)plastics (MNPs) have been detected in every environmental compartment, yet most research still focused on marine systems. Although freshwater environments are key pathways for the transport of plastics from land to sea, they remained comparatively underexplored. This Virtual Special Issue (VSI) of Journal of Contaminant Hydrology, titled "Microplastics in freshwater systems: occurrence and effects", partly fills this gap by gathering 45 contributions (30 research articles and 15 reviews) from across the globe. Together, the VSI provides a comprehensive view of MNP occurrence, transport, fate, and ecotoxicological effects in various freshwater habitats, including estuary ecosystems. The collected manuscripts highlight advances in analytical methods, modeling, and mitigation strategies, while identifying major knowledge gaps such as limited long-term data sets, methodological inconsistencies, and scarce field-based ecotoxicological studies. This VSI underscores the need for standardized quantification methods, interdisciplinary approaches, and stronger links between science and policy to support effective management of plastic pollution in freshwater systems.
{"title":"Microplastics in freshwater systems: Occurrence and effects.","authors":"Paolo Pastorino, Damià Barceló, Christian Griebler","doi":"10.1016/j.jconhyd.2025.104824","DOIUrl":"https://doi.org/10.1016/j.jconhyd.2025.104824","url":null,"abstract":"<p><p>Micro(nano)plastics (MNPs) have been detected in every environmental compartment, yet most research still focused on marine systems. Although freshwater environments are key pathways for the transport of plastics from land to sea, they remained comparatively underexplored. This Virtual Special Issue (VSI) of Journal of Contaminant Hydrology, titled \"Microplastics in freshwater systems: occurrence and effects\", partly fills this gap by gathering 45 contributions (30 research articles and 15 reviews) from across the globe. Together, the VSI provides a comprehensive view of MNP occurrence, transport, fate, and ecotoxicological effects in various freshwater habitats, including estuary ecosystems. The collected manuscripts highlight advances in analytical methods, modeling, and mitigation strategies, while identifying major knowledge gaps such as limited long-term data sets, methodological inconsistencies, and scarce field-based ecotoxicological studies. This VSI underscores the need for standardized quantification methods, interdisciplinary approaches, and stronger links between science and policy to support effective management of plastic pollution in freshwater systems.</p>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":" ","pages":"104824"},"PeriodicalIF":4.4,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145889252","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}