Pub Date : 2026-02-04DOI: 10.1016/j.jconhyd.2026.104876
Chaoqi Wang, Zhi Dou, Ning Chen, Yan Zhu, Zhihan Zou, Jian Song, Shen-Huan Lyu
Pump-and-treat (P&T) remediation is a widely adopted and effective method for groundwater contamination control. It is important to optimize the operation schemes (pumping well locations and pumping rates) to maximize contaminant removal efficiency and minimize operational costs. Recently, surrogate models have been integrated with optimization algorithms to formulate the remediation schemes. However, with various surrogate techniques available, their comparative performance in P&T remediation tasks and potential for combined usage of multiple surrogates require further exploration. In this study, five popular surrogate models-Kriging, Polynomial Interpolation, Support Vector Regression (SVR), Random Forest (RF), and Deep Neural Network (DNN)-were evaluated for their ability to predict contaminant removal efficiency under diverse schemes in a multi-contaminant site. The analysis revealed that, while DNN achieved the highest overall prediction accuracy in the validation stage across the 200 cases, no single surrogate model consistently outperformed the others in all individual cases. A multi-surrogate optimization framework, coupling all five models with a genetic algorithm, was developed to enhance P&T schemes. The usage of multiple surrogates finally brings benefits because the complementary strengths of diverse surrogate models are combined. We identified remediation schemes that achieved superior contaminant removal (17.5% residual contaminant) compared to the other results (19.2-21.7%). The framework offers a robust tool for environmental management and insights for advancing studies related to surrogate-based optimization.
{"title":"A multiple surrogate simulation-optimization framework for designing pump-and-treat systems.","authors":"Chaoqi Wang, Zhi Dou, Ning Chen, Yan Zhu, Zhihan Zou, Jian Song, Shen-Huan Lyu","doi":"10.1016/j.jconhyd.2026.104876","DOIUrl":"https://doi.org/10.1016/j.jconhyd.2026.104876","url":null,"abstract":"<p><p>Pump-and-treat (P&T) remediation is a widely adopted and effective method for groundwater contamination control. It is important to optimize the operation schemes (pumping well locations and pumping rates) to maximize contaminant removal efficiency and minimize operational costs. Recently, surrogate models have been integrated with optimization algorithms to formulate the remediation schemes. However, with various surrogate techniques available, their comparative performance in P&T remediation tasks and potential for combined usage of multiple surrogates require further exploration. In this study, five popular surrogate models-Kriging, Polynomial Interpolation, Support Vector Regression (SVR), Random Forest (RF), and Deep Neural Network (DNN)-were evaluated for their ability to predict contaminant removal efficiency under diverse schemes in a multi-contaminant site. The analysis revealed that, while DNN achieved the highest overall prediction accuracy in the validation stage across the 200 cases, no single surrogate model consistently outperformed the others in all individual cases. A multi-surrogate optimization framework, coupling all five models with a genetic algorithm, was developed to enhance P&T schemes. The usage of multiple surrogates finally brings benefits because the complementary strengths of diverse surrogate models are combined. We identified remediation schemes that achieved superior contaminant removal (17.5% residual contaminant) compared to the other results (19.2-21.7%). The framework offers a robust tool for environmental management and insights for advancing studies related to surrogate-based optimization.</p>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"104876"},"PeriodicalIF":4.4,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146137615","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 widespread presence of microplastics in edible aquatic organisms has attracted considerable global attention, Thus, determining the level of microplastic pollution levels is crucial for ensuring dietary safety. In this study, we investigated microplastic contamination across four aquaculture modes (pond, lake, ecological, and facility) and four aquaculture species (fish, prawn, crab, and swamp eel) in the Dongting Lake area, which is a major region aquaculture area in China. The average abundance of microplastics in the aquaculture water in Dongting Lake was 11.58 ± 3.28 items/L. The pollution level was significantly higher in the swamp eel pond than in the fish, prawn and crab ponds. Integrated wetland purification and high-efficiency water treatment systems in ecological and facility fisheries exhibited significantly lower microplastic abundance compared to traditional aquaculture modes; however, a high concentration of microplastics were detected in the tailwater. These results indicate that the microplastic pollution characteristics across aquaculture systems are influenced by cultured species and operational modes. The implementation of ecological or management measures may be effective in reducing microplastic pollution levels. Our results provide a foundation for assessing microplastic contamination in fisheries and for developing management and remediation strategies.
{"title":"Variations in microplastic pollution characteristics among different aquaculture modes: A case study from Dongting Lake area, China.","authors":"Xiuzhen Nie, Diwen Sun, Xiang Long, Jiayi Tian, Xiaofeng Wen, Zixiang Chen, Yiming Qiu, Yawen Wang, Jiachi Shen, Yu Cai, Lingshi Yin","doi":"10.1016/j.jconhyd.2026.104878","DOIUrl":"https://doi.org/10.1016/j.jconhyd.2026.104878","url":null,"abstract":"<p><p>The widespread presence of microplastics in edible aquatic organisms has attracted considerable global attention, Thus, determining the level of microplastic pollution levels is crucial for ensuring dietary safety. In this study, we investigated microplastic contamination across four aquaculture modes (pond, lake, ecological, and facility) and four aquaculture species (fish, prawn, crab, and swamp eel) in the Dongting Lake area, which is a major region aquaculture area in China. The average abundance of microplastics in the aquaculture water in Dongting Lake was 11.58 ± 3.28 items/L. The pollution level was significantly higher in the swamp eel pond than in the fish, prawn and crab ponds. Integrated wetland purification and high-efficiency water treatment systems in ecological and facility fisheries exhibited significantly lower microplastic abundance compared to traditional aquaculture modes; however, a high concentration of microplastics were detected in the tailwater. These results indicate that the microplastic pollution characteristics across aquaculture systems are influenced by cultured species and operational modes. The implementation of ecological or management measures may be effective in reducing microplastic pollution levels. Our results provide a foundation for assessing microplastic contamination in fisheries and for developing management and remediation strategies.</p>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"104878"},"PeriodicalIF":4.4,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146142588","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 : 2026-02-02DOI: 10.1016/j.jconhyd.2026.104880
Junhao Li, Bowen Yu, Chengjin Cao, Liuxing Wu, Yaping Zhao, Ruiyun Zhu, Yangyang Hu, Minsheng Huang, Lei Wang, Xinlin Yan
Urban stormwater runoff is a critical pathway for microplastics pollution, yet its detailed transport dynamics remain poorly characterized. This study employed intra-event time-series sampling (at intervals of 0, 5, 15, 30, 60, 120, and 240 min after runoff initiation) during a heavy rainfall event in Shanghai (China) to investigate microplastics concentrations and characteristics across three urban functional areas. Our results revealed that microplastic pollution levels were strongly land-use-dependent: the dining area was a severe hotspot, with a time-weighted average concentration of 689.7 ± 214.1 items/L, which was significantly higher than the residential area (215.6 ± 38.9 items/L) and the parking area (172.8 ± 18.8 items/L), and all concentrations far exceeded local aquatic background values. A pronounced first flush effect was observed, particularly in the dining area, where the peak concentration was reached within just 5 min. The runoff was dominated by small-sized (<1.0 mm) and fibrous microplastics composed of PET and PP. These small fibers were preferentially exported in the early phase of runoff (within the first 30 min), whereas granules and larger-sized microplastics accumulated in the later phase. By elucidating the land-use-dependent transport dynamics and fate of microplastics, this study provides a scientific basis for targeted source control, including prioritizing initial flush interception, and stormwater management in global megacities.
{"title":"Spatiotemporal dynamics of microplastics in urban stormwater runoff: Functional area effects and transport pathways (Shanghai, China).","authors":"Junhao Li, Bowen Yu, Chengjin Cao, Liuxing Wu, Yaping Zhao, Ruiyun Zhu, Yangyang Hu, Minsheng Huang, Lei Wang, Xinlin Yan","doi":"10.1016/j.jconhyd.2026.104880","DOIUrl":"https://doi.org/10.1016/j.jconhyd.2026.104880","url":null,"abstract":"<p><p>Urban stormwater runoff is a critical pathway for microplastics pollution, yet its detailed transport dynamics remain poorly characterized. This study employed intra-event time-series sampling (at intervals of 0, 5, 15, 30, 60, 120, and 240 min after runoff initiation) during a heavy rainfall event in Shanghai (China) to investigate microplastics concentrations and characteristics across three urban functional areas. Our results revealed that microplastic pollution levels were strongly land-use-dependent: the dining area was a severe hotspot, with a time-weighted average concentration of 689.7 ± 214.1 items/L, which was significantly higher than the residential area (215.6 ± 38.9 items/L) and the parking area (172.8 ± 18.8 items/L), and all concentrations far exceeded local aquatic background values. A pronounced first flush effect was observed, particularly in the dining area, where the peak concentration was reached within just 5 min. The runoff was dominated by small-sized (<1.0 mm) and fibrous microplastics composed of PET and PP. These small fibers were preferentially exported in the early phase of runoff (within the first 30 min), whereas granules and larger-sized microplastics accumulated in the later phase. By elucidating the land-use-dependent transport dynamics and fate of microplastics, this study provides a scientific basis for targeted source control, including prioritizing initial flush interception, and stormwater management in global megacities.</p>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"104880"},"PeriodicalIF":4.4,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146125122","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 : 2026-02-02DOI: 10.1016/j.jconhyd.2026.104879
Chao Jin, Wei Ma, Peichen Zhang, Shunxin Feng, Yunfei Wang
Extreme weather events, including heatwaves, cold waves, and strong winds, significantly impact lake thermal stratification and aquatic ecosystem stability. This study applied the Environmental Fluid Dynamics Code (EFDC) hydrodynamic-thermal model to analyze the thermal stratification characteristics of Lake Fuxian and its response to extreme weather. The results indicate that the stratification period spans from March to December, with the mixed layer depth (MLD) varying between 6.86 m and 9.89 m in spring and summer, and deepening to 47.7 m in autumn and winter. Extreme heat compresses the MLD and increases surface temperature by 1.59 °C, while strong winds deepen the MLD, causing cooling at the surface and warming at greater depths. Cold waves slightly reduce the mixed-layer temperature and weaken the thermocline. Air temperature, solar radiation, and wind-driven turbulence jointly control the vertical temperature distribution, with wind-driven circulation playing a key role in surface temperature heterogeneity. These findings highlight the need for adaptive management strategies, such as adjusting water intake depths during heatwaves and enhancing monitoring during extreme weather events, to protect aquatic ecosystems under climate change.
{"title":"Thermal stratification characteristics of a deep plateau lake and its response to extreme weather: A case study of Fuxian Lake.","authors":"Chao Jin, Wei Ma, Peichen Zhang, Shunxin Feng, Yunfei Wang","doi":"10.1016/j.jconhyd.2026.104879","DOIUrl":"https://doi.org/10.1016/j.jconhyd.2026.104879","url":null,"abstract":"<p><p>Extreme weather events, including heatwaves, cold waves, and strong winds, significantly impact lake thermal stratification and aquatic ecosystem stability. This study applied the Environmental Fluid Dynamics Code (EFDC) hydrodynamic-thermal model to analyze the thermal stratification characteristics of Lake Fuxian and its response to extreme weather. The results indicate that the stratification period spans from March to December, with the mixed layer depth (MLD) varying between 6.86 m and 9.89 m in spring and summer, and deepening to 47.7 m in autumn and winter. Extreme heat compresses the MLD and increases surface temperature by 1.59 °C, while strong winds deepen the MLD, causing cooling at the surface and warming at greater depths. Cold waves slightly reduce the mixed-layer temperature and weaken the thermocline. Air temperature, solar radiation, and wind-driven turbulence jointly control the vertical temperature distribution, with wind-driven circulation playing a key role in surface temperature heterogeneity. These findings highlight the need for adaptive management strategies, such as adjusting water intake depths during heatwaves and enhancing monitoring during extreme weather events, to protect aquatic ecosystems under climate change.</p>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"104879"},"PeriodicalIF":4.4,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146142652","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 : 2026-02-01DOI: 10.1016/j.jconhyd.2026.104868
Bowen Wang, Sotheavuth Sin, Wilson Susanto, Shintaro Matsushita, Tetsuya Suekane
Hydrogen peroxide (H2O2)-based in situ chemical oxidation (ISCO) is a commonly applied technique for remediating groundwater contaminated by dense non-aqueous phase liquids (DNAPL) such as trichloroethylene (TCE). However, the overall remediation efficiency is often constrained by oxidant self-decomposition and gas-induced pore blockage, which hinder oxidant accessibility to contaminants. To improve the remediation performance, this study experimentally investigated three optimization strategies: follow-up water injection, chemical stabilization, and staged oxidant injection. These three strategies aim to remobilize trapped phases and restore oxidant access, directly suppress H2O2 self-decomposition by introducing a stabilizer, and reintroduce fresh oxidant to reboot the oxidation process, respectively. The pore-scale remediation processes were visualized using time-resolved three-dimensional micro-computed tomography (3D micro-CT) to quantify the spatial and temporal evolution of TCE and gas phases in porous media. Results show that the combined strategy of follow-up water injection and stabilizer achieved a significant enhancement in overall TCE remediation under 5 wt% H2O2 condition, obtaining the highest TCE removal of 78.7%. This study provides direct mechanistic evidence of how physical and chemical measures can jointly enhance oxidant delivery during the remediation process. The pore-scale insights offer guidance for optimizing oxidant management and injection strategies in groundwater environments, and highlight the need to consider gas-liquid-DNAPL interactions when designing field-scale remediation systems.
{"title":"Pore-scale optimization of H2O2-based TCE remediation using stabilizer-enhanced oxidant delivery and follow-up water injection","authors":"Bowen Wang, Sotheavuth Sin, Wilson Susanto, Shintaro Matsushita, Tetsuya Suekane","doi":"10.1016/j.jconhyd.2026.104868","DOIUrl":"10.1016/j.jconhyd.2026.104868","url":null,"abstract":"<div><div>Hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>)-based in situ chemical oxidation (ISCO) is a commonly applied technique for remediating groundwater contaminated by dense non-aqueous phase liquids (DNAPL) such as trichloroethylene (TCE). However, the overall remediation efficiency is often constrained by oxidant self-decomposition and gas-induced pore blockage, which hinder oxidant accessibility to contaminants. To improve the remediation performance, this study experimentally investigated three optimization strategies: follow-up water injection, chemical stabilization, and staged oxidant injection. These three strategies aim to remobilize trapped phases and restore oxidant access, directly suppress H<sub>2</sub>O<sub>2</sub> self-decomposition by introducing a stabilizer, and reintroduce fresh oxidant to reboot the oxidation process, respectively. The pore-scale remediation processes were visualized using time-resolved three-dimensional micro-computed tomography (3D micro-CT) to quantify the spatial and temporal evolution of TCE and gas phases in porous media. Results show that the combined strategy of follow-up water injection and stabilizer achieved a significant enhancement in overall TCE remediation under 5 wt% H<sub>2</sub>O<sub>2</sub> condition, obtaining the highest TCE removal of 78.7%. This study provides direct mechanistic evidence of how physical and chemical measures can jointly enhance oxidant delivery during the remediation process. The pore-scale insights offer guidance for optimizing oxidant management and injection strategies in groundwater environments, and highlight the need to consider gas-liquid-DNAPL interactions when designing field-scale remediation systems.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104868"},"PeriodicalIF":4.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073936","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 : 2026-02-01DOI: 10.1016/j.jconhyd.2026.104864
Mohd Rashidi Abdull Manap , Muhammad Ibadurrahman bin Imizan , Jannik Werner Dams , Felipe D. Sepulveda , Anna Muratore , Lorenza Notargiacomo , Fulvio Ferrara , Nur Hayatna Mukhni
Microplastic (MP) pollution is increasingly recognized as a critical issue in coastal environments, where complex interactions between ocean currents, winds, waves, and human activities govern the transport and deposition of synthetic particles. Although previous studies in Asia have documented MPs accumulation linked to riverine discharge, tourism pressures, and monsoonal circulation, limited work has integrated polymer-level characterization with site-specific hydrodynamic drivers, particularly along the coastlines of Bali. This study addresses this gap by examining how seasonal oceanographic processes influence MPs composition and distribution across three beaches: Keramas Beach (KB), Nyang Nyang Beach (NNB), and Balangan Beach (BB), between January and July 2024. This study provides a baseline, site-specific assessment of microplastic occurrence, polymer composition, and size distribution in three selected beach sediments of Bali, intended to establish reference conditions. Seventeen beach sediments were sampled and processed through dry sieving, microscopy, and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy to identify particle sizes, morphologies, and polymer types. Hydrodynamic conditions were reconstructed using satellite-derived datasets from the Copernicus Marine Environment Monitoring Service (CMEMS) and the Copernicus Atmosphere Monitoring Service (CAMS), alongside estimates of riverine plastic discharge. A total of 10 MP particles (<5 mm) were identified, with polystyrene (PS) as the dominant polymer, followed by polypropylene (PP), polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), and three copolymers. MPs occurred primarily as fragments within the 2.5–5 mm range. The average MP concentrations were 2.54 ± 2.30, 2.04 ± 2.49, and 0.61 ± 1.37 MPs/kg dry weight (dw) at KB, NNB, and BB, respectively, following the order KB > NNB > BB. Spatial variability corresponded closely with hydrodynamic patterns: KB exhibited the highest MP concentration due to onshore winds and southwestward currents from the Lombok Strait; BB showed low retention driven by offshore wind stress and weak currents; and NNB displayed intermediate accumulation influenced by longshore drift and moderate river inputs. These findings highlight the value of integrating spectroscopic analysis with remote-sensing hydrodynamics to explain mechanisms of MP deposition, offering a strengthened basis for targeted monitoring, predictive modeling, and coastal pollution management in Bali and neighboring islands.
{"title":"Microplastics distribution on the beach sediment based on satellite remote sensing: A case study in Bali, Indonesia","authors":"Mohd Rashidi Abdull Manap , Muhammad Ibadurrahman bin Imizan , Jannik Werner Dams , Felipe D. Sepulveda , Anna Muratore , Lorenza Notargiacomo , Fulvio Ferrara , Nur Hayatna Mukhni","doi":"10.1016/j.jconhyd.2026.104864","DOIUrl":"10.1016/j.jconhyd.2026.104864","url":null,"abstract":"<div><div>Microplastic (MP) pollution is increasingly recognized as a critical issue in coastal environments, where complex interactions between ocean currents, winds, waves, and human activities govern the transport and deposition of synthetic particles. Although previous studies in Asia have documented MPs accumulation linked to riverine discharge, tourism pressures, and monsoonal circulation, limited work has integrated polymer-level characterization with site-specific hydrodynamic drivers, particularly along the coastlines of Bali. This study addresses this gap by examining how seasonal oceanographic processes influence MPs composition and distribution across three beaches: Keramas Beach (KB), Nyang Nyang Beach (NNB), and Balangan Beach (BB), between January and July 2024. This study provides a baseline, site-specific assessment of microplastic occurrence, polymer composition, and size distribution in three selected beach sediments of Bali, intended to establish reference conditions. Seventeen beach sediments were sampled and processed through dry sieving, microscopy, and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy to identify particle sizes, morphologies, and polymer types. Hydrodynamic conditions were reconstructed using satellite-derived datasets from the Copernicus Marine Environment Monitoring Service (CMEMS) and the Copernicus Atmosphere Monitoring Service (CAMS), alongside estimates of riverine plastic discharge. A total of 10 MP particles (<5 mm) were identified, with polystyrene (PS) as the dominant polymer, followed by polypropylene (PP), polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), and three copolymers. MPs occurred primarily as fragments within the 2.5–5 mm range. The average MP concentrations were 2.54 ± 2.30, 2.04 ± 2.49, and 0.61 ± 1.37 MPs/kg dry weight (dw) at KB, NNB, and BB, respectively, following the order KB > NNB > BB. Spatial variability corresponded closely with hydrodynamic patterns: KB exhibited the highest MP concentration due to onshore winds and southwestward currents from the Lombok Strait; BB showed low retention driven by offshore wind stress and weak currents; and NNB displayed intermediate accumulation influenced by longshore drift and moderate river inputs. These findings highlight the value of integrating spectroscopic analysis with remote-sensing hydrodynamics to explain mechanisms of MP deposition, offering a strengthened basis for targeted monitoring, predictive modeling, and coastal pollution management in Bali and neighboring islands.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104864"},"PeriodicalIF":4.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146063934","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 : 2026-02-01DOI: 10.1016/j.jconhyd.2026.104874
Anfeng Zhang, Yinglan A, Jingzhi Yu, Jin Wu, Yuntao Wang, Baolin Xue, Kaiji Li, Lei Jin
Estuarine ecosystems play vital roles in sustaining regional biodiversity, water purification, and ecological buffering. However, the resumption of navigation can have a marked effect on ecosystem health through changes in water and sediment conditions. In this study, field measurements and remote sensing data were used to assess the ecological health of the Xiaoqing River estuary following the restoration of navigation. It focused on changes in physicochemical habitat factors and their key drivers affecting phytoplankton, zooplankton, and benthic communities. The findings indicate that the water quality in the estuary gradually improved after restoration of navigation, and mild to -moderate pollution occurred. The water surface area increased and fluctuations decreased. Heavy metal risks still exist in some river mouth areas, with sediment mercury (Hg) and cadmium (Cd) concentrations maintaining mild to moderate levels. Heavy metals are major drivers of aquatic community structures. Zinc (Zn, ), copper (Cu), and Hg strongly influence planktonic assemblages. Phycocyanin (PC, ), cobalt (Co, ), Zn, and organic carbon are key factors for benthic communities. Overall, channel restoration projects have improved water quality and enhanced ecosystem integrity, but risks from residual pollutants persist, necessitating ongoing monitoring and management efforts.
{"title":"The impact of navigation restoration on estuarine aquatic ecosystems: The case of the Xiaoqing River in China","authors":"Anfeng Zhang, Yinglan A, Jingzhi Yu, Jin Wu, Yuntao Wang, Baolin Xue, Kaiji Li, Lei Jin","doi":"10.1016/j.jconhyd.2026.104874","DOIUrl":"10.1016/j.jconhyd.2026.104874","url":null,"abstract":"<div><div>Estuarine ecosystems play vital roles in sustaining regional biodiversity, water purification, and ecological buffering. However, the resumption of navigation can have a marked effect on ecosystem health through changes in water and sediment conditions. In this study, field measurements and remote sensing data were used to assess the ecological health of the Xiaoqing River estuary following the restoration of navigation. It focused on changes in physicochemical habitat factors and their key drivers affecting phytoplankton, zooplankton, and benthic communities. The findings indicate that the water quality in the estuary gradually improved after restoration of navigation, and mild to <span><math><mi>β</mi></math></span>-moderate pollution occurred. The water surface area increased and fluctuations decreased. Heavy metal risks still exist in some river mouth areas, with sediment mercury (Hg) and cadmium (Cd) concentrations maintaining mild to moderate levels. Heavy metals are major drivers of aquatic community structures. Zinc (Zn, <span><math><mrow><mi>p</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>044</mn></mrow></math></span>), copper (Cu), and Hg strongly influence planktonic assemblages. Phycocyanin (PC, <span><math><mrow><mi>p</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>006</mn></mrow></math></span>), cobalt (Co, <span><math><mrow><mi>p</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>04</mn></mrow></math></span>), Zn, and organic carbon are key factors for benthic communities. Overall, channel restoration projects have improved water quality and enhanced ecosystem integrity, but risks from residual pollutants persist, necessitating ongoing monitoring and management efforts.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104874"},"PeriodicalIF":4.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074025","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 : 2026-02-01DOI: 10.1016/j.jconhyd.2026.104860
Damien Costa , Maria A. Stoica , Gladys Foissey , Venceslas Villier , Romain Coppée , Antoine Morel , Romy Razakandrainibe , Loïc Favennec , Philippe Audra , Matthieu Fournier
Cryptosporidium spp. are protozoan parasites worldwide distributed, frequently responsible for gastrointestinal outbreaks from waterborne and foodborne origins. Overall European increase cryptosporidiosis incidence have recently been reported. Aim was to evaluate a specific intrinsic vulnerability mapping method for karst aquifers (PaPRIKa method) for application to Cryptosporidium contamination. Risk zones were mapped using the PaPRIKa vulnerability method enabling identification of sampling sites. From January to July 2021, eight sampling sites were investigated monthly. Cryptosporidium and bacterial contamination were evaluated using standard methods and confronted to water conductivity, turbidity, temperature and precipitation data to investigate potential correlation. Until 87% of sampling sites preselected using the PaPRIKa method were contaminated by Cryptosporidium suggesting the relevance of the method for identifying the most vulnerable sites. Oocysts were infectious in 81% of cases.Water temperature and precipitations influenced Cryptosporidium contamination. In the context of global changes where it is expected increase of waterborne disease, efficient tools to predict Cryptosporidium water resources contamination are mandatory. We suggest use of predictive tool for identification of vulnerable sites to monitor integrating nature of soils, levels of precipitations, soil saturation, land cover, urban waste and rearing areas.
{"title":"Evaluation of the protection of aquifers against pollution risks in karstic areas (PAPRIKA) method for predicting Cryptosporidium contamination","authors":"Damien Costa , Maria A. Stoica , Gladys Foissey , Venceslas Villier , Romain Coppée , Antoine Morel , Romy Razakandrainibe , Loïc Favennec , Philippe Audra , Matthieu Fournier","doi":"10.1016/j.jconhyd.2026.104860","DOIUrl":"10.1016/j.jconhyd.2026.104860","url":null,"abstract":"<div><div><em>Cryptosporidium</em> spp. are protozoan parasites worldwide distributed, frequently responsible for gastrointestinal outbreaks from waterborne and foodborne origins. Overall European increase cryptosporidiosis incidence have recently been reported. Aim was to evaluate a specific intrinsic vulnerability mapping method for karst aquifers (PaPRIKa method) for application to <em>Cryptosporidium</em> contamination. Risk zones were mapped using the PaPRIKa vulnerability method enabling identification of sampling sites. From January to July 2021, eight sampling sites were investigated monthly. <em>Cryptosporidium</em> and bacterial contamination were evaluated using standard methods and confronted to water conductivity, turbidity, temperature and precipitation data to investigate potential correlation. Until 87% of sampling sites preselected using the PaPRIKa method were contaminated by <em>Cryptosporidium</em> suggesting the relevance of the method for identifying the most vulnerable sites. Oocysts were infectious in 81% of cases.Water temperature and precipitations influenced <em>Cryptosporidium</em> contamination. In the context of global changes where it is expected increase of waterborne disease, efficient tools to predict <em>Cryptosporidium</em> water resources contamination are mandatory. We suggest use of predictive tool for identification of vulnerable sites to monitor integrating nature of soils, levels of precipitations, soil saturation, land cover, urban waste and rearing areas.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104860"},"PeriodicalIF":4.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073938","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 : 2026-02-01DOI: 10.1016/j.jconhyd.2026.104867
Honghan Dong , Yun-Min Chen , Wenjie Xu
This study develops a two-dimensional numerical model for seepage and pollutant transport in sites with suspended cutoff walls, grounded in the advection–dispersion equation. The impacts of key factors, including the pressure head of the pollution source, the site's horizontal hydraulic gradient, and the horizontal distance between the downstream wall and the pollution source, on the non-linear seepage distribution and the wall's anti-pollution performance were investigated. Centrifuge model tests were conducted to confirm the numerical model's dependability. Furthermore, the concentration at the downstream wall bottom reaching 10% C0 was established as the threshold for identifying the suspended containment system's failure. The research findings demonstrate that modifications to the site flow field due to parameter changes are a significant factor contributing to the macroscopic variations in pollutant migration. As the pressure head of the pollution source diminishes from 1.2 m to 0.3 m, the peak flow velocity at the mid-point of the liner bottom reduces by 25.6%, while the service life of the wall extends by 51.1%. The site flow-field distribution is significantly impacted, with the wall's service life increasing by 209.1% and 22.8%, respectively, as the site's horizontal hydraulic gradient decreases from 0.04 to 0.01 and the horizontal distance between the downstream wall and the pollution source increases from 4 m to 16 m. Therefore, the design of suspended cutoff walls in risk control of contaminated sites with deeply buried aquitards should focus on aspects related to these three factors.
{"title":"Evaluation of key control factors on pollutant migration by suspended cutoff walls in contaminated sites","authors":"Honghan Dong , Yun-Min Chen , Wenjie Xu","doi":"10.1016/j.jconhyd.2026.104867","DOIUrl":"10.1016/j.jconhyd.2026.104867","url":null,"abstract":"<div><div>This study develops a two-dimensional numerical model for seepage and pollutant transport in sites with suspended cutoff walls, grounded in the advection–dispersion equation. The impacts of key factors, including the pressure head of the pollution source, the site's horizontal hydraulic gradient, and the horizontal distance between the downstream wall and the pollution source, on the non-linear seepage distribution and the wall's anti-pollution performance were investigated. Centrifuge model tests were conducted to confirm the numerical model's dependability. Furthermore, the concentration at the downstream wall bottom reaching 10% <em>C</em><sub>0</sub> was established as the threshold for identifying the suspended containment system's failure. The research findings demonstrate that modifications to the site flow field due to parameter changes are a significant factor contributing to the macroscopic variations in pollutant migration. As the pressure head of the pollution source diminishes from 1.2 m to 0.3 m, the peak flow velocity at the mid-point of the liner bottom reduces by 25.6%, while the service life of the wall extends by 51.1%. The site flow-field distribution is significantly impacted, with the wall's service life increasing by 209.1% and 22.8%, respectively, as the site's horizontal hydraulic gradient decreases from 0.04 to 0.01 and the horizontal distance between the downstream wall and the pollution source increases from 4 m to 16 m. Therefore, the design of suspended cutoff walls in risk control of contaminated sites with deeply buried aquitards should focus on aspects related to these three factors.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104867"},"PeriodicalIF":4.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074024","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 : 2026-02-01DOI: 10.1016/j.jconhyd.2026.104871
Youxiao Wang , Zhaomin Zhang , Zhonghe Zhao , He Li , Yingjun Sun , Chong Huang , Banghua Zhang , Gaohuan Liu
China has been confronted with severe agricultural nonpoint source pollution (AGNSP) from livestock and poultry, which increases chemical oxygen demand (COD). To explore the sources of COD in surface waters from the perspective of ecosystem processes, taking the coastal watershed of the Yellow River Delta (YRD) of China as a typical study area, we have adopted a method that integrates the scale and positioning of livestock and poultry breeding, a pollutant generation coefficient, and kernel density estimation (KDE) to assess the COD diffusion risk during watershed soil erosion processes. Moreover, verification and analysis were performed by combining soil sampling data with hydrological and water quality monitoring data for the estuary. Additionally, we selected Spearman's coefficient for correlation analysis between surface soil organic matter (SOM) and related natural-anthropogenic factors. The main conclusions are as follows: the terrestrial COD pollution risks generated by livestock and poultry significantly influence SOM (p < 0.001) and are most strongly correlated in non-arable lands, especially saline-alkali land (rs = 0.86) mainly because of natural soil erosion process. Arable land has the highest SOM concentrations but has lower correlations with the COD generation risks obtained by the KDE method, mainly because of cultivation activities. At the watershed scale, surface runoff is the dominant driver of estuarine COD fluxes but has certain dilution effects on COD concentrations. Furthermore, there usually exists the spillover effects of AGNSP from livestock and poultry usually occur due to the imbalanced distributions between the area of arable land and the supply of manure within watersheds. Our study provides an effective and rapid assessment method for determining the AGNSP risk of COD derived from livestock and poultry.
{"title":"Tracing coastal nonpoint sources of agricultural organic pollution based on soil sequestration and retention processes: A case study of the Yellow River Delta, China","authors":"Youxiao Wang , Zhaomin Zhang , Zhonghe Zhao , He Li , Yingjun Sun , Chong Huang , Banghua Zhang , Gaohuan Liu","doi":"10.1016/j.jconhyd.2026.104871","DOIUrl":"10.1016/j.jconhyd.2026.104871","url":null,"abstract":"<div><div>China has been confronted with severe agricultural nonpoint source pollution (AGNSP) from livestock and poultry, which increases chemical oxygen demand (COD). To explore the sources of COD in surface waters from the perspective of ecosystem processes, taking the coastal watershed of the Yellow River Delta (YRD) of China as a typical study area, we have adopted a method that integrates the scale and positioning of livestock and poultry breeding, a pollutant generation coefficient, and kernel density estimation (KDE) to assess the COD diffusion risk during watershed soil erosion processes. Moreover, verification and analysis were performed by combining soil sampling data with hydrological and water quality monitoring data for the estuary. Additionally, we selected <em>Spearman's</em> coefficient for correlation analysis between surface soil organic matter (SOM) and related natural-anthropogenic factors. The main conclusions are as follows: the terrestrial COD pollution risks generated by livestock and poultry significantly influence SOM (<em>p</em> < 0.001) and are most strongly correlated in non-arable lands, especially saline-alkali land (<em>r</em><sub><em>s</em></sub> = 0.86) mainly because of natural soil erosion process. Arable land has the highest SOM concentrations but has lower correlations with the COD generation risks obtained by the KDE method, mainly because of cultivation activities. At the watershed scale, surface runoff is the dominant driver of estuarine COD fluxes but has certain dilution effects on COD concentrations. Furthermore, there usually exists the spillover effects of AGNSP from livestock and poultry usually occur due to the imbalanced distributions between the area of arable land and the supply of manure within watersheds. Our study provides an effective and rapid assessment method for determining the AGNSP risk of COD derived from livestock and poultry.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104871"},"PeriodicalIF":4.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073937","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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