Pub Date : 2026-02-01DOI: 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":"10.1016/j.jconhyd.2026.104879","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104879"},"PeriodicalIF":4.4,"publicationDate":"2026-02-01","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.2026.104874
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.2026.104864
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.2026.104878
Xiuzhen Nie , Diwen Sun , Xiang Long , Jiayi Tian , Xiaofeng Wen , Zixiang Chen , Yiming Qiu , Yawen Wang , Jiachi Shen , Yu Cai , Lingshi Yin
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":"10.1016/j.jconhyd.2026.104878","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104878"},"PeriodicalIF":4.4,"publicationDate":"2026-02-01","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 : 2026-02-01DOI: 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}
Pub Date : 2026-02-01DOI: 10.1016/j.jconhyd.2026.104865
Yuta Fukatsu , Tomomi Oguri , Takafumi Hamamoto , Keisuke Ishida , Andrew Martin , Yukio Tachi
For long-term safety assessments of deep geological disposal, evaluating effective diffusion coefficients (De) and distribution coefficients (Kd) under in-situ conditions remains a critical yet challenging task due to practical limitations. This study aims to establish a methodology for evaluating these parameters under realistic geological conditions through an integrated analysis of a long-term in-situ diffusion (LTD-II) experiment and complementary laboratory through-diffusion experiments in Grimsel granodiorite. The proposed approach combines (i) post analysis of cored samples to characterize spatial variations in pore connectivity and anisotropic transport, (ii) numerical modeling that accounts for the borehole disturbed zone (BDZ), and (iii) laboratory diffusion experiments to verify the consistency and reliability of in-situ parameter estimation.
The modeling reproduced both the depletion curves and the tracer concentration profiles observed in the LTD-II experiment, particularly the sharp gradients within a few millimeters from the injection hole, which were attributed to BDZ. The derived De and Kd values for sorbing tracers (Na+, Cs+, and Ba2+) were consistent between laboratory and in-situ conditions for transport distances up to several centimeters, confirming the reliability of the parameter derivation approach for sorbing species over short distances. In contrast, non-sorbing tracers (HTO and 36Cl−) exhibited depth-dependent concentration variations extending ∼50 cm from the injection hole. The De values of non-sorbing tracers were two to three times higher than those obtained in laboratory tests, yet remained within the same order of magnitude. These variations of non-sorbing tracers could be qualitatively explained by anisotropic transport along foliation and minor advection over several tens of centimeters, highlighting the importance of accounting for local structural and hydraulic variations when interpreting in-situ diffusion data.
These results demonstrate that integrating in-situ diffusion data with laboratory verification and spatial profiling provides a methodology for deriving diffusion and sorption parameters representative of in-situ conditions, and clarifies the practical limitations and applicable range of transport modeling in crystalline rocks.
{"title":"Methodology for evaluating matrix diffusion and sorption parameters in crystalline rocks: Application to laboratory and in-situ diffusion experiments at the Grimsel Test Site","authors":"Yuta Fukatsu , Tomomi Oguri , Takafumi Hamamoto , Keisuke Ishida , Andrew Martin , Yukio Tachi","doi":"10.1016/j.jconhyd.2026.104865","DOIUrl":"10.1016/j.jconhyd.2026.104865","url":null,"abstract":"<div><div>For long-term safety assessments of deep geological disposal, evaluating effective diffusion coefficients (<em>D</em><sub>e</sub>) and distribution coefficients (<em>K</em><sub>d</sub>) under in-situ conditions remains a critical yet challenging task due to practical limitations. This study aims to establish a methodology for evaluating these parameters under realistic geological conditions through an integrated analysis of a long-term in-situ diffusion (LTD-II) experiment and complementary laboratory through-diffusion experiments in Grimsel granodiorite. The proposed approach combines (i) post analysis of cored samples to characterize spatial variations in pore connectivity and anisotropic transport, (ii) numerical modeling that accounts for the borehole disturbed zone (BDZ), and (iii) laboratory diffusion experiments to verify the consistency and reliability of in-situ parameter estimation.</div><div>The modeling reproduced both the depletion curves and the tracer concentration profiles observed in the LTD-II experiment, particularly the sharp gradients within a few millimeters from the injection hole, which were attributed to BDZ. The derived <em>D</em><sub>e</sub> and <em>K</em><sub>d</sub> values for sorbing tracers (Na<sup>+</sup>, Cs<sup>+</sup>, and Ba<sup>2+</sup>) were consistent between laboratory and in-situ conditions for transport distances up to several centimeters, confirming the reliability of the parameter derivation approach for sorbing species over short distances. In contrast, non-sorbing tracers (HTO and <sup>36</sup>Cl<sup>−</sup>) exhibited depth-dependent concentration variations extending ∼50 cm from the injection hole. The <em>D</em><sub>e</sub> values of non-sorbing tracers were two to three times higher than those obtained in laboratory tests, yet remained within the same order of magnitude. These variations of non-sorbing tracers could be qualitatively explained by anisotropic transport along foliation and minor advection over several tens of centimeters, highlighting the importance of accounting for local structural and hydraulic variations when interpreting in-situ diffusion data.</div><div>These results demonstrate that integrating in-situ diffusion data with laboratory verification and spatial profiling provides a methodology for deriving diffusion and sorption parameters representative of in-situ conditions, and clarifies the practical limitations and applicable range of transport modeling in crystalline rocks.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104865"},"PeriodicalIF":4.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073940","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.2026.104870
Chunlu Jiang , Yuqun Zhang , Qianqian Wang
Groundwater discharge and associated dissolved carbon fluxes are essential parameters in wetland ecosystems of coal mining subsidence lakes. Previous studies have shown that groundwater discharge considerably contributes to isolated coal mining subsidence lakes. However, groundwater discharge and associated dissolved inorganic carbon (DIC) flux into open-type subsidence lakes remain poorly understood. In this study, radioactive (222Rn) and stable water isotopes (18O) were used as tracers to establish isotope mass balance models, and to quantify groundwater discharge into an open-type coal mining subsidence lake. The results showed that the estimated lacustrine groundwater discharge (LGD) rates using the 222Rn and 18O mass balance models were 38.54 ± 21.05 mm/d and 27.89 ± 3.53 mm/d, respectively, which accounted for 15.56% and 12.30% of the total source of lake water. On this basis, combined with a DIC end-member mixing model and CO2 diffusion model, DIC flux from LGD was 70.33 ± 1.41 mmol/(m2·d), accounting for 19.10% of the total lake DIC inventory and 65.60% of the total CO2 evasion from the lake. The results suggest that CO2 escape from freshwater lakes may be an important source of atmospheric carbon, which should be included in the carbon budget of lake budgets. The results provide a theoretical basis for accurate assessment of groundwater discharge and the carbon budget in open-type subsidence lakes. This is important for local water environment protection and the utilization of water resources.
{"title":"Groundwater discharge and dissolved inorganic carbon flux into an open-type coal mining subsidence lake in eastern China","authors":"Chunlu Jiang , Yuqun Zhang , Qianqian Wang","doi":"10.1016/j.jconhyd.2026.104870","DOIUrl":"10.1016/j.jconhyd.2026.104870","url":null,"abstract":"<div><div>Groundwater discharge and associated dissolved carbon fluxes are essential parameters in wetland ecosystems of coal mining subsidence lakes. Previous studies have shown that groundwater discharge considerably contributes to isolated coal mining subsidence lakes. However, groundwater discharge and associated dissolved inorganic carbon (DIC) flux into open-type subsidence lakes remain poorly understood. In this study, radioactive (<sup>222</sup>Rn) and stable water isotopes (<sup>18</sup>O) were used as tracers to establish isotope mass balance models, and to quantify groundwater discharge into an open-type coal mining subsidence lake. The results showed that the estimated lacustrine groundwater discharge (LGD) rates using the <sup>222</sup>Rn and <sup>18</sup>O mass balance models were 38.54 ± 21.05 mm/d and 27.89 ± 3.53 mm/d, respectively, which accounted for 15.56% and 12.30% of the total source of lake water. On this basis, combined with a DIC end-member mixing model and CO<sub>2</sub> diffusion model, DIC flux from LGD was 70.33 ± 1.41 mmol/(m<sup>2</sup>·d), accounting for 19.10% of the total lake DIC inventory and 65.60% of the total CO<sub>2</sub> evasion from the lake. The results suggest that CO<sub>2</sub> escape from freshwater lakes may be an important source of atmospheric carbon, which should be included in the carbon budget of lake budgets. The results provide a theoretical basis for accurate assessment of groundwater discharge and the carbon budget in open-type subsidence lakes. This is important for local water environment protection and the utilization of water resources.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104870"},"PeriodicalIF":4.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073935","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.2026.104853
Gholamheidari Hamideh , Entezari Mojgan
Using a machine learning framework, this study investigates the spatial distribution and key environmental factors of heavy metal contamination (iron, nickel, lead, copper) in four groundwater aquifers of Isfahan province during the water year 2023–2024. A total of 150 wells were sampled and metal concentrations were determined using ICP-MS, AAS, VGA, and Mercury Analyzer methods in accordance with WHO and Iranian standards. The maximum observed concentrations of iron, nickel, lead and copper were approximately 48, 44.1, 2.9 and 11.2 mg/L respectively, with the peak concentrations of iron and copper in the Damaneh - Daran aquifers, nickel in Bouin and lead in Chadegan. Random Forest (RF) and Support Vector Machine (SVM) models were used, and in RF, 100 trees were used for accurate predictions. Multiple collinearity between environmental predictors, including soil properties, unsaturated and saturated zones, hydraulic parameters, slope, groundwater level, and aquifer depth was assessed through variance inflation factor (VIF), all of which were below 10. Model interpretation showed that soil properties and groundwater level had the greatest influence in RF, while the unsaturated layer was dominant in SVM. Iron decreased with increasing aquifer depth, pore thickness, and water table, while soil permeability and slope increased iron accumulation. Nickel was higher in shallow, shallow, and low-conductivity areas, while lead increased with depth and slope, indicating a nonlinear dependence on hydraulic and soil properties. Copper was positively correlated with soil permeability and negatively correlated with water table. Spatial predictions showed that the Bouin aquifer showed the highest iron and nickel (more than 40 and more than 30 mg/L), lead reached about 44 mg/L in Chadegan, and copper peaked in Bouin from southeast to northwest. RF outperformed SVM by achieving an accuracy of 0.7874, sensitivity of 0.7448, and specificity of 0.8243, while SVM performed poorly. This study innovatively combines machine learning models with the parameters of the DRASTIC analytical model to assess and predict heavy metal contamination in the aquifers of Isfahan province. Overall, the results confirm the nonlinear hydrogeological controls on heavy metal distribution and demonstrate the high capability of RF for reliable prediction of groundwater contamination. This approach provides a transferable method for groundwater quality assessment and supports sustainable aquifer management in arid and semi-arid regions.
{"title":"Assessment of groundwater vulnerability to heavy metals in four aquifers using machine learning algorithms","authors":"Gholamheidari Hamideh , Entezari Mojgan","doi":"10.1016/j.jconhyd.2026.104853","DOIUrl":"10.1016/j.jconhyd.2026.104853","url":null,"abstract":"<div><div>Using a machine learning framework, this study investigates the spatial distribution and key environmental factors of heavy metal contamination (iron, nickel, lead, copper) in four groundwater aquifers of Isfahan province during the water year 2023–2024. A total of 150 wells were sampled and metal concentrations were determined using ICP-MS, AAS, VGA, and Mercury Analyzer methods in accordance with WHO and Iranian standards. The maximum observed concentrations of iron, nickel, lead and copper were approximately 48, 44.1, 2.9 and 11.2 mg/L respectively, with the peak concentrations of iron and copper in the Damaneh - Daran aquifers, nickel in Bouin and lead in Chadegan. Random Forest (RF) and Support Vector Machine (SVM) models were used, and in RF, 100 trees were used for accurate predictions. Multiple collinearity between environmental predictors, including soil properties, unsaturated and saturated zones, hydraulic parameters, slope, groundwater level, and aquifer depth was assessed through variance inflation factor (VIF), all of which were below 10. Model interpretation showed that soil properties and groundwater level had the greatest influence in RF, while the unsaturated layer was dominant in SVM. Iron decreased with increasing aquifer depth, pore thickness, and water table, while soil permeability and slope increased iron accumulation. Nickel was higher in shallow, shallow, and low-conductivity areas, while lead increased with depth and slope, indicating a nonlinear dependence on hydraulic and soil properties. Copper was positively correlated with soil permeability and negatively correlated with water table. Spatial predictions showed that the Bouin aquifer showed the highest iron and nickel (more than 40 and more than 30 mg/L), lead reached about 44 mg/L in Chadegan, and copper peaked in Bouin from southeast to northwest. RF outperformed SVM by achieving an accuracy of 0.7874, sensitivity of 0.7448, and specificity of 0.8243, while SVM performed poorly. This study innovatively combines machine learning models with the parameters of the DRASTIC analytical model to assess and predict heavy metal contamination in the aquifers of Isfahan province. Overall, the results confirm the nonlinear hydrogeological controls on heavy metal distribution and demonstrate the high capability of RF for reliable prediction of groundwater contamination. This approach provides a transferable method for groundwater quality assessment and supports sustainable aquifer management in arid and semi-arid regions.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"277 ","pages":"Article 104853"},"PeriodicalIF":4.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146119118","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号