Journal of contaminant hydrology最新文献

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Identifying an indicator compound for progress monitoring during in-situ thermal treatment of coal tar and creosote
IF 3.5 3区 环境科学与生态学
Journal of contaminant hydrology Pub Date : 2025-03-09 DOI: 10.1016/j.jconhyd.2025.104543
Liam M. Price, Ariel Nunez Garcia, Kevin G. Mumford
{"title":"Identifying an indicator compound for progress monitoring during in-situ thermal treatment of coal tar and creosote","authors":"Liam M. Price,&nbsp;Ariel Nunez Garcia,&nbsp;Kevin G. Mumford","doi":"10.1016/j.jconhyd.2025.104543","DOIUrl":"10.1016/j.jconhyd.2025.104543","url":null,"abstract":"<div><div>In situ thermal treatment (ISTT) has been used to treat sites impacted by coal tar and creosote when stringent remediation objectives must be met over short timeframes. There is a need to identify an indicator compound that can be used to track progress during the treatment of these complex semi-volatile non-aqueous phase liquids (NAPLs) to complement soil sampling typically conducted once treatment is complete. This study outlines an approach to track ISTT progress and support shutdown decisions based on mass removal objectives using a series of laboratory experiments to investigate changes in semi-volatile NAPL composition during thermal treatment. Sand, water and semi-volatile NAPL were heated, and the recovery of polycyclic aromatic hydrocarbons (PAHs) was monitored by sampling and analysis of condensate. PAHs were predominantly removed between 260 °C and 455 °C, with early-stage condensate composed of higher volatility PAHs and later-stage condensate composed of lower volatility PAHs. Experimental results showed that intermediate-volatility PAHs (e.g., phenanthrene) could be used as an indicator compound to infer treatment progress with respect to both higher and lower volatility PAHs. Monitoring an indicator compound during ISTT of semi-volatile NAPL could provide higher confidence in treatment progress than conventional monitoring techniques and allow for more accurate shutdown decisions.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"271 ","pages":"Article 104543"},"PeriodicalIF":3.5,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143669975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Remediation of toluene-contaminated soils by sequential treatment: Soil vapor extraction systems and internal combustion engine units 通过序贯处理来修复受甲苯污染的土壤:土壤蒸气萃取系统和内燃机装置
IF 3.5 3区 环境科学与生态学
Journal of contaminant hydrology Pub Date : 2025-03-08 DOI: 10.1016/j.jconhyd.2025.104532
Zhengju Lyu, Weilong Zhou, Xiaolong Gao, Haowei Zheng, Jianli Jia
{"title":"Remediation of toluene-contaminated soils by sequential treatment: Soil vapor extraction systems and internal combustion engine units","authors":"Zhengju Lyu,&nbsp;Weilong Zhou,&nbsp;Xiaolong Gao,&nbsp;Haowei Zheng,&nbsp;Jianli Jia","doi":"10.1016/j.jconhyd.2025.104532","DOIUrl":"10.1016/j.jconhyd.2025.104532","url":null,"abstract":"<div><div>This paper reports soil vapor extraction (SVE) systems and internal combustion engine (ICE) units to remediate soils contaminated with toluene. Response surface methodology (RSM) was used to evaluate the influence of toluene concentration, air flow rate and soil water content on SVE systems, thus to identify the optimal conditions for SVE systems. ICE units were used to treat the SVE off-gas extracted from toluene-contaminated soils, and the performance in removing toluene was effectively evaluated. Furthermore, the pulsed operation of SVE systems and the thermal enhancement with ICE off-gas were explored, and the positive effects on remediation efficiency were analyzed. The remediation experiments performed in toluene-contaminated soils allowed concluding that the optimal desorption time of toluene was 615 min with the toluene concentration of 0.3 g/kg, air flow rate of 10 L/min and soil water content of 9 %. The ICE units showed that the main components of ICE off-gas were CO, CO<sub>2</sub> and hydrocarbon (HC). After 25 min, the concentration of HC decreased to 140 ppm, and the volume fractions of CO and CO<sub>2</sub> were 0.3 % and 9.5 % respectively. ICE units had consistently achieved toluene destruction and removal efficiencies (DREs) of 100 %. Moreover, the pulsed operation and thermal enhancement promoted equilibrium partitioning of toluene between the soil matrix and the gas phase, thereby facilitating the desorption of toluene, which decreased the required time and energy needed for the remediation. This study provides theoretical support for system design and applicability assessment of SVE systems and ICE units in the remediation of contaminated soils.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"271 ","pages":"Article 104532"},"PeriodicalIF":3.5,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143628158","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}
引用次数: 0
Assessment of microplastics and heavy metal contamination in surficial sediments of Pasig River, Philippines during wet season
IF 3.5 3区 环境科学与生态学
Journal of contaminant hydrology Pub Date : 2025-03-01 DOI: 10.1016/j.jconhyd.2025.104527
Clarissa Ileana L. Ilao , Joan Cecilia C. Casila , Tonni Agustiono Kurniawan , Ronnie S. Sampang , Lars Lerry T. Panganiban , Liza B. Patacsil , Jomel S. Limbago
{"title":"Assessment of microplastics and heavy metal contamination in surficial sediments of Pasig River, Philippines during wet season","authors":"Clarissa Ileana L. Ilao ,&nbsp;Joan Cecilia C. Casila ,&nbsp;Tonni Agustiono Kurniawan ,&nbsp;Ronnie S. Sampang ,&nbsp;Lars Lerry T. Panganiban ,&nbsp;Liza B. Patacsil ,&nbsp;Jomel S. Limbago","doi":"10.1016/j.jconhyd.2025.104527","DOIUrl":"10.1016/j.jconhyd.2025.104527","url":null,"abstract":"<div><div>This study investigates the contamination of microplastics (MPs) and heavy metals in surficial sediments of the Pasig River, Philippines, during the wet season. This season, marked by heightened rainfall, runoff, and stormwater flow, potentially enhances the dispersion and accumulation of pollutants, leading to elevated pollution levels. MPs and heavy metals pose significant threats to aquatic ecosystems and human health, and their accumulation in river sediments warrants urgent attention. Samples were collected from multiple sites along the river, focusing on sediment composition, to analyze MP abundance and heavy metal concentrations. Results revealed high concentrations of MPs, predominantly polyester, polyethylene and acrylonitrile-butadiene copolymer, and heavy metals which were significantly higher in urbanized areas. MPs were found at all sampling locations, ranging from 2700 to 28,250 particles per kilogram of sediments. Heavy metals in the sediments varied, with concentrations of Cd (&lt;0.003 mg/kg), Pb (3.09–50.48 mg/kg), Zn (53.37–175.74 mg/kg), and Fe (11,629–25,687 mg/kg), in the order Fe &gt; Zn &gt; Pb &gt; Cd. According to the Hong Kong-Interim Sediment Quality Values criteria, the sediments were not contaminated by Cd, Pb, and Zn. Correlations between MP abundance and metals were found to be moderate for Pb and Zn but low for Fe, suggesting complex pollution dynamics. These findings emphasize the need for comprehensive monitoring and targeted waste management strategies to address MPs and heavy metal pollution, particularly during the wet season. Identifying MPs polymer types and their possible pollution sources provides valuable data to mitigate sediment contamination and protect aquatic ecosystems and human health.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"270 ","pages":"Article 104527"},"PeriodicalIF":3.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143510683","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}
引用次数: 0
Pesticide fate under varying cropping systems and soil depths: A study using leaching experiments and inverse modelling.
IF 3.5 3区 环境科学与生态学
Journal of contaminant hydrology Pub Date : 2025-03-01 DOI: 10.1016/j.jconhyd.2025.104526
Clémence Pirlot , Alodie Blondel , Boris Krings , Bastien Durenne , Olivier Pigeon , Aurore Degré
{"title":"Pesticide fate under varying cropping systems and soil depths: A study using leaching experiments and inverse modelling.","authors":"Clémence Pirlot ,&nbsp;Alodie Blondel ,&nbsp;Boris Krings ,&nbsp;Bastien Durenne ,&nbsp;Olivier Pigeon ,&nbsp;Aurore Degré","doi":"10.1016/j.jconhyd.2025.104526","DOIUrl":"10.1016/j.jconhyd.2025.104526","url":null,"abstract":"<div><div>Current pesticide leaching risk assessments overlook critical site-specific factors such as soil depth and agricultural practices. Relying on transport parameters from databases or manufacturer studies, often based on limited soil types, can lead to inaccurate contamination risk estimates and ineffective protection of groundwater resources. In this study, the fate of eight pesticides of concern for groundwater was investigated under three cropping systems and three soil depths. Leaching experiments were carried out in undisturbed columns from a loamy agricultural soil and mass balances were realized. Inverse dual-porosity modelling using Hydrus 1-D was then performed to adjust mobility parameters. The results reveal that different soil properties and structure between soil depths have a more substantial impact on pesticide leaching behaviour than the cropping systems. Significant differences in pesticide transport and retention are observed between soil horizons, illustrating the inadequacy of using surface parameters for the entire soil profile, which can lead to underestimation of groundwater contamination. Our analysis indicates that root architecture, soil properties and surface tillage can affect pesticide leaching dynamics. While short-term differences between cropping systems were limited, these factors could be important for long-term effects. The experimental transport parameters showed discrepancies with established databases, where higher adsorption and degradation could underestimate pesticide leaching and metabolites production. This study highlights the need to adapt transport parameter values for all pesticides of concern to site-specific conditions. In addition, accurate risk assessment requires advanced modelling techniques that take into account soil depth variability and local conditions to improve water protection decision-making. Future research should focus on long-term monitoring of the effects of sustainable agricultural practices on pesticide behaviour over several seasons and for a range of soil types. Special emphasis should be placed on the role of metabolites in environmental contamination.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"270 ","pages":"Article 104526"},"PeriodicalIF":3.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552654","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}
引用次数: 0
A land use regression model to explain the spatial variation of nitrate concentration – A regional scale case study in the north-west of Ireland
IF 3.5 3区 环境科学与生态学
Journal of contaminant hydrology Pub Date : 2025-03-01 DOI: 10.1016/j.jconhyd.2025.104528
Arghadyuti Banerjee, Aonghus Ó'Domhnaill, Leo Creedon, Noelle Jones, Salem Gharbia
{"title":"A land use regression model to explain the spatial variation of nitrate concentration – A regional scale case study in the north-west of Ireland","authors":"Arghadyuti Banerjee,&nbsp;Aonghus Ó'Domhnaill,&nbsp;Leo Creedon,&nbsp;Noelle Jones,&nbsp;Salem Gharbia","doi":"10.1016/j.jconhyd.2025.104528","DOIUrl":"10.1016/j.jconhyd.2025.104528","url":null,"abstract":"<div><div>Regional-scale groundwater contamination estimation is crucial for sustainable water management. The primary obstacles in evaluating groundwater include limited data availability, small sample sizes, and difficulties in linking concentration levels to land use patterns. Linear regression identifies the relationship between measured concentrations and both natural and human-influenced factors. However, the primary difficulty with this method lies in choosing a group of regressors that meet all necessary criteria for the model when multiple potential regressors exist. This study introduces a buffer-based land-use linear regression method to develop a catchment-scale model for predicting nitrate concentrations in groundwater. The model successfully captures 85 % of the spatial variability in nitrate across the study area, as indicated by the validation results from 32 training sites. The model's prediction capability and ability to capture the spatial variability of nitrate concentration were found to be good in the model development (R<sup>2</sup> = 0.89) and validation (R<sup>2</sup> = 0.80) steps. The model performed well in the accuracy assessment and error estimation processes (RMSE = 0.025 and MAE = 0.020). In future, this LUR model can be reparameterised with the latest available time series datasets to capture climate change scenarios. While this study focused on a small sub-catchment of the Bonet River, the methodology has the potential to be applied in a border study area. Future studies with a more robust methodology and more accurate predictor variables to explain the influence of the contamination sources, transport and attenuation processes can improve the buffer-based LUR technique for better model adaptation and applicability to other study areas.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"270 ","pages":"Article 104528"},"PeriodicalIF":3.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Effects of stratification on hydrodynamics and mixing process at a large asymmetric confluence in northern China
IF 3.5 3区 环境科学与生态学
Journal of contaminant hydrology Pub Date : 2025-03-01 DOI: 10.1016/j.jconhyd.2025.104531
Cheng Dong, Minquan Feng, Haixiao Jing, Xiaoge Dang
{"title":"Effects of stratification on hydrodynamics and mixing process at a large asymmetric confluence in northern China","authors":"Cheng Dong,&nbsp;Minquan Feng,&nbsp;Haixiao Jing,&nbsp;Xiaoge Dang","doi":"10.1016/j.jconhyd.2025.104531","DOIUrl":"10.1016/j.jconhyd.2025.104531","url":null,"abstract":"<div><div>The hydrodynamics in the confluence area of rivers are typically governed by the geometrical configuration of the surrounding landforms, the momentum and discharge ratios of the converging watercourses, and the morphological features of the riverbed. Recently, it has been discovered that stratification effects resulting from disparities in temperature, salinity, sediment concentration can also have significant impact on the downstream hydrodynamics of the confluence area. In this study, the impact of stratification induced by sediment concentration on fluid dynamics and pollutant mixing in the Yellow - Fen River confluence area is studied by using a 3D numerical model. The distribution of the depth-averaged field and secondary flow are analyzed. The findings revealed that the alterations in density caused by sediment concentration had effect on the flow dynamics across both horizontal and vertical dimensions of the confluence area. These alterations encompassed flow magnitude, shear layer, low velocity zone, cross-section vortex, and secondary flow. When the sediment concentration in the main stream was high, a noticeable stratification phenomenon emerged, whereby the tributary pollutants rode above the main stream during transport and mixing. Under these conditions, the pollutant mixing process accelerated, resulting in a shortened mixing distance. This acceleration can be attributed to the intensified secondary flow in the cross-section, brought about by the stratification effect. The findings from this study enhance our understanding of pollutant mixing patterns in river confluence areas.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"270 ","pages":"Article 104531"},"PeriodicalIF":3.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143510785","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}
引用次数: 0
Sensitivity analysis of a parameterization of coagulation in an aqueous transport model
IF 3.5 3区 环境科学与生态学
Journal of contaminant hydrology Pub Date : 2025-03-01 DOI: 10.1016/j.jconhyd.2025.104525
Vivian Turner , Madison Bruno , David W. Werth , Robert Buckley
{"title":"Sensitivity analysis of a parameterization of coagulation in an aqueous transport model","authors":"Vivian Turner ,&nbsp;Madison Bruno ,&nbsp;David W. Werth ,&nbsp;Robert Buckley","doi":"10.1016/j.jconhyd.2025.104525","DOIUrl":"10.1016/j.jconhyd.2025.104525","url":null,"abstract":"<div><div>A three-dimensional aqueous transport model, ALGE, was developed at the Savannah River National Laboratory (SRNL) as a tool for emergency response. Recently, coagulation and break-up of suspended sediment and particulate (contaminant adhered to sediment) matter has been added as a new model capability via bilinear interpolation of salinity and turbulence. A sensitivity analysis was performed by comparing time series of suspended sediment and particulate concentrations at various locations when the model's parameters (particle size and density) are altered. Concentrations produced by the model match well with the literature, producing concentrations between 0.05 and 0.25 kg/m<sup>3</sup>. Simulations of suspended sediment also show similar trends to the literature, where concentrations reach equilibrium faster in a salinity driven environment (&gt;0.5 days) when compared to a freshwater environment (∼1 day). Sensitivity results show significant differences (<em>P</em>-values &lt;0.05) between suspended sediment experiments in both freshwater and saltwater systems when all parameters (particle diameter, density, fraction of mass) vary, whereas significant differences (<em>P</em>-value &lt;0.05) between particulate tracer experiments occur primarily at the source of the release.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"270 ","pages":"Article 104525"},"PeriodicalIF":3.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562955","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}
引用次数: 0
Uranium dynamics at an iron ore mine site in Northern Sweden: Sources and mobility along the mine value chain
IF 3.5 3区 环境科学与生态学
Journal of contaminant hydrology Pub Date : 2025-03-01 DOI: 10.1016/j.jconhyd.2025.104530
Vimbainashe L. Dzimbanhete , Lena Alakangas , Torbjörn Karlsson , Elsa Peinerud , Oscar Paulsson , Olof Martinsson , Thomas Aiglsperger
{"title":"Uranium dynamics at an iron ore mine site in Northern Sweden: Sources and mobility along the mine value chain","authors":"Vimbainashe L. Dzimbanhete ,&nbsp;Lena Alakangas ,&nbsp;Torbjörn Karlsson ,&nbsp;Elsa Peinerud ,&nbsp;Oscar Paulsson ,&nbsp;Olof Martinsson ,&nbsp;Thomas Aiglsperger","doi":"10.1016/j.jconhyd.2025.104530","DOIUrl":"10.1016/j.jconhyd.2025.104530","url":null,"abstract":"<div><div>Uranium (U) release from mining has been typically associated with former U mine sites, but trace U levels in iron or base metal ores can also lead to U mobilization into ground and surface water posing potential risks due to U's chemical toxicity and radioactivity. This study investigates U sources and mobility at an iron ore mine site in Northern Sweden, where U concentrations (median 1.8 μg/l) exceeding the Swedish annual guideline value of 0.17 μg/l have been detected in a river receiving excess process water from the mine site. Drill core samples were characterized to identify the minerals hosting U in the iron ore and sequential extraction tests were conducted on solid samples from the processing plant to assess U mobility potential. Results indicate that, given its low U content, iron ore is not a significant source of the elevated U levels detected in the process water. Thorite, the main U-bearing mineral remains stable under the neutral to alkaline pH conditions in the processing plant. U speciation calculations on process water monitoring data, performed in PHREEQC with the PRODATA thermodynamic database, revealed dominant calcium uranyl carbonate complexes, specifically Ca<sub>2</sub>UO<sub>2</sub>(CO<sub>3</sub>)<sub>3</sub> and CaUO<sub>2</sub>(CO<sub>3</sub>)<sub>3</sub><sup>2−</sup>. Mine water from Leveäniemi and Gruvberget open pits, particularly Leveäniemi, was identified as the main source of U to the process water in the recirculation system. The U in mine water originates from groundwater infiltration into the open pits and leaching of U from the open pit wall rocks. Further investigation of these sources and U's geochemical behavior in mine water before it mixes with process water in the processing plant is crucial for understanding the processes driving elevated downstream U concentrations.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"270 ","pages":"Article 104530"},"PeriodicalIF":3.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Formation mechanisms of hydraulic circulation and its effects on the nitrobenzene migration in homogeneous aquifers with different medium sizes during air sparging remediation
IF 3.5 3区 环境科学与生态学
Journal of contaminant hydrology Pub Date : 2025-03-01 DOI: 10.1016/j.jconhyd.2025.104529
Xuyang Chen , Meng Yao , Liming Ren , Wei Du , Linchao Hu , Bowen Li , Mingxin Wang
{"title":"Formation mechanisms of hydraulic circulation and its effects on the nitrobenzene migration in homogeneous aquifers with different medium sizes during air sparging remediation","authors":"Xuyang Chen ,&nbsp;Meng Yao ,&nbsp;Liming Ren ,&nbsp;Wei Du ,&nbsp;Linchao Hu ,&nbsp;Bowen Li ,&nbsp;Mingxin Wang","doi":"10.1016/j.jconhyd.2025.104529","DOIUrl":"10.1016/j.jconhyd.2025.104529","url":null,"abstract":"<div><div>Porewater flow is known to introduce uncertainty in the effectiveness and extent of remediation in aquifers during air sparging (AS). In this study, the hydraulic circulation migration behavior, influencing factors, and its effects on nitrobenzene transport in AS process were investigated using light transmission visualization technology. Experimental results showed that when the air injection rate (Q) exceeded a critical threshold (Qc), porewater flow induced hydraulic circulation in homogeneous aquifers with different medium sizes. The values of Qc were found to be approximately 300 L/h for medium sand, 100 L/h for coarse sand, and 0.5 L/h for gravel aquifers. It was observed that the flow velocity of hydraulic circulation was linearly positively correlated with Q, while the zone of influence (ZOI) area was logarithmically correlated with Q. In aquifers with coarse sand, continuous channelized flow was seen to impede contaminant migration from the left to the right hydraulic circulation zone. In contrast, in gravel aquifers, discontinuous bubbly flow allowed contaminants to migrate between zones, which increased the risk of expanding the contaminant plume's range. Moreover, in aquifers with medium and coarse sand, hydraulic circulation was mainly caused by the chimney effect, whereas in gravel aquifers, oscillating bubble effects were notably observed. This observation explained why the hydraulic circulation effect in gravel aquifers was superior compared to that in medium and coarse sand aquifers. These findings are expected to contribute to expanding the remediation mechanisms, achieving precise remediation, and improving contaminant removal in AS technology.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"270 ","pages":"Article 104529"},"PeriodicalIF":3.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552655","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}
引用次数: 0
Spatio-temporal characteristics and influencing factors of water quality in Xiangxi Bay under the operation of the three gorges reservoir
IF 3.5 3区 环境科学与生态学
Journal of contaminant hydrology Pub Date : 2025-02-16 DOI: 10.1016/j.jconhyd.2025.104518
Aiping Jiang , Dongsheng Wang , Zhen Ning , Peng Li , Tao Xu , Boran Zhu , Qidong Peng , Tiantian Jin , Junqiang Lin , Di Zhang
{"title":"Spatio-temporal characteristics and influencing factors of water quality in Xiangxi Bay under the operation of the three gorges reservoir","authors":"Aiping Jiang ,&nbsp;Dongsheng Wang ,&nbsp;Zhen Ning ,&nbsp;Peng Li ,&nbsp;Tao Xu ,&nbsp;Boran Zhu ,&nbsp;Qidong Peng ,&nbsp;Tiantian Jin ,&nbsp;Junqiang Lin ,&nbsp;Di Zhang","doi":"10.1016/j.jconhyd.2025.104518","DOIUrl":"10.1016/j.jconhyd.2025.104518","url":null,"abstract":"<div><div>As the largest hydropower project in the world, the Three Gorges Reservoir (TGR) exerts significant backwater effects, leading to various water quality issues. The Xiangxi River, the largest tributary near the dam, has experienced algal bloom phenomena for several years. However, the characteristics and influencing factors of water quality during different operational periods of the reservoir remain unclear. This study analyzes 12 physical and chemical parameters of the Xiangxi Bay (XXB) from 2019 to 2023, employing a data-driven approach to explore the temporal and spatial characteristics of water quality under varying operational conditions of the TGR. It discusses the influencing factors and proposes countermeasures to address water quality challenges. The results indicate that: (1) Water quality parameters in XXB exhibit significant spatial and temporal variability, peaking in summer, with higher values observed in the middle and upper reaches. The Water Quality Index (WQI) indicates overall good water quality, while the Trophic Level Index (TLI) suggests medium eutrophication, particularly evident in spring and summer. (2) The backwater effects of the TGR have altered hydrodynamic conditions and mixing processes in XXB, significantly impacting water quality and promoting eutrophication. (3) Water quality is influenced by nutrient, organic matter, algae, and temperature, especially during low water levels in summer, with the middle and upper reaches being most affected. Key factors driving algal growth during this period include Total Nitrogen (TN), Transparency (SD), and Water Temperature (WT). (4) Effective control of eutrophication and algal blooms in XXB should focus on long-term upstream source management, close monitoring and prediction during spring and summer, and ecological operation of reservoir. This study enhances our understanding of the temporal and spatial characteristics of water quality in XXB under the operational dynamics of the TGR, providing guidance for eutrophication management and bloom prevention.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"270 ","pages":"Article 104518"},"PeriodicalIF":3.5,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437746","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}
引用次数: 0
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