Journal of contaminant hydrology最新文献

{"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}

{"title":"Black tea waste/iron slag reactive filter media-electrokinetic for mixed heavy metals treatment from contaminated site","authors":"Faris M. Hamdi ,&nbsp;Ali Altaee ,&nbsp;Yahia Aedan ,&nbsp;John Zhou ,&nbsp;Syed Javaid Zaidi ,&nbsp;Lilyan Alsaka ,&nbsp;Raed Almalki ,&nbsp;Abdulmajeed Al-Askar ,&nbsp;Akshaya K. Samal","doi":"10.1016/j.jconhyd.2025.104517","DOIUrl":"10.1016/j.jconhyd.2025.104517","url":null,"abstract":"<div><div>Electrokinetic (EK) remediation is a cutting-edge technique used for extracting heavy metals from soils by applying an electric field. This study explores the integration of EK remediation with reactive filtration media (RFM) composed of recycled waste materials of powder iron slag/black tea waste (PIS/BTW) and granular iron slag/black tea waste (GIS/BTW) to improve the removal efficiency of single and mixed heavy metals from kaolinite and natural soils. Results demonstrated that PIS/BTW significantly outperformed GIS/BTW in heavy metal extraction, achieving 98.75 % copper removal compared to 90.06 % with GIS/BTW. Recycled RFMs achieved excellent copper removal, reaching 91.28 % for PIS/BTW and 84.90 % for GIS/BTW over 3 weeks. Specific energy consumption (SEC) increased with treatment durations, ranging from 0.055 to 0.254 kWh kg⁻¹ in kaolin soil, while 0.344 kWh kg⁻¹ increased in natural soil. For a heavy metals mixture in kaolinite soil, the removal of copper, nickel, and zinc achieved 97.15 %, 98.30 %, and 96.68 %, respectively, after 4 weeks, while in natural soil, the removal rates for copper, nickel, and zinc were 16.39 %, 89.22 %, and 84.38 % after 5 weeks. The alkaline pH of the RFMs facilitated the adsorption and precipitation of metal ions, contributing to their immobilization. The research study demonstrated the effectiveness of using recyclable and eco-friendly RFMs to optimize EK remediation, providing a sustainable and efficient solution for addressing heavy metal contamination in soils.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"270 ","pages":"Article 104517"},"PeriodicalIF":3.5,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437744","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}

{"title":"Comparative study of standard and modified groundwater vulnerability methods in the gold and iron mining regions of Western Quadrilátero Ferrífero, Brazil","authors":"Alice Zupo ,&nbsp;Rodrigo S. de Paula ,&nbsp;Jarbas L.D. Sampaio ,&nbsp;Jorge G.R. Júnior ,&nbsp;Marília C. Melo","doi":"10.1016/j.jconhyd.2025.104516","DOIUrl":"10.1016/j.jconhyd.2025.104516","url":null,"abstract":"<div><div>This study aims to evaluate the intrinsic vulnerability of the Moeda Syncline, located in the western portion of the Quadrilátero Ferrífero in the State of Minas Gerais, Brazil. This region stands out for hosting important gold and iron ore mines and is the target of geological studies due to its structural complexity and economic importance. The Moeda Syncline is responsible for feeding springs and important tributaries in the hydrographic basins of the Velhas and Paraopeba rivers, thus contributing with a great part of the water consumed by the population of the Metropolitan Region of Belo Horizonte (RMBH). The main threats to the sustainable use of water in the Moeda Syncline are urban expansion and mining enterprises. From the mapping of vulnerability to contamination it is possible to identify the areas that need to receive priority treatment. To assess the vulnerability of aquifers, four methods were selected according to the types of aquifers, namely: DRASTIC, SINTACS, GOD and EPIK. The DRASTIC method was developed to be used in any type of aquifer, the SINTACS method was developed for fissural aquifers, the GOD method for porous aquifers and the EPIK method for karst aquifers. In addition to the application of the proposed methods, modifications were made in order to adapt the method to the physical characteristics of the region, considering the less efficient parameters. From the results obtained, it was found that the most appropriate method to assess the vulnerability of the study area are those specific to each type of aquifer, considering that the proposed adaptations proved to be more efficient than the original methods. In addition, it was observed that the DRASTIC method, developed for all types of aquifers, demonstrates efficacy by indicating that the main aquifers susceptible to contamination are those of the cover layers, Cauê and Gandarela.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"270 ","pages":"Article 104516"},"PeriodicalIF":3.5,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395581","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}

{"title":"Escherichia coli transport in two acidic soils: Effect of microbially induced calcite precipitation technology","authors":"Zahra Ramezani,&nbsp;Mohammad Bagher Farhangi,&nbsp;Nasrin Ghorbanzadeh,&nbsp;Mahmoud Shabanpour","doi":"10.1016/j.jconhyd.2024.104493","DOIUrl":"10.1016/j.jconhyd.2024.104493","url":null,"abstract":"<div><div>Microbially induced calcite precipitation (MICP) while neutralizing soil pH, can lead to pore clogging which in turn may reduce bacteria transport. This study aimed to evaluate the effectiveness of the MICP process for <em>E. coli</em> filtration in two acidic soils. Two soil samples from Amlash (Am) and Lahijan (La) areas with pH values of 5.88 and 3.93, repectively, were collected and poured into plastic columns (14.92 × 2.4 cm). For the MICP reaction, the soil columns were saturated with a solidification solution (1:1 urea: CaCl₂, 1.5 M) and <em>Sporosarcina pasteurii</em> (∼10⁸ cell mL⁻¹), and incubated at 30 °C for 72 h. Leaching experiments were conducted on both MICP-treated and control soil columns at steady-state, saturated flow condition. A pulse of influent (0.1 PV) containing <em>Escherichia coli</em> (ciprofloxacin-resistant) (∼10⁸ cell mL⁻¹) and bromide tracer (1000 mg L⁻¹ KBr) was added at the top of the soil columns, followed by sterile water to collect the effluent. Recovered <em>E. coli</em>, and Br⁻, HCO₃⁻, NH₄⁺, Ca²⁺ ions were measured in the leachate. The profile of residual <em>E. coli</em> count, urease activity, and bioprecipitated CaCO₃ content were also assessed in the soil. Correlated with bioprecipitated CaCO₃, the hydraulic conductivity coefficients (<em>K</em>_s) was reduced by 4.4 and 5.8 times after MICP treatment in Am and La soils, respectively, thus bacteria leaching was significantly reduced. A higher filtration coefficient (<em>λ</em>_<em>f</em>) and recovery rate of <em>E. coli</em> were calculated in the La soil column, likely due to the lower pH and higher anion exchange capacity, which induced greater bacterial mortality and electrostatic attraction, respectively. MICP treatment reduced the average and cumulative count of <em>E. coli</em> by ∼3.4 times compared to the control column. In conclusion, the application of MICP in acidic soil increased soil pH and reduced the risk of <em>E. coli</em> transport to deeper layers by reducing soil hydraulic conductivity.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104493"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142927310","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}

{"title":"Microplastic pollution in the marine environment: Distribution factors and mitigation strategies in different oceans","authors":"Shahabaldin Rezania ,&nbsp;Saba Miri ,&nbsp;Jinwoo Cho ,&nbsp;Jin Hur ,&nbsp;Hesam Kamyab ,&nbsp;Negisa Darajeh ,&nbsp;Ali Akbar Mohammadi ,&nbsp;Farzad Molani ,&nbsp;Mohsen Taghavijeloudar","doi":"10.1016/j.jconhyd.2025.104496","DOIUrl":"10.1016/j.jconhyd.2025.104496","url":null,"abstract":"<div><div>As the COVID-19 pandemic began in 2020, plastic usage spiked, and microplastic (MP) generation has increased dramatically. It is documented that MP can transfer from the source to the ocean environment where they accumulate as the destination. Therefore, it is essential to understand their transferring pathways and effective environmental factors to determine the distribution of MPs in the marine environment. This article reviews the environmental factors that affect MP distribution in the oceans including abiotic such as ocean currents and wind direction, physical/chemical and biological reactions of MPs, natural sinking, particle size and settling velocity, and biotic including biofouling, and incorporation in fecal material. It was found that velocity and physical shearing are the most important parameters for MP accumulation in the deep ocean. Besides, this review proposes different research-based, national-level, and global-level strategies for the mitigation of MPs after the pandemic. Based on the findings, the level of MP pollution in the oceans is directly correlated to coastal areas with high populations, particularly in African and Asian countries. Future studies should focus on establishing predictive models based on the movement and distribution of MPs to mitigate the levels of pollution.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104496"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142965171","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}

{"title":"Identifying dissolved reactive phosphorus sources in agricultural runoff and leachate using phosphate oxygen isotopes","authors":"Rose C.K. Mumbi ,&nbsp;Mark R. Williams ,&nbsp;William I. Ford ,&nbsp;James J. Camberato ,&nbsp;Chad J. Penn","doi":"10.1016/j.jconhyd.2025.104501","DOIUrl":"10.1016/j.jconhyd.2025.104501","url":null,"abstract":"<div><div>Agricultural phosphorus (P) losses may result from either recently applied fertilizers or from P accumulated in soil and sediment. While both P sources pose an environmental risk to freshwater systems, differentiating between sources is crucial for identifying and implementing management practices to decrease loss. In this study, laboratory rainfall simulations were completed on runoff boxes and undisturbed soil columns before and after fertilizer application. The oxygen-18 signature of phosphate (δ¹⁸O_PO4) in fertilizer, surface runoff, subsurface leachate, and soil were analyzed (<em>n</em> = 107 samples) to quantify new (recently applied) and old (soil) P losses in runoff and leachate. Results showed that dissolved reactive P (DRP) concentration in runoff and leachate substantially increased during the rainfall simulation immediately after fertilizer application, with runoff and leachate δ¹⁸O_PO4 similar to fertilizer δ¹⁸O_PO4 signatures. Greater than 90 % of the DRP load during this event could be attributed to direct loss of P from fertilizer using δ¹⁸O_PO4. Beyond the first rainfall event after fertilizer application, DRP concentration decreased and leachate δ¹⁸O_PO4 values differed from the fertilizer values. Interpretation of isotope results was challenging because both abiotic (isotope fractionation during transport) and biotic (P cycling) processes may have influenced δ¹⁸O_PO4 signatures during these subsequent events. While abiotic effects on δ¹⁸O_PO4 appear more probable given the experimental conditions in the current study (high soil test P concentration, short duration between rainfall simulations, and strong relationship between event water and δ¹⁸O_PO4 signature), tracing or separating P sources remains highly uncertain during these events post-fertilizer application. Findings highlight both potential opportunities and challenges of using δ¹⁸O_PO4 to trace sources of P through the landscape.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104501"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143006330","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}

{"title":"Freeze-thaw effect on adsorption and transport of two sulfonamides in soil: Batch and column studies","authors":"Siyang Sun ,&nbsp;Shuyi Yu ,&nbsp;Ruihan Du ,&nbsp;Yang Wang ,&nbsp;Chunli Kang","doi":"10.1016/j.jconhyd.2025.104509","DOIUrl":"10.1016/j.jconhyd.2025.104509","url":null,"abstract":"<div><div>Freeze-thaw cycles (FTCs) have significant impacts on soil physicochemical properties, subsequently altering the fate of contaminants in soil. However, studies investigating the environmental behavior of antibiotics in soil subjected to FTCs are limited. This study investigated the effects of FTCs on the adsorption and transport of two commonly used sulfonamide antibiotics (SAs), sulfamethoxazole (SMX) and sulfapyridine (SPY), in soil. The results revealed that FTCs alter the adsorption behavior of SMX and SPY on the soil. Initially, after 1 FTC, the adsorption of both SMX and SPY decreased; however, subsequently, this adsorption gradually increased as the number of FTCs increased. This is because, during the FTCs, the increased soil pH hindered the adsorption of SAs by intensifying electrostatic repulsion between anionic SAs and soil particles. Subsequently, the increases in clay content, specific surface area (SA), small pores, and dissolved organic matter (DOM) provided more adsorption sites, overriding the initial pH effects and ultimately dominating the adsorption process. FTCs altered soil properties, which not only changed the adsorption of SAs but also induced the alteration of pore structure and the generation of preferential flow. During the vertical transport process, such changes in pore pathways played a dominant role, facilitating SMX and SPY transport in soil. The addition of heavy metals (Cd²⁺ and Cu²⁺) contributed to facilitating the transport of SMX and SPY in both unfrozen and freeze-thaw-treated soil columns. In the context of global climate change, this study offers valuable insights into the fate and environmental risks associated with pollutants in soil.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104509"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143350161","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}

{"title":"Comparison of adsorption capacity of 4-Nonylphenol on conventional and biodegradable microplastics aged under natural water","authors":"Fallon Nacaratte,&nbsp;Anahi Valdivia,&nbsp;Sylvia V. Copaja","doi":"10.1016/j.jconhyd.2024.104486","DOIUrl":"10.1016/j.jconhyd.2024.104486","url":null,"abstract":"<div><div>This study investigated the adsorption of 4-Nonylphenol (4-NP) on aged microplastics (MPs) composed of polyethylene terephthalate (PET) and poly(butylene-adipate-<em>co</em>-terephthalate)/polylactic acid (PBAT/PLA). Morphological analysis revealed wear, wrinkles, and increased surface roughness in both aged MPs, with X-ray diffraction showing slight increases in crystallinity. Infrared spectroscopy showed an increase in the carbonyl index from 2.78 to 4.37 for PBAT/PLA and 0.51 to 2.32 for PET after aging.</div><div>The natural water from the San Pedro River in Chile Atacama region (5.91 mS·cm⁻¹ conductivity, 3.25 PSU salinity, 2955 mg·L⁻¹ total dissolved solids, 435 mg·L⁻¹ CaCO₃ hardness) was used as the environmental medium and compared with a 0.01 mol·L⁻¹ CaCl₂ as a model solution.</div><div>Kinetic modeling showed a decrease in 4-NP percentage removal from 90.0 % (2277 μg∙g⁻¹ adsorption capacity) to 50.2 % (1268 μg∙g⁻¹) for PET and from 86.8 % (2087 μg∙g⁻¹) to 70.3 % (1955 μg∙g⁻¹) for PBAT/PLA when comparing the model solution to natural water, with 30 and 84 h equilibrium times, respectively. Isotherm data showed that 4-NP/PET fits BET n-layer and Temkin models, while 4-NP-PBAT/PLA fits the Toth and Hill models</div><div>The ionic composition of natural water induces cation attraction to polarized MPs surfaces, intensifying competition for adsorption sites. This involves ion and molecular cooperation, 4-NP reorientation, external diffusion effects, and surface oxidation variations, which are attributed to explaining the bilayer (PET) and monolayer (PBAT/PLA) formation.</div><div>This work contributes to understanding MP pollution and the importance of considering the bioplastics life cycle, since their waste presents significant potential to resist external factors for transporting contaminants.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104486"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142822273","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}

{"title":"Recent progresses and perspectives of polyethylene biodegradation by bacteria and fungi: A review","authors":"Yun Kong ,&nbsp;Renjuan Wang ,&nbsp;Qingyun Zhou ,&nbsp;Jiamiao Li ,&nbsp;Yimeng Fan ,&nbsp;Qi Chen","doi":"10.1016/j.jconhyd.2025.104499","DOIUrl":"10.1016/j.jconhyd.2025.104499","url":null,"abstract":"<div><div>Plastics pollution has become a serious threat to the people and environment due to the mass production, unreasonable disposal and continuous pollution. Polyethylene (PE), one of the most utilized plastics all over the world, is considered as a highly recalcitrant environmental destruction problem on account of strong hydrophobicity and high molecular weight. Therefore, it is urgently necessary to seek economical and efficient treatment and disposal methods for PE. Considering microorganisms can use various carbon sources for anabolism, they are recognized to have great potential in the biodegradation of microplastics including PE. From this point of view, the present review concentrates on providing information regarding the current status of PE biodegradation microorganisms (bacteria and fungi), and the influencing factors such as PE characteristics, cellular surface hydrophobicity, physical treatments, chemicals addition, as well as environmental conditions for biodegradation are thoroughly discussed. Furthermore, the possible biodegradation mechanisms for PE involve the biofilm formation, biodeterioration, fragmentation, assimilation, and mineralization are elucidated in detail. Finally, the future research directions and application prospects of microbial degradation are prospected in this review. It is expected to provide reference and guidance for PE biodegradation and their potential applications in real contaminated sites.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104499"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142949806","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}

{"title":"Effectiveness of double-cut-off walls on seawater intrusion and nitrate concentration in unconfined coastal aquifers","authors":"Mohamed M. Abo-Shaeshaa ,&nbsp;Ibrahim M. Rashwan ,&nbsp;Mustafa A. El-Enany ,&nbsp;Asaad M. Armanuos","doi":"10.1016/j.jconhyd.2024.104495","DOIUrl":"10.1016/j.jconhyd.2024.104495","url":null,"abstract":"<div><div>An effective coastal engineering technique for preventing seawater intrusion is constructing a cut-off wall. Nevertheless, the cut-off walls impact on nitrate concentration in downstream aquifers has not been assessed in the previous research that focused on studying a single subsurface physical barrier. In this work, a numerical model was used to examine the effect and mechanisms of the double-cut-off walls on saltwater wedge length and nitrate concentrations transported downstream of them. SEAWAT code has been implemented to simulate seawater intrusion and nitrate transport in unconfined coastal aquifers. Two cases of homogeneous aquifer (Case-H) and heterogeneous aquifer (Case-LH) were studied. The results showed significantly receded in the saltwater wedge and the spread of nitrate contamination increased due to the heterogeneous conditions. A significant effect on nitrate accumulation and an increase in the pollution area between the double-cut-off walls was observed when the second cut-off wall depth was embedded by more than 50 % of the aquifer thickness due to the weak inflow below the cut-off wall. There was no need to raise the second cut-off depth because there was a significant retraction in the saltwater interface after the first cut-off wall was embedded to a depth of more than 70 % of the aquifer thickness. Raising the second cut-off wall depth to more than 30 % of the aquifer thickness when the first cut-off wall depth ratio was less than 50 % significantly impacted the retreating of the saltwater wedge for the short distance between the double-cut-off walls. When the second cut-off wall depth ratio was less than 50 %, raising the first cut-off wall depth significantly lowered the total concentrations of the nitrate that arrived at the double-cut-off walls downstream. In addition, the total concentrations of the nitrate that traveled toward the sea were reduced to 17 % of the original nitrate concentration by raising the depth of both cut-off walls to 70 % of the aquifer thickness and the distance between them to more than 25 m. Although it was shown that the double-cut-off walls substantially reduced saltwater intrusion and nitrate concentrations, they also created a large dispersion area of nitrate pollution, especially in the heterogeneous aquifer. The retreat of the saltwater interface wedge was significantly impacted by the first cut-off wall depth in the heterogeneous aquifer. This study offers useful information for preventing saltwater intrusion and reducing nitrate concentration downstream of the double-cut-off walls, especially, the double-cut-off walls represent a new study for controlling saltwater intrusion and nitrate pollution in a coastal aquifer. The outcomes of this study can be used for the groundwater resources proper management in coastal aquifers.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104495"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143132226","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}