Journal of contaminant hydrology最新文献

{"title":"Hydrological modeling of nutrient transport and mitigation strategies for non-point source pollution in the Bailin River basin","authors":"Hao Wang ,&nbsp;Yifeng Liu ,&nbsp;Shijiang Zhu ,&nbsp;Yang Liu ,&nbsp;Wen Xu","doi":"10.1016/j.jconhyd.2025.104617","DOIUrl":"10.1016/j.jconhyd.2025.104617","url":null,"abstract":"<div><div>The Bailin River, a key tributary of the Yangtze River, faces significant water quality challenges due to agricultural non-point source (NPS) pollution exacerbated by industrial discharge and urban runoff. This study employs the Soil and Water Assessment Tool (SWAT) to analyze the temporal and spatial dynamics of runoff as well as total nitrogen (TN) and total phosphorus (TP) loads in the Bailin River basin from 2020 to 2023. A critical source area analysis was performed to identify regions disproportionately contributing to pollutant loads. Through various simulations, including different Best Management Practices (BMPs) scenarios, the study explores their effectiveness in reducing nutrient loads. The findings reveal that nutrient losses are significantly concentrated during the flood season, with TN and TP losses accounting for 58.61 % and 58.92 % of annual totals, respectively. Specific BMP scenarios, combining optimized fertilization, vegetation buffer strips, and grass ditches, demonstrated substantial pollutant reduction, with the best combinations exceeding 58 % reductions for both TN and TP. The study emphasizes the necessity of targeted interventions in critical source areas to optimize management strategies and achieve better water quality outcomes. Continuous monitoring and adaptive management practices will be crucial to addressing ongoing challenges of non-point source pollution in this basin. Ultimately, this research contributes to a deeper understanding of NPS pollution in mountainous watersheds and highlights effective management pathways for improved ecological health and water quality.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"273 ","pages":"Article 104617"},"PeriodicalIF":3.5,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144125321","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 hydrogeochemistry evolution mechanism in high-sulfur non-ferrous metal mining areas via hydrochemical characteristics and isotopic evidence","authors":"Bing Wang ,&nbsp;Lei Ma ,&nbsp;Jia-zhong Qian ,&nbsp;Yun-hai Fang ,&nbsp;Wei Xie ,&nbsp;Dan Ding ,&nbsp;Huan Zhou ,&nbsp;Yang Long ,&nbsp;Han-ying Shen ,&nbsp;Qiang Yang","doi":"10.1016/j.jconhyd.2025.104605","DOIUrl":"10.1016/j.jconhyd.2025.104605","url":null,"abstract":"<div><div>Pollution of surrounding groundwater by mining activities and closed mines is a serious public concern around the world. To elucidate the hydrogeochemical evolution mechanism in high‑sulfur non-ferrous metal mining area, an aquifer system in Tongling of China was investigated as an example. Based on the results of hydrogeochemistry and stable isotopes，the hydrochemical evolution of aquifers is significantly influenced by water-rock interaction, while evaporation has contributed less to the hydrochemical components of groundwater. Inverse hydrogeochemical modelling demonstrated that carbonate minerals, gypsum, pyrite, halite and clay minerals as well as CO₂(g) and O₂(g) were admitted as major reactants along the flow path from the closed mine to the active mine, and mineral dissolution or precipitation and ion exchange were potential reactions. Principal component analysis confirmed that the dissolution of carbonate and sulfide predominated in hydrogeochemical evolution of groundwater. The oxidation and dissolution of sulfide are the primary factor to form acidic water, while the dissolution of limestone and dolomite will neutralize acidic water. In parallel, the leaching and ion exchange processes in the southern flow area of the mining mine are more intense, and the contribution to the chemical components of groundwater is significantly greater than that in the western flow area, which provides a reference for the zoning blocking of acid mine drainage. Although the fissure water flowing from the closed mine to the mining mine is neutral, considering the fact that the fissure water will aggravate the mine drainage and the water quality will deteriorate, active measures should be taken to identify crack channels as far as possible to reduce the risk of acid mine drainage diffusion through minimizing the hydraulic connection between them. These findings could understand the hydrogeochemical characteristics of high‑sulfur non-ferrous metal mines, thus effectively prevent groundwater pollution in the mining regions.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"273 ","pages":"Article 104605"},"PeriodicalIF":3.5,"publicationDate":"2025-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144116893","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":"Facile synthesization of NaOH activated hierarchical porous biochar from cucumber straw for the effective removal of doxycycline in aqueous solution","authors":"Guofu Huang ,&nbsp;Mianmian Wang ,&nbsp;Changchun Li ,&nbsp;Qianqian Wu ,&nbsp;Qing Liu ,&nbsp;Shasha Zhao ,&nbsp;Yucui Shi ,&nbsp;Haoran Cheng ,&nbsp;Chenxi Zhang","doi":"10.1016/j.jconhyd.2025.104612","DOIUrl":"10.1016/j.jconhyd.2025.104612","url":null,"abstract":"<div><div>The effective utilization of biomass waste for the fabrication of biochar adsorbents has aroused significant interest. In this work, a novel hierarchical porous biochar (HPBC) was successfully synthesized by dry mixing combined with one-step pyrolysis method using cucumber straw as a raw material and NaOH as an activator. The prepared HPBC was then applied to remove doxycycline (DOX) from aqueous solutions. HPBC comprised hierarchical porous structures with excellent specific surface area (1409.75 m² g⁻¹), high pore volume (0.6549 cm³ g⁻¹), and small average pore diameter (1.8582 nm). HPBC was found to contain multiple functional groups involving hydroxyl, carbonyl, amine, and aromatic structure. The adsorption kinetics and isotherm of DOX on HPBC were well described by the Avrami fractional order model and Sips model, suggesting that the adsorption process involved multiple kinetics as well as monolayer and multilayer adsorptions. HPBC exhibited an excellent adsorption capacity for DOX with the maximum value of 552.30 mg g⁻¹ at 25 °C (Sips model). The possible adsorption mechanisms of DOX on HPBC included pore filling, π-π interactions, hydrogen bonding, and electrostatic interactions. This study provided a new approach for resource utilization of straw waste and effective removal of antibiotics from water.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"273 ","pages":"Article 104612"},"PeriodicalIF":3.5,"publicationDate":"2025-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144137287","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":"Long-term water quality simulation and driving factors identification within the watershed scale using machine learning","authors":"Mingxuan Zhao ,&nbsp;Chunzi Ma ,&nbsp;Hanxiao Zhang ,&nbsp;Haisheng Li ,&nbsp;Shouliang Huo","doi":"10.1016/j.jconhyd.2025.104604","DOIUrl":"10.1016/j.jconhyd.2025.104604","url":null,"abstract":"<div><div>Understanding long-term trends and analyzing their driving factors are essential to effectively enhance water quality in watersheds. In China, although the overall quality of surface water continues to improve, significant issues remain in certain regions. The Liao River Basin, a critical industrial hub and key agricultural grain base in northeast China, continues to face unstable water quality conditions, despite over 20 years of management efforts. This study compared several data-driven models (random forest (RF), support vector machine regression (SVR), K-nearest neighbors (KNN), stacking, long short-term memory (LSTM), convolutional-long short-term memory (CNN-LSTM)), to accurately fill the water quality data gaps (i.e., total nitrogen (TN), ammonia nitrogen (NH₃-N), total phosphorus (TP), chemical oxygen demand (COD_Cr), permanganate index (COD_Mn), electroconductibility (E)) from 1980 to 2022 in Liao River Basin. In addition, the SHapley Additive exPlanations (SHAP) model was employed to quantitatively assess the driving factors of water quality. The results showed that the RF model exhibited robust predictive capabilities. TN showed a steady increase of approximately 20 % from 1980 to 2022, while the other parameters were effectively controlled. Anthropogenic activities, especially in agriculture and urban areas, were found to significantly contribute to water quality deterioration. Additionally, climatic factors such as extreme rainfall, annual average precipitation, and extreme temperatures-along with geographical factors like soil properties and slope, were found to play crucial roles in influencing water quality.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"273 ","pages":"Article 104604"},"PeriodicalIF":3.5,"publicationDate":"2025-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144089280","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":"Detailed characterization of a LNAPL-contaminated soil using X-ray microtomography and gas chromatography","authors":"Radjiv Bewi ,&nbsp;Antonio Rodríguez de Castro ,&nbsp;Olivier Atteia","doi":"10.1016/j.jconhyd.2025.104614","DOIUrl":"10.1016/j.jconhyd.2025.104614","url":null,"abstract":"<div><div>The effectiveness of remediation strategies for soils contaminated by light non-aqueous hydrocarbons (LNAPL) depends on a detailed understanding of their geological and hydrodynamic properties, as well as their spatial distribution. In this work, 3D X-ray microtomography (μ-CT) and gas chromatography (GC) are combined to characterize porosity, permeability, LNAPL saturation (<em>S</em>_<em>n</em>), and van Genuchten parameters (<em>α</em> and <em>N</em>) at a LNAPL-contaminated site. Moreover, a novel μ-CT-based method is presented to quantify LNAPL ganglia connectivity—an essential factor in understanding their spatial distribution and migration dynamics. The data obtained using this approach were employed to calculate LNAPL transmissivity. This technique, referred to as the μ-CT/GC method, was compared with LNAPL transmissivity values derived from the API-LRDM 2 hydrodynamic model (based on literature data) and from baildown test results, revealing significant discrepancies. However, the transmissivity obtained through μ-CT/GC method was more closely aligned with values measured during in-situ tests (baildown test). These findings underline the limitations of conventional transmissivity prediction approaches and pave the way for developing more effective remediation strategies. Moreover, the results highlight the significant impact of the site's strong hydrodynamic heterogeneity on pollutant retention and mobility.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"273 ","pages":"Article 104614"},"PeriodicalIF":3.5,"publicationDate":"2025-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144105615","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":"Cd migration in water-level fluctuation zones of Three Gorges reservoir: Interactions of periphytic biofilms and tryptophan","authors":"Ting Liu ,&nbsp;Mengting Xiao ,&nbsp;Rongshan Du ,&nbsp;Meng Li ,&nbsp;Xinyi Li ,&nbsp;Ying Xi ,&nbsp;Yuanfei Lv ,&nbsp;Honglin Liu ,&nbsp;Yingping Huang ,&nbsp;Tao Xu","doi":"10.1016/j.jconhyd.2025.104611","DOIUrl":"10.1016/j.jconhyd.2025.104611","url":null,"abstract":"<div><div>Periphytic biofilms (PBs) and dissolved organic matter (DOM) are key factors affecting the migration of Cd at the “water-sediment” interface. However, the specific effects of PBs and protein-like components of DOM on Cd migration within the “water-biofilm-sediment” system remain poorly understood. This study simulates the dissolution and re-immobilization of Cd at the “water-biofilm-sediment” interface in the water-level fluctuation zone (WLFZ) of the Three Gorges Reservoir (TGR), aiming to clarify the role of PBs in Cd stability. The results indicate that the concentration of dissolved Cd increased by 0.96-fold (R² = 0.992) with each doubling of L-tryptophan (L-Trp) concentration, as the functional groups of L-Trp (<img>COOH and <img>NH) formed complexes with Fe-Mn oxide-bound Cd in the sediment. In the presence of PBs and at an L-Trp concentration of 150 mg·L⁻¹, PBs utilized L-Trp, resulting in a 16.7 % reduction in dissolved organic carbon (DOC) (<em>p</em> &lt; 0.05) and an increase in protein content. Additionally, PBs contributed to a 35.12 % reduction in the peak concentration of dissolved Cd, thereby stabilizing the final Cd levels. Cd enrichment within PBs, facilitated by functional groups such as &gt;C<img>C&lt;, <img>OH, &gt;C<img>O, and <img>C<img>O<img>, led to a significant increase in Cd content (0.43 mg·kg⁻¹, <em>p</em> &lt; 0.05). These findings suggest that L-Trp degradation and Cd enrichment by PBs act synergistically to promote the re-immobilization of dissolved Cd. This study offers a novel perspective on Cd migration in WLFZs and provides insights that may be applicable to other aquatic environments where PBs are present.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"273 ","pages":"Article 104611"},"PeriodicalIF":3.5,"publicationDate":"2025-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144089281","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":"Effects of BDE-47 injection on vertical redox zonation and microbial community assemblage in capped sediment columns","authors":"Shiyu Chen ,&nbsp;Qiujin Huang ,&nbsp;Rao Qi ,&nbsp;Ge He ,&nbsp;Yafen Wang","doi":"10.1016/j.jconhyd.2025.104613","DOIUrl":"10.1016/j.jconhyd.2025.104613","url":null,"abstract":"<div><div>Polybrominated diphenyl ethers (PBDEs) are of significant interest in ecological risk assessment and bioremediation in sediments. However, their impact on microbial diversity and activity in capped lake sediments remains unclear, despite the widespread use of capping in lake management. In this study, two series of sediment columns were established to examine vertical redox zonation at 2-cm intervals from 2 to 16 cm and evaluate the impact of artificially injected PBDEs on microbial communities during a 60-day capping period. Variations in redox indicators, including nitrate, sulfate, total dissolved iron, and total dissolved manganese in porewater, showed that the capping layer (1 cm, d = 75 μm) increased the redox potential of subsurface sediments. BDE-47 was primarily concentrated in the injection layer (4–6 cm), but over time, it exhibited upward migration (0.4–0.7 cm) and a broader distribution range (0.5–1.0 cm), with no consistent decrease in the total BDE-47 mass. Microbial <em>α</em>-diversity declined, whereas microbial network analysis revealed increased connectivity and enhanced cooperation within communities in the BDE group. Notably, negative correlations between microbial taxa and iron exclusively in the BDE group, suggesting that BDE-47 counteracted capping-induced iron reduction. In contrast, sulfate showed an opposite trend with iron between the BDE and noBDE groups. <em>Methanolinea</em> [Euryarchaeota] and certain co-metabolizing dechlorinating bacteria, such as <em>Flavobacterium</em> dominated in the capping layer, were correlated to BDE-47. These findings provide the first evidence of redox-regulated natural attenuation of PBDEs in capped lake sediments, shedding light on their environmental impact and guiding sediment management strategies.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"273 ","pages":"Article 104613"},"PeriodicalIF":3.5,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099677","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":"Model-based kinetics of heavy metal enrichment in plants affected by hydrodynamics","authors":"Sha Lou ,&nbsp;Zhirui Zhang ,&nbsp;Shuguang Liu ,&nbsp;Zhongyuan Yang ,&nbsp;Shizhe Chen ,&nbsp;Yuwen Zou ,&nbsp;Irina Viktorovna Fedorova","doi":"10.1016/j.jconhyd.2025.104610","DOIUrl":"10.1016/j.jconhyd.2025.104610","url":null,"abstract":"<div><div>Heavy metal contamination threatens aquatic ecosystems by degrading water quality, biodiversity, and ecological stability. However, the role of hydrodynamics in modulating metal distribution and biogeochemical cycling, particularly in water-sediment-plant systems, remains unclear. Therefore, circular flume experiments were integrated with multiphase kinetic modeling to unravel cadmium (Cd) kinetics in water-sediment-plant systems under flow conditions. Affected by hydrodynamics, the distribution of Cd surged within 2 h and the Cd distribution coefficients showed a desorption peak within 8 h from the start of the experiment followed by reabsorption, and the hydrodynamic strength was negatively correlated with the resorption degree. Plant enrichment of heavy metals under hydrodynamics was observed initially, reaching a peak at the end of the experiment with phyto-sediment distribution coefficients of 0.22–0.25. The pseudo-second-order kinetic model effectively simulated the desorption of Cd from water, with <em>r</em>^<em>2</em> &gt; 0.97. However, the Plant Enrichment Factor (PEF) failed to accurately describe the plant enrichment kinetics of the water-sediment-plant system under hydrodynamic conditions, with the <em>r</em>^<em>2</em> of cumulative Cd uptake kinetic of plants based on PEF lower than 0.77. Consequently, the nonlinear relationship of Cd in a multi-medium distribution was identified using the Artificial Neural Network (ANN), and a modified PEF was proposed, with r² &gt; 0.96. From the modified PEF, the competitive advantage of the phytobiological action was emphasized as the experiment proceeded. The modified model proposed in this study explains the physical process of Cd enrichment by plants in the water-sediment-plant system under hydrodynamics, providing a feasible tool for the study of pollutant transport in aquatic environments, and the results can contribute to theoretical support for optimizing wetland ecosystem protection strategies.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"273 ","pages":"Article 104610"},"PeriodicalIF":3.5,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144084654","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":"Fate and transport of dissolved/colloidal metals in an aging passive treatment system for coal mine drainage: Divergent behavior of trace metals and iron","authors":"Molly M. McGuire ,&nbsp;Hannah M. Schultheis ,&nbsp;Ellen K. Herman","doi":"10.1016/j.jconhyd.2025.104609","DOIUrl":"10.1016/j.jconhyd.2025.104609","url":null,"abstract":"<div><div>Passive treatment systems are widely used to mitigate the low pH and high concentration of Fe (and often Al) that are found in abandoned mine drainage (AMD), but few studies have focused on understanding how Fe and Al removal – and the possible concurrent formation of colloids - affects the fate of trace metals in these systems. We measured trace metals at multiple locations across a 17-year-old passive treatment system in the middle western anthracite field of Pennsylvania, USA, to understand their partitioning between the dissolved and colloidal fractions and the extent to which the behavior of the major metal species controls the fate of the trace metals. The treatment system, consisting of an oxidation pond followed by three vertical flow wetlands, removes more than 90 % of the Fe, while the trace metals Co, Ni, and Zn remain at more than 70 % of their influent concentrations. Under the oxic conditions of surface water at the spillways between ponds, ferric oxyhydroxide precipitates form, which settle rapidly and do not create mobile colloids. The trace metal concentrations remain high under these conditions as the low pH (&lt; 4) inhibits adsorption to the precipitates. Standpipes discharging anoxic water from the underdrains for each upstream vertical flow wetland exhibit higher pH, leading to the precipitation of Al hydroxysulfates and the formation of colloids. The total (dissolved + colloidal) concentrations of Co and Ni correlate well with Al concentrations, suggesting adsorption or co-precipitation with the Al precipitates. Total Zn concentration is not well correlated with Al, and the colloidal fraction is significant in some, but not all standpipe samples, suggesting that Zn is forming a separate precipitate phase, likely ZnS. Overall, the ability of an aging treatment system to increase pH – not its Fe removal efficiency – is a predictor of the mobility of dissolved trace metals. However, the behavior of each metal varies substantially along different flow paths within the system.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"273 ","pages":"Article 104609"},"PeriodicalIF":3.5,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099676","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":"Application of the quality border delineation for sustainable protection of groundwater resources, qanats, against contamination using meshless numerical method","authors":"Ali Mohtashami ,&nbsp;Abdullah Al-Ghafri ,&nbsp;Majid Labbaf Khaneiki ,&nbsp;Abolfazl Akbarpour","doi":"10.1016/j.jconhyd.2025.104608","DOIUrl":"10.1016/j.jconhyd.2025.104608","url":null,"abstract":"<div><div>As sustainable groundwater resources that provide a safe and clean water supply, qanats should be protected from pollution. For this purpose, this article introduces a new concept called the “quality border” or “quality harim.” This concept acts as a boundary and determines the safe area around the qanat system in terms of contamination risk. Construction or any other activities in this area that produce pollution can enter the groundwater and get into the qanats' water, polluting it. Therefore, it is necessary to delineate this area for all qanats and prevent construction or other activities inside it. In this study, with the meshless local Petrov-Galerkin numerical method, the quality harim is determined for two qanats in the Birjand aquifer. These two qanats are selected according to the DRASTIC index map, which shows high contamination vulnerability for these qanats. Haji-Abad and Nasr-Abad are the two selected qanats with flow rates of 50 l/s and 5 l/s, respectively. The meshless local Petrov-Galerkin numerical method is then used to simulate groundwater flow in this aquifer. In the next step, to obtain the quality harim, the transport equation is solved by this numerical method in the Birjand aquifer. There are two time steps considered: 5 years (2016) and 11 years (2022). The results show that the quality harim in 2022 for the two qanats is wider than in 2016 due to groundwater drawdown and urbanization. The findings also state that both quality harims are influenced by construction, and this increases the contamination risk for both.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"273 ","pages":"Article 104608"},"PeriodicalIF":3.5,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144071112","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}