Journal of contaminant hydrology最新文献

{"title":"Effects of tire wear particles on the water retention of soils with different textures in the full moisture range","authors":"Amir Verdi ,&nbsp;Mahyar Naseri","doi":"10.1016/j.jconhyd.2024.104345","DOIUrl":"https://doi.org/10.1016/j.jconhyd.2024.104345","url":null,"abstract":"<div><p>Tire wear particles (TWPs) are significant contributors to microplastic pollution in the environment, yet there is limited scientific information concerning their impact on soil hydraulic properties. This study aimed to investigate the impact of TWPs at different concentrations (1, 4, 8, and 16% of the air-dried mass of packed soil samples, w/w) on the water retention curves (WRC) of southern California soils with five different textures (clay, clay loam, silt loam, sandy loam, and loamy sand). The concentrations of 8% and 16% were selected to represent extreme pollution scenarios that might occur near highway corridors. High-resolution water retention data, spanning from saturation to oven dryness, were generated using HYPROP™ and WP4C dew point meter instruments. We also developed WRC scaling equations based on the quantity of TWPs. The bulk density of the samples decreased as the TWP concentration in soils increased. The inclusion of very high concentrations of TWPs (8% and 16% w/w) led to a significant reduction in soil moisture content in the intermediate and dry ranges across various soil textures. However, at the same moisture range, adding 1% TWPs had a minimal impact on soil moisture reduction, while the influence of the 4% TWPs concentration treatment was noticeable only in loamy sand and partially in clay loam soils. Additionally, the overall plant available water decreased with increasing TWP concentrations, except for the clay soil. The texture-specific scaling models exhibited promising performance, with RMSE values ranging from 0.0061 to 0.0120 cm³ cm⁻³. When bulk density was included as an additional input predictor to construct a single scaling model for all textures, the RMSE increased. Nevertheless, it still indicated a good fit ranging from 0.007 to 0.024 cm³ cm⁻³, highlighting the suitability of simple scaling for identifying WRC in TWPs-polluted soils, particularly for practical purposes. The findings of this study can contribute to a better understanding and quantification of the impact of TWPs on soil hydrology.</p></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0169772224000494/pdfft?md5=4a3b9d1541243a3cde86f77cdd32e482&pid=1-s2.0-S0169772224000494-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140633339","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":"Evaluate the groundwater quality and human health risks for sustainable drinking and irrigation purposes in mountainous region of Chongqing, Southwest China","authors":"Rui Li ,&nbsp;Yuting Yan ,&nbsp;Jiaqian Xu ,&nbsp;Chang Yang ,&nbsp;Si Chen ,&nbsp;Yangshuang Wang ,&nbsp;Yunhui Zhang","doi":"10.1016/j.jconhyd.2024.104344","DOIUrl":"https://doi.org/10.1016/j.jconhyd.2024.104344","url":null,"abstract":"<div><p>Groundwater is crucial for agriculture and domestic consumption. This research investigated the hydrogeochemical properties and contaminant sources of groundwater within the mountainous terrain of northern Chongqing, with the objective of evaluating its appropriateness for irrigation and potable use. The hydrochemical type of the groundwater was HCO₃ − Ca, dominated by silicate and calcite dissolutions. High NO₃⁻ (29.03% exceeds 10 mg/L) were attributed to the overuse of agricultural fertilizers. A comprehensive evaluation was conducted to determine the groundwater suitability for agricultural and potable uses. The results showed that groundwater in the southwestern region, particularly within the Yangtze River mainstem watershed, exhibited less suitability for irrigation owing to its lower mineralization, in contrast to the northeastern region near the Daning River watershed. But this trend is reversed for drinking purposes. Overall, the groundwater was appropriate for both drinking (93.55% were classified as excellent) and irrigation (70.98% were classified as low restriction) purposes in the study area. Deterministic and probabilistic noncarcinogenic health risk analyses centered on nitrate exposure revealed that infants (with 13.79% of samples &gt;1) were at greater risk than children (8.58%), adult males (6.98%), and adult females (5.24%). This underscores the urgency to reduce nitrogen fertilizer usage and improve water management in the region. This research will provide guidance for the sustainable groundwater management in mountainous regions.</p></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140622101","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":"An integrated evaluation of bioenhanced in situ LNAPL dissolution","authors":"Eric A. Seagren ,&nbsp;David J. Hollander ,&nbsp;David A. Stahl ,&nbsp;Bruce E. Rittmann","doi":"10.1016/j.jconhyd.2024.104338","DOIUrl":"10.1016/j.jconhyd.2024.104338","url":null,"abstract":"<div><p>Performance evaluation of in situ bioremediation processes in the field is difficult due to uncertainty created by matrix and contaminant heterogeneity, inaccessibility to direct observation, expense of sampling, and limitations of some measurements. The goal of this research was to develop a strategy for evaluating in situ bioremediation of light nonaqueous-phase liquid (LNAPL) contamination and demonstrating the occurrence of bioenhanced LNAPL dissolution by: (1) integrating a suite of analyses into a rational evaluation strategy; and (2) demonstrating the strategy's application in intermediate-scale flow-cell (ISFC) experiments simulating an aquifer contaminated with a pool of LNAPL (naphthalene dissolved in dodecane). Two ISFCs were operated to evaluate how the monitored parameters changed between a “no bioremediation” scenario and an “intrinsic <em>in situ</em> bioremediation” scenario. Key was incorporating different measures of microbial activity and contaminant degradation relevant to bioremediation: contaminant loss; consumption of electron acceptors; and changes in total alkalinity, pH, dissolved total inorganic carbon, carbon-stable isotopes, microorganisms, and intermediate metabolites. These measurements were integrated via mass-flux modeling and mass-balance analyses to document that in situ biodegradation of naphthalene was strongly accelerated in the “intrinsic in situ bioremediation” scenario versus “no bioremediation.” Furthermore, the integrated strategy provided consistent evidence of bioenhancement of LNAPL dissolution through intrinsic bioremediation by a factor of approximately 2 due to the biodegradation of the naphthalene near the pool/water interface.</p></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140765116","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":"Radon deficit technique applied to the study of the ageing of a spilled LNAPL in a shallow aquifer","authors":"Alessandra Briganti ,&nbsp;Mario Voltaggio ,&nbsp;Claudio Carusi ,&nbsp;Elisa Rainaldi","doi":"10.1016/j.jconhyd.2024.104342","DOIUrl":"https://doi.org/10.1016/j.jconhyd.2024.104342","url":null,"abstract":"<div><p>A recent diesel spill (dated January 2019 ± 1 month) in a refilling station is investigated by the Radon deficit technique. The primary focus was on quantifying the LNAPL pore saturation as a function of duration of ageing, and on proposing a predictive model for on-site natural attenuation. A biennial monitoring of the local fluctuating shallow aquifer has involved the saturated zone nine times, and the vadose zone only once. Rn background generally measured in external and upstream wells is elaborated further due to the site characteristics, using drilling logs and phreatic oscillations. Notably, this study marks the first application of the Rn deficit method to produce a detailed Rn background mapping throughout the soil depth. Simultaneously, tests are performed on LNAPL surnatant samples to study diesel ageing. In particular, they are focused on temporal variations of LNAPL viscosity (from an initial 3.90 cP to 8.99 cP, measured at 25 °C, after 34 months), and Rn partition coefficient between the pollutant and water (from 47.7 to 80.2, measured at 25 °C, after 14 months). Rn diffusion is also measured in different fluids (0.092 cm² s⁻¹, 1.14 × 10⁻⁵ cm² s⁻¹, and 2.53 × 10⁻⁶ cm² s⁻¹ at 25 °C for air, water and LNAPL, respectively) directly. All parameters and equations utilized during this study are introduced, discussing their influence on Radon deficit technique from a theoretical point of view. Experimental findings are used to mitigate the effect of LNAPL ageing and of phreatic oscillations on determination of LNAPL saturation index (S.I._LNAPL). Finally, S.I._LNAPL dataset is discussed and elaborated to show the pollutant attenuation across subsurface over time, induced by natural processes primarily. The proposed predictive model for on-site natural attenuation suggests a half-removal time of one year and six months. The significance of such models lies in their capability to assess site-specific reactions to pollutants, thereby enhancing the effectiveness of remediation efforts over time. These experimental findings may offer a novel approach to application of Rn deficit technique and to environmental remediation of persistent organic compounds.</p></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140622046","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":"Presence of microplastics in the groundwater of volcanic islands, El Hierro and La Palma (Canary Islands)","authors":"Joselin S. Rodríguez-Alcántara ,&nbsp;Albert Contreras-Llin ,&nbsp;Noelia Cruz-Pérez ,&nbsp;Alejandro García-Gil ,&nbsp;Carlos Baquedano ,&nbsp;Miguel Ángel Marazuela ,&nbsp;M. Silvia Diaz-Cruz ,&nbsp;Jorge Martínez León ,&nbsp;Juan C. Santamarta","doi":"10.1016/j.jconhyd.2024.104340","DOIUrl":"https://doi.org/10.1016/j.jconhyd.2024.104340","url":null,"abstract":"<div><p>The increasing amount of plastic litter worldwide is a serious problem for the environment and its biodiversity, ecosystems, animal and human welfare and the economy. The degradation of these plastics leads to microplastics (MPs), which have been reported for the first time in groundwater in the Canary archipelago. This research investigates the presence of MPs at nine different points on La Palma and El Hierro, where samples were collected in galleries, wells and springs during the month of December 2022. Six different polymers were found with Fourier transform infrared spectroscopy (FTIR) – polypropylene (PP), polyethylene (PE), cellulose (CEL), polyethylene terephthalate (PET), polystyrene (PS) and polymethyl methacrylate (PMMA). The particle concentrations found ranged from 1 to 23 n/L, with a maximum particle size of 1900 μm, the smallest being 35 μm. PP and PE were the most common polymers found in the analysis, associated with the use of packaging, disposable products, textiles and water pipes, related to poorly maintained sewerage networks where leaks occur, allowing these MPs to escape into the environment and end up in groundwater. The detection of microplastic pollution in groundwater emphasises environmental hazards, including biodiversity disruption and water source contamination. Additionally, it presents potential risks to human health by transferring contaminants into the food chain and through respiratory exposure.</p></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0169772224000445/pdfft?md5=86716e0cd873805aa1285b5656763fad&pid=1-s2.0-S0169772224000445-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140543660","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":"Modeling subsurface contaminant transport from a former open-pit uranium mine in fractured granites (La Ribière, France): Reducing uncertainties with geophysics","authors":"S. Guillon ,&nbsp;J.-F. Girard ,&nbsp;E. Williard ,&nbsp;D. Virlogeux ,&nbsp;M. Descostes","doi":"10.1016/j.jconhyd.2024.104343","DOIUrl":"https://doi.org/10.1016/j.jconhyd.2024.104343","url":null,"abstract":"<div><p>The long-term management of tailings from former uranium (U) mines requires an in-depth understanding of the hydrogeological processes and water flow paths. In France, most of the legacy U mines are located in fractured crystalline (plutonic) rocks, where the intrinsic subsurface heterogeneity adds to the uncertainties about the former extraction and milling activities and the state of the mine when production was ceased. U ores were mainly processed by sulfuric acid leaching, leading to high-sulfate-content mill tailings now contained in several tailing storage facilities (TSFs). The La Ribière site, located in western central France, is a former open-pit and underground U mine, closed in 1992 and used to store mill tailings. This site is being used as a test case to establish a workflow in order to explain and predict water flow and subsurface contaminant transport. A conceptual model of water flow and sulfate transport, at the scale of the La Ribière watershed, is first developed based on available information and hydrogeochemical monitoring. Recent geophysical investigations allows refining this model. Electrical Resistivity Tomography (ERT) proves to be efficient at localizing the extent of the highly conductive sulfate plume inherited from the U-mill tailings, but also at imaging the weathering profile. Magnetic Resonance Sounding (MRS), despite the limited signal intensity due to the low porosity in crystalline rocks, gives some insight into the porosity values, the depth of the fractured layer and the location of the low-porosity ore-processing muds. Based on this conceptual model, a 3D flow and non-reactive transport model with the METIS code is developed and calibrated. This model allows predicting the evolution of the sulfate plume, but will also be used in future investigations, to build reactive transport models with simplified hydrogeology for U and other reactive contaminants.</p></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140555205","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":"Microplastics, their abundance, and distribution in water and sediments in North Chennai, India: An assessment of pollution risk and human health impacts","authors":"Vignesh K.S. ,&nbsp;V.N. Prapanchan ,&nbsp;V.N. Indhiya Selvan ,&nbsp;Natchimuthu Karmegam ,&nbsp;Woong Kim ,&nbsp;Damia Barcelo ,&nbsp;Muthusamy Govarthanan","doi":"10.1016/j.jconhyd.2024.104339","DOIUrl":"https://doi.org/10.1016/j.jconhyd.2024.104339","url":null,"abstract":"<div><p>Plastic particles, measuring &lt;5 mm in size, mainly originate from larger plastic debris undergoing degradation, fragmenting into even smaller fragments. The goal was to analyze the spatial diversity and polymer composition of microplastics (MPs) in North Chennai, South India, aiming to evaluate their prevalence and features like composition, dimensions, color, and shape. In 60 sediment samples, a combined count of 1589 particles were detected, averaging 26 particles per 5 g⁻¹ of dry sediment. The water samples from the North Chennai vicinity encompassed a sum of 1588 particles across 71 samples, with an average of 22 items/L. The majority of MPs ranged in size from 1 mm to 500 μm. The ATR-FTIR results identified the predominant types of MPs as polystyrene, polyvinyl chloride, polyethylene, polyethylene terephthalate, and polypropylene in sediment and water. The spatial variation analysis revealed high MPs concentration in landfill sites, areas with dense populations, and popular tourist destinations. The pollution load index in water demonstrated that MPs had contaminated all stations. Upon evaluating the polymeric and pollution risks, it was evident that they ranged from 5.13 to 430.15 and 2.83 to 15,963.2, which is relatively low to exceedingly high levels. As the quantity of MPs and hazardous polymers increased, the level of pollution and corresponding risks also escalated significantly. The existence of MPs in lake water, as opposed to open well water, could potentially pose a cancer risk for both children and adults who consume it. Detecting MPs in water samples highlights the significance of implementing precautionary actions to alleviate the potential health hazards they create.</p></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140338822","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":"A data-driven approach for simplifying the estimation of time for contaminant plumes to reach their maximum extent","authors":"A. Köhler ,&nbsp;P.K. Yadav ,&nbsp;R. Liedl ,&nbsp;J.B. Shil ,&nbsp;T. Grischek ,&nbsp;P. Dietrich","doi":"10.1016/j.jconhyd.2024.104336","DOIUrl":"https://doi.org/10.1016/j.jconhyd.2024.104336","url":null,"abstract":"<div><p>Globally there exist a very large number of contaminated or possibly contaminated sites where a basic preliminary assessment has not been completed. This is largely, among others, due to limited simple methods/models available for estimating key site quantities such as the maximum plume length, further denoted as <span><math><msub><mi>L</mi><mi>max</mi></msub></math></span> and the corresponding time <span><math><mi>T</mi><mo>=</mo><msub><mi>T</mi><mi>Lmax</mi></msub></math></span>, at which the plume reaches its maximum extent <span><math><mi>L</mi><mo>=</mo><msub><mi>L</mi><mi>max</mi></msub></math></span>. An approach to easily obtain an estimate of <span><math><msub><mi>T</mi><mi>Lmax</mi></msub></math></span> in particular is presented in this work. Limited availability of high-quality field data, particularly of <span><math><msub><mi>T</mi><mi>Lmax</mi></msub></math></span>, necessitates the use of synthetic data, which constrains the overall model development works. Taking BIOSCREEN-AT (transient 3D model) as a base model, this work proposes second-order polynomial models, with only two parameters, for estimating <span><math><msub><mi>L</mi><mi>max</mi></msub></math></span> and <span><math><msub><mi>T</mi><mi>Lmax</mi></msub></math></span>. This reformulation of the well established solution significantly reduces data requirement and workload for initial site assessment purposes. A global sensitivity analysis (<span>Morris, 1991</span>), using a large number of random synthetic data, identifies the first-order decay rate constants in the plume <span><math><mfenced><msub><mi>λ</mi><mi>EFF</mi></msub></mfenced></math></span> and at the source <span><math><mfenced><mi>γ</mi></mfenced></math></span> as dominantly most influential for <span><math><msub><mi>T</mi><mi>Lmax</mi></msub></math></span>. For <span><math><msub><mi>L</mi><mi>max</mi></msub></math></span>, the first-order decay rate constant <span><math><msub><mi>λ</mi><mi>EFF</mi></msub></math></span> and groundwater velocity <span><math><mi>v</mi></math></span> are the two important parameters. The sensitivity analysis also identifies that these parameters non-linearly impact <span><math><msub><mi>T</mi><mi>Lmax</mi></msub></math></span> or <span><math><msub><mi>L</mi><mi>max</mi></msub></math></span>. With this information, the proposed polynomial models (each for <span><math><msub><mi>L</mi><mi>max</mi></msub></math></span> and <span><math><msub><mi>T</mi><mi>Lmax</mi></msub></math></span>) were trained to obtain model coefficients, using a large amount of synthetic data. For verification, the developed models were tested using four datasets comprising over 100 sample sets against the results obtained from BIOSCREEN-AT and the developed BIOSCREEN-AT-based steady-state model. Additionally, the developed models were evaluated against two well documented field sites. The proposed models largely simplify estimation, particularly, of <span><math><msub><mi>T</mi><mi>Lmax</mi></msub","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0169772224000408/pdfft?md5=7bd414760c25c81509e797f3aeb99ea3&pid=1-s2.0-S0169772224000408-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140308762","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":"Statistical and machine learning analysis for the application of microbially induced carbonate precipitation as a physical barrier to control seawater intrusion","authors":"Charalampos Konstantinou ,&nbsp;Yuze Wang","doi":"10.1016/j.jconhyd.2024.104337","DOIUrl":"https://doi.org/10.1016/j.jconhyd.2024.104337","url":null,"abstract":"<div><p>Seawater intrusion in coastal aquifers is a significant problem that can be addressed through the construction of subsurface dams or physical cut-off barriers. An alternative method is the use of microbially induced carbonate precipitation (MICP) to reduce the hydraulic conductivity of the porous medium and create a physical barrier. However, the effectiveness of this method depends on various factors, and the scientific literature presents conflicting results, making it challenging to generalise the findings. To overcome this challenge, a statistical and machine learning (ML) approach is employed to infer the causes for the reduction in hydraulic conductivity and identify the optimum MICP parameters for preventing seawater intrusion. The study involves data curation, exploratory analysis, and the development of various models to fit the input data (k-Nearest Neighbours – kNN, Support Vector Regression – SVR, Random Forests – RF, Gradient Boosting – XgBoost, Linear model with interaction terms, Ensemble learning algorithms with weighted averages – EnL-WA and stacking – EnL-Stack). The models performed reasonably well in the region where permeability reduction is sensitive to carbonate increase capturing the permeability reduction profile with respect to cementation level while demonstrating that they can be used in initial assessments of the specific conditions (e.g., soil properties). The best performing algorithms were the EnL-Stack and RF followed by XgBoost and SVR. The MICP method is effective in reducing hydraulic conductivity provided that the various biochemical parameters are optimised. Critical biochemical parameters for successful MICP formulations are the bacterial optical density, the urease activity, calcium chloride concentration and flow rate as well as the interaction terms across the properties of the porous media and the biochemical parameters. The models were used to identify the optimum MICP formulation for various porous media properties and the maximum permeability reduction profiles across cementation levels have been derived.</p></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140191493","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":"Characteristics of bacterial community structure in the sediment of Chishui River (China) and the response to environmental factors","authors":"Fei Di ,&nbsp;Donghui Han ,&nbsp;Guang Wang ,&nbsp;Wenbo Zhao ,&nbsp;Daokun Zhou ,&nbsp;Nan Rong ,&nbsp;Shou Yang","doi":"10.1016/j.jconhyd.2024.104335","DOIUrl":"https://doi.org/10.1016/j.jconhyd.2024.104335","url":null,"abstract":"<div><p>Sediment microorganisms performed an essential function in the biogeochemical cycle of aquatic ecosystems, and their structural composition was closely related to environmental carrying capacity and water quality. In this study, the Chishui River (Renhuai section) was selected as the research area, and the concentrations of environmental factors in the water and sediment were detected. High⁃throughput sequencing was adopted to reveal the characteristics of bacterial community structures in the sediment. In addition, the response of bacteria to environmental factors was explored statistically. Meanwhile, the functional characteristics of bacterial were also analyzed based on the KEGG database. The results showed that the concentration of environmental factors in the water and sediment displayed spatial differences, with the overall trend of midstream &gt; downstream &gt; upstream, which was related to the wastewater discharge from the Moutai town in the midstream directly. Proteobacteria was the most dominant phylum in the sediment, with the relative abundance ranged from 52.06% to 70.53%. The distribution of genus-level bacteria with different metabolic activities varied in the sediment. Upstream was dominated by <em>Massilia</em>, <em>Acinetobacter</em>, and <em>Thermomonas.</em> In the midstream, <em>Acinetobacter</em>, <em>Cloacibacterium</em> and <em>Comamonas</em> were the main genus. Nevertheless, the abundance of <em>Lysobacter, Arenimonas</em> and <em>Thermomonas</em> was higher in the downstream. Redundancy analysis (RDA) showed that total nitrogen (TN) and total phosphorus (TP) were the main environmental factors which affected the structure of bacterial communities in sediment, while total organic carbon (TOC) was the secondary. The bacterial community was primarily associated with six biological pathway categories such as metabolism. Carbohydrate metabolism and amino acid metabolism were the most active functions in the 31 subfunctions. This study could contribute to the understanding of the structural composition and driving forces of bacteria in the sediment, which might benefit for the ecological protection of Chishui River.</p></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140187382","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}