Journal of contaminant hydrology最新文献

{"title":"Distribution of potentially toxic elements in sediments of the municipal river channel (Balu), Dhaka, Bangladesh: Ecological and health risks assessment","authors":"Md Muzammel Hossain ,&nbsp;Iffat Jahan ,&nbsp;Abdullah Al Nahian ,&nbsp;Karen H. Johannesson ,&nbsp;Stephen J. Maxwell ,&nbsp;Daochen Zhu","doi":"10.1016/j.jconhyd.2024.104492","DOIUrl":"10.1016/j.jconhyd.2024.104492","url":null,"abstract":"<div><div>The concern of potential toxic elements (PTEs) contamination in the river ecosystem is growing due to anthropological activity. The contents of seven PTEs in sediments from the Balu River channel were analyzed using atomic absorption spectroscopy (AAS) and an environmental risk model. Several PTEs were found in the sediment at high levels, including zinc (Zn), copper (Cu), arsenic (As), lead (Pb), cadmium (Cd), nickel (Ni), and mercury (Hg), that might pose a risk to human and ecological health. The highest mean concentration of PTEs in sediment followed in decreasing order Zn (1365.21 mg/kg) &gt; Cu (149.34 mg/kg) &gt; Pb (46.34 mg/kg) &gt; Ni (34.78 mg/kg) &gt; As (6.31 mg/kg) &gt; Cd (2.34 mg/kg) &gt; Hg (1.03 mg/kg). In addition, most of these PTEs were significantly correlated (<em>p</em> &lt; 0.05) among the sites and exceeded the safety guideline value. The geo-accumulation index (<em>Igeo</em>), contamination factor (CF), and pollution load index (PLI) showed high levels of PTEs contamination and moderately polluted to highly polluted levels of these elements. At the BL3, BL4, and BL6 sites within the study site, the ecological risk (PERI) score was extremely high, and the PERI values range found was from 75.39 to 355.72. Every PTE had a slightly greater concentration during the dry season than the wet season. Interestingly, PTE accumulation from sediment indicated non-carcinogenic risk (<span><math><msub><mi>HQ</mi><mi>dermal</mi></msub></math></span>) in human health, whereas most of the sites showed carcinogenic risk (<span><math><msub><mi>CR</mi><mi>dermal</mi></msub></math></span>) to human health (adult and child) due to Cd and Ni accumulation. Multivariate statistical analysis (MVSA) indicated the most likely anthropological sources were the untreated wastes discharged in the river sampling area. People who come into contact with polluted sediments are constantly exposed to Ni and Cd pollution, which increases the risk of cancer and non-cancerous diseases. So, continuous PTE monitoring is advised by this study to assess ecological and human health risks.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104492"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143132227","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":"Induced polarization monitoring of in-situ chemical oxidation for quantification of contaminant consumption","authors":"Teng Xia ,&nbsp;Johan Alexander Huisman ,&nbsp;Chen Chao ,&nbsp;Jing Li ,&nbsp;Deqiang Mao","doi":"10.1016/j.jconhyd.2024.104481","DOIUrl":"10.1016/j.jconhyd.2024.104481","url":null,"abstract":"<div><div>Dynamic monitoring of in-situ chemical oxidation (ISCO) of LNAPLs in groundwater is the foundation for evaluating remediation effectiveness. In this study, spectral (SIP) and time-domain induced polarization (TDIP) measurements are conducted in laboratory columns and sandboxes to monitor the ISCO of LNAPL for characterizing oxidant transport and quantifying contaminant consumption under different injection strategies. To support the interpretation, this was combined with total petroleum hydrocarbon (TPH), hydrochemistry and computed tomography (CT) measurements. Experiments were performed using two media, and the monitoring results showed similar variations in key parameters. The electrical resistivity, chargeability and TPH decreased significantly during ISCO remediation, while the hydrochemical parameters showed an increasing trend. Specifically, IP variations before and after injection revealed that more oxidant remained in the source area using a multiple-injection strategy compared to a single-injection strategy. The effect of contaminant consumption under well-controlled conditions on electrical resistivity was &lt;3 % and the effect on chargeability was &lt;8 %. In conditions with oxidant migration, the effect of oxidant on the resistivity and chargeability was similar at ∼89 % in the source area, whereas the oxidant had a greater effect on the resistivity (&gt;58 %) than the chargeability (&lt;40 %) outside the source area. Based on the experimental results, a conceptual model for the IP response during ISCO remediation is proposed and we delineate the pore structural characteristics of porous media based on the conceptual model. Oxidant injection develops a high conductivity environment and causes a decrease in LNAPLs content and number of interfaces, leading to the suppression of the IP response. In conclusion, IP measurement in combination with supporting information clearly enables the characterization of the ISCO remediation of LNAPLs in groundwater and facilitates the pore structure characterization of porous media based on the IP conceptual model.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104481"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142794723","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 karst conduit structure on breakthrough curves: Experiments and modeling","authors":"Tingqiao Yang,&nbsp;Guanping An,&nbsp;Xinhao Hu,&nbsp;Jinna Chen,&nbsp;Tao Huang","doi":"10.1016/j.jconhyd.2025.104504","DOIUrl":"10.1016/j.jconhyd.2025.104504","url":null,"abstract":"<div><div>Due to the complexity of karst conduit systems, field tracer tests can produce a variety of breakthrough curves (BTCs) and present challenges in analyzing BTCs and determining solute transport pathways. In this study, tracer experiments were conducted in the laboratory using karst pipe structures such as asymmetric branch pipe and pool models to investigate the effect of karst conduit structure on BTC. Subsequently, experimental BTCs were simulated using the OM-MADE (One Dimensional Model of Multiple Adsorption, Diffusion, and Storage in Exchange Zones) model, and the results were compared with the experimental results. The results show that the main pipe in the branch pipe model significantly affects the number of BTC peaks, with increasing two-branch pipe spacing (D_L) leading to a decrease in peak concentration and delaying peak time. In the pool model, increasing the pool volume or number leads to lower peak concentrations and stronger tailing effects. In the continuous pool model, the outlet location has the most significant influence on the BTC morphology. The OM-MADE model accurately simulates the bimodal and trailing features of the BTCs (R² ≥ 0.9), demonstrating its reliability in predicting groundwater contamination. This study provides key insights that can help predict and manage groundwater contamination.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104504"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143238888","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":"The nexus of microplastics, food and antimicrobial resistance in the context of aquatic environment: Interdisciplinary linkages of pathways","authors":"Shiwangi Dogra ,&nbsp;Manish Kumar ,&nbsp;Jian Zang","doi":"10.1016/j.jconhyd.2025.104512","DOIUrl":"10.1016/j.jconhyd.2025.104512","url":null,"abstract":"<div><div>The exponential rise in plastic production since the mid-20th century has led to the widespread existence of microplastics in various ecosystems, posing significant environmental and health concerns. Microplastics, defined as plastic particles smaller than 5 mm, have infiltrated diverse environments, including oceans, freshwater bodies, and even remote Arctic ice. Their ability to absorb toxic chemicals and serve as vectors for microbial colonization raises concerns about their impacts on aquatic organisms and human health. This review examines the pathways by which microplastics infiltrate the food chain, highlighting their presence in various food items consumed by humans. Furthermore, it explores the nexus between microplastics and antimicrobial resistance (AMR), elucidating how microorganisms inhabiting plastic surfaces facilitate the transmission of antibiotic resistance genes (ARGs). The review underscores the urgent need for interdisciplinary research integrating environmental science, microbiology, public health, and policy to address the multifaceted challenges posed by microplastics. Standardized protocols for sampling and analysis are essential to enable meaningful comparisons across research and regions. By collectively addressing these challenges, we can strive towards a more sustainable and resilient future for ecosystems and human societies.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104512"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143239630","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":"Concentration-discharge relations and transient metal loads reveal spatiotemporal variability in solute-generation mechanisms in a mine-affected watershed","authors":"Connor P. Newman ,&nbsp;Alexis Navarre-Sitchler ,&nbsp;Robert L. Runkel ,&nbsp;Rory Cowie","doi":"10.1016/j.jconhyd.2025.104513","DOIUrl":"10.1016/j.jconhyd.2025.104513","url":null,"abstract":"<div><div>Concentration-discharge (CQ) relations are commonly used to understand geochemical and hydrologic controls on the generation of solutes in watersheds. Despite the widespread application of CQ relations, this technique has been infrequently applied to acid mine drainage (AMD) sites, but the CQ framework may allow mechanistic understanding of remedial outcomes such as impoundment of water within underground mines. Results of CQ analyses and changes in metal loads in an AMD affected watershed in Colorado, USA indicate that dissolved loads increased at many individual locations following water impoundment within mine workings. Although increased loads were observed at most individual locations, these increases were offset by a large decrease in loading from the largest mine. A loading analysis that included data from an instream monitoring location showed a statistically significant decrease in Fe and Zn after bulkhead emplacement, indicating a net positive effect of bulkheads. Streams generally displayed dilution CQ patterns whereas mines and springs showed either flushing or chemostatic patterns prior to bulkheading, which transitioned to chemostatic patterns following bulkheading, indicating a transition from dynamic to equilibrium geochemical processes. Saturation indices for sulfide and secondary minerals indicated that mines and springs were near equilibrium for phases including schwertmannite, fluorite, and gypsum. Saturation indices vary through time for mines suggesting progressive leaching of sulfide minerals as the mass of available minerals in the mine workings decreases. Together, these diverse analyses provide an integrated understanding of the variability in solute generating processes in this watershed and may inform remediation plans for similarly affected sites by indicating the nature of mineralogic controls on water quality.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104513"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143350750","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":"Release of poly- and perfluoroalkyl substances from AFFF-impacted soils: Effects of water saturation in vadose zone soils","authors":"Stefanie M. Shea ,&nbsp;Charles E. Schaefer ,&nbsp;Tissa Illangasekare ,&nbsp;Christopher P. Higgins","doi":"10.1016/j.jconhyd.2025.104506","DOIUrl":"10.1016/j.jconhyd.2025.104506","url":null,"abstract":"<div><div>Soil samples collected from an aqueous film-forming foam (AFFF)-impacted sandy soil formation at two depth intervals above the water table were used in bench-scale column experiments to evaluate the release of poly- and perfluoroalkyl substances (PFASs) under different degrees of water saturation. Artificial rainwater was applied to the soils under constant and variably saturated conditions. Results from constant saturation experiments suggest that retention of PFAS mass at air-water interfaces was evident in the deep soil (f_oc &lt; 0.00068 g/g), particularly for longer chain and zwitterionic compounds, while PFAS mass release from the shallow soil (f_oc = 0.0034 g/g) was consistent with kinetically controlled desorption from the soil. The release profiles for the perfluoroalkyl sulfonamides (FASAs) differed from other PFASs examined, with more FASAs generally being eluted under fully saturated conditions from both the shallow and deep soils. Importantly, variably saturated conditions resulted in more PFAS eluting from the soils: the average release rate of PFHxS from both soils was 10-fold higher under variably saturated conditions than under constant conditions. Both soils retained significant fractions of the total PFAS mass even after extensive flushing (51–83.8 % for PFOS). These results suggest that PFAS transport in vadose zone soils is influenced by air-water interfaces, but solid-phase desorption also plays a role. Overall, these results are consistent with observations in the field and serve to confirm key mechanisms that control PFAS leaching.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104506"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143038964","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":"Cellulose –Polyvinylalcohol supported magnetic nanocomposites from lentil husk for sequestration of cationic dyes from the aqueous solution: Kinetics, isotherm and reusability studies","authors":"Afsana Khatoon ,&nbsp;Shaziya Siddiqui ,&nbsp;Nazrul Haq","doi":"10.1016/j.jconhyd.2025.104503","DOIUrl":"10.1016/j.jconhyd.2025.104503","url":null,"abstract":"<div><div>The study emphasize on the synthesis of eco-friendly cellulose based magnetic nanocomposite derived from <em>Lens cullnaris</em> husk and Poly Vinyl Alcohol (Fe₃O₄@LENT/PVA) for the adsorption of Crystal Violet, Methylene Blue and Malachite Green Dye. The structural and functional morphology was determined by SEM-EDAX analysis and FTIR. The crystalline of Fe₃O₄@LENT/PVA was analyzed by XRD and pore size was determined by BET. The surface area of nanocellulose Fe₃O₄@LENT/PVA was found to be 22.308 m²/g and the pore volume of 0.074cm³/g. The Fe₃O₄@LENT/PVA nanocomposites show successful adsorption of CV, MB and MG in 120 min equilibrium time at pH 7 for CV and 8 for MB and MG respectively. The Fe₃O₄@LENT/PVA nanocomposites was best fitted Langmuir isotherm and follows pseudo 2nd order kinetics with intra particle as rate controlling mechanism. The nanocellulose Fe₃O₄@LENT/PVA composite shows good monolayer adsorption capacity in the order of CV(357 mg/g) &gt; MB(112.35 mg/g) &gt; MG(111.11 mg/g). Thermodynamic study reveals the process is endothermic and spontaneous in nature with ΔG⁰ value less than 20KJ mol⁻¹ at respective temperatures indicating Physiosorption. The nano-cellulose Fe₃O₄@LENT/PVA composite can be effectively desorb dyes by 0.1 M NaOH. The nanocellulose Fe₃O₄@LENT/PVA composite proves to be an effective adsorbent showing regeneration ability upto five times for all the dyes.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104503"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143074354","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 as adsorbent for Pb2+ and Cd2+: A comparative study of polypropylene, polyvinyl chloride, high-density polyethylene, and low-density polyethylene","authors":"Tae-Jung Ha ,&nbsp;Woo-Ri Lim ,&nbsp;Junyong Heo ,&nbsp;Minhee Lee ,&nbsp;Minjune Yang","doi":"10.1016/j.jconhyd.2024.104491","DOIUrl":"10.1016/j.jconhyd.2024.104491","url":null,"abstract":"<div><div>Microplastics (MPs) in aquatic environments adsorb heavy metals, thereby posing potential environmental risks. However, further research is needed to elucidate the adsorption behavior of different types of MPs for various heavy metals. The aim of this study was to characterize four types of MPs: polypropylene (PP), polyvinyl chloride (PVC), high-density polyethylene (HDPE), and low-density polyethylene (LDPE). Moreover, their Pb²⁺ and Cd²⁺ adsorption properties were determined to investigate the differences in their capacity to function as heavy metal adsorbents. MPs were characterized via scanning electron microscopy (SEM) using energy dispersive X-ray spectrometer (EDS), Brunauer–Emmett–Teller (BET) analysis, and Fourier transform infrared spectroscopy (FTIR). Adsorption experiment data were analyzed using the Langmuir and Freundlich isotherm models to evaluate the adsorption capacity of the MPs. Based on the results of the adsorption isotherm models and 2D-COS FTIR, the presence of oxygen-containing functional groups, including hydroxyl, carbonyl, and carboxyl groups influences the adsorption process of Pb²⁺ and Cd²⁺ onto PP and PVC, with the maximum adsorption capacities (<em>Q</em>_<em>m</em>) being 0.759 mg/g and 0.495 mg/g, respectively. Combination of the adsorption isotherm data and characteristics of MPs revealed that the following order of adsorption efficiencies of MPs for each heavy metal: PP &gt; LDPE &gt; PVC &gt; HDPE for Pb²⁺ and PP &gt; PVC &gt; LDPE &gt; HDPE for Cd²⁺. The results of this study suggest that MPs, particularly PP and PVC, may serve as vectors for heavy metal transport in aquatic environments, highlighting the need for further research to assess their environmental impact.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104491"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142909637","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":"Assessing data variability in groundwater quality monitoring of contaminated sites through factor analysis and multiple linear regression models","authors":"Davide Sartirana ,&nbsp;Chiara Zanotti ,&nbsp;Alice Palazzi ,&nbsp;Ilaria Pietrini ,&nbsp;Paola Frattini ,&nbsp;Andrea Franzetti ,&nbsp;Tullia Bonomi ,&nbsp;Marco Rotiroti","doi":"10.1016/j.jconhyd.2024.104471","DOIUrl":"10.1016/j.jconhyd.2024.104471","url":null,"abstract":"<div><div>Monitoring of long-term contaminant concentrations trends is essential to verify that attenuation processes are effectively occurring at a site. However, monitoring data are often affected by extreme variability which prevents the identification of clear concentration trends. The variability is higher in long-screened monitoring wells, which are currently used at many contaminated sites, although it has been known since the 1980s that monitoring data from long-screened wells can be biased. Understanding the factors that may influence the variability of monitoring data is pivotal. To this end, following hydrochemical conceptual modelling using a multi-method approach, the variability of hydrocarbon concentrations from fully screened monitoring wells was assessed over eleven years at a former oil refinery located in Northern Italy. The proposed methodology combined factor analysis with multiple linear regression models.</div><div>Results pointed out a higher variability in hydrocarbon concentrations at the plume fringe and a lower variability at the plume source and core. 44–46 % of the total variability in measured hydrocarbon concentrations is due to “intrinsic plume heterogeneity”, related to the three-dimensional structure of a contaminant plume, which becomes thinner at the edge, creating a vertical heterogeneity of redox conditions at the plume fringe. This variability, expressed as increasing concentrations of sulfate and decreasing concentrations of methane, represents a background variability that cannot be reduced by improving sampling procedures. The remaining 56–54 % of the total variability may be due to the non-standardization of some purging and sampling operations, such as pump intake position, purging and sampling time/flow rates and variations in the analytical methods. This finding suggests that monitoring improvements in fully screened wells by standardizing all purging/sampling operations or using sampling techniques that can reduce the actual screen length (e.g., packers or separation/dual pumping techniques) would reduce data variability by more than half.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104471"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142780260","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":"Dynamic transformation and leaching processes of nitrogen in a karst agricultural soil under simulated rainfall conditions","authors":"Ping Zhang ,&nbsp;Fu-Jun Yue ,&nbsp;Xiao-Dan Wang ,&nbsp;Sai-Nan Chen","doi":"10.1016/j.jconhyd.2024.104494","DOIUrl":"10.1016/j.jconhyd.2024.104494","url":null,"abstract":"<div><div>Frequent exchange of surface water and groundwater in karst agricultural areas results in soil nutrient loss during rainfall and consequent deterioration of the aquatic environment. To understand nitrogen (N) transformation and leaching processes from karst soil during rainfall events, two typical N fertilizers were added to karst soil and consequently investigated the nitrogenous species using soil column experiments system. The contents of various N forms in the soil and leachate were analyzed, and the net nitrification and the N leaching rates were calculated. The results revealed that NH₄⁺ and NO₂⁻ accumulation and variation occurred primarily in shallow soils, indicating that shallow soils were the primary sites for ammonification and nitrification processes. The net nitrification rate in the soil was higher with application of urea (12.5 mg N kg⁻¹d⁻¹) than with manure (2.4 mg N kg⁻¹d⁻¹). Peak N content indicated that it took only 7 days for N to migrate from the topsoil to 90 cm depth of soil after applying urea during successive intense rainfall events. NO₃⁻ leaching was predominantly composed of N, followed by DON, with leaching ratios of 31.1 % for the urea column and only 1.7 % for the manure column. These results highlight that the rapid nitrification of urea application coupled with intensive rainfall accelerated nitrate leaching into subterraneous streams in karst hydrological system, supporting a significant contribution from agricultural fertilizer loss during rainfall in karst area.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"269 ","pages":"Article 104494"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142927309","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}