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Wang S, Chen J, Zhang S, Bai Y, Zhang X, Chen D, Hu J. Groundwater hydrochemical signatures, nitrate sources, and potential health risks in a typical karst catchment of North China using hydrochemistry and multiple stable isotopes. Environ Geochem Health 2024; 46:173. [PMID: 38592592 DOI: 10.1007/s10653-024-01964-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 03/20/2024] [Indexed: 04/10/2024]
Abstract
Nitrate pollution in aquatic ecosystems has received growing concern, particularly in fragile karst basins. In this study, hydrochemical compositions, multiple stable isotopes (δ2H-H2O, δ18Ο-Η2Ο, δ15Ν-ΝΟ3-, and δ18Ο-ΝΟ3-), and Bayesian stable isotope mixing model (MixSIAR) were applied to elucidate nitrate pollution sources in groundwater of the Yangzhuang Basin. The Durov diagram identified the dominant groundwater chemical face as Ca-HCO3 type. The NO3- concentration ranged from 10.89 to 90.45 mg/L (average 47.34 mg/L), showing an increasing trend from the upstream forest and grassland to the downstream agricultural dominant area. It is worth noting that 47.2% of groundwater samples exceeded the NO3- threshold value of 50 mg/L for drinking water recommended by the World Health Organization. The relationship between NO3-/Cl- and Cl- ratios suggested that most groundwater samples were located in nitrate mixed endmember from agricultural input, soil organic nitrogen, and manure & sewage. The Self-Organizing Map (SOM) and Pearson correlations analysis further indicated that the application of calcium fertilizer, sodium fertilizer, and livestock and poultry excrement in farmland elevated NO3- level in groundwater. The output results of the MixSIAR model showed that the primary sources of NO3- in groundwater were soil organic nitrogen (55.3%), followed by chemical fertilizers (28.5%), sewage & manure (12.7%), and atmospheric deposition (3.4%). Microbial nitrification was a dominant nitrogen conversion pathway elevating NO3- levels in groundwater, while the denitrification can be neglectable across the study area. The human health risk assessment (HHRA) model identified that about 88.9%, 77.8%, 72.2%, and 50.0% of groundwater samples posing nitrate's non-carcinogenic health hazards (HQ > 1) through oral intake for infants, children, females, and males, respectively. The findings of this study can offer useful biogeochemical information on nitrogen pollution in karst groundwater to support sustainable groundwater management in similar human-affected karst regions.
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Affiliation(s)
- Shou Wang
- College of Agricultural Science and Engineering, Hohai University, No. 8 Focheng West Road, Nanjing, 211100, Jiangsu, China
| | - Jing Chen
- College of Agricultural Science and Engineering, Hohai University, No. 8 Focheng West Road, Nanjing, 211100, Jiangsu, China.
| | - Shuxuan Zhang
- College of Agricultural Science and Engineering, Hohai University, No. 8 Focheng West Road, Nanjing, 211100, Jiangsu, China
| | - Yanjie Bai
- Nanjing Hydraulic Research Institute, State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering, Nanjing, 210029, China
| | - Xiaoyan Zhang
- College of Agricultural Science and Engineering, Hohai University, No. 8 Focheng West Road, Nanjing, 211100, Jiangsu, China
| | - Dan Chen
- College of Agricultural Science and Engineering, Hohai University, No. 8 Focheng West Road, Nanjing, 211100, Jiangsu, China
| | - Jiahong Hu
- Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology of CAS, Shijiazhuang, 050021, Hebei, China
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Zaryab A, Alijani F, Knoeller K, Minet E, Musavi SF, Ostadhashemi Z. Identification of groundwater nitrate sources in an urban aquifer (Alborz Province, Iran) using a multi-parameter approach. Environ Geochem Health 2024; 46:100. [PMID: 38407701 DOI: 10.1007/s10653-024-01872-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 01/12/2024] [Indexed: 02/27/2024]
Abstract
High concentrations of NO3̄ in water resources are detrimental to both human health and aquatic ecosystems. Identification of NO3̄ sources and biogeochemical processes is a crucial step in managing and controlling NO3̄ pollution. In this study, land use, hydrochemical data, dual stable isotopic ratios and Bayesian Stable Isotope Mixing Models (BSIMM) were integrated to identify NO3̄ sources and estimate their proportional contributions to the contamination of the Karaj Urban Aquifer (Iran). Elevated NO3̄ concentrations indicated a severe NO3̄ pollution, with 39 and 52% of groundwater (GW) samples displaying the concentrations of NO3̄ in exceedance of the World Health Organization (WHO) standard of 50 mg NO3̄ L-1 in the rainy and dry seasons, respectively. Dual stable isotopes inferred that urban sewage is the main NO3̄ source in the Karaj Plain. The diagram of NO3̄/Cl‾ versus Cl‾ confirmed that municipal sewage is the major source of NO3̄. Results also showed that biogeochemical nitrogen dynamics are mainly influenced by nitrification, while denitrification is minimal. The BSIMM model suggested that NO3̄ originated predominantly from urban sewage (78.2%), followed by soil organic nitrogen (12.2%), and chemical fertilizer (9.5%) in the dry season. In the wet season, the relative contributions of urban sewage, soil nitrogen and chemical fertilizer were 87.5, 6.7, and 5.5%, respectively. The sensitivity analysis for the BSIMM modeling indicates that the isotopic signatures of sewage had the major impact on the overall GW NO3̄ source apportionment. The findings provide important insights for local authorities to support effective and sustainable GW resources management in the Karaj Urban Aquifer. It also demonstrates that employing Bayesian models combined with multi-parameters can improve the accuracy of NO3̄ source identification.
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Affiliation(s)
- Abdulhalim Zaryab
- Engineering Geology and Hydrogeology, Faculty of Geology and Mines, Kabul Polytechnic University, District 5, Kabul, Afghanistan
| | - Farshad Alijani
- Department of Minerals and Groundwater Resources, Faculty of Earth Sciences, Shahid Beheshti University, Evin Ave, Tehran, Iran.
| | - Kay Knoeller
- Department Catchment Hydrology Helmholtz-Centre for Environmental Research-UFZ, 06120, Halle, Germany
| | - Eddy Minet
- Environmental Protection Agency (EPA), Dublin, Ireland
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Hermawan OR, Hosono T, Yasumoto J, Yasumoto K, Song KH, Maruyama R, Iijima M, Yasumoto-Hirose M, Takada R, Hijikawa K, Shinjo R. Mechanism of denitrification in subsurface-dammed Ryukyu limestone aquifer, southern Okinawa Island, Japan. Sci Total Environ 2024; 912:169457. [PMID: 38135078 DOI: 10.1016/j.scitotenv.2023.169457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 12/04/2023] [Accepted: 12/15/2023] [Indexed: 12/24/2023]
Abstract
Denitrification crucially regulates the attenuation of groundwater nitrate and is unlikely to occur in a fast-flowing aquifer such as the Ryukyu limestone aquifer in southern Okinawa Island, Japan. However, evidences of denitrification have been observed in several wells within this region. This study analyzed environmental isotopes (δ15NNO3 and ẟ18ONO3) to derive the rationale for denitrification at this site. Additionally, the presence of two subsurface dams in the study area may influence the processes involved in nitrate attenuation. Herein, we analyzed 150 groundwater samples collected spatially and seasonally to characterize the variations in the groundwater chemistry and stable isotopes during denitrification. The values of δ15NNO3 and δ18ONO3 displayed a progressive trend up to +59.7 ‰ and + 21 ‰, respectively, whereas the concentrations of NO3--N decreased to 0.1 mg L-1. In several wells, the enrichment factors of δ15NNO3 ranged from -6.6 to -2.1, indicating rapid denitrification, and the δ15NNO3 to δ18ONO3 ratios varied from 1.3:1 to 2:1, confirming the occurrence of denitrification. Denitrification intensively proceeds under conditions of depleted dissolved oxygen concentrations (<2 mg L-1), sluggish groundwater flow with longer residence times, high concentrations of dissolved organic carbon (>1.2 mg L-1), and low groundwater levels during the dry season with precipitation rates of <100 mm per month (Jun-Sep). SF6 analysis indicated the exclusive occurrence of denitrification in specific wells with groundwater residence times exceeding 30 years. These wells are located in close proximity to the major NE-SW fault system in the Komesu area, where the hydraulic gradient was below 0.005. Detailed geological and lithological investigations based on borehole data revealed that subsurface dams did not cause denitrification while the major NE-SW fault system uplifted the impermeable basement rock of the Shimajiri Group, creating a lithological gap at an equivalent depth that ultimately formed a sluggish groundwater area, promoting denitrification.
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Affiliation(s)
- Oktanius Richard Hermawan
- Department of Earth and Environmental Sciences, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan.
| | - Takahiro Hosono
- Faculty of Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan; International Research Organization for Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan; Research Institute for Humanity and Nature, 457-4 Motoyama, Kamigamo, Kita-ku, Kyoto 603-8047, Japan
| | - Jun Yasumoto
- Department of Regional Agriculture Engineering, University of the Ryukyus, 1-Senbaru, Nakagami District, Nishihara, Okinawa 903-0213, Japan
| | - Ko Yasumoto
- School of Marine Biosciences, Kitasato University, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa 252-0373, Japan
| | - Ke-Han Song
- Graduate School of Engineering and Science, University of the Ryukyus, 1-Senbaru, Nakagami District, Nishihara, Okinawa 903-0213, Japan
| | - Rio Maruyama
- School of Marine Biosciences, Kitasato University, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa 252-0373, Japan
| | - Mariko Iijima
- National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 7, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan
| | | | - Ryogo Takada
- Center for Strategic Research Projects, University of the Ryukyus, 1-Senbaru, Nakagami District, Nishihara, Okinawa 903-0213, Japan
| | - Kento Hijikawa
- Department of Regional Agriculture Engineering, University of the Ryukyus, 1-Senbaru, Nakagami District, Nishihara, Okinawa 903-0213, Japan; Overseas Land Improvement Cooperation Office, Rural Development Bureau, Ministry of Agriculture, Forestry, and Fisheries of Japan, 1-2-1 Kasumigaseki, Chiyoda, Tokyo 100-8950, Japan
| | - Ryuichi Shinjo
- Research Institute for Humanity and Nature, 457-4 Motoyama, Kamigamo, Kita-ku, Kyoto 603-8047, Japan; Graduate School of Engineering and Science, University of the Ryukyus, 1-Senbaru, Nakagami District, Nishihara, Okinawa 903-0213, Japan
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Fernández-Ortega J, Barberá JA, Andreo B. Real-time karst groundwater monitoring and bacterial analysis as early warning strategies for drinking water supply contamination. Sci Total Environ 2024; 912:169539. [PMID: 38141988 DOI: 10.1016/j.scitotenv.2023.169539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 11/12/2023] [Accepted: 12/18/2023] [Indexed: 12/25/2023]
Abstract
Karst aquifers have been globally exploited as a reliable source of drinking water but their intrinsic characteristics (concentrated recharge, high groundwater flow velocities, etc.) and the increase of anthropogenic pressures makes them highly vulnerable to pollution. Continuous monitoring of karst springs constitutes an effective approach for identifying episodic groundwater contamination and assuring safety conditions in drinking water supply systems. This study aims to improve groundwater protection insights through an integrated methodological approach based on real-time measurements of continuous water parameters coupled to bacterial analysis for the characterization of contamination events in a carbonate karst aquifer of a mountainous and rural area in S Spain. For this purpose, environmental, hydrodynamic and physico-chemical data in addition to bacterial activity (Escherichia coli) analysis were gathered from the analysis of eight flooding events at the two main outlets. In these karst springs, partially captured for drinking water supply, the recurrent turbid groundwater episodes suppose an important limitation for groundwater exploitation during several days, but also a concerning human health risk. The results revealed the different flow and sediment dynamics and mixing processes which determine the impact of faecal contamination derived from human activities on the karst groundwater drained by each spring. The described processes control the variable influence of allogenic recharge, which provokes notable differences regarding response times and maximum values of turbidity and associated bacterial activity in the investigated outlets. The outcomes of this work highlight the usefulness of the applied methodological framework to set the bases for an efficient implementation of early-warning strategies to prevent public health issues worldwide.
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Affiliation(s)
- Jaime Fernández-Ortega
- Department of Geology and Centre of Hydrogeology, University of Malaga (CEHIUMA), 29071 Malaga, Spain.
| | - Juan Antonio Barberá
- Department of Geology and Centre of Hydrogeology, University of Malaga (CEHIUMA), 29071 Malaga, Spain
| | - Bartolomé Andreo
- Department of Geology and Centre of Hydrogeology, University of Malaga (CEHIUMA), 29071 Malaga, Spain
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Wang F, Liu L, Xu W, Li Y, Ruan Q, Cao W. Multiple stable isotopic approaches for tracing nitrate contamination sources: Implications for nitrogen management in complex watersheds. Ecotoxicol Environ Saf 2024; 269:115822. [PMID: 38091679 DOI: 10.1016/j.ecoenv.2023.115822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 12/07/2023] [Accepted: 12/10/2023] [Indexed: 01/12/2024]
Abstract
Nitrate (NO3-) contamination of surface water is a global environmental problem that has serious consequences for watershed ecosystems and endangers human health. It is crucial to identify influences of different sources of NO3-, especially the incoming water from upper reaches. A combination of hydrochemistry and multi-isotope tracers (δ11B, δ15N-NO3-, and δ18O-NO3-) were used to determine NO3- sources and their transformation the North Jiulong River (NJLR), Southeast China. The findings revealed that NO3-, which accounted for an average of 87.1% of dissolved inorganic nitrogen (DIN), was the main chemical form of nitrogen species. The integration of dual stable isotopes of NO3-, δ11B, and hydrochemistry showed that NO3- was primarily contributed by sewage, soil nitrogen (SN), and ammonium (NH4+) via precipitation or fertilizers. The contributions from the sewage and soil nitrate source were almost equivalent and much higher than those from other sources in the NJLR watershed. The contributions from diverse sources varied seasonally and spatially. Manure and sewage (M&S) were the leading sources in the summer and autumn, accounting for 60.9 ± 8.5% and 47.3 ± 7.9%, respectively. However, NO3- fertilizers were the predominant source in the spring and winter. The NO3- inflow from upper reaches was proposed as an additional end-member to identify its contribution in the midstream and downstream in this study. The contributions of NO3- from the upper reaches were significant sources in the midstream and downstream, accounting for 27.2 ± 17.8% and 42.9 ± 21.9%, respectively. The obvious decline in local NO3-contribution shares from midstream to downstream implied structural changes in pollutant sources and regional environmental responsibility. Therefore, tracing nitrate sources and quantifying their contributions is critical for clarifying environmental responsibilities for precise local nitrogen management in watersheds.
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Affiliation(s)
- Feifei Wang
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of Environment and Ecology, Xiamen University, Xiamen, Fujian 361102, China
| | - Lihua Liu
- Fujian Xiamen Environmental Monitoring Central Station, Xiamen, Fujian 361022, China
| | - Wenfeng Xu
- Fujian Xiamen Environmental Monitoring Central Station, Xiamen, Fujian 361022, China
| | - Yasong Li
- Fujian Provincial Key Laboratory of Water Cycling and EcoGeological Processes, Xiamen 361021, China; Key Laboratory of Groundwater Contamination and Remediation of Hebei Province and China Geological Survey, Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang 050061, China
| | - Qizhen Ruan
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of Environment and Ecology, Xiamen University, Xiamen, Fujian 361102, China
| | - Wenzhi Cao
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of Environment and Ecology, Xiamen University, Xiamen, Fujian 361102, China.
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Gao H, Yang L, Song X, Guo M, Li B, Cui X. Sources and hydrogeochemical processes of groundwater under multiple water source recharge condition. Sci Total Environ 2023; 903:166660. [PMID: 37657547 DOI: 10.1016/j.scitotenv.2023.166660] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 08/26/2023] [Accepted: 08/26/2023] [Indexed: 09/03/2023]
Abstract
Ecological water replenishment (EWR) is an essential approach for improving the quantity and quality of regional water. The Chaobai River is a major river in Beijing that is replenished with water from multiple sources, including reclaimed water (RW), the South-North Water Transfer Project (SNTP), reservoir discharge (RD). The effects of multiple water source recharge (MWSR) on groundwater quality remain unclear. In this study, hydrochemical ions, isotopes (δ2H-H2O, δ18O-H2O, δ15N-NO3-, and δ18O-NO3-), mixing stable isotope analysis in R (MixSIAR), and hydrogeochemical modeling were used to quantify the contributions and impacts of different water sources on groundwater and to propose a conceptual model. The results showed that during the period before reservoir discharge, RW and SNTP accounted for 38 %-41 % and 54 % of the groundwater in their corresponding recharge areas, respectively. The groundwater in the RW recharge area contained high levels of Na+ and Cl- leading to the precipitation of halite, and was the main factor for the spatial variation in groundwater hydrochemical components. The surface water changed from Na·K - Cl·SO4 type to Ca·Mg - HCO3 type which was similar to groundwater after reservoir discharge. RD accounted for 30 % of the groundwater; however, it did not change the hydrochemical type of groundwater. Dual nitrate stable isotopes and MixSIAR demonstrated that RW was the primary source of NO3- in groundwater, contributing up to 76-89 %, and reservoir discharge effectively reduced the contribution of RW. δ15N-NO3- or δ18O-NO3- in relation to NO3-N suggests that denitrification is the main biogeochemical process of nitrogen in groundwater, whereas water recharge from the SNTP and RD reduces denitrification and dilutes NO3-. This study provides insights into the impact of anthropogenically controlled ecological water replenishment from different water sources on groundwater and guides the reasonable allocation of water resources.
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Affiliation(s)
- Heng Gao
- Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Lihu Yang
- Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Xianfang Song
- Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Minli Guo
- Beijing Water Science and Technology Institute, Beijing Engineering Technique Research Center for Exploration and Utilization of Non-Conventional Water Resources and Water Use Efficiency, Beijing 100048, China
| | - Binghua Li
- Beijing Water Science and Technology Institute, Beijing Engineering Technique Research Center for Exploration and Utilization of Non-Conventional Water Resources and Water Use Efficiency, Beijing 100048, China
| | - Xu Cui
- Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Zaryab A, Farahmand A, Mack TJ. Identification and apportionment of groundwater nitrate sources in Chakari Plain (Afghanistan). Environ Geochem Health 2023; 45:7813-7827. [PMID: 37462844 DOI: 10.1007/s10653-023-01684-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 07/06/2023] [Indexed: 10/29/2023]
Abstract
The Chakari alluvial aquifer is the primary source of water for human, animal, and irrigation applications. In this study, the geochemistry of major ions and stable isotope ratios (δ2H-H2O, δ18O-H2O, δ15N-NO3̄, and δ18O-NO3̄) of groundwater and river water samples from the Chakari Plain were analyzed to better understand characteristics of nitrate. Herein, we employed nitrate isotopic ratios and BSIMM modeling to quantify the proportional contributions of major sources of nitrate pollution in the Chakari Plain. The cross-plot diagram of δ15N-NO3̄ against δ18O-NO3̄ suggests that manure and sewage are the main source of nitrate in the plain. Nitrification is the primary biogeochemical process, whereas denitrification did not have a significant influence on biogeochemical nitrogen dynamics in the plain. The results of this study revealed that the natural attenuation of nitrate in groundwater of Chakari aquifer is negligible. The BSIMM results indicate that nitrate originated mainly from sewage and manure (S&M, 75‰), followed by soil nitrogen (SN, 13‰), and chemical fertilizers (CF, 9.5‰). Large uncertainties were shown in the UI90 values for S&M (0.6) and SN (0.47), whereas moderate uncertainty was exhibited in the UI90 value for CF (0.29). The findings provide useful insights for decision makers to verify groundwater pollution and develop a sustainable groundwater management strategy.
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Affiliation(s)
- Abdulhalim Zaryab
- Engineering Geology and Hydrogeology, Faculty of Geology and Mines, Kabul Polytechnic University, Kabul, Afghanistan.
- Highland Groundwater Research Group, Kabul, Afghanistan.
| | - Asadullah Farahmand
- Department of Hydrogeology, Ministry of Energy and Water, Kabul, Afghanistan
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Arcega-Cabrera F, León-Aguirre K, Enseñat-Soberanis F, Giácoman-Vallejos G, Rodríguez-Fuentes G, Oceguera-Vargas I, Lamas-Cosío E, Simoes N. Use of Microbiological and Chemical Data to Evaluate the Effects of Tourism on Water Quality in Karstic Cenotes in Yucatan, Mexico. Bull Environ Contam Toxicol 2023; 111:6. [PMID: 37351721 PMCID: PMC10289987 DOI: 10.1007/s00128-023-03761-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/07/2023] [Indexed: 06/24/2023]
Abstract
Cenotes are spectacular karst formations in Yucatan, Mexico, often used for recreation. However, their impact on water quality has yet to be explored in detail. Therefore, during Easter, water samples were collected from four cenotes to identify variations in water quality associated with the presence of tourists. PCO of water quality, before (PH) and during Holy Week (HW) in 2019, explained 49.02% of the total variation. The indicators contributing to the first principal coordinate's variation were Sr, K, sulfate, and chloride (0.89). Whereas, alkalinity, temperature, conductivity, nitrate, and ORP contributed to the second PC. PERMANOVA indicated a significant interaction between "cenote" and "condition" factors, and post hoc paired comparisons indicated significant differences between PH and HW conditions. Significant correlations varied among the four cenotes as the result of hydrogeological differences. Whereas, numbers of visitors were correlated with at least one fecal-matter indicator, demonstrating anthropogenic influence on the cenotes' water quality.
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Affiliation(s)
- Flor Arcega-Cabrera
- Unidad de Química en Sisal, Facultad de Química, Universidad Nacional Autónoma de México, Puerto de Abrigo Sisal, Yucatán, 97355, México.
| | - Karina León-Aguirre
- Unidad de Química en Sisal, Facultad de Química, Universidad Nacional Autónoma de México, Puerto de Abrigo Sisal, Yucatán, 97355, México
| | - Fernando Enseñat-Soberanis
- Facultad de Ciencias Antropológicas, Universidad Autónoma de Yucatán, Km 1 Carr. Mérida-Tizimin, Mérida, Yucatán, 97305, México
| | - Germán Giácoman-Vallejos
- Facultad de Ingeniería, Universidad Autónoma de Yucatán, Av. Industrias No Contaminantes por Anillo Periférico Norte, Apdo. Postal 150, Mérida, Yucatán, México
| | - Gabriela Rodríguez-Fuentes
- Unidad de Química en Sisal, Facultad de Química, Universidad Nacional Autónoma de México, Puerto de Abrigo Sisal, Yucatán, 97355, México
| | - Ismael Oceguera-Vargas
- Unidad de Química en Sisal, Facultad de Química, Universidad Nacional Autónoma de México, Puerto de Abrigo Sisal, Yucatán, 97355, México
| | - Elizabeth Lamas-Cosío
- Unidad de Química en Sisal, Facultad de Química, Universidad Nacional Autónoma de México, Puerto de Abrigo Sisal, Yucatán, 97355, México
| | - Nuno Simoes
- Facultad de Ciencias, UMDI-Sisal, Universidad Nacional Autónoma de México, Puerto de Abrigo S/N, Sisal, 97356, Mexico
- International Chair for Coastal and Marine Studies, Harte Research Institute for Gulf of Mexico Studies, Texas A and M University-Corpus Christi, Corpus Christi, TX, 78412, USA
- Laboratorio Nacional de Resiliencia Costera (LANRESC), Laboratorios Nacionales, CONACYT, Sisal, 97356, Mexico
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Cao X, He W, He W, Shi Y, An T, Wang X, Liu F, Zhao Y, Zhou P, Chen C, He J. EMMTE: An Excel VBA tool for source apportionment of nitrate based on the stable isotope mixing model. Sci Total Environ 2023; 868:161728. [PMID: 36681342 DOI: 10.1016/j.scitotenv.2023.161728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 01/06/2023] [Accepted: 01/16/2023] [Indexed: 06/17/2023]
Abstract
Dual nitrate stable isotopes combined with end-member mixing models are typically used to identify nitrate sources in fields of geochemistry and environmental science, which helps to quantitively depict the geochemical behaviors of nitrate and accurately control the sources of nitrate pollution in waters. Recently, various models with different computation principles, working efficiency, and operation difficulty have been developed and applied in the source apportionment of nitrate. In this paper, an end-member mixing model tool on Excel™, namely EMMTE, has been written with Visual Basic for Application (VBA) and built into a macro-enabled Excel™ spreadsheet. Monte Carlo simulation and constraint relative deviation between the observed and the predicted values were included in the working algorithm to solve the mass balance equation. After comparison with the internationally recognized Bayesian framework (mixing stable isotope analysis in R, MixSIAR) in different cases (three practical cases and one virtual case), the preliminary results showed that the contribution of various sources to groundwater nitrate calculated by EMMTE was highly consistent with that by MixSIAR and the performance of EMMTE seemed to be as good as that of MixSIAR as indicated by the higher goodness-of-prediction, lower root-mean-square error, and lower relative deviation. Therefore, EMMTE is applicable in the source apportionment of groundwater nitrate, and might also be extended to other water bodies and mixtures. It provides a simple, feasible, and user-friendly for front-line workers without experience with MixSIAR to quantitively source apportionment of nitrate in waters.
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Affiliation(s)
- Xu Cao
- Beijing Municipal Research Institute of Eco-Environmental Protection, Beijing 100037, China; Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Wei He
- Beijing Municipal Research Institute of Eco-Environmental Protection, Beijing 100037, China
| | - Wei He
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China.
| | - Yuanyuan Shi
- Beijing Municipal Research Institute of Eco-Environmental Protection, Beijing 100037, China
| | - Tongyan An
- Beijing Municipal Research Institute of Eco-Environmental Protection, Beijing 100037, China
| | - Xiange Wang
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Fei Liu
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Yi Zhao
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Pengpeng Zhou
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Cuibai Chen
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Jiangtao He
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
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10
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Cao X, He W, Fan M, He W, Shi Y, An T, Chen X, Zhang Z, Liu F, Zhao Y, Zhou P, Chen C, He J. Novel insights into source apportionment of dissolved organic matter in aquifer affected by anthropogenic groundwater recharge: Applicability of end-member mixing analysis based optical indices. Sci Total Environ 2023; 863:160885. [PMID: 36526179 DOI: 10.1016/j.scitotenv.2022.160885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/01/2022] [Accepted: 12/08/2022] [Indexed: 06/17/2023]
Abstract
The composition and main sources of dissolved organic matter (DOM) in groundwater may change significantly under long-term anthropogenic groundwater recharge (AGR); however, the impact of AGR on quantitative sources of groundwater DOM has seldom been reported. This study evaluated the applicability of optical indices combined with mixing stable isotope analysis in R (MixSIAR) in end-member mixing analysis (EMMA) of groundwater DOM. Fluorescent indices, including C1%, C2%, and C3%, were more sensitive to AGR than other absorbance indices, as indicated by the significant difference between the dominant area of artificial groundwater recharged by surface water and the dominant area of natural groundwater recharged by atmospheric precipitation (NGRP). BIX-C1% was selected as the optimal dual index after the screening protocol of groundwater DOM for EMMA. Our results showed that DOM in the aquifer was mainly subject to autochthonous DOM and the contribution of background groundwater to AGRSW and NGRP groundwater accounted for 36.15% ± 32.41% and 55.46% ± 37.17% (p < 0.05), respectively. Therefore, AGR significantly changed the native DOM in the groundwater. In allochthonous sources of DOM, sewage and surface water contributed 29.54% ± 24.87% and 21.32% ± 28.08%, and 24.79% ± 15.56% and 15.21% ± 14.20% to AGRSW and NGRP groundwater, respectively. The contribution of surface water to AGRSW groundwater was significantly higher than that to NGRP groundwater (p < 0.05), indicating that AGR introduced significantly more DOM from surface water to groundwater. This study provides novel insights into the quantitative source apportionment of DOM in groundwater under long-term AGR, which will facilitate the environmental risk assessment of present AGR measures and the sustainable management of clean water.
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Affiliation(s)
- Xu Cao
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Wei He
- Beijing Municipal Research Institute of Eco-Environment Protection, Beijing 100037, China
| | - Mengqing Fan
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Wei He
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China.
| | - Yuanyuan Shi
- Beijing Municipal Research Institute of Eco-Environment Protection, Beijing 100037, China
| | - Tongyan An
- Beijing Municipal Research Institute of Eco-Environment Protection, Beijing 100037, China
| | - Xiaorui Chen
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Zhanhao Zhang
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Fei Liu
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Yi Zhao
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Pengpeng Zhou
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Cuibai Chen
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Jiangtao He
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
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11
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Yue FJ, Li SL, Waldron S, Oliver DM, Chen X, Li P, Peng T, Liu CQ. Source availability and hydrological connectivity determined nitrate-discharge relationships during rainfall events in karst catchment as revealed by high-frequency nitrate sensing. Water Res 2023; 231:119616. [PMID: 36696876 DOI: 10.1016/j.watres.2023.119616] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/09/2023] [Accepted: 01/14/2023] [Indexed: 06/17/2023]
Abstract
Karst terrain seasonal monsoonal rainfall is often associated with high concentrations of nitrate-N in streams draining agricultural land. Such high concentrations can pose problems for environmental and human health. However, the relationship between rainfall events that mobilize nitrate and resulting nitrate export remains poorly understood in karst terrain. To better understand the processes that drive nitrate dynamics during rainfall events, the characteristics of individual rainfall events were analyzed using sensor technology. Thirty-eight rainfall events were separated from the high-frequency dataset spanning 19 months at a karst spring site. The results revealed that nitrate-discharge (N-Q) hysteresis in 79% of rainfall events showed anticlockwise hysteresis loop patterns, indicating nitrate export from long distances within short event periods. Karstic hydrological connectivity and source availability were considered two major determining factors of N-Q hysteresis. Gradual increase in hydrological connectivity during intensive rainfall period accelerated nitrate transportation by karst aquifer systems. Four principal components (PCs, including antecedent conditions PC1&3 and rainfall characteristics PC2&4 explained 82% of the cumulative variance contribution to the rainfall events. Multiple linear regression of four PCs explained more than 50% of the variation of nitrate loading and amplitude during rainfall events, but poorly described nitrate concentrations and hydro-chemistry parameters, which may be influenced by other factors, e.g., nitrate transformation, fertilization time and water-rock interaction. Although variation of N concentration during event flow is evident, accounting for antecedent conditions and rainfall factors can help to predict rainfall event N loading during rainfall events. Pollution of the karstic catchment occurred by a flush of nitrate input following rainfall events; antecedent and rainfall conditions are therefore important factors to consider for the water quality management. Reducing source availability during the wet season may facilitate to reduction of nitrogen loading in similar karst areas.
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Affiliation(s)
- Fu-Jun Yue
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China; School of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Si-Liang Li
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China.
| | - Susan Waldron
- School of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - David M Oliver
- Biological & Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, United Kingdom
| | - Xi Chen
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Pan Li
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Tao Peng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Cong-Qiang Liu
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
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12
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Yoshihara N, Matsumoto S, Machida I, Uchida Y. Deciphering natural and anthropogenic effects on the groundwater chemistry of Nago City, Okinawa Island, Japan. Environ Pollut 2023; 318:120917. [PMID: 36563985 DOI: 10.1016/j.envpol.2022.120917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 12/02/2022] [Accepted: 12/19/2022] [Indexed: 06/17/2023]
Abstract
A qualitative assessment of groundwater resources is significant in islands that largely depend on individual aquifers. In Okinawa Island, Japan, limestone aquifers are valuable groundwater reservoirs. However, these aquifers are sensitive to contamination due to high permeability in the conduit network. Although human activity has increased in recent decades, there remains insufficient hydrological information to assess the impact of anthropogenic loading on groundwater quality in Okinawa Island. To address this, we analyzed 4 seepage, 16 river, and 14 shallow (<10 m in depth) groundwater samples to obtain baseline chemistry and anthropogenic impact information on groundwater resources in central Nago City, northern Okinawa Island. We divided the region into three landscape units: lowland (<30 m asl), eastern, and western areas. Except for a limited number of water samples collected in the eastern mountain and coastal section of the lowland, the hydrochemistry was characterized by Ca-HCO3 type, indicating carbonate weathering within limestone-bearing lithology and Quaternary deposits. Divergent water 87Sr/86Sr values (0.707723-0.712102) with lower Sr concentrations (0.1-1.6 μmol/L) in the mountains and convergent values (0.708859-0.709184) with higher Sr concentrations (0.3-17.6 μmol/L) in the lowland suggest that the water-rock interactions in the lowland aquifer composed of Quaternary deposits are mostly responsible for the hydrochemistry of groundwater resources. The local meteoric water line (δD = 6.38 δ18O + 3.36) indicated that the water originates from precipitation, the altitude effect, and evaporation. The δ15N and δ18O in NO3- indicated the addition of manure and septic waste in the lowland aquifer. The results imply that detecting source areas of anthropogenic NO3- prior to serious groundwater pollution is important (regardless of the NO3- concentration), and isotope analyses would aid in developing appropriate action plans to mitigate or prevent future water pollution by NO3- in island regions.
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Affiliation(s)
- Naoyuki Yoshihara
- Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan.
| | - Shinji Matsumoto
- Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan
| | - Isao Machida
- Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan
| | - Youhei Uchida
- Renewable Energy Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 2-2-9 Machi-ikedai, Koriyama, 963-0298 Japan
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13
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Chen X, Zheng L, Zhu M, Jiang C, Dong X, Chen Y. Quantitative identification of nitrate and sulfate sources of a multiple land-use area impacted by mine drainage. J Environ Manage 2023; 325:116551. [PMID: 36283198 DOI: 10.1016/j.jenvman.2022.116551] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 10/13/2022] [Accepted: 10/15/2022] [Indexed: 06/16/2023]
Abstract
The rapid increase in urbanization and intensive coal mining activities have accelerated the deterioration of surface water quality. Environmental problems caused by the accumulation of nitrate and sulfate from natural, urban, and agricultural sources have attracted extensive attention. Information on nitrate and sulfate sources and their transformations is crucial for understanding the nitrogen and sulfur cycles in surface water. In this study, we monitored nitrate and sulfate in three representative rivers in mining cities in northern China. The main pollution sources and biogeochemical processes were identified by using stable isotopes (δD, δ18OH2O, δ15N, δ18ONO3, δ34S and δ18OSO4) and hydrochemistry. The contribution of natural and anthropogenic sources was quantitatively estimated based on a Bayesian mixed model. The results indicated a large variation in sulfate and nitrate sources between the different rivers. Nitrate in the Tuohe River mainly derived from manure/sewage (57.9%) and soil N (26.9%), while sulfate mainly derived from manure/sewage (41.7%) and evaporite dissolution (26.8%). For the Suihe River, nitrate was primarily sourced from chemical fertilizer (37.9%) and soil nitrogen (34.8%), while sulfate was mainly sourced from manure/sewage (33.1%) and chemical fertilizer (21.4%). For the Huihe River, nitrate mainly derived from mine drainage (56.6%) and manure/sewage (30.6%), while sulfate predominantly originated from mine drainage (58.3%) and evaporite dissolution (12.9%). Microbial nitrification was the major pathway for the migration and transformation of nitrate in the surface water. However, denitrification and bacterial sulfate reduction (BSR) did not play a significant role as aerobic conditions prevailed. In this study, we elucidated the sources and transformation mechanisms of nitrate and sulfate. Additionally, we provided a reference for formulating a comprehensive strategy for effective management and remediation of surface water contaminated with nitrate and sulfate in mining cities.
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Affiliation(s)
- Xing Chen
- School of Chemistry and Chemical Engineering, Anhui University, Hefei, 230601, Anhui, China; School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, 230601, Anhui, China.
| | - Liugen Zheng
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, 230601, Anhui, China.
| | - Manzhou Zhu
- School of Chemistry and Chemical Engineering, Anhui University, Hefei, 230601, Anhui, China
| | - Chunlu Jiang
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, 230601, Anhui, China
| | - Xianglin Dong
- Geological Survey Division, Huaibei Coal Mining Group Corporation, Huaibei, 235001, Anhui, China
| | - Yongchun Chen
- National Engineering Laboratory of Coal Mine Ecological Environment Protection, Huainan, 232001, Anhui, China
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14
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Cao X, Shi Y, He W, An T, Chen X, Zhang Z, Liu F, Zhao Y, Zhou P, Chen C, He J, He W. Impacts of anthropogenic groundwater recharge (AGR) on nitrate dynamics in a phreatic aquifer revealed by hydrochemical and isotopic technologies. Sci Total Environ 2022; 839:156187. [PMID: 35618121 DOI: 10.1016/j.scitotenv.2022.156187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/19/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
Although anthropogenic groundwater recharge (AGR) can either elevate or decline the concentration of nitrate in the phreatic aquifer with high hydraulic conductivity, the long-term impact of AGR on nitrate dynamics in the phreatic aquifer and its reason is seldom disclosed. In this study, the hydrogen and oxygen stable isotopes (δ2H-H2O and δ18O-H2O) combined with mixing stable isotope analysis in R (MixSIAR) were used to group the study area into the dominant area of AGR by surface water (AGRSW) and the dominant area of natural groundwater recharged by precipitation (NGRP). Hydrochemical parameters and multiple stable isotopes, including δ2H-H2O, δ18O-H2O, δ15N-NO3-, δ18O-NO3-, and δ13C-DIC, were applied to explore the impacts of AGR on the concentration, biogeochemical processes, and main sources of nitrate. The results showed that AGR by surface water with low nitrate content can reduce nitrate pollution in groundwater. The characteristic of δ18O-NO3- value revealed that nitrification was the primary biogeochemical process of nitrogen in groundwater. AGR may enhance nitrification as indicated by the δ18O-NO3- value closer to the nitrification theoretical line. Dual nitrate stable isotopes and MixSIAR revealed that chemical fertilizer (CF), soil nitrogen (SN), and surface water (SW) contributed 10.88%, 49.92%, and 27.64% to nitrate in AGRSW groundwater, respectively, which was significantly different from their contributions to NGRP groundwater (p < 0.05). Notably, AGR significantly increased the contribution of SW but decreased the contribution of CF and SN in groundwater. This study provided a basis and guidance for groundwater quality assessment and pollution control in the phreatic aquifer with high hydraulic conductivity.
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Affiliation(s)
- Xu Cao
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Yuanyuan Shi
- Beijing Municipal Research Institute of Eco-Environment Protection, Beijing 100037, China
| | - Wei He
- Beijing Municipal Research Institute of Eco-Environment Protection, Beijing 100037, China
| | - Tongyan An
- Beijing Municipal Research Institute of Eco-Environment Protection, Beijing 100037, China
| | - Xiaorui Chen
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Zhanhao Zhang
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Fei Liu
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Yi Zhao
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Pengpeng Zhou
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Cuibai Chen
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Jiangtao He
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
| | - Wei He
- Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China.
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15
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Wang S, Ma Y, Zhang X, Yu Y, Zhou X, Shen Z. Nitrogen transport and sources in urban stormwater with different rainfall characteristics. Sci Total Environ 2022; 837:155902. [PMID: 35568184 DOI: 10.1016/j.scitotenv.2022.155902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/17/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
Nitrogen pollution in urban stormwater has led to serious quality issues in urban water. Nitrogen pollution mitigation requires fully understanding the transport process and major nitrogen sources in urban stormwater. In this study, the concentrations and flux of various nitrogen forms during urban stormwater transport were analyzed. It was found that the concentration and flux of NO3--N and NH3-N decreased in the order of roof runoff, road runoff, and drainage runoff, while the concentration and flux of dissolved organic nitrogen (DON) and particulate nitrogen (PN) were found to be the highest in road runoff. Source quantification found that roof runoff (34%) and rainwater (34%) were the main contributors to nitrate pollution during light and moderate rains (<25 mm), while road runoff was identified as the major source (49%) of nitrate pollution during heavy rains (>25 mm) due to the large road runoff volume. Regarding particulate organic nitrogen (PON), the road runoff in commercial areas contributed most (23%) to PON pollution during light and moderate rains, while the runoff generated from pervious surfaces and drainage sediments were the primary two sources (22%) of PON during heavy rains. Moreover, the influence of rainfall characteristics on nitrate and PON source contributions was identified. The results show that antecedent dry periods were an important factor influencing nitrogen source contributions during light and moderate rains, while rainfall amount and intensity were critical factors impacting the nitrogen source contributions during heavy rains. Taking various transport processes, source contributions, and rainfall characteristics into consideration, several recommendations were given for the mitigation of nitrogen pollution in urban stormwater. This study can provide a useful perspective to understand the transport and sources of nitrogen, thus developing constructive strategies to control urban nonpoint source pollution management.
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Affiliation(s)
- Shihui Wang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, 19 Xinjiekou Outer Street, Beijing 100875, PR China
| | - Yukun Ma
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, 19 Xinjiekou Outer Street, Beijing 100875, PR China.
| | - Xiaoyue Zhang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, 19 Xinjiekou Outer Street, Beijing 100875, PR China
| | - Yu Yu
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, 19 Xinjiekou Outer Street, Beijing 100875, PR China
| | - Xuehui Zhou
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, 19 Xinjiekou Outer Street, Beijing 100875, PR China
| | - Zhenyao Shen
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, 19 Xinjiekou Outer Street, Beijing 100875, PR China
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16
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Pyrgaki K, Kelepertzis E, Argyraki A, Boeckx P, Botsou F, Dassenakis E. Identification of sources and transformations of nitrate in Cr(VI)-impacted alluvial aquifers by a hydrogeochemical and δ 15N-NO 3- and δ 18O-NO 3 - isotopes approach. Environ Sci Pollut Res Int 2022; 29:57703-57719. [PMID: 35355184 DOI: 10.1007/s11356-022-19837-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
A coupled methodology of nitrogen isotopes, hydrogeochemical characterization, multivariate statistical analysis, and SIAR Bayesian modeling has been employed to identify the sources of NO3- and N transformation processes in three alluvial aquifers (Schinos, Thiva, and Central Evia) located in central Greece where geogenic Cr(VI) co-occurs with agricultural activity and rural development. Hexavalent chromium concentrations exceed 50 μg/L in many sampling stations of the studied groundwater bodies, while nitrate contamination is evident in all three study areas with concentrations well over 50 mg/L. The mean δ15N-NO3- and δ18Ο-NO3- values are 6.67 ± 1.77‰ and 2.68 ± 1.77‰ in C. Evia, 8.72 ± 4.74‰ and 3.96 ± 4.57‰ in Schinos and 4.44 ± 1.71‰ and 2.91 ± 1.02‰ in Thiva, respectively. Domestic sewage and N-bearing fertilizers are contributing in various degrees to the observed nitrification which is the dominant transformation process of N in the studied aquifers. Multivariate statistics indicated that the main processes identified in the study areas are salinization, silicate dissolution, and groundwater contamination due to fertilizer use. It is suggested that ultramafic rock-related alluvial aquifers must be closely monitored in terms of nutrient inputs as an effective measure for controlling Cr(VI) release in groundwater.
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Affiliation(s)
- Konstantina Pyrgaki
- Department of Geology and Geoenvironment, National and Kapodistrian University of Athens, 157 84, Athens, Greece.
| | - Efstratios Kelepertzis
- Department of Geology and Geoenvironment, National and Kapodistrian University of Athens, 157 84, Athens, Greece
| | - Ariadne Argyraki
- Department of Geology and Geoenvironment, National and Kapodistrian University of Athens, 157 84, Athens, Greece
| | - Pascal Boeckx
- Isotope Bioscience Laboratory-ISOFYS, Department of Green Chemistry and Technology, Ghent University, Ghent, Belgium
| | - Fotini Botsou
- Department of Chemistry, National and Kapodistrian University of Athens, 157 84, Athens, Greece
| | - Emmanuel Dassenakis
- Department of Chemistry, National and Kapodistrian University of Athens, 157 84, Athens, Greece
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17
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Wu P, Xiao Q, Guo Y, Prelovšek M, Yu Q, Wang Q. Migration, transformation and nitrate source in the Lihu Underground River based on dual stable isotopes of δ 15N-NO 3- and δ 18O-NO 3. Environ Sci Pollut Res Int 2022; 29:48661-48674. [PMID: 35195868 DOI: 10.1007/s11356-022-19277-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 02/13/2022] [Indexed: 06/14/2023]
Abstract
Nitrate (NO3-) pollution is a common phenomenon in karst underground rivers, which are important water sources in karst landscapes. For drinking water safety and environmental protection, it is crucial to accurately identify NO3- sources and their migration and transformation processes in the Lihu Underground River. In this study, water samples of the Lihu Underground River in Guangxi were collected in May 2014, October 2014, January 2015, and July 2015, and water chemical and dual isotopic (δ15N-NO3- and δ18O-NO3-) approaches were used to evaluate the NO3- characteristics and sources in the Lihu Underground River. The concentration of NO3- in the Lihu Underground River ranged from 1.16 to 19.78 mg·L-1, with an average of 9.30 mg·L-1, which is more than 37% of the WHO standard (10 mg·L-1). The concentrations of NO3- in the wet season (May 2014 and July 2015) were slightly lower than those in the dry season (from October 2014 to January 2015) at most sampling sites due to dilution effects. The migration and transformation processes of NO3- were analyzed by comparing the measured and calculated concentrations of NO3- in the Lihu Underground River. In the dry season (from October 2014 to January 2015), the variation in NO3- concentration upstream and midstream of the Lihu Underground River was affected by exogenous input and nitrification. From midstream to the outlet of Xiaolongdong, it is affected by self-purification factors, including physical processes, chemical processes, and biological processes. In the wet season (May 2014 and July 2015), the dilution and mixing effects were the main factors controlling the variation in NO3- concentration in the Lihu Underground River. The contribution rates of potential NO3- sources (incl. atmospheric precipitation (AP), NO3- fertilizer (NF), NH4+ in fertilizer and rainfall (NFA), soil organic nitrogen (SON), and manure and sewage (M&S)) were quantitatively evaluated by using the IsoSource model. The results showed that in May 2014, the main sources of NO3- were M&S and NF, with contribution rates of 46% and 41%, respectively. In October 2014, NO3- sources were M&S with a contribution rate of 47%, followed by NFA with a contribution rate of 31%. In January 2015, NO3- sources in groundwater were M&S, with a contribution rate of 53%, followed by NFA (34%). In July 2015, the main NO3- sources were M&S and NF, whose contribution rates were 54% and 39%, respectively.
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Affiliation(s)
- Peiyan Wu
- China University of Geosciences, Beijing, 100083, China
- Key Laboratory of Karst Dynamics, MLR & Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China
| | - Qiong Xiao
- Key Laboratory of Karst Dynamics, MLR & Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China.
| | - Yongli Guo
- Key Laboratory of Karst Dynamics, MLR & Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China
| | | | - Qiong Yu
- China University of Geosciences, Beijing, 100083, China
- Key Laboratory of Karst Dynamics, MLR & Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China
| | - Qigang Wang
- Key Laboratory of Karst Dynamics, MLR & Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China
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18
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Zaryab A, Nassery HR, Knoeller K, Alijani F, Minet E. Determining nitrate pollution sources in the Kabul Plain aquifer (Afghanistan) using stable isotopes and Bayesian stable isotope mixing model. Sci Total Environ 2022; 823:153749. [PMID: 35150690 DOI: 10.1016/j.scitotenv.2022.153749] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 02/03/2022] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
The Kabul urban aquifer (Afghanistan), which is the main source of drinking water for Kabul city's inhabitants, is highly vulnerable to anthropogenic pollution. In this study, the geochemistry of major ions (including reactive nitrogen species such as NO3-, NO2-, and NH4+) and stable isotope ratios (δ15N-NO3-, δ18O-NO3-, δ18O-H2O, and δ2H-H2O) of surface and groundwater samples from the Kabul Plain were analyzed over two sampling periods (dry and wet seasons). A Bayesian stable isotope mixing model (BSIMM) was also employed to trace potential nitrate sources, transformation processes, and proportional contributions of nitrate sources in the Kabul aquifer. The plotting of δ15N-NO3- against δ18O-NO3̄ (δ15N-NO3- and δ18O-NO3- values ranged from +4.8 to +25.4‰ and from -11.7 to +18.6‰, respectively) suggests that NO3- primarily originated from the nitrification of sewage rather than artificial fertilizer. The plotting of δ15N-NO3- versus NO3-/Cl- ratios also supported the assumption that sewage is the dominant nitrate source. The results indicate that denitrification did not influence the NO3- isotopic composition in the Kabul aquifer. The BSIMM model suggests that nitrate in the dry season originated mainly from sewage (~81%), followed by soil organic N (10.5%), and chemical fertilizer (8.5%). In the wet season, sewage (~87.5%), soil organic N (6.7%), and chemical fertilizer (5.8%) were the main sources of NO3- in the Kabul aquifer. Effective land management measures should be taken to improve the sewage collection system in the Kabul Plain.
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Affiliation(s)
- Abdulhalim Zaryab
- Department of Minerals and Groundwater Resources, Faculty of Earth Sciences, Shahid Beheshti University, Evin Ave, Tehran, Iran; Engineering Geology and Hydrogeology, Faculty of Geology and Mines, Kabul Polytechnic University, District 5, Kabul, Afghanistan
| | - Hamid Reza Nassery
- Department of Minerals and Groundwater Resources, Faculty of Earth Sciences, Shahid Beheshti University, Evin Ave, Tehran, Iran.
| | - Kay Knoeller
- Department Catchment Hydrology, Helmholtz-Centre for Environmental Research - UFZ, D-06120 Halle, Germany
| | - Farshad Alijani
- Department of Minerals and Groundwater Resources, Faculty of Earth Sciences, Shahid Beheshti University, Evin Ave, Tehran, Iran
| | - Eddy Minet
- Environmental Protection Agency (EPA), Dublin, Ireland
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Wang ZJ, Yue FJ, Lu J, Wang YC, Qin CQ, Ding H, Xue LL, Li SL. New insight into the response and transport of nitrate in karst groundwater to rainfall events. Sci Total Environ 2022; 818:151727. [PMID: 34800464 DOI: 10.1016/j.scitotenv.2021.151727] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/31/2021] [Accepted: 11/12/2021] [Indexed: 06/13/2023]
Abstract
Although numerous studies focused on nitrate source, transformation and transport of river water in karst area have been reported, it's still unclear in understanding nitrate main source and transformation in karst groundwater system and how nitrate transport from soil to water during rainfall events in karst critical zone. In order to explore the response and transport of nitrate in karst groundwater to rainfall events, different depths of well water before, during and after rainfall event were sampled, and hillslope runoff, surface runoff of different land-use types during rainfall event were sampled synchronously at a typical karst agricultural catchment in Southwest China. Results showed that fluctuations of EC, pH and DO in deep borehole well (W1) and artesian well (W2) were small, on the contrary, variations of EC and DO in shallow well (W3) were large during sampling period. The nitrate concentrations and isotopic values indicated that nitrate in karst groundwater mainly originated from chemical fertilizer (CF), and influenced by denitrification process. High intensity of denitrification was observed in deep groundwater (87%) and artesian well water (almost 100%). Extremely high dual nitrate isotope values up to 46.8 ± 1.5‰ and 24.7 ± 0.5‰ were found in the deep artesian well. The small variation of water chemistry (EC, DO and pH), nitrate concentration and dual nitrate isotope values in deep wells during sampling period suggested that newly supplied nitrogen in deep groundwater during rainfall events also comes from deep groundwater. Low nitrogen concentrations in hillslope subsurface flow and surface runoff suggests that nitrogen transport process leading to increase of water nitrogen content mainly occur in depression. Nitrogen in depression soil is mainly transported to groundwater through fissures, fractures and conduits, rather than through vertical migration processes in the soil during rainfall events.
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Affiliation(s)
- Zhong-Jun Wang
- Department of Water Environment, China Institute of Water Resources and Hydropower Research, Beijing 10038, China; Technology R&D Center, Huaneng Lancang River Hydropower Inc., Kunming 650000, China
| | - Fu-Jun Yue
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China.
| | - Ji Lu
- Technology R&D Center, Huaneng Lancang River Hydropower Inc., Kunming 650000, China
| | - Yu-Chun Wang
- Department of Water Environment, China Institute of Water Resources and Hydropower Research, Beijing 10038, China
| | - Cai-Qing Qin
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Hu Ding
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Li-Li Xue
- School of Environmental Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China
| | - Si-Liang Li
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
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Chang L, Ming X, Groves C, Ham B, Wei C, Yang P. Nitrate fate and decadal shift impacted by land use change in a rural karst basin as revealed by dual nitrate isotopes. Environ Pollut 2022; 299:118822. [PMID: 35016981 DOI: 10.1016/j.envpol.2022.118822] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 01/02/2022] [Accepted: 01/06/2022] [Indexed: 06/14/2023]
Abstract
Nitrate pollution in oxygenated karst aquifers is common due to nitrification and anthropogenic inputs. However, the shift of nitrogen sources influenced by enhanced rural tourism activities and land use changes are not well understood. In this study, hydrochemistry and dual nitrate isotopes of water samples from a rural karst basin in Chongqing, southwestern China were employed to investigate the nitrate fate and its decadal change during the periods from 2007-2008 and 2017-2019. The results showed that δ15N-NO3 and δ18O-NO3 values at the groundwater basin resurgence averaged 9 ± 3.4‰ and 2.5 ± 3.4‰, respectively, with a mean NO3- concentration of 19.7 ± 5.4 mg/L in 2017-2019, clearly exceeding natural background levels. The dual isotope results suggested that nitrification occurred at the sampled sites. From 2007-2008 to 2017-2019, the mean δ15N-NO3 values from the primary sink point and the resurgence of the underground river water samples increased from -0.2 ± 2.1 to 11.2 ± 4.8‰, 4.2 ± 0.9 to 9.0 ± 3.4‰, respectively. A Bayesian mixing model in R (MixSIAR) based on the isotopes revealed that soil organic nitrogen, and manure and sewage proportions for the groundwater increased by 34% and 23%, respectively, while chemical fertilizer and atmospheric precipitation proportions decreased by 32% and 25%, respectively. These decadal changes resulted from reforestation practices and enhanced rural tourism activities in the basin, which were evidenced by the change of land use patterns. The elevated nitrogen load from the rapid development of rural tourism is likely to increase this contamination in the near future if the infrastructure cannot meet the demands. The results from this study could contribute to minimizing environmental health risks in drinking water when rural tourism activities are increasing.
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Affiliation(s)
- Longran Chang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China; National Base of International S&T Collaboration on Water Environmental Monitoring and Simulation in TGR Region, Chongqing, 400716, China
| | - Xiaoxing Ming
- State Cultivation Base of Eco-agriculture for Southwest Mountainous Land, Field Scientific Observation & Research Base of Karst Eco-environments at Nanchuan in Chongqing, Ministry of Nature Resources of the People's Republic of China, School of Geographical Sciences, Southwest University, Chongqing, 400715, China
| | - Chris Groves
- Crawford Hydrology Laboratory, Department of Geography and Geology, Western Kentucky University, Bowling Green, KY, 42101, USA; UNESCO Mammoth Cave Area Biosphere Region, Mammoth Cave, KY, 42259, USA
| | - Brian Ham
- Tennessee Department of Environment and Conservation, Division of Water Resources, Nashville, TN, 37243, USA
| | - Chaofu Wei
- College of Resources and Environment, Southwest University, Chongqing, 400715, China; National Base of International S&T Collaboration on Water Environmental Monitoring and Simulation in TGR Region, Chongqing, 400716, China
| | - Pingheng Yang
- State Cultivation Base of Eco-agriculture for Southwest Mountainous Land, Field Scientific Observation & Research Base of Karst Eco-environments at Nanchuan in Chongqing, Ministry of Nature Resources of the People's Republic of China, School of Geographical Sciences, Southwest University, Chongqing, 400715, China; Crawford Hydrology Laboratory, Department of Geography and Geology, Western Kentucky University, Bowling Green, KY, 42101, USA; Key Laboratory of Karst Ecosystem and Treatment of Rocky Desertification, Ministry of Natural Resources, IRCK by UNESCO, Guilin, 541004, China.
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21
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Zhang J, Cao M, Jin M, Huang X, Zhang Z, Kang F. Identifying the source and transformation of riverine nitrates in a karst watershed, North China: Comprehensive use of major ions, multiple isotopes and a Bayesian model. J Contam Hydrol 2022; 246:103957. [PMID: 35176529 DOI: 10.1016/j.jconhyd.2022.103957] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 11/17/2021] [Accepted: 01/05/2022] [Indexed: 06/14/2023]
Abstract
Nitrate (NO3-) contamination of surface water is a globally concern, especially in karstic regions affected by intensive agricultural activities. This study combines hydrochemistry, and environmental isotopes (δ2HH2O, δ18OH2O, δ15NNO3, and δ18ONO3) with a Bayesian isotope mixing model (Simmr) to reduce the uncertainty in estimating the contributions of different pollution sources. Samples were collected from 32 surface water sites in the Yufu River (YFR) watershed, North China, in September and December 2019. The results revealed that NO3--N was the predominant form of inorganic nitrogen that caused the deterioration of water quality in the watershed, accounting for approximately 58% of the total nitrogen (TN). The hydrochemical compositions and nitrate isotopes indicated that NO3- mainly originated from soil nitrogen (SN), ammonium fertilizer (AF), but nitrate fertilizer (NF), manure and sewage (M&S) and atmospheric precipitation (AP) were limited. The isotopic composition of nitrate in the upper reaches of the watershed was mainly affected by microbial nitrification, while the mixture of multiple sources was the dominant nitrogen transformation process in the mid-lower reaches of the watershed. Simmr model outputs revealed that SN (56.5%) and AF (29.5%) were the primary contributor to riverine NO3- pollution, followed by NF (7.1%), MS (3.6%), and AP (3.4%) sources. Moreover, an uncertainty index (UI90) of the isotope mixing showed that SN (0.73) and AF (0.67) had the highest values, followed by NF (0.22), M&S (0.22) and AP (0.10). Chemical fertilizer and SN collectively contributed >50% of nitrate during the two sampling campaigns. These results indicated that reducing the application of nitrogen fertilizers and rational irrigation are the keys to alleviate of NO3- pollution. The study is helpful in understanding the source and transformation of riverine NO3- and effectively reducing NO3- pollution in karst agricultural rivers or watersheds.
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Affiliation(s)
- Jie Zhang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430078, Hubei, PR China; School of Environmental Studies, China University of Geosciences, Wuhan 430078, Hubei, PR China
| | - Mingda Cao
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430078, Hubei, PR China; School of Environmental Studies, China University of Geosciences, Wuhan 430078, Hubei, PR China
| | - Menggui Jin
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430078, Hubei, PR China; School of Environmental Studies, China University of Geosciences, Wuhan 430078, Hubei, PR China.
| | - Xin Huang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430078, Hubei, PR China; School of Environmental Studies, China University of Geosciences, Wuhan 430078, Hubei, PR China
| | - Zhixin Zhang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430078, Hubei, PR China; School of Environmental Studies, China University of Geosciences, Wuhan 430078, Hubei, PR China
| | - Fengxin Kang
- Shandong Provincial Bureau of Geology and Mineral Resources, Jinan 250013, Shandong, PR China; Shandong Provincial Research Center of Groundwater Environment Protection and Remediation, Jinan 250014, Shandong, PR China
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22
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Ren K, Pan X, Yuan D, Zeng J, Liang J, Peng C. Nitrate sources and nitrogen dynamics in a karst aquifer with mixed nitrogen inputs (Southwest China): Revealed by multiple stable isotopic and hydro-chemical proxies. Water Res 2022; 210:118000. [PMID: 34996012 DOI: 10.1016/j.watres.2021.118000] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 11/22/2021] [Accepted: 12/20/2021] [Indexed: 06/14/2023]
Abstract
The nitrate (NO3-) contamination of karst aquifers as an important drinking water reservoir is increasing globally. Understanding the behavior of nitrogen (N) in karst aquifers is imperative for effective groundwater quality management. This study combined multiple stable isotopes (δ2H-H2O, δ18O-H2O, δ13C-DIC, δ15N-NO3, and δ18O-NO3), including hydro-chemical data, with a tracer test and a Bayesian isotope mixing (SIAR) model to elucidate the NO3- sources and N cycling within the Babu karst aquifer in Guizhou Province, Southwest China. Nitrate isotopes and SIAR model revealed that manure and sewage, nitrogen fertilizer, and soil organic nitrogen were the three dominant NO3- sources in winter, contributing to 37%, 32%, and 31% to spring NO3-, and 38%, 31%, and 31% to surface water NO3-, respectively. The δ18O-NO3 values of sampled waters ranging from 0.3‰ to 13.7‰ (mean of 7.7 ± 3.0‰; N = 63) and the significant negative correlations between δ15N-NO3 and δ13C-DIC in the spring waters (P < 0.01) revealed that nitrification was the primary N transformation process in the Babu watershed. Whereas, denitrification might still occur locally, confirmed by the enriched values of δ15N-NO3 (14.3 ± 7.6‰; N = 6) and high denitrification extent (46.6 ± 22.2%; N = 6) in the springs from residential areas, and by elevated δ13C-DIC (-11.2 ± 0.6‰; N = 26) and δ15N-NO3 values (18.9 ± 5.2‰; N = 26) in the boreholes. During the base flow period, point-inputs of the AMD-impacted stream and sewage waters, and short transit time (<5 days) were conducive to nitrification processes in the karst conduit, resulting in elevated NO3- concentration and NO3-/Cl- ratio at the watershed outlet. Approximately 50% of NO3- flux at the outlet was derived from nitrification, indicating that a significant extent of nitrification occurred in the NH4+-contaminated karst conduit, which may be a new NO3- source to receiving rivers and lakes. This study provided an integrated method for exploring the N dynamics in contaminated karst aquifers. Moreover, the study highlighted that the point N sources control required particular attention for groundwater protection and restoration.
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Affiliation(s)
- Kun Ren
- Key Laboratory of Karst Dynamics, Ministry of Natural Resources &Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, No. 50, Qixing Road, Guangxi, Guilin 541004, China; School of Geography and Planning, Sun Yat-Sen University, Guangzhou 510275, China.
| | - Xiaodong Pan
- Key Laboratory of Karst Dynamics, Ministry of Natural Resources &Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, No. 50, Qixing Road, Guangxi, Guilin 541004, China.
| | - Daoxian Yuan
- Key Laboratory of Karst Dynamics, Ministry of Natural Resources &Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, No. 50, Qixing Road, Guangxi, Guilin 541004, China
| | - Jie Zeng
- Key Laboratory of Karst Dynamics, Ministry of Natural Resources &Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, No. 50, Qixing Road, Guangxi, Guilin 541004, China
| | - Jiapeng Liang
- Key Laboratory of Karst Dynamics, Ministry of Natural Resources &Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, No. 50, Qixing Road, Guangxi, Guilin 541004, China
| | - Cong Peng
- Key Laboratory of Karst Dynamics, Ministry of Natural Resources &Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, No. 50, Qixing Road, Guangxi, Guilin 541004, China
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Cao X, Yang S, Wu P, Liu S, Liao J. Coupling stable isotopes to evaluate sources and transformations of nitrate in groundwater and inflowing rivers around the Caohai karst wetland, Southwest China. Environ Sci Pollut Res Int 2021; 28:45826-45839. [PMID: 33880699 DOI: 10.1007/s11356-021-13827-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 04/05/2021] [Indexed: 06/12/2023]
Abstract
Nitrate is one of the most common pollutants in aquatic ecosystems, particularly in highly vulnerable karst aquifers. In Caohai Lake, an important karst wetland in southwestern China, karst surface water and groundwater are important recharge water sources, and nitrates flow into the wetland along with the surface water and groundwater, degrading the wetland water quality. Therefore, identifying the sources of nitrate in the surface water and groundwater in the Caohai catchment is of great significance to the protection of the wetland water environment. In this study, the nitrate concentrations, hydrochemistry and multiple stable isotope ratios (δ18O-H2O, δD-H2O, δ15N-NO3- and δ18O-NO3-) were used to identify the sources and fate of the NO3- in the groundwater and inflowing rivers around the Caohai wetland. The results showed that the NO3- concentrations in the groundwater samples from the southern side exceeded the WHO limit during the wet season, while other samples did not exceed the limit. The mean concentrations of NO3- in groundwater were higher than those in the inflowing river water, and NO3- concentrations decreased in the order of wet season>dry season>normal season in the groundwater and inflowing rivers. The hydrochemistry and multiple isotope ratios suggest that the nitrate transformation was dominated by nitrification processes, while denitrification had an influence on the transformation of NO3- (as evidenced by isotopes) in groundwater during the dry season. According to the analyses based on a stable isotope analysis in R (SIAR), sewage and manure were the main sources of NO3- in the groundwater, while sewage, manure and chemical fertilizer were the major sources of NO3- in the inflowing river water; therefore, the scientific use of farmland fertilizers and the treatment of domestic sewage should be strengthened to safeguard groundwater quality and control the NO3- concentrations in rivers.
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Affiliation(s)
- Xingxing Cao
- College of Resource and Environmental Engineering, Guizhou University, Guiyang, 550025, Guizhou, China.
- Key Laboratory of Karst Georesources and Environmental, Ministry of Education, Guizhou University, Guiyang, 550025, China.
| | - Shidi Yang
- College of Resource and Environmental Engineering, Guizhou University, Guiyang, 550025, Guizhou, China
- Key Laboratory of Karst Georesources and Environmental, Ministry of Education, Guizhou University, Guiyang, 550025, China
| | - Pan Wu
- College of Resource and Environmental Engineering, Guizhou University, Guiyang, 550025, Guizhou, China
- Key Laboratory of Karst Georesources and Environmental, Ministry of Education, Guizhou University, Guiyang, 550025, China
| | - Shan Liu
- College of Resource and Environmental Engineering, Guizhou University, Guiyang, 550025, Guizhou, China
- Key Laboratory of Karst Georesources and Environmental, Ministry of Education, Guizhou University, Guiyang, 550025, China
| | - Jiahao Liao
- College of Resource and Environmental Engineering, Guizhou University, Guiyang, 550025, Guizhou, China
- Key Laboratory of Karst Georesources and Environmental, Ministry of Education, Guizhou University, Guiyang, 550025, China
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