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Wang D, Li P, Mu D, Liu W, Chen Y, Fida M. Unveiling the biogeochemical mechanism of nitrate in the vadose zone-groundwater system: Insights from integrated microbiology, isotope techniques, and hydrogeochemistry. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167481. [PMID: 37788773 DOI: 10.1016/j.scitotenv.2023.167481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 09/09/2023] [Accepted: 09/28/2023] [Indexed: 10/05/2023]
Abstract
Clarifying the biogeochemical mechanism of nitrate (NO3-) in the vadose zone-groundwater system, particularly in agricultural contexts, is crucial for mitigating groundwater NO3- pollution. However, comprehensive studies on the impacts of changes in chemical indicators and microbial communities on NO3- are still lacking. This paper aims to address this gap by employing hydrogeochemistry, stable isotopes, and microbial techniques to assess the NO3- biogeochemical processes in the vadose zone-groundwater system. The findings suggested that NO3- in upper soil layers was primarily influenced by plant root absorption, assimilation, and nitrification processes. The oxygen contents gradually decreased with the nitrification process, resulting in the occurrence of the denitrification. However, denitrification predominantly occurred in the 60-80 cm soil layer in the study area. The limited thickness of the denitrification layer results in less NO3- consumption, leading to increased NO3- leaching into groundwater. Hydrochemical and isotopic characteristics further indicated that groundwater NO3- concentrations were mainly controlled by nitrification, followed by denitrification and mixing processes. The 16S rRNA sequencing analysis revealed great influences of soil sampling depths and groundwater NO3- concentrations on the microbial community structure. Additionally, the PICRUSt2-based prediction results demonstrated a stronger potential for dissimilatory reduction of NO3- to ammonium (DNRA) in both soil and groundwater compared to the other processes, potentially due to the widespread presence of the nrfH functional genes. However, the chemical indicators and isotopes used in this study did not support the occurrence of DNRA process in the vadose zone-groundwater system. This finding highlights the importance of an integrated approach combining microbiological, isotopic, and hydrogeochemical data to comprehensive understanding biogeochemical processes. The study developed a conceptual model elucidating the NO3- biogeochemical processes in the vadose zone-groundwater system within an agricultural area, contributing to enhanced comprehension and advancement of sustainable management practices for groundwater nitrogen.
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Affiliation(s)
- Dan Wang
- School of Water and Environment, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China; Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of the Ministry of Education, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China; Key Laboratory of Eco-hydrology and Water Security in Arid and Semi-arid Regions of the Ministry of Water Resources, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China
| | - Peiyue Li
- School of Water and Environment, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China; Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of the Ministry of Education, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China; Key Laboratory of Eco-hydrology and Water Security in Arid and Semi-arid Regions of the Ministry of Water Resources, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China.
| | - Dawei Mu
- School of Water and Environment, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China; Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of the Ministry of Education, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China; Key Laboratory of Eco-hydrology and Water Security in Arid and Semi-arid Regions of the Ministry of Water Resources, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China
| | - Weichao Liu
- School of Water and Environment, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China; Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of the Ministry of Education, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China; Key Laboratory of Eco-hydrology and Water Security in Arid and Semi-arid Regions of the Ministry of Water Resources, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China
| | - Yinfu Chen
- School of Water and Environment, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China; Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of the Ministry of Education, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China; Key Laboratory of Eco-hydrology and Water Security in Arid and Semi-arid Regions of the Ministry of Water Resources, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China
| | - Misbah Fida
- School of Water and Environment, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China; Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of the Ministry of Education, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China; Key Laboratory of Eco-hydrology and Water Security in Arid and Semi-arid Regions of the Ministry of Water Resources, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China
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Li P, Sabarathinam C, Elumalai V. Groundwater pollution and its remediation for sustainable water management. CHEMOSPHERE 2023; 329:138621. [PMID: 37031835 DOI: 10.1016/j.chemosphere.2023.138621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Affiliation(s)
- Peiyue Li
- School of Water and Environment, Chang'an University, No.126 Yanta Road, Xi'an, 710054, Shannxi, China.
| | - Chidambaram Sabarathinam
- Water Research Center, Kuwait Institute for Scientific Research, P.O. Box 24885, Safat, 13109, Kuwait
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Feng B, Zhong Y, He J, Sha X, Fang L, Xu Z, Qi Y. Nitrogen sources and conversion processes in shallow groundwater around a plain lake (Northwest China): Evidenced by multiple isotopes and water chemistry. CHEMOSPHERE 2023:139322. [PMID: 37356584 DOI: 10.1016/j.chemosphere.2023.139322] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 06/20/2023] [Accepted: 06/23/2023] [Indexed: 06/27/2023]
Abstract
The groundwater quality is severely impacted by Nitrate (NO3--N) pollution worldwide. Effective lake quality management depends on understanding the origin and fate of nitrogen (N) in the groundwater around lakes. This study combined data for multiple stable isotopes (δ2H-H2O and δ18O-H2O, δ15N-NO3 and δ18O-NO3) and hydrochemistry with the hydrodynamic monitoring profile and a Bayesian isotope mixing (MixSIAR) model to clarify the sources and transformation of N within shallow groundwater around Shahu Lake in the arid area plain of Northwest China. In May 2022, multiple water samples were collected from aquifers (n = 33), drainage water (n = 1), channel water (n = 1), and lake water (n = 7). The results showed that 57% of groundwater samples had high NO3--N concentrations exceeding the World Health Organisation threshold for drinking water (10 mg/L). The high variation in δ15N-NO3 (from -9.21‰ to +27.57‰) and δ18O-NO3 (from -8.32‰ to +19.04‰) revealed multiple N sources and conversion processes. According to nitrate isotopes and the MixSIAR model, N fertilizer, soil organic N and manure, and sewage are the main sources of nitrogen in groundwater and lake water, which account for 40.61%, 35.86%, and 21.55% of groundwater NO3--N, respectively, and 35.07%, 34.43%, and 27.49% of lake water NO3--N. Hydrodynamic monitoring combined with water isotopes showed that upper groundwater (5-10 m) within 1.22 km of the adjacent lake shore strongly interacted with the lake. In groundwater, nitrification predominated, while local denitrification remained a possibility. In conclusion, this research offers a comprehensive approach to determining the sources and conversion of N in contaminated groundwater.
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Affiliation(s)
- Bo Feng
- School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan, Ningxia, 750021, China
| | - Yanxia Zhong
- School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan, Ningxia, 750021, China; Breeding Base for State Key Lab. of Land Degradation and Ecological Restoration in Northwestern China, Yinchuan, Ningxia, 750021, China; Key Lab. for Restoration and Reconstruction of Degraded Ecosystems in Northwestern China of Ministry of Education, Yinchuan, Ningxia, 750021, China.
| | - Jing He
- Breeding Base for State Key Lab. of Land Degradation and Ecological Restoration in Northwestern China, Yinchuan, Ningxia, 750021, China; Key Lab. for Restoration and Reconstruction of Degraded Ecosystems in Northwestern China of Ministry of Education, Yinchuan, Ningxia, 750021, China; School of Ecology and Environment, Ningxia University, Yinchuan, Ningxia, 750021, China
| | - Xiaohua Sha
- Ningxia Vocational Technical College of Industry and Commerce, Yinchuan, Ningxia, 750021, China
| | - Lei Fang
- Hydrology Environmental Geological Survey Institute of Ningxia Hui Autonomous Region, Yinchuan, Ningxia, 750021, China
| | - Zhaoxiang Xu
- Hydrology Environmental Geological Survey Institute of Ningxia Hui Autonomous Region, Yinchuan, Ningxia, 750021, China
| | - Yarong Qi
- School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan, Ningxia, 750021, China
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Sako A, Ouangaré CAC. Hydrogeochemical characterization and natural background level determination of selected inorganic substances in groundwater from a semi-confined aquifer in Midwestern Burkina Faso, West Africa. ENVIRONMENTAL MONITORING AND ASSESSMENT 2023; 195:519. [PMID: 36976429 DOI: 10.1007/s10661-023-11127-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/09/2023] [Indexed: 06/18/2023]
Abstract
Hydrogeochemical processes that govern selected inorganic substances distribution in a semi-confined aquifer were characterized using traditional hydrogeochemical approaches and natural background levels (NBLs). Saturation indices and bivariate plots were used to investigate the effects of water-rock interactions on natural evolution of the groundwater chemistry, whereas Q-mode hierarchical cluster analysis and one-way analysis of variance classified the groundwater samples into three distinct groups. To highlight the groundwater status, NBLs and threshold values (TVs) of the substances were calculated using pre-selection method. Piper's diagram showed that the Ca-Mg-HCO3 water type was the only hydrochemical facies of the groundwaters. Although all samples, except a borewell with a high NO3- concentration, had major ion and transition metal concentrations within the World Health Organization's recommended guideline values for drinking water, Cl-, NO3- and PO43- exhibited scattered distribution patterns, reflecting their nonpoint anthropogenic sources in the groundwater system. The bivariate and saturation indices revealed that silicate weathering and possible gypsum and anhydrite dissolution contributed to the groundwater chemistry. In contrast, NH4+, FeT and Mn abundance appeared to be influenced by redox conditions. Strong positive spatial correlations between pH, FeT, Mn and Zn suggested that mobility of these metals was controlled by pH. The relative high F- concentrations in lowland areas may imply the impact of evaporation on this ion's abundance. Contrary to TVs of HCO3-, those of Cl-, NO3-, SO42-, F- and NH4+ were below the guideline values, confirming the influence of chemical weathering on the groundwater chemistry. Based on the present findings, further studies that take into account more inorganic substances are required for NBLs and TVs determination in the area, thereby setting up a robust sustainable management plan for the regional groundwater resources.
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Affiliation(s)
- Aboubakar Sako
- UFR Sciences Appliquées et Technologie, Université de Dédougou, BP 139, Dédougou, Burkina Faso.
- Laboratoire Géosciences et Environnement (LaGE), Département des Sciences de la Terre, Université Joseph Ki-Zerbo, Ouagadougou, Burkina Faso.
| | - Cheik Abba Cissé Ouangaré
- Laboratoire Géosciences et Environnement (LaGE), Département des Sciences de la Terre, Université Joseph Ki-Zerbo, Ouagadougou, Burkina Faso
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