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Chen Q, Chen A, Min J, Li L, Hu W, Wang C, Fu B, Guo S, Zhang D. Shallow groundwater table fluctuations weaken nitrogen accumulation in the thin layer vadose zone of cropland around plateau lakes, Southwest China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 950:175300. [PMID: 39111447 DOI: 10.1016/j.scitotenv.2024.175300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 07/09/2024] [Accepted: 08/03/2024] [Indexed: 08/10/2024]
Abstract
Excessive accumulation of nitrogen (N) in the soil profile in the intensive agricultural region will seriously threaten groundwater quality and safety. However, the impact of shallow groundwater table (SGWT) fluctuations driven by seasonal variations on the N accumulation characterizations in the soil profiles has not been well quantified, particularly in the regions with thin layer vadose zone. Through in-situ monitoring and simulation experiments, the changes in the SGWT and N accumulation of soil profile in intensive cropland around 7 plateau lakes in Yunnan were studied during the rainy season (RS) and dry season (DS), and the N loss in soil profile of cropland driven by SGWT fluctuations was estimated. The results showed that the SGWT and N accumulation in soil profile of cropland around the plateau lakes had obvious seasonal variation characteristics. The proportion of N storage in different forms in 60-100 cm soil layer in the RS was greater than that in the DS, particularly the proportion of NH4+-N storage was as high as 55 %, while N accumulation in surface soil was obvious in the DS. Compared with the DS, due to the rising SGWT in the RS, the maximum storages of TN and NO3--N in the 0-100 cm soil layer decreased by17% and 36 %, respectively. The TN loss intensities from the 0-100 cm soil profiles of cropland around Fuxian Lake, Yilong Lake, Qilu Lake, Dianchi Lake, Yangzong Lake, Erhai Lake, and Xingyun Lake were 74, 54, 127, 105, 93, 72 and 207 kg/ha, respectively. Moreover, if the SGWT was <30 cm, the average TN loss intensity and amount could reach 177 kg/ha and 1250 t, respectively. Therefore, the SGWT regulation was one of the key measures to reducing soil N loss from the thin layer vadose zone of cropland around plateau lakes and improving groundwater quality.
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Affiliation(s)
- Qingfei Chen
- College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China; Agricultural Environment and Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming 650201, China
| | - Anqiang Chen
- Agricultural Environment and Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming 650201, China.
| | - Jinheng Min
- College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China
| | - Lin Li
- College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China
| | - Wanli Hu
- Agricultural Environment and Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming 650201, China
| | - Chi Wang
- Agricultural Environment and Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming 650201, China
| | - Bin Fu
- Agricultural Environment and Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming 650201, China
| | - Shufang Guo
- Agricultural Environment and Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming 650201, China
| | - Dan Zhang
- College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China.
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Wei Y, Chen Y, Cao X, Xiang M, Huang Y, Li H. A Critical Review of Groundwater Table Fluctuation: Formation, Effects on Multifields, and Contaminant Behaviors in a Soil and Aquifer System. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:2185-2203. [PMID: 38237040 DOI: 10.1021/acs.est.3c08543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
The groundwater table fluctuation (GTF) zone is an important medium for the hydrologic cycle between unsaturated soil and saturated aquifers, which accelerates the migration, transformation, and redistribution of contaminants and further poses a potential environmental risk to humans. In this review, we clarify the key processes in the generation of the GTF zone and examine its links with the variation of the hydrodynamic and hydrochemistry field, colloid mobilization, and contaminant migration and transformation. Driven by groundwater recharge and discharge, GTF regulates water flow and the movement of the capillary fringe, which further control the advection and dispersion of contaminants in soil and groundwater. In addition, the formation and variation of the reactive oxygen species (ROS) waterfall are impacted by GTF. The changing ROS components partially determine the characteristic transformation of solutes and the dynamic redistribution of the microbial population. GTF facilitates the migration and transformation of contaminants (such as nitrogen, heavy metals, non-aqueous phase liquids, and volatile organic compounds) through colloid mobilization, the co-migration effect, and variation of the hydrodynamic and hydrochemistry fields. In conclusion, this review illustrates the limitations of the current literature on GTF, and the significance of GTF zones in the underground environment is underscored by expounding on the future directions and prospects.
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Affiliation(s)
- Yaqiang Wei
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Yuling Chen
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Xinde Cao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Minghui Xiang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Yuan Huang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Hui Li
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
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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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Gao H, Yang L, Song X, Guo M, Li B, Cui X. Sources and hydrogeochemical processes of groundwater under multiple water source recharge condition. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166660. [PMID: 37657547 DOI: 10.1016/j.scitotenv.2023.166660] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [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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Zang Y, Hou X, Li Z, Li P, Sun Y, Yu B, Li M. Quantify the effects of groundwater level recovery on groundwater nitrate dynamics through a quasi-3D integrated model for the vadose zone-groundwater coupled system. WATER RESEARCH 2022; 226:119213. [PMID: 36240711 DOI: 10.1016/j.watres.2022.119213] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 10/03/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
Groundwater level (GWL) recovery in some semiarid regions, attributed to mitigation countermeasures for groundwater depletion, potentially causes nitrate accumulated in the vadose zone to be introduced into the aquifer. However, the extent to which GWL recovery affects interactions between the vadose zone and saturated aquifers, migration pathways of soil nitrogen and groundwater nitrate dynamics have not been explicitly determined. This study established a quasi-3D feedback model for the vadose zone-groundwater coupled system in a typical GWL recovery area and quantitatively evaluated the effects of GWL recovery on nitrate-N leaching fluxes via the vadose zone and groundwater nitrate-N dynamics. Within the framework of the integrated model, both the water/contaminant leaching fluxes and the depth to groundwater were exchanged at each flow time step. The obtained results reveal that the temporal changes in nitrate-N leaching fluxes depended on the behaviors of precipitation, farmland irrigation and lithology of the vadose zone, while its spatial patterns were determined by both the GWL undulation and the vertical profiles of nitrate-N content. Furthermore, the GWL recovery caused the magnitude of the nitrate-N leaching fluxes into the aquifer to increase by 44.4%. Along with the GWL recovery, the phreatic aquifer volume increased by 7.47%, and the nitrate-N mass herein increased by 40.06%, which was largely driven by the nitrate-N leaching flux. Consequently, the average groundwater nitrate-N concentration in the GWL recovery region increased by approximately 2.4 mg/L, apart from the artificial recharge route. This finding suggests that the intensified leaching of soil contaminants, given the circumstances of GWL recovery, has a negative effect on groundwater quality. An appropriate groundwater management scheme is therefore urgently required to achieve an optimal balance between GWL recovery and groundwater environment.
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Affiliation(s)
- Yongge Zang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; School of Environment, Tsinghua University, Beijing, 100084, China
| | - Xiaoshu Hou
- Chinese Academy of Environmental Planning, Beijing, 100012, China.
| | - Zhiping Li
- Beijing Institute of Hydrogeology and Engineering Geology, Beijing, 100195, China
| | - Peng Li
- Beijing Institute of Hydrogeology and Engineering Geology, Beijing, 100195, China
| | - Ying Sun
- Beijing Institute of Hydrogeology and Engineering Geology, Beijing, 100195, China
| | - Bowei Yu
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Miao Li
- School of Environment, Tsinghua University, Beijing, 100084, China.
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