Enrichment Characteristics of Nitrogen in Phreatic and Confined Groundwater along Middle Reaches of Yangtze River and Their Relationship with Flow Patterns
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摘要:
为了探究长江中游临江地下水中氮的赋存状态及地表水-地下水补排模式对氮富集的影响，对长江中游18个监测点两年8个季度的水文监测和288组水样分析，系统揭示了长江中游临江地下水中氮的富集特征及不同富集区中江水-潜水-承压水的补排模式的差异性.结果表明，长江中游临江地下水氮的富集差异性较大，研究区识别出高硝、高氨和低氮区3种氮的赋存模式；长江北侧地下水中氮的富集主要受氧化还原电位的调控，而南侧地下水中氮的富集受多种因素共同控制；高硝区主要出现在潜水有氮污染且潜水-承压水-江水均连通、以江水补给为主的承压水中；高氨区主要出现在潜水-承压水-江水间水力联系较弱或地下水向长江排泄为主的承压水中，不受潜水中氮污染的影响，其主要源于地质成因.该研究结果分别揭示了长江中游临江潜水和承压水中不同形态氮的富集特征及其与潜水-承压水-江水的连通性和补排关系之间的联系，为该区域氮的生物地球化学过程及氮来源解析提供了重要的科学依据.
Abstract:To explore the nitrogen distribution state and the influence of the surface water-groundwater recharge and discharge patterns on nitrogen enrichment in the groundwater along the Middle Reaches of Yangtze River, this study conducted hydrological monitoring for two years and analyzed 288 water samples at 18 monitoring points along the Middle Reaches of Yangtze River, systematically revealing the enrichment characteristics of nitrogen in the groundwater along the Middle Reaches of Yangtze River and the differences in recharge and discharge patterns of river - phreatic groundwater - confined groundwater in different enrichment areas. The results show that groundwater nitrogen concentrations exhibit significant variation. Three nitrogen distribution patterns were identified in the study area: high nitrate areas, high ammonia areas, and low nitrogen areas. The enrichment of nitrogen in groundwater on the northern side of the Yangtze River is mainly regulated by the redox potential, while the enrichment of nitrogen in groundwater on the southern side is controlled by multiple factors in combination. The high nitrate areas mostly occurs in confined groundwater, where nitrogen pollution is present in the upper phreatic groundwater and where phreatic groundwater, confined groundwater, and river water are connected, with river water as the primary source of replenishment. The high ammonia area mainly occurs in confined groundwater where the hydraulic connection among the phreatic groundwater, confined groundwater, and river water is weak or where groundwater discharges to the Yangtze River. It is not affected by nitrogen pollution in the phreatic groundwater and mainly originates from geological causes. The research results respectively reveal the enrichment characteristics of different forms of nitrogen in the phreatic groundwater and confined groundwater across the Middle Reaches of the Yangtze River and their connections with the connectivity and replenishment and discharge relationships among the phreatic groundwater, confined groundwater, and river water, providing essential scientific basis for the biogeochemical process of nitrogen and the source analysis of nitrogen in this area.
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图 1 研究区地理位置及采样点分布
Fig. 1. Location of the study area and distribution of sampling sites
图 2 长江中游各采样点总氮(a)、NO3-N(b)和NH4-N(c)的分布特征
Fig. 2. The distribution characteristics of total nitrogen (a), NO3-N (b) and NH4-N (c) at each sampling point in the Middle Reaches of the Yangtze River
图 3 长江中游侧向地下水中氮富集区的空间分布
Fig. 3. Spatial distribution of nitrogen-enriched areas in groundwater in the Middle Reaches of the Yangtze River
图 5 长江南北两侧地下水样品中NO3-N、NH4-N与氧化还原电位的线性回归分析
Fig. 5. Linear regression analysis of NO3-N, NH4-N and oxidation-reduction potential in groundwater samples from both sides of the Yangtze River
图 6 高硝点的潜水-承压水-长江水位变化
Fig. 6. Water level changes of the phreatic groundwater-the confined groundwater-the Yangtze River with high nitrate
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Chen, J., Qian, H., Wu, H., 2017. Nitrogen Contamination in Groundwater in an Agricultural Region along the New Silk Road, Northwest China: Distribution and Factors Controlling Its Fate. Environmental Science and Pollution Research, 24(15): 13154-13167. https://doi.org/10.1007/s11356-017-8881-0 Du, Y., Deng, Y. M., Ma, T., et al., 2020. Enrichment of Geogenic Ammonium in Quaternary Alluvial–Lacustrine Aquifer Systems: Evidence from Carbon Isotopes and DOM Characteristics. Environmental Science Technology, 54(10): 6104-6114. https://doi.org/10.1021/acs.est.0c00131 Du, Y., Ma, T., Deng, Y. M., et al., 2017. Sources and Fate of High Levels of Ammonium in Surface Water and Shallow Groundwater of the Jianghan Plain, Central China. Environmental Science: Processes Impacts, 19(2): 161-172. https://doi.org/10.1039/C6EM00531D Gan, Y. Q., Zhao, K., Deng, Y. M., et al., 2018. Groundwater Flow and Hydrogeochemical Evolution in the Jianghan Plain, Central China. Hydrogeology Journal, 26(5): 1609-1623. https://doi.org/10.1007/s10040-018-1778-2 Guo, H. M., Li, G. H., Zhang, D. Y., et al., 2006. Effects of Water Table and Fertilization Management on Nitrogen Loading to Groundwater. Agricultural Water Management, 82(1-2): 86-98. https://doi.org/10.1016/j.agwat.2005.07.033 Hu, M. Y., Zhou, P. J., Chen, C. Q., 2023. Study on Coupling of Typical Elements in Surface Water and Groundwater in the Middle Reaches of the Yangtze River, China. Journal of Hydrology, 626: 130298. https://doi.org/10.1016/j.jhydrol.2023.130298 Kiel, B. A., Cardenas, M. B., 2014. Lateral Hyporheic Exchange throughout the Mississippi River Network. Nature Geoscience, 7(6): 413-417. https://doi.org/10.1038/ngeo2157 Kumar, B. S. K., Sridevi, B., Sarma, V. V. S. S., et al., 2024. Isotopic Evidence of Denitrified Nitrate in Groundwater beneath Intensive Agriculture and Exchange with Estuary (Godavari, India). ACS EST Water, 4(8): 3521-3531. https://doi.org/10.1021/acsestwater.4c00338 Liang, Y., Ma, R., Nghiem, A., et al., 2022. Sources of Ammonium Enriched in Groundwater in the Central Yangtze River Basin: Anthropogenic or Geogenic? Environmental Pollution, 306: 119463. https://doi.org/10.1016/j.envpol.2022.119463 Liang, Y., Ma, R., Wang, Y. X., et al., 2020. Hydrogeological Controls on Ammonium Enrichment in Shallow Groundwater in the Central Yangtze River Basin. Science of the Total Environment, 741: 140350. https://doi.org/10.1016/j.scitotenv.2020.140350 Liu, X. C., Beusen, A. H. W., Van Beek, L. P. H., et al., 2018. Exploring Spatiotemporal Changes of the Yangtze River (Changjiang) Nitrogen and Phosphorus Sources, Retention and Export to the East China Sea and Yellow Sea. Water Research, 142: 246-255. https://doi.org/10.1016/j.watres.2018.06.006 Liu, Y. Y., Liu, C. X., Nelson, W. C., et al., 2017. Effect of Water Chemistry and Hydrodynamics on Nitrogen Transformation Activity and Microbial Community Functional Potential in Hyporheic Zone Sediment Columns. Environmental Science Technology, 51(9): 4877-4886. https://doi.org/10.1021/acs.est.6b05018 Niu, B. B., Wang, H. H., Loáiciga, H. A., et al., 2017. Temporal Variations of Groundwater Quality in the Western Jianghan Plain, China. Science of the Total Environment, 578: 542-550. https://doi.org/10.1016/j.scitotenv.2016.10.225 Sun, L. Q., Liang, X., Jin, M. G., et al., 2021. Ammonium and Nitrate Sources and Transformation Mechanism in the Quaternary Sediments of Jianghan Plain, China. Science of the Total Environment, 774: 145131. https://doi.org/10.1016/j.scitotenv.2021.145131 Zhou, Y., Wang, Y. X., Li, Y. L., et al., 2013. Hydrogeochemical Characteristics of Central Jianghan Plain, China. Environmental Earth Sciences, 68(3): 765-778. https://doi.org/10.1007/s12665-012-1778-9 Zuo, R., Zheng, S. D., Liu, X., et al., 2023. Groundwater Table Fluctuation: A Driving Force Affecting Nitrogen Transformation in Nitrate-Contaminated Groundwater. Journal of Hydrology, 621: 129606. https://doi.org/10.1016/j.jhydrol.2023.129606 -
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