地学前缘 ›› 2024, Vol. 31 ›› Issue (3): 360-370.DOI: 10.13745/j.esf.sf.2023.2.84

• 地下水与地热资源 • 上一篇    下一篇

赣抚平原东北部地下水硝酸盐浓度变化特征及成因

何佳汇1,2(), 毛海如1,*(), 薛洋3, 廖福1, 高柏4, 饶志5, 杨扬5, 刘媛媛4, 王广才1,*()   

  1. 1.中国地质大学(北京) 生物地质与环境地质国家重点实验室/地下水循环与环境演化教育部重点实验室, 北京 100083
    2.北京市工程地质研究所, 北京 100048
    3.中国水务投资有限公司, 北京 100053
    4.东华理工大学 水资源与环境工程学院, 江西 南昌 330013
    5.江西省地质调查勘查院地质环境监测所, 江西 南昌 330006
  • 收稿日期:2022-12-17 修回日期:2023-04-13 出版日期:2024-05-25 发布日期:2024-05-25
  • 通信作者: *毛海如(1995—),女,博士,水文地质专业,主要研究方向为地下水污染。E-mail: 717321897@qq.com; 王广才(1962—),男,博士,教授,主要从事水文地质学方面的教学与科研工作。E-mail: wanggc@cugb.edu.cn
  • 作者简介:何佳汇(1996—),女,硕士,助理工程师,地质工程专业,主要研究方向为水文地球化学。E-mail:376408031@qq.com
  • 基金资助:
    国家自然科学基金重点项目(42030705)

Variability in spatiotemporal groundwater nitrate concentrations in the northeast Ganfu Plain

HE Jiahui1,2(), MAO Hairu1,*(), XUE Yang3, LIAO Fu1, GAO Bai4, RAO Zhi5, YANG Yang5, LIU Yuanyuan4, WANG Guangcai1,*()   

  1. 1. State Key Laboratory of Biogeology and Environmental Geology/MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
    2. Beijing Institute of Geo-Engineering, Beijing 100048, China
    3. China Water Investment Co., Ltd., Beijing 100053, China
    4. School of Water Resources & Environmental Engineering, East China Institute of Technology, Nanchang 330013, China
    5. Geological Environment Monitoring Institute of Jiangxi Geological Survey and Exploration Institute, Nanchang 330006, China
  • Received:2022-12-17 Revised:2023-04-13 Online:2024-05-25 Published:2024-05-25

摘要:

赣抚平原地下水硝酸盐含量较高,但目前对地下水水化学组分(特别是硝酸盐)浓度的季节变化特征及其影响因素的研究还较少。本文通过采集赣抚平原东北部枯、丰水期地下水样品,运用水化学图解法、自组织神经网络(SOM)、空间自相关分析及反向水文地球化学模拟等方法,对研究区地下水化学组分(特别是硝酸盐)浓度的时空变化及硝酸盐来源进行研究。研究结果表明,研究区地下水化学类型以Cl·NO3-Ca型、HCO3-Ca型为主,人类活动的输入是引起地下水化学空间分布差异的主要因素。NO3-浓度较高以及季节变化较大的地区均集中于南昌下游。NO3-浓度低值区和季节变化的低值区主要分布在西部、东南部的山区以及赣江三角洲下游。地下水NO3-浓度的空间分布特征和季节变化特征与地下水径流特征、氧化还原环境和土地利用类型有关。地下水中NO3-主要来源于工业、生活污水,农业化肥对地下水NO3-的影响也不可忽视。反向水文地球化学模拟结果定量揭示了地下水径流过程中所受水-岩作用和人类活动的影响。

关键词: 地下水, 硝酸盐污染, 时空变化, 水化学演化

Abstract:

Groundwater in the Ganfu Plain exhibits high NO3- concentrations, yet few studies have investigated the seasonal variations and influencing factors of groundwater chemistry, particularly NO3- concentrations. In this study, groundwater samples were collected in the northeast region of the Ganfu Plain during both dry and wet seasons. The study aimed to explore the spatiotemporal variations in groundwater chemistry, focusing on NO3- concentrations, and the sources of NO3- in groundwater using hydrochemical diagrams, Self-Organizing Map (SOM), spatial autocorrelation analysis, and an inverse geochemical model. The results indicate that the primary groundwater types in the study area are Cl·NO3-Ca and HCO3-Ca. Human activities emerge as the key factor driving spatial variations in groundwater chemistry. Regions with elevated NO3- concentrations and significant seasonal variations are predominantly located in the lower reaches of Nanchang. Conversely, areas with lower NO3- concentrations and seasonal variations are primarily situated in the western and southeastern mountainous regions and the lower reaches of the Ganjiang River Delta. The spatial distribution and seasonal variability of groundwater NO3- concentrations in the study area are influenced by groundwater runoff conditions, redox environments, and land use patterns. Industrial and domestic sewage are identified as the main sources of NO3- in groundwater, with the impact of fertilizers on NO3- concentrations also warranting consideration. The results from the inverse geochemical model provide quantitative insights into the effects of water-rock interactions and human activities on groundwater quality during groundwater movement processes.

Key words: groundwater, nitrate pollution, spatiotemporal variation, hydrochemical evolution

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