地学前缘 ›› 2025, Vol. 32 ›› Issue (4): 510-522.DOI: 10.13745/j.esf.sf.2024.6.37

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华北平原浅层地下水碘的分区特征及成因研究

黄诗雯1(), 夏绮文1, 何江涛1,*(), 何宝南1, 陈翠柏1, 孙继朝2   

  1. 1.中国地质大学(北京) 水利部地下水保护重点实验室(筹), 北京 100083
    2.中国地质科学院水文地质环境地质研究所, 河北 石家庄 050061
  • 收稿日期:2024-01-31 修回日期:2024-03-26 出版日期:2025-07-25 发布日期:2025-08-04
  • 通信作者: *何江涛(1974—),男,教授,主要研究方向为污染水文地质学。E-mail:jthe@cugb.edu.cn
  • 作者简介:黄诗雯(1999—),女,硕士,主要研究方向为水文地质与工程地质。E-mail:17302418319@163.com
  • 基金资助:
    自然资源部国土资源大调查项目“全国地下水污染综合调查评价”(1212011121170)

Study on zoning characteristics and genesis of iodine in shallow groundwater in North China Plain

HUANG Shiwen1(), XIA Qiwen1, HE Jiangtao1,*(), HE Baonan1, CHEN Cuibai1, SUN Jichao2   

  1. 1. Key Laboratory of Groundwater Conservation of Ministry of Water Resources, China University of Geosciences (Beijing), Beijing 100083, China
    2. Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang 050061, China
  • Received:2024-01-31 Revised:2024-03-26 Online:2025-07-25 Published:2025-08-04

摘要:

本文以华北平原浅层地下水为研究对象,基于地下水系统分区和海侵历史,以及碘的浓度分布特征,划分出4个典型区域:海河平原地下水系统区(A)、海河平原地下水系统-海侵区(B)、古黄河下游地下水系统区(C)和古黄河下游地下水系统-海侵区(D)。总体而言,华北平原浅层地下水整体呈近中性-偏碱性,碘离子浓度分布具有明显的分带性,从山前地带到滨海区,地下水中碘离子浓度呈明显上升趋势,水化学类型也出现由低TDS的HCO3-Ca型水(A),到TDS高于1 g/L的HCO3-Na型水(C),再到TDS高于3 g/L的Cl-Na型水(B、D)。高碘地下水主要分布在B、C和D区,其碘离子浓度平均值分别为128.27、176.7和179.2 μg/L,且C和D区的中位数值均超过100 μg/L。针对3个高碘区域,筛选碘的影响因子,运用随机森林等方法初步探讨了研究区内高碘地下水的成因。结果显示: C区属于中TDS-高碘区,该区由于黄河多期泛滥沉积形成了复杂的黏土和砂土互层现象,地下水循环弱,碘离子的浓度与冲积湖沉积物中有机质、黏土矿物和铁氧化物含量有关,高碘地下水形成的主要作用为蒸发浓缩。D区为高TDS-高碘区,历史上发生的海侵事件使得大量的碘储存在沉积物中,为地下水中的碘提供了来源,有机质的生物降解作用是该区高碘地下水形成的主要驱动因素。B区属于高TDS-中碘区,历次海侵事件形成的海相沉积物同样是该地区含水层中碘的来源,九河下梢的淋滤作用使该区的碘浓度要略低于D区。

关键词: 地下水, 高碘, 分区, 水文地质条件

Abstract:

In this paper, the shallow groundwater in the North China Plain is taken as the object of study, and based on the zoning of the groundwater system and the history of sea intrusion, as well as the characteristics of the iodine concentration distribution, four typical zones are delineated:Haihe Plain Groundwater System Zone (A); Haihe Plain Groundwater System-Sea Intrusion Zone (B); Lower Paleo-Yellow River Groundwater System Zone (C); and Lower Paleo-Yellow River Groundwater System-Sea Intrusion Zone (D). Overall, the shallow groundwater in the North China Plain was nearly neutral to alkaline,and the distribution of iodine ion concentration was clearly zoned, with a clear upward trend in iodine ion concentration from the pre-mountainous area to the coastal area, and the hydrochemical type of the water also appeared to vary from HCO3-Ca type water with a low TDS (A) to HCO3-Na type water with a TDS of more than 1 g/L (C),to Cl-Na type water with a TDS of more than 3 g/L (B,D). The high iodine groundwater were mainly distributed in zones B, C, and D, with mean iodine ion concentrations of 128.27 μg/L, 176.7 μg/L, and 179.2 μg/L respectively, and the median values of zones C and D were more than 100 μg/L. For the three high iodine zones, we screened the iodine-influencing factors and preliminarily explored the causes of the high iodine groundwater in the study area by using the method of random forest. The results showed that Zone C belongs to the medium TDS-high iodine zone, where the complex clay and sand interlayer phenomenon was formed due to the deposition of the Yellow River in multiple flooding periods, the groundwater circulation is weak, the concentration of iodine ions is related to the content of organic matter, clay minerals and iron oxides in the alluvial lake sediments, and the main role of the formation of high iodine groundwater is the evaporation and concentration. Zone D belongs to the high TDS-high iodine zone, and the sea invasion events in the past made a large amount of iodine stored in the sediments, and the formation of high iodine groundwater is mainly due to evaporation and concentration. Area D is a high TDS-moderate iodine area, and the historical marine intrusion events have caused a large amount of iodine to be stored in the sediments, providing a source of iodine in the groundwater, and the biodegradation of organic matter is the main driving factor for the formation of high iodine groundwater in this area. Area B belongs to the high TDS-moderate iodine area, and the marine sediment formed by the historical marine intrusion events is also the source of iodine in the aquifer in this area, and the iodine concentration of the area is slightly lower than that of Area D because of leaching from the lower tip of the Nine Rivers.

Key words: groundwater, high iodine, partition, hydrogeological conditions

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