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现代地质 ›› 2022, Vol. 36 ›› Issue (02): 533-542.DOI: 10.19657/j.geoscience.1000-8527.2022.006

• 水资源与环境地质 • 上一篇    下一篇

氧化还原动态变化对沉积物砷和氟释放的影响:以河北白洋淀平原为例

曹元元(), 郭华明(), 高志鹏   

  1. 中国地质大学(北京) 水资源与环境学院,北京 100083
  • 收稿日期:2021-10-20 修回日期:2022-03-01 出版日期:2022-04-10 发布日期:2022-06-01
  • 通讯作者: 郭华明
  • 作者简介:郭华明,男,教授,博士生导师,1975年出生,水文地质学专业,从事水文地质学方面的教学与科研工作。Email: hmguo@cugb.edu.cn
    曹元元,女,博士研究生,1999年出生,水文地质学专业,主要从事水文地质学研究工作。Email:yuanyuancao1110@163.com
  • 基金资助:
    摄入途径及治理技术”(41861144027);国家杰出青年科学基金项目“水文地质学”(41825017)

Redox Dynamic Effect on Fluoride and Arsenic Released from Sediments in the Baiyangdian Plain, Hebei

CAO Yuanyuan(), GUO Huaming(), GAO Zhipeng   

  1. School of Water Resources and Environment, China University of Geosciences, Beijing 100083, China
  • Received:2021-10-20 Revised:2022-03-01 Online:2022-04-10 Published:2022-06-01
  • Contact: GUO Huaming

摘要:

季风性波动引起的降雨、径流和排泄过程会引发浅层地下水系统周期性氧化还原动态变化,从而对地下水系统中有害组分的迁移转化产生影响。为探讨氧化还原动态过程对沉积物中砷(As)和氟(F)释放的影响,本研究选择河北白洋淀地区沉积物样品,利用发酵罐作为反应器,建立氧化还原动态实验体系,并监测动态变化过程中实验体系各组分含量的变化。结果表明,碱性和还原环境均有利于地下水中As、F的富集。还原阶段较高的pH条件有利于溶液中F-的解吸,且体系中有机物降解会产生大量HC03-和C032-,与F-发生竞争吸附而有利于F-的富集。对于溶液中As的富集,一方面是由于还原条件下体系中的As以As(III)为主,受沉积物的吸附作用较弱,从而有利于As被释放到溶液中;另一方面是因为还原阶段较高的pH也会使反应体系中As和沉积物间的吸附作用被减弱,造成As的解吸附。由于实验所用沉积物砷含量较低,不同S042-浓度条件对氧化还原动态过程中As、F迁移的影响不明显。总之,氧化还原动态变化过程会强烈影响地下水系统中砷、氟的富集。

关键词: 白洋淀平原, 氧化还原动态, 砷,

Abstract:

Precipitation, discharge and draining caused by seasonal fluctuations would generate redox oscillations in shallow groundwater system, which may shed light on the reactive transport of groundwater components in aquifers. To explore the influence of redox oscillations on the release of arsenic and fluoride in sediments, a sediment sample from the Baiyangdian Plain was collected for this study. Variations in aerobic/anaerobic conditions were controlled automatically. During the redox oscillations, solution composition changes in each experimental system were monitored. Results suggest that the groundwater As-F enrichment was promoted by the alkaline and reducing conditions. The reason may be that the pH is higher under reducing conditions, which is conducive to F- enrichment. In addition, DOM degradation produced large amount of HC03- and C032- in solution, which benefits groundwater F- enrichment via competition. Since As (III) adsorption onto sediments is weaker than that of As (V), the dominant As (III) species in reducing solution would promote As mobility. Furthermore, the higher pH reduces the As adsorption capacity onto sediments, which causes As desorption. We found that the varying S042- concentrations show no clear effect on the As-F enrichment in the dynamically redox experiments. To conclude, the dynamic redox changes would strongly affect the enrichment of As and F- in groundwater.

Key words: Baiyangdian Plain, redox oscillation, arsenic, fluoride

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