地学前缘 ›› 2026, Vol. 33 ›› Issue (1): 14-24.DOI: 10.13745/j.esf.sf.2025.10.35

• 地下水-关键带相互作用与修复 • 上一篇    下一篇

水库水位变动影响下消落带沉积物氮磷吸附-解吸行为与释放通量估算

吴默涵1,2,3(), 苏小四1,2,3, 宋铁军1,2,3,*(), 郝源1,2,3   

  1. 1.吉林大学 新能源与环境学院, 吉林 长春 130021
    2.吉林大学 地下水资源与环境教育部重点实验室, 吉林 长春 130021
    3.吉林大学 水资源与环境研究所, 吉林 长春 130021
  • 收稿日期:2025-06-20 修回日期:2025-09-12 出版日期:2026-01-25 发布日期:2025-11-10
  • 通信作者: *宋铁军(1991—),男,博士,副教授,主要从事水循环与生态过程、水文地球化学等方面研究。E-mail: songtiejun@jlu.edu.cn
  • 作者简介:吴默涵(2001—),女,硕士研究生,土木水利专业,主要从事地下水资源评价方面研究。E-mail: m15568570337@163.com
  • 基金资助:
    国家自然科学基金项目(42230204);吉林省环境保护科研项目(吉环科字第2023-02号)

Adsorption-desorption behavior and release flux of nitrogen and phosphorus in sediments of the reservoir drawdown zone under water level fluctuations

WU Mohan1,2,3(), SU Xiaosi1,2,3, SONG Tiejun1,2,3,*(), HAO Yuan1,2,3   

  1. 1. College of New Energy and Environment, Jilin University, Changchun 130021, China
    2. Laboratory of Groundwater Resources and Environment of the Ministry of Education, Jilin University, Changchun 130021, China
    3. Institute of Water Resources and Environment, Jilin University, Changchun 130021, China
  • Received:2025-06-20 Revised:2025-09-12 Online:2026-01-25 Published:2025-11-10

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摘要：

水库水位变动而形成的消落带作为水陆交错带的关键界面,其沉积物氮磷释放是影响水库水质的重要因素。然而,周期性水位变动引发的消落带氧化还原环境交替变化导致消落带氮磷的释放行为及其对水库水质的影响贡献尚不完全清楚。本研究以吉林省某大型水库为研究对象,通过采集淹水前、淹水期和退水期水库地表水和消落带沉积物样品,阐明水位变动下消落带沉积物氮磷释放规律及其对水库水质影响的贡献。研究结果表明:在整个水位波动周期(淹水前—淹水期—退水期),库水氨氮和磷酸根浓度呈现先增加后减小的趋势。沉积物氨氮含量先降低后升高,而无机磷含量则先增加后降低。吸附-解吸实验表明酸性条件下(pH=5)沉积物对氨氮和磷酸盐的吸附量较大,而碱性条件(pH=9)下沉积物氮磷解吸作用较强。在退水期,沉积物对氮磷表现出较强的解吸作用。质量平衡法表明,沉积物氮和磷的释放通量分别为324.15 t和8.18 t,其对水库地表水无机氮、磷变化的贡献率分别高达47.22%和57.72%。本项研究对于识别水库内源污染机制,预测水环境风险,保障居民饮水安全和推动水资源可持续管理提供重要科学依据。

关键词: 水库消落带, 水位波动, 氮磷含量, 释放通量, 吸附-解吸

Abstract:

The drawdown zone, formed by water-level fluctuations in reservoirs, represents a critical terrestrial-aquatic interface. The release of nitrogen and phosphorus from its sediments significantly influences reservoir water quality. However, the alternating redox conditions caused by periodic water-level fluctuations lead to poorly understood mechanisms governing the release of these nutrients and their contribution to water quality. This study was conducted in a large-scale reservoir in Jilin Province. Water and sediment samples from the drawdown zone were collected during the pre-flood, flood, and post-flood periods to investigate the release patterns of nitrogen and phosphorus in response to water-level fluctuations and their impact on reservoir water quality. The results showed that during the water-level fluctuation cycle, the concentrations of ammonia nitrogen (${\mathrm{NH}}_{4}^{+}$-N) and phosphate (${\mathrm{PO}}_{4}^{3-}$-P) in the reservoir water first increased and then decreased. In the sediments, ammonia nitrogen content initially decreased and then increased, while inorganic phosphorus content showed an opposite trend. Adsorption-desorption experiments revealed that at pH 5, the sediments had a high adsorption capacity for both ammonia nitrogen and phosphate. In contrast, at pH 9, the desorption of nitrogen and phosphorus was enhanced. Notably, during the post-flood period, the sediments exhibited significant desorption behavior. Mass balance calculations indicated that the release fluxes of nitrogen and phosphorus from the sediments were 324.15 t and 8.18 t, accounting for 47.22% and 57.72% of the variations in inorganic nitrogen and phosphorus concentrations in the surface water, respectively. This study provides crucial scientific evidence for identifying internal pollution mechanisms in reservoirs, predicting water quality risks, and supporting sustainable water resource management and drinking water safety.

Key words: reservoir drawdown zone, water level fluctuation, nitrogen and phosphorus contents, release flux, adsorption-desorption

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