傍河水源地地下水氧化还原分带及氨氮的迁移转化机理

Redox zonations is the basic characteristic of riverbank filtration system, and controlling the transport and transformation of infiltrated contaminants, Groundwater pumping making the spatial and temporal distribution of redox zonation changing a lot, and making the transport and transformation of redox senstive pollutants more complicated. Aiming at the lack of study on how the change of redox zonation caused by riverbank exploitation affects the mobilization processes of redox senstive contaminants, this study will select Gaojiadian as the study area,which locates beside Songhua River, and ammonia would be selected as the target redox senstive contaminant in this study, This study focuses on the influences of ammonia mobilization by changes in redox zonation,hydrodynamic exchange between river water and groundwater, according to the study route of field survey-experiments in lab-mechanism analysis-mathematical modeling, methodologies from multidisciplinary are ready to be used in this study, such as hydrogeology,hydrogeochemistry, environmental isotopes and molecular microbiology, this studywill discover the influence mechanisms of hydrodynamic condition change on the redox zonation and the redox conditions changes on the mobilization of the ammonia, predict the spatial and temporal distribution of ammonia in the riverbank filtration systems.

氧化还原分带是傍河水源地地下水的基本特征，是污染物入渗后迁移转化的关键控制因素，傍河取水使得氧化还原分带时空分布发生巨大变化，氧化还原敏感性污染物的迁移转化更加复杂。针对傍河取水过程中氧化还原分带变化如何影响氧化还原敏感性污染物迁移转化方面的研究不足，本项目拟选择高家店水源地为研究区，以河水中污染程度最高、危害最大的氧化还原敏感性污染物氨氮为研究对象，以傍河取水条件下水动力条件和氧化还原条件变化对氨氮迁移转化的影响为切入点，按照野外调查-室内实验-机理分析-数值模拟的研究思路，采用水文地质、水文地球化学、环境同位素、分子微生物等多学科交叉的技术手段，揭示傍河取水对氧化还原分带的影响机制和氨氮在不同氧化还原条件下的迁移转化机理，预测傍河水源地地下水中氨氮的时空分布趋势。

傍河取水过程中的氧化还原条件变化对氨氮的迁移转化具有显著影响。本次研究按照野外调查-室内实验-机理分析-数值模拟的研究思路，采用水文地质、水文地球化学、环境同位素、分子微生物等多学科交叉的技术手段，开展了典型傍河水源地的水文地质结构特征调查与分析，获得傍河水源地地表水-地下水交换特征，并划分了傍河水源地地下水氧化还原分带，开展了地下水中氨氮迁移转化室内模拟实验和吸附实验，对比分析了氧化还原条件变化和微生物存在条件下对氨氮迁移转化的影响，开展了基于同位素技术的氮源解析，识别出不同污染源的贡献比例，建立了地下水溶质运移模型，预测了地下水中氨氮迁移转化趋势。研究成果可以为傍河水源地的选址、设计、建设和运行提供科学依据。