The migration and transformation of NH4-N are influenced by the interactions between surface water and groundwater.However,the mechanisms remain poorly understood.Continuous monitoring of the water level and its hydrochemical composition was conducted in the Shahu site.Column experiments and reactive transport modeling were applied to identify the migration and transformation of NH4-N under conditions of both surface water recharge and groundwater discharge.In this study it indicates that most injected NH4-N is adsorbed on shallow sediment.Infiltration of surface water enhances desorption of NH4-N from sediment particle and subsequent nitrification reactions.In contrast,adsorption of NH4-N on sediment is favored during discharge of NH4-N containing groundwater.Simulating results emphasize the crucial role of cation exchange in NH4-N mobility.Alterations in the hydrogeochemical environment during surface water-groundwater interactions impact the NH4-N adsorption/desorption behaviors and associated biogeochemical reactions.
关键词
铵态氮/离子交换/反应迁移模型/地表水/地下水/江汉平原/水文地质学
Key words
ammonium nitrogen/ion exchange/reactive transport modeling/surface water/groundwater/Jianghan Plain/hydrogeology
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