Migration of ammonium nitrogen in ion-absorbed rare earth soils during and post in situ mining: a column study and numerical simulation analysis
作者机构：Department of Environmental Science and EngineeringFudan UniversityShanghai 200438China School of Resource and Environmental EngineeringJiangxi University of Science and TechnologyGanzhou 341000China CAS Key Laboratory of Soil Environment and Pollution RemediationInstitute of Soil ScienceChinese Academy of SciencesNanjing 210008China National Observations and Research Station for Wetland Ecosystems of the Yangtze EstuaryShanghai 202151China Shanghai Institute of Pollution Control and Ecological SecurityShanghai 200001China
出 版 物：《环境科学与工程前沿(英文)》 (Frontiers of Environmental Science & Engineering)
年 卷 期：2023年第17卷第8期
页 面：137-151页
核心收录：
学科分类：09[农学] 0818[工学-地质资源与地质工程] 0903[农学-农业资源与环境]
基 金：the Financial of National Key Research and Development Project of China(No.2019YFC1805102) Partial supports are from the National Natural Science Foundation of China(Nos.42107228 and 41977266) Shanghai Pujiang Program(No.21PJ1401000)。
主 题：Ion-absorbed rare earth Ammonium nitrogen transport HYDRUS-2D Numerical simulation
摘 要：Ion-absorbed rare earth mines,leached in situ,retain a large amount of ammonium nitrogen(NH4–N)that continuously releases into the surrounding environments.However,quantitative descriptions and predictions of the transport of NH4–N across mining area with hill slopes are not fully established.Here,laboratory column experiments were designed with an inclined slope(a sand box)to examine the spatial temporal transport of NH4–N in soils collected from the ionic rare earth elements(REE)mining area.An HYDRUS-2D model simulation of the experimental data over time showed that soils had a strong adsorption capacity toward NH4–N.Chemical non-equilibrium model(CNEM)could well simulate the transport of NH4–N through the soil-packed columns.The simulation of the transport-adsorption processes at three flow rates of leaching agents revealed that low flow rate enabled a longer residence time and an increased NH4-N adsorption,but reduced the extraction efficiency for REE.During the subsequent rainwater washing process,the presence of slope resulted in the leaching of NH4–N on the surface of the slope,while the leaching of NH4–N deep inside the column was inhibited.Furthermore,the high-intensity rainfall significantly increased the leaching,highlighting the importance of considering the impact of extreme weather conditions during the leaching process.Overall,our study advances the understanding of the transport of NH4–N in mining area with hills,the impact of flow rates of leaching agents and precipitation intensities,and presents as a feasible modeling method to evaluate the environmental risks of NH4–N pollution during and post REE in situ mining activities.
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