稀土矿区典型流域水沙过程与氨氮及重金属多界面迁移机制研究

It has been one of the hottest subjects for scientific research in recent years of the environment and ecological problems in the basin of rare earth mining area. The unique geomorphology and the pressing water resource protection in this region make it important both theoretically and practically to study the water and sediment processes and migration and transformation mechanism of heavy metal elements in the basin.. In this project, the Taojiang River Basin is selected as the study site where the process of water and sediment movement, ammonia nitrogen and the migration and enrichment of major heavy metal elements will be investigated and observed in field. Correlation analysis, principal component analysis, sediment transport dynamics equations will also be applied in the research. Moreover, based on field surveys and field observations and basic monitoring data for hydrological and sediment transport processes and hydrochemical characteristics, the Water- Sediment- Ammonia Nitrogen & Heavy Metals Coupled Model (WSANHMCM) will be established to further study the migration, enrichment and driving mechanism of ammonia nitrogen and heavy metal elements in water bodies. Then by using intelligent computing technology, an ammonia nitrogen concentration prediction model of Taojiang basin based on Gaussian artificial bee colony optimization method will be established. This study will provide technical support for the improvement of water environment and the sustainable utilization of water resources in rare earth mining area combined with source control, process blockade and end treatment, and provide the theoretical basis for water quality prediction, soil erosion control and ecological restoration in the basin.

赣南稀土矿区流域水环境和生态问题已成为近年来科学研究的热点。其地理位置的特殊性和水资源保护的紧迫性，对开展流域水沙过程与氨氮及重金属元素迁移转化机制的研究具有重要的理论和现实意义。. 本项目拟以赣南稀土矿区典型流域—桃江流域为研究对象，以流域水沙过程与氨氮及主要重金属元素迁移富集机理作为研究重点。通过对水文、泥沙输移过程和水化学特征的野外观测和室内分析，采用相关性分析和主成分分析等方法，结合泥沙运动力学方程，构建流域水-沙-氨氮及重金属元素耦合模型，揭示氨氮及重金属元素在水体中的迁移富集及驱动机制；运用智能计算技术，构建基于高斯人工蜂群优化方法的桃江流域氨氮浓度预测模型，从而为实现“源头控制”、“过程阻断”和“末端治理”相结合的稀土矿区水环境改善和水土流失治理的目标提供理论依据和技术支持。

离子型稀土矿开采造成的持续性的水、土等环境问题受到了人们的极大关注。项目选取我国南方典型稀土矿区—桃江流域为研究对象，开展了流域水沙过程与氨氮及重金属时空演化特征及多界面迁移机制研究，结果表明：1）BOD、NH4-N和TP的浓度分别集中在1.8-2.5mg/L、0.12-0.2mg/L和0.02-0.07mg/L；2)桃江流域水质监测结果显示，砷、汞、镉、六价铬、铅、硒、氰化物、铜、锌、阴离子表面活性剂、挥发性酚等11种指标的含量较低或未检出；而溶解氧、高锰酸盐指数、BOD5、氨氮、总磷、氟化物等6项指标含量在流域存在明显的时空分布差异；3）基于BP神经网络模型，利用溶解氧、高锰酸盐指数、BOD5、氨氮、总磷、氟化物等6项水质指标进行桃江水质分类，结果显示流域水质各个监测断面的水质类别以I类、II类和III类为主，水质状况总体上满足该流域的水域功能和保护目标；4）桃江流域沉积物w(Cd)、w(Hg)和w(W)分别超过长江系沉积物背景值2.1-263.2倍、2.7-82.5倍、2.4-30.2倍；w(Zn)、w(Pb)、w(As)、w(Cu)也略超过背景值，w(Cr)未超过背景值；6）水污染成因分析结果表明：桃江流域水质受自然降水和人为污染物排放的共同影响，主要包括各类农业活动中过度施用的农药化肥，以稀土采选为主的各种工业企业排放的废水，以及生活污水和垃圾。研究结果将为赣江上游的水生态保护，尤其是稀土矿区的水环境治理提供资料支撑和科学借鉴。