稀土矿开发排放尾砂中可吸入颗粒物的地球化学特征及环境效应研究

Health, environment are the most pressing problems of atmospheric pollution in rare earth ore area. In the light of the eco-geochemical problem caused by the atmospheric particulate matter in the tailings of rare earth ore, systematic sampling and analysis of inhalable particular matter PM2.5, PM10 and particular matter 2.5-80 μm was performed for in rare earth ore area. Based on a large number of monitoring data and application of comprehensive analysis method, the pollution level and geochemical characteristics of particular matter were investigated. The chemical composition and mineral characteristics of the atmospheric particulate matter in the tailings of rare earth ore was identified. The size distribution of particular matter 2.5-80 μm was investigated. The origin of inhalable particular matter was further analyzed by physical-chemical characteristic, FA and EF analysis and backward trajectory analysis. By using this approach, it was possible to investigate the pollution level, geochemical characteristics of particular matter of the atmospheric particulate matter in the tailings of rare earth ore. This study can only be a small contribution to understanding the influence of developing of rare earth mine on the surrounding environment, which can help explore a long-term mechanism for air quality improvement in rare earth ores and its surrounding areas. All of these findings could provide basic information for controlling the air-borne particulate pollution in the process of developing of rare earth mine.

可吸入颗粒物污染引起的健康、环境问题是稀土矿开发中面临的亟待解决的问题。针对我国稀土矿开发存在的这一生态环境地球化学问题，本次研究对稀土矿尾砂中可吸入大气颗粒物PM2.5、PM10、大气颗粒物2.5-80μm进行了系统采样和分析测试。借助于大量实测数据和综合分析方法的应用，查清稀土矿开发排放尾砂中可吸入颗粒物的污染水平和地球化学特征，开展PM2.5、PM10中无机元素、水溶性离子的变化规律研究，对2.5-80μm大气颗粒物的粒径分布特征进行了探讨。利用因子分析方法、富集因子分析、颗粒物溯源分析技术对颗粒物的来源进行解析。通过研究，可以摸清稀土矿尾砂中可吸入颗粒物的污染水平、地球化学特征，对理解稀土矿开发排放尾砂中可吸入颗粒物的环境效应作出了一点贡献，研究成果可以为探寻稀土矿周边区域空气质量提升方案的制定提供帮助，所有这些研究的结论旨在在为稀土矿开发污染的控制措施的制定提供参考依据。

可吸入颗粒物污染引起的健康、环境问题是稀土矿开发中面临的亟待解决的问题。针对这一生态环境地球化学问题，本次研究对稀土矿开采排放尾砂中可吸入大气颗粒物PM2.5、PM10、大气颗粒物2.5-80μm进行了系统采样和分析测试。借助于大量实测数据和综合分析方法的应用，查清了可吸入颗粒物的污染水平和变化特征，对大气颗粒物的无机元素、稀土元素组成征和矿物学特征进行了研究，对2.5-80μm大气颗粒物的粒径分布特征进行了探讨，利用因子分析方法、富集因子分析法对大气颗粒物的来源进行了解析。通过上述工作得到如下主要结论：（1）稀土矿开采排放尾砂中可吸入颗粒物的质量浓度变化范围较大。研究期间矿区PM2.5质量浓度的平均值为24.05µg·m-3，矿区尾砂堆PM2.5质量浓度的平均值为61.43µg·m-3，非矿区PM2.5质量浓度的平均值为75.45µg·m-3。矿区PM10质量浓度的平均值为41.65µg·m-3。非矿区PM10质量浓度的平均值为85.10µg·m-3。（2）研究区可吸入颗粒物PM10质量浓度季节变化差别不大，夏季PM10的质量浓度最低，为21.94µg·m-³。PM2.5质量浓度季节变化明显，冬季PM2.5质量浓度最高。（3）研究区2.5-80µm的大气颗粒物粒径分布特征比较明显：2.5-5µm>5-10µm>10-20µm>20-40µm>40-80µm。矿区样品较背景区样品在2.5-5µm 范围内矿物质颗粒物（transparent）浓度含量高。（4）矿区可吸入颗粒物中稀土元素总量明显高于非矿区，矿区可吸入颗粒物稀土元素分馏情况相似，均呈现出Eu的负异常，继承了矿区尾砂的特征。（5）因子分析和富集因子分析确定研究区可吸入颗粒物的3种可能来源：1）交通、工业、燃煤等人为因素和与稀土成矿母岩风化有关的土壤颗粒的再悬浮/搬运共同作用的影响；2）土壤尘；3）与采矿活动密切相关的尾砂。通过本次研究，可以摸清稀土矿区大气颗粒物的污染水平、变化规律、地球化学特征及主要来源，对理解稀土矿开采排放的尾砂对可吸入颗粒物的影响作出了一点贡献，研究成果可以为稀土矿开采过程中大气污染的控制措施的制定提供参考依据。