云浮硫铁矿开采对周边表土稀土元素影响研究

摘要

稀土元素(REEs)作为微量元素地球化学行为的示踪剂，能有效反映土壤环境变化。为了评价云浮硫铁矿开采、利用过程中对周边表土 REEs 含量及空间分布的影响，本文采用酸溶法利用 ICP-MS 测定了采自云浮硫铁矿周边57个表土和2个粉尘样品的16种稀土元素含量，并通过统计分析、克里格空间差值和因子分析等法探讨了其可能来源及空间分布的影响因素。结果表明，硫铁矿开采过程中产生的酸性废水和粉尘是影响矿区周边表土稀土元素空间分布的主要因素。轻稀土元素及重稀土元素 Gd 的空间分布特征相似，主要受来自矿区粉尘的影响；重稀土元素(Gd 除外)具有相似的空间分布规律，可能受来自尾矿区酸性废水的影响。Eu*的负异常和Ce*的正异常主要受华南湿热的氧化条件影响，但采矿导致的土壤酸化也是Ce*正异常的重要影响因素；因此，稀土元素对硫铁矿矿区周边土壤环境的变化具有重要的指示意义，且可为污染土壤修复提供指导。%The rare earth elements (REEs), as an indicator for the geochemical behavior of trace elements, can effectively reflect soil environmental changes. In order to investigate the impact of pyrite mining in Yunfu on the surrounding soil environment, the spatial distribution of REEs within top soils around the Yunfu pyrite mining area and its influencing factors are discussed in the present paper. Fifty-seven top soil samples and two dust samples collected from the Yunfu pyrite mining area were investigated for their concentrations of 16 rare earth elements by using the acid leaching method and ICP-MS. The spatial distribution of each element and its influencing factors were analyzed and discussed by using the statistical, Kriging interpolation and factor analysis methods. The results indicated that acid mine drainage and dust generated during the mining process are the main factors influencing the spatial distribution of REEs within top soils. The concentration contours of the LREEs and element Gd are similar and dust generated from the mining area was the main influencing factor for these elements. The concentration contours of the HRREs, except element Gd, were similar and the main influencing factor affecting the spatial distribution of these elements could be the acid mine drainage generated from the tailings and waste-dump area during rain events. Positive abnormality of Ce* and negative abnormality of Eu* are mainly due to warm and humid soil-forming conditions in South China, butsoil acidification caused by pyrite mining is also an important factor for the positive abnormality of Ce*. Therefore, research on REEs in top soils around the mining area is of significance in identifying soil environmental changes and may act as a guideline for contaminated soil remediation.