淮南采煤沉陷区表层沉积物稀土元素地球化学特征

Geochemical characteristics of rare earth elements in surface sediments from Huainan coal mining subsidence area,Anhui Province,China

稀土元素由于其独特的化学特征被广泛应用于环境地球化学分析过程研究。以淮南采煤沉陷区表层沉积物中稀土元素(REEs)为研究对象,采集研究区潘一、顾桥、谢桥沉陷区的表层沉积物样品共12个,采用ICP-MS对样品的稀土元素含量进行测试分析,探讨了表层沉积物中稀土元素的含量分布特征、控制因素及其物质来源。结果表明:研究区表层沉积物中稀土元素含量为54.63~130.45μg/g,平均102.60μg/g;LREE/HREE比值为11.89~20.55,平均14.29,轻稀土呈现明显富集现象;相关性分析结果显示,REEs趋向于黏土组分中富集;研究区养殖和捕捞活动导致表层沉积物中稀土元素含量的降低;球粒陨石标准化结果表明,研究区稀土元素呈现不同程度的La和Gd正异常,其中,Gd正异常主要是受到燃煤的影响,而La正异常主要与燃煤和化肥有关。结合Pearson相关性、球粒陨石标准化和(La/Yb)_(N)-(La/Sm)_(N)-(Gd/Yb)_(N)三元图判别,认为研究区水体表层沉积物中稀土元素与人类活动(燃煤和化肥)有关,研究认识为污染物的源头控制和煤矿区环境的生态治理提供参考依据。

Rare earth elements(REEs)are widely used in environmental geochemical analysis process research due to their unique chemical characteristics.This study investigated the geochemical characteristics of rare earth elements in surface sediment from the Huainan coal mining subsidence area,Anhui Province,China.Twelve surface sediment samples were collected from Panyi,Guqiao and Xieqiao subsidence areas in the study area.The content of rare earth elements in the samples was tested and analyzed by ICP-MS,and the distribution characteristics and controlling factors of REEs and its material sources were discussed.The results show that the rare earth element content in the surface sediments is 54.63-130.45μg/g,with an average of 102.6μg/g.The ratio of LREE/HREE varies from 11.89 to 20.55,with an average value of 14.29.The enrichment of LREE is obvious in the surface sediments.Correlation analysis results show that REEs tend to be concentrated in clay components;the intensive artificial breeding and fishing activities in this area lead to the reduction in the content of REEs in the surface sediment;the chondrites-normalized REEs distribution pattern show different degrees of positive La and Gd anomalies;the positive Gd anomalies are influenced mainly by coal combustion,while the La anomalies are mainly related to the contribution of coal and fertilizer.Through the combination of Pearson correlation,chondrite standardization,and(La/Yb)_(N)-(La/Sm)_(N)-(Gd/Yb)_(N) ternary diagram,it is concluded that the REEs in the surface sediments of the study area are related to human activities(coal burning and chemical fertilizers).The study provides a reference basis for the source control of pollutants and the ecological treatment of coal mine environment.