扬州古运河沉积物中稀土元素形态分布特征

摘要

采用ICP-MS和BCR连续提取法检测了扬州古运河三湾段沉积物中稀土元素含量和形态分布,并与参考值(中国东部上地壳、江苏省表层A层土壤、黄河沉积物和长江沉积物)稀土元素含量进行对比,研究了稀土元素的富集与亏损状况、不同赋存形态的分布特征及沉积物中稀土元素物质来源.研究结果表明:样品中稀土元素Ce、Pr、Nd、Sm四种稀土元素的含量分别高于四个参考值,其中以Ce的超标较为严重.沉积物中轻稀土元素存在一定的富集现象,异常系数δEu值达1.2.Gd的[(F1+F2+F3)/T)]值均高于其它元素,导致Gd元素由沉积物中向上覆水体迁移能力较强,潜在生态危害性较大.物源指示分析,扬州古运河三湾段沉积物中的稀土元素物质来源与黄河沉积物相似.%The contents and speciation distributions of rare earth elements(REEs) in the sediment from Sanwan section of Yang-Zhou ancient canal were determined by the methods of ICP-MS and BCR sequential extraction method,and the determined results were compared with the REEs reference contents (background values of REEs in the upper crust of Eastern China,A layer soil of Jiangsu province,the Yellow River sediments and Yangtze River sediments).The enrichment and loss of rare earth elements,distribution characteristics of four speciations and the source of REEs in sediment were studied. The results showed that the contents of four kinds of rare earth elements including Ce,Pr,Nd and Sm were higher than four reference values,particularly Ce among which was exceeding the standard more seriously. There was a certain enrichment of light rare earth elements in sediment,the abnormal coefficient value of Ce was 1.2. The value of [(F1+F2+F3)/T)] of Gd was higher than other rare earth elements, which caused that the migration of Gd from sediment to overlying water was highly strong,and the potential ecological risk was more significant. Source indication analysis indicated that the source of REEs in Sanwan section sediment of Yangzhou ancient canal was similar to that in Yellow River sediments.