黄河包头段柱状沉积物中稀土元素的分布特征

采用室外现场采样及室内分析方法，研究了黄河包头段柱状沉积物中稀土元素的分布特征。结果表明，黄河包头段干流及支流柱状沉积物均以富集轻稀土元素为特征，分布模式的相近以及轻稀土元素的富集共同反映了干流与支流轻稀土元素的继承性和同源性。干流柱状沉积物中轻稀土元素的含量及非稳定态轻稀土元素的形态分布变化趋势均揭示，来自包头市工业废水的外源轻稀土元素对黄河包头段干流的叠加有递减之势。碳酸盐结合态和铁锰氧化物结合态同时是干流和支流柱状沉积物中非稳定态稀土元素的主导形态，干流与支流非稳定态稀土元素形态分布的主要差异表现在支流中稀土元素的可交换态和有机质结合态均明显高于干流。支流柱状沉积物中稀土元素的形态分布及含量仍然表明，其中的稀土，特别是轻稀土元素对黄河包头段干流具有一定的潜在叠加性。

Distribution Characters of Rare Earth Elements (REEs) in Sediment Cores from Baotou Section of the Yellow River

A survey was conducted to reveal rare earth elements (REEs) in sediments from Baotou section of the Yellow River. Our study showed that the region was characterized by a similar distribution pattern and (light rare earth elements) LREE enrichment at either the mainstream or the branches. It has been indicated that the pile- up of external LREEs from industrial wastewater decreased, resulting in tendency of reduction for both LREEs and unstable LREEs elements. The main elements were bond to either carbonates or Fe- Mn oxides in both the mainstream and the branches. However, the difference between them was that the elements bound to organic matter and exchangeable contents in the branches were obviously more than those in the mainstream. And forms and contents of REEs in the branches still showed that there was potential pile- up of REEs, particularly LREEs on the mainstream.