XIE Wen1,2 , XU Zhi-fang 3,*, LIU Congqiang 1
(1. State Key Laboratory of Environmental Geochemistry , Institute of Geochemistry , Chinese Academy of Sciences , Guiyang 550002 , China ;
2. The Graduate University of Chinese Academy of Sciences , Beijing 100049 , China ;
3. Key Laboratory of Engineering Geomechanics , Institute of Geology and Geophysics , Chinese Academy of Sciences , Beijing 100029 , China )
Abstract: The rare-earth elements (REEs) of suspended particulate matter (SPM) in the upper reaches of the Xijiang River were measured by inductively coupled plasma mass spectrometry (ICP-MS) after improving the BCR sequential extraction method. The result showed that the total REE concentrations of SPM are obviously higher than those of dissolved load, ranging from 188～402 mg/kg. The PAAS-normalized REE patterns for the three unstable fractions of REEs (AEC, bound to Fe-Mn oxides, bound to organic matter) exhibit middle REE (MREE) enrichment, indicating the preferential weathering of phosphatic minerals. The stable fraction of REEs (residual) presents a flat PAAS-normalized REE pattern, indicating no significant fractionation of REE in residual form. The percentage of four fractions of SPM obeys the following order: residual＞bound to organic matter, bound to Fe-Mn oxides ＞AEC. The MREEs (Sm, Eu, Gd) have relatively lower percentages in the residual fraction and higher in other three unstable fractions.
Key words: the upper reaches of the Xijiang River; rare-earth elements (REEs); suspended particulate matter (SPM)
EARTH AND ENVIRONMENT Vol. 38, No.4, Tot No.282, 2010, Page 414-420
