Geochemical character of rare earth elements in Longgan lake,East of China

The rare earth elements(REEs)in Longgan lake is studied by the solvent extraction or sequential extraction procedure and the Inductively coupled plasma mass spectrometry(ICP-MS)determination. The contents of the dissolved REEs in the lake vary widely from 35.14 to 129.81 ng/kg. The dissolved REEs have a flat shale-normalized pattern,this is because the dissolved REEs are mainly presence in the fine colloidal phase(as a result of 0.22μm filtration)in a macrophyte lake. The amount of REEs in the sequential extracted four fractions obeys the following order:residual>bound Fe-Mn oxides>>adsorbed-exchangeable-carbonate(AEC)or bound organic matter. The partitioning characteristics of REEs in the suspended matter are quite similar,with the main amount in residual forms. The normalized patterns of REEs in AEC,bound organic matter and Fe-Mn oxides are same,with middle REEs enrichment,but the residual forms have a flat pattern. The middle REEs are more difficult to be transferred than other REEs in the water of Longgan lake,but these have more potential activities.