环境地球化学国家重点实验室知识库

Purpose The purposes of this paper are to investigate the geochemical characteristics of rare earth elements (REEs) in the surface sediments of Jiulong River, southeast China, to probe the provenance compositions of the sediments, and to analyze the potential anthropogenic influence on REEs in the sediments. REEs and Sr-Nd isotopes were selected as the tools because REEs can be used to identify the anthropogenic effects on sediments and Sr-Nd isotopes have been widely known as powerful tracers for provenance analysis. Materials and methods Fifty-three samples of surface sediments (0~5 cm) were collected from Jiulong River. The concentrations of REEs and Sr-Nd isotopic compositions in the surface sediments were determined by inductively coupled plasma mass spectrometry (ICP-MS) and thermal ionization mass spectrometry (TIMS), respectively. The chondrite-normalized and WRAS-normalized REEs patterns, enrichment factor, plots of La-Th-Sc and La/Yb-∑REE, and plots of εNd(0) vs 87Sr/86Sr and εNd(0) vs δEu are presented. Results and discussion The mean concentration of ΣREEs in the surface sediments of Jiulong River was 254.25 mg kg−1 . The mean values of ΣLREEs (227.6 mg kg−1 ), ΣHREEs (26.64 mg kg−1 ), and (La/Yb)N ratios (9.24) suggested an enrichment of LREEs compared to HREEs. Negative Eu anomalies were observed in the surface sediments. The distribution patterns of REEs in the surface sediments from different areas of Jiulong River were remarkably similar. The values of 87Sr/86Sr, 143Nd/144Nd, and εNd(0) were 0.714091~0.733476, 0.511875~0.512271, and − 14.88~− 7.16, respectively. The plots of εNd(0) vs 87Sr/86Sr, εNd(0) vs 1/[Nd], and εNd(0) vs δEu indicated that the sediments in Jiulong River were mainly derived from natural geological processes and the REEs might be also influenced by anthropogenic activities such as Fujian Pb-Zn deposit, coal ash, and industrial sludge. Conclusions The REEs in the surface sediments at different sites are similar in geochemical characteristics, with a rightinclined distribution pattern and higher enrichment of light REEs (LREEs) compared to heavy REEs (HREEs), and a negative Eu anomaly but no evidence of Ce anomaly. The sediments in Jiulong River were mainly derived from natural geological processes (granite and magmatic rocks), and the REEs in the sediments were also influenced by anthropogenic activities (Fujian Pb-Zn deposit, coal ash, and industrial sludge).