Distribution of Rare Earth Elementsin the Soft Tissue of Hyriopsis cumingii and the Correlation with Metal Speciation of Sediments in Poyang Lake

XU Xuming1, PAN Baozhu2, SHU Fengyue3, CHEN Xiufen1, NI Jinren1,4,†

1. School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055; 2. Institute of Water Resoures and Hydro-electric Engineering, Xi’an University of Technology, Xi’an 710048; 3. College of Life Sciences, Qufu Normal University, Qufu 273165; 4. Key Laboratory of Water and Sediment Sciences (MOE), Department of Environmental Engineering, College of Environmental Sciences and Engineering, Peking University, Beijing 100871; † Corresponding author, E-mail: nijinren@iee.pku.edu.cn

Abstract Hyriopsis cumingii and corresponding sediment in five respective monitoring sections of Poyang Lake were sampled in autumn 2014, followed by the detection of rare earth elements (REES) in the soft tissue of Hyriopsis cumingii and sediments treated by BCR sequential exaction. As results, the mean value of total REES in the soft tissue of Hyriopsis cumingii was 15.52 mg/kg, and light REES were more easily accumulated, indicating that the biological effect of light REES on Hyriopsis cumingii was stronger than heavy REES. Correspondingly, the mean value of total REES in sediments was 285.22 mg/kg with higher light REES, suggesting the strong terrigenous properties. The REES concentration in the sediment treated by BCR sequential extraction ranked as: residual fraction>reducible fraction>oxidizable fraction>exchangeable fraction. The exchangeable fraction displayed the lowest REES concentration but the largest difference in spatial distribution; however, they were all under low risk level analyzed by Risk Assessment Code. Significant and positive correlations can be observed between REES in Hyriopsis cumingii and that in the oxidizable fraction of sediments, suggesting that the bioavailability of REES would mainly depend on REES bound to organic matter. Key words rare earth elements; Hyriopsis cumingii; sediments; Poyang Lake; correlation