Que Wenpiao, Yi Liwen, Wu Yueting, Li Qiuping
College of Geographical Sciences, Hunan Normal University, Changsha, 410081, China.
Hunan Normal University Key Laboratory of Geospatial Big Data, Changsha, 410081, China.
Sci Rep. 2024 Sep 2;14(1):20318. doi: 10.1038/s41598-024-71502-3.
Heavy metals mainly exist on the surface of sediment particles and are transported using particulate matter as carriers. Therefore, the particle size of sediment particles can affect the adsorption, release, and migration of heavy metals. This study aim to investigate the distribution characteristics and chemical fraction of Cd, Pb, and As contents in sediments of different particle sizes using the BCR method, and to determine the key factors affecting the distribution of heavy metals through mineralogical methods such as XRD and EDS. The results revealed that the overall content of various forms of heavy metals increases with the decrease of particle size, mainly presents in fine particles. The mineralogical analysis results indicated that fine particles predominantly contained clay minerals such as chlorite and illite and coarse particles mainly include primary minerals. Due to the mining areas in the middle-upstream, Cd, Pb and As were primarily associated with galena, sphalerite and pyrite, respectively. The distribution of heavy metals is jointly influenced by sediment particle size and sediment material composition.
重金属主要存在于沉积物颗粒表面，并以颗粒物为载体进行迁移。因此，沉积物颗粒的粒径会影响重金属的吸附、释放和迁移。本研究旨在采用BCR法研究不同粒径沉积物中镉、铅和砷含量的分布特征及化学形态，并通过XRD和EDS等矿物学方法确定影响重金属分布的关键因素。结果表明，各种形态重金属的总含量随粒径减小而增加，主要存在于细颗粒中。矿物学分析结果表明，细颗粒主要含有绿泥石和伊利石等粘土矿物，粗颗粒主要包括原生矿物。由于中上游地区的矿区，镉、铅和砷分别主要与方铅矿、闪锌矿和黄铁矿有关。重金属的分布受沉积物粒径和沉积物物质组成的共同影响。
