Key laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, People's Republic of China.
Environ Monit Assess. 2012 Dec;184(12):7275-92. doi: 10.1007/s10661-011-2496-6. Epub 2012 Jan 19.
Surface sediment samples were collected at 27 stations of Bohai Bay, North China. Sequential extractions were carried out in this study. REE were leached out from four labile fractions: Exchangeable (L1), bound to carbonates (L2), bound to Fe-Mn oxides (L3), bound to organic matter (L4), and the remainder was residual (R5). The total contents of REE fluctuate slightly in Bohai Bay, and are mainly concentrated in the middle region, showing relatively higher levels in the north than that in the south of Bohai Bay. Percentages of L1, L2, L3, L4, and R5 for REE suggest that the residual fraction accounts for the major component of REE, whereas Fe-Mn oxides also play important roles in combining labile REE. As the REE complex is not stabilized, the competition of complex could induce dissociation of the complex and redistribution of the REE in various environments. According to REE patterns and Y/Ho ratios of samples, REE are not anthropogenic or oceanic sources but riverine input, whereas suitable environment varieties can slightly affect the patterns and fractionations of REE. As powerful tracers for the variable of environment, higher anomaly of Eu and Ce in southern regions indicates a greater reduction in the condition of surface sediment in the south than that in the north of Bohai Bay.
本研究对渤海湾 27 个站位的表层沉积物样品进行了连续提取，分析了其中的稀土元素（REE）赋存形态。提取过程中，将 REE 从四个易提取的部分（L1、L2、L3 和 L4）和剩余的稳定部分（R5）中分离出来。渤海湾的 REE 总含量波动较小，主要集中在中部地区，北部的 REE 含量略高于南部。L1、L2、L3、L4 和 R5 等部分的 REE 百分比表明，稳定的残余部分是 REE 的主要组成部分，而铁锰氧化物也在结合易提取的 REE 方面发挥了重要作用。由于 REE 配合物不稳定，配合物的竞争可能导致配合物的解离和 REE 在各种环境中的重新分配。根据样品的 REE 模式和 Y/Ho 比值，REE 不是人为或海洋来源，而是河流输入，而合适的环境变化可以轻微影响 REE 的模式和分馏。作为环境变化的有力示踪剂，南部地区 Eu 和 Ce 的高异常表明，与北部相比，南部表层沉积物的还原条件更为严重。
