Analytical, Environmental and Geo-Chemistry Department (AMGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
LASIR CNRS UMR 8516, Universite de Lille, Cite Scientifique, 59655 Villeneuve d'Ascq Cedex, France.
Environ Sci Technol. 2020 Dec 1;54(23):15151-15161. doi: 10.1021/acs.est.0c05954. Epub 2020 Nov 10.
Different mobilization mechanisms control the metal distribution in surface sediments of the Belgium coastal zone (BCZ) and the anoxic Gotland basin (GB). This mobilization was studied using DGT (diffusive gradients in thin films): vertical one-dimensional (1D) profiles of Cd, Co, Cu, Fe, Mn, Ni, Pb, and Zn were measured at 5 mm intervals, while two-dimensional (2D) high-resolution (100 μm) images of smaller zones of the sediment profile were obtained on separate DGT probes. Removal of dissolved Cd, Cu, and Pb in BCZ sediments caused steep vertical gradients at the sediment-water interface that were well replicated in 1D profiles and 2D images. While 1D profiles showed apparent coincident maxima of Co, Mn, and Fe, 2D images revealed mutually exclusive Co and Fe mobilization. Correlation analysis supported this observation and showed a consistent linkage between Co and Mn. Sharp maxima of some metals in the vertical 1D profiles of GB sediment were attributed to localized mobilization in microniches. Examination of an ∼1 mm diameter Cu and Ni maximum in 2D, defined by ∼300 data points, showed that the metals were supplied from localized decomposition of reactive organic material, rather than from reductively dissolving Fe or Mn oxides, and that they were removed as their sulfides.
不同的迁移机制控制着比利时沿海带（BCZ）和缺氧的哥特兰盆地（GB）表层沉积物中的金属分布。这项迁移机制的研究采用了 DGT（薄膜扩散梯度技术）进行：在 5 毫米的间隔处测量了 Cd、Co、Cu、Fe、Mn、Ni、Pb 和 Zn 的垂直一维（1D）剖面，同时在单独的 DGT 探针上获得了沉积物剖面较小区域的二维（2D）高分辨率（100μm）图像。BCZ 沉积物中溶解态 Cd、Cu 和 Pb 的去除导致了在沉积物-水界面处形成陡峭的垂直梯度，这在 1D 剖面和 2D 图像中得到了很好的重现。虽然 1D 剖面显示出 Co、Mn 和 Fe 的明显一致的最大值，但 2D 图像揭示了 Co 和 Fe 的相互排斥的迁移。相关性分析支持了这一观察结果，并显示 Co 和 Mn 之间存在一致的联系。GB 沉积物垂直 1D 剖面中一些金属的急剧最大值归因于微生境中局部的迁移。对 2D 中约 1 毫米直径的 Cu 和 Ni 最大值（由约 300 个数据点定义）的检查表明，这些金属是由反应性有机物质的局部分解提供的，而不是来自还原溶解的 Fe 或 Mn 氧化物，并且它们被作为硫化物去除。
