Fluvial Morphology as a Driver of Lead and Zinc Geochemical Dispersion at a Catchment Scale
Fluvial Morphology as a Driver of Lead and Zinc Geochemical Dispersion at a Catchment Scale
复制标题
河流形态作为流域尺度铅和锌地球化学分散的驱动因素
作者：
P. Onnis;P. Byrne;K. Hudson;T. Stott;C. Hunt
金属开采已造成全球生态系统退化。遗留废物往往集中在监测和研究工作主要集中的前矿山周围。地球化学和物理风化可影响富金属沉积物的位置及其在集水区释放金属的能力。这项研究调查了河流地貌和土壤地球化学驱动锌和铅的分散沿着南Cwmnewdion（威尔士，英国）。对不同地点的沉积物进行了地球化学和矿物学调查（便携式X射线荧光、扫描电子显微镜、X射线衍射和电子探针分析）。在不同的流量，以量化的金属分散在河流中的悬浮泥沙通量估计。地形和坡度分析使我们能够将沉积物侵蚀与源头原生硫化物矿物的暴露联系起来。锌和铅以水相或悬浮沉积物的形式进入溪流。由于地形障碍和河流坡度的降低，次级污染源位于沉积河流区域。沉积物中锌和铅的浓度较低的沉积区，并与铁氧化物或层状硅酸盐。在高流量条件下，河水锌和铅通量突出了它们的流动性。这种多学科方法强调了源头采矿工作对下游集水区的影响，并提供了一种低成本战略，通过地貌观测对沉积物取样。
Metal-mining exploitation has caused ecosystem degradation worldwide. Legacy wastes are often concentrated around former mines where monitoring and research works are mostly focused. Geochemical and physical weathering can affect metal-enriched sediment locations and their capacity to release metals at a catchment scale. This study investigated how fluvial geomorphology and soil geochemistry drive zinc and lead dispersion along the Nant Cwmnewyddion (Wales, UK). Sediments from different locations were sampled for geochemical and mineralogical investigations (portable X-ray fluorescence, scanning electron microscope, X-ray diffraction, and electron microprobe analysis). The suspended sediment fluxes in the streamwater were estimated at different streamflows to quantify the metal dispersion. Topographical and slope analysis allowed us to link sediment erosion with the exposure of primary sulphide minerals in the headwater. Zinc and lead entered the streamwater as aqueous phases or as suspended sediments. Secondary sources were localised in depositional stream areas due to topographical obstruction and a decrease in stream gradient. Sediment zinc and lead concentrations were lower in depositional areas and associated with Fe-oxide or phyllosilicates. Streamwater zinc and lead fluxes highlighted their mobility under high-flow conditions. This multi-disciplinary approach stressed the impact of the headwater mining work on the downstream catchment and provided a low-cost strategy to target sediment sampling via geomorphological observations.
影响因子：
9.8
作者：
Foulds, S. A.;Brewer, P. A.;Rassner, S. M. E.
通讯作者：
Rassner, S. M. E.