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The anthropogenic contribution of trace metals to settling particulate matter (SPM) and surficial sediments was determined on the high-energy continental shelf adjacent to Sydney, Australia. Settling particulate matter and surficial sediment was collected in the vicinity of a major sewage outfall and at five control sites on the middle shelf (80-100 m water depth). Sediment traps were deployed on 10 occasions for up to 2 weeks during the summer and winter of 1995 and SPM was analyzed for Ag, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn. Cobalt, Fe, Mn and Ni act conservatively in SPM and in sediments regionally and are used as normalizing elements to determine anthropogenic enrichment. Surficial sediments and SPM are enriched in Ag, Cr, Cu, Pb and Zn near a major ocean outfall and at four of the five control sites, although sewage particles contribute < 5% of trace metals in the total sample. Silver is the most sensitive trace metal tracer for establishing the presence of sewage particulate matter. Sewage particulate matter flux near the outfall was estimated using a two end-member mixing model and is below 0.5 g m(-2) day(-1) during all deployment periods. The mean sewage particulate matter flux at sampling locations 30 km and 60 km north of the outfall are <0.13 g m(-2) day(-1) and <0.01 g m(-2) day(-1), respectively, indicating an efficient dispersal of anthropogenic material on this high energy continental shelf. 相似文献
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由于向下伏或周围地下水体系渗漏造成的损失，地形封闭的盆地可能在水文上是开放的。在这种情况下，这些渗漏损失对盆地内形成的蒸发盐矿物的矿物和厚度可能起了相当大的控制作用。在确定蒸发盐矿床的厚度和矿物特征的过程中，水文上开放的盆地中的地下水流出量与流入量之比（流量比）象流入水的溶质组分一样重要。当达到稳态流量比时，就会形成由两，三种矿物组成的巨厚层，而不是形成由多种矿物祝得克萨斯州和新墨哥州南部高原的一 相似文献
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