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首页> 外文期刊>Integrated Environmental Assessment and Management >Background Levels of Metals in St. Lawrence River Sediments: Implications for Sediment Quality Criteria and Environmental Management
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Background Levels of Metals in St. Lawrence River Sediments: Implications for Sediment Quality Criteria and Environmental Management

机译：圣劳伦斯河沉积物中金属的背景水平：对沉积物质量标准和环境管理的启示

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摘要

Preindustrial sediments dredged from the St. Lawrence Seaway are often considered potentially toxic relative to interim sediment quality criteria. The aim of the present study was to better document the background levels of target metals that were once used to define the minimal threshold of these criteria. Three extractions were performed on sediment samples to evaluate the distribution and potential bioavailability of trace metals. The results showed that the background levels established for the criteria are representative of contaminant concentrations observed in preindustrial sediments but not of the postglacial marine clays underlying these sediments. Chromium, nickel, and copper concentrations in postglacial marine clays, when solubilized by strong acids, exceeded the minimal effect threshold, whereas chromium and nickel frequently exceeded the toxic effect threshold and therefore are problematic in terms of applying sediment quality assessment criteria. The results suggest that these trace metals are mostly associated with inert silicates in postglacial marine clays and are unlikely to be bioavailable to aquatic organisms. Postglacial marine clays should be better considered differently than are sediments in regard to the sediment quality criteria implementation. Accordingly, the use of tools to identify the postglacial material may become necessary if a particular management disposition should be established for this sedimentary material. Total recoverable aluminum concentrations in sediments, in conjunction with other physical characteristics, was shown to be an interesting tool to identify this specific material. The normalization of metals concentrations with total recoverable aluminum concentrations would take account of natural mineralogical and textural variability of freshwater sediments in the quality assessment process.
机译：从圣劳伦斯海道疏dr的工业化前沉积物相对于临时沉积物质量标准通常被认为具有潜在毒性。本研究的目的是更好地记录目标金属的背景水平，这些水平曾经被用来定义这些标准的最小阈值。对沉积物样品进行了三次萃取，以评估痕量金属的分布和潜在的生物利用度。结果表明，为该标准确定的背景水平代表了工业化前沉积物中观察到的污染物浓度，但并不代表这些沉积物下方的冰川后海洋粘土。冰川后海洋粘土中的铬，镍和铜浓度在被强酸溶解后超过了最小作用阈值，而铬和镍经常超过了毒性作用阈值，因此在应用沉积物质量评估标准方面存在问题。结果表明，这些痕量金属主要与冰川后海洋粘土中的惰性硅酸盐有关，不太可能被水生生物利用。在沉积物质量标准的实施方面，应更好地考虑冰川后海洋粘土与沉积物的区别。因此，如果应该为这种沉积物建立特殊的管理处置方式，则有必要使用工具来识别冰川后物质。沉积物中可回收的总铝浓度与其他物理特征一起被证明是识别这种特定材料的有趣工具。用总可回收铝浓度对金属浓度进行归一化将考虑质量评估过程中淡水沉积物的自然矿物学和质地变化。

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