Environment and Climate Change Canada, Burlington, Ontario, Canada.
Environment and Climate Change Canada, Victoria, British Columbia, Canada.
Sci Total Environ. 2018 Jun 1;626:1382-1393. doi: 10.1016/j.scitotenv.2018.01.105. Epub 2018 Feb 19.
Bitumen-bearing suspended sediment (SS) eroded from the McMurray Formation (MF) are fine grained (silts and clays) and coated with natural hydrophobic oils. This results in poor settling and long range transport of associated contaminants. There was a longitudinal increase in polycyclic aromatic compound (PAC) concentrations for rivers that erode the MF from upstream to downstream regardless of time-of-year, while loads were substantially increased during high flow periods when the erosive forces are the greatest and the overland flow contribution is high. Within the MF, variation in PAC contributions is seen by the Ells River having higher loads than the Steepbank River. Using the Ells and Steepbank as examples, double plot PACs ratios suggest that the PAC concentrations and signatures vary spatially within the MF but that the weathering processes may be the same. Plots of the various homologs of PACs generally illustrated a normal distribution which suggests petrogenic origins. However, several PAC ratios suggested that both the parent material and the SS are pyrogenic in nature. While it is likely that some level of atmospheric deposition (anthropogenic or from forest fire) is incorporated into the SS of the rivers, it is likely to be limited relative to the proportion of naturally eroded MF sediments. Additional analysis will be needed to distinguish the relative risk of both anthropogenic (e.g., industrial operations) and natural sources (bitumen deposits, forest fire) of PACs to the SS and to long-range depositional environments, as they may have potential aquatic ecological effects.
从麦克默里堡组（MF）侵蚀出来的含沥青悬浮泥沙（SS）是细颗粒的（粉砂和粘土），并覆盖有天然疏油物质。这导致污染物的沉降不良和长距离迁移。从上游到下游侵蚀 MF 的河流的多环芳烃化合物（PAC）浓度呈纵向增加，无论一年中的哪个时候都是如此，而在高流量时期，侵蚀力最大且地表径流贡献高时，负荷会大大增加。在 MF 内部，埃尔斯河的 PAC 负荷高于陡岸河，这表明 PAC 的贡献存在差异。以埃尔斯河和陡岸河为例，双比 PACs 比值表明，PAC 浓度和特征在 MF 内存在空间差异，但风化过程可能相同。PAC 各种同系物的图通常表明呈正态分布，这表明其具有生源起源。然而，有几个 PAC 比值表明，母体材料和 SS 均具有源自热解的性质。尽管大气沉降（人为或森林火灾）可能会在一定程度上进入河流的 SS，但与自然侵蚀的 MF 沉积物的比例相比，可能是有限的。需要进一步的分析来区分 SS 和长距离沉积环境中 PACs 的人为（例如工业作业）和自然来源（沥青矿床、森林火灾）的相对风险，因为它们可能对水生生态系统具有潜在影响。
