Environment and Climate Change Canada, 867 Lakeshore Rd., Burlington, Ontario L7R 4A6, Canada.
Environment and Climate Change Canada, University of Victoria, PO Box 3060, STN CSC, Victoria, British Columbia V8W 3R5, Canada.
Sci Total Environ. 2019 Aug 10;677:718-731. doi: 10.1016/j.scitotenv.2019.04.313. Epub 2019 Apr 25.
This paper investigated the sediment/contaminant continuum of bitumen containing sediment, from eroded exposed natural bitumen outcrops to river depositional zone, in order to improve our understanding of the transitional sediment, chemistry and toxicological influence on aquatic health. To achieve this aim, we linked a rainfall simulator with an annular flume to allow for connectivity between terrestrial erosion to stream flow. Bulk sediments were collected from the minable McMurray Formation (MF) on the Ells (EL) and Steepbank (STB) Rivers and from the Clearwater Formation (CF) on the STB. All plots generated similar washoff rates (~25 L hr) and fine eroded sediment (d = 5 μm) regardless of strata. The CF generated the highest total eroded sediment (TES) followed by EL-MF and STB-MF. The STB-MF generated up to three orders of magnitude lower TES than the STB-CF. The EL generated the highest PAH concentrations, however, when normalizing by TES mass delivered to the flume, STB-MF PAH was one to two orders of magnitude higher per unit mass than EL-MF. The TES concentrations were inversely proportional to the degree of bitumen within the sediment (STB-MF > EL-MF > STB-CF). Once the TES was suspended in the flume, there was a change in the dominant PAH for most classes [e.g., Dibenzothiophenes C4 (parent material) to a C3 (TES)]. Further, no flocculation and the buoyant properties of the TES suggested that the sediment and associated PAHs may travel long distances. The EL-MF proved to be the most toxic to fathead minnow embryo survival due principally to the high PAH concentrations and sediment loads. The CF exhibited no toxicological effect. This work has shown the importance of assessing sediment/contaminant characteristics over the continuum (terrestrial erosion/washoff to river deposition) in order to support basin wide management strategies for the protection of aquatic health.
本文研究了含有沥青的沉积物/污染物连续体，从侵蚀暴露的天然沥青露头到河流沉积区，以提高我们对过渡性沉积物、化学物质和对水生健康的毒理学影响的理解。为了实现这一目标，我们将降雨模拟器与环形水槽相连，以实现陆地侵蚀与水流之间的连通性。从 Ells（EL）和 Steepbank（STB）河的可开采 McMurray 组（MF）和 STB 河的 Clearwater 组（CF）收集了大块沉积物。所有的样地都产生了相似的冲刷率（~25L/hr）和细侵蚀沉积物（d=5μm），与地层无关。CF 产生的总侵蚀沉积物（TES）最高，其次是 EL-MF 和 STB-MF。STB-MF 产生的 TES 比 STB-CF 低三个数量级。EL 产生的 PAH 浓度最高，但当将输送到水槽的 TES 质量归一化时，STB-MF 的 PAH 浓度比 EL-MF 高一个到两个数量级。TES 浓度与沉积物中沥青的程度成反比（STB-MF>EL-MF>STB-CF）。一旦 TES 悬浮在水槽中，大多数类别中 PAH 的优势就会发生变化[例如，二苯并噻吩 C4（母体材料）到 C3（TES）]。此外，没有絮凝作用，以及 TES 的浮力特性表明，沉积物和相关的 PAHs 可能会传播很远的距离。EL-MF 对黑头呆鱼胚胎存活率的毒性最大，主要是由于高 PAH 浓度和沉积物负荷。CF 没有表现出毒理学效应。这项工作表明，在整个连续体（陆地侵蚀/冲刷到河流沉积）上评估沉积物/污染物特征的重要性，以支持流域范围内的管理策略，以保护水生健康。
