Environment and Climate Change Canada, Water Science and Technology, Aquatic Contaminants Research Division, 105 McGill Street, 7th Floor, Montreal, Quebec H2Y 2E7, Canada.
Environment and Climate Change Canada, Water Science and Technology, Aquatic Contaminants Research Division, 105 McGill Street, 7th Floor, Montreal, Quebec H2Y 2E7, Canada.
Sci Total Environ. 2018 Jan 1;610-611:377-390. doi: 10.1016/j.scitotenv.2017.08.023. Epub 2017 Aug 11.
The Athabasca oil sands deposit is the world's largest known reservoir of crude bitumen and the third-largest proven crude oil reserve. Mining activity is known to release contaminants, including metals, and to potentially impact the aquatic environment. The purpose of this study was to determine the impacts of oil sands mining on water quality and metal bioaccumulation in mussels from the Fort McMurray area in northern Alberta, Canada. The study presents two consecutive years of contrasting mussel exposure conditions (low and high flows). Native freshwater mussels (Pyganodon grandis) were placed in cages and exposed in situ in the Athabasca River for four weeks. Metals and inorganic elements were then analyzed in water and in mussel gills and digestive glands to evaluate bioaccumulation, estimate the bioconcentration factor (BCF), and determine the effects of exposure by measuring stress biomarkers. This study shows a potential environmental risk to aquatic life from metal exposure associated with oil sands development along with the release of wastewater from a municipal treatment plant nearby. Increased bioaccumulation of Be, V, Ni and Pb was observed in mussel digestive glands in the Steepbank River, which flows directly through the oil sands mining area. Increased bioaccumulation of Al, V, Cr, Co, Ni, Mo and Ni was also observed in mussel gills from the Steepbank River. These metals are naturally present in oil sands and generally concentrate and increase with the extraction process. The results also showed different pathways of exposure (particulate or dissolved forms) for V and Ni resulting from different river water flows, distribution coefficient (K) and BCF. Increasing metal exposure downstream of the oil sands mining area had an impact on metallothionein and lipid peroxidation in mussels, posing a potential environmental risk to aquatic life. These results confirm the bioavailability of some metals in mussel tissues associated with detoxification of metals (metallothionein levels), and oxidative stress in mussels located downstream of the oil sands mining area. These results highlight a potential ecotoxicological risk to biota and to the aquatic environment downstream of the oil sands mining area, even at low metal exposure levels.
阿萨巴斯卡油砂矿床是世界上已知最大的稠油储量，也是第三大已探明原油储量。采矿活动会释放出污染物，包括金属，并可能对水生环境造成影响。本研究的目的是确定油砂开采对加拿大阿尔伯塔省北部麦克默里堡地区贻贝水质和金属生物累积的影响。该研究展示了两年连续的贻贝暴露条件（低流量和高流量）。本地淡水贻贝（Pyganodon grandis）被放置在笼子里，并在阿萨巴斯卡河的原位进行了四周的暴露实验。然后分析了水中和贻贝鳃和消化腺中的金属和无机元素，以评估生物累积、估计生物浓缩因子（BCF），并通过测量应激生物标志物来确定暴露的影响。本研究表明，与油砂开发相关的金属暴露以及附近城市处理厂排放的废水对水生生物存在潜在的环境风险。在直接流经油砂开采区的陡岸河中，贻贝消化腺中 Be、V、Ni 和 Pb 的生物累积量增加。陡岸河中贻贝鳃中的 Al、V、Cr、Co、Ni、Mo 和 Ni 生物累积量也增加了。这些金属在油砂中天然存在，通常随着提取过程而浓缩和增加。结果还表明，由于不同的河水流量、分配系数（K）和 BCF，V 和 Ni 的暴露途径（颗粒或溶解形式）不同。油砂开采区下游金属暴露的增加对贻贝的金属硫蛋白和脂质过氧化有影响，对水生生物构成了潜在的环境风险。这些结果证实了与金属解毒（金属硫蛋白水平）和油砂开采区下游贻贝的氧化应激相关的一些金属在贻贝组织中的生物可利用性。这些结果强调了油砂开采区下游生物区系和水生环境的潜在生态毒理学风险，即使在低金属暴露水平下也是如此。
