Investigating the toxicity, microbial response and biogeochemical composition of gamma irradiated end products in oil sands process material

艾伯塔省东北部的油砂储量是世界上最大的石油储量之一，估计有2.5万亿桶可采沥青存在于由沙、粘土和水组成的矿物基质中。从挖掘出的油砂中提取沥青的传统方法包括使用热水消化和浮选，产生由水、砂、细粉、残留沥青和石脑油产品组成的细尾矿浆，其中包括一种被称为流体细尾矿(FFT)和油砂工艺水(OSPW)的材料。环烷酸(NA)是大多数石油的组成成分，包括在阿萨巴斯卡油砂中发现的那些。它们在环境中的存在可能会造成严重的问题，因为新释放的NAS对水生生物是有毒的。尽管在环境中的毒性会随着时间的推移而降低，但NA混合物中的难降解成分可以持续数年。石油公司感兴趣的是找到一种最佳解决方案来处理快速傅里叶变换，减少和消除残留的NAS，以便它可以安全地释放到自然环境中，并符合监管指南。我们的研究项目是研究高能伽马辐射去除和降低NA混合物毒性的效果。初步的实验室规模试验记录了在OSPW中NAS减少了95%，在FFT中减少了50%。这项研究计划将确认伽马辐照在OSPW和FFT中分解NA混合物的有效性，在实验室评估对辐照材料的生物反应，并使用野外电池在自然环境中监测伽马处理的长期特征。以对环境负责的方式处置油砂加工废物，对于确保积极主动的区域环境管理至关重要，该管理应针对该区域的累积生物物理、健康和长期管理战略。这项研究产生的结果将有助于油砂运营商更好地了解废物处理，并为环境敏感区域的可持续管理实践提供潜在的处理解决方案。

The oil sands deposits of north-eastern Alberta are one of the largest oil reserves in the world, containing an estimated 2.5 trillion barrels of recoverable bitumen held in a mineral matrix consisting of sand, clay and water. Traditional methods used to extract bitumen from excavated oil sands involve the use of hot water digestion and flotation which produces a fine tailing slurry consisting of water, sand, fines, residual bitumen and naphtha products comprising a material known as fluid fine tails (FFT) and oil sands process water (OSPW). Naphthenic acids (NA) are components of most petroleum, including those found in the Athabasca oil sands. Their presence in the environment can pose significant problems since freshly released NAs are toxic to aquatic organisms. Although toxicity declines with time in the environment, the refractory components of the NA mixture can persist for years. The oil companies are interested in finding an optimal solution to treat FFT and reduce and remove residual NAs so that it can be safely released into the natural environment and comply with regulatory guidelines. Our research program is investigating the effects of high energy gamma irradiation to remove and reduce the toxicity of NA mixtures. Preliminary bench scale trials have documented 95% reduction of NAs in OSPW and 50% reduction in the FFT. This research program will confirm the efficacy of gamma irradiation in breaking down NA mixtures in OSPW and FFT, assess biological responses to the irradiated materials in the laboratory, and use field cells to monitor the longer-term characteristics of the gamma treatments in a natural environment. Disposal of the oil sands process waste in an environmentally responsible fashion is paramount to ensuring proactive regional environment management that addresses the cumulative biophysical, health and long-term management strategy for the region. The outcomes generated by this research will contribute to an improved understanding of waste treatment for oil sands operators and provide potential treatment solutions for sustainable management practice in an environmentally sensitive region into perpetuity.