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

阿尔伯塔东北部的油砂矿床是世界上最大的石油储量之一，估计含有2.5万亿桶可开采的沥青，这些沥青保存在由沙子、粘土和水组成的矿物基质中。用于从挖掘的油砂中提取沥青的传统方法涉及使用热水消化和浮选，其产生由水、砂、细粒、残余沥青和石脑油产物组成的细粒尾矿浆料，所述石脑油产物包含称为流体细粒尾矿（FFT）的材料和油砂工艺水（OSPW）。环烷酸（NA）是大多数石油的组成部分，包括阿萨巴斯卡油砂中发现的那些。它们在环境中的存在会造成严重的问题，因为新释放的NA对水生生物有毒。虽然毒性在环境中随着时间的推移而下降，但NA混合物的难降解成分可以持续多年。 石油公司有兴趣找到一种最佳的解决方案来处理FFT，减少和去除残留的NA，使其能够安全地释放到自然环境中，并符合监管指南。 我们的研究计划是调查的影响，高能量伽马辐照，以消除和减少NA混合物的毒性。初步的实验室规模试验已经记录了OSPW中NAs减少95%，FFT减少50%。该研究计划将确认伽马辐照在OSPW和FFT中分解NA混合物的功效，评估实验室中辐照材料的生物反应，并使用现场细胞监测自然环境中伽马处理的长期特性。以对环境负责的方式处置油砂加工废物对于确保积极的区域环境管理至关重要，该管理涉及该区域的累积生物物理、健康和长期管理战略。这项研究产生的成果将有助于提高对油砂运营商废物处理的理解，并为环境敏感地区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.