Reading the molecular fine print: Ultrahigh resolution mass spectrometry and the environmental impact of the Athabasca oil sands industry

Overview:
The oil sands industry in Alberta, Canada, represents an alternative source of petroleum which has positioned Canada as the leading supplier of oil to the USA. The oil sands material consist of clay, sand, water, and bitumen, where the bitumen can be extracted using an alkaline hot water extractions process. Approximately three barrels of water are needed to produce one barrel of oil but this water, oil sands process affected water (OSPW), cannot be discharged back into the environment, due to federal regulations. As a result, the OSPW is stored in vast tailings ponds, currently estimated to hold approximately 1 trillion litres of water. The vast amounts of tailings pond waters contain substances that are known to be toxic to aquatic environments. For example, recent studies have implicated a wide range of classical naphthenic acids as principal toxicants, along with heavy metals and salts. The anthropogenic impact of future release of OSPW upon the aquatic environment is thus of increasing concern. There is a strong need for improved methodologies for characterization of the oil sands naphthenic acids for environmental monitoring, particularly with respect to understanding the chemistry of highly complex environmental samples. The comprehensive characterization of the organic fraction of OSPW with regards to fate and transport in aquatic environments is not yet established. Ultrahigh resolution mass spectrometry, particularly Fourier transform ion cyclotron resonance (FTICR) mass spectrometry (MS), has played a key role in the molecular characterization of environmental samples, leading to complex data sets which subsequently serve as "profiles" or "fingerprints" of the organic components in OSPW. The proposed work will, for the first time, utilize advances in proprietary software tools, developed at the University of Warwick, to improve and expand the molecular characterization of principal toxic components in OSPW, including providing greater insight into isomeric structures.

Methodology:
This study will fingerprint oil sands processed waters collected from the Athabasca oil sands region, along with groundwater overlying undeveloped shale gas and tight oil reservoirs in Canada. A better understanding of the influence of environmental processes upon the molecular profiles is required, as it can be used to build a model of the environmental fate of oil sands components. In order to address this, the transport of oil sands components through soil and their subsequent microbial degradation will be experimentally investigated in the laboratory. The resulting samples will be characterized using ultrahigh resolution mass spectrometry; one of the smallest mass differences commonly observed in the mass spectra of naphthenic acid mixtures is 3.4 mDa, resulting from the complex mixture rich in Ox and SOx isobars. The project will also refine the interpretation and comparison of MS data to better characterize naphthenic acids in aquatic environments.