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The processing of bitumen in the Athabasca oil sands region (AOSR) produces extensive volumes of oil sands process-affected water (OSPW) and tailings, which are stored within tailings ponds and settling basins to promote the consolidation of solids and the recycling of water. Oil sands operators are actively investigating dry and wet reclamation strategies in order to reduce their inventory of tailings and return disturbed land back to its original state. An important component of the reclamation of tailings is understanding the environmental fate of naphthenic acids (NAs), which are considered the most toxic constituents of OSPW and tailings. However, since NAs exist as a complex mixture comprised of thousands of compounds from dozens of chemical classes, the characterization of NAs within environmental samples poses significant challenges to analytical chemists. This dissertation is focused on the characterization of naphthenic acids by comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GC×GC/MS). GC×GC/MS offers unparalleled chromatographic separation and peak capacity and has been used in recent years to resolve individual constituents within complex mixtures, including structural isomers. Since the biodegradation and toxicity of NAs is structure-specific and can vary between structural isomers, the profiling of individual NAs by GC×GC/MS is expected to enhance the monitoring of NAs within environmental samples impacted by oil sands activity. In this thesis, GC×GC coupled with time-of-flight mass spectrometry (TOFMS) was used to structurally elucidate a number of ‘unknown’ classical and sulfur-containing naphthenic acids by interpretation of their electron ionization (EI) mass spectra and, if available, confirmed by comparison with the spectra of references standards. GC×GC/TOFMS was also utilized as a fingerprinting tool to assess the temporal and spatial variability at two reclamation sites in the AOSR: Syncrude’s Sandhill Fen reclamation site and Base Mine Lake. Lastly, a methodology was developed which coupled GC×GC with a high resolution quadrupole time-of-flight mass spectrometer (QTOFMS) for the improved profiling of NAs. GC×GC/QTOFMS is advantageous for the monitoring of NAs since it can provide useful fingerprints via isomer distributions, differentiate NAs from several chemical classes, and provide a global overview of the elemental compositions (assigned by mass accuracy) within NA mixtures. / Thesis / Doctor of Philosophy (PhD)

Made available in DSpace on 2016-12-23T14:41:52Z (GMT). No. of bitstreams: 1 Thieres Magaive Costa Pereira.pdf: 7173330 bytes, checksum: 5a2aee56b5048351ab0fc838877f8030 (MD5) Previous issue date: 2013-08-23 / O petróleo é uma mistura complexa, sendo uma das misturas mais desafiadoras para as análises químicas. Muitas técnicas são empregadas para a caracterização dos constituintes do óleo. Entretanto, quando combinamos o altíssimo poder de resolução e exatidão da espectrometria de massas, em especial a Ressonância Ciclotrônica de Íons com Transformada de Fourier, (FT-ICR MS) com fontes de ionização a pressão atmosférica, uma atribuição precisa de mais de 20 000 compostos orgânicos do petróleo pode ser obtida. Na indústria do petróleo existe um grande interesse na análise de ácidos naftênicos e asfaltenos devido a problemas como corrosão e formação de depósitos, que aumentam os custos de produção. Portanto este trabalho tem como objetivo a avaliação da termodegradação de ácidos naftênicos, além do emprego das fontes de ESI, APCI, APPI, LDI e MALDI para aquisição de novos dados relativos a caracterização de asfaltenos. Dois petróleos foram utilizados nos ensaios de termodegradação, o petróleo A com acidez de 2,38 mg KOH g-1 e o petróleo B com 4,79 mg KOH g-1 os quais foram tratados a 280, 300 e 350 ºC pelo período de 2, 4 e 6 horas. De uma maneira geral, as principais classes identificadas para ambas às amostras foram O2, N e NO2, respectivamente. Uma leve redução do NAT e da abundância relativa referente à classe O2 foram observado em função da temperatura e do tempo de envelhecimento (T = 280 → 300 oC e t = 2 → 6 h), sendo que a temperatura de tratamento térmico a 350 ºC demonstrou-se determinante na remoção de compostos da classe O2. O perfil químico de amostras de asfaltenos brasileiros foi avaliado utilizando-se cinco diferentes métodos de ionização em ambos os modos de ionização: positivo e negativo, depois, a distribuição de peso molecular, distribuição de classe, parcelas típicas de número de carbono contra DBE e diagramas van Krevelen foram obtidos e discutidos. Um comportamento atípico foi observado para a fonte de LDI e MALDI (±) FT-ICR MS. Um amplo perfil, de m/z 500-3000, apresentando espaçamento de 24 Da foi observado, e este corresponde a formas alotrópicas de fulereno, C60. Em geral, os asfaltenos apresentaram um elevada proporção de espécies heteroatómicas como: HC, HC [H], N, N [H], N2O, N2O [H], N2, N2 [H], O, O[H] para o modo (+) e N, N [H], NO, NO [H], NO, NO2[H], N2O, N2O[H] para o modo negativo. Nos diagramas de DBE contra o número de carbono, os asfaltenos mostraram para cada valor de DBE uma pequena amplitude de compostos com respeito à NC, proporcionando assim, imagens que formam uma linha de 45 ° entre os eixos CN e DBE. Isto indica que estes compostos não exibem grandes cadeias de alquílicas, sendo composta principalmente por anéis aromáticos. Em geral os diagramas de van Krevelen mostraram alta proporção de compostos com razão H/C ~0,7, corroborando com a existência de espécies altamente aromáticas / Petroleum is a complex mixture, being one of the most challenging mixtures for chemical analyzes. Many techniques are employed to characterize constituents of the oil. However , when we combine the highest resolving power and accuracy of mass spectrometry , especially Ion Cyclotron Resonance Fourier Transform ( FT - ICR MS ) with sources of atmospheric pressure ionization , an assignment need more than 20 000 organic compounds in the oil can be obtained. In the oil industry there is a great interest in the analysis of asphaltenes and naphthenic acids due to problems such as corrosion and deposit formation, which increases production costs. Therefore this study aims to evaluate the thermodegradation of naphthenic acids, besides the use of sources of ESI, APCI, APPI, MALDI and LDI for the acquisition of new data on the characterization of asphaltenes . Two test oils were used in thermodegradation of the oil with an acidity of 2.38 mg KOH g -1 and Oil B with 4.79 mg KOH g- 1 which were treated at 280 , 300 and 350 ° C for a period of 2 , 4 and 6 hours. Generally, the major classes identified for both samples O2, NO2, and C, respectively. A slight reduction of NAT and relative abundance refers to the class O2 were observed as a function of temperature and aging time (T = 280 → 300 ° C t = 2 → 6 h), and the heat treatment temperature at 350 ° C showed a determinant for the removal of class O2. The chemical asphaltenes Brazilian samples was evaluated using five different methods of ionization in both modes of ionization: positive and negative, then the molecular weight distribution, distribution class, typical plots versus carbon number and DBE van Krevelen diagrams were obtained and discussed. An unusual behavior was observed for the LDI and MALDI source ( ± ) FT - ICR MS . A comprehensive profile of m / z 500-3000, with spacing of 24 Da was observed, and this corresponds to allotropes of fullerene C60. In general, the asphaltenes had an heteroatómicas high proportion of species such as HC , HC [ H] , N, [ H] , N2O N2O [ H] N2, N2 [ M ] O O [ H] to mode (+) and N, [ H ] , NO [ H] , NO , NO2, [ H] , N2O N2O [ H ] for the negative mode . In the diagrams DBE against the carbon number , the asphaltenes shown for each value of DBE composed of a small amplitude with respect to NC, thus providing images that form a line of 45 ° between the axes CN and DBE. This indicates that these compounds do not exhibit large chain alkyl, composed mainly of aromatic rings. In general diagrams van Krevelen showed a high proportion of compounds ratio H / C ~ 0.7, confirming the existence of highly aromatic species

Monitoring the impact of anthropogenic activities, particularly in industrial regions, requires ecological screening tools and frameworks that provide a comprehensive understanding of ecosystem responses to environmental changes. Biological indicators, organisms like algae, insects, fish, and sentinel mammals, are critical for assessing ecosystem health, particularly in areas of high industrial activity. The aim of this thesis was to identify a cross-species biomarker that can assess organismal health and environmental stress across various species, organs, and biological matrices. A range of biological systems and signaling pathways related to xenobiotic metabolism, energy homeostasis, immune responses, and stress adaptation were explored, leading to the identification of the Tryptophan-Kynurenine Pathway, which consumes 60-90% of tryptophan in vertebrates. Tryptophan and its metabolites play key roles in diverse physiological processes, including cell growth and maintenance, immunity, disease states, and the coordination of adaptive responses to environmental and dietary cues. This adaptive response suggests that kynurenine-tryptophan ratio (KTR) may serve as a marker for exposure to a variety of environmental stress conditions, including toxicants, nutrient scarcity, predatory stress, and habitat loss—stressors that are prevalent in areas of high industrial activity. In recent years, the KTR is increasingly recognized as a sensitive biomarker in human diseases induced or exacerbated by stress; however, its role in environmental exposure and wildlife health remains unexplored. This thesis explores the question of whether KTR can be utilized as a cross-species biomarker for environmental stress or environmental exposure to toxicants, particularly focusing on the Athabasca Oil Sands Region (AOSR). In vitro studies with mammalian hepatocytes exposed to polycyclic aromatic compounds (PACs): benzo[a]pyrene (BaP), and a Bitumen Water Accommodated Fraction (BitWAF) demonstrated that KTR increases were driven by elevated kynurenine levels, indicating disruption of tryptophan metabolism via the aryl hydrocarbon receptor (AhR). Further studies using acid extractable organics from Oil Sands Process-Affected Water (OSPW), Naphthenic Acid Fraction Components (NAFCs) showed metabolic reprogramming, including altered glucose and fatty acid uptake and mitochondrial dysfunction, mediated through PPARα activation and upregulation of Tdo2, the enzyme responsible for kynurenine production. In vivo studies of longnose and white suckers from the AOSR were conducted to assess the relationship between KTR and CYP1 enzyme activity (EROD). These studies revealed species-specific responses, with an inverse correlation between KTR and EROD in longnose suckers and a direct correlation in white suckers. These findings validate KTR as a biomarker for environmental exposure in wildlife, with significant implications for monitoring ecosystem health. Collectively, this work demonstrates the potential of KTR as a novel biomarker for environmental toxicology, offering a valuable tool for assessing organismal stress across species in response to environmental contaminants. / Thesis / Doctor of Philosophy (PhD) / Human activities, especially industrial operations, can significantly impact the environment. To monitor these effects, scientists use various tools and organisms to assess ecosystem health. This research introduces a new approach to measuring environmental stress in wildlife by focusing on two key molecules: tryptophan and kynurenine. These molecules are part of a conserved biological pathway that helps all organisms manage stress, repair cells, adapt to their environment, and maintain overall health. Tryptophan, an essential amino acid, is broken down into kynurenine, and the balance between them— known as the kynurenine-tryptophan ratio (KTR)—can indicate the level of stress an organism is experiencing. This thesis investigates whether KTR can detect environmental stress caused by industrial activity, particularly from petroleum-derived chemicals in the Athabasca Oil Sands Region (AOSR). In laboratory experiments, mammalian liver cells were exposed to oil sands compounds and complex mixtures from oil sands wastewater. These compounds changed KTR, showing that the liver’s stress response was activated, and tryptophan metabolism was disrupted. The study also found that these chemicals affected cellular energy use and the way cells process fats and sugars. Furthermore, we examined fish species in the AOSR: longnose and white suckers. Results showed that KTR varied depending on the species and the location of exposure. In white suckers, KTR increased in response to stress, while in longnose suckers, it decreased, indicating species-specific responses to environmental changes. Overall, our findings suggest that KTR could serve as a useful tool for measuring environmental stress in different species and ecosystems, especially in areas affected by anthropogenic or industrial activity. Understanding how KTR changes in response to pollution can help scientists better monitor and protect wildlife and ecosystem health.