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The environmental impact of bitumen mining in the Athabasca region of Canada is of growing concern. Among these concerns is the need and difficulty to remediate and reclaim affected land, including tailing sands (TS), a byproduct of the hot water extraction used to separate bitumen from solid materials. Current reclamation methods consist of multiple steps and take several decades to be effective. The primary reason for the difficulty in reclaiming disturbed land is the harsh environment found within the TS combined with the scale of the problem. TS are extremely nutrient poor, having below-detectable levels of NPK and extremely low C and S. In addition to this TS have pHs outside of environmental normals, and are hydrophobic due to residual hydrocarbons. Previously, an endophytic fungus, Trichoderma harzianum strain TSTh20-1, was isolated from pioneer plants growing naturally on TS sites, and was found to promote plant growth on TS. In my study TSTh20-1 was also found to increase the rate of drought recovery, and to enhance seed germination rates on a variety of soils. Suitable application methods were explored for this endophyte, including seed coatings, granules, as well as direct application to plant/soil. Regardless of method, TSTh20-1 was found to successfully colonize the plants. Twenty-four species of grasses, forbs, and legumes were tested for their ability to grow on TS. The four most successful species (Trifolium repens, Bouteloua gracilis, Medicago sativa, and Elymus trachycaulus) were put into a seed mixture for use in experiments. In mesocosm-scale experiments, plant health and soil parameters were measured after 2 months of growth. Hydrocarbon analysis of the first mesocosm showed a 2.7-fold increase in total hydrocarbons when TSTh20-1 and plants were present, suggesting degradation of large hydrocarbons beyond the scope of the analysis. A repeat experiment using a different source of tailings did not yield this same result. This is most likely due using a source of tailings that had substantially different chemical characteristics. TSTh20-1 was also analyzed for its ability to produce plant hormones or siderophores, to increase peroxidase enzyme activity, to protect plants from reactive oxygen species, and to solubilize phosphate precipitates from soil. All of these are known mechanisms microbes use to promote plant growth.

Recent experimental and simulation studies -conducted at the Department of Petroleum Engineering at Texas A&M University - confirm oil production is accelerated when propane is used as an additive during steam injection. To better understand this phenomenon, distillation experiments were performed using seven-component synthetic oil consisting of equal weights of the following alkanes: n-C5, n-C6, n-C7, n-C8, n-C9, nC10, and n-C15. For comparison purposes, three distillation processes were investigated: dry-, steam-, and steam-propane-distillation, the latter at a propane:steam mass ratio of 0.05. The injection rate of nitrogen during dry-and steam-distillation was the same as that of propane during steam-propane distillation, 0.025 g/min, with steam injection rate kept at 0.5 g/min. The distillation temperatures ranged from 115°C to 300°C and were increased in steps of 10°C. The cell was kept at each temperature plateau (cut) for 30 minutes. Distillation pressures ranged from 0 psig for dry distillation to 998 psig for steam-and steam-propane distillation. The temperature-pressure combination used represented 15°C superheated steam conditions. Distillate samples were collected at each cut, and the volume and weight of water and hydrocarbon measured. In addition, the composition of the hydrocarbon distillate was measured using a gas chromatograph. Main results of the study may be summarized as follows. First, the hydrocarbon yield at 125°C is highest with steam-propane distillation (74 wt%) compared to steam distillation (58 wt%), and lowest with dry distillation (36 wt%). This explains in part the oil production acceleration observed in steam-propane displacement experiments. Second, the final hydrocarbon yield at 300°C however is the same for the three distillation processes. This observation is in line with the fact that oil recoveries were very similar in steam- and steam-propane displacement experiments. Third, based on the yields of individual hydrocarbon components, steam-propane distillation lowers the apparent boiling points of the hydrocarbons significantly. This phenomenon may be the most fundamental effect of propane on hydrocarbon distillation, which results in a higher yield during steam-propane distillation and oil production acceleration during steam-propane displacement. Fourth, experimental K-values are higher in distillations with steam-propane for the components n-hexane, n-heptane, n-octane, and n-nonane. Fifth, vapor fugacity coefficients for each component are higher in distillations with steam-propane than with steam. Finally, Gibbs excess energy is overall lower in distillations with steam-propane than with steam. The experimental results clearly indicate the importance of distillation on oil recovery during steam-or steam-propane injection. The experimental procedure and method of analysis developed in this study (for synthetic oil) will be beneficial to future researchers in understanding the effect of propane as steam additive on actual crude oils.

Many factors such as rift history, crustal structure and distribution of high thermal conductivity salt bodies throughout the sediment pile affect the present day thermal structure of the deepwater Scotian Slope. Understanding the basin's thermal evolution is crucial in determining the hydrocarbon maturation potential of this deepwater frontier basin. The Late Jurassic Verrill Canyon Formation of the deepwater slope has been inferred as the primary source rock interval for the Scotian Basin. However, to date, only twelve boreholes have sampled the Scotian Slope, and of these, none penetrate beneath the uppermost Jurassic sediments. Therefore, the distribution and maturation of deeper source rock intervals through standard vitrinite reflectance analysis remains unknown. In this study we attempt to better constrain the thermal history and maturation potential of the central Scotian Slope using a combination of recently acquired seafloor heat flow data, 2D seismic reflection data, available well data, simple lithospheric rift models and 3D thermal and petroleum systems modelling. We have derived a method of combining seafloor heat flow data with simple lithospheric rift models to provide first order constraints on the hydrocarbon maturation potential of frontier basins in dynamic 3D thermal models for regions lacking vitrinite reflectance and temperature data from boreholes. In July 2008, 47 seafloor heat flow measurements were acquired across the central Scotian Slope in an attempt to better constrain the region's thermal structure. Locations seaward of the salt diapiric province, thus unaffected by the high thermal conductivity of salt, recorded seafloor heat flow values of ~41-46 mWm-2. Significant increases in seafloor heat flow were noted for stations overlying salt diapiric structures, reaching values upwards of 72 mWm-2. The seafloor heat flow data have been corrected to remove the conductive effects of salt and the cooling effects of seafloor sedimentation on measured heat flow. The corrected data are compared with basal heat flux predictions from simple lithospheric rift models as constrained using crustal ( ) and lithospheric ( ) stretching factors after Wu (2007) to constrain heat flux history through time. Seafloor heat flow and simple modelling results suggest present day basal heat flux does not vary significantly across the slope. Present day basal heat flux across the central Scotian Slope is ~44-46 mWm-2. Basal heat flux curves from simple lithospheric rift models are used to constrain the heat flux history in 3D thermal and petroleum systems models of the central Scotian Slope. Numerous basal heat flux histories were tested to determine which heat flux history yielded the best match between modelled and measured seafloor heat flow data and to determine how varying basal heat flux affects the modelled hydrocarbon maturation of Verrill Canyon source rocks. The basal heat flux history which yielded the best match to measured seafloor heat flow data suggests that the Late Jurassic source rock interval rests primarily within the late oil window. Variations in radiogenic heat production across the margin associated with thickening continental crust were tested and suggest that significant variations in both maturation and seafloor heat flow may occur if radiogenic heat producing elements occur in high enough concentrations in the crust.

Knowledge of flammability limits is essential in the prevention of fire and explosion. There are two limits of flammability, upper flammability limit (UFL) and lower flammability limit (LFL), which define the flammable region of a combustible gas/vapor. This research focuses on the flammability limits of hydrogen and its binary mixtures with light hydrocarbons (methane, ethane, n-butane, and ethylene) at sub-atmospheric pressures. The flammability limits of hydrogen, light hydrocarbons, and binary mixtures of hydrogen and each hydrocarbon were determined experimentally at room temperature (20ºC) and initial pressures ranging from 1.0 atm to 0.1 atm. The experiments were conducted in a closed cylindrical stainless steel vessel with upward flame propagation. It was found that the flammable region of hydrogen initially widens when the pressure decreases from 1.0 atm to 0.3 atm, then narrows with the further decrease of pressure. In contrast, the flammable regions of the hydrocarbons narrow when the pressure decreases. For hydrogen and the hydrocarbons, pressure has a much greater impact on the UFLs than on the LFLs. For binary mixtures of hydrogen and the hydrocarbons, the flammable regions of all mixtures widen when the fraction of hydrogen in the mixture increases. When the pressure decreases, the flammable regions of all mixtures narrow. The applications of Le Chatelier’s rule and the Calculated Adiabatic Flame Temperature (CAFT) model to the flammability limits of the mixtures were verified. It was found that Le Chatelier’s rule could predict the flammability limits much better than the CAFT model. The adiabatic flame temperatures (AFTs), an important parameter in the risk assessment of fire and explosion, of hydrogen and the hydrocarbons were also calculated. The influence of sub-atmospheric pressures on the AFTs was investigated. A linear relationship between the AFT and the corresponding flammability limit is derived. Furthermore, the consequence of fire relating to hydrogen and the hydrocarbons is discussed based on the AFTs of the chemicals.

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This research investigates a novel approach to methanol production from methane. The high use of fossil fuels in New Zealand and around the world causes global warming. Using clearer, renewable fuels the problem could potentially be reduced. Biomass energy is energy stored in organic matter such as plants and animals and is one of the options for a cleaner, renewable energy source. A common biofuel is methane that is produced by anaerobic digestion. Although methane is a good fuel, the energy is more accessible if it is converted to methanol. While technology exists to produce methanol from methane, these processes are thermo-chemical and require large scale production to be economic. Nitrosomonas europaea, a nitrifying bacterium, has been shown to oxidize methane to methanol (Hyman and Wood 1983). This research investigates the possibility of converting methane into methanol using immobilized N. europaea for use in smaller applications. A trickle bed bioreactor was developed, containing a pure culture of N. europaea immobilized in a biofilm on ceramic raschig rings. The reactor had a biomass concentration of 7.82 ± 0.43 g VSS/l. This was between 4 – 15 times higher than other systems aimed at biologically producing methanol. However, the immobilization dramatically affected the methanol production ability of the cells. Methanol was shown to be produced by the immobilized cells with a maximum production activity of 0.12 ± 0.08 mmol/gVSS.hr. This activity was much lower than the typical reported value of 1.0 mmol/g dry weight.hr (Hyman and Wood 1983). The maximum methanol concentration achieved in this system was 0.129 ± 0.102 mM, significantly lower than previous reported values, ranging between 0.6 mM and 2 mM (Chapman, Gostomski, and Thiele 2004). The results also showed that the addition of methane had an effect on the energy gaining metabolism (ammonia oxidation) of the bacteria, reducing the ammonia oxidation capacity by up to 70%. It was concluded, because of the low methanol production activity and the low methanol concentrations produced, that this system was not suitable for a methanol biosynthesis process.

The main goal of this thesis was to develop new methods and knowledge that will explain and predict species differences in sensitivity to dioxin-like compounds (DLCs) in birds. The important achievements and results obtained from the four experimental chapters of this thesis are summarized as follow: (1) an efficient luciferase reporter gene (LRG) assay was developed for use with 96-well cell culture plates; (2) the results obtained from LRG assay were shown to be highly correlated to available in ovo toxicity data; (3) amino acids at positions 324 and 380 within the aryl hydrocarbon receptor 1 ligand binding domain (AHR1 LBD) were shown to be responsible for reduced Japanese quail (Coturnix japonica) AHR1 activity to induce a dioxin-responsive reporter gene in comparison to chicken (Gallus gallus domesticus), and ring-necked pheasant (Phasianus colchicus) AHR1 in response to different DLCs; (4) AHR1 LBD sequences of 86 avian species were studied and differences at amino acid sites 256, 257, 297, 324, 337 and 380 were identified. It was discovered that only positions 324 and 380 play a role in AHR1 activity to induce a dioxin-responsive gene; (5) in COS-7 cells expressing chicken AHR1, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) are equipotent inducers of the reporter gene and bind with similar affinity to chicken AHR1, however, in the cells expressing pheasant, Japanese quail and common tern (Sterna hirundo) AHR1, PeCDF is a stronger inducer than TCDD. PeCDF also binds with higher affinity to pheasant and quail AHR1 than TCDD. The results of this thesis show that embryo lethal effect of DLCs in avian species can be predicted by use of two new non-lethal methods: (1) the LRG assay and (2) determination of the identity of the amino acids at positions 324 and 380. The findings and methods described in this thesis will be of use for environmental risk assessments of DLCs.

<p>Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants formed from the incomplete combustion of fossil fuels and are found in the environment as complex mixtures. PAHs are developmentally toxic to fish, causing yolk sac edema, hemorrhaging, craniofacial malformations and cardiac defects including impaired heart looping, elongated heart, decreased blood flow, and pericardial effusion. Previous research has shown that many of the toxic effects of PAHs are mediated through the aryl hydrocarbon receptor (AHR), which upregulates phase I and II metabolic genes, but the underlying mechanisms of PAH-induced toxicity are not yet known. The primary goal of this dissertation was to better understand the molecular mechanisms by which PAH mixtures cause developmental toxicity in fish. To this end, the zebrafish (Danio rerio) was used as a developmental model. Simple mixtures consisting of a PAH that is an AHR agonist (benzo[a]pyrene or benzo[k]fluoranthene) and a PAH that is a cytochrome P450 1 (CYP1) inhibitor (fluoranthene) were used in these experiments along with the dioxin-like compound 3,3',4,4',5-pentachlorobiphenyl (PCB-126). Morpholino gene knockdown was used to examine the role of specific genes in response to PAHs, gene expression changes in response to PAH exposures were examined via QPCR, quantification of pericardial effusion was used as a metric for cardiac toxicity, and CYP1 activity was measured as an indication of AHR pathway induction. First, PAH mixtures consisting of an AHR agonist (BkF) and a CYP1 inhibitor (FL) induced cardiac toxicity that was preceded by upregulation of CYP1 and redox-responsive gene expression, and these effects were dependent upon the AHR2. Second, knockdown of glutathione s-transferase pi class 2 (GSTp2), part of phase II metabolism, exacerbated PAH-induced toxicity but did not affect PCB-126-induced toxicity. Third, knockdown of another isoform of the AHR, AHR1, exacerbated PAH- and PCB-126-induced toxicity and increased CYP1 activity but did not affect CYP expression in response to these agonists. Simultaneous knockdown of AHR1A and AHR2 did not exacerbate nor ameliorate PAH-induced toxicity but did prevent PCB-126-induced toxicity. Fourth, to examine AHR2-dependent and AHR2-independent gene induction in zebrafish hearts in response to PAHs, microarrays were used. Gene expression changes caused by PAHs were largely AHR2-dependent and consisted of genes involved in cell adhesion, oxidation-reduction, and TGF-&beta signaling processes as well as genes involved in heart structure and function. These findings help to elucidate how PAHs elicit deformities during development and highlight differences between PAHs and other AHR agonists. Additionally, these experiments have identified other genes in addition to AHR2 that are involved in mediating or responding to the toxicity of PAHs.</p> / Dissertation