Trent University

Naphthenic acids are a major contaminant of concern and a focus of much research around remediation of oil sand process affected waters, OSPW. Using activated carbon adsorbents are an attractive option given their low cost of fabrication and implementation. A deeper evaluation of the effect naphthenic acid structural differences have on uptake affinity is warranted. In this thesis an in-depth exploration of naphthenic acid adsorption onto activated carbon is provided including many more model naphthenic acid species than what have been assessed previously in adsorption studies. Both adsorption kinetics and isotherms at the relevant alkaline pH of OSPW using several different carbon adsorbents with pH buffering to simulate the behaviour of real OSPW were evaluated. Given the time sensitive application of most adsorbents towards treating contaminated waters such as OSPW, achieving fast adsorption rates for model naphthenic acids is an important goal worth considering. Textural properties of activated carbon most conducive for fast adsorption kinetics were assessed using several candidate model species. Clear evidence is presented, demonstrating the influence of both the pore size distribution and particle size of porous adsorbents on uptake rates of naphthenic acids, demonstrating that careful optimization of these adsorbent properties can result in adequate uptake rates. Adsorption isotherms were used to assess model naphthenic acid affinity towards activated carbon. Uptake for the model naphthenic acids varied considerably regardless of the activated carbon used, ranging from 350 mg g-1 to near zero highlighting recalcitrant species. The equilibrium data was explored to identify important structural features of these species and key physiochemical properties that influence adsorption. It was demonstrated that certain naphthenic acids are resistant to adsorption when hydrophobic adsorbents are used. Adsorption isotherm modelling helped explore interactions occurring at the interface between naphthenic acids and adsorbent surfaces. Naphthenic acid hydrophobicity was identified as an importance physiochemical property for achieving high adsorption capacities onto activated carbon. Evidence is also presented that indicates favorable hydrogen bonding between naphthenic acids and surface site hydroxyl groups, demonstrating the importance of adsorbent surface functionality for naphthenic acid uptake. The adsorption mechanism was further explored through use of a thermodynamic analysis of the model naphthenic acid system using activated carbon. Standard state enthalpy and isosteric enthalpy of adsorption values were used to further support the proposed mechanisms occurring between model species and activated carbons. This research highlights the challenges associated with removing naphthenic acids from OSPW through adsorption and identifies how adsorbent surface chemistry modification will need to be used to increase the removal efficiency of recalcitrant naphthenic acid species when using activated carbon.

Author Keywords: Activated Carbon, Isotherms, Kinetics, Modelling, Naphthenic Acids, Thermodynamics

This thesis comprises two parts:Part I describes a method to improve the accuracy with which the polarization state of light can be characterized by the rotating quarter-wave plate technique. Through detailed analysis, verified by experiment, we determine the positions of the optic axes of the retarder and linear polarizer, and the wave plate retardance, to better than 1° for typical signal-to-noise ratios. Accurate determination of the Stokes parameters can be achieved using this technique to determine the precise retardance at each of the wavelengths of interest. In Part II, a theoretical analysis of the Fabry-Perot interferometer and its application to quantitative absorption spectroscopy is presented. Specifically the effects of broadening due to non-monochromatic light sources and examples of non-ideal etalon surfaces on the visibility of absorption features are investigated. The potential of this type of spectrometer for ethanol detection in a portable breath analysis application is discussed.

Author Keywords: ABSORPTION SPECTROSCOPY, CALIBRATION, FABRY-PEROT INTERFEROMETER, OPTICS, POLARIMETRY

The crucial role of parents in shaping child development has been widely recognized, with extensive research focusing on various aspects such as parenting styles, attachment relationships, and specific parenting practices. Mind-mindedness, defined as a parent's ability to recognize and understand their child's mental states, is emerging as an important factor in child development. The present study sought to investigate cross-cultural differences in maternal mind-mindedness, parenting practices, and their relationship to child compliance in China and Canada. The participants included 136 Chinese mother-child dyads and 83 Canadian mother-child dyads, with children ranging from ages 4 to 7. Maternal mind-mindedness, parenting practices, and child compliance were coded through observational method. Results suggest that while Canadian mothers were more mind-minded, Chinese mothers were more power assertive. Moreover, maternal parenting practices mediated the relationship between mind-mindedness and child compliance in China. This study cultivated a culturally sensitive understanding of the parent-child relationship.

Author Keywords: Child Compliance, Culture, Maternal Involvement, Mind-Mindedness, Parenting, Power Assertion

The Great Lakes represent nearly a fifth of the global freshwater surface supply, and support culturally, economically, and ecologically important fish species such as Walleye (Sander vitreus). With water temperatures projected to rise by several degrees in the coming century, understanding the energetic impacts on fishes is crucial for effective habitat and fisheries management. I measured the swimming performance, accelerometer-based activity, and metabolism of walleye in relation to body size, sex, and water temperature to assess potential responses to climate variability. Both acceleration and swim speed predicted metabolic rate with reasonable accuracy. Temperature had a positive effect on oxygen consumption whereas body mass had a negative effect. Critical swimming speed increased with temperature, and tailbeat frequency had positive relationships with swim speed and acceleration. My laboratory-based calibrations should enable remote field monitoring of energy use of walleye (via accelerometers) and help conserve an important species through bioenergetic modelling.

Author Keywords: accelerometry, bioenergetics, climate change, metabolism, respirometry, walleye

The oil sands industry is producing large volumes of tailings waste reaching 2 billion cubic meters by 2034 In this study, the industrial standard flocculant, high molecular weight PAM, was grafted from the surface of activated carbon (AC). This material was designed to increase the flocculant's hydrophobicity and density. Different molecular weight PAM was grafted from AC with different AC contents and particle sizes (AC-PAMs). The AC-PAMs were synthesized by surface-initiated atom transfer radical polymerization (SI-ATRP). The AC-PAMs achieved molecular weights 107 – 5,600 kg/mol and AC content of 0.2 – 5.8% on <0.1 and 0.1 – 0.5 mm AC particle diameters. AC-PAM achieved higher solids contents up to 51 wt% using AC-PAM with 5.1 wt% AC due to the grafting from a hydrophobic AC core. To summarize, our work shows the successful grafting of PAM from AC and its potential as a flocculant for mature fine tailings.

Author Keywords: activate carbon, atom transfer radical polymization, flocculation, grafting-from, polyacrylamide, surface-initiated polymerization

The Holocene Climate Optimum turned the Gobi Desert from a mainly grassland habitat into a mosaic landscape composed of dune-fields, wetlands and high elevation forests (Janz 2012, 2016; Janz et al. 2017). The populations that inhabited the region at the time adapted by adopting new settlement patterns and tools, which might have allowed them to better exploit a new wide range of resources (Janz 2012, 2016; Janz et al. 2017). This thesis investigates the emergence of ground stone tool technology in the Gobi Desert and its connection with wild plant use by foragers at the time. Twenty-one implements were studied through experimental, use-wear and residue analysis. The results reveal that the tools were used to process several categories of wild plants. By conducting this investigation in legacy collections, this study also proved that archaeological micro-botanical evidence can be recovered from such materials and that their contamination can be assessed through specific protocols.

Author Keywords: Gobi Desert;, Ground Stone Tools;, Macro-lithics;, Mongolia;, Neolithic;, Northeast Asia;

In Ontario, farmers commonly use a MZ (Maize (Zea mays L.))-SB (Soybean (Glycine max))/WW (Winter wheat (Triticum aestivum)) – CC (mixed cover crop) rotation to maximize economic benefits. This study aimed to investigate the short-term impacts of the crop rotation phases and their associated management practices in this diversified cash crop rotation on soil health and the abundance of nitrogen (N)-cycling soil microbial communities (SMCs). Additionally, the abundance of N-cycling SMCs and plant-available N in both surface (0-5 cm) and rooting zone (5-15 cm) depths were characterized in tile-drained (TD) and non-TD fields. In the present study, soils collected under the CC phase had the highest labile carbon levels (10-17% higher) and water-stable aggregates (35-50% higher) compared to the other two crop phases. Lower nitrifying (amoA) gene abundances and soil NO3--N levels were observed in the CC phase compared to the MZ and SB-WW phases, suggesting a potential for decreased nitrification in the CC phase. The presence of SB potentially influenced the soil N concentration in the subsequent WW phase likely due to the release of symbiotically fixed N in the SB-WW phase. Further, higher amoA abundances and NO3--N in the SB-WW phase imply a potential for increased nitrification in the SB-WW phase. Additionally, higher amoA/nosZI and nirS+nirK/nosZI ratios were observed in the MZ phase than in SB-WW and CC phases, suggesting a potential capacity for increased N2O emissions from the reactions mediated by N-cycling SMCs in soils planted to MZ during fall sampling days. In the TD and NTD field study, higher NO3--N levels were observed in TD-SB-WW fields at 5-15 cm vs. 0-5 cm depths, which was possibly facilitated by tile drainage. The TD-CC fields displayed higher nosZI gene abundances and lower nirS+nirK/nosZI abundance ratios, suggesting a greater potential capacity for decreased N2O emissions in soils planted to CCs during the spring sampling days. When examining changes in plant available N by soil depth, reduced downward movement of NO3- through shallow soil depths (0-15 cm depth) was observed in the CC phase compared to cash crops. This short-term study highlights the potential contribution of the CC phase, particularly within TD agricultural fields, for improving soil health and reducing potential N2O emissions. Together, these results suggest that management-associated differences in crop rotation phases have temporary effects on soil health and the abundance of SMCs. Future studies linking N-cycling SMC's potential activity and field-scale N2O fluxes will provide a better insight into the longer-term sustainability of Ontario's cash crop management systems.

Author Keywords: denitrification, maize-soybean-winter wheat- cover crop rotation, nitrification, soil depth, Sustainable agriculture, tile-drainage

In an effort to improve upon existing analytical methods, electrochemical sensors offer portable, cost-effective alternatives to traditional lab-based techniques. Recent advances in supramolecular chemistry offer a unique alternative to achieve high selectivity while also benefitting from facile scaling for mass production. Thus, by incorporating host-guest chemistry with electrochemical sensors, the development of simple and selective sensors is possible. To that extent, novel hosts and electroactive ion pairs were investigated for their ability to transduce an electrochemical signal representative of host-guest complexation. Results demonstrated that the upper rim modifications of resorcinarene hosts attenuated their affinity for electroactive probes whilst maintaining structural integrity upon extended cycling. Further work revealed that guests may be directly quantified via their complexation with electroactive hosts. The sensing method was further validated by quantification of surfactant pollutants in the Otonabee River. Through a fundamental understanding of the electrochemical behaviour of host-guest systems a general sensing platform can be developed, where hosts are interchangeable for specificity towards any desired analyte. Therefore, moving away from expensive lab-based methods and significantly reducing the barriers for biological or environmental monitoring.

Author Keywords: Electrochemistry, Ferrocene, Host-Guest, Resorcinarenes, Supramolecular Chemistry, Surfactants

The detection of ciguatoxins (CTXs) in biological samples is challenging due to their low concentrations, the presence of various congeners, and the absence of standardized methods. This study uses high resolution mass spectrometry (HRMS) with P-CTX-3B as a reference standard. The protonated molecules ([M+H]+) were most prevalent, especially when acetonitrile/water was utilized, providing enhanced sensitivity. Optimized collision energies of 15 eV for protonated molecules and flow rates of 10 µl/min enhance sensitivity and peak intensities, respectively. Acetonitrile/water (ACN/H2O) is recommended as the primary solvent for HRMS method, an aspect underexplored in existing literature. The detection of CTX-3B in fish tissue samples proved to be challenging, caused by variations in ion peak intensities and matrix effects, requiring a deeper exploration of the impact of complex matrices on CTX detection. The study emphasizes the need for a reliable internal standard to mitigate these effects and highlights the ongoing challenge of developing a rapid, simple, and sensitive detection method. The study's specific focus on the P-CTX-3B analogue significantly contributes to methodology development for this congener, serving as a foundational step in understanding and detecting CTX. Despite notable progress, the study acknowledges the absence of an ideal assay, outlining key challenges for future research on ciguatera analysis. It underscores the continuous necessity for method reevaluation, testing, and the broader goal of establishing a more clarified and rugged method for the identification of CTX in fish.

Author Keywords: Analytical Chemistry, Ciguatera Fish Poisoning, Ciguatoxin, High-Resolution Mass Spectrometry, Optimization, P-CTX-3B

Molecular and genomic tools provide a deeper understanding of the ecology and evolution of species and their capacity to adapt to changing selective pressures, where diversity is presumedly linked to higher fitness and evolutionary potential. Molecular tools can also illustrate how historical processes affect contemporary genetic variation to predict how current population trends may influence future genetic diversity. Genomic investigations increasingly extend beyond variation within host genomes to include diversity of their associated microbiomes, recognized to influence host/environment interactions and adaptation. Muskoxen (Ovibos moschatus) are iconic, Arctic herbivores of ecological, economic, and cultural significance. Demographically, most mainland muskox populations have remained stable or grown over the last century, yet the biggest herds, found on Victoria and Banks Islands (Nunavut and the Northwest Territories, Canada) have experienced recent and drastic population declines. These Arctic island population declines have been associated with warming trends leading to shifting ranges of forage biodiversity, and pathogen expansions directly associated with increased mortality. Genomic investigations have the potential to enhance understanding of these contrasting trends and the adaptive capacities of muskox to cope with rapid ecological change. In this thesis, I assess genetic, genomic, microbiome and diet diversity to better understand the ecology, and evolution of muskoxen. I found extremely low levels of genetic variation associated with population bottlenecks coinciding with major glaciation events and contemporarily low levels of gene flow among populations. Whole genome analyses identified signatures of selection between muskox populations, providing a genetic basis for the divergence of two previously proposed muskox subspecies. Significant differences in diversity, effective population size and inbreeding among subspecies suggests animals from Arctic islands and Greenland are more vulnerable to environmental change. Molecular investigations of diet and microbiome diversity reflected unique capacities of muskoxen to survive on high-fiber forage and exploit shifts in Arctic vegetation that may include continued shrubification. Overall, these data provide insight into the complex relationship between genetic diversity and changing environments, setting a foundation for expanded future investigations of muskox seeking to promote the future viability of this species.

Author Keywords: Genetic Diversity, Genome Assembly, Metabarcoding, Microsatellites, Muskox, Persistence