Graduate Theses & Dissertations

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Assessing Measured and Perceived Risks to Drinking Water Sources
Microcontaminants originating from wastewater effluent and run-off from agricultural lands may be present in the sources of drinking water for rural and Indigenous communities in mixed-use watersheds. In this study, a convergent parallel mixed-methods design was applied to assess measured and perceived risks of contamination in the sources of drinking water for two communities; the Six Nations of the Grand River community in Ontario and the community of Soufriere in St. Lucia, West Indies. The overall goal of the project was to assess how measured and perceived risks of exposure to chemical and biological contaminants in drinking water sources could inform water management strategies for the communities. Quantitative data obtained from the analysis of water samples collected indicated that the highest levels and occurrence of fecal bacteria were found in the Soufriere watershed while the highest concentrations and occurrence of pesticides were found in the Grand River watershed. In the Grand River watershed, conventional treatment of water followed by activated carbon filtration and UV disinfection removed fecal bacteria and also removed many chemical microcontaminants with efficiencies as high as 98%. Data from both watersheds indicated that there was a strong positive correlation between the levels of caffeine and sucralose (i.e. indicators of wastewater contamination) in water samples and the levels of either Total Coliforms or fecal bacteria of human origin. Human health risk assessments of individual pesticides and pesticide mixtures performed by applying a hazard quotient (HQ) and hazard index (HI) model, respectively indicated that there were no apparent risks to human health from those microcontaminants. Qualitative data obtained from face-to-face interviews with water managers and health professionals working in the two communities, which were collected and analysed concurrently but independently, illustrated that there were cross-cultural similarities and differences in factors influencing the perceptions of risks associated with the sources of drinking water. These perceptions of risks were mainly influenced by factors such as heuristics or informal and informal reasoning, cognitive-affective factors, social-political institutions and cultural factors. These factors may have also influenced water managers and health professionals, as they often recommended more “soft” strategies for managing water resources in the communities. Key words: pesticides, fecal bacteria, microcontaminants, POCIS, measured risks, perceived risks, water management, First Nations, Grand River, Soufriere, St. Lucia Author Keywords: fecal bacteria, measured risks, microcontaminants, perceived risks, POCIS, water management
Assessing effects and fate of environmental contaminants in invasive, native, and endangered macrophytes
Macrophytes play an important role in aquatic ecosystems, and thus are integral to ecological risk assessments of environmental contaminants. In this dissertation, I address gaps in the assessments of contaminant fate and effects in macrophytes, with focus on glyphosate herbicide use for invasive plant control. First, I evaluated the suitability of Typha as future standard test species to represent emergent macrophytes in risk assessments. I concluded that Typha is ecologically relevant, straight-forward to grow, and its sensitivity can be assessed with various morphological and physiological endpoints. Second, I assessed effects from glyphosate (Roundup WeatherMAX® formulation) spray drift exposure on emergent non-target macrophytes. I performed toxicity tests with five taxa, Phragmites australis, Typha × glauca, Typha latifolia, Ammannia robusta, and Sida hermaphrodita, which in Canada collectively represent invasive, native, and endangered species. I found significant differences in glyphosate sensitivity among genera, and all species’ growth was adversely affected at concentrations as low as 0.1% (0.54 g/L), much below the currently used rate (5%, 27 g/L). Third, I assessed the potential for glyphosate accumulation in and release from treated plant tissues. I found that P. australis and T. × glauca accumulate glyphosate following spray treatment, and that accumulated glyphosate can leach out of treated plant tissues upon their submergence in water. Finally, I assessed effects of released glyphosate on non-target macrophytes. I found that P. australis and T. × glauca leachate containing glyphosate residues can stimulate the germination and seedling growth of T. latifolia, but can exert an inhibiting effect on A. robusta, although leachate without glyphosate caused similar responses in both plants. Additionally, I found no negative effects in A. robusta when exposed to glyphosate residues in surface water, or when grown with rhizosphere contact to an invasive plant that was wicked (touched) with glyphosate. My results show that non-target macrophytes can be at risk from glyphosate spray for invasive plant control, but risks can be mitigated through informed ecosystem management activities, such as targeted wick-applications or removing plant litter. Integrating contaminant fate and effect assessments with emergent macrophytes into ecological risk assessments can support the protection of diverse macrophyte communities. Author Keywords: Ecosystem management, Ecotoxicology, Glyphosate, Herbicide, Invasive plant, Species at risk
Digital Elevation Models and Viewshed Analysis
This thesis approaches the issue of Viewshed Analysis and how it can impact the understanding of a medieval environment. Centered on the High Medieval period of Cilicia, in what is today Southwestern Turkey, the precision of Viewsheds in a complex terrain is evaluated, and the role of the fortifications in the environment is expanded upon. The maps that were generated for this thesis demonstrate that the use of free datasets must be done with caution, and that the use of more than one dataset is crucial in trying to create a clearer picture of the environment. The examination of four separate sets of fortifications within the region leads to new questions about the role of fortifications in the region, as well as a better understanding of what groups such as the Armenian Cilicians and the Knights Templar were doing in the High Medieval period. Finally, conclusions are made regarding the future impact of GIS based studies, and how they can help scholars understand Ancient and Medieval landscapes. Author Keywords: Armenian Cilicia, Fortifications, GIS, Viewshed
Anishinaabe Motherhood
The purpose of this qualitative study is to investigate Anishinaabe women’s Traditional Teachings and pedagogies in a contemporary context. Through this exploration, I have uncovered the tensions, challenges, and strengths that Anishinaabe gaashiyag (mothers) face when engaging with these Traditional Teachings and pedagogies. The research methodology I have used is a branch of grounded theory called the Anishinaabe Research Methodology, and it is integral to the Anishinaabe principles of living called the Seven Grandparent Teachings: Wisdom, Love, Respect, Bravery, Honesty, Humility, and Truth. I used a research method called the Nbwaachiwi (the art of visiting) method. I used the ‘Aunties kitchen table’ style of knowledge collection, where it is open-ended and one-on-one - like you would be at your auntie's kitchen table, sharing stories and having tea. By utilizing these principles, I conducted my research through the Anishinaabe-aadiziwin (culture and language – way of life) paradigm. I addressed multilayered Anishinaabe teachings and many connections to the land and spirituality. I have found that Anishinaabe gaashiyag feel pressure to adopt Western modes of raising their children. However, some young women are returning to the traditional Anishinaabe teachings by using traditional birthing techniques, tiknigaans (traditional baby carriers), and evolving our cultural practices to fit modern ways of living. The knowledge I present within this paper can inform mothers who want to learn Traditional Teachings and pedagogies, and thereby resist ongoing intergeneration trauma and colonization. New generations are identifying what the negative effects on raising Anishinaabe children and taking a stand to break ongoing trauma and abuse so that their children do not have to be subjected to it. These mothers are informed about cultural and Traditional Teachings with the hope that they can use this knowledge to assist them on their path to, and during, motherhood. Given the determination of these young mothers to raise their babies using Anishinaabe traditional methods, the future identities and lives of their children may be significantly better in a cultural sense than their predecessors. They will be the products of their mothers’ commitment to the resurgence of Anishinaabe maternal teachings and pedagogies. Author Keywords: Anishinaabe, Indigenous Motherhood, Motherhood, Parenting, Pedagogies, Teachings
Non-Hippocampal Memory Systems Contributing to Reinstated Context Memory
Damage to the hippocampus (HPC) typically causes retrograde amnesia for contextual fear conditioning. Reinstating the conditioning over several sessions, however, can mitigate the retrograde amnesic effects. Reinstatements, thus, establish a sufficiently strong memory in non-HPC systems to no longer require the HPC for expression, meaning that it has become HPC independent. This thesis aimed to determine the structures comprising the non-HPC system supporting reinstated context fear memory. The contribution of the perirhinal cortex (PRH) and the anterior cingulate cortex (ACC) were examined because of their established role in context memory. Initially, it was demonstrated that HPC damage indeed causes retrograde amnesia for single session, but not reinstated, contextual fear conditioning. Then, it was demonstrated that combined HPC and PRH damage causes retrograde amnesia for reinstated contextual fear conditioning, whereas combined HPC and ACC damage had lesser effects. Therefore, the PRH is a key structure within the non-HPC memory system for reinstated context fear memory. Author Keywords: anterior cingulate cortex, contextual fear conditioning, hippocampus, memory, perirhinal cortex, retrograde amnesia
Influence of Habitat on Woodland Caribou Site Fidelity
Site fidelity is the behaviour of individuals to return to the same location; for female woodland caribou it may reflect reproductive success and depend on habitat quality. I investigated the influence of landscape and disturbance conditions on fidelity among three populations in Manitoba and Ontario, Canada. Habitat classifications were based on Forest Resource Inventory (FRI) and Landsat TM landcover maps. A total of 261 sites were ground-truthed to determine mapping accuracy. An amalgamated map incorporating FRI and Landsat TM data was estimated from field measurements to have an overall accuracy of 69.0%. Site fidelity was expressed as the distance between consecutive-year locations of individuals and was investigated during five week-long periods representing calving, early and late post-calving, winter, and breeding. Site fidelity was strongest during the post-calving seasons and weakest during the winter. Habitat had little influence on site fidelity in all seasons, excepting winter, even under highly disturbed conditions, suggesting maintenance of fidelity may be a maladaptive trait. Individual variation proved a strong predictor and cursory mapping indicated that caribou may return to sites visited two or more years earlier. Conservation management and policy should recognize that site fidelity may represent an ecological trap. Author Keywords: calving, disturbance, habitat, movement, Rangifer tarandus caribou, site fidelity
Lipid-derived Thermoplastic Poly(ester urethane)s
Thermoplastic poly(ester urethane)s (TPEU)s derived from vegetable oils possess inferior physical properties compared to their entirely petroleum-based counterparts due to the structural limitations and lower reactivity of the precursor lipid-derived monomers. The present work shows that high molecular weight of TPEUs with enhanced performance can be obtained from lipid-derived monomers via (i) the synthesis of polyester diols with controlled molecular weights, (ii) the tuning of the functional group stoichiometry of the polyester diols and the diisocyanate during polymerization, (iii) the degree of polymerization (iv) the control of the hard segment hydrogen bond density and distribution via the use of a chain extender and (v) different polymerization protocols. Solvent-resistant TPEUs with high molecular weight displaying polyethylene-like behavior and controlled polyester and urethane segment phase separation were obtained. Structure-property investigations revealed that the thermal transition temperatures and tensile properties increased and eventually plateaued with increasing molecular weight. Novel segmented TPEUs possessed high phase separation and showed elastomeric properties such as low modulus and high elongation analogous to rubber. The response of the structurally optimized TPEUs to environmental degradation was also established by subjecting the TPEUs to hydrothermal ageing. TPEUs exhibited thermal and mechanical properties that were comparable to commercially available entirely petroleum-based counterparts, and that could be tuned in order to achieve enhanced physical properties and controlled degradability. Author Keywords: Hydrothermal degradation, Molecular weight control, Polyester diols, Renewable resources, Structure-property relationships, Thermoplastic poly(ester urethane)s
Relationships between Dissolved Organic Matter and Vanadium Speciation in the Churchill River, MB and the Mackenzie River Basin, NWT using diffusive gradients in thin films (DGT)
This study examines the influence of dissolved organic matter (DOM) on dissolved vanadium (V) speciation in the Churchill River and Great Slave Lake using diffusive gradients in thin film (DGT). Vanadium is commonly found in natural environments such as rivers, lakes and oceans. It regulates normal cell growth, but in excessive amounts, it can have toxic effects on human and aquatic organisms. The use of in situ, time integrated DGT devices allows to better (1) monitor the most bioavailable fraction of V, the DGT-labile V, in Arctic Rivers and (2) assess the influence of DOM on dissolved V speciation. Higher DGT-labile V was found in the the central regions of the Mackenzie River (MR), with an average of 7.7 ± 2.3 nM, likely due to sediment leaching and permafrost thawing. The Churchill River and Great Slave Lake (GSL) showed lower DGT-labile V levels (2.2 ± 1.6 nM and 3.6 ± 2.7 nM, respectively), compared to central regions in MR. The CR DGT-labile V concentrations was positively correlated to protein-like DOM concentration and abundance (r = 0.3, p < 0.05). The data collected from this study will help in developing new strategies regarding environmental health and impact assessments of environmentally hazardous waste that consist of potentially high levels of toxic vanadium species. Developments in the use of DGT devices as a sampling method will also aid in future studies involved in analyzing environmental health and specifically dissolved V species in natural waters. Author Keywords: diffusive gradients in thin-films, dissolved organic matter, fluorescence, mass spectrometry, UV-Vis, vanadium
Comparative Studies in Tropical Epicentres in Southeast Asia
From ca. 800-1400 CE, low-density agrarian states dominated Southeast Asia, their authority emanating from their epicentres at places such as Angkor in Cambodia, Bagan in Myanmar, and Sukhothai in Thailand. These epicentres were the setting for numerous structures, activities, and stakeholders that became integral for the perpetuation of the state. These states and their epicentres declined and collapsed around the same time. As part of a larger project (the Socio-ecological Entanglement in Tropical Societies (SETS Project), the aim of this thesis is to add to our understanding of entanglement, resilience, and collapse in Southeast Asia. Using a relatively new method that combines resilience and entanglement theories, this thesis presents a view of epicentral entanglements and vulnerabilities that eventually contributed to the collapse of these societies. The results indicate that overextended socio-ecological systems and their growing entanglements created a loss of resilience and, when faced with change in these systems, collapse. Author Keywords: Angkor, Bagan, Entanglement Theory, Resilience Theory, Southeast Asia, Sukhothai
Nymphs, Satyrs and Impotent Old Men
British pornographic texts arguing the texts were part of a wider cultural discourse on luxury, criticising the upper echelons of society for their decadent and vice-ridden lifestyles. Pornographic texts consistently portray the elites of Britain as partaking in sexual deviances including lesbianism, sex with dolls, dildos and household objects. The portrayals could be dismissed as tales fabricated for the titillation of the reading audience except that medical texts of the period diagnose the diseases of nymphomania and satyriasis, the rough equivalent of modern sexual addiction, as primarily affecting those of the upper class. Lifestyle was the key to diagnosis; luxurious living was thought to weaken the elite body rendering it vulnerable to excess sexual passions. Therefore, the hyper-sexual elite in pornographic texts reflected the contemporary cultural understandings of lifestyle and physiology. Author Keywords: Britain, culture, eighteenth century, nymphomania, pornography, sexuality
Memorable Movie Watching
Memorable Movie Watching: Viewer Ruminations about Memory in Four Canadian Films and their IMDb User Reviews explores how four Canadian films released in the decade around the turn of the millennium tell stories of memory and remembering, and how User Reviewers writing on the IMDb.com engage with, respond to, and re–remember those narratives filtered through their own remembered personal experiences. It embraces a new form of audience research by analyzing films alongside voluntary viewer contributions in order to bring these viewers’ voices into the conversation about memory in film and specifically Canadian film.Lilies (John Greyson, 1996), The Hanging Garden (Thom Fitzgerald, 1997), Marion Bridge (Wiebke Von Carolsfeld, 2002), and My Winnipeg (Guy Maddin, 2007) are each fiction films that focus on the main character’s deeply personal childhood memories. A textual analysis of the four films reveals trends in how the filmmakers create memory explorations and memory works [works based on memory] in Canadian film. A further textual and thematic analysis of the IMDb’s 117 User Reviews for these four films reveals how viewers engage with what I term memory narratives and the personal memories these films spark. The four films respectively privilege, through narrative and filmic techniques, each protagonist’s telling of remembered childhood events. Yet when User Reviewers of the films comment on the protagonist’s remembered childhood events, they choose to contest them, citing the unreliability of the remembered and of memory itself. User Reviewers interrogate the film narratives against their own personal experience, all the while asserting that there is significance to be found in the process of remembering. For User Reviewers, this process of remembering involves engaging with the film and then writing about their memories of watching the film and its narrative through their own sparked memories. In this process, they dig for significant meaning even though Users rarely articulate that meaning or specify for whom it is meaningful. In their writing, Users do reveal their own thoughts and beliefs about Canadian film, as well as their knowledge of filmmakers, related texts, Canadian locations, and their own childhood and youth experiences. Key words Memory, Remembering, Canadian Film, User generated content, Audience, Viewer, Thom Fitzgerald, John Greyson, Guy Maddin, Wiebke von Carolsfeld Content Warning Please note: the memory stories depicted in these films, discussed in the User Reviews and in this dissertation are extremely disturbing and may be upsetting to the reader. Author Keywords: Audience, Canadian Film, Memory, Social Media, User Generated Content, Viewer
Changes in Forms of Uranium in Anoxic Lake Sediments and Porewaters Near an Abandoned Uranium Mine, Bancroft, Ontario
Soluble uranium (U) has been observed continuously in the porewaters of Bentley Lake, a lake with semi-permanent anoxic sediments, despite the fact that reduced U(IV) is known to be insoluble. To be able to predict the fate and mobility of U that has been deposited in lake sediments, it is very important to understand the factors that determine soluble uranium in anoxic environments. Understanding soluble U species is crucial for predicting its behavior in natural systems as well as for the development of U remediation schemes. To explore the factors affecting soluble U in natural environments, anoxic lake sediments and porewaters were tested using two analytic methods, ICP-MS and ESI-HR-MS. Reduced uranium (U(IV)) can be precipitated as U(IV)-NdF3. Using this method revealed that most of the uranium in porewater is not able to be co-precipitated with NdF3. In addition, UO2+ was found using ESI-HR-MS, showing uranyl ions exist in reduced porewater. However, the UO2+ might be attached to some organic groups rather than present as free ions. Seasonal variation and air exposure experiments on the mobility of U between sediments and porewater were observed to test for changes of the redox state of U as a function of sample collection and storage. The results of this study will contribute to better remediation strategies for U tailings and will help U mining operations in the future. Author Keywords:

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Graduate student theses produced at Trent University. You may also browse theses and dissertations by year, program, or author.

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1973 - 2033
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Format: 2023/03/27

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