Environmental health

Cadmium is a toxic metal that has detrimental effects on blood vessel development and function. To examine the effect of varying concentrations of cadmium on angiogenesis, two in vitro assays were used. First, developing yolk sac blood vessels were studied in gestation day 8 mouse embryos exposed to medium alone, 1.25, or 1.75 μM cadmium chloride (CdCl2). Embryos exposed to 1.25 μM cadmium experienced a significant increase in the number of vessels formed; however, they were smaller in size. Vessel morphology and signalling pathways were also investigated using the mouse aortic ring assay, with exposures of 0.0, 0.5, 1.0, 5.0, or 10.0 μM CdCl2. Samples exposed to 10 μM experienced a significant increase in vessel length. However, no significant differences in phosphorylated PTEN and AKT were observed. The results of this study suggest that low levels of cadmium may disrupt angiogenesis, particularly the development of the embryonic vasculature in the yolk sac.

Author Keywords: Angiogenesis, Cadmium, Embryonic Development, Teratogenicity, Vascular Development, Vasculogenesis

Small scale farming at the homestead or hobby farm scale provides opportunities for members of the public to visit farms, see livestock, and engage directly with how their food is produced. This scale is often dismissed as or minor importance, yet the biosecurity of larger farms makes these small farms often the only ones that the public can visit. My research explores whether communities want these direct connections with agriculture, and if this provides understanding of the interconnection of farming ecosystems. As a small scale egg producer, I first provide a personal autoethnography of my own operation. I then examine my customers attitudes toward my produce and farm, and analyse interview of other local producers and community members.

Author Keywords: Connectivity, Diversity, Family farming, Homesteading, Small-scale agriculture, Sustainable agriculture

This thesis develops an Long Short-Term Memory (LSTM) neural network model to assess the relationship between ambient air pollutant exposure and public health risks, accommodating both linear and nonlinear associations with distributed lags.The research makes three key contributions. First, Maximal Information Coefficient (MIC) methods identify the most relevant air pollutants and their associations with health outcomes. Second, an LSTM model extracts temporally dependent features from exposure series to estimate health impacts. Finally, the model's potential in air pollution epidemiology is explored using Local Interpretable Model-Agnostic Explanations (LIME) to interpret the exposure-health response relationship.

Author Keywords: air pollution epidemiology, Deep Learning, explainable AI, Long Short-Term Memory, Maximal Information Coefficient, public health assessmen

Climate change is a global challenge with profound environmental, health, andsocio-economic implications. Canada's diverse geography offers a unique lens to study localized climate trends. This thesis models and clusters climate variables, focusing on temperature trends, using Bayesian hierarchical models and clustering techniques to uncover regional patterns and health impacts. Three decades of hourly temperature data from the Meteorological Service of Canada were split into 18 annual parts to capture seasonal variations. Metrics like mean, minimum, and extreme temperatures were analyzed. Bayesian models revealed regional variability, with examples of British Columbia and the Northern regions exhibiting notable trends. Clustering identified regional dependencies and linked temperature trends with morbidity and mortality risks from air pollutants (PM2.5, O3). Summer risks stemmed from O3, while winter risks were PM2.5 driven. Findings highlight the need for region-specific strategies, offering actionable insights for policy makers addressing climate-health linkages.

Author Keywords: Bayesian models, Climate change, Clustering, Temperature Trends, Time Series

Cadmium is a toxic metal that has detrimental effects on blood vessel development and function. To examine the effect of varying concentrations of cadmium on angiogenesis, two in vitro assays were used. First, developing yolk sac blood vessels were studied in gestation day 8 mouse embryos exposed to medium alone, 1.25, or 1.75 μM cadmium chloride (CdCl2). Embryos exposed to 1.25 μM cadmium experienced a significant increase in the number of vessels formed; however, they were smaller in size. Vessel morphology and signalling pathways were also investigated using the mouse aortic ring assay, with exposures of 0.0, 0.5, 1.0, 5.0, or 10.0 μM CdCl2. Samples exposed to 10 μM experienced a significant increase in vessel length. However, no significant differences in phosphorylated PTEN and AKT were observed. The results of this study suggest that low levels of cadmium may disrupt angiogenesis, particularly the development of the embryonic vasculature in the yolk sac.

Author Keywords: Angiogenesis, Cadmium, Embryonic Development, Teratogenicity, Vascular Development, Vasculogenesis

Children may be spending less time outdoors in nature than in previous generations, with one potential reason being parents in their role as 'gatekeepers' to the outdoors. This study investigated how families are spending their time during the COVID-19 pandemic, and how parents may influence children's outdoor nature experiences. Parents (N = 121) from across Canada completed measures related to their family's activities as well as their own connection with nature, attitudes about nature, and childhood nature contact. Results suggest that having easy access to nature, a greater connection with nature, believing in the importance of outdoor experiences, and doing outdoor activities in childhood may be associated with more current family time outside in nature. By understanding the reasons behind parental decisions regarding where and how families spend time outside, strategies can be developed to help parents increase their children's nature time in the future.

Author Keywords: children, family, nature, nature-relatedness, outdoors, parents

Addressing the issue of food insecurity effectively within a region in a way where interventions reflect the variability of food insecurity levels across subgroups of the population is important. It is a unique challenge and requires specific data. This study took in this direction by conducting an exploratory statistical analysis of a community-representative dataset of Inuit Seniors' food (in)security. The analysis was theoretically sensitive as well as knowledge-user-directed.Results show that 52.7% of all Seniors in Nain and Hopedale, Nunatsiavut, are food insecure, and that food (in)security is associated with age group, education status, health status, mobility status and household financial situation. Further, younger Seniors aged 55-64 are more likely to be food insecure than their older peers. This study is among the first to provide an analysis of quantitative associations between variables that characterize food (in)security among a specific subgroup in the Inuit population.

Author Keywords: Arctic, Case study, Food security, Inuit health, Seniors, Vulnerability

Plastic pollution is a growing concern, owing to its durability, ubiquity, and potential health impacts. The overall objective of this study was to assess the abundance and distribution of microplastics within Lake Scugog catchment, Ontario. This was fulfilled through two tasks (i) the development of a microplastic particle budget for the lake catchment, and (ii) the determination of the dry deposition of atmospheric microplastics in Port Perry, Ontario. The total input of microplastics into Lake Scugog (atmospheric deposition and stream inflow) was 2491 x106 mp/day, while the output (lake outflow and sedimentation) was 1761 x106 mp/day, suggesting that 29% of inputs were retained in the lake. The dry deposition of microplastics in Port Perry was 1257 mp/m2/day, which was high when compared to bulk deposition (37 mp/m2/day) in the same area. By quantifying the major pathways of microplastics better management techniques can be implemented.

Author Keywords: Catchment, Dry Deposition, Microplastics, Ontario, Particle Budget, Plastic pollution

This thesis sought to explore and evaluate perceptions of food needs and the role of a community freezer in addressing those needs, among Inuit in Hopedale, Nunatsiavut (Northern Labrador). Research was carried out through an exploratory sequential mixed-methods design. Phase 1 employed qualitative interviews with community members in Hopedale to explore the perceptions of food needs from an Inuit perspective. Results from Phase 1 identified a series personal, physical, cultural, and social food needs that informed the development of a series of questions that were integrated into a community-wide survey that was implemented in Phase 2. Results from Phase 2 identified a series of cultural, household and individual characteristics that significantly impact perceived ability to meet needs among community members in Hopedale. Findings from this research contribute to our understanding of food needs, and may potentially influence estimates of levels of needs that are protected in Inuit land claims, and inform the development or improvement of community methods for food support.

Author Keywords: Food Needs, Food Programs, Food Security, Indigenous, Inuit, Mixed-Methods

The potential impacts of domestic wastewater (DWW) on the source of drinking water for the M'Chigeeng First Nation were monitored as part of the development of a Source Water Protection plan. During a period of continuous overflow of the Gaaming Wastewater Lagoon serving the community, the chemical tracers, caffeine and sucralose were tracked in West Bay with Passive Organic Chemical Integrative Samplers (POCIS). From the results, we speculated that DWI impacts could have been from three possible DWW sources. POCIS deployed above and below the thermocline indicated a higher mean sucralose concentration of 2.52 ± 1.83 ng/L in the hypolimnion of West Bay relative to mean epilimnetic sucralose concentrations of 0.56 ± 0.02 ng/L, suggesting possible wastewater percolation with an estimated time of travel of 61.5 days. Microbial loads of 200 CFU/100 ml E. coli from the lagoon overflow into Mill Creek decreased to 60 CFU/100 ml before entering West Bay. West Bay's wastewater assimilative capacity met Provincial Water Quality Objectives in the epilimnion and hypolimnion except for dissolved oxygen in the hypolimnion at 4.16 ± 1.86 mg/L, which is a threat to the onset of hypoxia for fish (i.e. <5 mg/L). Assimilative capacity results support a Fall lagoon discharge.

Author Keywords: caffeine, drinking water, Passive Organic Chemical Integrative Samplers (POCIS), sucralose, thermocline, wastewater