The Great Lakes has been impaired by elevated concentrations of contaminants, and different regulatory actions are taken to decrease theses concentrations. Recent research of Dr. Azim suggests a decline in mercury levels in the Lake Erie, and an increase in the Hg concentration in the fish communities. This research is a follow up study to examine whether the contaminant levels are indeed increasing. In the first chapter we evaluate the temporal trends of polychlorinated biphenyls (PCBs) in Lake Erie fish over the last 30 years by conducting the Exponential and Dynamic Linear Modeling analysis. DLM analysis in the chapter two detects the PCB and Hg contaminant trends in a broader range. There is a high variability in two contaminants trends. These patterns may be because of factors such as fish physiological parameters, and the impact of invasive species. The results of my research will contribute to the Toxics Reduction Strategy.

The popularity of Farmers’ markets is on the rise; in Canada there are 425 farmers’ markets, with over 130 in Ontario alone (Feagan, Morris, & Krug, 2004). Farmers’ markets provide high quality, local produce and are often considered an environmentally sustainable food practice (Taxel, 2003; King 2008). United States studies have scrutinized farmers’ markets as exclusionary white spaces that are not equitably accessible, but similar Canadian studies are rare. A case study at the Wychwood Artscape Barns, located in an economically and culturally diverse neighbourhood, in Toronto Ontario has been conducted. Demographics surveys of patrons were compared with existing demographic data; interviews were conducted to discover who shops at the market and for what reasons; results were analyzed using whiteness theory. Results were consistent with U.S. studies – Wychwood Farmers’ Market patrons were white, high income,individuals with university educations; these individuals shop at the market disproportionally to the demographic data.

The Great Lakes has been impaired by elevated concentrations of contaminants, and different regulatory actions are taken to decrease theses concentrations. Recent research of Dr. Azim suggests a decline in mercury levels in the Lake Erie, and an increase in the Hg concentration in the fish communities. This research is a follow up study to examine whether the contaminant levels are indeed increasing. In the first chapter we evaluate the temporal trends of polychlorinated biphenyls (PCBs) in Lake Erie fish over the last 30 years by conducting the Exponential and Dynamic Linear Modeling analysis. DLM analysis in the chapter two detects the PCB and Hg contaminant trends in a broader range. There is a high variability in two contaminants trends. These patterns may be because of factors such as fish physiological parameters, and the impact of invasive species. The results of my research will contribute to the Toxics Reduction Strategy.

The preservative concentration difference in treated wood was investigated to understand the component distribution; a study of different chemical extractions of treated wood waste was carried out and certain reagents were realized to be feasible to the preservative component removal. During fixation, the preservative components redistributed between earlywood and latewood and concentration gradients at depths also developed. Different solvent extractions of CCA treated wood were tested and ion exchange, chelation and metal dissolving were all mechanisms for component extraction. The transition of Cr(III) to Cr(VI) by oxidizing reagents (NaClO and H2O2) can make possible the direct reuse of extracted chemicals as a preservative. Different reaction factors in the oxidant extractions were compared and higher pHs significantly improved the oxidizing capability of the reagents and CCA component removal. Fresh and aged CCA treated wood generally responsed similarly to the oxidant extractions. However, arsenic in aged wood was more difficult to be removed by NaClO, while, H2O2 was more efficient to extract CCA components from aged wood than fresh wood. Monoethanolamine (Mea) efficiently extracted copper (above 90%) from ACQ treated wood and the formation of stable neutral Cu(Mea)2 in sufficient Mea solution is the main mechanism for Mea extraction. Little wood structure degradation occurred during the process. Mea (10%~15%) extraction was fast and the effect of temperature was insignificant. Cu diffusion in the longitudinal direction was the most significant compared to other wood directions. To further promote Mea extraction, repeated extraction (batch-based and column-based) was performed and proved to be more efficient, feasible and economical than one-time extraction. Column-based continuous Mea extraction showed both high Cu removal (up to 99%) and Cu accumulation in the extract. After the preservative treated wood waste is decontaminated significantly, the extract solution can be reused by directly mixing with the preservative treating solution, which is the most straightforward procedure for the recycling of chemicals removed from the preservative treated wood.

Mercury is an environmental contaminant of global concern. The distribution of mercury in freshwater systems is poorly characterized in Mexico, despite widespread contamination from industrial and urban effluents. The land use, geology, and hydrology of the Lake Zapotlán basin, Mexico are conducive to the delivery of elevated mercury in water to the lake due to untreated wastewater discharge, deforestation, and local volcanic history. To assess a mercury exposure risk to fish consumers, the concentrations of total Hg (THg) in water inputs, surface waters, sediments, and the commercial catch of tilapia and carp were investigated. Results indicate that despite high particle-bound inputs of THg to the lake in runoff and wastewater, THg in sediments and surface waters were low. Dense Typha latifolia dominated wetlands are believed to retain THg inflow from water inputs. Concentrations of THg in tilapia and carp were low, suggesting low mercury bioavailability in this system.

Organizational theory can assist in better understanding how changes made in clinical practice can be sustained in healthcare organizations. Organizational learning and knowledge transfer theories were used to develop and test a theoretical model, “Sustaining in Memory” (SIM) model, to explore how organizations disperse or distribute newly transferred knowledge in knowledge reservoirs situated in the organization. Three hypotheses were generated from the theoretical model and tested with data from a cross sectional postal survey of 148 patient/resident care units in one large Canadian province where a CPG on prevention of falls was widely disseminated. Findings confirmed that fall prevention practice knowledge was transferred and embedded in all six knowledge reservoirs; however, there were three specific knowledge reservoirs that were found to be significant predictors of perceived CPG adherence (activities consistent with the CPG recommendations). These were staff, policy and role expectation knowledge reservoirs. There was variation in the adherence to the eight CPG recommendations with greater adherence to recommendations that were mandatory. Additionally, findings showed that the relationship between staff knowledge reservoir and CPG adherence was the only relationship moderated by the practices that helped to prevent/address knowledge loss through various activities designed for reviewing and updating practice knowledge. Interestingly, although CPG adherence was reported significantly greater in LTC resident care units, its association with patient outcomes was much weaker than in hospital patient care units. Hospital units had significantly greater correlation between perceived CPG adherence and all four of the falls prevention outcomes reported by study participants. Lastly, quality management culture as managed by senior leaders in the organization was also found to be a significant predicator of adherence to the CPG. The research study validated key assumptions made in the theoretical model while helping to clarify the distinct influence of different knowledge reservoirs. The SIM model provided an alternate perspective within which to study knowledge transfer and sustainability of clinical practices and has potential to apply to other change initiatives. This study answered the call for greater theoretically driven studies of CPG implementation as well as attention on the organizational influences of CPG implementation and sustainability.

A study was undertaken to characterize two dynamic fuel types not included in the Canadian Forest Fire Behaviour Prediction System: forested bogs and blowdown. Fuel load and structure were measured at ten forested bog sites in central Alberta along a 108 year post-fire chronosequence. Canopy bulk density increased following a sigmoidal curve between 0.00 and 0.54 kg•m-3. Crown fire potential was modeled using a general crown fire behaviour model and found to follow a similar sigmoidal pattern increasing with time-since-fire. Blowdown fuel loads were measured at six sites in northwestern Ontario and ranged from 13.4 to 18.9 kg•m-2. Elevated fine blowdown fuels were found to have faster reaction times and dry more rapidly than predicted by the Fine Fuel Moisture Code. Detailed observations were also made of fire behaviour in blowdown fuels

A study was undertaken to characterize two dynamic fuel types not included in the Canadian Forest Fire Behaviour Prediction System: forested bogs and blowdown. Fuel load and structure were measured at ten forested bog sites in central Alberta along a 108 year post-fire chronosequence. Canopy bulk density increased following a sigmoidal curve between 0.00 and 0.54 kg•m-3. Crown fire potential was modeled using a general crown fire behaviour model and found to follow a similar sigmoidal pattern increasing with time-since-fire. Blowdown fuel loads were measured at six sites in northwestern Ontario and ranged from 13.4 to 18.9 kg•m-2. Elevated fine blowdown fuels were found to have faster reaction times and dry more rapidly than predicted by the Fine Fuel Moisture Code. Detailed observations were also made of fire behaviour in blowdown fuels

Although many commercial chemicals can dissociate, the study of the biological and environmental fate of ionogenic organic chemicals (IOCs) is still in its infancy. Uptake of the veterinary drug diclofenac in vultures and cattle was successfully simulated with a newly developed physiologically-based pharmacokinetic model for IOCs, lending credence to diclofenac’s proposed role in South Asian vulture population declines. Proteins and phospholipids rather than total lipids control the tissue distribution of diclofenac. A method was developed to simultaneously extract neutral and acidic pesticides and benzotriazoles from water samples with recoveries ranging 70-100%. This method was applied to samples from a laboratory calibration experiment of the Polar Organic Chemical Integrative Sampler. The sampler had higher uptake for neutral and acidic pesticides when filled with triphasic sorbent admixture and OASIS MAS sorbent, respectively. While either sorbent can also be applied for methylated benzotriazoles, neither is capable of quantitatively sampling all three compound groups.

Methods of chemical hazard ranking and toxic impact assessment estimate fate and toxicity assuming the chemical exists in dissolved and particulate phases and, for metals, that all dissolved species are equally bioavailable. This treatment of metals, similar to organic chemicals, introduced a significant error in their estimates of hazard ranking since metal bioavailability and ecotoxicity are related to truly dissolved phase and specifically free metal ion within it. My thesis addressed this concern by developing a new method that introduced Bioavailability Factor (BF) to the calculation of Comparative Toxicity Potentials (CTPs) for hazard ranking of chemicals; also known as Characterization Factors for use in Life Cycle Impact Assessment (LCIA). First, the metal speciation/complexation was incorporated into fate calculations by loosely coupling commercial geochemical metal speciation model, WHAM, with a multimedia fate model, USEtoxTM, which is originally designed to calculate CTPs for organic chemicals. Second, Biotic Ligand Model (BLM) was used to calculate the bioavailability-corrected adverse toxic effects of metals. This new method was applied to assess the implications of choosing environmental characteristics, notably freshwater chemistry, by calculating BFs and CTPs of several cationic metals (e.g., Cd, Cu, Co, Pb, Ni and Zn) using 12 European, 24 Canadian ecoregions, several distinct freshwater-types selected from large river and lake systems world-wide. The newly estimated metal CTPs (i.e., ecotoxicity potentials) are up to ~1000 times lower than previous values used in LCIA. Notably the model results showed that the absolute values of CTPs, and their relative ranking amongst chemicals, are a product of the characteristics of a receiving environment. Hence it is crucial to select a generic freshwater archetype on which this analysis should be based. Finally, the new model framework was extended to apply within the Unit World Model (UWM) framework to estimate critical loads (CLs) of cationic metals to surface aquatic systems.