Bitumen extraction in the Athabasca oil sands in Alberta releases metals to the region. In this study, I performed an uptake-elimination experiment with wood frog tadpoles (Lithobates sylvaticus) to determine the bioaccumulation potential of metals from exposure to MacKay River sediment, an area affected by oil sands contamination, and to uncontaminated reference sediment. Wood frog tadpoles, Gosner stages 28-32, were exposed to two sediments: (1) MacKay River sediment that is enriched in petrogenic hydrocarbons from natural and anthropogenic sources; and (2) an uncontaminated reference sediment. Tadpole exposures to sediments lasted 4 days, followed by a depuration phase for an additional 4 days where tadpoles were allowed to eliminate excess metals from their bodies. The metal concentrations at various time points during the uptake and elimination phases were determined in order to define toxicokinetic parameters, such as uptake and elimination first order rate constants, accumulation by ingestion, and assimilation efficiencies for specific metals. It was determined that tadpoles exposed to the MacKay sediment had higher concentrations of Al, Co, Cu, Cr, Mg, Ni, Pb, V, and Zn throughout the uptake phase of the study compared to tadpoles exposed to reference sediment. We also observed little to no decrease in concentrations of Al, Co, Cu, Cr, Mg, Ni, Pb, V, and Zn throughout the elimination phase of the study. In addition, biota-sediment accumulation factors (BSAF) revealed that Cu, Zn, Cr, and V had among the highest bioaccumulation potential in our trials. The experiment was subsequently repeated by preventing direct contact of the tadpoles to sediment with a screen, exposing tadpoles only to metals in water. By comparing tadpole exposures to metals from ‘aqueous’ and ‘aqueous +sediment’ in separate trials, and by tracking sediment ingestion rates, I am able to show that sediment ingestion constitutes the primary source of metal bioaccumulation by tadpoles. Not only were metal concentrations higher in tadpoles that were ingesting sediment, but they also had greater metal uptake rates compared to tadpoles that were only exposed to contaminated water. It was also determined that assimilation efficiencies were higher in tadpoles exposed to reference sediment compared to ones exposed to MacKay River sediment. Using toxicokinetic parameters defined by the uptake-elimination experiment, I developed a computational model using STELLATM system dynamics software to accurately estimate first order uptake and depuration rate constants for metals in exposed aquatic animals. The model estimated metal uptake and depuration kinetics with a mean relative error of 2.25 ± 0.93 % (±SE, n=9) for the uptake study and 2.53 ± 2.61 % (±SE, n=9) for the depuration study. With increased oil-sands production anticipated, we recommend continued monitoring of contaminants from oil-sands for the purpose of understanding the potential risks they may have on northern Alberta’s ecosystems.

In an ever-changing world of work Absa, as a business, is faced with various challenges including the continuous development of skills. Due to technological advancements, eLearning can provide a mechanism to rapidly build the required strategic and tactical skills that the organisation needs. This study explored the challenge of articulating the contribution of eLearning to business performance in an unbounded way. The study focused on the creation of knowledge about how the contribution of eLearning to business performance can be improved. In the process of knowledge creation, the study focused on identifying the point of value creation between Business and an eLearning intervention. This point of value creation can be seen as a leverage point. Systems Thinking was implemented as an approach in order to identify the leverage point. The following research objectives were defined: · To identify the driver problem that prevents eLearning from improving business performance. · To design the systems dynamic model that represents the driver problem. · To identify the leverage point within the systems dynamic model. · To reflect on the effect that the behaviour of the individuals, participating in the research process, has on the research inquiry. The sample of 28 focus group participants was selected from two specific divisions of Absa – the eChannels: Contact Centre and the Learning and Development Department. This sample consisted of Operational Management, Team Leaders, Contact Centre Consultants and learning design experts. Executive Management was excluded from the focus groups, but was included in the process as verifiers. This created an opportunity for Executive Management to voice their opinions. The results of the study indicate that the leverage point for successful contribution of eLearning to business performance is … A shared mental model of expectations between the participating stakeholders. Once Business and the Learning and Development Department start going through the constructive cycle of the systems dynamic model repeatedly, they will continuously build the shared mental model of expectations. This cycle will also build on the: 1) Level of visible support of the line managers; 2) Level of clarity of business needs to all relevant stakeholders; 3) Number of requests from business for eLearning opportunities; and 4) Level of awareness and understanding of appropriate eLearning interventions per target population. The effect of the positive reinforcement of the recurring cycle will ensure that eLearning continuously contributes to business performance. During the study the effect of the research process on the focus group participants as well as the effect of the focus group participants on the research process was also accounted for. Observers reflected on the behaviour of the focus group participants and found that their opinions and thought processes influenced the outcome of the study. The focus group participants felt that they had learnt something new, that the tasks set to the groups was clear and that the topics they had learnt most about were ‘systems thinking’ followed by the ’ relationship between eLearning and business performance’. Copyright / Thesis (PhD (Curriculum Studies))--University of Pretoria, 2004. / Curriculum Studies / unrestricted