Laboratory Investigation of Diluted Bitumen Trapping and Dissolution in Gravel

The Canadian economy is largely dependent on the distribution of large volumes of oil to domestic and international markets by a long network of pipelines. Unfortunately, accidents occur, and oil can leak or spill from these pipelines before it reaches its destination. Of particular concern are the long-term consequences of oil spills in freshwater, which include sinking of oil in water and the contamination of sensitive areas, such as where fish (e.g., salmon) deposit their eggs in gravel-dominated river sediments. There is a knowledge gap regarding the fate and behaviour of oil in river sediment. To this end, this study aimed at finding the potential for diluted bitumen (dilbit) oil to become trapped in gravel and to transfer hydrocarbons into water by dissolution, which are harmful to aquatic life. Two sets of laboratory experiments were conducted to simulate conditions of an oil spill on an exposed bank or in shallow water. In the first set, by conducting capillary pressure-saturation (Pc-Sw) experiments it was found that dilbit can enter gravel pores without much resistance and approximately 14% of the pore volume can be occupied by discontinuous single or multipore blobs of dilbit following imbibition of water. Air-water Pc-Sw experiments done in laboratory 1-D columns required gravity correction and could be successfully scaled to predict dilbit-water Pc-Sw curves, except for the trapped amount of dilbit. Trapped dilbit constituents can be dissolved into the water flowing through gravel pores (hyporheic flow) at different velocities. In the second set, dissolution experiments suggested that for the duration of the test, hydrocarbons that cause acute toxicity dissolve rapidly, likely resulting in a decrease in their effective solubility. However, dilbit saturation changed only <2% within that time. Chronically toxic PAH compounds were also detected in the effluent water. The total concentration of all detected PAHs and alkylPAHs exceeded the threshold literature value to protect early-life stage fish. Observations of decreased concentrations with increased aqueous velocities as well as less than equilibrium concentrations indicated that the mass transfer was rate-limited. A correlation was developed for the mass transfer rate coefficient to understand the mass transfer behaviour beyond the conditions used in the experiments, which had a Reynolds number exponent similar to the studies of NAPL dissolution in groundwater.

Performance Information and Innovation in the Canadian Government (Working Paper 43)

The presentation made at the conference addressed the issue of linkages between performance information and innovation within the Canadian federal government1. This is a three‐part paper prepared as background to that presentation. • Part I provides an overview of three main sources of performance information - results-based systems, program evaluation, and centrally driven review exercises – and reviews the Canadian experience with them. • Part II identifies and discusses a number of innovation issues that are common to the literature reviewed for this paper. • Part III examines actual and potential linkages between innovation and performance information. This section suggests that innovation in the Canadian federal government tends to cluster into two groups: smaller initiatives driven by staff or middle management; and much larger projects involving major programs, whole departments or whole-of-government. Readily available data on smaller innovation projects is skimpy but suggests that performance information does not play a major role in stimulating these initiatives. In contrast, two of the examples of large-scale innovation show that performance information plays a critical role at all stages. The paper concludes by supporting the contention of others writing on this topic: that more research is needed on innovation, particularly on its link to performance information. In that context, other conclusions drawn in this paper are tentative but suggest that the quality of performance information is as important for innovation as it is for performance management. However, innovation is likely to require its own particular performance information that may not be generated on a routine basis for purposes of performance management, particularly in the early stages of innovation. And, while the availability of performance information can be an important success factor in innovation, it does not stand alone. The commonality of a number of other factors identified in the literature surveyed for this paper strongly suggests that equal if not greater priority needs to be given to attenuating factors that inhibit innovation and to nurturing incentives.