PRELIMINARY COMPARISONS OF DILUTED BITUMEN WITH CONVENTIONAL CRUDE IN SIMULATED SHALLOW GROUNDWATER SPILLS

There has been an increase in crude oil production in Canada, with much of it produced from Alberta’s oil sands. Oil sands crude is extracted as bitumen, which has a much higher viscosity than conventional crude. The bitumen is diluted with lighter hydrocarbons to reduce the viscosity to allow for pipeline transport. Given some high-profile crude oil spills in recent years, including the spill to the Kalamazoo River in 2010 and the 2013 Lac-Mégantic rail disaster, there has been increased public concern about the safety and potential environmental impacts of crude oil transportation. Given that some organic compounds present within the oil partition to the aqueous phase, one aspect of concern relates to the potential impacts of a spill of diluted bitumen on groundwater resources.

In this study, we conducted groundwater tank experiments to compare the potential impact of a spill from a pipeline of diluted bitumen with a spill of a conventional crude oil. The current research has focused on trying to simulate a spill occurring below the water table. To date, research suggests that water that has interacted with conventional crude will result in higher dissolved concentrations of organic contaminants. The water interacting with conventional crude has nearly double the concentrations of ethylbenzene, xylenes and toluene compared to the diluted bitumen experiment. Concentrations of benzene were similar in both experiments. Stable carbon isotope analysis (δ¹³C) of the bulk dissolved organic carbon (DOC) fraction as well as compound-specific isotope analysis of benzene and toluene are also being carried out to further study the dissolved organics in water. This presentation will include results to date.