I would make a couple of comments. One is that most of the geologists who have studied the area say there is no such thing as an impermeable layer, and that in fact there is seepage. It will take place either more quickly or more slowly, depending on the permeability, but it will take place. The fact that there are already naphthenic acids, which are only produced through the oil sands mining bitumen processing operation, in the sediments in the river would suggest that the stuff isn't staying in the groundwater.
Also, if you read the Alberta Research Council's analysis, and look at what is done in several environmental assessments—I don't know whether that's all, as I only looked at two—the concern for groundwater has been a very local one in the environmental assessments. What the Alberta Research Council is saying is that we should be looking at the groundwater flow on a regional basis and what's happening regionally.
So I'm not convinced that the contamination in the groundwater isn't seeping into the river.