I can probably address that. I've been involved in some of that work for 20 years.
There are actually several pulp and paper mills upstream on the Athabasca, but over the past 20 years they have really cleaned up their act. The one at Hinton, for example, spewed huge amounts of dioxins and furans into the river in the early years of its operation. I think the watershed was when the Alberta-Pacific mill, which is near Athabasca, several hundred kilometres above the area we're talking about, in a dispute in the early nineties that I was a part of, produced a process that eliminated dioxin from effluents. Since that time, dioxins are no longer a part of the effluents from pulp mills. There are still some organic compounds and so forth. One source of worry, actually the source of worry that drove the northern river basins study of the 1990s, has been eliminated.
I think the development in Fort McMurray is probably contributing several of the toxic trace metals. For example, copper is released from wearing brake shoes, and nickel and cadmium and mercury are associated with other parts of automobiles, and zinc from wearing tires. In many communities that's washed from the streets into effluents and into the nearest watercourse. I'm sure, as Fort McMurray grows, that will become an increasing problem. But right now, even at 80,000 people, I'd say it's a fairly small contribution to a river the size of the Athabasca.