Its About Science Denial...

Alberta's Tar Sands   Photograph by: © Todd Korol / Reuters, Reuters

So nobody wants to believe anything bad about the tar sands in northern Alberta. Then David Schindler  does a little checking and figures out that mining the bitumen and running it through an upgrader dumps various PAHs (polycyclic aromatic hydrocarbons) around the area. Now, this beiung northern Alberta, the area around the upgraders is covered with snow about nineteen months a year (okay, that might be a slight exageration) and the various bad things fall on the snow. Every once in a while (about once a year) all the snow melts and is carried away in the Athabasca River. The quick melting of the snow causes a pulse of pollutants to hit the river's ecosystem at a particularly vulnerable time of year.
Much denial and mocking ensues--except from the local First Nations people who have noticed a higher- than-statistically-normal number of rather nasty cancers in their (downstream) population. Under tremendous international pressure, the Oilberta government agrees that yes, maybe some research should be done in the area. The government has been pushing for development of the tar sands since the seventies, but has never thought to do a baseline pollution study--even though various people and groups have been suggesting, asking, and demanding one for forty years. They still haven't, but are allowing a few studies in the area to go ahead.
So the Edmonton Journal is reporting on one of these studies:

Federal scientists have uncovered evidence that contaminants wafting out Alberta’s oilsands operations are collecting on the bottom of remote lakes up to 100 kilometres away.
The chemical “legacy” in the lake sediments indicates that oilsands pollution is travelling further than expected and has been for decades.
“The footprint of the deposition is potentially larger than we might have anticipated,” says Derek Muir, a senior Environment Canada scientist, who will present the findings Wednesday at an international toxicology conference in the U.S. where the oilsands are a hot topic.
A team led by federal scientist Jane Kirk, also of Environment Canada, will report that snow within 50 kilometres of oilsands operations is contaminated with a long list of  “priority pollutants” including a neurotoxin that “bioaccumulates” in food webs.
Kirk’s colleague Joanne Parrott will report that melt water from snow collected near oilsand plants is toxic to newly hatched minnows in the lab.
But perhaps the most dramatic findings is that pollutants called polycyclic aromatic hydrocarbons, or PAHs, are building up in lake sediments up to 100 kilometres from the oilsands operations.
“That means the footprint is four times bigger than we found,” says David Schindler, an aquatic scientist at the University of Alberta. He and his colleague Erin Kelly made headlines in 2010 when they reported that airborne heavy metals and other pollutants from oilsands operations were contaminating the landscape up to 50 kilometres away.

So, as usual in Oilberta, the reality is radically different (and much worse) than the provincial government will ever acknowledge.