A new study has found that certain types of chemical pollutants emitted by Canada's oilsands tailing ponds have gone underreported for years.
Using a computer simulation model, two University of Toronto scientists also found the pollutants in question are blowing off mine sites or evaporating from nearly two dozen impoundments containing a billion cubic metres of toxic waste.
Two of the dikes holding the mining waste products are among the largest man-made dams in the world.
The pollutants are three polycyclic aromatic hydrocarbons (PAH), a class of chemicals that includes a variety of cancer makers and that have become a major contaminant of waterways in the region.
When the scientists discovered that industry reporting on estimates of PAH pollutants in the oilsands were too low to explain the levels of PAHs now being found up to 95 kilometres away, they realized that industry had not been reporting emissions from the tailing ponds.
The scientists also found that PAHs evaporating from the lakes of mining waste were likely a greater contributor of pollution to the atmosphere in the region than emissions directly released into the air by industry.
In a companion essay to the study published in the Proceedings of the National Academy of Sciences (PNAS), water ecologist David Schindler explained the significance of the findings by noting "that by ignoring emissions from tailings ponds, the annual release of polycyclic aromatic compounds from the oilsands industry have been underestimated by as much as two orders-of-magnitude."
"Unfortunately, both the official National Pollutant Release Inventory and all previous environmental impact assessments for oilsands expansion in the area have relied on the underestimated values," added Schindler.
Each year, oilsands tailings ponds, which represent a $20-billion clean-up liability for the province of Alberta, increase in area and volume, despite 2009 regulations that were supposed to contain their spread due to public concerns about leaks and bird deaths.
In 2013, the Alberta Energy Regulator (formerly the Energy Resources Conservation Board) admitted that the industry had failed to meet the standards to contain the production of toxic waste: "Given the issues that industry has encountered, the ERCB does not believe that it would be appropriate to enforce compliance measures at this time," it added in a report assessing tailings management.
According to the Pembina Institute, the oilsands mining industry could submerge an area the size of New York's Central Park in 3.4 meters of toxic waste every month by 2022.
The pollutant modelling study follows reports of growing mercury pollution around the oilseeds made by Environment Canada scientists at a conference of the Society of Environmental Toxicology and Chemistry in Nashville last November.
Scientists reported that a 19,000 square-kilometre area around the project is now "currently impacted by airborne Hg (mercury) emissions originating from oilsands developments."
Mercury levels in birds downstream of the project have been increasing in several species, and now exceed toxic thresholds for Caspian Terns.
Award-winning journalist Andrew Nikiforuk writes about energy for The Tyee and others.