Scientists factoring in ‘indirect pathways’ of pollution discover significantly higher emission of carcinogens
– Lauren McCauley, staff writer
Using predictive computer models, University of Toronto Environmental Chemistry professor Frank Wania and his PhD candidate Abha Parajulee found that officially reported emissions of the atmospheric pollutants known as polycyclic aromatic hydrocarbons (PAHs) do not factor in “indirect pathways” of pollution, such as those which blow off mining sites or evaporate from tailings ponds.
The scientists report that, according to their models, evaporation from tailings ponds—lakes of polluted byproduct created through tar sands processing—may actually introduce more potentially carcinogenic PAHs into the atmosphere than direct emissions.
Further, the higher levels of PAHs recorded by the models are consistent with previous pollution samples taken from in and around the Athabasca Oil Sands Region, throwing into question industry-reported estimates which did not take these alternate “pathways” into account.
According to the findings, actual levels of emissions into the air may be as much as two to three orders-of-magnitude greater—or one hundred to one thousand times greater—than previously estimated.
According to the study,
[M]odeling suggests that the emissions to air required to explain measured concentrations of [the sample PAHs] in the atmosphere of the Athabasca Oil Sands Region are two to three orders-of-magnitude larger than those reported as direct emissions to air by the National Pollutant Release Inventory and as total emissions to air by the Environmental Impact Assessment (EIA) report.
“It was shocking to me to understand that current environmental impact assessments do not take this into account at all,” Jonathan Martin, an associate professor at the University of Alberta department of environmental toxicology who reviewed the research, told Agence France-Presse.
“It just shows how little we know,” Martin added.
“When dealing with chemicals that have the potential to harm people and animals, it is vital that we have a good understanding of how, and how much they are entering the environment,” said Parajulee.
Wania adds that current estimates are “very likely too low,” and that “the potential risks [of tar sands mining] to humans and wildlife may also have been underestimated.”
As environmental reporter Andrew Nikiforuk notes, ahead of the publication there had been a recorded increase in contamination levels of wildlife downstream from the mining region:
[The University of Toronto] 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.”
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