University of Toronto Scarborough Environmental chemistry professor Frank Wania, one of the authors, found that modelling assessments used to gauge emissions of a group of atmospheric pollutants known as polycyclic aromatic hydrocarbons (PAHs) are not comprehensive.
PAHs, many of which are highly carcinogenic, are released when petroleum is extracted from the oil sands. Environmental Impact Assessments focus almost solely on PAHs that are released directly into the atmosphere, and those levels are deemed to fall within acceptable regulatory limits.
But the model used in Wania’s study looked also at other “indirect pathways” for the release of PAHs that had not been looked at closely.
Evaporation from tailings ponds, for example, “may actually introduce more PAHs into the atmosphere than direct emissions”, the researchers said in a statement.
“Tailings ponds are not the end of the journey for many of the pollutants they contain. Some PAHs are volatile, meaning they escape into the air much more than many people think,” said Abha Parajulee, another author of the study.
They said their models that account for tailings emissions suggest higher levels of PAHs that “are consistent with what has actually been measured in samples taken from areas near and in the Athabasca oil sands region”.
The researchers called for better monitoring data and emissions information in order to understand the true environmental impact of the oil sands.
“Our study implies that PAH concentrations in air, water, and food, that are estimated as part of environmental impact assessments of oil sands mining operations are very likely too low,” Wania said. “Therefore the potential risks to humans and wildlife may also have been underestimated.”
The results of the study were published in the Proceedings of the National Academy of Science this week.
*Luke Johnson – Upstreamonline