A new comprehensive modelling assessment of contamination in the Athabasca Oil Sands Region indicates that officially reported emissions of certain highly hazardous air pollutants have been greatly underestimated.
The results of the assessment, which was carried out by University of Toronto Scarborough Environmental Chemistry professor Frank Wania and his PhD candidate Abha Parajulee, were published in the Proceedings of the National Academy of Science on Monday, Feb. 3 2014. The study constitutes the most comprehensive such model that has been done for the Oil Sands Region.
The team modelled emissions of a group of atmospheric pollutants known as polycyclic aromatic hydrocarbons (PAHs). Many PAHs are highly carcinogenic. Children born from women who were exposed to PAHs while pregnant may have lower IQs, a higher risk of asthma and other issues.
"When dealing with chemicals that have such great potential to harm people and animals, it is absolutely vital that we truly understand how, and how much they are being released into the environment," said Parajulee, the lead author of the paper.
PAHs are produced during the process of extracting petroleum from the oil sands. Previous models have assessed only the PAHs that are released directly into the atmosphere during extraction. These numbers tend to fall within acceptable regulatory levels.
Parajulee's model takes into account other indirect pathways for the release of PAHs that haven't been assessed before. For instance, he found that evaporation from tailing ponds -- lakes of polluted water also created through oil extraction -- may actually introduce more PAHs into the atmosphere than direct emissions.
"Tailing ponds are not the end of the journey for the pollutants they contain. PAHs are highly volatile, meaning they escape into the air much more than many people think," says Parajulee.
The higher levels of PAHs the UTSC scientists' model predicts are consistent with what have actually been measured in samples taken from areas near and in the Athabasca Oil Sands Region.
Parajulee and Wania's model also factors in additional PAHs that are released during the transport and storage of other waste materials from oil sands operations.
The pair of researchers modeled only three types of PAHs, which they believe are representative of many other types of air pollutant. Still, they say, their model indicates better monitoring data and emissions information could improve our understanding of the environmental impact of the oil sands even further.
"We need to take a holistic approach that includes both modelling and monitoring," says Wania. "This is the single most powerful way to inform public policy and private management strategies for the region."
By Patchen Barss