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Posts Tagged ‘polycyclic aromatic hydrocarbons’

Wednesday, February 5, 2014 @ 10:02 AM gHale

Emissions of certain hazardous air pollutants are underestimated in the Athabasca Oil Sands Region, according to a new comprehensive modeling assessment of contamination.

The team, led by University of Toronto Scarborough Environmental Chemistry professor Frank Wania and his PhD candidate Abha Parajulee, used a model to assess the plausibility of reported emissions of a group of atmospheric pollutants known as polycyclic aromatic hydrocarbons (PAHs). Many PAHs are highly carcinogenic. The study constitutes the most comprehensive model done for the Oil Sands Region.

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“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, the lead author of a paper on the subject.

PAHs end up released during the process of extracting petroleum from the oil sands. Environmental Impact Assessments have so far only considered the PAHs that release directly into the atmosphere. The risk associated with those direct releases fell within acceptable regulatory limits, officials said.

However, the model used by Parajulee and Wania takes into account other indirect pathways for the release of PAHs not assessed before or deemed negligible. For instance, they found evaporation from tailings ponds – lakes of polluted water also created through oil sands processing – may actually introduce more PAHs into the atmosphere than direct emissions.

“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,” Parajulee said.

The higher levels of PAHs the UTSC scientists’ model predicts when accounting for emissions from tailings ponds are consistent with what they have actually measured in samples taken from areas near and in the Athabasca Oil Sands Region.

The researchers also found tailings ponds emissions are likely not significant contributors of relatively involatile PAHs to the Oil Sands Region atmosphere. Instead, other emissions sources not taken into account by the environmental impact assessment, such as blowing dust, are probably more important for these chemicals.

The researchers modeled only three PAHs, which they believe are representative of others. Still, they say, their model indicates better monitoring data and emissions information can improve understanding of the environmental impact of the oil sands even further.

“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.”

Wednesday, March 21, 2012 @ 12:03 PM gHale

It has been almost two years since the April 20, 2010 explosion on the BP Deepwater Horizon drilling rig in the Gulf of Mexico and scientists are now getting a handle on the impact the disaster had on the environment.

For months, crude oil gushed into the water at a rate of 53,000 barrels per day before workers were able to cap the well July 15, 2010.

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Oil from the Macondo well made it into the ocean’s food chain through the tiniest of organisms, zooplankton, a new study said.

Tiny drifting animals in the ocean, zooplankton are useful to track oil-derived pollution. They serve as food for baby fish and shrimp and act as conduits for the movement of oil contamination and pollutants into the food chain. The study confirms that not only did oil affect the ecosystem in the Gulf during the blowout, but it was still entering the food web after they capped the well.

Oil, which is a complex mixture of hydrocarbons and other chemicals, contains polycyclic aromatic hydrocarbons (PAHs), which can act as a fingerprint and determine its origin. Researchers were able to identify the signature unique to the Deepwater Horizon well in the Gulf of Mexico, where 11 workers perished in the April explosion.

“Our research helped to determine a ‘fingerprint’ of the Deepwater Horizon spill—something that other researchers interested the spill may be able to use,” said Dr. Siddhartha Mitra of East Carolina University. “Furthermore, our work demonstrated that zooplankton in the Northern Gulf of Mexico accumulated toxic compounds derived from the Macondo well.”

The team’s research indicates the fingerprint of the Deepwater Horizon oil spill was in some zooplankton in the Gulf of Mexico ecosystem at low levels, as much as a month after capping the leaking wellhead. In addition, the extent of the contamination seemed to be patchy. Some zooplankton at certain locations far removed from the spill showed evidence of contamination, whereas zooplankton in other locations, sometimes near the spill, showed lower indications of exposure to the oil-derived pollutants.

“Traces of oil in the zooplankton prove that they had contact with the oil and the likelihood that oil compounds may be working their way up the food chain,” said Dr. Michael Roman of the University of Maryland Center for Environmental Science.

The study was led by East Carolina University with researchers from the University of Maryland Center for Environmental Science, Oregon State University, Georgia Institute of Technology, and U.S. Geological Survey.

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