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Environmental Forensics and the Alberta Oil Sands

By: , Posted on: October 9, 2013

Alberta Oil Sands
Open pit mine for oil sands in Alberta.

The oil sands of Alberta are receiving a lot of interest internationally for the potential environmental impacts due to mining and SAGD (steam-assisted gravity drainage) extraction of this resource as well as for the debate around the Keystone XL pipeline.  Even Robert Redford is latest to give his view. He may have a few facts wrong but that never stopped anyone in Hollywood from voicing their opinions.  This blog is not meant to address this debate, as it would likely require a very long essay to speak to both sides of the argument adequately.

One marker chemical class for oil sands monitoring is a group of persistent organic pollutants (POPs) known as polycyclic aromatic hydrocarbons (PAHs).  PAHs are naturally present in the crude oil itself (known as petrogenic PAHs) as well as formed during any combustion process (pyrogenic PAHs).  To make things a bit confusing, many of the PAHs can be formed in both pyrogenic and petrogenic sources.  The use of indicative PAHs can be used to distinguish between these potential sources.

Whether you agree or disagree with oil sands development, one fact that is true: the impact of oil sands mining, as measured by PAHs in the environment, has been conclusively demonstrated only very recently.  Two publications in 2013 showed this. There were published by Kurek et al and Jautzy et al.  Both of these papers exemplify the principal of environmental forensics: to elucidate the source and timing of a contaminant release.

The papers used sediment cores from lakes around the oil sands development in Alberta.  Sediment cores provide a chronological record of deposition of PAHs.  Sediment cores were extracted from the lakes and layers of the sediments were age dated using 210Pb, 137Cs, and 226Ra radioisotopic techniques.  Using this technique, combined with the measurement of PAHs using very sensitive methods using isotope dilution mass spectrometry, Kurek et al showed that levels of PAHs increased dramatically in the early 1970s in the region.  The rise in concentrations was attributed to the mining of the oil sands as the timing coincides to when mining began.

In addition, Kurek used indicative PAHs such as the alkylated substituted PAHs and dibenzothiophenes to demonstrate that the increased amounts of PAHs are related to petrogenic sources.  The study by Jautzy et al took the research one step further.  Following similar methodologies, they were able to confirm the Kurek study as well as confirm the likely source of the PAHs being released in the oil sands region.  Using stable isotopes of selected PAHs, Jautzy et al confirmed that the PAHs were increasing in the region likely as a result of the open pit mining activities and from deposition in the lakes of surface erosion of PAH laden soils from these activities.  This is important as there are two different extraction techniques used for oil sands extraction – open pit mining (the one most commonly shown on TV and in the press) and SAGD extraction.

Environmental Forensics for Persisten Organic PollutantsBoth of these studies are great examples on the use of environmental forensics techniques for determining the source and timing of a release.  Oil sands developers can now use this information to track PAH contaminants in the surrounding environment, which is something they were not able to do since baseline data was either very limited or was not collected at the time when development began in the region.

It should be noted that the levels of PAHs measured in the lake sediments, even though they are shown to be increasing, are still well below applicable environmental guidelines.   These environmental forensics studies were simply able to show that the increase, even though concentrations are low, is still measurable.

The environmental debate of the oil sands will continue and the use of environmental forensics will likely continue to be used to address these issues.

My upcoming book entitled Environmental Forensics of Persistent Organic Pollutants delves deeper in these topics and is now available for pre-order at a $25 discount. Chapter 6 of the book, Atmospheric Fate and Behavior of POPs discusses the topic of atmospheric distribution of contaminants as well as their fate and transport, including the subject matter of PAHs.

About the Author:

Dr. Court SandauDr. Court Sandau (@EnviroCertainty) is the principal of Chemistry Matters, a niche environmental forensics and chemistry consulting company and is an adjunct professor at the University of Calgary in the Schulich School of Engineering. Dr. Sandau’s experience includes working at the Centers for Disease Control and Prevention (CDC) where he managed a laboratory responsible for the analytical toxicology and exposure assessment of humans to environmental contaminants.

Dr. Sandau also worked at the National Wildlife Research Center measuring contaminants in environmental, wildlife and fish samples with the purpose of examining the biomagnification, biotransformation, and toxicological effects of priority pollutants in the arctic and Great Lakes food webs. Dr. Sandau’s technical expertise includes analytical and environmental forensic chemistry, toxicology and risk assessment. Dr. Sandau has written over 100 publications and given numerous presentations internationally to his peers. Dr. Sandau’s knowledge and expertise are often retained to provide litigation support and expert witness testimony. You can read more about Dr. Sandau and his work at the Chemistry Matters blog.

 

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