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New research findings stemming from collaboration between scientists at Queen's University and Environment Canada shows that ~50 years of Athabasca oil sands development has left a legacy of contaminants in lake ecosystems.
Controversy has characterized discussions on whether contaminant levels in regional ecosystems can be attributed to expansion of oil sands mining and processing operations. Due to the lack of direct monitoring data predating industrial activities, researchers used the natural archives preserved in lake sediments to reconstruct past contaminant levels and ecological changes.
"Our approach tells a consistent story of increased contaminants and ecological change that has occurred in the region since industrial development of bitumen resources began," says lead author Joshua Kurek, a Postdoctoral Fellow at Queen's University, Department of Biology. "Today, our study lakes are very different compared to 50 years ago, and are on a path of unprecedented change."
The study revealed that toxic substances known as polycyclic aromatic hydrocarbons (PAHs) and dibenzothiophenes (DBTs), prominent components of Athabasca oil sands bitumen, have both increased in lake sediments since oil sands development began in the late-1960s. Additionally, increased contaminant levels were observed from one lake ecosystem ~90 km northwest of the major development area. This suggests that oil sands contaminants are deposited a greater distance than previously believed.
While the sediment measures showed PAH increases that paralleled oil sands development, the concentrations of contaminants were low compared to those typical of urban lakes.
To date, negative effects of PAHs on key invertebrates were not yet apparent. Instead the effects of climate change appear to have outweighed those of PAHs, and have resulted in higher abundances of zooplankton grazers because of enhanced algal production and greater food availability.
"Given that oil sands development will undoubtedly increase, we are certain that these trends will accelerate, and increased development will likely impact ecosystems farther from the current pollution sources," notes Queen's University professor John P. Smol, Canada Research Chair in Environmental Change. "Combined with the effects of climate change and other environmental stressors to aquatic ecosystems, these results are worrying."
This study, published in the prestigious Proceedings of the National Academy of Sciences of the United States of America, illustrates that multiple environmental stressors, including local industrial activities, have affected Athabasca oil sands lake ecosystems for nearly half a century.
Other members of the research team include Research and Physical Scientists from Environment Canada's Aquatic Contaminants Research Division: Dr. Jane Kirk, Dr. Derek Muir, Ms. Xiaowa Wang, and Dr. Marlene Evans.
Funding for the
research was provided by Environment Canada and NSERC.
PLEASE
NOTE: A PDF of the study can be obtained from the
Proceedings of the National Academy of Sciences
of the United States of America website, or contact Dr. John
P. Smol at
smolj@queensu.ca
Contact:
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Queen's University
Kingston, Ontario, Canada
613-533-2877
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NOTE: For high-resolution JPEGS related to this paper, Click Here.
| Joshua Kurek Paleoecological Environmental Assessment and Research Lab (PEARL) Department of Biology, Queen's University 116 Barrie St. Kingston, ON, Canada, K7L 3N6 Tel: 613-533-6000 x75143 Email: joshua.kurek@gmail.com |
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Jane L. Kirk |
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Derek C. G. Muir |
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Xiaowa Wang |
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Marlene S. Evans |
| John P. Smol Paleoecological Environmental Assessment and Research Lab (PEARL) Department of Biology, Queen's University 116 Barrie St. Kingston, ON, Canada, K7L 3N6 Telephone: 613-533-6147 Email: smolj@queensu.ca |
Links to some of the media coverage of this paper:
CBC's The Nature of Things Special-Tipping Point (at about 39 min)
