Click each heading for more detailed information.
Tailings are a waste byproduct from the oilsands extraction processes used in mining operations.
- Tailings consist of a mix of water, sand, silt, clay, contaminants and unrecovered hydrocarbons.1
Tailings are toxic.
- Tailings contaminants include naphthenic acids, polycyclic aromatic hydrocarbons, phenolic compounds, ammonia, mercury and other trace metals.2
- The liquid found in oilsands tailings ponds is acutely toxic to aquatic organisms3,4and mammals.5,6
- Naphthenic acids are considered to be one of the most significant environmental contaminants resulting from the development of the oilsands,7,8 the effects of which are still largely unknown.9,10
- The National Pollutant Release Inventory publicly reports the amount of toxic materials disposed in tailings ponds each year. While more than 75 toxic are tracked, some specific aggregate amounts for 2010 include:11
- Arsenic: 300,905 kg
- Benzene: 178,200 kg
- Lead: 756,793 kg
- Mercury: 824 kg
- Toluene: 1,169,000 kg
- Sum of all PAH compounds: 341,997 kg
- Between 2006 and 2010, total amount of mercury added to all tailings ponds per year increased by 80%, lead by 50%, and arsenic by 21%.12
Tailings are stored indefinitely in open lakes that cover an area approximately 50% larger than the city of Vancouver.13
- Tailings lakes occupied 176 square kilometres in 2010.14
- Tailings are expected to expand nearly 50% in area by 2020 to 250 square kilometres.15
More than 200 million litres of mature fine tailings are produced each day,16 enough to fill Toronto’s Rogers Centre (formerly the Sky Dome) 47 times in a year.17
- Over 830 million cubic metres of mature fine tailings18 — more than double the volume of water in Alberta's Sylvan Lake — currently require long-term containment.19 The volume of liquid tailings will grow more than 40% from 830 million cubic metres to more than 1.2 billion cubic metres in 2030.20
- The volume of tailings on the land will continue to grow until 2060 where the volume stabilizes at 1.3 billion cubic metres.21
Tailings lakes seep. The exact amount of seepage is either not known or has not been made public.22
- Modelled estimates suggest that 11 to 12.6 million litres of tailings leak from tailings ponds each day.23,24
updated April 2013
- 1. M. D. MacKinnon et al., "Water Quality Issues Associated with Composite Tailings (CT) Technology for Managing Oil Sands Tailings," International Journal of Surface Mining, Reclamation and Environment 15, no. 4 (2001).
- 2. P. G. Nix and R. W. Martin, "Detoxification and Reclamation of Suncor's Oil Sand Tailings Ponds," Environmental Toxicology and Water Quality 7, no. 2 (1992).
- 3. M. D. MacKinnon and H. Boerger, "Description of two treatment methods for detoxifying oil sands tailings pond water," Water Pollution Research Journal of Canada 21 (1986): 496-512.
- 4. Alan Scarlett, Charles West, David Jones, Tamara Galloway, and Steve Rowland, “Predicted Toxicity of Naphthenic Acids Present in Oil Sands Process-Affected Waters to a Range of Environmental and Human Endpoints,”Science of The Total Environment 425 (2012).
- 5. U.S. Environmental Protection Agency, Office of Toxic Substances, "Fate and Effects of Sediment-bound Chemicals in Aquatic Systems," Proceedings of the Sixth Pellston Workshop, Florissant, CO, August 12-17, 1984.
- 6. Royal Society of Canada Expert Panel, Environmental and Health Impacts of Canada’s Oil Sands Industry (2010), 129.
- 7. V. V. Rogers et al., "Acute and Subchronic Mammalian Toxicity of Naphthenic Acids from Oil Sands Tailings," Toxicological Sciences 66 (2002).
- 8. John V. Headley, Kerry M. Peru, and Mark P. Barrow, “Mass Spectrometric characterization of naphthenic acids in environmental samples: a review,” Mass Spectrometry Reviews 28 (2009).
- 9. Royal Society of Canada, Environmental and Health Impacts of Canada's Oil Sands Industry (2010).
- 10. Scott, A. C., W. Zubot, M. D. MacKinnon, D. W. Smith, and P. M. Fedorak, "Ozonation of oil sands process water removes naphthenic acids and toxicity" in Chemosphere 71: 156-160.
- 11. Compiled from the National Pollutant Release Online Inventory. Volumes include reported data from CNRL Horizon, Syncrude Mildred, Syncrude Aurora, Shell Muskeg River and Suncor Mine.
- 12. Compiled from the National Pollutant Release Online Inventory. Volumes include reported data from CNRL Horizon, Syncrude Mildred, Syncrude Aurora, Shell Muskeg River and Suncor Mine.
- 13. The City of Vancouver is 114.7 square kilometres in area (NationMaster - Encyclopedia - Vancouver, British Columbia ).
- 14. Alberta Environment & Water, "Oil Sands Information Portal: Tailings Ponds – Tailings Ponds Surface Area."
- 15. The Pembina Institute and Water Matter, Tailings Plan Review.
- 16. Calculated based on the production of 1.5 barrels of mature fine tailings per barrel of bitumen produced through mining (R. J. Mikula, V. A. Munoz and O. Omotoso, Water Use in Bitumen Production: Tailings Management in Surface Mined Oil Sands, presented at the World Heavy Oil Congress (Edmonton, AB: 2008).) and the production of 893,000 barrels of bitumen per day by mining in 2011 (Energy Resources Conservation Board, ST98-2012: Alberta’s Energy Reserves 2011 and Supply/Demand Outlook—Overview (2012)).
- 17. The Rogers Centre has a volume of 1.6 billion litres. Rogers Centre, “Fun Facts and Figures” (accessed January 21, 2013).
- 18. Alberta Environment & Water, Oil Sands Information Portal: Tailings Ponds – Total Tailings Pond Volume
- 19. Sylvan Lake has a volume of 412 million cubic metres (Patricia Mitchell, Assessment of Water Quality in Sylvan Lake (Alberta Environment, Water Sciences Branch, 1999), 5).
- 20. R.H. Houlihan and C. E. Hale, "Alberta mine reclamation and abandonment requirements," in Mine Closure 2011, Proceedings of the Sixth International Conference on Mine Closure, 18-21 September 2011, Alberta, Canada, vol. 2, 13. (Based on data from 2009 ERCB Directive 74 submissions.)
- 21. R.H. Houlihan and C. E. Hale, "Alberta mine reclamation and abandonment requirements," in Mine Closure 2011, Proceedings of the Sixth International Conference on Mine Closure, 18-21 September 2011, Alberta, Canada, vol. 2, 13. (Based on data from 2009 ERCB Directive 74 submissions.)
- 22. Royal Society of Canada, Environmental and Health Impacts of Canada's Oil Sands Industry.
- 23. M. Price, 11 Million Litres a Day: The Tar Sands' Leaking Legacy (Environmental Defence, 2008).
Royal Society of Canada, Environmental and Health Impacts of Canada's Oil Sands Industry.