Heavy oil and bitumen from oil sands needs to be “detoxed” before shipping, by train or pipeline
April 14, 2015
What is news:
- Faced with multiple examples of long-term harm and very expensive cleanup of heavy oil that sank in waterways and oceans, as well as pressures to transport dilbit, a Royal Society of Canada Expert Panel is examining environmental fate and impacts of crude oil released into aqueous environments.
What is known:
- Bitumen (the near-solid product of oil sands) is mixed with diluent (solvents) to make liquid “dilbit”.
Toxicity of bitumen, dilbit and other heavy crude products is more complex, severe and longer term than lighter petroleum liquids and natural gas.
As light oil reserves are depleted, increasing quantities of dilbit are being transported, by rail and pipelines, with increasing risks of spills.
Train derailments and pipeline leaks are very costly. Cleanup of the Enbridge pipeline leak of Canadian dilbit into the Kalamazoo River in Michigan topped $1.2 billion. The Lac Mégantic train crash killed 47 and cleanup is topping $400 million.”
Risks of complex mixtures are more than the sum of the parts
“… and remember to bring your medications and supplements to your appointment,” your doctor reminds you. The doctor needs to know all the medications and supplements that you are taking, and for good reason. They can interact, counter-act and even magnify the effect of potent agents.
If that isn’t complicated enough, some drugs have different effects at low doses compared with high doses.
Pharmacists also routinely dole out such advice. They know that biological effects often are not a simple sum of the effects of individual ingredients. The same is true for pharmacology’s cousin, toxicology. It covers similar territory, but with less research on specific environmental contaminants than drugs, interactions are more poorly understood.
Take, for example, petrochemicals. Decisions to ship crude oils across the country, by train or pipeline, should weigh options according to risks from spills of the material being shipped. Faced with complex mixtures and incomplete information, operators and regulators (Health Canada, Environment Canada, the National Energy Board and others) generally add up a few recognized components and ignore the rest. Pipeline applications propose shipping anything from light crude to diluted bitumen (“dilbit”). The elephant in the room is that these products pose widely different risks in the case of spills, and the risks and benefits of shipping are borne by different people.
Adding up toxicity works when chemicals are similar, but is misleading when they are very different. Classes of chemicals with interacting effects, that cannot be added together to estimate risk, include: toxic metals, polyaromatic hydrocarbons (PAHs), reduced sulphur compounds, chemicals that interfere with hormone actions (endocrine disruptors) and solvents. If you mix all of these together, you have a worst-case for broad-ranging toxicity. This also happens to be a recipe for dilbit.
Moving along the petrochemical continuum from natural gas, to light and heavy crudes, to bitumen, products generally become more complex and more toxic.
For example, risks along the Energy East pipeline, proposed to be converted from natural gas to dilbit would change from a transient (albeit very serious) risk of an explosion and fire, to risks of explosion of diluent plus long term lingering risks from persistent bitumen components.
Refining can shift a product to a less toxic category. Upgrading bitumen lowers its toxicity and persistence, as heavy metals and sulphur are removed, and PAHs are made into lighter, less toxic compounds. A bonus is that the material will flow on its own, removing the risks of diluent as well as the need to return it to Alberta.
Processing bitumen before long distant transport is a win all around. It would add value, create jobs, and reduce risks and associated costs for public health and the environment.
Why would we impose high, unnecessary toxic risks across the entire country? It is time to draw the line in the oil sands, to create jobs in Canada rather than shipping toxic bitumen across the continent, only to be exported and refined elsewhere.
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For further information contact:
Meg Sears, PhD
Co-chair and science advisor, Prevent Cancer Now
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