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article imageStudy: Impact of diluted bitumen on young sockeye salmon deadly

By Karen Graham     Sep 12, 2018 in Science
Vancouver - A spill of diluted bitumen would put the survival of young salmon at risk even if the fish end up in clean water following exposure to the oil product, says new research from the University of Guelph.
New research led by Sarah Alderman, a post-doctorate researcher at the University of Guelph's department of integrative biology has found that even short exposure to diluted bitumen (dilbit) can be deadly to young salmon.
The new study added credence to a study published by Alderman last year that concluded tiny amounts of diluted bitumen weakens the chances of migrating salmon to make it back to the rivers and streams of their birth to spawn.
The new study, published in the September Journal of Aquatic Toxicology, studied the effects of diluted bitumen on early life stages of sockeye salmon (Oncorhynchus nerka).
A male and female sockeye salmon spawning in the Adams River of British Columbia Canada in October  ...
A male and female sockeye salmon spawning in the Adams River of British Columbia Canada in October, 2014.
William Rosmus (CC BY-SA 4.0)
Diluted bitumen - or dilbit
Bitumen has the texture of crumbling asphalt, and this means it needs to be diluted, or mixed, with another petroleum product so that it can flow freely through a pipeline. Bitumen's consistency also makes it more difficult to control than an oil spill because bitumen sinks, while oil can be corralled with booms and skimmed from the surface.
The necessity of knowing the impact of bitumen on native fish and salmon - along with the knowledge the Trans Mountain Pipeline expansion was going through the Fraser River watershed, Canada's largest freshwater salmon-bearing area, has put the potential for a spill on the minds of researchers.
In December 2017, Alderman told CBC Canada that B.C.'s commercial salmon and sport fishing industries are worth hundreds of millions of dollars and the species has significant cultural and spiritual importance to Indigenous people.
Trans Mountain
The study and its conclusions
In the study, 1,000 sockeye salmon eggs in each of four groups were exposed to four different dilutions of water-soluble dilbit from fertilization to the swim-up stage. Then the four groups were reared in clean water for 8 months.
We saw a lot of changes during the exposure," said Alderman. "We found a whole suite of effects from delayed hatching to increased mortality, increased developmental deformities and changes in growth and energy stores in the fish."
Alderman also noted that at least 50 percent of the fish exposed to the highest dilution of dilbit died within two months of being moved to clean water where they were to live and be observed for eight months.
"We found for about the first two months after moving them to clean water we had really high mortality even though they are not being exposed to the dilbit (diluted bitumen) anymore," said Alderman. "We saw mortality as high as 50 percent during that two-month period. Every day there's more dead and more dead."
A blast on the Deepwater Horizon drilling rig killed 11 men and unleashed 134 million gallons of cru...
A blast on the Deepwater Horizon drilling rig killed 11 men and unleashed 134 million gallons of crude oil into the Gulf of Mexico
, US Coast Guard/AFP
The different dilutions used were four micrograms of diluted bitumen per liter of water to 35 micrograms per liter to 100 micrograms per liter, Alderman said. The fourth group of eggs, a control group, was not exposed to the product. Alderman said the largest exposure amount of 100 micrograms per liter reflected the level of oil products measured along the shoreline of the Gulf of Mexico following the Deep Water Horizon spill in 2010.
Impacts on the Trans Mountain Pipeline decision
The recent Federal Court of Appeal decision overturning the approval of the pipeline expansion said the National Energy Board "unjustifiably excluded the consideration of marine shipping of bitumen in its approval process."
And basically, the Appeal Court said in so many words that environmental impacts from bitumen really weren't taken all that much into consideration, other than Kinder Morgan saying they would be careful.
Kinder Morgan Canada
"There's a lot of dilbit being transported in pipelines and most of it is transported very safely," Alderman said. "But as this industry expands the potential for spills increases. We're working to understand what to expect if it does happen."
In a statement, the Canadian Association of Petroleum Producers did not comment on the Guelph research, but said it is part of a separate and ongoing independent study to "provide a better understanding of the behavior of oil in the unlikely event of a spill on water."
And, an additional note - In 2016, Alderman was the lead authorin a study that looked at the effects of diluted bitumen exposure on juvenile sockeye salmon from cells to performance. The results demonstrated cardiac sensitivity to dilbit exposure that could directly impact sockeye migratory success.
The bottom line - With all these studies on the negative effects of bitumen on a salmon industry in British Columbia valued to be over $300 million annually, why in the world was this fact ignored in making the decision to OK the pipeline. And yes, petroleum is also important to Alberta's economy. But losing a resource like salmon will have far-reaching effects.
More about Bitumen, Crude oil, fish development, toxicity, Morphogenesis
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