U.S officials are struggling to figure out how bitumen from the Alberta oilsands will behave if there is a spill either from a pipeline or into the Salish Sea, the fragile ocean environment between Canada and the U.S.
As the U.S. debates the future of the TransCanada Keystone XL pipeline, which would transport Alberta oil to the Gulf Coast, and Canada looks at Kinder Morgan's proposed twinning of the Trans Mountain pipeline and the proposed Enbridge Northern Gateway project, there is a growing urgency to find out how diluted bitumen behaves if there is a spill, said scientists, policy makers and environmentalists gathered in Seattle for the Salish Sea Ecosystem Conference this week.
“Does it float or not float? That's the question,” said Gary Shigenaka, marine biologist with the U.S. National Oceanic and Atmospheric Administration (NOAA) hazardous materials response division, flashing a picture of thick, black bitumen extracted from the oilsands.
NOAA is studying the behaviour of bitumen and the diluent with which it is mixed to make the peanut-butter like substance flow through pipelines, but, so far, there are few concrete answers, Shigenaka said.
Studies show that although diluted bitumen — dilbit — initially floats in water, it sinks when it is mixed with sediment, which would happen in high turbulence or in areas such as a river estuary, Shigenaka said.
Fears about the behaviour of bitumen in water have been growing since the 2010 spill of about 3.2 million litres (843,000 gallons) of thick crude into a tributary of the Kalamazoo River in Michigan. It was the first spill of diluted bitumen from Alberta into a waterway, and agencies struggled to cope with a substance that released toxic fumes from the diluent and then sank as the bitumen mixed with river sediment.