All of the oil cannot be recovered from the Sask., river: expert

It's been two weeks since the Husky oil spill, and ecologist Steve Hamilton predicts it will be weeks more before the extent of the spill is known.

The ecologist from Michigan State University studied the Kalamazoo watershed for years prior to the 2010 pipeline spill that affected the Kalamazoo River.

He spoke with CBC Saskatchewan's Morning Edition on Wednesday.

Oil on the bottom

An expert with Husky said there has been no evidence ofoil on the bottom of theriver.

"I would venture to guess that it's too preliminary to make that declaration," Hamilton said. "You need more time to see that."

When oil spills,the chemicals used to dilute the heavy oil evaporate asit floatson the surface.That means the remaining substance in the river is more similar to the heavy oil itwas prior to being diluted, he said.

Hamilton added thecrude-like residue that remains sticks to particles in the bottom of the river, and this happens on amicroscopic level.

"It's not like big tar patties or layers of oil would be found on the bottom."

The particles of oil attached to sedimentwill move downstream until they reach a place where they can settle. However, it won't move quickly.

"It might take weeks, even months, for it all to get there."

Comparisons to the Kalamazoo

"Every oil, and every environment it spills into, has unique characteristics, but infactthese two rivers share a lot in common," he said.

Hamilton said it wasdifficult to get the tiny oil particles out of the Kalamazoo Riverbecause they were so hard to find. He said there would be a similar problem in the Saskatchewan spill.

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In the Kalamazoo River, the remaining oil produced a sheen whenever it was disturbed by a fish or boats.

The lingering sheen helped them locate some of theoil, but there were still other issues.

"We were really frustrated by the lack of information on what is exactly in the pipelines," he said."To this day we don't know precisely the composition of the material used to dilute it."

The cost of a spill

The cleanup of the Kalamazoo River took a lot of time, money and people, he said.

"It took $1.2billion andfour years."

There were thousands of people involved in the cleanup. Six years later, theeffort appears to have paid off.

You reach a point where you can't get every bit of oil out without destroying the ecosystem you're trying to save.-Steve Hamilton, ecologist

"I'm happy to say there's virtually no trace of spilled oil," he said. "The fish and wildlife and insect life on the bottom has returned to normal as far as we can tell."

Hamilton said environmental agencies need to be better prepared to handle the spills. He also said that they need to be studied when they happen

However,he cautioned the results of studies don't necessarily equate to asolution.

"Every new situation presents unique circumstances."

Hamilton says regardless of the cleanup effort, officials will never recover all of the spilled oil.

"In any event like this, you reach a point where you can't get every bit of oil out without destroying the ecosystem you're trying to save."