There are analysts in Canada, according to this website posting from north of the border, that have looked at their nation's natural resource use for various exports to the US and don't like what they see.

Note the linkage to the production and export of Canadian tar sand crude oil - - a process that uses substantial amounts of water, which like oil is also a finite resource.

And the tar sands provide the crude oil that will supply the expanded refining capacity on the US Great Lakes at Whiting, Indiana (British Petroleum) and Superior, Wisconsin (Murphy Oil).

It takes three gallons of water to produce a barrel of crude oil for export, with polluted wastewater to deal with in Canada, experts say.

Then it takes more water to refine that crude oil, and produces more waste that has to be dealt with by the refinery - - on the Great Lakes.

Murphy Oil Co. is looking for a financial partner to help expand the capacity of its refinery on Lake Superior in northern Wisconsin from 35,000 barrels a day to 235,000.

I examine some of the issues in an op-ed published in the Madison Capital Times.