Canada's oil sands industry is in the throes of a major expansion, powered by C$20 billion ($19 billion) a year in investments. Companies including Syncrude Canada, Royal Dutch Shell, and ExxonMobil affiliate Imperial Oil are running out of room to store the contaminated water that is a byproduct of the process used to turn bitumen -- a highly viscous form of petroleum -- into diesel and other fuels. To tackle the problem, energy companies have drawn up plans that would transform northern Alberta into the largest man-made lake district on earth. One big concern surrounding end-pit lakes is that the contaminated water will spread through the boreal ecosystem, the tract of trees and marshland that stretches around the top of the world from Canada to Russia and Scandinavia.