"Consider a picture such as Nickel Tailings #34from Burtynsky's "Mines and Tailings," a series devoted to the environmental aftermath of metal mining and smelting. Under a cool, grey sky, against a wintry violet backdrop of distant trees, a brilliant orange river swerves toward the camera from within a deep brown landscape. Fauvism has taught us to tolerate, even to relish, a pictorial anomaly such as a flaming orange river. From abstract painting, we have learned to admire the bold, simple surface design we find in Burtynsky's Nickel Tailings #34.But such enjoyments depend on our not thinking too hard about a bright orange river as a chemical and ecological reality: we know intuitively that in nature a river of this colour must spell trouble. We might suppress this thought momentarily by wondering whether Burtynsky has somehow re-tuned his picture's colour through some trick of digital or darkroom magic. But in the...