Grave Peril, the third Dresden Files book, opens with Harry and Michael working together to exorcise a malicious ghost. Harry carries with him some "ghost dust", containing depleted uranium as a principal ingredient.
Suspension of disbelief is definitely necessary in a fantasy story, and I can accept the fantastic elements when they remain relatively consistent, but this one trips me up because it belongs to the real world.
"Depleted" just means that the uranium has had most of the fissionable U-235 processed out of it. It's still radioactive, and it's still highly toxic (in the biochemical sense, completely aside from the radioactivity.) Not the sort of thing that governments want falling into civilian hands, I'd imagine! And given that Harry is consistently portrayed, particularly in the early books, as being perpetually broke or near-broke, where in the world did he obtain a bunch of powdered depleted uranium? Has this ever been explained?