Nah, I think it would be more surprising if you couldn't track this stuff down. In the industrial and construction world, everything works off of POs and work orders. When a company buys or sells anything, there's almost always a paper trail, and usually some internal records showing what material went where. If you have the money to spend on the investigation (and an easy-to-detect signature in the material itself, like radioactivity) you can probably trace contamination all the way back to the hole in the ground it came out of.