Above-ground atomic explosions and reactor leaks during the past century have produced a pretty funny atmosphere full of exotic heavy isotopes. In radiocarbon calibration this error source is called "bomb radiocarbon". A few years ago it was suggested that a person's age might be determined through looking at the amount of various isotopes in some bodily tissue (was it the eye's lens?) and cross-referencing it with the historic data on spikes and troughs in the abundance of various isotopes.
Now the always readworthy Chris Catling tells the readers of Current Archaeology #265 (April) of another way that our sloppy ways with fissile material impact our lives - our cultural heritage, specifically!
"Metal theft doesn't just take place on dry land; law abiding divers have been reporting an increase in theft from the wrecks of HMS Aboukir, Hogue and Cressy, sunk by a U-boat in the North Sea on 22 September 1914 with the loss of 1,459 lives. ... apparently the steel structure of the ships ... [T]he amount of radioactive isotopes in the atmosphere has increased, and these get into steel, making it weakly radioactive when air is blown into the furnace ...Read the comments on this post...Some forms of scientific and medical equipment (such as Geiger counters and radiation-detecting body scanners) need what is known as "low-background steel", the chief source of which is naval vessels constructed prior to 1945 and protected from contamination by the North Sea ...
(pp. 46-47)