“…The most extensively studied element in environmental samples is Pb. Crustal Pb and ore Pb show a pronounced difference in their isotopic composition, owing to the fact that the production of 206 Pb, 207 Pb and 208 Pb as a result of the decay of 238 U, 235 U and 232 Th, respectively, has been going on for a much longer time in the crust. Thus, it is quite easy to distinguish between natural, geogenic Pb (crustal signature) and anthropogenic Pb (ore signature) and calculate the relative contribution of the sources, even with single-collector instrumentation.…”