Is there some more detailed source explaining how this conclusion was reached? What's distinct about Chinese lead / how this kind of evaluations are done?
>the results indicate that the colossal statue is most likely an elaborate reassembly of what was initially a zhènmùshòu (镇墓兽 "keeper of tombs") fused in the Tang period (609-907 AD) with copper from the mines of the lower basin of the Yang-tze River, the Blue River in southern China. This is confirmed by accurate analyses of lead isotopes, which leave in the bronze unmistakable traces of the original mines from which the copper was extracted.
The implication is that the mines themselves have different isotope signatures that have been established in previous archaeological studies.
So they are looking for the signature lead impurities in that copper. They use isotope analysis to find the lead impurities in the copper.
The first mentions lead once. The second does not mention any region of present-day China, as far as I can tell. I can't see the information there.
The first link explains how we use isotopes in this fashion. The second explains that lead has some useful ones.
There's some more info on the lion's measurements here, but I haven't been able to find the study that was presented in September
https://journals.iucr.org/j/issues/2024/03/00/in5093/in5093....