There is a way to determine the source of lead using lead isotopes. Here is a paper which shows that the high lead levels in a young bald eagle were associated with lead paint, lead in gasoline and lead smelting and not with lead ammunition.

"The Use of Lead Isotope Analysis to Identify Potential Sources of Lead Toxicosis in a Juvenile Bald Eagle (Haliaeetus leucocephalus) With Ventricular Foreign Bodies"

https://www.jstor.org/stable/44806036

It would be nice if all research used those methods when lead was found to be contributing to the death or ill health of birds and other animals.


Regards - Ian Forrester