Generally Gold (aurium) is not bioreactive, it's hardly reactive at all hence it's lustre in the wild since it doesn't tarnish or bond easily. Goldschlager has gold flake in it for human consumption. It's generally considered safe to consume for this reason. The quantity to make an LD50 of inhaled gold would be considerable I imagine, but have no data.
This made me wonder what the health benefits of having lungs of gold might be.
Remains to be seen, perhaps?