Thanks for your reply.

My question would be what is the source of the metals. Naturally occurring as a part of the bees gathering nectar and pollen. Or, contamination from water or the products used to build the hives?

Same as going through your mouth. But the risk of mineral oil vapors damaging smell receptors is pretty high. Exposed nerve ending directly in the path of those vapors seem like a bad thing happening in the long term.