highly unlikely I’d have thought that your garden bonfire temperature will ‘burn’ copper as copper is pretty damn stable.
At most, and the fire will need to be hot to do it, you’ll have melted it and once it’s cooled will have an interesting garden ornament in the ash. It won’t be dissolving appreciably into the watercourse or anything where it can have any real harm, would be my opinion.
Copper (salts) colour a flame bluey-green typically (copper (I) is blue, but that’s not the usual oxidation state of copper); several others do have blue flames but of these the more suspect would be I think lead.
In respect of jonnyboi – it’s boron that does that. Copper summons up dancing nymphs with mead and insatiable appetites for lust. Where did you say you lived again?