the titanium I use is medical implant grade so I hope you wouldn't have a problem with it.. Hahah. No Copper is implant grade, but what I use is food grade, same thing used in copper pots and pans, so it's safe for contact and long term exposure. Most brass has lead in it, the brass I use is LEAD FREE naval brass and I confirm this with the material data sheet after testing, so it's safe... But I hear you, with so many things out there with unknown materials in them if be worried too.
Then again if you are using a chrome plated atty or cartomizer there are much more questionable things in there.. I've pulled apart cartomizers (in the past) and found melted plastic on wires, burned poly filler, and super glue holding things in place. These days I'm overly safe if anything and I wouldn't sell anything that had questionable materials in it. In other words, I wouldn't sell something I wouldn't use myself, and I'm quite "tin foil hat" about it

haha