from High Performance Biomaterials
by Scyzcher, p212
"Titanium does leak from the implant, as evidenced by the occasional blackness of the tissue surrounding the implant. No adverse tissue effects have been demonstrated ... no evidence was found of any biochemical or hematologic toxicity ... Persistent dietary intake of the metal results in some accumulation in the heart, lungs, spleen and kidneys although no adverse effects have been observed ... "
For Tattoo charges of "toxic" tattoo ink containing toxic particles we can argue the same.
For Piercing we can argue the same to support the continued use of 316L.