In specimens from one of the donors, levels of cadmium and mercury were increased in the lymph nodes but not in the skin samples. These elements may have migrated from tattoos that were not used in this study, the authors note, or through other routes of exposure.
TiO2, which was also found in skin and lymph node samples, is a white pigment commonly used to create varying shades of color in tattoos. It is also used in food additives, sunscreens, and paints. It has been associated with delayed healing and itching when used in tattoos, and the European Chemicals Agency recently declared that it is carcinogenic when inhaled.
“The size and degree of shading of the tattoo will determine the amount of ink injected into the body,” said Dr Castillo-Michel. “Therefore, the amount of toxic substances will depend on the size of the tattoo and if a contaminated ink has been used.”
The authors plan to continue investigating the burden of pigments and heavy metals on other, more distant internal organs and tissues, so that other potential sites of migration of the ingredients of tattoo ink can be identified.
“Biodistribution, metabolism, and a potential excretion of substances are key points necessary to assess the toxicity of compounds in tattoo inks,” said Schreiver. “Especially when organic pigments are transported to the liver, a higher rate of metabolism can be expected. The toxicological properties of the reaction products are completely unknown so far.”
The study was supported by the intramural research project at the German Federal Institute for Risk Assessment. The authors have disclosed no relevant financial relationships.