Unrevealing the real pigment composition of green tattoo inks

Since losing their maverick image, tattoos are no longer fringe groups markings, but a widespread practice with estimated 120 million people tattooed worldwide in 20161. This poses problems of safety of the materials injected under the skin. In spite of a foreseeable concern, no uniform regulation has been put in place to monitor the inks composition, determine the potential risks for human health and consequently restrict, whether necessary, the use of specific inks. There are indications on this issue by the ResAP(2008)12, dealing with cosmetics, and safety of the tattooing procedure, which were accepted in few countries in Europe, and largely neglected by the others. Meantime, new indications are being proposed by the Committee for Risk Assessment (RAC- Nov.2018)3 and the Committee for Socio-Economic Analysis (SEAC- also Nov.2018)3. In this overall scenario, aiming at tackling tattoo inks safety, the first issue to address is their actual composition. Inks can be considered as roughly being composed of a pigment, imparting the colour, and a vehicle, ensuring the ink fluidity and asepticity. We selected green inks and performed multiple-techniques investigations to determine the actual pigment composition. In all of them, PG36, a hexabrominedecachlorine Cu-phthalocyanine was indicated as pigment both on the bottle labels and on the safety sheets, and PG7, a hexadecachlorine Cu-phthalocyanine was found, instead, which is restricted in countries where legislation on tattoo inks is enforced4. More false declarations on ink compositions were found, also for additional pigments in the inks, even if none of them is restricted4. Whitening agents such as TiO2 nanoparticles may be present, but in this case, additional dispersing agent, with non-negligible Al and Si content were not declared. Issues on TiO2 nanoparticles size are also to be considered for their potential cytotoxic aspect4. ___________ [1] S. Everts, Chemical and Engineering News, American Chemical Society, [2] Council of Europe Resolution ResAp(2008)1 on requirements and criteria for the safety of tattoos and permanent make-up Feb. 20th 2008. [3] Compiled RAC and SEAC Opinion on an Annex XV dossier proposing restrictions on substances used in tattoo inks and permanent make-up ECHA/RAC/RES-O-0000001412-86-240/F, ECHA/SEAC/ ECHA/SEAC/RES-O0000001412-86-265/F, https://echa.europa.eu/it/registry-of-restriction-intentions/-/dislist/details/0b0236e180dff62a [4] E.M. Bauer, T. De Caro, P. Tagliatesta, M. Carbone, Dyes and Pigments 2019, 167, 225-235.