Applicability of In Silico New Approach Methods for the Risk Assessment
of Tattoo Ink Ingredients
Abstract
Tattoo inks contain several substances, including organic and inorganic
pigments, additives, and solvents, which may pose a health risk to not
only the tattooed skin but also to other parts of the human body due to
intradermal exposure. Substances in tattoo inks are regulated by entry
75 in Annex XVII of REACH Regulation (EC) No. 1907/2006. However,
despite these legal requirements, a well-defined criterion for the
safety assessment of tattoo inks remains lacking. In this context, 2021
BfR opinion titled “Tattoo inks: minimum requirements and test
methods” proposed a comprehensive risk assessment of pigments using
in-vitro/in-chemico data in accordance with the OECD Guidelines and CLP
Regulation. However, in the absence of experimental data, new approach
methodologies (NAMs) can be used for data-gap filling. This work
evaluates the applicability of in silico NAMs for data-gap filling to a
list of tattoo ink ingredients identified by the JRC and BfR for
genotoxicity assessment. The experimental in vitro genotoxicity data was
acquired from the International Uniform ChemicaL Information Database
(IUCLID) which makes the non-confidential REACH Study Results publicly
accessible. The specific aims of this analysis were evaluation of in
silico genotoxicity predictions from publicly available QSAR tools and
structural alerts, development and validation of new QSAR models
specific to tattoo ink ingredients, and application of in silico models
for categorization and prioritization of data-poor ingredients for
further screening. Based on the workflow developed in this study, 4 high
priority, 11 medium priority and 2 low priority substances were
identified for further assessment.