LC–MS/MS and ICP-MS Characterization of Toxic Elements and Organic Contaminants in Tattoo Inks

Tattoo inks deliver pigments and additives directly into the skin, which establishes a long-lasting route of exposure to potentially carcinogenic and toxic chemicals. Although evidence of health risks related to tattoo inks has grown, Australia remains unregulated in this area (unlike the European Union [EU], where strict chemical limits on tattoo inks have been enforced since 2022). In response, a research team made up of scientists from Australian colleges and universities analyzed 15 black and colored inks available on the continent using inductively coupled plasma mass spectrometry (ICP-MS), with untargeted liquid chromatography tandem mass spectrometry (LC–MS/MS) performed to determine if any additional restricted or toxic compounds were present in these inks. A paper based on their research was published in Journal of Hazardous Materials (1).

Tattoo inks are complex mixtures of pigments, solvents, and additives injected intradermally, creating a long-term exposure pathway that bypasses many of the body’s natural protective barriers (2,3). Toxicological concerns arise from both local and systemic effects, such as associations with cytotoxicity, genotoxicity, and oxidative stress (4,5). Among the toxic substances commonly detected in tattoo ink are arsenic, cadmium, and lead, which are classified as carcinogens and may have no safe threshold for chronic exposure (6–8).

The researchers state in their paper (1) that the only available Australian data concerning tattoo ink comes from a 2016 government report (updated in 2018), which reported that only 8% of tested inks would comply with Council of Europe Resolution ResAP(2008)1 standards (9). However, this report provides limited methodological detail. For example, key parameters for metal analysis, such as acid concentration, digestion conditions, dilution or filtration steps, limits of detection, and instrument type (ICP-MS or inductively coupled plasma optical emission spectrometry [ICP-OES]), were not specified. Furthermore, the survey which generated this data was conducted only once, predates the introduction of EU2020/2081, and, as the data cannot be quantitatively compared with similar studies conducted by Europe or the United States, the chemical composition of inks currently sold in Australia remains largely unknown. These limitations inspired the researcher’s study (1).

Eight of thirteen regulated elemental substances (antimony, arsenic, cadmium, chromium, copper, lead, selenium, and tin) discovered in the study exceeded European Union thresholds in at least one sample. Several pigment metals (titanium, aluminum, zirconium) were also detected at extraordinarily high levels, although not currently regulated. Untargeted LC–MS/MS identified compounds listed in EU2020/2081, including toluidine and sulphanilic acid, as well as other suspected toxicants. “These findings,” write the authors (1), “show that none of the tested inks would be legally marketable in Europe, highlighting a clear safety concern and regulatory gap in Australia.”

The authors conclude that harmonizing with EU regulations and instituting independent compliance testing “are urgent steps to reduce unnecessary toxic exposures” (1).

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References

1. Violi, J. P.; Westerhausen, M. T.; Tasevski, B. et al. Toxic Metals and Carcinogens in Tattoo Inks Available in Australia. J. Hazard. Mater. 2025, 140874. DOI: 10.1016/j.jhazmat.2025.140874
2. Kluger, N.; Koljonen, V. Tattoos, Inks, and Cancer. Lancet Oncol. 2012, 13 (4), e161–8. DOI: 10.1016/S1470-2045(11)70340-0
3. Battistini, B.; Petrucci, F.; De Angelis, I. et al. Quantitative Analysis of Metals and Metal-Based Nano- and Submicron-Particles in Tattoo Inks. Chemosphere 2020, 245, 125667. DOI: 10.1016/j.chemosphere.2019.125667
4. Neale, P. A.; Stalter, D.; Tang, J. Y. M. et al. Bioanalytical Evidence that Chemicals in Tattoo Ink Can Induce Adaptive Stress Responses. J. Hazard. Mater. 2015, 296, 192–200. DOI: 10.1016/j.jhazmat.2015.04.051
5. Arl, M.; Nogueira, D. J.; Schveitzer Köerich, J. et al. Tattoo Inks: Characterization and in vivo and in vitro Toxicological Evaluation. J. Hazard. Mater. 2019, 364, 548–561. DOI: 10.1016/j.jhazmat.2018.10.072
6. Rasin, P.; Ashwathi, A. V.; Basheer, S. M. et al. Exposure to Cadmium and its Impacts on Human Health: A Short Review. J. Hazard. Mater. Adv. 2025, 100608. DOI: 10.1016/j.hazadv.2025.100608
7. Lamm, S. H.; Boroje, I. J.; Ferdosi, H. et al. A Review of Low-Dose Arsenic Risks and Human Cancers. Toxicology 2021, 456, 152768. DOI: 10.1016/j.tox.2021.152768
8. Satarug, S.; Gobe, G. C.; Vesey, D. A. Multiple Targets of Toxicity in Environmental Exposure to Low-Dose Cadmium. Toxics 2022, 10 (8), 472. DOI: 10.3390/toxics10080472
9. Characterisation of Tattoo Inks Used in Australia; Australian Government, 2016.