BioEd Online

Leslie Wagner, an undergraduate at Northern Arizona University, got a tattoo her freshman year. Later, wondering what causes tattoos to fade, she discovered that no one really knows what is in the ink, or whether the ingredients differ from brand to brand.

Perusing dermatology journals, she found that people from time to time have bad reactions to the ink in their tattoos, particularly when getting MRI scans (the magnetic fields involved sometimes seem to heat the ink beneath the skin). And further investigation showed that the inks are not subject to any safety regulations, at least not in the US.

So Wagner joined up with similarly tattooed Haley Finley-Jones, also at Northern Arizona University in Flagstaff, to examine the question. Finding funding was hard, says Jones. "A lot of people thought 'oh, just college students wanting to study tattoos'," she says. "Until they found out that the FDA doesn't regulate it."

Finally, they got the funds, and with the help of an advisor put several different colours and brands of tattoo ink through three different tests to work out what was in them. They found that each colour and each brand has completely different ingredients.

They were also startled by the high levels of lead in some of the inks, as well as the presence of lithium. And the blue inks had so much copper in them they went right off the scale.

The students are leaving it to others to work out what this all means for human health. "We're really not biologists," Wagner says. Still, they stand by their own tattoos, pictures of which grace their poster at the American Chemical Society meeting in San Diego this week.

"I'm not really afraid," says Wagner. "I mean, millions of people have tattoos, and most of them are fine."

Finley-Jones plans to continue the work next year - without Wagner, who is graduating. She plans to characterize the components of the inks more precisely, and extend her studies to include powdered and novelty inks, like the UV-sensitive kind that is now on the market for those who want glow-in-the-dark tattoos.