London, Sep 13 (IANS): If you are planning to ink a tattoo, think twice. According to a study, the components in the tattoo ink transports various pigments and toxic element impurities inside the body in micro and nano-particle forms to the immune system, which could have an unknown effect on the body.

When a tattoo is etched on the body, its ink gets deposited via a needle below the skin, where the ink particles remain permanently.

The findings showed that potential impurities in the colour mixture applied to the skin travels to the lymph nodes -- small, bean-shaped glands throughout the body and is an important part of the immune system.

Most tattoo inks include preservatives and contaminants like nickel, chromium, manganese or cobalt -- associated with high risk of cancer.

"When someone wants to get a tattoo, they are often very careful in choosing a parlour where they use sterile needles that haven´t been used previously," said Hiram Castillo, scientist at the European Synchrotron Radiation Facility (ESRF) in France.

"No one checks the chemical composition of the colours, but our study shows that maybe they should," Castillo added.

One common ingredient used in tattoo inks is titanium dioxide (TiO2) -- a white pigment usually applied to create certain shades when mixed with colourants.

For the study, published in the journal Scientific Reports, the team conducted chemical analysis of the inks and their degradation products in vitro. They located TiO2 at the micro and nano range in the skin and the lymphatic environment.

They found a broad range of particles with up to several micrometres in size in human skin but only smaller (nano) particles transported to the lymph nodes.

This may lead to chronic enlargement of the lymph node and lifelong exposure, the researchers warned.

Pigments from tattoo that travel to the lymph nodes in a nano form implies that they may not have the same behaviour as the particles at a micro level.

"And that is the problem: we don't know how nanoparticles react," explained Bernhard Hesse, another scientist at the ESRF.