Nuclear smuggling

Scientists have found a way to spot nuclear smugglers—by looking at their nail clippings

Even if you remove yourself from the scene of the crime, you can’t always take the crime scene out of you.

As our nails and hair grow, they carry clues about our health: medical professionals can examine them for signs of illness or poor nutrition. They can also contain traces of the chemicals we’ve touched or ingested long ago—including enriched uranium used in nuclear power or weapons. Researchers from the University of Missouri have demonstrated (paywall) that different ratios of the radioactive element in hair and nails can distinguish people who have handled the material recently from those who haven’t.

Uranium is a naturally occurring element found in food and water in amounts that are safe for human consumption. In its natural state, uranium is found in the isotopes U-235 and U-238; the numbers indicate the amount of neutrons in each atom. Because uranium is relatively massive for an atom, its atom breaks down over time, which gives off energy.