ScienceShot: This Beer Knows Where You've Been

Have you lapped up any lemonade in Laramie? Downed a daiquiri in Denver? Knocked back a microbrew in Boston? New research suggests that your visits to such places can be tracked by analyzing chemical traces in your hair. That's because water molecules differ slightly in their isotope ratios depending on the minerals at their source. In a study published in the current issue of The Journal of Agricultural and Food Chemistry, researchers found that water samples from 33 cities across the United State could be reliably traced back to their origin based on their isotope ratios. And because the human body breaks down water's constituent atoms of hydrogen and oxygen to construct the proteins that make hair cells, those cells can preserve the record of a person's travels. Such information could help prosecutors place a suspect at the scene of a crime, or prove the innocence of the accused.

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