National Geographic News, Reporting Your World Daily

Monday, November 23, 2009

Photo: Hair "Records" Where You've Been, Study Finds


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Two maps depict the average ratios of hydrogen isotopes (A) and oxygen isotopes (B) found in human scalp hair across the continental United States.

A new study has found that water molecules found in human hair closely resemble those in the tap water people drink.

Image courtesy PNAS/National Academy of Sciences, copyright 2008