Tap Water Leaves Forensic Clue in Hair

Finding May Help Solve Murder Cases, Researchers Report

By Miranda Hitti
WebMD Health News

Reviewed By Louise Chang, MD

Feb. 25, 2008 -- Your hair may reveal where in the U.S. you live. Tap water leaves telltale clues about regions, new forensic research shows.

Scientists have developed a test that predicts where in the U.S. a person lives based on traces of hydrogen and oxygen in hair samples.

"Police are already using this to reconstruct the possible origins of unidentified murder victims," University of Utah biologist James Ehleringer, PhD, says in a news release.

Ehleringer's team collected hair samples from barbershops in 65 U.S. cities. They also collected samples of local tap water.

Levels of hydrogen and oxygen in the hair samples were in sync with traces of hydrogen and oxygen in local tap water. "We have found significant variations in hydrogen and oxygen isotopes in hair and water that relate to where a person lives in the United States," says Ehleringer.

The researchers considered the fact that some people may drink bottled water which came from another part of the country, and the fact that people don't just eat locally grown foods. The test still worked.

The test may also prove useful for gathering dietary information, note Ehleringer and colleagues.

Their findings appear in the Feb. 26, 2008 edition of Proceedings of the National Academy of Sciences.

SOURCES: Ehleringer, J. Proceedings of the National Academy of Sciences, Feb. 26, 2008; vol 105: pp 2788-2793. News release, Proceedings of the National Academy of Sciences. News release, University of Utah.

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