Hair analysis tells where people come from in U.S

Scientists said variations in hydrogen and oxygen isotopes found in hair could be matched to the regional tap water people drank, providing clues about where a person had been living in U.S., media reported Tuesday.

"In people with very long hair, you could get quite a long history," said University of Utah geologist Thure Cerling. The tool would work best on hair samples taken from the head because hair grows continuously there.

Cerling and University of Utah biology professor James Ehleringer developed an elaborate map that details regional differences in the hydrogen and oxygen isotopes based on tap water samples from 65 cities in the United States.

Cerling said drinking water left an isotope signature in the growing hair. Even people who drink bottled water still use tap water to make coffee or tea or cook pasta, he said. "You really do use a lot of local water in your everyday activities."

Police officers are already using the tool to help identify a possible murder victim.

Todd Park, a sheriff's detective in Salt Lake County, Utah, sent Ehleringer hair samples from a woman whose remains were found near the Great Salt Lake in October 2000.

An isotope analysis of the victim's hair showed she had moved around several states in the Northwest. The researchers planned to do an analysis of her teeth to see if the isotopes can reveal where she grew up when the teeth were forming.

The researchers said the work had generated a lot of interest from police, but Cerling said the tool could also be used in anthropology and archaeology. "I also think it will have some interesting applications in wildlife conservation," he said.