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Reuters reports variations in hydrogen and oxygen isotopes found in hair can be matched to the regional tap water people have consumed, providing clues about where that person has been living. "You are what you eat and drink--and that is recorded in your hair," University of Utah geologist Thure Cerling said in a statement. For people who have long hair, that is quite a history! It works best on hair samples extracted from the head since hair grows continuously there. The study: Using tap water samples from 65 U.S. cities, Cerling and his research partner, University of Utah biology professor James Ehleringer, created a complex map of the regional differences in the hydrogen and oxygen isotopes of those water samples. To get the samples, Ehleringer's wife and a friend took a road trip to various towns in Southern, Central and Southwestern states where they also gathered hair samples from barbers. Meanwhile, Cerling's adult children were sent on a road trip of their own to the Northern United States. Samples were taken only from cities with 100,000 or fewer residents to ensure that the hair collected was from local residents and not tourists. "With the whole U.S. blanketed with samples of drinking water, we can see in the drinking water where the big gradients are," Cerling told Reuters. The results: The isotope patterns from the water samples matched the hair samples. "We were pleased that they did," Cerling said. Water we consume leaves an isotope signature in growing hair. That isotope signature is still visible even in people who drink bottled water, since they use tap water to make coffee and tea and to cook pasta, for example. The tool isn't perfect. Isotope concentrations vary in different cities' drinking water because of regional differences in rainfall and evaporation. That means researchers can readily tell the difference between Utah and Texas, but not necessarily between Chicago and Kansas City. Reuters reports that police in Salt Lake City, Utah are using the tool to help identify a possible murder victim. Cerling said the tool could also be used in anthropology and archaeology. The study findings were published in the journal Proceedings of the National Academy of Sciences. --From the Editors at Netscape | |||||||||||||
A new test conducted on a single strand of hair can tell scientists where in the United States that person has lived, a tool that could be extraordinarily valuable for crime investigators who are trying to identify a body or track criminals.
