Tracking human travel using stable oxygen and hydrogen isotope analyses of hair and urine

The stable oxygen and hydrogen isotope compositions of organic samples are increasingly being used to investigate patterns of animal migration. Relatively few studies have applied these techniques to modem humans, despite a variety of potential forensic applications. We analyzed drinking water and food at two geographic locations, East Greenbush, New York (USA) and Fairbanks, Alaska (USA), with different delta O-18 and delta D values for precipitation and tap water. Foods varied widely in measured delta O-18 and delta D values, but not systematically by purchase location. We measured delta O-18 and 813 values of scalp hair from five residents at each location. We used a mixing model to establish the proportion of oxygen and hydrogen in head hair derived from drinking water (-27% and -36%, respectively). Finally, we analyzed the 3180 and delta D values of facial hair and urine from a subject who traveled from Fairbanks to East Greenbush, on to the UK and back to Fairbanks. Urine 3180 and SD values responded immediately and strongly to travel-related change in drinking water, and were well described by a single-pool turnover model. Beard hair 8180 values tracked changes in urine 8180 closely, and oscillated between the values for the resident populations in both locations. In contrast, beard hair 313 values did not track changes in urine delta D as well, and retained a signature of the traveler's permanent residence. Our findings show that the 3180 and delta D values of urine and facial hair (specifically 3180) can provide a record of the geographical movements of humans. Copyright (C) 2007 John Wiley & Sons, Ltd.