Hydrogen isotope systematics of hair:: archeological and forensic applications

The hydrogen isotope systematics of hair have been explored and several applications demonstrate the type of information that can be recovered from archeological and forensic hair samples. Experiment with modern hair demonstrate that sources of protein-based hydrogen in keratin are food and water. On the basis of a deuterium-enriched drinking study, it was found that similar to 31% of hydrogen in human hair is derived from ingested water. At least 9% of total hydrogen in human hair is isotopically exchangeable with water or water vapor at 25 degreesC. Nearly complete exchange occurs in a matter of hours. The deltaD value of body water is approximately 17 +/- 10parts per thousand (n=7) more negative than human hair, although there is much scatter in data for modern hair, which is clearly related to variability of the isotopic composition of ingested food and water. Archeological hair samples were analyzed from (i) a 370 year old Incan mummy sacrificed at 5300 m altitude in Argentina (Geoarchaeology 14 (1999) 27) and (ii) from a Woolly Mammoth from Siberia. High spatial resolution data along the length of hair from the mummy indicate seasonal variations in carbon, nitrogen and hydrogen isotope ratios. No hydrogen isotope anomalies are seen in the youngest hair at the base of the scalp, indicating that the individual probably lived at similar to 1600 m, and spent less than a week at high altitudes before death. The mammoth also preserves a seasonal signal, suggesting hair growth rates of similar to 33 cm/year, faster than human hair, but slower than horse tail hair. The limited isotopic range across seasons for the mammoth is consistent with a north-south migration on the order of 1000 km. (C) 2003 Elsevier Ltd. All rights reserved.