Investigating Residential History Using Stable Hydrogen and Oxygen Isotopes of Human Hair and Drinking Water

The relationship between isotopic signals in human hair and geographic region has potential forensic applications for identifying unknown individuals' place of recent residence. This study analyzes δ(2) H and δ(18) O isotopes in residential tap water and bulk hair samples from 17 volunteers representing 12 locations in Ontario, Canada. There is a strong correlation (R(2) = 0.9) between δ(2) H and δ(18) O values of the water samples. In contrast, the δ(2) H and δ(18) O values of the hair samples are weakly correlated (R(2) = 0.3), and the greater variability in the data is linked to dietary factors. This study demonstrates that the δ(2) H and δ(18) O values of hair and drinking water can be used to help identify potential place of residence in forensic cases, particularly in relation to proximity to large bodies of water such as the Great Lakes, but interpretations are complicated by the contribution of both water and diet to δ(2) H and δ(18) O values in hair.