Resident and Nonresident Fingernail Isotopes Reveal Diet and Travel Patterns

Global travel has increased, and having a diagnostic tool to distinguish residents from visitors would be valuable. This study examined stable isotope biomarkers of fingernail tissues of resident (n = 26) and nonresident (n = 22) participants in Salt Lake City (SLC), UT, from 2015 to 2016. The purpose of this research was to determine whether fingernail isotopes could be used for reconstructing geolocation movements and to examine the convergence in nonresident fingernail isotopes to that of the resident signal following their arrival to SLC. Resident isotope values defined a baseline to make comparisons to. Initial nonresident hydrogen and oxygen isotope values were correlated with precipitation isotopes of their prior location. Fingernail isotope turnover rates were rapid and nonresident isotopes were indistinguishable from residents after ~71-90 days. The results of our study highlight the utility of stable isotope measurements of fingernail clippings to examine travel history reconstruction that could aid in identification of human remains.