Traveling There and Back Again: A Fingernail's Tale

This study focuses on the examination of stable isotope biomarkers in human fingernails of travelers who ventured away from Salt Lake City, UT and subsequently returned. Here, we describe three case studies examining: individual travelers (n = 4), paired travelers (n = 2), and a traveler (n = 1) who repeatedly left and returned. Our case studies examined the influences of dietary and drinking water inputs on fingernail stable isotope profiles for reconstructing travel histories. Stable isotope data were compared with theoretical and predictive models that laid the groundwork for anthropological and forensic geospatial reconstruction of travel histories. Drinking water inputs strongly influenced stable isotope profiles and the patterns observed were consistent with reported travel histories. Finally, observed fingernail stable isotope ratio data were consistent with modeled rates of stable isotope turnover and transition to expected values for the new environment. The results of our study further support the use of fingernail tissues for travel history reconstruction.