Limits and possibilities in the geolocation of humans using multiple isotope ratios (H, O, N, C) of hair from east coast cities of the USA

Abstract

We examined multiple natural abundance isotope ratios of human hair to assess biological variability within and between geographic locations and, further, to determine how well these isotope values predict location of origin. Sampling locations feature differing seasonality and mobile populations as a robust test of the method. Serially-sampled hair from Cambridge, MA, USA, shows lower δ(2)H and δ(18)O variability over a one-year time course than model-predicted precipitation isotope ratios, but exhibits considerable differences between individuals. Along a ∼13° north-south transect in the eastern USA (Brookline, MA, 42.3 ° N, College Park, MD, 39.0 ° N, and Gainesville, FL, 29.7 ° N) δ(18)O in human hair shows relatively greater differences and tracks changes in drinking water isotope ratios more sensitively than δ(2)H. Determining the domicile of humans using isotope ratios of hair can be confounded by differing variability in hair δ(18)O and δ(2)H between locations, differential incorporation of H and O into this protein and, in some cases, by tap water δ(18)O and δ(2)H that differ significantly from predicted precipitation values. With these caveats, randomly chosen people in Florida are separated from those in the two more northerly sites on the basis of the natural abundance isotopes of carbon, nitrogen, hydrogen, and oxygen.

Determinants of blood water δ18O variation in a population of experimental sheep: Implications for paleoclimate reconstruction

“…This utilization rate shifts the phase of isotopic oscillations for Bedford water by approximately 6 months compared to precipitation, so that Bedford drinking water δ 18 O values are not low in winter and high in summer, as would be predicted from precipitation. This phenomenon is consistent with observations of drinking water in the region (Reynard et al , 2016), and is slightly amplified in the Kohn model, as a result of higher predicted atmospheric water vapor intake during humid summer months. However, the model-predicted seasonal variation is anticorrelated with the fluctuations in measured blood δ 18 O values, which we examine in the Discussion.…”

WITHDRAWN: A global carbon and nitrogen isotope perspective on modern and ancient human diet

“…A parallel body of stable isotope research has been conducted on the stable isotope composition of the tissues of contemporary humans [15][16][17][18] . This research has mostly focused on non-invasive nail and hair keratin, to examine the physiological processes in the human body, to deduce the recent movements of individuals 19 , or to identify locations for repatriation of human remains 20 . Substantial effort has been directed towards developing a spatial understanding of the controls on the stable isotope composition of modern human tissues, mostly as a consequence of the potential forensic application of this type of research 18,21 .…”

Stable isotope relationships between apatite phosphate (δ18O), structural carbonate (δ18O, δ13C), and collagen (δ2H, δ13C, δ15N, δ34S) in modern human dentine

“…Studies on δ 18 O values in tooth apatite of contemporary humans confirm their relationship to the oxygen isotope ratios of drinking water, tap water, or precipitation . In addition, the δ 2 H and δ 18 O values of modern human hair and nails are connected to precipitation . In human hair, 27% of the oxygen atoms and 36% of the hydrogen atoms are derived from drinking water .…”

“…[12][13][14][16][17][18][19][20] In addition, the δ 2 H and δ 18 O values of modern human hair and nails are connected to precipitation. 3,[21][22][23][24] In human hair, 27% of the oxygen atoms and 36% of the hydrogen atoms are derived from drinking water. 25 As previously shown by the relationship between keratin δ 2 H and bone collagen δ 2 H values, 3 the same may be supposed for dentine collagen δ 2 H values.…”