Application of Stable Isotope Forensics for Predicting Region of Origin of Human Remains From Past Wars and Conflicts

Abstract

The application of stable isotope analysis has provided novel approaches for provenancing unidentified human remains from forensic contexts. Stable isotope ratios measured in human tissues provide a record of the foods consumed during life as well as the geographic location where drinking water or food was obtained. This study begins with an overview of the application of stable isotope analysis for provenancing human remains, followed by three cases that illustrate how chemical signatures in bone reflect a probable region of origin. Using stable carbon and nitrogen isotopes of human bone, we test whether human skeletal remains recovered by the Joint POW/MIA Accounting Command‐Central Identification Laboratory (JPAC‐CIL, or CIL) reflect a geographic origin within North America or Asia. Stable carbon and nitrogen isotopes of human bone collagen and stable carbon isotopes of bone apatite reflect consumption of food resources that are expected to vary between world regions due to cultural dietary differences. Based on the isotopic differences, a testable hypothesis of geographic origin can be applied, determining if the remains are more likely of a U.S. service person or of an indigenous local. We believe that this approach can provide useful information for narrowing search parameters in unidentified persons cases; can contribute to human rights cases where an unknown individual is thought to originate from a different geographic area; and, in human remains cases of unknown geographic provenience, can determine whether a person is local or nonlocal.

Using Carbon, Oxygen, Strontium, and Lead Isotopes in Modern Human Teeth for Forensic Investigations: A Critical Overview Based on Data from Bulgaria

“…Valenzuela et al reported significantly lower δ 13 C in hair from European individuals compared to US individuals. Similarly, Bartelink et al reported significantly lower δ 13 C in human bone collagen from Asian individuals compared to US individuals. The differences in δ 13 C are ultimately related to the relative proportion of C3 vs C4 plants in the regional diet.…”

Stable Isotopes Trace the Truth: From Adulterated Foods to Crime Scenes

“…While carbon isotopes have been used to detect food adulteration, nitrogen isotopes are commonly analyzed to distinguish organic from nonorganic fertilizers used in the production of vegetable crops (Chesson et al 2014). Vegetables raised with synthetic fertilizers often have nitrogen isotope ratios of between +3‰ and +5‰; plants raised on organic fertilizers are expected to have higher nitrogen isotope ratios between +10‰ and +20‰.…”

“…As war-zone human remains are occasionally recovered in Vietnam, the bone tissues are fi rst analyzed isotopically to determine their carbon isotope ratios. In these cases, differences in carbon isotope ratios in bone tissues of remains from these regions are applied to determine if a set of remains are more likely to be from a US serviceperson or an indigenous local (Bartelink et al 2014). …”

“…Furthermore, even slight differences in how a chemical is manufactured or the substitution of ingredients from one source of raw materials to another can be recorded in the isotope ratios of organic molecules of the product itself. And this can lead to useful insights into the origins, authenticity, and verification of a food product (Chesson et al 2014). …”

“…The subtle, but signifi cant, changes in the hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope compositions of the water we drink and the foods we eat become refl ected in our hair (Valenzuela et al 2012;Nechlich 2015), which can thereby record geographic and dietary information (Ehleringer et al 2008;Thompson et al 2014;Chesson et al 2014). Human hair becomes a linear recorder of our diets and geographic origins; this leads to applications that include the investigation of historical practices, modern dietary patterns, and even forensic cases (Ehleringer et al 2008;Thompson et al 2014).…”