Stable Isotope Provenance of Unidentified Deceased Migrants-A Pilot Study

In the global migration crisis, one of the challenges in the effort to identify deceased migrants is establishing their region of origin, which facilitates the search for ante mortem data to be compared with the post mortem information. This pilot study explores the potential of using stable isotope analysis to distinguish between individuals coming from West Africa and the Horn of Africa. Six individuals (four of known origin and two of unknown origin) were sampled. δ¹³C_{VPDB(keratin)}, δ¹⁵N_{VPDB(keratin)} and δ¹⁸O_{VSMOW(keratin)} of hair were analysed using Elemental Analyzers coupled with Isotope Ratio Mass Spectrometry (IRMS). δ¹⁸O_{VSMOW(carbonate)} and δ¹³C_{VPDB(carbonate)} of bone were analysed using GasBench II with IRMS, while ⁸⁷Sr/⁸⁶Sr composition was determined in bone and dental enamel using laser ablation multi-collector inductively coupled plasma mass spectrometry. The stable isotope compositions of the individual from the Horn of Africa differed from the other individuals. The differences found between ⁸⁷Sr/⁸⁶Sr of enamel and bone and between δ¹⁸O and δ¹³C in bone and hair reflect changes in sources of food and water in accordance with regionally typical migration journeys. The analysis of multiple stable isotopes delivered promising results, allowing us to narrow down the region of origin of deceased migrants and corroborate the information about the migration journey.