Identifying the missing; utilising strontium isotopes for geolocation; finding the voice of Guatemala's forgotten

Austin, Ryan (2020) Identifying the missing; utilising strontium isotopes for geolocation; finding the voice of Guatemala's forgotten. PhD thesis, University of Lincoln.

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Identifying the missing; utilising strontium isotopes for geolocation; finding the voice of Guatemala's forgotten
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Item Type:Thesis (PhD)
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Abstract

From 1960-1996 Guatemala suffered an internal conflict where military forces waged war against the indigenous Mayan population. When the remains of individuals are found, identification efforts are often complicated, as families were displaced or disappeared, meaning reference samples often remain unfound. Consequently, the process of identifying individuals and returning them to their region of origin presents a challenge based on DNA evidence alone. Strontium isotope ratios in the body (such as from teeth, bone, and hair) can be used to provide region of origin and migration information during life. Therefore, the main aim of this thesis is to assess the degree to which strontium isotope ratios from the hair of modern living individuals can be used to distinguish between regions where individuals were reported missing. The literature has neglected to record modern human strontium isotope ratios from the country, which are influenced by modern dietary and water sources, a shortcoming this thesis overcomes. In this study, 129hair samples were collected from 10areas in Guatemala (Guatemala City, Villa Nueva, Chichicastenango, Lacama II, Santa Cruz, Rabinal, Coban, Chimaltenango, Jalapa, and Escuintla) were analysed for their strontium isotopic composition. The samples were leached with hydrochloric acid and subsequently digested in nitric acid before analysis of 87Sr/86Sr. Using inductively coupled plasma mass spectrometry (ICP-MS),an assessment was made in relation to whether external/leach (bathing water and atmospheric) or internal/digest (dietary) sources of strontium are suited to distinguish between such locations. Overall, with the 87Sr/86Sr of geographical regions grouped accordingly, from both field visits, a Kruskal-Wallis one-way analysis of variance was used to assess the degree of isotopic variation. All leach 87Sr/86Sr were found to be homogenous(p= 0.860). However, statistically significant differences were identified in digest 87Sr/86Sr between Guatemala City and Rabinal (p=0.001) and Guatemala City and Coban, respectively (p=0.010). The same conclusion for the latter comparison was gained through a small supplementary study conducted using thermal ionisation mass spectrometry (TIMS).While the theoretical application of such 87Sr/86Sr generated using TIMS to those involved in the internal conflict is complex, the significance of this study is that it demonstrates that strontium isotope ratios from modern, human samples can be used to differentiate between certain regions affected by the internal conflict. Informing our empirical understanding of the forensic potential of isotopes for provenancing applications within the country.

Keywords:Strontium Isotope Ratios, Hair, Guatemala, Inductively Coupled Plasma Mass Spectrometry, Thermal Ionisation Mass Spectrometry
Subjects:C Biological Sciences > C910 Applied Biological Sciences
Divisions:College of Science > School of Life Sciences
ID Code:49497
Deposited On:23 May 2022 10:00

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