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The determination of an individual's geographic origin is an essential aspect of forensic investigations. When primary identifiers cannot be used to make a positive identification, isotope analysis can be utilized to provide new leads. Modern reference data are essential for accurate interpretation of human isotopic data in terms of diet and origin. This article presents Sr-O-C-N-H isotope data of modern individuals (hair, dental enamel, and dentine collagen) and drinking water from the Netherlands. The δ 15 N values of human hair fall within the range of values observed worldwide and cannot be utilized to differentiate from other countries. Distinct disparities in the hair δ 13 C are evident between European countries and other regions, making it possible to exclude the Netherlands as a region of origin. Comparing Dutch dental isotope data to those of other nations has proven difficult due to the limited availability of reference data. The same limitation applies to tap water δ 2 H data., Competing Interests: The authors declare no competing interests., (© 2024 Published by Elsevier Inc.)

Deceased undocumented border crossers are some of the most difficult individuals to identify due to the inability to narrow down the region of origin and therefore to obtain family reference samples for DNA comparison. The isotopic compositions of various body tissues have been demonstrated to be useful biomarkers for tracking locations and movements to aid in the identification of human remains. This study closes the large spatial gap of available 87 Sr/ 86 Sr ratios from North America in tap water and presents the first 87 Sr/ 86 Sr human tissue-based ratios from Mexico. The 101 hair samples from 32 locations in Mexico range in 87 Sr/ 86 Sr ratios from 0.70424 to 0.71613 (ΔSr max-min =0.01189). Furthermore, 151 tap water samples from 51 locations range between 0.70404 to 0.71385 (ΔSr max-min =0.00981). Overall, small variations in the hair and tap water samples collected from individual locations were recorded (ΔSr max-min =0.00041 and 0.00034 respectively). Despite the fact that Mexico is one of the largest bottled water consumers in the world, the 87 Sr/ 86 Sr ratios of human hair and tap water correlated strongly (R 2 =0.87 for location averages and R 2 =0.80 when using individual data points). These data represent a valuable resource for identifying the provenance of human remains., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The analysis of strontium isotope ratios in human dental enamel has become important in the fields of archaeological and forensic science for determining provenance and hence mobility. The prerequisite for the approach relies on a correlation between dietary Sr intake and the underlying local geology. This premise is brought into question for anthropological forensic investigations by the increasing globalisation of food supply, the establishment of nation-wide or international supermarket chains, and increasing urbanisation. To better understand the processes that cause spatial variation of Sr isotope ratios in the modern environment, this study determines the range of 87 Sr/ 86 Sr ratios in the modern Dutch environment based on 296 modern human dental enamel and tap water samples. Tap water 87 Sr/ 86 Sr from the Netherlands range from 0.70837 to 0.71278 (ΔSr max - min  = 0.0044) and modern human enamel from 0.70847 to 0.70995 (ΔSr max - min  = 0.0015). The 87 Sr/ 86 Sr ratios of tap water are predominantly determined by the underlying bedrock geology at the sampling point. In contrast, the human enamel data record an insignificant, weak correlation with water supply or local geology. Hence, the main principle behind the application of 87 Sr/ 86 Sr as a proxy for mobility appears invalid in the modern globalised Dutch context. The range of 87 Sr/ 86 Sr in modern Dutch humans that can be used for anthropological forensic investigations is between 0.7085 and 0.7100 (n = 153), with 98.0% of individuals between 0.7088 and 0.7099., Competing Interests: Declaration of competing interest The authors have declared that no competing interests exist., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)