Sr–Pb isotope differences in pre- and post-burial human bone, teeth, and hair keratin:implications for isotope forensics

The isotopic signatures of human tissues can provide valuable information on geographic origin for medicolegal investigations involving unidentified persons. It is important to understand the impact of diagenetic processes on isotopic signatures, as alterations could result in incorrect estimation of geographic origin. This study examines alterations in isotope signatures of different tissues of five human body donors studied throughout decomposition at the Forensic Anthropology Research Facility (FARF), San Marcos, TX. Two body donors were buried, two were placed in open pits, and one was first allowed to naturally mummify and then buried. Remains were recovered after a period of 7–34 months. The preplacement and post-recovery Sr–Pb isotope data of scalp hair, bone (iliac and tibia), and tooth enamel and dentine were compared. The hair samples record significant shifts in Sr-Pb isotope compositions, with hair keratin Pb isotope composition shifting towards the Pb signature of local soil samples. Hair keratin Sr isotope compositions were altered by the burial environment and possibly also by the lab sample cleaning method. The spongy iliac bone samples show inconsistencies in the recoverability of the preplacement Sr–Pb isotope signatures. The post-placement signatures of the buried donors show slight elevation over preplacement signatures. The post-placement signatures of donors placed in open pits are significantly elevated. The tibia and dental samples record the most consistent isotopic data with the least alteration. These more densely mineralised elements show good recoverability of the preplacement isotope signatures in burials and open pits and are thus deemed better targets for forensic investigative purposes.</p

Diet and urbanisation in medieval Holland. Studying dietary change through carious lesions and stable isotope analysis

In the late medieval period, Holland experienced substantial socio-economic change. While the region was largely undeveloped prior to 1200 CE, the period after was characterised by extensive urbanisation and flourishing international trade, changes that would have impacted many aspects of life. This paper investigates the effect of these changes on diet by comparing skeletal collections from the early/central medieval rural village of Blokhuizen (800–1200 CE) to the late medieval urban town of Alkmaar (1448–1572 CE) using a combination of the prevalence and location of carious lesions (nteeth = 3475) and stable carbon and nitrogen isotope data (n = 50). Results show that the urban Alkmaar population had a significantly higher caries frequency (7.4% vs. 16.1%), starting at a younger age. Moreover, Alkmaar had significantly more approximal caries. These results point to increased consumption of cariogenic products, such as sugars and starches, by the urban citizens. Dietary differences are also demonstrated by the stable isotope data. Alkmaar individuals have significantly enriched δ15N ratios and more variable δ13C ratios compared with rural Blokhuizen. The elevated δ15N values may be due to increased consumption of fish or animals such as omnivorous pigs and chickens. The combination of caries and isotopic data points to clear changes in diet suggesting that urban individuals in the late medieval period had a substantially different diet compared with early rural inhabitants from the same area. Specifically, an increase in market dependence, availability of international trade products, and the growth of commercial fishing in the late medieval period may have contributed to this dietary shift. Future research should include a late medieval rural population to better understand the effects of late medieval socio-economic developments outside of the urban environment. This study demonstrates that the integration of palaeopathology and stable isotopic research provides a more complete understanding of dietary changes in medieval Holland

Reprint of: The effects of decomposition and environment on antemortem H-Pb-Sr isotope compositions and degradation of human scalp hair:Actualistic taphonomic observations

Multi-isotope analysis (e.g., Sr-Pb-O-H-C-N) of human scalp hair is routinely used in forensic investigations of human remains to constrain the geographic origin of unidentified bodies, and to investigate antemortem mobility patterns. However, while it is known that postmortem processes can affect the preservation of, or even overprint, the biogenic isotopic signatures in hair, the speed and nature of these processes have rarely been studied. This study investigates the effects of decomposition and environment on the H-Pb-Sr isotope compositions of human hair as well as the relationship between structural hair shaft degradation and isotopic signature change over time. Human scalp hair samples from four body donations were collected at different stages throughout gross body decomposition. The willed-donated bodies were placed to decompose outdoors at the Forensic Anthropology Research Facility (FARF) at Texas State University. Hair fibres from two of the donations were examined using scanning electron microscopy (SEM) and high-resolution light microscopy (HRLM). Chemical and microbiological degradation of hair fibres occurred rapidly after placement of the body outdoors. Measurements of scalp hair isotopic composition demonstrated that H-Pb-Sr isotope ratios were altered within days after environmental exposure, presumably by deposition, leaching and/or exchange with the local bioavailable soil, and vapour. The degree of physical hair degradation and changes in H-Pb-Sr isotope composition were not correlated. We conclude that antemortem isotopic H-Pb-Sr isotope ratios are difficult to recover in hairs derived from decomposing whole bodies

Beyond isolation: understanding past human-population variability in the Dutch town of Oldenzaal through the origin of its inhabitants and its infrastructural connections

This study presents a first attempt to assess the mechanisms and potential controls behind past residential mobility through the integration of isotopic data from human inhumations and spatial infrastructural information pertaining to the settlement containing these inhumations. Strontium (87Sr/86Sr) and oxygen (δ18OPDB) isotope data are derived from 200 (post)medieval individuals from the town of Oldenzaal in the present-day Netherlands. Reconstructions of historical route networks show that Oldenzaal was well-connected interregionally throughout the Middle Ages and early-modern times (ca. AD 800–1600). Although the working hypothesis was that in the past a high degree of spatial connectivity of settlements must have been positively related to a highly variable geographical origin of its inhabitants, the isotopic data from Oldenzaal indicate a population characterized by a low variability in terms of their origin. This unexpected result may be caused by (a combination of) various factors, related to (1) biases in the isotopic dataset, (2) interpretative limitations regarding the results of isotopic analyses and (3) the impact of broader socio-cultural factors that cannot be traced through isotopic analyses, such as infrastructural connectivity, socio-economics and political factors. The human oxygen isotope dataset presented here provides a first step towards a δ18OPDB reference dataset, against which future samples can be compared without the need to convert the data. This paper establishes that although in archaeology a biomolecular approach potentially provides a detailed reconstruction of the development of past populations in terms of palaeodemography and geographical/cultural origin, such studies should be performed in a transdisciplinary context in order to increase the understanding of the wider controlling factors of past population change

Actualistic experimental replication of a small-sized mass grave

In May 2021 a mass grave with six body donors, a control mass grave without donors, as well as three individual graves and one (empty) individual control grave, were placed at the Forensic Anthropology Research Facility (FARF), the human taphonomy facility managed by FACTS. The graves are monitored in situ for 18 months, after which they will be excavated. Human tissue and environmental (soil, vegetation) samples were collected prior to burial. Soil samples, volatile organic compounds, and remote and geophysical data will be collected from the graves at intervals throughout the experiment. Temperature, moisture and electrical conductivity are monitored by soil sensors placed in the graves. The body donors and graves were documented in 3D using CT scanning and photogrammetry; the 3D data generated in this experiment will provide research-based educational materials that can be used to train forensic science and anthropology students and mass grave investigators. They will be used to develop a 3D virtual training tool for the documentation and excavation of mass graves, which will be made available to international humanitarian organizations involved in mass grave investigation. The project will generate recommendations regarding optimal methods of (remote) detection, rapid and accurate 3D documentation, human tissue sampling procedures and isotopic and biomolecular methods to aid identification. The initial results of the overall project as well as first recommendations for sampling and analysis will be presented

The effects of decomposition and environment on antemortem H-Pb-Srisotope compositions and degradation of human scalp hair : Actualistic taphonomic observations

Multi-isotope analysis (e.g., Sr–Pb–O–H–C–N) of human scalp hair is routinely used in forensic investigations of human remains to constrain the geographic origin of unidentified bodies, and to investigate antemortem mobility patterns. However, while it is known that postmortem processes can affect the preservation of, or even overprint, the biogenic isotopic signatures in hair, the speed and nature of these processes have rarely been studied. This study investigates the effects of decomposition and environment on the H–Pb–Sr isotope compositions of human hair as well as the relationship between structural hair shaft degradation and isotopic signature change over time. Human scalp hair samples from four body donations were collected at different stages throughout gross body decomposition. The willed-donated bodies were placed to decompose outdoors at the Forensic Anthropology Research Facility (FARF) at Texas State University. Hair fibers from two of the donations were examined using scanning electron microscopy (SEM) and high-resolution light microscopy (HRLM). Chemical and microbiological degradation of hair fibers occurred rapidly after placement of the body outdoors. Measurements of scalp hair isotopic composition demonstrated that H–Pb–Sr isotope ratios were altered within days after environmental exposure, presumably by deposition, leaching and/or exchange with the local bioavailable soil, and vapor. The degree of physical hair degradation and changes in H–Pb–Sr isotope composition were not correlated. We conclude that antemortem isotopic H–Pb–Sr isotope ratios are difficult to recover in hairs derived from decomposing whole bodies