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Fu Y, Zhang R, Rong S, Wu Y, Wu Y, Ya M. A methodological review of compound-specific radiocarbon analysis for polycyclic aromatic hydrocarbons in environmental matrices. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 350:124050. [PMID: 38677454 DOI: 10.1016/j.envpol.2024.124050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 04/29/2024]
Abstract
Identifying the sources of polycyclic aromatic hydrocarbons (PAHs) in complex environmental matrices is essential for understanding the impact of combustion-related human activities on the environment. Since the turn of the century, advances in analytical capability and accuracy of accelerator mass spectrometry (AMS) have made it possible to accurately determine the source apportionment of PAHs based on their radiocarbon (14C) mass conservation. This also allows us to trace the environmental transport processes of PAHs from the perspective of molecular 14C. However, natural environmental matrices have very low concentrations of PAHs (ppb to ppm level). To meet the requirements of carbon weight for 14C measurement by AMS, trace PAHs in complex environmental matrices must be enriched thousands of times, and then higher purity individual PAH molecules should be obtained through a series of complex purification procedures. Therefore, the technical difficulty is the main challenge in expanding the application of compound-specific 14C analysis in environmental science. This article reviews the detailed pretreatment procedures for 14C measurement of specific PAHs, including sample enrichment, extraction and purification of aromatic components, preparation of compound-specific PAHs by preparative capillary gas chromatography, graphitization of samples with ultra-small carbon content, and relevant quality control and assurance procedures. This study aims to help environmental geoscientists understand the technical process of 14C analysis of PAHs and inspire new scientific questions related to environmental science. To our knowledge, this is the first comprehensive review of the technical method of compound-specific 14C analysis for PAHs.
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Affiliation(s)
- Yu Fu
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, China; State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China
| | - Rui Zhang
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, China; State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China
| | - Shaopeng Rong
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, China
| | - Yuling Wu
- School of Marine Sciences, Nanjing University of Information Science & Technology, Nanjing 210044, China
| | - Ying Wu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China
| | - Miaolei Ya
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China.
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2
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Lichtfouse E. Single Sample Molecular Chronology. Acc Chem Res 2024. [PMID: 38295306 DOI: 10.1021/acs.accounts.3c00665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
ConspectusThis Account presents a new discipline, single sample molecular chronology (SSMC), which studies the relative age of an individual compound occurring in several temporal pools of a single sample in complex media. Geochemists have analytically observed for a long time that several pools of the same compound, e.g., a hydrocarbon or a pesticide, can be isolated from the same sample, e.g., a sediment or a soil, to yield a free compound pool obtained by solvent extraction and then a bound compound pool after treatment of the solid residue and further extraction. Yet the study on the significance of these pools has been limited due to the inherent lack of criteria to clearly distinguish the same compound present in various pools, and, as a consequence, the existence of these pools has been criticized as resulting from a default of extraction during analytical fractionation. Our breakthrough was to distinguish isotopically several temporal pools of a plant-derived C31 n-alkane in a soil sample containing naturally 13C-labeled carbon and then to set up a method, 13C-relative dating, to calculate the relative age of these temporal pools. We observed wide differences in the relative age of the C31 n-alkane in temporal pools of a single soil sample, ranging from -6.7 years for a soil humin-bound homologue to +25.1 years for the free homologue in the coarser soil particle-size fraction. Individual compounds can thus be used as molecular clocks to determine the relative age of temporal pools from the same sample. Moreover, our findings represented the first unambiguous proof that bound compounds are cycling slower and are somehow protected in a complex organo-mineral matrix, key information for the mechanism of carbon sequestration. SSMC could be developed in all disciplines of physical, biological, and environmental sciences manipulating complex media, to study the history of individual compounds. This chronochemistry should provide new information about the origin and transformation of individual compounds in biogeochemical systems. For example, historical information on drugs or pollutants encapsulated in temporal pools of a living organism would bring about critical new knowledge about the mechanisms of disease development. Investigations require isotope tracing using any isotope in natural or artificial abundance. Methods to separate temporal pools are suggested.
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Affiliation(s)
- Eric Lichtfouse
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, 28 Xianning West Road, Xi'an, Shaanxi 710049, P. R. China
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3
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Geddes da Filicaia E, Evershed RP, Peggie DA. Review of recent advances on the use of mass spectrometry techniques for the study of organic materials in painted artworks. Anal Chim Acta 2023; 1246:340575. [PMID: 36764767 DOI: 10.1016/j.aca.2022.340575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 10/28/2022] [Accepted: 10/29/2022] [Indexed: 11/06/2022]
Abstract
The study of painted artworks using scientific methods is fundamental for understanding the techniques used in their creation and their appropriate conservation. The ethical constraints involved in the handling of, and sampling from, these objects has steered recent developments in the field of Heritage science towards a range of new non-invasive/non-destructive spectroscopic techniques capable of providing important insights into their elemental or bulk chemical compositions. Due to the inherent complexities of heritage artefacts, however, their organic components are especially difficult to study in this way and their identification and degradation pathways are thus often best investigated using mass spectrometric (MS) techniques. The versatility, sensitivity and specificity of MS techniques are constantly increasing, with technological advances pushing the boundaries of their use in this field. The progress in the past ten years in the use of MS techniques for the analysis of paint media are described in the present review. While some historical context is included, the body of the review is structured around the five most widely used or emerging capabilities offered by MS. The first pertains to the use of spatially resolved MS to obtain chemical maps of components in cross-sections, which may yield information on both inorganic and organic materials, while the second area describes the development of novel sample preparation approaches for gas chromatography (GC)-MS to allow simultaneous analysis of a variety of components. The third focuses on thermally assisted analysis (either with direct MS or coupled with GC-MS), a powerful tool for studying macromolecules requiring zero (or minimal) sample pre-treatment. Subsequently, the use of soft ionisation techniques often combined with high-resolution MS for the study of peptides (proteomics) and other macromolecules (such as oligosaccharides and triglycerides) is outlined. The fifth area covers the advances in radiocarbon dating of painting components with accelerator MS (AMS). Lastly, future applications of other MS techniques to the study of paintings are mentioned; such as direct analysis in real time MS (DART-MS) and stable isotope ratio MS (IRMS). The latter, having proven its efficiency for the study of lipids in archaeological artefacts, is envisioned to become a valuable tool for this area, whereas DART-MS is already being utilised to study the surface composition of various museum objects. Rapid technological advances, resulting in increased sensitivity and selectivity of MS techniques, are opening up new approaches for paintings analysis, overcoming the fundamental hurdle of sample size available for destructive analysis. Importantly, while the last decade has seen proteomics applications come to the fore, this review aims to emphasise the wider potential of advanced MS techniques for the study of painting materials and their conservation.
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Affiliation(s)
- Eugenia Geddes da Filicaia
- Scientific Department, National Gallery, Trafalgar Square, London, WC2N 5DN, UK; Organic Geochemistry Unit, Bristol Biogeochemistry Research Centre, School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1T, UK.
| | - Richard P Evershed
- Organic Geochemistry Unit, Bristol Biogeochemistry Research Centre, School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1T, UK
| | - David A Peggie
- Scientific Department, National Gallery, Trafalgar Square, London, WC2N 5DN, UK
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4
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Hendriks L, Portmann C. Compound Specific Radiocarbon (
14
C) Dating of Our Colorful Past: from Theory to Practice. Helv Chim Acta 2022. [DOI: 10.1002/hlca.202200134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Laura Hendriks
- School of Engineering and Architecture, Institute of Chemical Technology HES-SO University of Applied Sciences and Arts Western Switzerland Pérolles 80 CH-1700 Fribourg Switzerland
| | - Cyril Portmann
- School of Engineering and Architecture, Institute of Chemical Technology HES-SO University of Applied Sciences and Arts Western Switzerland Pérolles 80 CH-1700 Fribourg Switzerland
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5
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Manoukian N, Whelton HL, Dunne J, Badalyan R, Smith AT, Simonyan H, Rothman MS, Bobokhyan A, Hovsepyan R, Avetisyan P, Evershed RP, Pollard AM. Diverse dietary practices across the Early Bronze Age 'Kura-Araxes culture' in the South Caucasus. PLoS One 2022; 17:e0278345. [PMID: 36542561 PMCID: PMC9770345 DOI: 10.1371/journal.pone.0278345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 10/31/2022] [Indexed: 12/24/2022] Open
Abstract
The Kura-Araxes (KA) cultural phenomenon (dated to the Early Bronze Age, c. 3500/3350-2500 BCE) is primarily characterised by the emergence of a homogeneous pottery style and a uniform 'material culture package' in settlements across the South Caucasus, as well as territories extending to the Ancient Near East and the Levant. It has been argued that KA societies practised pastoralism, despite a lack of direct examination of dietary and culinary practices in this region. Here, we report the first analyses of absorbed lipid residues from KA pottery to both determine the organic products produced and consumed and to reconstruct subsistence practices. Our results provide compelling evidence for a diversified diet across KA settlements in Armenia, comprising a mixed economy of meat and plant processing, aquatic fats and dairying. The preservation of diagnostic plant lipid biomarkers, notably long-chain fatty acids (C20 to C28) and n-alkanes (C23 to C33) has enabled the identification of the earliest processing of plants in pottery of the region. These findings suggest that KA settlements were agropastoral exploiting local resources. Results demonstrate the significance of applying biomolecular methods for examining dietary inferences in the South Caucasus region.
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Affiliation(s)
- Nyree Manoukian
- Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford, United Kingdom
- * E-mail:
| | - Helen L. Whelton
- Organic Geochemistry Unit, School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Julie Dunne
- Organic Geochemistry Unit, School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Ruben Badalyan
- Institute of Archaeology and Ethnography, National Academy of Sciences, Yerevan, Armenia
| | - Adam T. Smith
- Department of Anthropology, Cornell University, Ithaca, New York, United States of America
| | - Hakob Simonyan
- Scientific Research Center of the Historical and Cultural Heritage, Ministry of Culture, Yerevan, Armenia
| | - Mitchell S. Rothman
- Department of Anthropology, Widener University, Chester, Pennsylvania, United States of America
| | - Arsen Bobokhyan
- Institute of Archaeology and Ethnography, National Academy of Sciences, Yerevan, Armenia
| | - Roman Hovsepyan
- Institute of Archaeology and Ethnography, National Academy of Sciences, Yerevan, Armenia
| | - Pavel Avetisyan
- Institute of Archaeology and Ethnography, National Academy of Sciences, Yerevan, Armenia
| | - Richard P. Evershed
- Organic Geochemistry Unit, School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - A. Mark Pollard
- Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford, United Kingdom
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6
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Dating the emergence of dairying by the first farmers of Central Europe using 14C analysis of fatty acids preserved in pottery vessels. Proc Natl Acad Sci U S A 2022; 119:e2109325118. [PMID: 36252027 PMCID: PMC9618069 DOI: 10.1073/pnas.2109325118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Calendrical dating for the introduction of new food commodities affords enhanced understanding of major changes in human food procurement. Here, direct dating of milk residues from the Early Neolithic in Central Europe demonstrates the use of this unique secondary product from animals arrived with the earliest Linearbandkeramik settlers in the western (France, the Netherlands, and northwestern Germany) and eastern (Poland) extensions of the cultural group. At a time when most adult humans lacked the lactase-persistence gene variant, the adoption and intensification of a dairy-based economy would have had significant impact on human diet, evolution, and environment. Direct, accurate, and precise dating of archaeological pottery vessels is now achievable using a recently developed approach based on the radiocarbon dating of purified molecular components of food residues preserved in the walls of pottery vessels. The method targets fatty acids from animal fat residues, making it uniquely suited for directly dating the inception of new food commodities in prehistoric populations. Here, we report a large-scale application of the method by directly dating the introduction of dairying into Central Europe by the Linearbandkeramik (LBK) cultural group based on dairy fat residues. The radiocarbon dates (n = 27) from the 54th century BC from the western and eastern expansion of the LBK suggest dairy exploitation arrived with the first settlers in the respective regions and were not gradually adopted later. This is particularly significant, as contemporaneous LBK sites showed an uneven distribution of dairy exploitation. Significantly, our findings demonstrate the power of directly dating the introduction of new food commodities, hence removing taphonomic uncertainties when assessing this indirectly based on associated cultural materials or other remains.
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Li Z, Yuan F, Cao J, Hein A. Insights into the Residue Trapped in Glaze Cracks of Archaeological Ceramics Using Microchemical Analysis. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2022; 28:1-12. [PMID: 36065964 DOI: 10.1017/s1431927622012375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Searching for residue in the glaze of porcelain or stoneware is a difficult task because these glazes are high-fired, well vitrified, and nonporous. This paper analyzes the chemical composition of residue observed in glaze cracks of porcelain via SEM-EDS to determine how the crackle effect was produced, in particular, if it was intentionally created during production or the result of post-depositional processes. This study offers insights to a specific type of ancient Chinese porcelain called “Ge-type ware”, which has two different types of cracks, and whose origin has been debated for nearly 60 years because it has never been found at any kiln site. This paper analyzes the chemical composition of the two crack types, first using elemental mapping to ascertain the different mechanisms that produced these two crack types of the Heirloom Ge ware, and second using residue analysis and chemical fingerprinting to determine the provenance of this puzzling type of porcelain. In doing so, this paper demonstrates how the residue in the glaze of porcelain can be observed and analyzed via microchemical approaches and hopes to inspire more research using this technique in future.
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Affiliation(s)
- Zihan Li
- School of Archaeology, University of Oxford, Oxford, UK
| | - Feng Yuan
- Institute of Ancient Ceramic, Jingdezhen Ceramic Institute, Jingdezhen, China
| | - Jianwen Cao
- Art and Archaeology School, Jingdezhen Ceramic Institute, Jingdezhen, China
| | - Anke Hein
- School of Archaeology, University of Oxford, Oxford, UK
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8
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Casanova E, Knowles TDJ, Outram AK, Stear NA, Roffet-Salque M, Zaibert V, Logvin A, Shevnina I, Evershed RP. Direct 14C dating of equine products preserved in archaeological pottery vessels from Botai and Bestamak, Kazakhstan. ARCHAEOLOGICAL AND ANTHROPOLOGICAL SCIENCES 2022; 14:175. [PMID: 35996450 PMCID: PMC9388454 DOI: 10.1007/s12520-022-01630-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
UNLABELLED Direct and accurate radiocarbon dating of lipid residues preserved in ceramics is a recently established method that allows direct dating of specific food products and their inception in human subsistence strategies. The method targets individual fatty acids originating from animal fats such as ruminant dairy, ruminant adipose, non-ruminant adipose and aquatic fats. Horse lipid residues found in Central Asian pottery vessels are also directly dateable using this new method. Here we present the identification of equine lipid residues preserved in two pottery assemblages from the Neolithic and Eneolithic in Kazakhstan and their direct 14C dating. The site of Botai, previously radiocarbon-dated to the 4th millennium BC, was used as a reference to evaluate the dates obtained directly on horse lipids. The direct dating of equine products extracted from Botai potsherds are shown to be compatible with previous 14C dates at the site. The site of Bestamak, lacking previous14C measurements, had been relatively dated to the Neolithic based on pottery typologies. The direct dating of equine residues made it possible to anchor the pottery assemblage of Bestamak in the 6th millennium BC confirming their Neolithic attribution. These findings demonstrate the potential for dating horse products through a compound-specific approach, while highlighting challenges in 14C dating individual fatty acids from lipid extracts in which their abundances differ substantially. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s12520-022-01630-2.
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Affiliation(s)
- Emmanuelle Casanova
- Organic Geochemistry Unit, School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS81TS UK
- Present Address: UMR7209 Archaeozoology and Archaeobotany, Centre national de la recherche scientifique/Museum National d’Histoire Naturelle, CP56 55 rue Buffon, 75005 Paris, France
| | - Timothy D. J. Knowles
- Organic Geochemistry Unit, School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS81TS UK
- Bristol Radiocarbon Accelerator Mass Spectrometry Facility, University of Bristol, 43 Woodland Road, Bristol, BS81UU UK
| | - Alan K. Outram
- Department of Archaeology, University of Exeter, Laver Building, North Park Road, Exeter, EX4 4QE UK
| | - Natalie A. Stear
- Organic Geochemistry Unit, School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS81TS UK
| | - Mélanie Roffet-Salque
- Organic Geochemistry Unit, School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS81TS UK
| | - Viktor Zaibert
- Institute of Archaeology and Steppe Civilizations, Al-Farabi Kazakh National University, 71 Al-Farabi St, Almaty, Kazakhstan
| | - Andrey Logvin
- Archaeological Laboratory, Kostanay Regional University Named After A. Baitursynov, Baitursynov St., 47, Kostanay, Kazakhstan
| | - Irina Shevnina
- Archaeological Laboratory, Kostanay Regional University Named After A. Baitursynov, Baitursynov St., 47, Kostanay, Kazakhstan
| | - Richard P. Evershed
- Organic Geochemistry Unit, School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS81TS UK
- Bristol Radiocarbon Accelerator Mass Spectrometry Facility, University of Bristol, 43 Woodland Road, Bristol, BS81UU UK
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Interpreting ancient food practices: stable isotope and molecular analyses of visible and absorbed residues from a year-long cooking experiment. Sci Rep 2020; 10:13704. [PMID: 32855436 PMCID: PMC7452889 DOI: 10.1038/s41598-020-70109-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 07/21/2020] [Indexed: 12/26/2022] Open
Abstract
Chemical analyses of carbonized and absorbed organic residues from archaeological ceramic cooking vessels can provide a unique window into the culinary cultures of ancient people, resource use, and environmental effects by identifying ingredients used in ancient meals. However, it remains uncertain whether recovered organic residues represent only the final foodstuffs prepared or are the accumulation of various cooking events within the same vessel. To assess this, we cooked seven mixtures of C3 and C4 foodstuffs in unglazed pots once per week for one year, then changed recipes between pots for the final cooking events. We conducted bulk stable-isotope analysis and lipid residue analysis on the charred food macro-remains, carbonized thin layer organic patina residues and absorbed lipids over the course of the experiment. Our results indicate that: (1) the composition of charred macro-remains represent the final foodstuffs cooked within vessels, (2) thin-layer patina residues represent a mixture of previous cooking events with bias towards the final product(s) cooked in the pot, and (3) absorbed lipid residues are developed over a number of cooking events and are replaced slowly over time, with little evidence of the final recipe ingredients.
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Living off the land: Terrestrial-based diet and dairying in the farming communities of the Neolithic Balkans. PLoS One 2020; 15:e0237608. [PMID: 32817620 PMCID: PMC7444498 DOI: 10.1371/journal.pone.0237608] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/29/2020] [Indexed: 01/01/2023] Open
Abstract
The application of biomolecular techniques to archaeological materials from the Balkans is providing valuable new information on the prehistory of the region. This is especially relevant for the study of the neolithisation process in SE Europe, which gradually affected the rest of the continent. Here, to answer questions regarding diet and subsistence practices in early farming societies in the central Balkans, we combine organic residue analyses of archaeological pottery, taxonomic and isotopic study of domestic animal remains and biomolecular analyses of human dental calculus. The results from the analyses of the lipid residues from pottery suggest that milk was processed in ceramic vessels. Dairy products were shown to be part of the subsistence strategies of the earliest Neolithic communities in the region but were of varying importance in different areas of the Balkan. Conversely, milk proteins were not detected within the dental calculus. The molecular and isotopic identification of meat, dairy, plants and beeswax in the pottery lipids also provided insights into the diversity of diet in these early Neolithic communities, mainly based on terrestrial resources. We also present the first compound-specific radiocarbon dates for the region, obtained directly from absorbed organic residues extracted from pottery, identified as dairy lipids.
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Chemical evidence of dairying by hunter-gatherers in highland Lesotho in the late first millennium AD. Nat Hum Behav 2020; 4:791-799. [PMID: 32393839 DOI: 10.1038/s41562-020-0859-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 03/13/2020] [Indexed: 01/24/2023]
Abstract
The recovery of Early Iron Age artefacts and domestic animal remains from hunter-gatherer contexts at Likoaeng, Lesotho, has been argued to indicate contact between highland hunter-gatherers and Early Iron Age agropastoralist communities settled in lowland areas of southeastern Africa during the second half of the first millennium AD. However, disagreement between archaeozoological studies and ancient DNA means that the possibility that those hunter-gatherers kept livestock themselves remains controversial. Here we report analyses of pottery-absorbed organic residues from two hunter-gatherer sites and one agriculturalist site in highland Lesotho to reconstruct prehistoric subsistence practices. Our results demonstrate the exploitation of secondary products from domestic livestock by hunter-gatherers in Lesotho, directly dated to the seventh century AD at Likoaeng and the tenth century AD at the nearby site of Sehonghong. The data provide compelling evidence for the keeping of livestock by hunter-gatherer groups and their probable incorporation as ancillary resources into their subsistence strategies.
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