Ta1_02

Why the radiolabelling approach is the gold standard for ecotoxicological investigation of nanoplastics?

AL SID CHEIKH M¹, De Maria D², Kaegi R³, Wacker L²

¹University Of Surrey, Guildford, United Kingdom, ²Swiss Federal Institute of Technology (ETH), Laboratory of Ion Beam Physics (LIP), Zurich, Switzerland, ³Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Dubendorf, Switzerland

Studies investigating the effects of nanoplastics (NPs) on aquatic organisms used concentrations 2 to 7 order-of-magnitudes higher than those predicted in the open ocean to detect NPs. These studies divided the community into those who sounded the alarm based on observed ecotoxicological effects, and those who predicted that concentrations of NPs in the environment were well below any threshold-effect. In reality, most experiments were inadequately designed, and the results were therefore unsatisfactory. Fit-to-purpose experimental designs have been hindered by a lack of appropriate NP models, tracking methods, and monitoring strategies for environmentally realistic concentrations.

Using ¹⁴C-labelled NPs and conventional nuclear techniques, I recently modelled that scallops chronically exposed (over a year) to environmentally realistic NP concentrations (15 µg/L) could accumulate NPs and reach concentrations in body tissues at which effects were observed by those who raised sounded the alarm. Surprisingly, this suggests that NPs in organisms have already exceeded threshold levels and could be damaging the marine biota.

Here, I present an innovative approach to overcome the analytical limitations for the detection and quantification of NPs under realistic environmental conditions. By combining ¹⁴C-labelling of NPs with the ultimate sensitivity of Accelerator Mass Spectrometry (AMS), we will be able to conduct exposure experiments under realistic conditions. The ¹⁴C-labelling coupled with the AMS will provide an unprecedented level of sensitivity, allowing us for the first time, to account for any ¹⁴C when performing long-term experiments, closing the gap on many critical environmental questions about plastics.

Ta1_03

Application of ¹⁴C dating in the routine forensic practice: outcome of the IAEA Coordinated Research Project

Calcagnile L¹, Hajdas I², Molnar M³, Varga T^3,4,5, Major I³, D'Elia M¹, Jull A^3,6, Simon A⁷, Quarta G¹

¹CEDAD-Centre of Applied Physics, Dating and Diagnostics, University Of Salento, Lecce, Italy, ²Laboratory for Ion Beam Physics, ETHZ, Zürich, Switzerland, ³International Radiocarbon AMS Competence and Training (INTERACT) Center, Institute for Nuclear Research, Debrecen, Hungary, ⁴University of Debrecen, Doctoral School of Physics, Debrecen, Hungary, ⁵Isotoptech Ltd, Debrecen, Hungary, ⁶Dept. of Geosciences, University of Arizona, Tucson, USA, ⁷Division of Physical and Chemical Sciences, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Wien, Austria

Since 2017 the IAEA (International Atomic Energy Agency) has undertaken a Coordinated Research Project (CRP F11021) entitled “Enhancing Nuclear Analytical Techniques to meet the Needs of Forensics Sciences”. The scope of the program is to develop and utilize the capabilities of nuclear and accelerator-based analytical techniques towards recognized needs of forensic sciences that could not be efficiently addressed by other methods. Indeed, despite the relevant advantages of accelerator-based techniques, their application in the routine forensics practice appears to be still limited. Aim of the CRP was to support long term collaborations and networking between experts in nuclear analytical techniques and forensic science stakeholders such as law enforcement agencies, police corps and international organizations. We report on the outcomes of one of the WPs (WP4) which was entirely dedicated to the applications of ¹⁴C. Within this WP, in order to cope with the factors limiting the impact of AMS dating in forensics, a detailed research program was defined on the basis of discussions with forensic stakeholders and experts of other analytical techniques. The need to define common guidelines and quality assurance protocols for the application of ¹⁴C was established, also considering possible ethical issues, interpretation of data and the assessment of the achievable chronological resolution on classes of samples relevant in forensics. Different intercomparison exercises were then organized and run among three AMS facilities: CEDAD (Italy), ETHZ (Switzerland) and Isotoptech-ATOMKI (Hungary) aimed at addressing these issues on different sample materials such as ivory, bones, paper, textiles and foodstuff (wine and coffees).

Ta1_04

The role of ¹⁴C dating in the identification of Missing Persons in Cyprus

Quarta G¹, Eleftheriou T², Engin I², Maruccio L¹, D'Elia M¹, Calcagnile L¹

¹CEDAD-University Of Salento, Lecce, Italy, ²Committee on Missing Persons in Cyprus, Cyprus, Cyprus

The Committee on Missing Persons in Cyprus (CMP) is a bicommunal committee with the mandate to locate and identify the skeletal remains of 2002 missing persons from the inter-communal fighting of 1963-1964, as well as the events of July 1974.

During the periods of conflict, several archaeological sites and old cemeteries were used as primary burial sites, as they were easily accessed by the persons involved in the interment and little effort was needed to conceal the bodies. The relatively large post-mortem interval and the generally poor post-mortem preservation of the skeletal remains poses an additional challenge in the forensic examination process, particularly in the absence of a context or artefacts/evidence.

Between 2016 to 2020, the CMP has been collaborating with CEDAD-Centre of Applied Physics, Dating and Diagnostics at the University of Salento to clarify the relevancy of several cases by using radiocarbon dating. The CMP submitted 139 unresolved cases to CEDAD, out of which 112 cases were determined to be archaeological in date and irrelevant to the CMP project. For the remaining samples bomb ¹⁴C was detected in bone collagen and the bomb peak dating technique was then used or further investigation of the cases.

The obtained results show that ¹⁴C dating on human remains recovered in archaeological sites and old cemeteries is an effective method to determine the year of death of the remains and then to identify the forensic significance of the cases recovered by the CMP.

Ta1_05

Radiocarbon analysis of human remains in forensic cases

Cherkinsky A¹, Bengtson J², Prasad G¹

¹University Of Georgia, Athens, United States, ²Southeast Missouri State University, Cape Girardeau, United States

Estimation of the date of birth and death of deceased individuals, whose remains make identification impossible, represents an important task for forensic science. The dramatic spike of ¹⁴C concentration in atmosphere in 1955 - 1963 due to above ground nuclear testing and its subsequent decline is documented by high resolution records which could help to solve this problem. We analyzed the proportion of bomb radiocarbon in the bioapatite of enamel and collagen of dentine to solve these problems. We analyzed seven cases of remains of unidentified victims recovered by law enforcement and submitted to Southeast Missouri State University for anthropological analyses. Some of them were recovered decades ago, while some were recovered more recently. All remains were analyzed on collagen fraction of the dentine and bioapatite fraction of the enamel. In two of sevens cases collagen was formed before 1950 AD collagen and these cases were excluded from determination. In the third case, enamel was formed before 1950 AD but death occurred after the bomb spike in 1962-1964 AD according of ¹⁴C concentration in collagen and the age of the victim. The other four cases were fitted in the bomb curve and allowed quite precise determination of dates of birth and death.

The δ¹³C and δ¹⁵N values for dentine collagen were higher than it would be expected for pure terrestrial diet, implying some consumption of marine food that could lead to reduced ¹⁴C concentration. Taking into account the potential marine reservoir effect could slightly reduce the ages of those persons.

Ta1_06

MODELLING CORRECTIONS OF BOMB-PULSE RADIOCARBON DATING IN FORENSIC CASES

Sveinbjörnsdóttir A¹, Olsen J², Heinemeier J²

¹Institute of Earth Sciences, University of Iceland, Reykjavík, Iceland, ²Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark

Identification of human remains by radiocarbon dating and stable isotope approach can be of extreme importance in forensic cases. However, radiocarbon dating has to rely on modelled corrections due to radiocarbon changes in the atmosphere, collagen turnover rate and marine reservoir effect that are often difficult to estimate and verify. In this presentation, we will ascertain how close the modelled corrections are to reality by comparing radiocarbon ages of human individuals with the known actual time of death (and birth).

Two bone samples from unidentified individuals were radiocarbon dated by request of the Icelandic police, to determine whether the human remains were recent and of forensic relevance. In both cases the bones were well preserved and the extracted collagen of good quality. The dates were performed in 2017 and 2019 respectively, and both individuals turned out to be modern, falling within the bomb-pulse period. Isotope data showed no or limited indication of marine diet. To provide a quick forensic result, we took the naïve approach of a standard ten-year correction for bone collagen turnover and no marine correction.

After our report, the police applied DNA testing and managed to identify both individuals. Accordingly, we now know their time of birth as well as their death dates. In both cases, we had estimated their time of death too early by 10 and 20 years respectively. We have initiated attempts of better modelling of bone turnover and marine reservoir corrections in connection with bomb-pulse dating.

Ta1_07

The Scale of the Trade: Determining a Pangolin’s Date-of-Death Using F¹⁴C

Barr E¹, Wood R^1,2, Meagher P³, Fallon S¹

¹The Australian National University, Canberra, Australia, ²University of Oxford, Oxford, England, ³Taronga Conservation Society, Sydney, Australia

In wildlife forensics, it is important to know when an animal was killed to aid in the prosecution of traders and to gain a deeper understanding of the mechanisms of the trade. Such is the case for the pangolin (Manidae), a scaly mammal considered to be the most highly trafficked animal in the world. Pangolins are often poached for their hard, cornified scales that are used commonly in traditional medicines. Our study attempts to analyse F¹⁴C of keratin across a scale using accelerator mass spectrometry to determine an animal’s date of death. We have developed an improved understanding of how the scale grows and propose the most effective method for producing a chronology is to take a series of samples proximal-distally down the scale. This assumes the proximal apex of the scale is the oldest tissue and that the distal attachment point to the epidermis is the most recent tissue and will provide the closest value to a date of death. We investigate whether results could be skewed by a reservoir effect created by the termites in a pangolin’s diet, if the termites are feeding on old-carbon within decaying wood. By developing an effective method to determine the date of death of an animal from their scales alone, we may be able to better prosecute illegal traders and interrupt the current momentum driving pangolins towards extinction.

Ta1_08

Taste it or date it: authentication of 10-yr and 20-yr fortified wines

Palstra S¹, Meijer H¹

¹University of Groningen, Groningen, Netherlands

Consumers of several fortified wines tend to believe that these wines have matured

on casks for a specific period of time, e.g. 10, 20 of 30 years, because this is stated

on the labels of the bottles. These statements give the idea of additional value and

quality of the product to the consumer. EU-regulations request that claims about the

content of food and beverages on product labels are correct and not misleading.

In the production of fortified wines it is common practice to blend wines with

different maturation ages to obtain wines that fulfil the defined and verified

requirements regarding taste, smell, looks and several other aspects of matured

fortified wines with a certain age. The real (average) maturation age is however not

verified.

For one of our customers we have verified the (average) maturation ages for a set of

20 different fortified wines by measuring radiocarbon in the ethanol and sugar

fractions of these wines. In this presentation we will show the applied method and

its verification. We will discuss the results, which indicate that part of the

investigated fortified wines might have younger maturation ages than stated on the

bottle.

Ta1_09

Sweet bomb-peak in the historical Tokaji Aszú wines

Molnar M¹, László E¹, Molnár A^1,2,3, Varga T^1,2,3

¹INTERACT AMS Laboratory, Debrecen, Hungary, ²University of Debrecen, Doctoral School of Physics, Debrecen, Hungary, ³Isotoptech Zrt., Debrecen, Hungary

Tokaji Aszú is one of the most important and traditional wines in the world, produced since the XVI. Century. It is a special wine produced in the Tokaj wine region (Hungary); it is the nectar of individually hand-picked “aszú”berries botrytised on the wine stock. It is made by bathing the dough in high quality must or wine of the same year from the Tokaj wine region. Following fermentation, it is maturing and refining in oak casks placed in a constant-temperature cellar. Besides the unique quality, this also explains the high price of Tokaji Aszu wines, as it is an extremely labour-intensive process. Thanks to its high sugar and acid content it is already highly enjoyable at the age of 150 years, which is why Tokaji Aszu is very popular among wine collectors. In this study we have investigated sets of several decades collection of Tokaji Aszu wine from different wine yards. Aszú samples were analyzed by AMS ¹⁴C technique to prove the power of high resolution dating/age determination by AMS technique on prestigious old wines. Atmopsheric ¹⁴C bomb-peak (1963-2020) allows one-year resolution wine „dating”. Besides the wine ¹⁴C analyses, we have investigated their ³H signal too, to have an independent proxy regarding the bomb-signal. On the other hand, we compared the Aszú-bomb-curve to the local (Hungarian) atmospheric ¹⁴C records from tree rings and direct air sample observations.

Ta1_P01

Radiocarbon dating of forensic human bone to estimate the postmortem interval (PMI)

Indra L¹, Hamann C², Szidat S³, Kanz F⁴, Lösch S¹, Lehn C⁵

¹Department of Physical Anthropology, Institute of Forensic Medicine, University of Bern, Bern, Switzerland, ²Leibniz-Laboratory for Radiometric Dating and Stable Isotope Research, Christian-Albrechts-Universität zu Kiel, Kiel, Germany, ³Department of Chemistry, Biochemistry and Pharmaceutical Sciences & Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland, ⁴Center for Forensic Medicine, Medical University of Vienna, Vienna, Austria, ⁵Institute of Legal Medicine, Ludwig-Maximilians-University of Munich, Munich, Germany

Estimating the postmortem interval (PMI) of human remains is important in forensic anthropology, e.g. to aid the identification process. For this, a frequently employed method is radiocarbon dating, using the bomb-peak-model after 1950. Because of the bone remodeling, there is a lag time between the calibrated skeletal radiocarbon data and the actual year of death of an individual. The remodeling rate depends on the physiological state of the bone and may be different for each skeletal element. Quantifying these factors is challenging. By adding more data to this research field, our study aims to enhance the accuracy of radiocarbon-based PMI estimations of skeletal remains.

We radiocarbon-dated bone collagen from 25 forensic cases in Switzerland, Germany and Austria, of individuals that had died between 19 and 98 years of age. We sampled skull (occipital, parietal and temporal bone) and femur and combined the calibrated F¹⁴C values with the known individual data of the deceased to calculate collagen remodeling rates.

Our results show that petrous bone remodeling rates are low and lag times increasing roughly proportionate with age-at-death. The petrous bone is therefore less suitable for PMI estimation because its radiocarbon value refers to the period of the (early) childhood. Femur and skull remodeling rates are comparable. However, the inter-individual variability is pronounced, especially in the elderly. To create a universal model for year-of-death estimation based on the radiocarbon data, we need to better understand factors such as physiological status of the individual and its influence on skeletal turnover rates.

Ta1_P02

Chronological records in animal tissues

Pachnerova Brabcova K¹, Kufnerova J¹, Valasek V¹, John D^1,2, Petrova M¹, Brychova V¹, Svetlik I¹

¹Nuclear Physics Institute of the CAS, Praha, Czech Republic, ²Czech Technical University in Prague, Praha, Czech Republic

Radiocarbon dating of recent and near-future samples faces an inability to distinguish these from the pre-bomb peak ones. It is caused by radiocarbon levels decline to pre-bomb activities.

If the samples in question are of the animal tissues, such as protected species being dated for legal purposes, possible mitigation of this unfavourable trend lies in exploitation of the tissue chronological record. In the best case, the known chronology can anchor the sequence on radiocarbon calibration curve, and thus reduce the ambiguity of the dating results.

Our research aims on tissues of several endangered species, such as ivory of elephants (Loxodonta africana), scales of pangolins (Smutsia gigantea, Manis tricuspis), or tortoise shells (Testuda hermanni, Testudo graeca, Testudo marginata). Radiocarbon dating of incremental lines was accompanied with other analysis, optical and scanning electron microscopy and X-ray fluorescence.

Ta1_P03

Absorption and Distribution of Ultra-Trace Exogenous ¹⁴C Urea in Rats

Wang L, Tang J^1,2, Zhang G¹, Shi S¹, Chen D¹, Qi L¹, Yang P³, Zhang X³, Xia C³, Shen H^1,2

¹Guangxi Normal University, Guilin, China, ²Guangxi key laboratory of nuclear physics and nuclear technology, Guilin, China, ³Guilin Medical University, Guilin, China

A study on absorption and distribution of radiocarbon labeled urea in rats was carried out at the ultra-trace level with AMS. The drug concentrations in plasma and tissues of rats after an oral administration of an ultra-trace dose of [¹⁴C]urea were measured. The drug concentration vs time curves in plasma and tissues were obtained. The results show that the drug distribution of ultra-trace dose is different from that of conventional-dose, and the [¹⁴C]urea is excreted mainly through urine and respiratory. This study provides information on the pharmacokinetics and tissue distribution of exogenous urea in rats at the ultra-trace level and verifies the feasibility of using AMS for ultra-trace dose drug research beyond the traditional measurement range.

Keywords: AMS, ultra-trace dose, [¹⁴C]urea, pharmacokinetics, distribution

Ta1_P04

Bomb pulse dating of human calculi

Wang ^1,2,3, Ding P^1,2,3, Shen C^1,2, Zhu S^2,4

¹State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, , Guangzhou, China, ²CAS Center for Excellence in Deep Earth Science, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzho, China, ³Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou), Guangzhou, China, ⁴State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China

The onset ages of various human calculus diseases are usually later than the emergence ages of calculi in the body because the patients seek medical attention after the symptoms and complications are perceptible. Knowing the emergence ages of calculi will help doctors figure out the causes and benefit public health. In this study, we collected three kinds of calculi, including sialoliths (S), gallstone (GS), and bladder stones (BS) from 8 donors in Guizhou, Southwest China. Five of these samples are big and have multiple layers. We separated them into the inner core and outer crust parts and studied their ¹⁴C ages and ¹³C signatures. The results show the bomb pulse dating ages of BS and GS (c. 0 - 6 yrs) are much younger than those of sialoliths (c. 9 - 44 yrs). The difference between the ages of the outer crusts and inner cores indicates the growth period of calculi, ranging from 0.4 to 6.9 yrs. The growth rates of GS and BS are between 2.8 to 4.1 mm/yr. The δ¹³C values of sialoliths, GS, and BS range from -23.9 to -21.5 ‰, -22.6 to -22.2 ‰, and -20.5 to -19.5 ‰, respectively. Distinguish ages and stable isotope distribution patterns likely exist among different kinds of calculi, but further studies are needed to give a statistical conclusion.