EAA 2015: Recycling session

k0DU5OibThe annual conference of the European Association of Archaeologists (EAA) will take place in Glasgow, UK in September 2015. Together with P. Bray, A. Cuénod, and C.N. Duckworth, I organise a session on ‘Recycling things and ideas: linking scientific, archaeological and conceptual approaches to the reuse of materials in the past’, which will certainly result in valuable new ideas, discussions and approaches.

Session abstract:

Recycling touches upon all aspects of archaeology, but it often suffers from its perceived ‘invisibility’ in the material record. Reuse, reforming and mixing of material alters its composition and shape, and can therefore directly affect conceptions of source, provenance, technology and chronology. The malleability and reuse of material challenges simple ideas of identity, value, economy and exchange. Despite the profound effects of recycling it is often difficult to identify and quantify in the archaeological record, particularly for materials and artefact-based studies (by comparison with, for example, architecture). This means that the manufacture of objects from ‘prime’ raw materials is often implicitly assumed to be standard practice. We are also in danger on relying on modern conceptions of recycling that focus on ecological concerns and coping with scarcity. Improved communication and co-operation across a range of disciplines offers new ways to better understand the flow of materials in the past. This session aims to provide a forum for these discussions and will highlight new approaches and models. Papers will examine how lab-based science, experimental archaeology, excavation and artefact-led archaeology, and conceptual archaeology can come together to identify and quantify recycling and its effects. This will be in conjunction with considering the challenges involved in pursuing inter-disciplinary work.

Further activities at the EAA will be the organisation of a round table about the Sellout of our past: different strategies of how to deal with illicit trafficking of European Cultural Heritage and a presentation on metal analyses of Bronze Age defensive armour.

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Getting ready to start

Before work can begin on the arsenic bronze, all relevant safety aspects must be considered, i.e. I must ensure that the work will not harm myself or others in the lab. Reading the standard precautions for arsenic (e.g. from Sigma Aldrich) was informative if not a little scary.

Full respiratory equipment (e.g. full face particle respirator type N100 with appropriate cartridges and filters), a disposable complete suit protecting against dust and particles, and gloves will be worn as a precaution to ensure personal safety in the event of a toxic arsenic oxide vapor release during the experimental work.

The experiments will be performed under an extractor hood equipped with adequate filters in case any leakage occurs. The reactor consists of a crucible or a quartz vial sealed with a consumable glass / quartz pipe. The pipe is shaped to cool the vapours from the reactor and direct them into a container (e.g. a beaker) where a basic water solution will receive and fix the As-rich compounds in a stable arsenate salt. The glassware and the arsenate-rich solution will be stored as hazardous waste in secure gas and watertight containers and disposed of correctly by a licensed company, together with the laboratory gloves, coats and filters.

 

References

Read more about the physiologic effects of arsenic exposure here.

How it all began

The core idea of this project has been in development for a very long time – by now, it must be over 10 years. While writing my PhD about European Bronze Age swords I came across the article of McKerrell – Tylecote 1972 and became curious about the amount of arsenic that actually remains in bronze after several (prehistoric) recycling processes. I tried to find further literature focusing on this but apart from the article of Lechtman 1996, the unpublished PhD-thesis and some hard-to-get articles of Paul Budd, as well as the article of Northover 1989, not much seemed to have been done until around 2005.

In the meantime I focused on other topics: I finished my PhD, documented Bronze Age weapons and tools in the Baltic States, then moved to Carinthia and started to work at the local Landesmuseum. Amongst other things, research projects of the Austrian FWF, CHARISMA and Marie Skłodowska-Curie actions subsequently permitted me to study and analyse e. g. European Bronze Age body armour at the Laboratorio di Metallurgia e Materiali in Genoa.

However, I remained intrigued by the loss of arsenic during prehistoric smelting and melting. Every time I saw diagrams in archaeological publications linking the amounts of As, Sb, Ni and Ag together in order to locate geographically a copper mine, I had the Ellingham diagram of the formation of common metal oxides in mind, noting that arsenic (as well as Sb) is far from being as stable as these publications sometimes would lead one to believe.

A literature study at the end of 2014 indicated that even up until that point, no further experiments had been published. However, recent studies carried out by M. Pollard, P. Bray and A. Cuenod demonstrate the importance of arsenic as a marker for the intensity and / or number of recycling activities in the Bronze Age, and how it may indicate direct or indirect connections between the owner of the final object and the mine(s) where the copper was originally produced. In addition, thermodynamic studies on CuAs are now close to being published (B. Sabatini).

Starting with a project to investigate the construction of out-of-equilibrium phase diagrams of Cu-As, to evaluate mechanical properties and characteristics of arsenical bronzes and finally, to quantify and evaluate the loss of arsenic as it occurred during prehistoric manufacturing processes, will certainly be a challenge – scientifically as well as for health reasons, since arsenic is not really famous for its positive effects on one’s health.

Ultimately though, I am thrilled that from July 2015 on I can finally start to work with arsenical bronze after all these years – and especially to have the opportunity to carry out this project at the IRAMAT-CRP2A at Bordeaux in cooperation with the LMM at Genova!

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Project presentation at the University of Leicester, UK

In April 2015, prior to the project’s official start, I was already able to present my ArsenicLoss project ideas and work plan at the ‘Glass and Metal Recycling in Archaeology and Archaeometry’ workshop at the University of Leicester, UK. The workshop was kindly organised by A. Cuénod and C.N. Duckworth (a warm thank you to both for everything!) in the frame of the ERC-funded Trans-Sahara project. This workshop and the associated discussion possibilities provided valuable hints for the experimental set-up and laid the groundwork for cooperation with other colleagues.