Deterioration of the seventeenth-century warship Vasa by internal formation of sulphuric acid


The seventeenth-century Swedish warship, Vasa, was recovered in good condition after 333 years in the cold brackish water of Stockholm harbour. After extensive treatment to stabilize and dry the ship's timbers1, the ship has been on display in the Vasa Museum since 1990. However, high acidity and a rapid spread of sulphate salts were recently observed on many wooden surfaces2, which threaten the continued preservation of the Vasa. Here we show that, in addition to concentrations of sulphate mostly on the surface of oak beams, elemental sulphur has accumulated within the beams (0.2–4 per cent by mass), and also sulphur compounds of intermediate oxidation states exist. The overall quantity of elemental sulphur could produce up to 5,000 kg of sulphuric acid when fully oxidized. We suggest that the oxidation of the reduced sulphur—which probably originated from the penetration of hydrogen sulphide into the timbers as they were exposed to the anoxic water—is being catalysed by iron species released from the completely corroded original iron bolts, as well as from those inserted after salvage. Treatments to arrest acid wood hydrolysis of the Vasa and other wooden marine-archaeological artefacts should therefore focus on the removal of sulphur and iron compounds.

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Figure 1: Outline of the hull of the Vasa with sample positions indicated.
Figure 2: Sulphur K-edge XANES spectra from core C1a (oak from upper gun deck of the Vasa).
Figure 3: XPS spectra of oak-wood cores C1b and C2 from the Vasa.
Figure 4: Depth profiles of total sulphur and iron in cores for oak beams of the Vasa.
Figure 5: Redox (Pourbaix) diagram EH = f(pH) showing predominant sulphur-containing species in equilibrium with iron and sodium ions in aqueous solution (calculated for [Fe3+] = 0.05 M, [Na+] = 0.4 M, [SO2-4] = 0.35 M).


  1. 1

    Håfors, B. Conservation of the Swedish Warship Vasa from 1628 1–180 (Vasa Museum, Stockholm, Sweden, 2001).

    Google Scholar 

  2. 2

    Sandström, M., Jalilehvand, F., Persson, I., Gelius, U. & Frank, P. in Proc. 8th ICOM-CC WOAM Conference (ed. Hoffmann, P.) (ICOM, Committee for Conservation, Working Group on Wet Organic Archaeological Materials, Stockholm, in the press).

  3. 3

    Peterson, C. E. in Archaeological Wood, Properties, Chemistry and Preservation (eds Rowell, R. M. & Barbour, R. J.) 433–449 (Advances in Chemistry Series 225, American Chemical Society, Washington DC, 1990).

    Google Scholar 

  4. 4

    Blanchette, R. A., Nilsson, T., Daniel, G. & Abad, A. in Archaeological Wood, Properties, Chemistry and Preservation (eds Rowell, R. M. & Barbour, R. J.) 141–192 (Advances in Chemistry Series 225, American Chemical Society, Washington DC, 1990).

    Google Scholar 

  5. 5

    Barkman, L. in National Bureau of Standards (Spec. Publ. No. 479) 155–166 (Gaithersburg, Maryland, 1977).

    Google Scholar 

  6. 6

    Stumm, W. & Morgan, J. J. in Aquatic Chemistry, Chemical Equilibria and Rates in Natural Waters 3rd edn, 464–498 (Wiley-Interscience, New York, 1996).

    Google Scholar 

  7. 7

    Jespersen, K. in Proc. ICOM Working Groups on Wet Organic Archaeological Materials and Metals (ed. MacLeod, I. D.) 141–152 (Western Australian Museum, Fremantle, 1989).

    Google Scholar 

  8. 8

    Baird, C. in Environmental Chemistry 2nd edn, 427–437 (Freeman, New York, 1999).

    Google Scholar 

  9. 9

    Lowson, R. T. Aqueous oxidation of pyrite by molecular oxygen. Chem. Rev. 82, 461–497 (1982).

    CAS  Article  Google Scholar 

  10. 10

    Emery, J. A. & Schroder, H. A. Iron catalysed oxidation of wood carbohydrates. Wood Sci. Technol. 8, 123–137 (1974).

    CAS  Article  Google Scholar 

  11. 11

    Kilminster, K. Preserving our Past. An Investigation into Archaeological Wood from the Shipwreck of the Batavia. BSc thesis, Univ. Western Australia (2001).

    Google Scholar 

  12. 12

    Bernson, A. Metal Ion Coordination in Polymer Electrolytes. PhD thesis (Acta Univ. Ups. Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 182, Institute of Chemistry, Uppsala Univ. 1–34 (1996).

    Google Scholar 

  13. 13

    Gray, F. M. in Polymer Electrolytes (ed. Connor, J. A.) 1–136 (RSC Materials Monographs, The Royal Society of Chemistry, Cambridge, 1997).

    Google Scholar 

  14. 14

    Guilminot, E., Dalard, F. & Degigny, C. Electrochemical study of iron corrosion in various concentrations of polyethylene glycol (PEG 400) solutions. Eur. Fed. Corros. Publ. 28, 300–309 (2000).

    CAS  Google Scholar 

  15. 15

    Ahrland, S., Dahlgren, Å & Persson, I. Stabilities and hydrolysis of some iron(III) and manganese(III) complexes with chelating ligands. Acta Agric. Scand. 40, 101–111 (1990).

    CAS  Article  Google Scholar 

  16. 16

    Fengel, D. & Wegener, G. in Wood, Chemistry, Ultrastructure, Reactions (Walter de Gruyter, Berlin, 1989).

    Google Scholar 

  17. 17

    Jalilehvand, F. in Structure of Hydrated Ions and Cyano Complexes by X-Ray Absorption Spectroscopy 1–80 (PhD thesis, Department of Chemistry, Royal Institute of Technology, Stockholm, 2000); available at 〈〉.

    Google Scholar 

  18. 18

    Hedman, B. et al. Sulfur K-edge X-ray absorption studies using the 54-pole wiggler at SSRL in undulator mode. Nucl. Instr. Methods A 246, 797–800 (1986).

    ADS  Article  Google Scholar 

  19. 19

    Frank, P. et al. A large reservoir of sulfate and sulfonate resides within plasma cells from the tunicate Ascidia ceratodes, revealed by X-ray absorption near-edge structure spectroscopy. Biochemistry 26, 4975–4979 (1987).

    CAS  Article  Google Scholar 

  20. 20

    Pickering, I. J. et al. Analysis of sulfur biochemistry of sulfur bacteria using X-ray absorption spectroscopy. Biochemistry 40, 8138–8145 (2001).

    CAS  Article  Google Scholar 

  21. 21

    Smith, T. A., DeWitt, J. G., Hedman, B. & Hodgson, K. O. Sulfur and chlorine K-edge X-ray absorption spectroscopic studies of photographic materials. J. Am. Chem. Soc. 116, 3836–3847 (1994).

    CAS  Article  Google Scholar 

  22. 22

    Frank, P., Hedman, B. & Hodgson, K. O. Sulfur allocation and vanadium-sulfate interactions in whole blood cells from the tunicate Ascidia ceratodes, investigated using X-ray absorption spectroscopy. Inorg. Chem. 38, 260–270 (1999).

    CAS  Article  Google Scholar 

  23. 23

    George, G. N. & Gorbaty, M. L. Sulfur K-edge X-ray absorption-spectroscopy of petroleum asphaltenes and models. J. Am. Chem. Soc. 111, 3182–3186 (1989).

    CAS  Article  Google Scholar 

  24. 24

    Gelius, U. et al. A new ESCA instrument with improved surface sensitivity, fast imaging properties and excellent energy resolution. J. Electron Spectrosc. Relat. Phenom. 52, 747–785 (1990).

    CAS  Article  Google Scholar 

  25. 25

    Puigdomenech, I. MEDUSA and HYDRA; available at 〈〉 (2001).

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We thank B. Hedman and K. O. Hodgson for support and facilities at SSRL, L. Göthe for technical assistance, and B. Lundvall at the Vasa Museum for core sampling and information. This work is supported by grants from the Knut and Alice Wallenberg Foundation, Sweden, and the Department of Energy, Office of Environmental Research (DOE-BER). SSRL is operated by the Department of Energy, Office of Basic Energy Sciences, USA.

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Correspondence to Magnus Sandström.

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Sandström, M., Jalilehvand, F., Persson, I. et al. Deterioration of the seventeenth-century warship Vasa by internal formation of sulphuric acid. Nature 415, 893–897 (2002).

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