The sulphur threat to marine archaeological artefacts : acid and iron removal from the Vasa
An outbreak of acidity and sulphate salts was observed on the hull of the 17th-century Swedish warship Vasa, following humidity variations in the Vasa Museum during the rainy summer in 2000. Analyses of total sulphur in oak cores sampled from 16 locations showed, in the outermost 2 cm., mean concentrations betwen 0.2 and 6 mass percent. Synchrotron-based sulphur K-edge X-ray absorption spectroscop