Lead isotopic evidence for a mixed provenance for Roman water pipes from Pompeii

Lead isotope analysis has been applied to the investigation of some Roman objects found in the town of Pompeii, consisting mostly of fistulae from the Augustan water supply system. The results of the analyses have produced ratios between 18.10 and 15.72 for 207Pb /204Pb and between 38.21 and 38.98 for 208Pb/204Pb. These data point to a fairly complex origin for the lead artefacts, probably involving several successive meltings and recyclings of a rather heterogeneous lead supply. The spread of lead isotope ratios can only be reconciled with a multiplicity of end-members, at least three, but very probably more. There is one certain Sardinian ore, other indistinguishable Hercynian ores of Sardinia and/or Spain, and several different Alpine Mesozoic-Tertiary mineralizations of the Mediterranean basin (Spain, Greece, Tuscany).