Potential of lead elemental and isotopic signatures for authenticity and geographical origin of Bordeaux wines.

Lead concentrations and lead isotope ratios of 43 authentic Bordeaux wines from prestigious châteaux and 14 suspicious Bordeaux origin were determined to evaluate their potential for authenticity and geographical origin assessment. Results have shown that the total Pb concentrations in Bordeaux wines drastically decreased over the previous 50 years with a clear shift of isotopic signatures towards geogenic values corresponding to an overall trend of European environmental lead monitoring. The Pb isotopic ratios determined in both series of samples clearly demonstrated that suspicious Bordeaux wines displayed Pb isotopic signatures statistically distinctive from those obtained for authentic wines. This observation was confirmed by the three-isotope mixing lines obtained between the geogenic and the anthropogenic Pb isotopes data that characterize European and Asian sources. The use these specific three-isotope plots allows a non-ambiguous discrimination between authentic Pauillac AOC and the counterfeited ones.