Using the historical atmospheric lead-deposition record as a chronologicalmarker in sediment deposits in Europe

Atmospheric deposition of large-scale lead pollution has occurred for at le ast 3000 years in Europe. Metal production and smelting were the main sourc es until the twentieth century when emissions from vehicles using alkyl-lea ded petrol became dominant. Analyses of lake-sediment and peat deposits in Sweden and other regions in Europe, as well as ice cores from Greenland, su ggest synchronous temporal changes in past pollution deposition. Characteri stic features in the atmospheric pollution fallout were caused by: the peak in lead production during the Roman period; the marked Mediaeval increase in mining and metal production; the rapidly increasing use of cars and lead ed gasoline after the second world war along with increased industrial emis sions until around 1970, which was followed by a major improvement due to e nvironmental legislation. For northern Europe at least, these characteristi c changes can be used to determine, with reasonable accuracy, at which leve ls AD 0, AD 1000-1200 and AD 1970 are situated in lake-sediment deposits. T o identify these levels, stable lead isotope analyses (Pb-206/Pb-207 ratios ) have proven to be very useful besides concentration determinations. Parti cularly useful are the isotope analyses in areas, such as Sweden, where the differences in Pb-206/Pb-207 ratios are large between the natural catchmen t lead and the pollution lead.