Ti and Pb Concentrations in Rainwater-Fed Bogs in Europe as Indicators of Past Anthropogenic Activities

Abstract

Chemical and physical analyses of dated ombrotrophic peat cores from 8 European regions were undertaken to determine the effect of forest clearances, farming, mining and smelting on the composition of atmospheric aerosols. Elemental concentrations in peat were determined using XRF and the mean concentrations of Ti and Pb in peat as well as Pb enrichment factors (Pb EFs) were calculated for each region and for different time periods (Roman Times, Dark Ages, Middle Ages, modern times). The results show that the concentration of Ti, Pb and the calculated Pb EFs closely follow changes in land use history extending back thousands of years. Concentrations of Ti, for example, reflect changing soil dust inputs in response to forest clearing and agriculture. Lead emissions are characterized by considerable continental-scale variations: elevated concentrations and EFs during the Roman Period at most sites, very high concentrations and EFs in the Harz Mountains during the Medieval period, and elevated to high concentrations and EFs during modern times at all sites. The findings indicate that peat cores from ombrotrophic bogs are useful not only for quantifying temporal changes in metal emissions, but also for identifying spatial variations on scales ranging from regional to global.