A new approach for quantifying cumulative, anthropogenic, atmospheric leaddeposition using peal cores from bogs: Pb in eight Swiss peat bog profiles

Feat cores taken from eight Swiss peatlands were used to calculate inventor ies of anthropogenic Ph using either Sc or Zr to quantify Pb derived from r ock weathering. The shapes of the Pb/Sc and Pb/Zr profiles suggest that Pb was supplied exclusively by atmospheric deposition at an sites. At one of t he sites (Etang de la Gruere), anthropogenic Pb was calculated using both S c and Zr as the conservative reference element. Lithogenic Pb determined us ing Sc was twice that obtained using Zr, possibly because Zr resides only i n zircons which are dense compared to pyroxene and amphibole which are the main Sc-bearing phases in the earth's crust. However, the inventory of 'nat ural' Pb (supplied almost entirely by soil dust) is dwarfed by the anthropo genic inventory such that anthropogenic Pb calculated using Sc and Zr agree to within 5%. The total amount of anthropogenic Pb accumulated in the bogs was calculated by simply adding the mass of anthropogenic Pb for each peat slice over the length of each core. Cumulative, anthropogenic Pb calculate d in this way ranged from 1.0 to 9.7 g/m(2) and showed pronounced regional differences: the site south of the Alps (Gola di Lago in Canton Ticino) wit h direct exposure to the heavily industrialized region of northern Italy re ceived nearly LO times more anthropogenic Pb as the sites in more remote al pine regions (Schopfenwaldmoor in Canton Berne, and Mauntschas in Canton Gr isons). The approach used here to calculate cumulative, anthropogenic, atmo spheric Pb (CAAPb) is simple and robust, independent of the chronology of P b deposition, and makes no assumptions about the immobility of Pb within th e peat profile. Given the worldwide distribution of peat bogs, it should be possible to undertake continental and global inventories of atmospheric me tal deposition, for both the natural and anthropogenic components of most t race metals of environmental interest. (C) 2000 Elsevier Science B.V. All r ights reserved.