In order to estimate atmospheric metal deposition in Southern Europe since the beginning of the Industrial Period (~1850 AD), concentration profiles of Pb, Zn and Cu were determined in four 210Pb-dated peat cores from ombrotrophic bogs in Serra do Xistral (Galicia, NW Iberian Peninsula). Maximum metal concentrations varied by a factor of 1.8 for Pb and Zn (70 to 128μggμ1 and 128 to 231μggμ1, respectively) and 3.5 for Cu (11 to 37μggμ1). The cumulative metal inventories of each core varied by a factor of 3 for all analysed metals (132 to 329μgcmμ2 for Pb, 198 to 625μgcmμ2 for Zn and 22 to 69μgcmμ2 for Cu), suggesting differences in net accumulation rates among peatlands. Although results suggest that mean deposition rates vary within the studied area, the enhanced 210Pb accumulation and the interpretation of the inventory ratios (210Pb/Pb, Zn/Pb and Cu/Pb) in two bogs indicated that either a record perturbation or post-depositional redistribution effects must be considered. After correction, Pb, Zn and Cu profiles showed increasing concentrations and atmospheric fluxes since the mid-XXth century to maximum values in the second half of the XXth century. For Pb, maximum fluxes were observed in 1955-1962 and ranged from 16 to 22mgmμ2yrμ1 (mean of 18±1mgmμ2yrμ1), two orders of magnitude higher than in the pre-industrial period. Peaks in Pb fluxes in Serra do Xistral before the period of maximum consumption of leaded petrol in Europe (1970s-1980s) suggest the dominance of local pollutant sources in the area (i.e. coal mining and burning). More recent peaks were observed for Zn and Cu, with fluxes ranging from 32 to 52mgmμ2yrμ1 in 1989-1996, and from 4 to 9mgmμ2yrμ1 in 1994-2001, respectively. Our results underline the importance of multi-core studies to assess both the integrity and reliability of peat records, and the degree of homogeneity in bog accumulation. We show the usefulness of using the excess 210Pb inventory to distinguish between differential metal deposition, accumulation or anomalous peat records. © 2010 Elsevier B.V.
|Journal||Science of the Total Environment|
|Publication status||Published - 1 Jan 2010|
- Metal pollution
- Peat bogs
- Spatial variability