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Vojtech Ettler, Charles University in Prague (Czech Republic)
Martin Mihaljevic, Charles University in Prague (Czech Republic)
Michael Komarek, Czech University of Life Sciences (Czech Republic)
Ondrej Sebek, Charles University in Prague (Czech Republic)
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Lead isotopes were found to be a suitable tool for understanding the extent of the anthropogenic impact on environmental systems (Komárek et al., 2008, Environment International, doi:10.1016/j.envint.2007.10.005). In this study, soils and stream sediments from the mining/smelting district of Pribram, Czech Republic, were studied to determine the degree, sources and dispersal of metal contamination using a combination of classical geochemical and Pb isotopic analyses. The Pb isotopic composition (206Pb/207Pb and 208Pb/206Pb) in smelter-impacted soils was measured using a quadrupole-based ICP-MS. The results were compared with the Pb isotopic composition of bedrocks and waste materials from Pb metallurgy (smelting slags from historically different technologies, air-pollution-control residues from the Pb smelter) and Pb mining (galena). The isotopic composition of soils confirms the predominant role of metallurgy on the general pollution in the area. The highly contaminated soils from the vicinity of the smelter contain up to 35 300 mg Pb/kg and exhibit an isotopic composition close to that of car battery processing (206Pb/207Pb up to 1.177). A coupled concentration/isotopic study of soil profiles showed that the smelter-induced pollution had penetrated even to the mineral soil horizons, indicating an important vertical mobility of Pb contaminant within the soil profile. The calculated downward penetration rate of Pb in soils ranges from 0.3 to 0.36 cm/y (Ettler et al., 2004, Analytical and Bioanalytical Chemistry 378, 311-317). Lead isotopic analysis indicates that the predominant source of stream sediment contamination is historic Pb-Ag mining and primary Pb smelting (206Pb/207Pb = 1.16), while the role of secondary smelting (car battery processing) is negligible (Ettler et al., 2006, Environmental Pollution, 142, 27-35). The highest metal concentrations were found 3-4 km downstream from the main polymetallic mining site (9 800 mg Pb/kg, 26 039 mg Zn/kg, 316.4 mg Cd/kg, 256.9 mg Cu/kg). The calculated enrichment factors (EFs) confirmed the extreme degree of contamination by Pb, Zn and Cd (EF>40).
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