Lead fluxes, isotopic and concentration profiles in a peat deposit near a lead smelter (Pribram, Czech Republic)

摘要

The content and the isotopic composition of lead (Pb) were studied in a peat deposit on the ridge of the Brdy Hills, in the vicinity of the Pfibram metallurgical works, in the Czech Republic. Quadrupole ICP MS was employed to determine the elemental composition and ~(206)Pb/~(207)Pb and ~(208)Pb/~(206)Pb isotope ratios. The individual layers were dated using a spectrometric measurement of the ~(210)Pb activity. The historical time period covered by the studied cores reached back to the 18th century. The Pb concentration in the studied profiles varied from 10 to 550 mg kg~(-1). The ~(206)Pb/~(207)Pb ratio varied in the range from 1.154 to 1.194 in the individual parts of the profile. The metallurgy of the Pb ores (~(206)Pb/~(207)Pb ～ 1.16), lithogenic Pb (~(206)Pb/~(207)Pb ～ 1.2), metallurgical processing of automobile batteries (~(206)Pb/~(207)Pb ～ 1.17) and the combustion of coal (~(206)Pb/~(207)Pb ～ 1.17-1.19) yield isotopic signatures that determine the isotope compositions of the individual profiles. Deposition rates between 15 mg m~(-2) year~(-1) at the beginning of the 19th century and 320 mg m~(-2) year~(-1) in the 1980s were determined in the dated profiles. The increased deposition rates determined on the dated profiles correspond to the increasing production of Pb ores in the Pfibram mining area at the turn of the 19th and 20th centuries. The maximum for metallurgical production corresponds to the highest deposition rates recorded in 1960s and 1970s. The current deposition rate of 5-89 mg m~(-2) year~(-1) Pb is related to erosion of contaminated soils and waste dumps.