title: Lead isotope ratios in tree bark pockets: an indicator of past air pollution in the Czech Republic.
abstract: Tree bark pockets were collected at four sites in the Czech Republic with differing levels of lead (Pb) pollution. The samples, spanning 1923-2005, were separated from beech (Fagus sylvatica) and spruce (Picea abies). Elevated Pb content (0.1-42.4 microg g(-1)) reflected air pollution in the city of Prague. The lowest Pb content (0.3-2.6 microg g(-1)) was found at the Kosetice EMEP "background pollution" site. Changes in (206)Pb/(207)Pb and (208)Pb/(206)Pb isotope ratios were in agreement with operation times of the Czech main anthropogenic Pb sources. Shortly after the Second World War, the (206)Pb/(207)Pb isotope ratio in bark pockets decreased from 1.17 to 1.14 and the (208)Pb/(206)Pb isotope ratio increased from 2.12 to 2.16. Two dominant emission sources responsible for these changes, lignite and leaded petrol combustion, contributed to the shifts in Pb isotope ratios. Low-radiogenic petrol Pb ((206)Pb/(207)Pb of 1.11) lead to lower (206)Pb/(207)Pb in bark pockets over time. High-radiogenic lignite-derived Pb ((206)Pb/(207)Pb of 1.18 to 1.19) was detected in areas affected by coal combustion rather than by traffic.
authors.affiliation: Faculty of Natural Sciences, Charles University, Benatska 8, Prague 1, Czech Republic. conkova@chmi.cz
authors.forename: M
authors.initials: M
authors.lastname: Conkova
authors.forename: J
authors.initials: J
authors.lastname: Kubiznakova
mesh_terms: D000397:Air Pollution / Q000032:analysis*; D003031:Coal; D018153:Czech Republic; D004784:Environmental Monitoring; D005843:Geography; D017745:Incineration; D007220:Industrial Waste; D007554:Isotopes / Q000032:analysis* / Q000737:chemistry; D007854:Lead / Q000032:analysis* / Q000737:chemistry; D024301:Plant Bark / Q000737:chemistry*; D001335:Vehicle Emissions
chemical_list: D003031:Coal; D007220:Industrial Waste; D007554:Isotopes; D001335:Vehicle Emissions; D007854:Lead