title: The fate of atmospherically derived Pb in Central European catchments: insights from spatial and temporal pollution gradients and Pb isotope ratios.
abstract: Soils in polluted regions are generally regarded as a delayed, long-lasting source for Pb contamination of aquatic systems. Lead deposited on topsoil is slowly transported downward with particulate and colloidal organic matter, driven by infiltrating precipitation. Then, Pb is tightly retained in mineral soil. Lead export from catchments is extremely low and decoupled from the atmospheric input. We tested this hypothesis in 11 small catchments, differing in pollution levels. Input/ouput Pb fluxes were monitored for 14-15 years in an era of decreasing industrial Pb emission rates. Between 1996/1997 and 2010, Pb deposition fluxes decreased significantly, on average by 80%. At the beginning of the monitoring, Pb export constituted 2 to 58% of Pb input. At the end of the monitoring, Pb export constituted 2 to 95% of Pb input. Highly polluted sites in the northeast exported significantly more Pb than less polluted sites further south. The (206)Pb/(207)Pb isotope ratios of runoff (1.16) were identical to those of topsoil and present-day deposition, and different from mineral soil and bedrock. Lead isotope systematics and between-site flux comparisons indicated that a portion of the incoming Pb had a relatively short residence time in the catchments, on the order of decades.
authors.affiliation: Czech Geological Survey , Geologicka 6, 152 00 Prague 5, Czech Republic.
authors.forename: Leona
authors.initials: L
authors.lastname: Bohdalkova
authors.forename: Martin
authors.initials: M
authors.lastname: Novak
authors.forename: Marketa
authors.initials: M
authors.lastname: Stepanova
authors.forename: Daniela
authors.initials: D
authors.lastname: Fottova
authors.forename: Vladislav
authors.initials: V
authors.lastname: Chrastny
authors.forename: Jitka
authors.initials: J
authors.lastname: Mikova
authors.forename: Ales A
authors.initials: AA
authors.lastname: Kubena
mesh_terms: D000393:Air Pollutants / Q000032:analysis; D001272:Atmosphere / Q000737:chemistry*; D018153:Czech Republic; D004787:Environmental Pollution / Q000032:analysis*; D005843:Geography; D007554:Isotopes / Q000032:analysis; D007854:Lead / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D013997:Time Factors
chemical_list: D000393:Air Pollutants; D007554:Isotopes; D012989:Soil Pollutants; D007854:Lead