DEPOSITION AND FATE OF LEAD IN A FORESTED CATCHMENT, LESNI POTOK, CENTRAL CZECH REPUBLIC TOMÁŠ NAVRÁTIL 1,2* , MAREK VACH 1 , PETR SK ˇ RIVAN 1 , MARTIN MIHALJEVI ˇ C 2 and IRENA DOBEŠOVÁ 1 1 Geological Institute, Academy of Science, Czech Republic; 2 Faculty of Science, Charles University, Prague ( * author for correspondence, e-mail: navratilt@gli.cas.cz; phone: +420-2-33087222; fax: +420-2-20922670) (Received 20 August 2002; accepted 8 April 2003) Abstract. The deposition of trace elements and their fate in a forest ecosystem has been monitored at the experimental site, Lesni Potok catchment (LP), with granite bedrock. The catchment is located 30 km ESE from Prague. Annual bulk Pb-deposition flux F Pb was 3.41 kg km -2 a -1 in 1994 and gradually decreased to 0.49 kg km -2 a -1 in 2001. The decrease is comparable with those observed in Germany and in the U.S.A. in the 1970s and 1980s. The total sales ban of leaded gasoline in the Czech Republic since January 2001 was accompanied by a pronounced decrease of F Pb in a single year. The residual Pb-deposition flux is assigned to both the long-range transport of fine- grained vehicular lead aerosol (with a long residence time in the atmosphere) and to the emissions from power plant boilers burning lignite mined in the Czech northwest coal basin. The F Pb of lead correlates strongly with those of As, Cd, Cu, Zn and Be, the typical metals in coal fly ash, at two monitored sites. Topsoil horizons contain elevated concentrations of Pb (53–67 mg kg -1 ), which are of anthropogenic origin. Soils in the riparian areas contain increased concentrations of Pb when compared to soils on the hillslope areas. Significant amounts of Pb were found on a stream substrate and Fe-precipitate sampled from the stream. Low concentrations of Pb in bark and bole wood suggest that the uptake of Pb by vegetation is negligible. The very small surface water outputs (average of 0.002 kg km -2 a -1 ) compared to inputs (average of 1.890 kg km -2 a -1 ) from the LP catchment indicate an ongoing accumulation of Pb in a forested landscape. Keywords: biogeochemical cycle, catchment, central Czech Republic, deposition, lead, monitoring, Pb, precipitation 1. Introduction The entire solid surface of our planet is contaminated by anthropogenic (mostly vehicular) lead (Pb). Recurring problems with this toxic trace metal in our environ- ment are well known and widely discussed in the literature. Research of Antarctic ice indicates that the current concentration of Pb is 2 pg Pb g -1 , whereas during most of Holocene it was approximately 0.4 pg Pb g -1 (Boutron and Patterson, 1986). The authors postulate that >99% of the tropospheric Pb in mid-1960s in the northern hemisphere originated from human activities. Worldwide sources of anthropogenic Pb emissions to the atmosphere (in descending order) are vehicular Water, Air, and Soil Pollution: Focus 4: 619–630, 2004. © 2004 Kluwer Academic Publishers. Printed in the Netherlands.