Chemical composition of fog and cloud water at the Erzgebirge summit, Germany Stephanie Schüttauf*, Frank Zimmermann and Jörg Matschullat Interdisciplinary Environmental Research Center, TU Bergakademie Freiberg, D-09599 Freiberg, Germany; * e-mail: stephanie.schuettauf@student.tu-freiberg.de Background Against most assumptions, toxic components are still highly concentrated in fog water. The sulfate decline is weaker than predicted. Nitrate concentrations increased. This study delivers new data on the chemical composition of fog and cloud water. Based on passive string collector samples from Zinnwald-Georgenfeld (ZIW 877 m a.s.l.) and Conclusion On focus were the seasonal and longer timescale variability of fog and cloud water chemical composition. Both sampling sites showed similar concentrations (Fig.1). The seasonal development of selected ions NO3-, NH4 and Cl- comes up to our expectations. SO42- showed consistent concentrations within the year (Fig.2). Related to trace metals, Al, Zn, Pb, and Cu showed the highest concentrations at ZIW; As, Ni, Cr, and Cd were also detected (Fig.3). The concentrations of the dominant TM´s differed considerably between the two sampling periods (Fig.5). Comparable background concentrations (Mt. Brocken) were excessed as well as undershooted. The development for ions within the last decade display higher concentrations for NO3-, SO42- and NH4+ (Fig.4). This contradicts decreasing emissions in Saxony and needs further investigations. Fichtelberg Oberwiesental (FIB 1,214 m a.s.l.), major ions and trace metals were quantified by ion chromatography and ICP-MS. 69 different fog events were gathered in three sampling periods in 2009 and 2010 (1.MP, 2.MP, 3.MP). Quality control included reference materials, comparing calculated vs. measured conductivity, and ionic balances for each sample. Fig.2 Seasonal variability of Cl- (red), NO3- (purple), SO42- (green) and NH4+ (dark blue), at FIB [µeq/l] Results Fig.1 Ionic concentration [µeq/l] for FIB and ZIW Fig.3 Trace metal distribution in fog water [µg/l] F- Cl- NO3- SO42- Na+ NH4+ K+ Ca2+ Mg2+ Fig.5 Development of Pb (dark blue), Zn (red), Al (purple) and Cu (green) concentrations for ZIW1 and ZIW3 and equivalent concentrations for Mt.Brocken[1] Fig.4 Trend of the ionic composition of fog water in the Erzgebirge Ref. [1] Plessow K. et al. (2001) Time study of trace elements and major ions during two cloud events at the Mt. Brocken. Atmos. Environ. 35: 367-378; [2] Lange C. et al. (2003) Fog frequency and chemical composition of fog water- a relevant contribution to atmospheric deposition in the easthern Erzgebirge, Germany. Atmos. Environ. 37: 3731-3739