Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 7 1 2007 10.5194/acpd-7-995-2007 http://www.atmos-chem-phys-discuss.net/7/995/2007/ http://www.atmos-chem-phys-discuss.net/7/995/2007/acpd-7-995-2007.html http://www.atmos-chem-phys-discuss.net/7/995/2007/acpd-7-995-2007.pdf 995 1016 2007-01-22 Iodine and Bromine speciation in snow and the effect of elevation B. S. Gilfedder Benjamin.gilfedder@ugc.uni-heidelberg.de M. Petri H. Biester Institut für Umweltgeochemie, Neuenheimer Feld 236 69120, Heidelberg, Germany Bodensee-Wasserversorgung, Sipplingen Laboratory, Germany Iodine is an essential trace element for all mammals and may also influence climate through new aerosol formation. Atmospheric bromine cycling is also important due to its well-known ozone depletion capabilities. Despite precipitation being the ultimate source of iodine in the terrestrial environment, the processes effecting the distribution, speciation and transport of these elements are relatively unknown. The aim of this study was to determine the effect of orographic lifting on iodine concentrations and also quantify inorganic and organic iodine and bromine species. Snow samples were collected over an altitude profile (~800 m) from the northern Black Forest and were analysed (IC-ICP-MS) for iodine and bromine species and trace metals (ICP-MS). All elements and species showed a significant (r²>0.65) inverse relationship with altitude despite the short (5 km) horizontal distance of the transect. In fact, total iodine more than halved (38 to 13 nmol/l) over the 800 m height change. 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