title: Regional and temporal variability of the isotope composition (O, S) of atmospheric sulphate in the region of Freiberg, Germany, and consequences for dissolved sulphate in groundwater and river water.
abstract: The isotope composition of dissolved sulphate and strontium in atmospheric deposition, groundwater, mine water and river water in the region of Freiberg was investigated to better understand the fate of these components in the regional and global water cycle. Most of the isotope variations of dissolved sulphates in atmospheric deposition from three locations sampled bi- or tri-monthly can be explained by fractionation processes leading to lower [Formula: see text] (of about 2-3‰) and higher [Formula: see text] (of about 8-10‰) values in summer compared with the winter period. These samples showed a negative correlation between [Formula: see text] and [Formula: see text] values and a weak positive correlation between [Formula: see text] and [Formula: see text] values. They reflect the sulphate formed by aqueous oxidation from long-range transport in clouds. However, these isotope variations were superimposed by changes of the dominating atmospheric sulphate source. At two of the sampling points, large variations of mean annual [Formula: see text] values from atmospheric bulk deposition were recorded. From 2008 to 2009, the mean annual [Formula: see text] value increased by about 5‰; and decreased by about 4‰ from 2009 to 2010. A change in the dominating sulphate source or oxidation pathways of SO(2) in the atmosphere is proposed to cause these shifts. No changes were found in corresponding [Formula: see text] values. Groundwater, river water and some mine waters (where groundwater was the dominating sulphate source) also showed temporal shifts in their [Formula: see text] values corresponding to those of bulk atmospheric deposition, albeit to a lower degree. The mean transit time of atmospheric sulphur through the soil into the groundwater and river water was less than a year and therefore much shorter than previously suggested. Mining activities of about 800 years in the Freiberg region may have led to large subsurface areas with an enhanced groundwater flow along fractures and mined-refilled ore lodes which may shorten transit times of sulphate from precipitation through groundwater into river water.
authors.affiliation: Institute of Mineralogy, Technische Universität Bergakademie Freiberg, Freiberg, Germany. tichomir@mineral.tu-freiberg.de
authors.forename: Marion
authors.initials: M
authors.lastname: Tichomirowa
authors.forename: Claudia
authors.initials: C
authors.lastname: Heidel
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002947:Cities; D004784:Environmental Monitoring; D005858:Germany; D060587:Groundwater / Q000737:chemistry; D008906:Mining; D010103:Oxygen Isotopes / Q000032:analysis; D045483:Rivers / Q000737:chemistry; D012621:Seasons; D013324:Strontium / Q000032:analysis*; D013325:Strontium Isotopes / Q000032:analysis; D013431:Sulfates / Q000032:analysis; D013460:Sulfur Isotopes / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*; D015032:Zinc / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D010103:Oxygen Isotopes; D013325:Strontium Isotopes; D013431:Sulfates; D013460:Sulfur Isotopes; D014874:Water Pollutants, Chemical; D015032:Zinc; D013324:Strontium