Sulfate 34S/32S in the River Elbe and its Tributaries

Andreas Diener Institut für Geologie, Ruhr-Universität Bochum, D-44780 Bochum, Germany


Ján Veizer Institut für Geologie, Ruhr-Universität Bochum, D-44780 Bochum, Germany

and Department of Geology, University of Ottawa, Ottawa KIN 6N5, Canada


The 34S/32S value of the dissolved sulfate reflects the composition of the input sulfur, primarily sedimentary marine sulfates, sulfate in precipitation and groundwaters, and sulfate from oxidation of sulfides. The aim of this study has been to utilize sulfur isotopes in order to decipher sulfur sources in the river Elbe and its major tributaries.

Samples and Preparation Techniques

The entire Elbe, except for its tidal portion, has been sampled at 45 points in the winter of 1991 and spring and fall of 1992. Simultaneously, 9 tributaries have been sampled above the confluence with the Elbe. Monthly sampling for one year has been undertaken for the Elbe at Havelberg as well as for the river Havel. 2-3 l of water were prefiltered, set at pH 1-2 and the dissolved sulfate precipitated as BaSO4 by addition of BaCl2. The precipitated sulfate was filtered out and dried at 400°C. 122 samples of SO2 gas were measured for d34S(CDT).

Results and Discussion

Regardless of the season, the d34S(CDT) of dissolved sulfate in the Elbe increases downstream from 1-2 ” to 5-7 ”, with the spring trend being some 1-2 ” lighter than in the winter and fall. The tributaries have mostly heavier d34S values than the Elbe. The overall down-river trend is thus predominantly the result of inputs from the isotopicaly heavy tributaries. The bulk of dissolved sulfate in the Elbe originates from mining, particularly of marine Zechstein evaporites with d34S(CDT) of 9.7-12.6 ” for the Hauptanhydrit (Kampschulte et al., 1995). This sulfate is introduced predominantly by the river Saale , with sulfate concentrations of 50 ppm in the spring and up to 400 ppm in the fall and winter. The proportion of sulfate-S originating from oxidation of sulfides (d34S(CDT) ~ -23 ”) (Schulte et al., 1996) and from precipitation and/or groundwater (d34S(CDT) ~ 4 ”) (Schroll and Pak, 1978) is of subordinated importance. Accepting the last two sources contribute less 10% to the sulfur budget , the resulting ternary system is controlled principally by mixing of sulfate rich waters from mining regions with sulfate poor precipitation. One partial exception is the section immidiately downstream from the Czech border that shows deviations, of ~ 2 ”, towards the 34S depleted values, possibly related to water derived from the former uranium mines. Such waters have d34S(CDT) of -7.5 to -4 ” suggesting that oxidation of pyrite is their main source of sulfur.


The bulk sulfate-S load in the Elbe is derived mostly from mined salts released into the rivers by precipitation.


Kampschulte, A., Buhl, D. & Strauss, H., Terra Nova 7, 325 (1995).

Schroll, E. & Pak, E., Proc. of Advisory Group Meeting, Vienna 17.-20.06.1986, IAEA, Vienna, 15-18 (1978).

Schulte, U., Bergmann, A., Oberman, P. & Strauss, H., J. Conf. Abs. 1, (1996).