Determination of total sulfur in freshwater sediments by ion chromatography

• Published in: Water research (Oxford) 1989-07, Vol.23 (7), p.853-859
• Main Authors: Hordijk, Cornelis A., van Engelen, Johannes J.M., Jonker, Frank A., Cappenberg, Thomas E.
• Format: Article
• Language: English
• Subjects: Analysis methods; Applied sciences; Exact sciences and technology; Freshwater; freshwater sediments; ion chromatography; Pollution; Soil and sediments pollution; sulfur accumulation; total sulfur
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/0043-1354(89)90009-2

A method to determine total sulfur in freshwater sediments has been developed. This method involves oxidation of the sediment by a half fusion reaction with a Na 2CO 3/KNO 3 mixture, purification with cation exchange chromatography and detection of the released sulfate by indirect photometric chromatography. Total sulfur estimates from the sediment of Lake Vechten were similar to those obtained by induced coupled plasma spectrometry ( r = 0.998, n = 35) and roentgen-fluorescence spectrometry. The method gives reliable results with difficult-to-oxidize RSR bonds such as those present in methionine. The detection of sulfate by the sensitive technique of ion-chromatography (detection limit 5 pmol) enables sulfur analysis in μg quantities. The method can be combined with trace determination of radioactive 35S. Total sulfur in the 47-year old sediment of Lake Vechten varied between 1100 and 1600 mg 1 −1 wet sediment, representing approx. 0.4% of the dry weight. The total sulfur pool is comprised of 3% elemental sulfur, 8% pyrite, 60% acid volatile sulfide and 12% ester sulfates, leaving 17% non-identified. From a comparison of total sulfur estimates in the 28 cm thick sedimented layer (125 g S m −2), sulfate reduction rates (11.4 g S m −2 year −1) and sedimentation rates (3.21 g S m −2 day −1), it appears that most of the sulfur reduced during the year is re-oxidized.