Determination and fractionation of sulphur in a contaminated dredged sediment1

Abstract

Summary-Conversion of sulphur compounds in reduced, contaminated sediments that are brought in upland conditions may largely affect the potential mobility of heavy metal contaminants. We applied selected methods for the determination of total sulphur and sulphur fractions in a contaminated sediment in the reduced state and after gradual drying and oxidation during one month.Dry ashing, followed by ion chromatographic detection, was reliable for the determination of total sulphur. Good recoveries were obtained in both reference samples and spiked samples. Total sulphur was 14.5 ± 0.6 g kg -1 relative to dry sediment.Wet chemical methods that involve the determination of acid-volatile, Zn-HClreducible, chromium-reducible, acetone-soluble and HI-reducible sulphur were used to estimate specific sulphur forms. Results for acetone-soluble sulphur were to high and not consistent with results for other fractions. Major part of sulphur in the sediment (90 %) was inorganic. Sulphides were converted partially to sulphate and to intermediary oxidised sulphur compounds upon oxidation of the sediment. The results suggested that the intermediary oxidised sulphur pool in the reduced sediment (2.5 g kg -1 ) mainly consisted of pyrite, that was not converted during drying and oxidation. No significant changes in organic sulphur were detected.

Effect of Water Table Level on Metal Mobility at Different Depths in Wetland Soils of the Scheldt Estuary (Belgium)

“…Pseudo-total metal contents in the soils were determined by an aqua regia destruction (Ure 1990) and analysed with inductively coupled plasma optical emission spectrometry (ICP-OES, Varian Vista MPX, Varian, Palo Alto, CA, USA). AVS contents were determined on fresh soil samples by conversion of sulphide to H 2 S and absorption in a Zn-acetate solution, followed by a back titration, as described by Tack et al (1997). The pH was measured in a 1/5 soil/distilled water suspension after equilibration during 18 h (Van Ranst et al 1999).…”

Effect of decomposing litter on the mobility and availability of metals in the soil of a recently created floodplain

“…Results varied from 92.5 to 101.7% of the certified aqua regia extractable values. Acid volatile sulphide (AVS) was determined by transformation of sulphide to H 2 S and absorption in a Zn-acetate solution, followed by a back-titration (Tack et al, 1997). The pH was measured in a 1/5 soil/distilled water suspension after equilibration during 18 h (Van Ranst et al, 1999).…”

“…This confirms that Fe and Mn might indeed have been subject to other processes, such as a re-adsorption by the soil or biotic compartments or migration to more oxic parts of the experimental setup and subsequent precipitation as oxides. Another possibility is that sulphides were formed which are not determined in the operational AVS analysis procedure, such as pyrite (Tack et al, 1997;Billon et al, 2001). Moreover, sulphide losses due to partial oxidation of the soil between sampling and analysis might have resulted in a discrepancy between the sulphide amounts which were present and those which were measured.…”

Bioaccessible heavy metals‐sediment particles from Reconquista River induce lung inflammation in mice

“…This oxidation noticeably increases the bioavailability of heavy metals [13][14][15]. matter present in the sediment quickly occurs as the result of the activity of the autotrophic sulfur-oxidizing bacteria and heterotrophic aerobes.…”