Title: Influence of ripening on pHstat leaching of heavy metals from dredged sediments
Authors: Cappuyns, ValĂ©rie ×
Swennen, Rudy
Devivier, Anne #
Issue Date: 2004
Publisher: Royal Society of Chemistry
Series Title: Journal of Environmental Monitoring vol:6 issue:9 pages:774-781
Abstract: The influence of oxidation and ripening on the kinetics of heavy metal release from anoxic sediments was investigated by means of porewater analysis and pHstat leaching tests. During simulated land disposal of an anoxic river sediment, a considerable heavy metal (Cd, Zn and Ni) release into the porewater was observed after 25 days of exposure of the sediment to the air. The release kinetics of Cd and Zn during pHstat leaching indicated that their release was related to the oxidation of Cd- and Zn-sulfides. It was not completely clear whether the release of Ni was due to the oxidation of Ni-sulfides or to the introduction of H+(generated by the oxidation of sulfides or introduced by titration). The release of Cu seemed to be explained by the oxidation of both Fe-sulfides and Cu-sulfides. As such, pHstat experiments provided an indirect way to assess the mineralogy of the anoxic sediment. During ripening of the sediment, the release rate of Zn and Cd in pHstat leaching tests increased. For Ni, however, a similar release pattern was observed in the anoxic sediment and in the ripened sediments. Two weeks drying at 100 °C resulted in an increase in the leachability of Cu. Nevertheless, at pH 4 and 6, the thermally treated sediment displayed a slower leaching of Cd and Zn than the ripened sediment. Although thermal treatment is often used to simulate ageing in soils, it cannot be used to simulate ripening of anoxic sediments
ISSN: 1464-0325
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Division of Geology
Research Centre for Economics and Corporate Sustainability, Campus Brussels
Faculty of Economics and Business (FEB) - miscellaneous
× corresponding author
# (joint) last author

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