Mercury transformations in resuspended contaminated sediment controlled by redox conditions, chemical speciation and sources of organic matter

Abstract

Mercury (Hg) contaminated sediments can be significant sources of Hg in aquatic ecosystems and, through re-emission processes, to the atmosphere. Transformation and release of Hg may be enhanced by various sediment perturbation processes, and controlling biogeochemical factors largely remain unclear. We investigated how rates of Hg transformations in pulp-fiber enriched sediment contaminated by Hg from chlor-alkali industry were controlled by (i) transient redox-changes in sulfur and iron chemistry, (ii) the chemical speciation and solubility of Hg, and (iii) the sources and characteristics of organic matter (OM). Sediment-bottom water microcosm systems were exposed to four combinations of air and nitrogen gas for a total time of 24 h. The treatments were: 24 h N-2, 0.5 h air + 23.5 h N-2, 4 h air + 20 h N-2 and 24 h of air exposure. As a result of these treatments, microcosms spanned a wide range of redox potential, as reflected by the dissolved sulfide concentration range of

Keywords

Mercury; Chemical speciation; Redox oscillation; Organic matter; Methylation; Demethylation; Reduction; Sediment resuspension

Published in

Geochimica et Cosmochimica Acta
2018, volume: 220, pages: 158-179

SLU Authors

• Zhu, Wei

  • Umeå University

• Song, Yu

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

• Adediran, Gbotemi

  • Umeå University

• Jiang, Tao

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

• Skyllberg, Ulf

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Geosciences, Multidisciplinary
Geochemistry
Environmental Sciences

Publication identifier

• DOI: https://doi.org/10.1016/j.gca.2017.09.045

Permanent link to this page (URI)

https://res.slu.se/id/publ/90997