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Mechanisms of arsenic attenuation in acid mine drainage from Mount Bischoff, western Tasmania


Gault, AG and Cooke, DR and Townsend, AT and Charnock, JM and Polya, DA, Mechanisms of arsenic attenuation in acid mine drainage from Mount Bischoff, western Tasmania, Science of the Total Environment, 345, (1-3) pp. 219-228. ISSN 0048-9697 (2005) [Refereed Article]

DOI: doi:10.1016/j.scitotenv.2004.10.030


There is a dearth of research concerning the geochemistry of arsenic in acid mine drainage (AMD) in western Tasmania. To help address this, the controls on the mobility and fate of arsenic in AMD and its associated sediment at the Mount Bischoff mine site in western Tasmania were investigated. AMD issuing from the adit mouth contained dissolved arsenic and iron concentrations of 2.5 and 800 mg L-1, respectively. The aqueous concentration of both arsenic and iron decreased markedly over a 150-m stretch from the adit mouth due to precipitation of hydrous ferric oxides (HFO) and jarosite, both of which are effective scavengers of arsenic. Microwave-assisted digestion of the sediment collected at the adit mouth revealed that the arsenic concentration exceeded 1%. Sequential extraction of this sediment showed that the bulk of arsenic was associated with amorphous and crystalline hydrous oxides of Al and/or Fe. Extended X-ray absorption fine structure (EXAFS) analysis indicated that the solid phase arsenic exists as As(V). EXAFS data were consistent with arsenate tetrahedra substituting for sulphate in jarosite and with corner-sharing complexes adsorbed on ferric oxyhydroxide octahedra. Erosional transport of AMD sediment downstream to higher pH waters may increase the mobility (and hence bioavailablity) of arsenic through dissolution of As-rich jarosite. © 2004 Elsevier B.V. All rights reserved.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Geochemistry
Research Field:Geochemistry not elsewhere classified
Objective Division:Mineral Resources (Excl. Energy Resources)
Objective Group:Environmentally sustainable mineral resource activities
Objective Field:Environmentally sustainable mineral resource activities not elsewhere classified
UTAS Author:Cooke, DR (Professor David Cooke)
UTAS Author:Townsend, AT (Associate Professor Ashley Townsend)
ID Code:39063
Year Published:2005
Web of Science® Times Cited:62
Deposited By:Centre for Ore Deposit Research - CODES CoE
Deposited On:2005-08-01
Last Modified:2007-10-17

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