Attenuation of pollution arising from acid mine drainage by a natural wetland on the Witwatersrand

Show simple item record Humphries, M.S. McCarthy, T.S. Pillay, L. 2017-10-13T14:12:18Z 2017-10-13T14:12:18Z 2017-01
dc.identifier.citation Humphries, M.S., McCarthy, T.S. and Pillay, L. 2017. Attenuation of pollution arising from acid mine drainage by a natural wetland on the Witwatersrand. SOUTH AFRICAN JOURNAL OF SCIENCE 113 (1-2), Article number #2016-0237 en_ZA
dc.identifier.issn 0038-2353 (Print)
dc.identifier.issn 1996-7489 (Online)
dc.description.abstract Wetlands are well known to be efficient at sequestering pollutants from contaminated water. We investigated metal accumulation in the peats of the Klip River, a natural wetland that has received contaminated water from gold mining operations in Johannesburg for over 130 years. Previous work conducted in the downstream portion identified the wetland as an important system for sequestering metals. We focused on the upstream section of the wetland, more proximal to the source of acid mine drainage, to provide a better understanding of the pollutant sources and the role of the wetland in pollutant attenuation. Geochemical and mineralogical analyses of peat cores revealed considerable metal enrichments in the peat ash, particularly in Co, Ni, Zn, Pb, Cu and U. Metal concentrations are typically between 4 to 8 times higher than those previously reported for the downstream, more distal portion of the wetland. The distribution of metal accumulation within the peat profiles suggests that contamination arises from a combination of sources and processes. Elevated concentrations in the shallow peat are attributed to the input of contaminated surface water via tributaries that drain the Central Rand Goldfield, whereas enrichments in the deeper peat suggest significant sub-surface inflow of contaminated water through the underlying dolomitic rocks. Metal immobilisation occurs through a combination of mechanisms, which include the precipitation of gypsum, metal sulfides, Fe-Mn oxyhydroxides and phosphates. Our study highlights the environmental and economic importance of natural wetland systems which have the ability to accumulate large quantities of metals and thus remediate polluted waters. en_ZA
dc.language.iso en en_ZA
dc.publisher Academy of Science of South Africa (ASSAf) en_ZA
dc.rights © 2017. The Author(s). Published under a Creative Commons Attribution Licence. en_ZA
dc.subject Gold mining en_ZA
dc.subject Klip River wetland en_ZA
dc.subject Metal sequestration en_ZA
dc.subject Remediation en_ZA
dc.subject Water quality en_ZA
dc.subject acid mine drainage en_ZA
dc.subject concentration (composition) en_ZA
dc.subject enrichment en_ZA
dc.subject geochemical survey en_ZA
dc.subject gold mine en_ZA
dc.subject immobilization en_ZA
dc.subject peat en_ZA
dc.subject pollutant source en_ZA
dc.subject sequestration (chemistry) en_ZA
dc.subject water management en_ZA
dc.subject water pollution en_ZA
dc.subject wetland en_ZA
dc.subject Central Rand Goldfield en_ZA
dc.subject Gauteng en_ZA
dc.subject Johannesburg en_ZA
dc.subject Klip River en_ZA
dc.subject South Africa en_ZA
dc.subject Witwatersrand en_ZA
dc.title Attenuation of pollution arising from acid mine drainage by a natural wetland on the Witwatersrand en_ZA
dc.type Article en_ZA
dc.journal.volume 113 en_ZA
dc.description.librarian EM2017 en_ZA
dc.citation.doi DOI: 10.17159/sajs.2017/20160237 en_ZA
dc.citation.issue 1-2 en_ZA

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