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

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dc.citation.doiDOI: 10.17159/sajs.2017/20160237en_ZA
dc.citation.issue1-2en_ZA
dc.contributor.authorHumphries, M.S.
dc.contributor.authorMcCarthy, T.S.
dc.contributor.authorPillay, L.
dc.date.accessioned2017-10-13T14:12:18Z
dc.date.available2017-10-13T14:12:18Z
dc.date.issued2017-01
dc.description.abstractWetlands 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.description.librarianEM2017en_ZA
dc.identifier.citationHumphries, 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 #2016-0237en_ZA
dc.identifier.issn0038-2353 (Print)
dc.identifier.issn1996-7489 (Online)
dc.identifier.urihttp://hdl.handle.net/10539/23247
dc.journal.titleSOUTH AFRICAN JOURNAL OF SCIENCEen_ZA
dc.journal.volume113en_ZA
dc.language.isoenen_ZA
dc.publisherAcademy of Science of South Africa (ASSAf)en_ZA
dc.rights© 2017. The Author(s). Published under a Creative Commons Attribution Licence.en_ZA
dc.subjectGold miningen_ZA
dc.subjectKlip River wetlanden_ZA
dc.subjectMetal sequestrationen_ZA
dc.subjectRemediationen_ZA
dc.subjectWater qualityen_ZA
dc.subjectacid mine drainageen_ZA
dc.subjectconcentration (composition)en_ZA
dc.subjectenrichmenten_ZA
dc.subjectgeochemical surveyen_ZA
dc.subjectgold mineen_ZA
dc.subjectimmobilizationen_ZA
dc.subjectpeaten_ZA
dc.subjectpollutant sourceen_ZA
dc.subjectsequestration (chemistry)en_ZA
dc.subjectwater managementen_ZA
dc.subjectwater pollutionen_ZA
dc.subjectwetlanden_ZA
dc.subjectCentral Rand Goldfielden_ZA
dc.subjectGautengen_ZA
dc.subjectJohannesburgen_ZA
dc.subjectKlip Riveren_ZA
dc.subjectSouth Africaen_ZA
dc.subjectWitwatersranden_ZA
dc.titleAttenuation of pollution arising from acid mine drainage by a natural wetland on the Witwatersranden_ZA
dc.typeArticleen_ZA
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