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Assessment of the biotic hazard of the acid mine drainage impacted Blesbok Spruit near Witbank, Mpumalanga

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dc.contributor.advisor Prof. J.T. Harmse en_US
dc.contributor.author Hill, Liesl
dc.date.accessioned 2012-09-12T06:44:08Z
dc.date.available 2012-09-12T06:44:08Z
dc.date.issued 2012-09-12
dc.date.submitted 1997-11
dc.identifier.uri http://hdl.handle.net/10210/7515
dc.description M.Sc. en_US
dc.description.abstract The increasing demand for water in South Africa arises from a rapid population growth and from supporting industfial development. Deteriorating water quality limits the sustainable use of water through point and diffuse sources of pollution of macro constituents, metals and biocides. Although water quality monitoring in South Africa has in the past mainly focused on measuring physical and chemical variables, it is now realised that this is not sufficient. Physical and chemical variables on their own cannot provide an accurate account of the general "health" of an aquatic ecosystem. Biological communities on the other hand, are accurate indicators of overall environmental conditions. Water quality management therefore, relies on comparative data for both chemical composition and biological effects. Metals in the environment can originate as point sources, including industrial and mining, effluent, or diffuse sources from geological origin, agricultural activities, acid mine drainage (AMD) and leachate from dumps. Although specific problem areas have been addressed;? AMD is not well documented or quantified in South Africa. The effects thereof on aquatic ecosystems, however, constitute one of South Africa's largest single sources of water pollution. This is certainly the case in the Witbank area of the Mpumalanga Province, where large coal deposits have given rise to extensive mining operations, resulting in severe water quality problems in some rivers in this area which is situated in the upper reaches of the Olifants River. The objective of this study was to determine the potential hazard posed by the surface water and sediment on biota of one of the streams in this area, the Blesbok Spruit, impacted by AMD. The pH values of the surface water and interstitial water of the three sites were below five. A secondary effect of the low pH is an increase in the solubility of metals. The median metal concentrations measured at these sampling sites exceed the South African criteria for Aquatic Ecosystems — in most cases considerably. The high levels of macro constituents can be ascribed to the mining operations, land use activities and urban and rural settlements in the area. Bioassays (laboratory based toxicity tests) performed with Daphnia pulex (waterflea) on the surface and interstitial water of the three sites, indicated acute toxicity at very low dilution concentrations. Chronic toxicity tests performed on the surface water samples indicated an inhibition in the number of young produced per surviving Daphnia adult. Inhibition is a great ecological risk, because species will not survive if populations cannot produce adults. The present study showed that the water quality of the Blesbok Spruit has a severe impact on the aquatic biota and is therefore in need of urgent management measures. It is also clear that sediment cannot be ignored as an aquatic ecosystem component and should form an integral part of water quality monitoring programs in South Africa. en_US
dc.language.iso en en_US
dc.subject Acid mine drainage -- South Africa -- Blesbok Spruit en_US
dc.subject Water -- Pollution -- South Africa -- Blesbok Spruit en_US
dc.subject Stream ecology -- South Africa -- Blesbok Spruit en_US
dc.subject Pollution -- Environmental aspects -- South Africa -- Blesbok Spruit en_US
dc.subject Pollution -- South Africa -- Blesbok Spruit -- Measurement en_US
dc.subject Blesbok Spruit (South Africa) en_US
dc.title Assessment of the biotic hazard of the acid mine drainage impacted Blesbok Spruit near Witbank, Mpumalanga en_US
dc.type Mini-Dissertation en_US

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