The impact of power station emissions on surface water quality in Mpumalanga: the case of Majuba Power Station

• Main Author: Molebatsi, Nompumelelo
• Published: 2009
• Subjects: Water quality; Water pollution; Power plants; Mpumalanga (South Africa)
• Online Access: http://hdl.handle.net/10210/2015

M.Sc. === The impact of air pollution by power stations on water quality, just like any other source of water pollution, is an issue of concern for all the water users since any degradation in water quality affects the water's suitability for use. The study area in which Majuba power station is located was chosen because it is in an area free of industrialisation, and is also part of the Vaal catchment. This catchment area is very important because of its water supply for Gauteng province and provides an ideal opportunity to monitor surface water pollution from atmospheric sources such as power stations. The purpose of this research is to investigate the chemical, physical and biological quality of surface water in the vicinity (within a 31 kilometre radius) of Majuba power station. The study will determine whether this power station is causing any salinity and acidity problems at the chosen sampling sites. Salinity and acidity are water quality problems associated with atmospheric pollution. The aim of the study is to determine whether proximity to Majuba power station has an effect on the surrounding surface water quality. The research was conducted by means of water quality sampling, analyses and assessment. Water quality samples were taken from six sites (Majuba 1 to Majuba 6) in the vicinity of Majuba power station over a period of three years (1997 to 1999). The approach was to take four samples in a year coinciding with the four seasons of the year. Due to logistical problems only two sampling trips were undertaken, during 1997. In 1998 and 1999 the full four sampling trips were undertaken however in some instances the river was dry or was flooded hence no samples could be taken at the affected sampling sites (although a trip to the sampling site was made). The biological analyses where done on site using the biomonitoring technique while chemical analyses were performed at the laboratory at Eskom. The biomonitoring assessment was done using the biomonitoring technique. The chemical results were assessed in terms of the suitability for use for the aquatic environment. This was done by using the water quality guidelines for the aquatic environment. The chemical results indicated that in terms of salinity and acidity the site closest to the power station, namely Majuba 1 had the worst water quality of the six sites. Majuba 1 also had the worst results in terms of biomonitoring. Majuba 2 indicated elevated salinity levels. The other four sites, namely Majuba 3 to 6, did not indicate either salinisation or acidification. However, the biomonitoring results at these sites indicated, with the exception of Majuba 4, some deterioration in water quality. Majuba 4 had the best water quality in terms of biomonitoring. Reasons for this could not be determined. At present it is still premature to say whether acidity in the water is a problem. This is a preliminary study and currently a more detailed multidisciplinary study that includes disciplines such as atmospheric deposition, groundwater chemistry, soil profiles and hydrology is being undertaken on the Upper Vaal catchment to comprehensively determine the impact of air pollution from power stations on the surface water quality. The proposal will be presented to the South African Water Research Commission. The ultimate aim of the multidisciplinary study is to inform decision makers in water quality management sector regarding the impact of air pollution on surface water quality, in order for them to put in place abatement technologies or strategies to mitigate surface water quality pollution.