Abstract
M.Sc. (Aquatic Health)
The study and monitoring of our rivers are essential for management of our scarce fresh water resources. Several factors affect water health of South African fresh water resources of which the most serious one is mining. Mining activities have negatively affected several catchments in SA, especially in Gauteng and Mpumalanga. The Witwatersrand has long been affected by Acid Mine Drainage (AMD) leaching from slimes dams, rock piles and mine dumps. More recently, the rivers on the West Rand have been affected by AMD issuing from disused shafts after the last active mines stopped pumping ground water from the mine void. The aquatic health of the rivers on the West Rand has been seriously compromised because of AMD entering the wetlands near the mines. Over the past decades, several attempts have been made by mines to treat the AMD but with limited success. The main aim is to attempt to neutralise the AMD with lime, which results in the production of large quantities of sulphate salts while most of the metals that are associated with AMD, are still in the water. The combination of sulphuric acid, sulphate and metals has a devastating effect on the fauna, flora and humans in the regions affected by AMD. This study was done on the aquatic health of the Tweelopiespruit, Rietspruit and Bloubankspruit, which form one of the main river systems on the West Rand. This study shows that although there was an improvement in the pH of the river system over the past decade thanks to the treatment of the AMD at Harmony Gold Mine, there are still AMD associated factors such as extremely high levels of sulphate and metals in the river system which impact negatively on the ecology. This study contributes to our knowledge of the dynamics of this river system, the information gained will be used in future monitoring studies, and management plans for this river system.