Pressures affecting freshwater systems and resources
in South Africa: # 2

Pollution: 

The scarcity of water is also exacerbated by pollution of the surface- and ground-water resources. Typical pollutants of South Africa'sfreshwater aquatic environment include industrial effluents; domestic and commercial sewage; acid mine drainage; agricultural runoff, and litter.

Surface water: 

The total amount of waste water (industrial, mining and domestic effluent, and agricultural and urban runoff entering South Africa'ssurface waters is unknown (G Grobler, DWAF, pers. comm.). Diffuse sources of pollution are difficult to quantify and, although point sources can be identified and measured, the data are fragmented.

Water care works

A recent survey by the University of Pretoria (1996) indicated that the total volume of domestic and commercial waste-water treated at water care works throughout the country was about 2 600 MRd^-1 (the volume of a small town's dam).

Acid mine drainage (see Box 3.2) is a recognised problem in the mining areas of the country (especially from coal and gold mines). There is little reliable information on the amount of mining effluent entering water courses. The Minerals Bureau of Statistics has estimated the total number of mines as anything between 1 200 and 2 000, making it difficult to get any reliable estimate of the problem.

To give an indication of the type of pollution pressures on South Africa'swater resources, the Vaal Barrage catchment is taken as an example. Water from the Vaal Barrage catchment supplies the whole of Gauteng, which contributes 37,6 % of the country's GNP and contains 18,1% of the population (Stats SA 1998). The pollution pressures on the catchment include:

• 33 water care works, which treat commercial and domestic effluents. They discharge an average volume of 859 MRd^-1. Problems caused by these effluents are ortho-phosphates, COD ammonium, suspended solids and faecal coliforms (Mr R Heath, Rand Water, pers. comm.). Only 60% of these water care works comply to the 1 mg R^-1 phosphate standard.
  
  
• Fifteen extant gold mines and 29 closed mines are distributed on the North side of the catchment. Acid drainage from these mines is a recognised problem, increasing sulphate, suspended solids and metals (manganese, aluminium, iron) and decreasing the pH of the receiving water resources. An average of 240 MRd^-1 of polluted water has to be pumped to the surface from these mines (Wingrove et al. 1998). It has not proven possible to obtain all the relevant permitting information as to how much of this water is evaporated from ponds, treated or enters water courses untreated.
  
  
• Return flows into streams from industrial plants is not known, although it is estimated that this figure would not exceed 100 MRd^-1 (Mr R Heath, Rand Water, pers. comm.). Problem elements are arsenic, COD, BOD, manganese and suspended solids.
  
  
• Litter, particularly from unserviced informal settlements and recreational visitors is also a problem, although no figures are available.

Of concern to water resource managers are the diffuse sources of pollution that are difficult to quantify. In the past, agricultural runoff, including nutrients, pesticides and herbicides was of major concern. However, the increase in informal settlements, with high poverty levels (see Social Dimensions section) and inadequate sanitation, may become one of the greatest localised pressures on water quality in South Africa.

Groundwater: 

Table 3.2 outlines the nature of a variety of pollutants that may affect groundwater resources. Quantitative information is not available.

>     Freshwater: Pressures continue: #3 ...

There is also information about Freshwater Systems and Resources in the following reports:
Metropolitan reports:
	Cape Metropolitan Council (1998 edition)		Durban Pilot Study
	Greater Johannesburg Metropolitan Council (1999 edition)		Greater Pretoria Metropolitan Council (1999 edition)