INTRODUCTION

Miller (1992) defines pollution as ‘any addition to air, water, soil, or food that threatens the health, survival, capability, or activities of humans or other living organisms’. Pollution is caused when resources are extracted, processed, and when products are manufactured and used. Pollution usually manifests itself in the form of a solid, liquid or a gas emission. Pollutants enter the environment through human activities that impact on the environment and health through chemical, physical or bacteriological factors. Various strategies have been developed to mitigate the effects of pollution. Unfortunately these strategies are expensive to implement and may take years to have the desired effect. In the past most approaches to handling pollution could be summed up by the phrase "dilution is the solution to pollution". However pollution levels have increased so much in amount and toxicity that this approachis no longer acceptable. The key is pollution prevention rather than clean up or control, although the alternative approach of source reduction may be a start to the prevention process. The "Polluter-pays principle", where the polluter should bear the costs of avoiding pollution, or remedying its effects, is increasingly being applied successfully in South Africa.

According to Enviro Facts (1999a), pollution is an unwelcome concentration of substances that are beyond the environment's capacity to handle. These substances are detrimental to people and other living organisms.

In an undisturbed ecosystem, all substances are processed through an intricate network of biogeochemical cycles, such as the nitrogen and carbon cycles. During these cycles, substances are taken up by plants, move through the food chain to larger and more complex organisms, and when the latter die, are decomposed (broken down) into simpler forms to be used again when they are taken up by plants. Biodegradable substances are those that can be broken down by the environment's biological systems. Pollution occurs when the environment becomes overloaded beyond the capacity of these normal processing systems (Enviro Facts, 1999a).

The intention of the Pollution chapter is to highlight the degradation of the urban environment in Greater Johannesburg due to pollution, as well as the state, impact and responses thereto. The main focus is on pollution monitoring. There are a number of strategic visions stating the need for the prevention of pollution, but with few implementation actions. The Pollution chapter gives an overview of the current state of pollution in Johannesburg with a specific focus on air, water, noise and land pollution. The chapter outlines the main problems related to industry, inadequate service delivery and the current status of how these problems are dealt with. Sustainable resource consumption and predictions are not addressed as these are not currently a priority focus area in Greater Johannesburg.

OVERVIEW ON CURRENT STATUS OF POLLUTION WITHIN GREATER JOHANNESBURG
A composite analysis of pollution in Greater Johannesburg has been undertaken, which comprises of  water, air, land and noise pollution levels. Pollutants can be grouped according to the main ecosystem which they affect. One pollutant often affects more than one ecosystem (Enviro Facts, 1999a).

• The worst polluted areas are found in a band from east to west through the Johannesburg Central Business District (CBD), where all types of pollution are found. High water pollution levels are due to bad pH and copper levels in industrial effluent from areas such as Industria West, Amalgam, Selby and Droste, continuing eastwards to Benrose, Denver and Heriotdale. High bacterial content is also found in the water due to blocked sewers, waste from informal settlements and the northern areas of the Inner City, which is more densely populated.  Industries, bus commuter ways

  and the concentration of slow moving vehicles in the city, cause high air pollution levels.

  Dust pollution from mine dumps to the south of the city centre also contributes to the high levels of air pollution.

  There are also high levels of land pollution which are caused by the concentration of commercial activities in the CBD,
  	as well as the illegal dumping of solid waste. Littering by informal traders and businesses , unmaintained sewage pipes, informal settlements, and the large amounts of
  refuse due to overcrowding in parts of the CBD, also causes land pollution.

  Lastly, noise pollution levels are serious in and around the CBD because of the densely developed built form, and from the high level of activity, hustle and bustle of all forms of vehicular traffic, industries and activities such as nightclubs.

• High levels of pollution are also found to the south of the CBD from Southgate to Elandspark in the east, mainly due to water, air and noise pollution. The water of the Klip River is badly polluted due to runoff from the mining areas and from large industrial areas like Aeroton, Booysens, City Deep and Electron.

  Air pollution originates from industries, the belt of mining land,vehicle emissions and from the burning of coal and other fossil fuels, like petroleum in the area. The industrial area, mining activities and small distances between roads results in major noise pollution.

• Pollution levels are high around Soweto. To the southeast, bacterial and industrial effluent levels in the water are high due to the Devland industrial area, as well as the sewage works and informal settlements located in the area. Very high levels of air pollution are caused by excessive amounts of coal-burning taking place in and around the Greater Soweto area.

  The presence of industrial activity, the Goudkoppies Landfill site, the Orlando Power station (now being de-commissioned), untarred roads, refuse burning
  and the poverty of the area, adds to air pollution.

  Littering, unmanaged waste and sewage, and irregular services, all cause land pollution in informal settlements in Soweto, while landfill sites are also areas of land pollution. Noise pollution mainly emanates from the Devland industrial area, Orlando Power station and vehicles (mainly busses and taxis) entering and leaving Soweto on a daily basis.

The worst pollution is concentrated to the southeast of Soweto where the Goudkoppies Landfill site, Devland industrial area, major roads, and the Freedom Park and Goldev settlements are located. High pollution levels are around the N12 in the Nancefield vicinity, as well as in the Mofolo, Diepkloof/Orlando, Dhlamini and Protea areas in Soweto.

• High pollution levels are found in the east of Lenasia, where excessive coal burning in the Thembelihle settlement is a major cause of air pollution. Inadequate refuse removal and illegal dumping leads to land pollution in the area, while noise mainly comes from vehicles travelling to and from Johannesburg and surroundings, as well as from light industries in the vicinity.
• Air pollution in Ennerdale is largely influenced by excessive coal burning in informal settlements to the southeast, vehicle emissions from the N1 and major roads, and dust from gravel roads. Illegal dumping and irregular refuse removal causes land pollution, while noise pollution comes mainly from major roads, taxi and bus routes, and some light industries.
• Poortjie, southwest of Ennerdale, and the Orange Farm area, are affected by  moderate to excessive coal burning and dust from gravel roads and open/ agricultural land, which causes air pollution. Orange Farm and Poortjie are plagued by vehicle emissions, littering, illegal dumping and irregular refuse removal, with high noise and land pollution levels along major and national roads.
• To the south of Roodepoort pollution levels are high in the Fleurhof area. High levels of water pollution are found due to mining activities, the Lea Glen industrial area and a nickel/chrome refinery in the area. Sources of air pollution include the industrial area, mining dust, and moderate to excessive coal burning and vehicular activity. Land pollution mainly includes industrial and residential waste, while noise comes mainly from industries and vehicles on main roads.
• West of Roodepoort, the Roodepoort West industrial area, CBD activities and excessive coal burning in the Davidsonville settlement, causes air pollution. Land pollution is mainly due to a lack of refuse removal and sewage services, together with high levels of litter and refuse in the Davidsonville settlement; mining dust; and CBD activities such as commerce and transportation. Vehicle noise is high due to the proximity to roads and combines with noise from industries and mining activities.
• North of the Johannesburg CBD, polluted areas are found north and south of Randburg, and to the south of Sandton. This consists mainly of:
  - air pollution (from vehicle emissions, industries and commercial activities     in the decentralised CBD’s);
  - water pollution (from urban/ residential runoff, blocked sewers and              industries);
  - land pollution (from commercial activities in the CBDs) and
  - noise pollution (from proximity to roads and large amount of vehicle            activity).
• These forms of pollution overlap in these areas to produce major environmental problems.
• Pollution levels are high to the northeast of Sandton, and in Alexandra. Industrial activities in the Wynberg / Kew area, as well as moderate to excessive coal burning taking place in Alexandra are the main causes of air pollution. Water quality levels are low due to industrial effluent and inadequate sanitation services in the densely populated informal settlements. Settlements around Alexandra show high levels of litter, as well as inadequate sanitation, sewage and solid waste services, which all combine to cause land pollution. Noise pollution emanates mainly from car, bus and taxi movement, although the Wynberg / Kew industrial area also plays a role.
• Lastly, in the far northern areas of Greater Johannesburg, pollution levels are high at the Diepsloot and Zevenfontein settlements. Smoke from excessive coal burning causes air pollution, whilst the lack of adequate refuse removal, sewer systems and service provision leads to land pollution. Noise levels are high along the N14 national road and other major roads, and water pollution in the area originates from the lack of environmental education and people’s ignorance.
• The causes of air, water, land and noise pollution is consistent throughout the Greater Johannesburg Area. These trends should be addressed through environmental education and planning responces.

REFERENCES

Enviro Facts 1999a: Pollution. http://www.botany.uwc.ac.za/EnvFacts/facts/pollution2.htm

Miller, G.T. 1992: Living in the Environment. Wadsworth: California.