The poor disposal of waste in parts of the Durban Metropolitan Area (DMA) has had significant negative impacts on many aspects of the natural environment as well as negatively impacting on the health of some communities.

Soil and Freshwater Pollution
Soil and freshwater resources in the DMA are vulnerable to pollution from landfills, the illegal dumping of waste and effluent from waste water treatment works. Soil and groundwater can become polluted by landfill sites if leachate (the liquid formed during decomposition of disposed waste material) moves through the surrounding soil and enters the groundwater. In particular, the leaching of heavy metals and hazardous chemicals can be dangerous to plants, animals and people. Recently designed landfills are engineered with complex liner systems to collect the leachate which is then stored in a leachate dam for further treatment and ultimate disposal to sewer. Older landfills, and old cells of existing landfills in the DMA have no or inadequate liners in place, as this was not previously required by law.

Illegal dumping of waste on land and into rivers throughout the DMA contributes to soil and water pollution. It is also impacting on biodiversity and the recreational value of open space areas.

Several sewage works, which service the DMA, discharge their final return flow directly into the main channel of the nearest river. Within the Durban Metropolitan Area, direct discharges into the river channel occurs in the Tongaat, Umdloti, Ohlanga, Umgeni, Umbilo, Umhlatuzana, Umlaas, Isipingo, Mbokodweni and Little Amanzimtoti rivers. This has resulted in instances of bacterial contamination and eutrophication of river systems. Eutrophication is manifest as abundant growths of Eichhornia crassipes (water hyacinth) in the Umdloti, Ohlanga, Umgeni, and Isipingo rivers and of Pistia stratiotes (water lettuce) in the Amanzimtoti and Little Amanzimtoti rivers.

Air Pollution
The disposal of waste products to the air has resulted in air quality problems in areas such as the Durban South Basin. Landfill sites have the potential if poorly managed to contribute to air pollution when hazardous substances such as benzene, trichloroethylene, tetrachloroethylene, methane and naphthalene decompose. The decomposition creates volatile gases, and if they become concentrated in pockets, explosions can occur if a spark is introduced. At the Bisasar Road and Bulbul Drive Landfill Sites this problem has been mitigated through landfill gas recovery. Investigations are being undertaken to use this gas an a source of energy.

Marine Pollution
Seventeen point sources (marine pipelines and waste water works) discharge effluent into the sea in the Durban Metropolitan Area. Some of these are run by private companies such as SA Tioxide and AECI who manage deepwater pipelines. Sappi Saiccor located just south of the DMA also has a marine pipeline discharge. Two of the larger wastewater treatment works in Durban (Central Sewage Works and Southern Sewage Works) carry out marine disposal of waste via deepwater pipelines. The disposal of liquid waste to sea has, in some cases, resulted in the discolouration of water and localised pollution of marine areas. In general, though, Durban's fast moving marine current disperses waste material quickly resulting in minimal pollution.

Urban litter results in marine pollution when discarded waste is transported via the storm water drain system into the coastal marine environment. The marine area most heavily polluted by litter is the southern Metro region around the Umlaas and Reunion canals. The Harbour is also severely impacted on as stormwater drains from the Central Business District discharge directly into the harbour, making it unsightly at times and posing a potential health hazard.

Odours
Landfill gas causes an unpleasant smell in poorly managed landfills. Depending on the local topography and climatic conditions, odours may spread over a wide area. This impacts on the quality of life of communities as well as the market value of the surrounding land. Complaints about bad smells are particularly common during the wet summer season when the landfill sites are kept moist. This together with high temperatures facilitates the decomposition of waste and production of odours. Landfill waste is usually covered with material such as soil and rubble at the end of each day to reduce odour problems. At some landfill sites e.g. Bisasar Road, deodorising chemicals are released if the wind direction moves towards residential areas.

Dust
Dust becomes a problem at landfill sites due to the movement of heavy vehicles transporting and compacting rubbish. When sites are cleared of vegetation prior to engineering works, larger areas are left exposed and this provides a source of dust in windy weather. This problem has partially been overcome by the tarring and wetting of roads and other exposed areas.