Water Pollution and Your Health

This article is available in: English | Afrikaans | Sotho | Zulu

Water knows no boundaries and as it flows it links communities together through their many uses of this resource. The quality of a stream or river is often a good indication of the way of life within a community through which is flows. It is an indicator of the socio-economic conditions and environmental awareness and attitude of its users. Everything that happens in a catchment area is reflected in the quality of the water that flows through it, because the results of human activity and lifestyle ultimately end up in rivers, through runoff.

A river catchment consists of all the land, from mountain to seashore, that is drained by a single river and its streams.

Healthy streams, wetlands and rivers support a great variety of water life. Rain water and tumbling mountain streams contain high levels of oxygen. Much of the oxygen comes from the atmosphere through rain, tumbling water in fast-flowing streams and photosynthesis. Nutrient substances are washed into the system, providing important growth chemicals (eg. nitrates) and sources of food (eg. rotting plants). Water plants, in turn, photosynthesize and provide life-supporting oxygen and other food sources for water organisms that interact in a complex web of life.

All life in the water is dependent on the interaction within the river itself and in the surrounding catchment. These processes can either maintain a healthy ecosystem or disrupt ecological processes and degrade the water supply. Rivers and streams owe their existence to the nature of catchments and the relationship between rainfall and evaporation. Rivers are open systems where the exchange of material and energy within the environment occurs all the time. It is difficult to treat rivers as ecosystems because they are important pathways for the flow of energy and the circulation of nutrients across the boundaries of habitats.

An ecosystem is an area in which plants, animals, people and their surroundings interact through various relationships, eg. a pond.

Changes in water quality occur naturally along the length of a river; however, these changes may be significantly influenced by human activities. Industries, agriculture and urban settlements produced nutrient concentrates (sewage effluent and fertilisers) and toxic substances (poisonous pollutants) which can affect water quality.

What is polluted water?

Water quality is defined as water which is safe, drinkable and appealing to all life on earth. It should contain no chemical or radioactive substance that is harmful to the health of any life. It should be free of disease-causing organisms and stable in terms of corrosion or scaling. Polluted water is water that is not safe and not healthy for people and animals to drink or to wash in.

Polluted water is particularly dangerous to water plants and animals. Polluted water is also particularly dangerous to people who get their water directly from a river or dam. In South Africa the scarce fresh water is decreasing in quality because of an increase in pollution and the destruction of river catchments, caused by urbanisation, deforestation, damming of rivers, destruction of wetlands, industry, mining, agriculture, energy use, and accidental water pollution. As the human population increases, there is an increase in pollution and catchment destruction.