Definition, sources and causes Water POLLUTION Definition, sources and causes

The importance of clean water Water covers about 70 % of the Earth´s surface. Water is an important resource that is essential to life.

What is Water pollution? Contamination of water bodies: Lakes Rivers Seas Oceans Groundwater Occurs when pollutants for example particles, chemicals or substances make the water bodies direct or indirect contaminated.

Two sources of water pollution: Point source One localized and specific source Nonpoint source Many diffuse sources

Give A few Examples: Point sources: Nonpoint sources:

Atmospheric deposition Agriculture Sewage and wastewater Marine dumping Industrial waste Oil pollution Atmospheric deposition Mining THE CAUSES OF WATER POLLUTION

Agriculture Fertilizers that are used in the agriculture contain high levels of nutrients. Improper application of fertilizers can lead to nutrient overload, eutrophication.

Eutrophication Phytoplankton starts to grow and reproduce more rapidly The algae use oxygen Algal bloom Less oxygen for other marine organisms Will block sunlight from photosynthetic marine plants under the water surface Some algae even produce toxins, cause harmful for marine organisms.

Sewage and wastewater Households, industrials and agriculture produce wastewater.

Sewage and wastewater Sewage means the wastewater that often contains feces, urine and laundry waste. Sewage and wastewater needs to be treated in wastewater treatment plants. If the sewage is not treated it causes harmful viruses and bacteria into the water bodies and causing health problems.

Marine dumping The garbage that are dumped in the water bodies, for example: Paper Food waste Aluminum Rubber Glass Plastic It takes a long time for the garbage to decompose. For example: paper 6 week, aluminum 200 years. The garbage cause a lot of harm for birds and marine life.

Industrial waste Industries produce huge amount of waste that contains toxic chemicals and pollutants. Many industries do not have proper waste management system and drain. The waste leach out to the water bodies. Causes changes in pH, color of the water, temperature, minerals and salt. These changes are harmful for marine life.

Oil Pollution Causes by oil spills, routine shipping, run-off and dumping. Oil do not dissolve in water and therefore form a thick layer on the water surface. Oil stops marine plants receiving enough light for photosynthesis. It is also harmful and toxic for birds and marine life.

Atmospheric deposition Water pollution caused by air pollution.

Atmospheric deposition Air pollution: sulfur dioxide and nitrogen oxide, when they are mixed with water particles in the air they form a toxic substance. This falls as acid rain to the ground and leaks out into water bodies. The water bodies gets contaminated and this affects the marine life.

MINING The process of crushing the rock and extracting coal and other minerals from underground.

MINING Chemicals are used in the mining process and damaging compounds and metals are removed from the ground. Mining cause erosion, leaching of chemicals, damaging compounds and heavy metals. Causes also changes in pH, toxic environments to humans and marine life.

Group work Agriculture Sewage and wastewater Marine dumping What is done to prevent/ reduce the causes of water pollution? Agriculture Sewage and wastewater Marine dumping Industrial waste Oil pollution Atmospheric deposition Mining

references http://www.waterwise.co.za/site/water/environment/causes-of-water- pollution.html http://eschooltoday.com/pollution/water-pollution/what-is-water- pollution.html http://www.water-pollution.org.uk/