 Water pollution can come from a number of different sources. If the pollution comes from a single source, such as an oil spill, it is called point-source pollution.  If the pollution comes from many sources, it is called nonpoint-source pollution.  Sometimes the pollution may affect the environment hundreds of miles away from the source, such as nuclear waste, this is called transboundary pollution.

 Surface waters are the natural water resources of the Earth. They are found on the exterior of the Earth’s crust and include:  Oceans  Rivers  Lakes * These waters can become polluted in a number of ways, and this is called surface water pollution.

* Dissolved oxygen levels depend on temperature, pond depth, productivity and fertility, and water movement.

 is where by water is polluted by Microorganisms which are microscopic creatures such as:  bacteria  viruses  protozoa.

 The suspended particles eventually settle and cause thick silt at the bottom.  This is harmful to marine life that lives on the floor of rivers or lakes.

 sewage often result in infectious diseases that infect life in water.  water pollution is a major problem in the developing world, with diseases such:  as cholera and  typhoid fever  cause of infant mortality.

 Small children and older adults are most likely to get sick from polluted water. These are the Symptoms:  Fever  Worms  Diarrhea  Tiredness  Stomach cramps  Sudden weight loss

 Sulphate particles from acid rain can cause harm the health of marine life in the rivers and lakes it contaminates, and can result in mortality.

 Industrial waste often contains many toxic compounds that damage the health of water animals and those who eat them.  Some of the poison in industrial waste can cause:  immune suppression  reproductive failure  acute poisoning.

 Oil gets into the water not only from spills but also through land based sources such as cars and industry.  Marine animals get suffocated by the thick oil and therefore die.

* the increase in the flow of nutrients and organic substances into water system is caused by:  urban runoff  Agricultural runoff  sewage discharges  eroded stream banks  leaking septic systems

 Algae cloud the water and block sunlight, causing underwater grasses to die.  these grasses provide food and shelter for water creatures.  When the algae die and decompose, oxygen is used up.  Dissolved oxygen in the water is important to most organisms living in the water

 Save water by turning off the tap when running water is not necessary. This helps prevent water shortages and reduces the amount of contaminated water that needs treatment.  Be careful about what you throw down your sink or toilet. Don’t throw paints, oils or other forms of litter down the drain.  Use environmentally household products, such as washing powder, household cleaning agents and toiletries.  By having more plants in your garden you are preventing fertilizer, pesticides and contaminated water from running off into nearby water sources.  Don’t throw litter into rivers, lakes or oceans. Help clean up any litter you see on beaches or in rivers and lakes, make sure it is safe to collect the litter and put it in a nearby dustbin