Water Quality

Water pollution is a worldwide problem. Almost anything can end up in Earth's water and pollute it. There are point sources (pollutants that enter the water from one point) and non-point sources (pollution that enters a water body from many places, primarily from runoff).

Agriculture is one example of non-point source pollution. Huge amounts of chemicals and fertilizers are applied to farm fields, which can run off into nearby streams or lakes, or filter through to the groundwater. Dissolved fertilizer causes too much growth of water plants and algae. This can lead to dead zones in the water where nothing else can live (because the plants are using all of the oxygen). Waste from livestock can also pollute water with bacteria. 

Municipal waste, or community waste, comes from households and businesses and can contaminate water supplies. Examples include lawn fertilizers and chemicals washing into sewers and drains; leaking underground septic tanks; municipal sewage waste-water treatment plants dumping treated waste into water. The treated water may still contain bacteria or chemicals used in the treatment process. 

Point source pollution from factories can also contain harmful chemicals or oil. Thermal pollution is often caused by power plants and factories. This is a type of pollution that raises the temperature of water. It can kill fish and other aquatic life because warm water cannot hold as much oxygen as cooler water. 

Source: USOE OER Resources. Retrieved from http://www.slcschools.org/departments/curriculum/science/documents/4-Earth-Science.pdf on August 31, 2013. 

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Last modified: Monday, 22 February 2016, 11:05 AM