Point and non-point pollution sources

Pollutants are usually divided into two types; namely point and non-point sources according to their way of application to the water bodies. Point sources are pollutants that enter to the water bodies at a certain point or location. Examples of point pollutants are discharges from industries to a river or lake by a pipe, canal or a stream. Non-point or diffused pollutants are applied to a river or lake through a number of points or locations. Examples of non-point pollutants are drainage water that comes from agricultural areas and enter to a river or a lake through many points that may extend for a few meters or kilometers.  
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Are you aware of the impact of oil pollution to the coastal and marine ecosystem?
Oil spills on seas, oil remnants leaking from ships and oil spilling after accidents imply severe damages to  the ecosystem.
Effects of oil pollution on fisheries are observed particularly in reproduction and migration seasons, and this is aggravated in narrow areas and straits with little water circulation like Bosporus in Istanbul, which is the migratory route between the Mediterranean and the Black Sea. It is widely known that spawns and larvae of aquatic lives are more sensitive to oil pollution; the reason for this is that many fish, crustaceans and arthropods spend their first stage on surface which is largely affected by the oil spillage. Besides, the impact on pollution on commercial fish species might result on its unfeasibility for consumption.  
Sea birds are usually the species affected the most, resulting very often on lost of lives  (Güven and Öztürk, 2005).