Marine Pollution is defined as, " the discharge of waste substances into the sea resulting in harm to living resources, Hazards to human health, hindrance to fishery and impairment of quality for use of sea water."
SOURCES (OR) CAUSES OF MARINE POLLUTION :
1. Dumping the wastes.
The most serious issue is dumping of untreated wastes and sewage into oceans by the coastal towns and cities and industrial units. All That what is carried by rivers ultimately ends up in the seas. On their way to sea, rivers receive huge amounts of sewage, garbage, agricultural discharge, pesticides, including, heavy metals. These all are added to sea. Huge quantity of plastic is being dumped in sea.
2. Oil Pollution of Marine Water :
The great damage to water is imposed by petroleum and its products.
Heavy petroleum products precipitate to the bottom or are adsorbed on rock, stone, and sand banks to inhibit the life of the hydrobionts. One drop of petroleum spreads over a great area to isolate the water from contact with atmospheric oxygen.
Effects of Marine Pollution :
i) Presence of heavy metals and organic pollutants cause more damage in birds as thinning of eggshell and tissue damage of an egg.
ii) Oil Pollution cause damage to marine fauna and flora including algae, fish, birds, invertebrates. About 50,000 to 2,50,000 birds are killed every year by oil.
iii) Oil spilling in sea water causes abnormally low body temperature in birds resulting in hypothermia. Nearly 150 rare species of bald eagles also became victims when they ingested oil during Exxon Valdez accident.
iv) Oil films are able to retard significantly the rate of oxygen uptake by water.
v) The continuous oil films inhibit photosynthesis and formation of oxygen. This inhibits the growth of plankton, which is the main source of the hydrobionts inhabiting the water body.
vi) Hydrocarbons and benzopyrene accumulate in food chain and consumption of fish by man may cause cancer. Detergents used to clean up the spill are also harmful to marine life.
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