Ocena brak


Autor /Beatryks Dodano /11.11.2011

When a tanker collides with a rock or another ship, an oil leak occurs. The oil leaking onto the surface of water forms a thin layer and, if not treated, is brought with the waves to the shore.

Oil glues feathers of a bird and makes it unable to fly away from the oil leak. If a bird is caught it has to be carefully washed and dried which involves hard work of a lot of people.

Oil also prevents oxygen from the air to dissolve in water and a lot of other sea animals suffocate under the surface if an oil leak is not quickly removed.

An oil leak can be removed in three ways. Mechanically, that is by putting special floating hose around the leak and sucking it from the surface, which is done by very expensive specialised ships. Chemically, that is  by putting a detergent directly on a leak, which allowsthe oil to be dissolved in water and sink at the sea bed. Biologically, by use of special oil-eating bacteria which change oil into harmless substances such as water and carbon dioxide.

If an oil leak reaches the shore and pollutes the sand, the contaminated soil has to be first collected mechanically by lots of people and special equipment.

Only then the remaining pollution can be removed biologically.

The chemical method is the cheapest and the fastest one but it leaves a layer of oil on the sea bed, killing sea life there. The mechanical and biological methods are expensive and may take many days before the leak disappears but leave little ecological damage.

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