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Causes of ocean pollution

Updated: Feb 8

Date of publication: 13/07/2023

The most common causes of ocean pollution mainly come from land - sewage, oil spills, septic tanks, and industry. Marine pollution affects marine ecosystems, wildlife health, and human well-being. Furthermore, the extinction of animal species from the ocean affects the food chain of the entire environment, and pollution can cause the destruction of ecosystems.

ocean pollution

Oil spills

An oil spill can be defined as the unintentional release of oil into the environment as a result of human activity. Much of the ocean pollution from oil comes from tankers washing their holds at sea to save time in port. So, in these cases, the person responsible for each vessel must follow the laws relating to oil discharges.

Oil spills account for about 12% of oil entering the ocean. The rest comes from the unloading and trips of oil tankers. An oil tanker spill is a big problem because it concentrates a large amount of oil in one place. Moreover, these spills can cause a very localized problem but can be catastrophic for all local marine life.

Also, a part of the problem is that oil cannot dissolve in water, so it forms a thick layer on the surface. This layer suffocates fish and remains in the feathers of seabirds, preventing them from flying. It even blocks the light necessary for the photosynthesis of aquatic plants. In addition, oil is very difficult to clean up, which means that it stays in place after a spill.

oil spill

Chemical contamination

Usually, this type of pollution is carried out by industries and farmers. Such pollution occurs when part of the waste from certain areas is discharged into the sea. There are many forms and cases of this type of pollution. An example of this is factories that discharge their waste into the sea because it is cheaper than removing it as prescribed by law. In addition to being harmful to the health of the sea, this type of pollution increases the temperature of the ocean. Therefore, many animals and plants die, because they cannot survive such temperatures.

The most common contaminants from industrial sources include asbestos, mercury, and sulfur. There are also other elements that are difficult to clean, are non-biodegradable, carcinogenic, and harmful to marine life by many other factors.

chemical contamination

Waste pollution

Atmospheric pollution is a major source of ocean pollution. This happens because objects on land are carried by wind over long distances and end up in the ocean. Also, this happens when people throw garbage directly into the sea. Therefore, these objects that reach the sea can be natural things such as dust, dirt, garbage, and debris.

Most waste, especially that made of plastic, is not biodegradable, so it remains in ocean currents for years without breaking down. Furthermore, animals can become entangled in plastic pieces or swallow them thinking they are food, but because they are toxic, the animals die. Garbage accumulation also causes other effects. Although the ocean can absorb carbon dioxide, these levels are rising due to pollution. This causes its absorption mechanisms, due to the increase in ocean temperature, to be unable to continue absorbing that element.


Liquid waste that comes from household chores, such as cooking, washing clothes, toileting, and showering, ends up in the oceans. Most communities treat, clean, and discharge this wastewater into the oceans. But even though they are treated, they never reach the level of pure water. In underdeveloped countries, the wastewater is not treated but is thrown directly into the oceans or water bodies. This is dangerous because it can contaminate the environment and water bodies, spreading many diseases to humans.


The causes of ocean pollution will always be present and unfortunately, it is not possible to eliminate them completely. So, it is possible to reduce the damage by some percentage. That’s why we should raise the awareness of the masses about the alarming state in which the oceans are.


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