Marine pollution refers to the contamination or presence of pollutants in oceans and seas. The word ‘marine’ comes from the Latin word for ‘sea’ and it is related to similar words, such as ‘mariner’. Ocean pollution is become ever more of a problem in the present day.

Marine pollution can be defined as anything that contaminates the sea. Common marine pollutants include chemicals, small plastic beads in exfoliants and also toxic bio-matter (such as sewage). But, noise – due to excessive traffic around the ocean – can also be defined as pollution if it disrupts marine life.

Pollution can vary depending on the context and the purpose for which seawater is being used. For example, normal seawater has some small particles of plants or sand in, and when the sea is considered as the habitat of marine animals, one would not think of these particles as pollutants – whereas one would definitely define toxic chemicals as pollutants. However if somebody wanted to use this brine for cooking in, they might see the sand and plants as polluting our cooking water.

Causes/Sources of Marine Pollution

1. Toxic chemicals in water.

Chemical runoff from industry can really endanger marine life. Industrial waste pumped into the sea, household cleaners poured down the sink, and even chemicals in the atmosphere (for instance due to the discharge of industrial wastes through factory chimneys) that dissolve into the sea can pollute our oceans significantly.

2. Oil spillages.

This is usually an accidental form of industrial dumping, whereby leaks in oil tankers cause vast quantities of oil to pour into the ocean. Accidental oil spills can devastate marine life.

3. Small particles.

The tiny plastic beads in exfoliating creams and other small particles that we pour down the drain without thinking wind up polluting the ocean.

4. Plastic, Litter, and human waste.

Plastic bags, aluminum cans, trash and other human waste constitute a major pollutant of the world’s oceans. A huge ‘island’ of trash roughly the size of Texas was recently found in the Pacific ocean for instance, demonstrating the vast scale of this problem.

5. Sewage.

Whether or not it is treated with toxic chemicals, sewage pollutes the clear, clean water of the oceans. This is another type of industrial dumping. Sometimes, sewage is not pumped directly into the sea but into rivers, and then the untreated water of rivers carries it into the sea.

6. The shipping industry.

Gases (which dissolve in the sea), chemicals and sewage from container ships are major pollutants.

7. Dissolved greenhouse gases.

Greenhouse gases from human fossil fuel consumption are making the sea more acidic.

Effects of Marine Pollution

1. Oxygen depletion.

Seawater is full of dissolved oxygen, however decomposing sewage and other biomatter in oceans can result in a condition known as ‘hypoxia’ or oxygen depletion. This makes it hard for oxygen loving marine life – plants, fish and animals – to survive in the oceans.

2. Higher acidity.

Toxic chemicals make our oceans more acidic. Again, this makes them poisonous to marine life and causes harm to fish and marine mammals as well as marine plants and corals.

3. Choking marine life.

Small pieces of plastic and other litter are increasingly being found in the stomach of fish, turtles and other marine animals. These pieces of trash choke marine animals and hamper their digestion, with an often fatal result.

4. Spoiling birds’ feathers.

Oil spills coat the feathers of marine birds and strip them of the natural oils that birds use to keep their feathers waterproof and to maintain their own body temperatures. As a result, marine birds can overheat or get too cold, and they find it hard to stay afloat as their feathers get soggy. They will also find it difficult to fly when their feathers are clogged with oil.

5. Blocking out the sunlight.

Pollutants such as oil or litter can block out the sunlight from sea plants which need sunlight for photosynthesis.

6. Dangers to human health.

Human swimmers and water sports lovers can become endangered by swimming in a polluted sea.

Steps taken to reduce Marine pollution:

The need for protection of this ecosystem has been acknowledged worldwide and UNCLOS 1982 prescribes the responsibility on the Coastal States in preserving and protecting the marine environment and associated resources.

The Maritime Zones of India Act 1976, enables the Government to take measures for protection of the marine environment.

The Coast Guard Act 1978 states that the preservation and protection of marine environment and control of marine pollution is the function of the Indian Coast Guard.

The comprehensively revised National Oil Spill Disaster Contingency Plan (NOSDCP) edition-2015 was released during the 20th NOSDCP meeting held at Goa on 09 Apr 2015, the revised plan reflect current international norms and best practices.

The Coastal States and Union Territories are responsible for shoreline clean-up, whenever the oil-spill reaches the shore, and threatens the shoreline.

Land based sources of pollution affecting the quality of the coastal waters have been identified. An action plan has been prepared requiring all industrial units to meet the stipulated standards within a time frame;

The coastal State Pollution Control Boards secure comconsent and monitoring mechanism;

Wherever applicable, the industries/municipalities have been directed to construct marine outfalls with a diffuser systems based upon the dilution capacity of the receiving body;

The Central Government has issued general instructions that no industry/ factory should be given a consent to establish within 500 meters from the shoreline.