There are many types of pollution that can harm the marine environment. However, the most common pollution of the sea comes from the land and not from ships. It has been estimated that 80% of the rubbish, chemicals and oil found in the sea actually comes from the land.
To learn more about land sourced pollution go to www.ausmepa.org.au/Stormwater
There are strict laws to prevent pollution of the sea by ships. Ship captains and crew who break the law can be given large fines, but accidents can happen.
The types of pollution that may originate from ships include oil, chemicals, garbage sewage, air pollution from the ship's engines and bunker fuel and the anti-fouling paint on a ship's hull. Marine pests in ship's ballast water or clinging to the ship's hull can also harm new environments. Even old ships that are to be broken up or scrapped on beaches in India, Bangladesh and China can cause pollution unless great care is taken.
Pollution caused by ships may not be as bad as some people think. Occasionally you may see on television a major oil spill occurring somewhere in the world.
This might be caused by an oil tanker suffering serious damage due to a collision with another ship, or because it ran aground or possibly the ship has been badly maintained.
A major spill of crude oil from an oil tanker may do less damage to the environment than a spill of bunker oil from a cargo ship, bulk carrier or a container ship. Bunker oil is more toxic than crude oil and is more difficult to clean up.
Thankfully, international regulations are very effective at preventing pollution of the sea by ships and these types of incidents are becoming much fewer. The regulations cover how ships must be correctly operated by the captain and crew. Ships must be designed and built with many safety requirements. A ship's captain and its crew are required to have the highest level of training and qualifications.
In Australia the international regulations are administered by the Australian Maritime Safety Authority; for more information go to www.amsa.gov.au
It is estimated that 95% of ship's crews do the right thing and comply with the pollution prevention laws and regulations.