Marine pollution can be a catastrophic event for coastal communities and an environmental disaster for marine wildlife. These effects can be demonstrated by the effect of the grounding of the Exxon Valdez in the natural wilderness of Prince William Sound and the sinking of the Prestige off the coast of Spain.
In 1989 the Exxon Valdez, a new single hulled oil tanker, ran aground in the pristine waters of Prince William Sound in Alaska. The ship spilled up to 10 million gallons of fuel oil resulting in the death of thousands of animals including up to 250,000 seabirds, 2,800 sea otters, 300 harbour seals, 250 bald eagles, and 22 orcas, as well as the destruction of billions of salmon and herring eggs.
Due to a thorough cleanup, little visual evidence of the event remains in areas frequented by humans, however as of early 2007 more than 26,000 gallons of oil are estimated to remain in the sandy soil of the contaminated shoreline. Environmentalists expect it may take up to 30 years for the environment to fully recover.
The Prestige, an aging single hull oil tanker carrying 77,000 tonne of heavy fuel oil, suffered a hull failure in heavy seas off the coats of Spain in 2002. The Captain requested help and a port of refuge from Spain and was refused. French, Spanish and Portuguese authorities forced the ship out to sea, where it later broke up and sank about 120NM off the coast of Spain.
The effect of the subsequent oil spill cost over 100 million Euro in clean up costs and loss of revenue from fishing and tourism. The wreck continued to leak oil at around 125 tonne per day until 2004, when the remaining oil was removed.
The main causes of pollution are a result of:
Most pollution events, however, are more mundane and occur in the ordinary course of a ships life such as operational or accidental discharges.
MARPOL, which sets out the operating parameters for ships, is a major force in combating marine pollution.
For further information also visit the AMSA website section on Pollution and protection of the environment
NSW Maritime also has a very good section on pollution and environment protection