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A beach after an oil spill
An oil spill is the release of a liquid petroleum hydrocarbon into the environment due to human activity, and is a form of pollution. The term often refers to marine oil spills, where oil is released into the ocean or coastal waters. The oil may be a variety of materials, including crude oil, refined petroleum products (such as gasoline or diesel fuel) or by-products, ships' bunkers, oily refuse or oil mixed in waste. Spills take months or even years to clean up.
Oil is also released into the environment from natural geologic seeps on the sea floor. [1] Most human-made oil pollution comes from land-based activity, but public attention and regulation has tended to focus most sharply on seagoing oil tankers. [2]
[edit] Environmental effects
The oil penetrates and opens up the structure of the plumage of birds, reducing its insulating ability, and so making the birds more vulnerable to temperature fluctuations and much less buoyant in the water. It also impairs birds' flight abilities, making it difficult or impossible to forage and escape from predators. As they attempt to preen, birds typically ingest oil that coats their feathers, causing kidney damage, altered liver function, and digestive tract irritation. This and the limited foraging ability quickly causes dehydration and metabolic imbalances. Most birds affected by an oil spill die unless there is human intervention.[3][4]
Marine mammals exposed to oil spills are affected in similar ways as seabirds. Oil coats the fur of Sea otters and seals, reducing its insulation abilities and leading to body temperature fluctuations and hypothermia. Ingestion of the oil causes dehydration and impaired digestion.
[edit] Largest oil spills
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Oil Spills of over 100,000 tonnes or 30 million US gallons, ordered by Tonnes[a]
Spill / Tanker Location Date *Tonnes of crude oil Reference
a One tonne of crude oil is roughly equal to 308 US gallons, or 7.33 barrels.
[edit] Estimating the volume of a spill
Other types of pollution
Inter-government treaties
Related topics
By observing the thickness of the film of oil and its appearance on the surface of the water, it is possible to estimate the quantity of oil spilled. If the surface area of the spill is also known, the total volume of the oil can be calculated.[11]
Film Thickness Quantity Spread
Appearance in mm gal/sq mi L/ha
[edit] Methods of cleaning
A sheen is usually dispersed (but not cleaned up) with detergents which makes oil settle to the bottom. Oils that are denser than water, such as Polychlorinated biphenyls (PCBs), can be more difficult to clean as they make the seabed toxic.
Clean-up efforts after Exxon Valdez oil spill.
Methods for cleaning up include:
Bioremediation: use of microorganisms [1] or biological agents [2] to break down or remove oil Controlled burning can effectively reduce the amount of oil in water, if done properly.[12] But it can only be done in low wind[citation needed], and can cause air pollution.[13] Dispersants act as detergents, clustering around oil globules and allowing them to be carried away in the water.[14] This improves the surface aesthetically, and mobilises the oil. Smaller oil droplets, scattered by currents, may cause less harm and may degrade more easily. But the dispersed oil droplets infiltrate into deeper water and can lethally contaminate coral. Recent research indicates that some dispersants are toxic to corals.[15] Watch and wait: in some cases, nautural attentuation of oil may be most appropriate, due to the invasive nature of facilitated methods of remediation, particularly in ecologically sensitive areas.[citation needed] Dredging: for oils dispersed with detergents and other oils denser than water. Skimming: Requires calm waters Solidifying[citation needed]
Equipment used includes[12]:
Booms: large floating barriers that round up oil and lift the oil off the water Skimmers: skim the oil Sorbents: large sponges that absorb oil Chemical and biological agents: helps to break down the oil Vacuums: remove oil from beaches and water surface Shovels and other road equipments: typically used to clean up oil on beaches
[edit] Prevention
Secondary containment - methods to prevent releases of oil or hydrocarbons into environment. Oil Spill Prevention Containment and Countermeasures (SPCC) program by the United States Environmental Protection Agency. Double hulling - build double hulls into vessels, which reduces the risk and severity of a spill in case of a collision or grounding. Existing single-hull vessels can also be rebuilt to have a double hull.
[edit] See also
[edit] References
^ http://seeps.geol.ucsb.edu/ ^ 16. Petroleum: Oil Spill ^ Dunnet, G., Crisp, D., Conan, G., Bourne, W. (1982) "Oil Pollution and Seabird Populations [and Discussion]" Philosophical Transactions of the Royal Society of London. B 297(1087): 413–427 ^ Untold Seabird Mortality due to Marine Oil Pollution, Elements Online Environmental Magazine. ^ George Draffan. "Major Oil Spills" (HTML) (in English). Endgame. Retrieved on 2007-07-29. ^ a b c d e "History" (HTML) (in English). The Mariner Group. ^ John S. Patton, Mark W. Rigler, Paul D. Boehm & David L. Fiest (1981-03-19). "Ixtoc 1 oil spill: flaking of surface mousse in the Gulf of Mexico" (HTML) (in English). NPG (Nature Publishing Group). Retrieved on 2007-07-29. ^ a b c d e f g h i j "Statistics" (HTML) (in English). ITOPF. Retrieved on 2007-07-29. ^ "Atlantic Empress/Aegean Captain" (HTML) (in English). Cedre (2006-04). Retrieved on 2007-07-29. ^ "Oil Spills and Disasters" (HTML) (in English). infoplease. infoplease. Retrieved on 2007-07-29. ^ Metcalf & Eddy. Wastewater Engineering, Treatment and Reuse. 4th ed. New York: McGraw-Hill, 2003. 98. ^ a b "Emergency Response: Responding to Oil Spills". Office of Response and Restoration. National Oceanic and Atmospheric Administration (2007-06-20). ^ Oil Spills ^ "Detergent and Oil Spills" (HTML) (in English). NEWTON BBS (2002-10-12). Retrieved on 2007-07-29. ^ Barry, Carolyn (2007). Slick Death: Oil-spill treatment kills coral, Science News vol. 172, p. 67.
[edit] Further reading
The World Almanac and Book of Facts, 2004 Oil Spill Case Histories 1967-1991, NOAA/Hazardous Materials and Response Division, Seattle WA, 1992 Nelson-Smith, Oil Pollution and Marine Ecology, Elek Scientific, London, 1972; Plenum, New York, 1973
[edit] External links
Oil Spill Response and East Asia Response Limited, World's largest oil spill preparedness and response service provider www.black-tides.com An educational website comprising texts, animations, diagrams, quizzes and video clips on oil spills www.cedre.fr Centre of Documentation, Research and Experimentation on Accidental Water Pollution International Petroleum Industry Environmental Conservation Association - online publications oil spill and environmental clean-up news International Tanker Owners Pollution Federation oil spills and pollution Newsweek's Black Tides Timeline How oil spill absorbent products Work What happened when we tested Oil absorbent pads, socks and mats Industrial pollution information from the Coastal Ocean Institute, Woods Hole Oceanographic Institution IncidentNews.gov - a NOAA site cataloguing major spills, April 14, 2005 A Google map of the major oil spills since 1960 A Google Maps Image of a minor oil spill in Libya Oil spill on Mississippi River after Hurricane Katrina 2000 Oil spill in Brazil Japan tanker spills 1.4M gallons of oil Ashland oil spill in Floreffe, Pennsylvania in 1988 - considered one of the most severe inland oil spills in U.S. history Oil spill prevention program
