Why do oil spills exist

Jump to navigation. Oil spills into rivers, bays, and the ocean most often are caused by accidents involving tankers, barges, pipelines, refineries, drilling rigs, and storage facilities. Oil floats on saltwater the ocean and usually floats on freshwater rivers and lakes.

Very heavy oil can sometimes sink in freshwater, but this happens very rarely. Oil usually spreads out rapidly across the water surface to form a thin layer that we call an oil slick. As the oil continues spreading, the layer becomes thinner and thinner, finally becoming a very thin layer called a sheen, which often looks like a rainbow. You may have seen sheens on roads or parking lots after a rain. Depending on the circumstances, oil spills can be very harmful to marine birds and mammals and also can harm fish and shellfish.

You may have seen dramatic pictures of oiled birds and sea otters that have been affected by oil spills. Oil destroys the insulating ability of fur-bearing mammals, such as sea otters, and the water-repelling abilities of a bird's feathers, thus exposing these creatures to the harsh elements. At the same time, an oil spill involving small but continuous releases such as those from leaking pipelines or road runoffs may have little visible effect they are naturally attenuated usually due to microbial degradation as well as due to many chemical-physical processes.

The type, amount of oil discharged and its location will dictate the oil spill cleanup efforts , which could involve deployment of adsorbent booms, controlled burning, bioremediation, emulsification using detergents for increased degradation. Even though numerous climate factors and natural disturbances can generate oil spills , the main causes of oil spill pollution are usually of anthropogenic origin.

The most commonly encountered anthropogenic sources are the following:. Accidental spills may occur in various circumstances, most often during the following activities:. According to the Minerals Management Service , offshore drilling in U. Most of the oil products in the United States are made out of crude oil — the rough, unprocessed form of oil.

Gasoline, heating oil, petroleum and diesel fuel are all made from crude oil. Depending on the stage of processing, any one of these oils can get spilled into the environment. If the spill happens during the extraction process, crude oil is leaked. However, if the spill occurs after the crude oil has been refined, diesel fuel or petroleum is leaked. If the spill happens when a tanker's fuel supply is punctured, gasoline — another refined crude oil product - would seep into the environment.

Gasoline and diesel fuel molecules are smaller than crude oil molecules. Because of this, gasoline and diesel spills evaporate more quickly. However, these oils are highly toxic to living things, and can kill organisms that breathe in their fumes or absorb these oils through their skin. Crude oil and other so-called heavy oils are dangerous in a different way. Although they are less toxic, they are thick and gluey and can smother living creatures.

By covering the feathers of birds or the fur of marine mammals, these oils prevent the animals from maintaining their normal body temperatures, leading to death from hypothermia. And these oils don't evaporate, so they can remain in the environment for much longer.

According to the U. Department of Energy , 1. A major oil spill could easily double that amount. Between and , the U. Coast Guard identified more than , oil spills in U. Department of the Interior Minerals Management Service. Approximately 1. The Persian Gulf oil spill of is so far the biggest oil spill in the world. As Iraqi troops retreated from Kuwait during the first Gulf War, they opened the valves of oil wells and pipelines, pouring up to 8 million barrels into the Gulf, though estimates on the exact amount of oil spilled vary.

This would put this spill at several times the size of the Exxon Valdez disaster. Tanker accidents have accounted for most of the world's largest oil spills. They are less frequent than other kinds of oil spills, such as pipeline breaks, but typically involve large volumes of spilled oil relative to other kinds of oil spills. Between and , tankers and barges were responsible for 45 percent of the volume of oil spilled in U. Department of the Interior Minerals Management Service report.

In that same period, pipelines were responsible for 16 percent of the volume of oil spilled in U. This includes both onshore and offshore pipelines, though onshore spills accounted for most of the pipeline spillage into U. Between and , U. Outer Continental Shelf OCS offshore facilities and pipelines accounted for only 2 percent of the volume of oil spilled in U. Analysts for the Oil Spill Intelligence Report have reported that spills in that size range have occurred in the waters of nations since But certain areas see more spills than others.