Oil spills are a byproduct of human activity in which oil is leaked “from ships, shore facilities, pipelines and offshore platforms” (1). Despite popular belief, the largest contributors to oil spills are not tankers, ships that carry large amounts of oil, but rather automobiles, boats, industrial plants, and machinery. This oil eventually reaches the ocean where it harms marine ecosystems. The severity of oil spills, however, is influenced by many factors, including the type of spillage, the quantity of oil, and the effects of tidal waves (2).
Categories of Oil and Associated Severities
According to the U.S. Fish and Wildlife Service, oil spills can be classified into five categories: very light oils, light oils, medium oils, heavy oils and very heavy oils.
Very light oils, such as gasoline and jet fuel, are extremely toxic to marine organisms, but evaporate rapidly in water so cleaning spills of this type is unnecessary.
Light oils, such as diesel, leave a residue in water and have long–term consequences on ocean life. Although light oils have fewer toxins than very light oils, they are still damaging. Nevertheless, light oil spills can be effectively cleaned.
Medium oils, including crude oils like petroleum, do not evaporate quickly. As such, these oils can devastate marine communities residing in intertidal areas, or areas between high and low waters. Medium oils are especially threatening to birds and mammals as they can adhere to their feathers, hair, or fur. Cleaning up medium oils is most successful if done immediately following the spill.
Heavy oils, on the other hand, are less likely to evaporate in water and can be exceptionally detrimental to aquatic life. Heavy oils are known to injure birds and mammals that come in contact with the contaminated site. Decontaminating areas in which heavy oils have been spilt is also very challenging.
Very heavy oils, also known as Group V oils, are capable of hovering and diffusing into water, affecting animals like lobster, which subsist on ocean floors. While Group V oils are not as toxic as the lighter oils, finding and pinpointing these oils is a difficult task (3).
Detrimental Outcomes of Oil Spills
Because oil does not dissolve in water, it undergoes a “biological, physical and chemical process called weathering” (1). Weathering degrades oil through natural mechanisms produced by sunlight, tidal waves, water temperature, and bacteria. As a result, some oil spills have short-term consequences, persisting for only weeks. If oil contaminates shallow water, however, the results can be much more dire. In these cases, the oil mixes with mud and other substances and accumulates on the bottom. As a result, the oil can last for decades causing a number of problems for marine life that comes in contact with the contaminated materials.
In the British Petroleum (BP) oil spill of 2010, 4.9 million barrels of crude oil were spilt in the Gulf of Mexico (4). According to Time, thousands of dead invertebrates like starfish and coral were found. Unfortunately, these species play an essential role in the ecosystems to which they belong, thereby impacting many other marine populations. Similarly, many dolphin offspring were found dead along the Gulf Coast. Oyster beds were also devastated by the oil spill; in fact, it could take ten years for the population to reach its former size (4).
The 1989 Exxon Valdez oil spill was equally catastrophic. According to BBC News, the oil killed over 250,000 seabirds, 2,800 sea otters, 250 bald eagles, 300 harbor seals, and 22 killer whales, as well as countless herring and salmon (5).
In addition to killing many sea dwellers, oil spills can also impact the health of those that survive. Oil can modify invertebrate feeding habitats, disrupt their shell development, and cause slow suffocation. Bottom-dwelling invertebrates are especially at risk when oil accumulates at the shoreline (2). Many bottom-dwellers can survive oil contamination; however, they transmit these toxins to their predators, leading to increased concentration of the toxins in higher species. From oil spills, fish can experience impeded growth, respiratory and cardiac malfunction, and stunted larval development. As a result, survival rates for offspring are low.
Oil spills can similarly thwart plant development. They can also spur growth of certain algae populations. When oil directly contacts birds, it can get in their feathers, which impedes their abilities to fly. As a result, many birds drown while others die of hypothermia. If oil is ingested, kidney, liver and lung damage often results, usually followed by death. Other side effects include an inability to reproduce, abnormal behaviors, a debilitated immune system, and skin irritability (2).
Humans can also be affected by oil spills. In Ogoniland, Nigeria, for example, the people have dealt with nearly 50 years of oil production and water contamination. Many communities are faced with dangerous levels of carcinogens, cancer causing agents. In one such community, families are drinking water polluted with benzene, a type of carcinogen, at a concentration 900 times that considered to be safe. In other areas of Ogoniland, nearly eight centimeters of oil were found on top of the water. This horrific spill has so far killed tens of thousands of people, as well as livestock, and is predicted to take up to 30 years to reach its former clean state (7, 8). Altogether, it will cost approximately $1 billion to rebuild the area. The Shell Oil Company, which was responsible for the spill, has neglected the impact this spill has had on the Nigerians. They have, however, taken responsibility for the recent 2008 and 2009 oil spills.
There are many natural processes that degrade oil, but human efforts are often required to prevent long-term damage to the environment from oil spills. There are four main methods by which an oil spill can be cleaned up: booms, skimmers, chemicals, or burning. Booms are floating devices used to trap, collect, and absorb the oil surrounding it. Skimmers are boats that can remove the oil from the surface of the water. Certain chemicals can be used to break down the oil into its less dangerous components. Lastly burning the oil is also possible, but this is often avoided because it can produce unwanted air pollutants. The effectiveness of the cleanup depends on a number of factors, including tidal waves and weather conditions.
Although it is debated whether humans could live without oil, we are heavily dependent on it in the modern world. Nevertheless, companies must follow safe protocols. Unlike the Shell Oil Company’s failure to comply with this ordinance in Nigeria, companies must be prepared in advance to minimize the negative effects of oil spills on the environment. After the BP oil spill, BP proceeded to strengthen blowout preventers, install emergency systems, have pressure examinations, and increase personnel training. Although programs like these will not eliminate oil spills and leaks, they can at least help reduce the problem (10). The government also requires tankers to be double-hulled, which decreases the incidence of oil spills (11). Inspections and maintenance of the tanks can also be performed to reduce oil leaks.
If we continue to use oil in our everyday lives, we must make sure to use it efficiently. Individuals can make a significant difference with relatively simple efforts. The California Coastal Commission suggests learning how to correctly change and remove motor oil from vehicles, getting a vehicle tuned, taking public transportation, biking, and becoming an oil spill volunteer as possible ways to help improve marine life (11). The challenge now is taking the steps to ensure this is what happens.
1. J. W. Farrington, J. E. MacDowell, Mixing Oil and Water (2004). Available at http://www.whoi.edu/oceanus/viewArticle.do?id=2493 (22 October 2011).
2. Effects of Oil Spills on Wildlife and Habitat (2004). Available at http://alaska.fws.gov/media/unalaska/Oil%20Spill%20Fact%20Sheet.pdf (22 October 2011).
3. Oil and Nature (October 1998). Available at http://www.fws.gov/contaminants/Documents/OilAndNature.pdf (23 October 2011).
4. B. Walsh, The BP Oil Spill, Once Year Later: How Healthy is the Gulf Now? (2011). Available at http://www.time.com/time/health/article/0,8599,2066031,00.html (23 October 2011).
5. World: America’s Exxon Valdez: Ten Years on (1999). Available at
http://news.bbc.co.uk/2/hi/americas/298608.stm (22 October 2011).
6. Nigeria Ogoniland oil clean-up ‘could take 30 years’ (2011). Available at http://www.bbc.co.uk/news/world-africa-14398659 (04 November 2011).
7. C. Koettl, (S)Hell in the Niger Delta: Satellite Images Document Oil Spills (13 November 2011). Available at http://blog.amnestyusa.org/business/shell-in-the-niger-delta-satellite-images-document-oil-spills/ (18 November 2011).
8. R. Knox, How Will The Gulf Oil Spill Affect Human Health? (2010). Available at http://www.npr.org/templates/story/story.php?storyID=128008826 (18 November 2011).
9. Oil Spills (2011). Available at http://library.thinkquest.org/CR0215471/oil_spills.htm (25 November 2011).
10. BP Releases Report on Causes of Gulf of Mexico Tragedy (2010). Available at http://www.bp.com/genericarticle.do?categoryId=2012968&contentId=7064893 (26 November 2011).
11. Oil Spills (2011). Available at http://www.coastal.ca.gov/publiced/oilspills.html#government (26 November 2011).
12. K. Angelova, U.S. Beaches That The Oil Spill May Ruin Forever (2010). Available at http://www.businessinsider.com/gulf-oil-spill-june-3-2010-6?op=1 (29 November 2011).