Exxon Valdez Oil Spill and et Al. Essay

Submitted By Shawn-Stoneberg
Words: 1436
Pages: 6
Open Document
The Biodegrability of Petroleum Hydrocarbons and Their Effects on the Environment
27/03/14
Word Count: 1413
Introduction
Many tons of petroleum hydrocarbons have been spilled and have contaminated the sediments of coastal and inland regions. The effects of these hydrocarbons in the soil can be devastating to the vegetation and the wildlife. The petroleum fuels do not decompose, and remain saturated in the soil for many years, and in many cases indefinitely, preserving traces of the fuel in the sedimentary rock record. Reddy CM, et al., (2002), found that the hydrocarbons in the No.2 fuel, dumped by the barge Florida in 1969, were still present in the marsh sediments of the bay thirty years after the initial contamination. Only the n- alkanes were completely degraded, contrary to previous studies that stated that other branched alkanes had degraded as well. Their studies concluded that at this site in Falmouth the hydrocarbons would persist indefinitely, and would be preserved in the rock record. When heavier petroleum hydrocarbons are spilled and absorbed into the soil they will not completely dissolve unless under certain conditions, and will have a long-term effect on the surrounding environment.

Biodegrability of Oil
Venosa AD, et al., (2010), researched the biodegrability of the 19 year lingering oil on the beaches of Prince William Sound from the Exxon Valdez oil spill in 1989. They found that although a substantial amount of weathering had occurred, high concentrations of hydrocarbons remained in the sediment, and could still pose a threat to organisms that encountered it. For the biodegradation of oil to occur there must be a competent population of oil degrading bacteria, and nutrients present. Unavailability of these factors may have been a reason why the oil on the beaches lingered for such a long period of time. A gas chromatogram of hydrocarbons extracted from the sediments at West Falmouth one year after the spill showed a loss of oil compounds due to evaporation, water washing, and the loss of n-alkanes due to microbial degradation (Reddy CM, et al., 2002). Venosa AD, et al., (2010), calculated that approximately 0.6-1.3 g N/kg sediment and 44-99 g O2/kg sediment would be required to completely biodegrade the oil. Seawater contains only 0.2 mg N/L and about 8-9 mg O2/L. Thus about 3 000- 11 000 L of water must come into contact with each kilogram of contaminated sediment in order to provide enough nutrients and oxygen for complete biodegradation of the oil to occur. Hydrocarbon biodegradation occurs at the hydrocarbon- water interface. Thus the surface area to volume ratio of the oil can impact the biodegradation rate (Venosa AD, et al., 2010). Many physical boundaries can affect this ratio, such as rock beds with very low permeability and porosity. An intertidal zone of course- grained gravel shores and armoring from boulders and cobbles can inhibit disturbance by waves, thus reducing the hydrocarbon- water interface (Peterson CH, et al., 2003). It is physically impossible for the oil to completely dissolve out of the soil before any long term problems occur. Not all fuels are this difficult to erode, lighter crudes contain simpler, lighter hydrocarbons than heavy crude and are therefore more easily biodegraded.

Effect of Lingering Hydrocarbons on Environment
Oil that is spilled into the ocean and washed on the shore can have a serious impact on the surrounding environment. The oil that is washed into rivers impacts populations of fish, and the oil that is washed ashore and absorbed into the soil affect vegetation and animals. Some oil spilled during the Exxon Valdez spill was trapped under mussel beds providing a route of entry into many food chains. The subsurface grains of stream banks harbored the oil, exposing and killing salmon embryos (Peterson CH, et al., 2003). Chronic exposure to the oil persisting in the sediments were evident in fish, sea otters, and seaducks, all who rely on the sediments for
Show More

Related Documents: Exxon Valdez Oil Spill and et Al. Essay

How Biological Factors Influence An Individual's Behaviour Essay

Explain how biological factors might influence an individual’s behavior when it comes to the sleep cycle identifying the biological rhythm involved. Give an example of a disruption to the biological rhymes and explain how this can affect behavior. This essay will begin by explaining biological factors which may influence an individual’s behaviour when it comes to the sleep cycle. We will identify the biological rhythms that are involved in the process of sleep, we will do this by looking at the…

Words 1594 - Pages 7

e.coli contamination in the harbour Essay

uses 52% of all oil consumptions in the world (Rodrigue, 2010). In 2008, Canada was listed among the top ten oil-consuming nations worldwide along with the U.S., which alone consumed around 208 million barrels of oil per day (Stanley, 2008). The soaring prices of gasoline have led to the possible solution of oil drilling in the Arctic Circle to alleviate the pain at gas pumps. As Arctic ice shelves melt and become more penetrable due to global warming, many nations are considering oil-drilling initiatives…

Words 2268 - Pages 10

Essay on Ranger: Prefectures of Japan and Japan

violently with strong reducing agents and can react with strong oxidizing agents and with air under extreme temperature), and radioactive materials from the Fukushima Daiichi nuclear power plant to oil products release when automobiles were inundated by the tsunami. The earthquake also sparked many gas and oil fires in the interior of the country which contributed to the air pollution and particulates that are in the air. A lot of the hazards that are involved with the clean-up and hazardous to the…

Words 8813 - Pages 36