Exxon Valdez


Exxon Valdez Eyeglasses  [c.389]

Chemical transformations of oil are evoked through photochemical oxidation and microbial biodegradation. Not only is the latter more important in nature, blit strategies can be adopted to stimulate biological degradation, consequently termed bioremediation. All marine environments contain microorganisms capable of degrading crude oil. Furthermore, most of the molecules in crude oils are susceptible to microbial consumption. Oil contains little nitrogen or phosphorus, and as a result, microbial degradation of oil tends to be nutrient limited. Bioremediation often depends upon on the controlled and gradual delivery of these nutrients, while taking care to limit the concurrent stimulation of phytoplankton activity. Approaches that have been adopted are the utilization of slow-release fertilizers, oleophilic nutrients, and a urea-foam polymer fertilizer incorporating oil-degrading bacteria. Bioremediation techniques were applied successfully in the cleanup of Prince William Sound and the Gulf of Alaska following the Exxon Valdez accident. Alternative bioremediation procedures relying on the addition of exogenous bacteria have still to be proved. Similarly, successful bioremediation of floating oil spills has yet to be demonstrated.  [c.84]

Firstly, given that nutrient availability often limits microbial activity, fertilization with nitrogen and phosphorus has been used. To prevent rapid dilution and to maintain a sufficient concentration of nutrients to support the maximal oil biodegradation rates, they generally are incorporated into oleophilic nutrient formulations or microemulsions, which are retained in interfacial regions (e.g. air-sea interface or on the surfaces of sediments in beaches). Its efficacy during actual response operations has been demonstrated on cobble beaches contaminated by the Exxon Valdez spill in Alaska. Secondly, diverse means to oxygenate sedimentary environments have been attempted because anoxic conditions dramatically limit microbial oil degradation rates. Deeper penetration of oxygen and nutrient supplements can be achieved with tilling and raking. Alternatively, chemical oxidants, such as hydrogen, calcium, and magnesium peroxides, can alleviate oxygen deficiency within sediments. Transplantation may aerate the rhizosphere and serve as a means to stimulate aerobic oil biodegradation. The introduced plants also may take up oil and release exudates and enzymes that further stimulate microbial activity. This technique, known as phytoremediation, has potential application in delicate and sensitive salt marsh environments that are the most difficult to clean. Finally, methods to increase the surface area of the oil-water interface have been applied, this being where microbial oil degradation principally occurs. Thus, chemical dispersants, surface agents such as powdered peat, and fertilizers supplemented with biosurfactants have all been used as bioremediation agents.  [c.91]

In any industrial facility, from offices to factories and laboratories, spills happen and create a variety of risks to workers. Inside a plant, spills result in chemicals on the floor, in the air, or on the workers themselves. When releases occur outside the plant (e.g., chemical releases from tank cars or trucks, the spread of noxious fumes from an internal spill), the potential for harm extends far beyond the facility, particularly with major catastrophes such as the Bhopal chemical release, the Exxon Valdez oil spill. New York s Love Canal, and dioxin-contaminated Times Beach in Missouri, have led several federal departments and agencies to enact protective regulations. These protections are aimed at protecting a much broader range of people, property, and the environment than most regulations administered by OSHA.  [c.1077]

Although the pipeline from the North Slope to the port of Valdez was the route chosen and completed in 1977, the scientific community preferred the trans-Alaska-Canada route its use would have prevented the Exxon Valdez ianker accident of 1989.  [c.480]

Some environmentalists anticipated a major accident like that of the Exxon Valdez. When plaiiiiing for the Trans-Alaska Pipeline took place during the energy crisis of the early 1970s, it was controversial because of the conflicts of balancing the needs of oil  [c.480]

Since the 1970s, the petroleum industry has been increasingly affected hy the regulatory push at the international as well as federal and state levels. Oil spills, such as the one involving the Exxon Valdez in Alaska in the 1980s, put the regulatory spotlight on the environmental dangers inherent in moving oil hy marine tanker. Since the 1970s, The International Maritime Organization (IMO), in conjunction with the U.S. Department of Transportation (DoT) and the U.S. Environmental Protection Agency (EPA), has stepped up its efforts to implement measures to increase protection of the environment on U.S. and international waters.  [c.949]

Exxon Valdez runs aground off the Alaska coast.  [c.1250]


See pages that mention the term Exxon Valdez : [c.83]    [c.479]    [c.52]   
13 Chemistry in the Marine Environment (2000) -- [ c.83 , c.91 ]

Macmillan encyclopedia of energy Volumes 1,2,3 (2001) -- [ c.949 ]