Friday, May 28, 2010

Gulf leak "worse than Exxon Valdez"

The amount of oil that has spilled from BP's blown-out Gulf of Mexico well has exceeded the 1989 Exxon Valdez disaster. And according to findings released Thursday from a US government panel, the oil could be flowing at a rate nearly four times BP's recent estimates [Reuters / AP].

The Exxon Valdez oil spill occurred in Prince William Sound, Alaska, on March 24, 1989, when the Exxon Valdez, an oil tanker bound for Long Beach, California, hit Prince William Sound's Bligh Reef and spilled an estimated minimum 10.8 million US gallons [40.9 million litres, or 250,000 barrels] of crude oil. It is considered to be one of the most devastating human-caused environmental disasters ever to occur in history. 

The latest disaster occurred when the an explosion struck the Deepwater Horizon drilling rig on April 20 this year. As a result of the explosion oil began to gush into the Gulf from the sea bed. Flow rate estimates vary widely, because some of the plume is apparently remaining well below the surface. Every day between 700 and 13,600 tonnes of oil pours into the Gulf unchecked and several efforts by BP to stem the flow have failed.

Estimates vary

BP's current estimate is that of over 5,000 barrels [210,000 US gallons; 790,000 litres] to as much as 100,000 barrels [4,200,000 US gallons; 16,000,000 litres] of crude oil is issuing into the Gulf each day. The exact spill flow rate is uncertain however. Estimates of the total amount of oil spilled are 450,000 to 930,000 barrels [19,000,000 - 39,000,000 US gallons; 72,000,000 - 148,000,000 litres]. Experts fear that due to factors such as petroleum toxicity and oxygen depletion, it will result in an environmental disaster, damaging the Gulf of Mexico fishing industry, the tourism industry, and the habitat of hundreds of bird species for years to come.

On Thursday BP continued in its effort to cap the leak 1,500 metres below sea level. After an 18-hour delay to assess its efforts and bring in more materials, BP resumed pumping heavy drilling mud into the blown-out well. Officials said it could be late Friday or the weekend before the company knows if the procedure known as a top kill has cut off the oil that has been flowing for five weeks.

Early Thursday, officials said the process was going well, but later in the day they announced pumping had been suspended 16 hours earlier. BP did not characterise the suspension as a setback. Eric Smith, associate director of the Tulane Energy Institute, said the move did not indicate the top kill operation had failed. Even if BP make progress, the log term repurcusions look dire. The company itself faces litigation and the damage to the environment could be long lasting.

Lasting damage

Almost 20 years after the Exxon Valdez oil spill, a team of scientists at the University of North Carolina found that the effects were lasting far longer than expected. The team estimates some shoreline Arctic habitats may take up to 30 years to recover. In fact only yesterday the Exxon oil disaster claimed another victim after Nuka, a gray-whiskered otter plucked from Prince William Sound soaked in oil in 1989, was put down. A visiting veterinarian determined the otter's condition had worsened rapidly. However Nuka was old for a sea otter, at least 21, one of only three otters still alive in captivity that had survived Alaska's Exxon Valdez spill. 

Nuka had struggled with immune-system problems, poor skin and fur, and seemed unable to groom herself properly, which meant she ate more than normal to avoid hypothermia. While no one could say what caused her problems, they were consistent with early exposure to petroleum. As such Nuka came to represent the kind of risks oil spills pose for marine life. Oil has been linked to heart defects in fish, reproduction problems in whales, and cancers and immune-system trouble in creatures throughout the food chain [Seattle Times].

Recent spills

This year there have been four major oil spills. On January 23, 2010 the oil tanker Eagle Otome collided with a barge in the Sabine-Neches Waterway at Port Arthur, Texas [Wiki]. There are disputes over the amount of leaked oil in that incident, varying from between 1,000 and 11,000 barrels [158,984 litres to 1,748,000 litres]. In April, shortly before BP grabbed the headlines, the Chinese tanker Sheng Neng 1 ran aground off the coast of Australia [Wiki]. As a result of the grounding, the fuel tanks of the vessel were punctured, allowing fuel oil to leak from the vessel. The oil slick measured at least 3 kilometres long causing damage to parts of Australia's Great Barrier Reef. The damage was considerable despite the relatively small, around 3 tonnes, of oil discharged. 

Great Barrier Reef Marine Park spokesman David Wachenfeld said that the Sheng Neng 1 created the largest grounding scar on the Great Barrier Reef known to date. The scar was roughly 3 kilometres long and 250 m wide. Some damaged areas have become completely devoid of marine life. There are concerns that there could be considerable long-term damage to the reef and it will be 10 to 20 years before the reef returns to the state it was in before the incident

Most recently a collision between the tanker, Bunga Kelana 3 carrying light crude, and bulk carrier, MV Waily; on Tuesday resulted in 2,500 tonnes [18,250 barrels / 2,800 litres] of oil being leaked into the sea in the Singapore Strait. Although the cleanup is ongoing, it appears no additional oil is leaking from the vessel.

While large, the BP spill has not yet surpassed that of the biggest to occur in the Gulf of Mexico, though depending on estimates it is coming close. In 1979, a drilling rig in Mexican waters, the Ixtoc I, blew up, releasing 140 million gallons of oil [Wiki]. The well cap in that case took 10 months to seal [List of oil spills].

tvnewswatch, Beijing, China

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