Gulf of Mexico Oil Spill

(from Jersey Coast Anglers Association June 2010 Newsletter)

The catastrophic explosion and resulting fire, and the eventual sinking of the oil drilling rig, Deepwater Horizon, some 50 miles off Louisiana’s coast is both a human and environmental tragedy. Not only did it result in the deaths of 11 oil workers and injury to scores of others, but it has the ever increasing potential of being the most devastating and ruinous oil spill to our natural resource systems that this country has ever experienced.

Fortunately, New Jersey has not had to deal with anything similar to the type or size of the Deepwater Horizon spill, though the ones we have experienced share many of its important characteristics. While we have yet to determine the cause of the explosion and fire on the Deepwater Horizon and why the blowout preventer at the wellhead did not work, based upon our experience such calamities are caused 90% by human error and 10% by equipment failure. Preliminary information indicates that the blowout preventer, a fail-safe device design to seal an oil well in event of an accident, had a leaky hydraulic valve and had undergone modifications that made it difficult to operate. Also, a battery system to operate the valve was apparently not functioning.

The amount of oil being released always seems to be unknown or greatly underestimated during the critical first few days of the spill. The spill estimate given by the energy giant BP after the Deepwater Horizon burned and sank first range from no leakage at all to 5,000 gallons a day, then to 10,000, 50,000, 150,000 and eventually to 210,000 gallons. Some experts now believe it is five times the 210,000 number. In reality we will probably never know the exact amount, we never do. In our experience with tanker spills in New Jersey, even when knowing the capacity of the ship, the spill amount is at best an estimate. In the example of the Exxon Valdez, even 20 years after the most scrutinized oil spill in our country’s history the experts can only agree that the oil spill ranged between 10.9 million and 38 million gallons.

We have found with our spills in New Jersey that even though the first line of defense is the rapid deployment of oil containment booms and oil skimming equipment, in reality they prove to be inadequate. Containment booms are solid, but flexible rubberized fabric which float at the water surface and extend down some 4-5 feet. The float at the top of each boom extends some 8-12 inches above the surface. The booms are designed to contain the spill at the surface so it can be removed with skimmers or vacuums. Containment booms are not at all effective in containing oil suspended in the water column and only partially effective in containing oil at the surface if currents are less then ½ knot and waves are less than about 6 inches. Currents stronger than 1 or 2 knots or waves higher than 1 or 2 feet render containment booms nearly useless because the oil is swept either over or under them. Based on past spills in marine environments, the best we are able to recapture is 3% of the oil. In ocean waters it is considerably less than that.

More than 200 thousand gallons of dispersants have been spread on the oil slicks occurring in Gulf waters. Dispersants break the oil into small particles and drive it away from the surface into the water column, similar to what happens when adding dish detergent to a greasy cooking pan. The action of oil dispersants can lessen the amount of oil making it to the shoreline and striking vegetation such as salt marshes. However, from a fishes well being dispersants have a much more detrimental biological impact than oil alone. Now, not only is there more surface area of oil that becomes available for direct contact with fishes, but to the forage fishes and other marine life which they depend for food. In addition, the smaller oil particles are dispersed throughout the entire water column and can remain there for a long period of time, thus making them more available for direct contact with fishes. And to make matters worse for fishes, various chemical components of the dispersant are toxic in themselves to not only fishes, but to a great multitude to other marine organisms.

The petroleum hydrocarbons which constitute the oil of a spill are very complex chemical compounds. A series of these compounds (polycyclic aromatic hydrocarbons) are known to be toxic to fish as well as humans, some having been shown to cause lung and skin cancer as well as reproductive problems. When these compounds come into contact with the fishes, either directly or through their food, they can suffer lethal effects, long-term debilitating problems or have serious impacts on their offspring. For example, sea herring larvae occurring in the Exxon Valdez oil spill area of Alaska exhibited 2-3 times the deformities than did healthy herring found outside the spill area. And runs of salmon occurring in the same oil spill area had two year-class failures following the spill as compared to salmon runs in non-affected areas.

In addition to the known toxic effects of oil spill on fishes and other marine life, the Deepwater Horizon spill has been found to have yet another impact. Scientists are now finding large masses of oil, some as large as 10 by 30 miles and 300 feet thick suspended in the water column several hundred feet below the surface and the thermocline. As biological decomposition of the oil takes place, oxygen dissolved within the water column could become exhausted resulting in hypoxia or even anoxia. Such a condition would result in killing all marine life!

What we know of oil spills is that there will be no advantages or benefits to fish life, only disadvantages and damages. Any actions that are taken to clean up the Gulf oil spill will be merely attempts to keep the damages as small as possible, albeit in the end, we are unable to reduce oil spill damages any appreciable amount. Unfortunately the real impact of the Deepwater Horizon oil spill will not be fully understood for many years. In the mean time, the major biological damage will occur to marine life and fisheries will be closed in order to protect the well being of consumers.

Bruce Freeman has been part of the DEP oil spill response team for more than 15 years.

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