Issues Raised by BP Oil Spill in the Gulf of Mexico

As the oil spill coming from BP's Deepwater Horizon exploratory drilling rig accidents (blowouts) of April 20 and 22, 2010 continues unabated, many questions are raised and many gaps uncovered in our knowledge. Most importantly, the long-term effects of such catastrophic spill on humans, marine life and environment are hard to predict, while various clean-up methods seem to raise a series of additional issues (such as the controversy related to the dispersants used). So far, few environmental issues became evident including:

• the formation of underwater oil plumes
• the danger from the dissolved contamination
• the impact of oil plume on the sensitive gulf coastal wetlands

While the oil continues to be spilled and scientists struggle to investigate and better understand and address, the long-term impact of the spill on environment, ecosystems and humans remains hard to predict.

Some Environmental Issues Raised by BP Oil Spill in the Gulf of Mexico

The long-term effect of the spill on the quality of marine water, marine organisms and humans remain hard to predict as the oil continues to be spilled unabated since the April blowout of Deepwater Horizon BP's drilling rig - about 52 miles offshore of Louisiana and in nearly 5,000 feet of water.

Below we point out few particular environmental issues with the spill so far - each of them raising questions related to the long-term effects of the spill and the potential to affect humans, too:

• Formation of underwater oil plumes - as pointed out by several independent research teams in the last month. The teams used fluorometer equipment which detects the fluorescence signature of oil's aromatic compounds - along with a sonar or light scattering instruments detecting oil droplets. Such observed underwater plumes include:
  1. A 6-mile wide oil plume between 3,200-4,400 feet below surface - this plume was observed on May 12, 2010 by a research team from University of Mississippi and it was located about 28 miles southwest of the wellhead.
  2. An even larger oil plume located about 42 miles northeast of the wellhead - pointed out recently by a research team from University of South Florida

It should be pointed that such observed plumes were not confirmed by the National Oceanic & Atmospheric Administration (NOAA). According to NOAA, more testing is needed to confirm the presence of such underwater plumes. However, a University of Georgia researcher has taken ocean saples from the area of the observed pkume which proved to contain oil. Such plumes were originally attributed to BP's underwater injection of chemical dispersants - a method tried for the very first time on the spill. Yet, such underwater plume may be caused by the spill itself due to natural dispersion. In fact, reports of such underwater plumes exist for other areas in the world where oil spill occurred. The plumes consist of oil and gas which pulls dense water from ocean's depth as they rise toward surface of water. The denser water slows down the ascent of the plume toward the water surface. It seems that the underwater applied dispersants will reduce even more the speed of plume ascension toward the water surface. Some scientists believe that dispersed oil plumes may spend more than a week in water before reaching the top.

• Long-term dangers from dissolved contaminationmay be exacerbated by the presence of underwater plumes and could raise serious problems as such dissolved contamination is not easily detected. Let us first explain the difference between dissolved oil contamination and oil plume (as a separate phase). Oil is not soluble in water which is why it floats on the surface of water. However, oil is a complex mixture of thousands of individual components (mostly hydrocarbons) which have various degrees of water solubility. Some of the higher soluble hydrocarbons are aromatic hydrocarbons (such as benzene) which could be quite problematic to the health of marine life and humans (especially if ingested with water). The main issues with dissolved contamination versus separate-phase plume relate to:
  1. Increased mobility as pollutants travel with water without any delays
  2. Increased absorption in living tissues and possibility of creating adverse health effects as it may bioaccumulate in living organisms
  3. The difficulty of detection as compared to the easily distinguishable (even by naked eye) separate phase oil floating on top of a water body

  The positive part of dissolved contamination is that it is more subjected to biological degradation and thus less persistent. Underwater reported plumes seem to contain larger amounts of dissolved contamination. In fact, more toxic dispersed oil may be more problematic than less toxic un-dispersed oil - which is one controversy confronting the application of dispersants. This seems to be more significant than the potential toxicity associated with dispersants by themselves (that is probably less than the potential toxicity of oil and especially dissolved oil components).

• Effect on sensitive gulf coastal wetland is another important environmental issue raised by the recent oil spill pollution. This is partially due to the particular conditions of wetlands which may preserve the oil for very long periods of time also impeding its successful clean-up. Wetlands are important habitats for a series of species including common seafood (shrimp) which use the wetlands at some point in their life. The oil may have significant effect on their life cycles. The presence of dispersants complicates the problem even farther and it remains hard to predict how the delicate natural equilibrium of such sensitive wetland ecosystems may be affected on a long-term basis.