What Happened to the Oil?
Filed under: Action,Gulf Oil Spill,News & Resources,Policy
(AP Photo/Dave Martin)
BP Deepwater Horizon Oil Budget: The Fate of the Oil – Ocean Leadership Perspective
On August 4th the federal government issued a report highlighting the components of a federal oil budget calculator. The conclusions in this report summarize the government’s and BP’s conclusions of the fate of the estimated 4.9 million barrels of oil that was spilled into the Gulf of Mexico from the BP Deepwater Horizon oil spill. According to these federal estimates, approximately 25% of the oil has evaporated or dissolved in the water; another 24% has been dispersed through natural or chemical means; and another 25% has been removed from the marine environment through direct recovery from the well head (17%), burned (5%) or skimmed (3%). That leaves 26% of the oil classified as residual or still in the water column, marine sediments or washed ashore.
These findings have been widely reported, and federal officials have been quoted, as suggesting that only one quarter of the oil remains in the marine environment and thus three quarters of the problem is effectively “gone”. However, there are a number of assumptions and significant uncertainties that need to be addressed through comprehensive sampling, monitoring and research before one can accept this conclusion.
Certainly, the Gulf of Mexico contains natural (physical, chemical, and biological) mechanisms for transforming, transporting, evaporating or diluting the myriad of chemical constituents in the oil. However, even if you accept the assumptions in this new federal report, upwards of 1.3 million barrels of oil remain in the Gulf, or the equivalent of five Exxon Valdez spills.
If one accepts the report’s assumption that 24% of the oil has been chemically or naturally dispersed into smaller globules in the water column, the question of how much is biodegraded still needs to be answered. How does the 1.8 million gallons of dispersant interact with the oil and effect the biodegradation rates of the myriad of compounds in the oil as well as the transfer rates of these compounds into marine organisms? In addition it is fair to assume that the 25% assigned to evaporation and dissolution processes will not be all evaporation. Thus, how much of the oil dissolved in the water is biodegraded and over what timescale? It is also reasonable to assume that a large proportion of the 26% assigned as residual will remain in the water column or sediments. Thus, there is significant research that needs to be accomplished before it can be assumed that only 25% of the oil remains in the Gulf.
One should also recognize that the microbial biodegradation of the thousands of organic compounds in oil favors the short chain hydrocarbons leaving behind the more toxic and often carcinogenic polycyclic aromatic hydrocarbons. Thus, it is essential to consider the chemical composition of the myriad of compounds resulting from the oil mixture over time and not just the amount of oil remaining in the water.
It is clear that we now need to establish a comprehensive long term research program in order to understand the effects of the spill on the ecology of the Gulf. We need to observe the chemical, biological and physical changes of the oil and its effects on the ecosystem from the wetlands to the deep water sediments. This will require federal leadership at the highest levels to develop, implement, and fund a coordinated, comprehensive and transparent science and monitoring initiative between the academic, federal and industry scientific communities. The American public needs to understand that this problem is not rapidly going away and based on previous oil spills, significant impact to the Gulf environment, ecosystems and communities will continue for many years.
Dr. Robert B. Gagosian
President & CEO
Consortium for Ocean Leadership
Note: Click here to download PDF version.
Pingback: 75% of the Credibility Gone « Stance and Balance