From the “I-never-thought-I’d-use-this-class” file, I took a semester course once from an oil spill expert. Professor Ed Gilfillan had studied the response of Prince William Sound to various clean-up regimens following the wreck of the Exxon Valdez, and we spent weeks learning about chemistry of oil spills and the factors involved in ecological recovery. The class was over 15 years ago, mind you, and in retrospect I remember only two things.
But these are two very key things, and they are both relevant to the ongoing tragedy in the Gulf of Mexico.
1. The soil structure at the coastline will determine whether the oil lingers for weeks or for decades. Coarse pebble beaches are a best-case scenario, as their component parts (the pebbles) have less surface area for oil to cling to than sand or silt, and their interactions with waves help remove and disperse the oil. Conversely, fine silt of the sort one finds in tidal marshes retains oil for many years.
The coastal wetlands around Louisiana and Alabama are about the worst kind of place for an oil spill. Once the slick oozes ashore it’ll settle in for the long haul. Significant amounts of oil will linger in that mud for decades.
2. Clean-up can cause more damage than the oil spill itself. Oil kills, but whatever survives the initial oiling isn’t liable to survive the subsequent pressure-washing and dredging, not to mention the constant intrusion of machinery and foot traffic. For example, remediation efforts after Exxon Valdez may have delayed recovery by two years. Physical methods of removing the oil have the same biological results as bulldozing. Chemical methods (detergents) might be less damaging, although from what I understand not enough is known about their long-term effects.
In the wake of a big spill, governments and oil companies often receive intense political pressure to be seen doing something. That’s probably a good thing, especially at the containment phase before the oil disperses, but there are more productive and less productive ways of doing something. Conducting a massive- and highly visible- physical cleanup may not help the Gulf recover any faster, even if it helps remediate the public image of the culprits.
If BP is to do penance for this accident, in the long view it makes more sense for them to invest in better systems for containing and preventing the next spill. Once this oil hits the coastal marshes, the damage is largely done.