Myrmecos

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.

Comments

  1. #1 Angela
    May 5, 2010

    Here are two articles on the topic:

    “The concentration of detergents and other chemicals used to clean up sites contaminated by oil spills can cause environmental nightmares of their own,” says Terry Hazen, a microbial ecologist in Berkeley Lab’s Earth Sciences Division
    http://www.sciencedaily.com/releases/2010/05/100504142110.htm

    “Sometimes the cleanup itself can be as hard on the environment as the oil itself,” said Christopher B. Craft, the Janet Duey Professor in Rural Land Policy at IU Bloomington and past president of the Society of Wetland Scientists
    http://www.sciencedaily.com/releases/2010/05/100504135520.htm

  2. #2 norwegica
    May 6, 2010

    ..and ”
    Dispersant ‘may make Deepwater Horizon oil spill more toxic’

    Scientists fear chemicals used in oil clean-up can cause genetic mutations and cancer, and threaten sea turtles and tuna”
    http://www.guardian.co.uk/environment/2010/may/05/dispersant-deepwater-horizon-oil-toxic

  3. #3 Dave
    May 6, 2010

    I’m not sure that being right will keep you from collecting some flack for this post. Pictures of oil-covered birds are a powerful emotional tool, and no matter that few cleaned birds will survive, people tend to demand action. Black tar on beach trotting feet can cause quite a lot of complaints too.

    The microbial ecologist you quote above probably has their own agenda, but I would put money into bioremediation and keep the clean-up to high use areas. Oil is a natural product and has been leaking into the seas for eons. There must be lots of useful microbes that can be harnessed to fight the spills.

  4. #4 LolaBC
    May 9, 2010

    Why not use sawdust or light sand? It may be more labour-intensive, but surely less damaging.

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