In it's Sunday edition, the Los Angeles Times attempts to unravel the "mystery" of oil dispersants.
The Times is reporting, "Mervin Fingas, a retired scientist with the Canadian government, said that of roughly 40 biodegradability studies he surveyed between 1997 and 2008, about 60% said dispersant retarded growth of oil-eating microbes and 15% reported no effect. The remaining 25% noted a positive effect."
And according to the Times, these "positive findings are open to interpretation."
Positive Finding? #1
- "At a 1999 oil spill conference, researchers reported that microbial populations dining on oil treated with the dispersant Corexit 9500 (used by BP in the gulf) grew more than seven times as large as those eating oil dispersed physically, suggesting the bacteria were helping. Yet a comprehensive 2005 review of dispersants by the National Research Council concluded that the healthy bacterial growth in such studies could easily be due to microbes feeding on dispersant, not oil."
Positive Finding? #2
- "A 2001 study by researchers at ExxonMobil Biomedical Sciences found that oil dispersed with Corexit 9527, also used on the BP spill, was twice as toxic to the inland silverside, an estuarine fish — but not if that crude had been exposed to the elements."
Unfortunately, "BP decided to spray much of the dispersant not onto the water surface, as is more common, but over oil pouring out of the leaking wellhead 5,000 feet under the sea," as the Times noted. This largely prevents crude from being "exposed to the elements" it normally would be on the surface by means of higher temperature, sunlight, air circulation, oxygen content, and wave action.