On Thursday’s NewsHour, Spencer Michels reported on the ongoing controversy over the use of chemical dispersants in the Gulf of Mexico. BP has sprayed nearly 2 million gallons of dispersant — mostly a brand called Corexit — into the Gulf in order to break up the oil into smaller droplets that can be more readily consumed by microorganisms.
The EPA has said that using dispersant is better than the alternative — leaving oil to come ashore on beaches and marshes. And many scientists agree. But others are concerned about the unprecedented scale at which it’s been used, and worry that it could make its way into the Gulf food chain.
Among the researchers NewsHour producer Joanne Elgart Jennings spoke with was David Valentine, a geochemist at the University of California-Santa Barbara, who is studying how the Corexit might interact with the natural bacteria that usually break down oil in the Gulf. Below, Valentine demonstrates how Corexit and bacteria work to break down oil.
In addition to his work on dispersants, Valentine is also interested in the methane gas that has leaked into the Gulf along with oil from the well. In May, he proposed [using measurements of the methane]( http://news.discovery.com/earth/to-measure-the-oil-measure-the-methane.html) to help answer one of the [most vexing questions](http://www.pbs.org/newshour/rundown/2010/07/we-may-never-know-how.html) of the Gulf disaster — [how much oil has been leaked](http://www.pbs.org/newshour/rundown/2010/05/how-much-oil-has-spilled-in-the-gulf-of-mexico.html)? Now that the well has been capped, he says, the time is right to begin those measurements. Listen to him explain how below: