Responding to the months-long oil spill from a BP well in the Gulf of Mexico in 2010, a team of polymer chemists in Mississippi set to inventing a non-toxic chemical dispersant that could break up oily deposits without harming marine or wetlands wildlife.
How to Wash an Ocean - Testing Chemical Dispersants on Oil Spill Clean-Up
ANNE THOMPSON, reporting
April 20th, 2010. The largest oil spill in U.S. history.
BRIAN WILLIAMS (file): Good Evening, a slow-motion environmental disaster is taking place in the waters of the Gulf of Mexico. Crude oil is leaking into the seawater at a rate of 42,000 gallons a day. That's every day. That's right now.
THOMPSON: By May, slicks of oil from BP's well were seeping into Louisiana’s coast, home to some of the country's most environmentally sensitive wetlands. In the months that followed, thousands of birds were discovered with their feathers covered in oil, affecting their ability to float.
KERRY SANDERS (file): For those that are rescued, like these pelicans, there's now a backlog. It takes up to an hour to scrub each one.
THOMPSON: For a group of chemists at the nearby University of Southern Mississippi, the damage was shocking.
Dr. SARAH E. MORGAN (University of Southern Mississippi): My first reaction was to just be sick with worry over what was going to happen to the mammals, and the ocean, and the birds and fish because that's what's the wealth of that environment.
THOMPSON: Sarah Morgan and her colleague Daniel Savin saw the oil spill as a call to action. Within weeks, they wrote a proposal for funding from the National Science Foundation. Their plan: in only one year, they'd invent a compound to make the oil in the Gulf fall off anything it touched, including bird feathers. For years, chemistry has been used to create compounds like this, called dispersants. We use them every day in things like dish soap and laundry detergent. Dispersants help large globs of oil break down into smaller globs, making them easier to clean up.
Dr. DANIEL A. SAVIN (University of Southern Mississippi): If you take the analogy of using laundry soap, then you want the detergent to basically pull the oil and the dirt off your clothes. And then it goes through a rinse cycle. But in the ocean, you can't do a rinse cycle. So what you need to do is you need to have a compound, a dispersant, that's going to hold on to the oil, and not allow the oil to deposit onto the sand or on to bird feathers.
THOMPSON: The team from Southern Mississippi set out to create a polymer, a combination of molecules that are linked together in a long chain. The perfect mixture would need to both push water out while holding a droplet of oil in.
MORGAN: Some molecules like water more, we call those hydrophilic, they love water. Some molecules are hydrophobic, which means they don't like water, they hate water. And sometimes we can make molecules that have properties of both water-loving and water-hating.
SAVIN: And so the hydrophobic part is what actually captures the oil and holds on to it. And the hydrophilic part is what allows it to be stable in the water.
MORGAN: So, what we try to do in polymer science is design molecules that will give us just the type of attachment that we want, with just the type of dispersion that will maintain something dispersed within the water environment.
THOMPSON: BP had already sprayed one dispersant into the Gulf, 1.8 million gallons of it. But there were fears that this dispersant, called Corexit, could cause genetic mutations and cancer in marine organisms.
SAVIN: We do know that some of the components in Corexit could be potentially toxic. So, really the fundamental question from a research standpoint is how can you make a dispersant that works well, but would also be nontoxic.
THOMPSON: Back in Mississippi, the team relied on the same technology used in environmentally-friendly laundry detergents. They used plant-based materials.
SAVIN: And we ended up with a formulation that involved a compound called soy lecithin. And soy lecithin is an additive to chocolate, hat gives chocolate the smooth character. And so obviously soy lecithin is something that's edible, it's in food products.
THOMPSON: Finally, the time came to test the new dispersant. The question: would it prevent oil from clinging to a real duck's feather? In this demonstration, two aquariums are filled with simulated seawater, and into and a miniature oil slick colored with red food dye is poured into both of them.
SAVIN: What we're doing here is we have an actual duck feather that we could put into our oil slick. And as she pulls it out, you can see that all of the oil is sticking to the feather.
THOMPSON: But in the second aquarium, they add their new dispersant to the water and the oil. This time, the duck feather comes out clean, not a drop of oil on it. The particles made of oil and polymer solution settle to the bottom of the tank.
SAVIN: So what we're seeing is basically just the little pockets of sequestered oil in the water.
THOMPSON: Microorganisms that live in the waters of the Gulf should be able to break down the crude oil. After all, crude oil is a biodegradable fossil fuel, made from decaying plants and animals that lived millions of years ago. There's still more testing to be done on the dispersant, like trying it in actual Gulf seawater. But for now, Daniel Savin is confident that their solution can point the way to a more sustainable kind of chemistry.
SAVIN: You know, as with most problems, you don't realize it's a problem until something like this happens, until you have a major disaster.I think sustainability is a key issue for our future. Can we make a plastic that comes from a renewable resource? Can we make cellulose-based polymers, can we make polymers from corn and things like that?
THOMPSON: And when the next environmental cleanup has to happen, it may be a biodegradable polymer that saves the day.
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