BP Using Chemicals To Disperse Oil

Part of BP's response to the Gulf oil spill is the use of dispersants — chemical compounds that make oil more soluble in water. The company has bought up more than a third of the world's supply of the compounds, and has been using planes to unload hundreds of thousands of gallons of dispersants onto the oil slick. But dispersants have their own environmental impact. Ronald Tjeerdema, an aquatic toxicologist at the University of California, Davis, talks to Michele Norris about dispersants and their effect on marine life.

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MICHELE NORRIS, host:

With this massive spill, BP faces not one but two challenges. First, stop the oil from leaking. And second, figure out what to do with the thousands upon thousands of barrels of oil that have already leaked into the gulf. On that latter count, as we heard earlier, BP has begun using chemical compounds that help break up the oil. They're called dispersants.

For more now on how, and how well, these dispersants work, we're joined by Ronald Tjeerdema. He's an aquatic toxicologist and the chair of the department of environmental toxicology at the University of California, Davis. Welcome to the program.

Professor RONALD TJEERDEMA (Aquatic Toxicologist, University of California Davis): Thank you.

NORRIS: Help us understand how these dispersants that BP is using in the gulf actually work. What are they made of and what, exactly, are they doing to the oil?

Prof. TJEERDEMA: They are actually detergents that act very much like the detergents that you use in your kitchen to clean your dishes. They cut the grease and the oils not only from your dishes, but they also do the same for oil in the ocean.

NORRIS: So, does it work depending on, say, weather conditions or temperature of the water? And how much of it do they actually have to use?

Prof. TJEERDEMA: Actually, oil will disperse naturally in the ocean if there are strong enough sea conditions, wave conditions, etc. That will give you what's called natural dispersion. And when the ocean is not active enough, then by adding detergents, they will help the oil disperse into the water for you. And in general, the warmer the water, the more effective they are because the warmer the water, the more pliable, in a sense, the oil is as well.

NORRIS: Is this considered to be an effective way to disperse the oil and also help protect the marine life?

Prof. TJEERDEMA: It can be. It really depends upon the responders and what they're targeting as most important to predict. Dispersants can typically be used to protect organisms that live at the surface - for instance, birds and mammals who are at risk of coating. And in that regards, then they would use dispersants to quickly get the oil off of the surface so that it's not available for birds to dive into.

It also keeps the oil from hitting beaches and marshes, etc., by putting it down into the water column and getting it off the surface, where it will roll onto the adjacent beaches.

NORRIS: I'd like to get your response to something that was said by an expert on marine biology, someone who's a policy adviser for marine programs for the defenders of wildlife. His name is Richard Charter, and he says that there's a chemical toxicity to the dispersant compound that in many ways, is worse than oil. He says you it's a trade-off. You either have to try to minimize the damage coming to shore but in doing so, you may be more seriously damaging the ecosystem offshore. Your response to that?

Prof. TJEERDEMA: I'd say in general, I would agree with that. When you're looking at responding to a spill such as this one, you really have to make some trade-offs. You have to identify the resources, the organisms, the communities and so forth that are most at peril, and then design the response in order to best protect those.

NORRIS: As an environmental toxicologist, what most concerns you?

Prof. TJEERDEMA: My number one concern with this whole situation is the fact that they've not been able to stop the leaks yet. And until they do, anything that they're doing really is only treating the symptom of the situation.

NORRIS: Ronald Tjeerdema, thanks so much for your time.

Prof. TJEERDEMA: My pleasure.

NORRIS: Ronald Tjeerdema is an aquatic toxicologist, and the chair of the department of environmental toxicology, at the University of California, Davis.

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