EPA on Oil Dispersants: No More Toxic Than Oil Alone

By Joseph Calamia | August 3, 2010 6:23 pm

471883main_gulf_amo_2010209What do you get when you mix oil and dispersants? A mixture that doesn’t seem to be more toxic than oil alone, the EPA said yesterday. Their statement came after a second round of testing eight oil dispersants.

The EPA tested the response of two sensitive Gulf species, the mysid shrimp and a small fish called the inland silverside, which they exposed to mixtures of dispersants plus oil and to oil alone.

The results indicate that the eight dispersants tested are similar to one another based on standard toxicity tests on sensitive aquatic organisms found in the Gulf.  These results confirm that the dispersant used in response to the oil spill in the Gulf, Corexit 9500A, is generally no more or less toxic than the other available alternatives. [EPA statement]

Chemical dispersants help break down oil, in theory putting it in a form easier for microbes to consume. Still, dispersants are toxic, and BPs unprecedented use of huge amounts of Corexit worried EPA officials, who were uncertain of the chemical’s long-term effects. Reportedly, BP and the United States Coast Guard have not used dispersants since July 19, when the leaking well was successfully fitted with a temporary cap.

The tests prove that the oil itself, not the dispersants, is “enemy No. 1,” Paul Anastas, EPA assistant administrator for research and development, told reporters on a conference call. [CNN]

Still, Anastas says EPA scientists have more research to do on the lingering effects of dispersants:

“The type of acute toxicity we’re discussing today is only one part of the hazard,’’ he said. Another is the health effects of the breakdown products of the dispersant, which the agency has yet to investigate. [New York Times]

As we reported yesterday, since the temporary cap was put in place oil slicks have been quickly disappearing from the surface of Gulf waters. Some say that the oil evaporated, that sunlight broke it down, or that the dispersants helped microbes eliminate it:

Adm Thad Allen, the national incident commander, said: “It’s becoming a very elusive bunch of oil for us to find.” … By some estimates, up to 40 per cent of the oil may have evaporated as soon as it reached the surface. Experts said that warm surface water and weeks of sunlight had broken up the crude, along with strong winds and waves during storms last week. The Gulf’s waters also contain bacteria that have always degraded oil that seeps naturally from the ocean floor. [The Telegraph]

But the fact that the oil is quickly disappearing from the water’s surface doesn’t have everyone celebrating. As Discovery News reports, researchers have seen such vanishing acts before only for the oil to reappear on shore, as happened with the 1979 Ixtoc I oil gusher which also used dispersants. Larry McKinney, who worked on that spill, said he fears that the oil will mix with sediment and sink to the continental shelf.

“It’s a race,” McKinney said. “Can the microbial activity eat up the oil before it mixes with sediments and sinks? … BP used a lot of dispersant and the oil went someplace,” McKinney said. [Discovery News]

Related content:
80beats: BP Prepares for “Static Kill” Operation to Permanently Seal Leaking Well
80beats: One Cap Off, One Cap On: BP Tries Another Plan To Catch Leaking Oil
80beats: Photos From the Gulf’s Great Sea Turtle Relocation
80beats: Gulf Coast Turtle News: No More Fiery Death; Relocating 70,000 Eggs
80beats: Next from X Prize: An Award for Cleaning up BP’s Oil Spill?

Image: NASA

CATEGORIZED UNDER: Environment
  • http://Untitledvanityproject.blogspot.com Rhacodactylus

    WOOOOOOT, Finally a victory! The dispersant and oil aren’t MORE toxic than oil alone. Ladies and gentlemen at BP, looks like it’s Miller Time.

  • Brian Too

    Shouldn’t the minimum standard be, the dispersant has to be less toxic than the oil? And by a good margin too, say 10-1000X. Otherwise, you’re just making a toxic mess bigger by adding to it.

  • JJ

    Over 75% of the spill has been burned, collected, evaporated, or dispersed by the last storm and processed by bacteria. BP has also begun plugging the well and it’s going as planned, should be completed in the next 2 to 3 weeks. Things are looking good.

    The dispersant is basically glorified soap, it’s not a stretch to say it’s no more dangerous than oil itself. The biggest risk with dispersant is irritation to mucus membranes (nose, throat, lungs, eyes), it’s really no more dangerous than household cleaning products. As for sea life, it seems to be safe, as far as we know. The EPA hasn’t said anything about dispersant being toxic to sea life and they wouldn’t have approved its use if it was deemed so.

  • fatkid

    JJ- You are cherry picking and you know it. And the crack about the EPA isn’t even worth rising to the bait.

    Why dont you go to Drudge or some other right wing apologists site? I’ve read your posts, they get to be many times longer than the original article, arguing the company line. Arent there any other trolls to agree with under your bridge?

  • http://thekolinskichronicle.com/ Bruce J. Kolinski

    I don’t buy any of this BP / Government / environmentalist collusion. Dump oil on your back patio, driveway or even better in your swimming pool. Then grab a chair and wait for it to disappear. I would suggest a comfortable chair because you will be waiting a very long time.

    BP dispersed this oil so it isn’t readily visible. The oil is not gone. Oil consuming bacteria did not suddenly bloom and then vanish beneath the magician’s hat. It did not suddenly transform itself into air. We now have no idea what the scope of the problem or damage might be. We do know that however this plays out, BP is now off the hook, even Rush Limbaugh says so, and we, the uninformed tax payer will be picking up 100% of the tab; and the sea life and the Gulf Coast residents – well who really cares about that?

    The environmental movement has proved once again that their agenda is Marxism, not the environment. Screw the Gulf of Mexico; Marxist Obama must be protected at all costs. Sometimes being a human is a disgrace. This is one of those times.

  • carole

    jj: funny, I’ve heard that only 10-20% of oil has been collected or burned. The rest has been sprayed with toxic chemical dispersant corexit9527, which is nasty stuff, banned in the UK and other countries since 1998. Remember Exxon Valdez? 20 years later, most cleanup workers are dead due to the dispersant corexit. The oil is still there, scientists estimate it will be there for at least another 20. And that was really a “spill”. The Gulf catastrophe is so huge it doesn’t even compare. “We will restore the Gulf”…ya right, not in my lifetime. The oil is purposely being sprayed to sink/hide it, probably because its cheaper than cleaning it up responsibly.

  • carole

    ps, jj, there have been dozens of massive fish kills all over the Gulf, photos with dead fish as far as the eye can see. Now there are several fish kills along the east coast. But keep on looking through those rose colored glasses, its a heck of a lot less depressing than THE TRUTH.

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

80beats

80beats is DISCOVER's news aggregator, weaving together the choicest tidbits from the best articles covering the day's most compelling topics.
ADVERTISEMENT

See More

ADVERTISEMENT
Collapse bottom bar
+

Login to your Account

X
E-mail address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »