Guest Post: Scientists Say Dispersants May Delay Recovery of the Gulf By Years … Or Decades

Washington’s Blog

The government and BP claim that the combination of Corexit and crude oil is less toxic than crude oil by itself.

Is that true?

Well, scientists have found that when Corexit is applied to the actual crude oil from BP’s well, it releases 35 times more toxic chemicals into the water column than would be released with crude alone.

And the tests conducted by the EPA which purport to show that dispersant plus crude is less toxic than oil alone used a combination of Corexit with Louisiana light crude oil. However, the oil coming out of BP’s leaking well contains an unusually high concentration of methane. As CBS notes:

The oil emanating from the seafloor contains about 40 percent methane, compared with about 5 percent found in typical oil deposits, said John Kessler, a Texas A&M University oceanographer who is studying the impact of methane from the spill.

It is doubtful that the EPA used such unusually methane-rich oil in their testing.

More importantly, EPA toxicity tests on the dispersant-oil mixture were conducted at sea level pressures (in other words, the pressure at the surface of the ocean). But enormous quantities of Corexit have been applied 5,000 feet under the ocean at the leaking wellhead.

As the New York Times noted in May:

There has been significant research in response to spills over the past few decades, especially the Exxon-Valdez spill in Alaska in 1989 and the Prestige spill in 2002 off the coast of Spain.

But all of the scientific precedent is from spills from tankers or near shore.

“We are working with reliable knowledge from that science,” Plumb said, “but it is limited and not across the scale or scope of the ecosystem we are in now.”

Scientists and responders are prepared to deal with oiled birds and shoreline effects, because those are the usual problems. An ongoing oil spill a mile under water is unchartered ground.

“We’ve never dealt with this kind of deep water, we’ve never dealt with this amount of dispersants, we’ve never dealt with the Gulf,” [Roger Helm, chief of the contaminants division of the Fish and Wildlife Service] said. “We’re in a very early phase of the science here; there is not a lot of experimental work or practical work upon which to base the work we’re doing.”

Marine biologist and toxicologist Dr. Chris Pincetich – who has an extensive background in testing the effects of chemicals on fish – told me yesterday that scientists have no idea what compounds will be formed when Corexit dispersant and oil interact under the high pressures present at BP’s deepwater spill site (Dr. Pincetich directed environmental toxicity testing as a consultant and lab supervisor for many years, and now works to protect endangered sea turtles at the Sea Turtle Restoration Project,

And as Scientific American notes, breakdown products from the dispersant might be toxic as well:

For example, more testing will be needed to determine if the breakdown of Corexit 9500 – either into other chemicals or when metabolized by animals – produces toxic products of its own. “In toxicology, it’s quite often not the original compound that’s the toxic entity,” [toxicologist Cary Mitchelmore of the University of Maryland, who co-authored a National Research Council report on dispersants in 2005] notes.

Indeed, even Sergio Alex Villalobos, toxicologist for Nalco – maker of the Corexit dispersant – says:

Once it’s mixed with oil, that’s where you get the most impact, that’s where you see most of the toxicity.

Government Testing is “Embarrassing

Dr. Pincetich says that he’s “embarrassed” that the government is using inadequate tests regarding the toxicity of Corexit. For example, when I asked whether he thought the EPA’s screening level for Corexit in the Gulf of 750 parts per million is based on sound science, Dr. Pincetich said no. He pointed me to a 1996 study which found that exposures of less than 20 ppm can adversely affect abalone.

Dr. Pincetich also noted that the tests being used in the Gulf are not the standard type of tests used to measure toxicity of long-term chronic exposure, but are typically only used for initial screening of effluent from coastal dischargers. There is no scientific evidence to support using only such a short-term, acute exposure test. The EPA training manual contains dozens of better testing protocols, and toxicity tests are usually run on 7 different species when there is a screening of unknown toxic chemicals involved (and even basic national pollution discharge standards require testing for 3 species), but – in the Gulf – the EPA has only been testing using 2 species.

Dr. Pincetich has also noted that EPA toxicity testing for Corexit is woefully inadequate, since EPA testing was only for mortality and only used a 48- and 96-hour time frame. His doctoral research found that fish that were alive at 96 hours after exposure to pesticide were dead at two weeks, so the chemicals were considered non-lethal for the purposes of the test:

Dr. Pincetich explained that many standardized EPA bioassay toxicity testing protocols exist to measure growth and reproduction in marine early life stage organisms, but EPA is just using the cheapest possible tests. He says that standard tests should be run, and BP should pick up the tab.

Corexit May Delay Recovery of the Gulf for Years … Or Even Decades

Dr. Pincetich told me that he believes that use of dispersant may – in certain circumstances – delay recovery of the ecosystem for years.

Indeed, PhD toxicologist Ricki Ott noted in a New York Times Op Ed that dispersants like Corexit can persist in the ocean for decades:

[Dispersants] can linger in the water for decades, especially when used in deep water, where low temperatures can inhibit biodegradation.

Some experts have also said that the use of Corexit has prolonged by decades the presence of toxic crude oil, because the dispersant sinks the oil beneath the ocean surface, where it cannot be quickly broken down by sun, waves and microbes.

And the head of Lawrence Berkeley National Laboratory’s Ecology Department – Terry Hazen – argues that the use of dispersants can delay recovery of ocean ecosystems by decades:

Hazen has more than 30 years experience studying the effects of oil spills. He says the oil will be damaging enough; toxic dispersants will just make it worse. He points to the 1978 Amoco Cadiz Spill off the coast of Normandy as an example. He says areas where dispersants were used still have not fully recovered, while areas where there was no human intervention are now fine.

As Hazen has noted:

“The untreated coastal areas were fully recovered within five years of the Amoco Cadiz spill,” says Hazen. “As for the treated areas, ecological studies show that 30 years later, those areas still have not recovered.”

Admittedly, chemicals other than Corexit were used in the Amoco Cadiz spill. But the precautionary tale still holds: chemicals should not be applied to oil spills unless scientists are positive that they will provide a net long-term benefit.

Disturbingly, Corexit is apparently still being sprayed in the Gulf. See this, this and this.

Print Friendly, PDF & Email
This entry was posted in Guest Post on by .

About George Washington

George Washington is the head writer at Washington’s Blog. A busy professional and former adjunct professor, George’s insatiable curiousity causes him to write on a wide variety of topics, including economics, finance, the environment and politics. For further details, ask Keith Alexander…


  1. Doc Holiday

    Re: “doubtful that the EPA used such unusually methane-rich oil in their testing”

    ==> Get real, the EPA has no tests, procedures or processes that can be taken into account for the chemical dynamics that are floating around in the Gulf … the charade that they have an understanding of what’s going on (out there) is pure bullshit and obviously PR for BP.

    Likewise, FDA, CDC, NASA, NOAA and the Coast Guard are all full of shit as well and that’s a F’ing shame that our own country relies on collusion to spin bullshit through hype — pretending that there is some model in place that explains what Corexit is doing to the tainted seafood that will be sold to retarded people that buy this crap!

  2. Debra

    I’m going to say a really dumb assed thing, here, and I hope you will forgive me…
    Crude oil COMES FROM nature. It is part of the plan. (Uh, don’t worry, I have no pretenses of knowing what the plan is, but I know that what is out there that we have not MADE is part of the plan…)
    Corexit is NOT PART of the plan…
    Should we be wondering at this point ?
    Anybody who has ever MADE anything knows that most of the time, when you fuck something up, trying to correct your mistake tends to make things worse.
    Very, very often. Most of the time, even.
    Enough said.
    This article makes me very sad…

  3. John Emerson

    The federal response to the BP spill was astonishingly bad. This seemed like an area where Obama could have scored points, at no cost to himself, by doing the right thing. He chose not to.

  4. Steve

    It took the French over two hundred years of abuse before they started lopping off heads.
    I wonder what the tolerance level is of the American people what with food stamps, easy access to prescription and illicit drugs and really big TV’s.
    Maybe this time it’s different…

  5. sukibarney

    I’m no scientist but it stands to reason that if something ultimately needs to be cleaned up and removed up why would you want to disperse it making it more difficult to contain? Especially if it’s dispersed with something more toxic than the spill.
    EPA and the MMS= Dumb and Dumber. EPA,MMS and Obama= the 3 stooges

  6. PJM

    The current USA Government has the same pattern behaviour of URSS/Communists in the past. How can be possible this today? How much decay is needed to americans wake up and open their eyes?

    Its really sad.

    This episode will have more impact than were thinking today. I believe the impact of this american tragedy and the cover up and misbehaviour from american government will afect more the world than we think. This toxics will afect a large parte od the sea food production in the world. And with the current low level of food reserves, the changing in the weather patterns causing less food producion around the world, the QE by the dollar spreading inflation across the globe and, of course, the risk of proteccionism in the food sector, we will withness huges famines in some parts of the world in the next years.

    This is sad. The colapse of American Empire will be dramatic to all of us. Not only americans.

    I hope to be wrong but I believe Im right. And I dont speculate in food commodities. Is against my basic principles. But doing a mere analysis to the food markets Im seeing the right conditions to see one of great bull market ever seeing in the last three hundred years in commodities. Just doing a simple analisys to the market, to the lowest levels of food reserves in decades, eigtheen years of food producion increasing that was a winning stake in a row that inst statistically sustainble and, to be more dangerous, a lot of money created by central banks and government spending through the economic system.

    This american tragedy in the Gulf will afect us around the globe. It was the most government incompetency in decades in USA. This tragedy and the Katrina tragedy show us how the big and powerfull american government has the same pattern behaviour of URSS communists governemts in the past. The government in USA is so big, with a lot of power and money, resources, human resoruces and so on, but is so incompetent, with nasty leaders and one puppet as President, that I cant believe how could be this possible in… USA.

    Wake up americans. Wake up before the tipping point. What is happening in the USA is a high level of corruption, incompetence and sofisticade fascim. Wake up before is too late.

Comments are closed.