EPA Approves Questionable Dispersants

[amborin]

BP and federal officials are also engaging in one of the largest and most aggressive experiments with chemical dispersants in the history of the country, and perhaps the world.
With oil continuing to gush from the deep well, they have sprayed 160,000 gallons of chemical dispersant on the water’s surface and pumped an additional 6,000 gallons directly onto the leak, a mile beneath the surface.

John Curry, director of external affairs at BP, said the company was encouraged by the results so far. But some environmental groups are deeply nervous.

“I understand it’s the only thing they can do,” said Paul Orr of the group Lower Mississippi Riverkeeper. “But I think it’s vital afterwards to really monitor what’s happening with aquatic life, with oil on the sea floor and things like oyster beds.”

Even in the best cases, dispersants are applied in what might be termed a lose-lose strategy. Scientists make the calculation that it is better to have the ocean filled with low concentrations of the dispersant chemicals — which are in themselves mild to moderate poisons — than to have dense oil on the surface or washing up onshore, places where it is most likely to harm wildlife.

And while most environmentalists support the application of dispersants as a necessary evil to limit the damage, some have assailed an industry policy that guards their chemical makeup. Keeping the exact mix secret makes it harder to evaluate the risks to marine ecosystems and to know what side effects to look for as the crisis unfolds.

What is more, the main dispersants applied so far, from a product line called Corexit, had their approval rescinded in Britain a decade ago because laboratory tests found them harmful to sea life that inhabits rocky shores, like limpets, said Mark Kirby, a scientific adviser to the British government on the testing, use and approval of oil spill treatment options.


http://www.nytimes.com/2010/05/06/science/earth/06dispersants.html?scp=1&sq=oil%20dispersants&st=cse

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Dispersant 'may make Deepwater Horizon oil spill more toxic'
Scientists fear chemicals used in oil clean-up can cause genetic mutations and cancer, and threaten sea turtles and tuna

By Suzanne Goldenberg

Chemicals used to break up the Deepwater Horizon oil spill before it reaches shore could do lasting damage to the waters of the Gulf of Mexico, environmental scientists say.

By BP's own account, it has mobilised a third of the world's supply of dispersant, so far pouring about 140,000 gallons (637,000 litres) of the cocktail into the Gulf as of today. Some of the dispersant has been injected directly into the source of the spill on the ocean floor, a technique never deployed before, deepening concerns about further damage to the environment.

The dispersants are designed to break down crude into tiny drops, which can be eaten up by naturally occurring bacteria, to lessen the impact of a giant sea of crude washing on to oyster beds and birds' nests on shore. But environmental scientists say the dispersants, which can cause genetic mutations and cancer, add to the toxicity of the spill. That exposes sea turtles and bluefin tuna to an even greater risk than crude alone. Dolphins and whales have already been spotted in the spill.The dangers are even greater for dispersants poured into the source of the spill, where they are picked up by the current and wash through the Gulf.

The high demand for dispersant carries an additional risk. As BP runs through stocks of the chemical, called Corexit, scientists fear it will fall back on older stockpiles in the developing world that are more toxic than those approved for use in the US. "You are trying to mitigate the volume of the spill with dispersant, but the price you pay is increased toxicity," said Richard Charter, a scientific adviser to Defenders of Wildlife. "There are no good answers in a mess of this size."


http://www.biologicaldiversity.org/news/center/articles/2010/guardian-05-05-2010.html


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.....to the indignity of oil oozing into its depths at a rate of at least 5,000 barrels per day, the Gulf of Mexico is now enduring a heavy rain of mystery chemicals.

BP and the U.S. Coast Guard are dumping large amounts of "dispersants" both on the surface and underwater, in a desperate attempt to control the ongoing spill. Dispersants are surfactants, not unlike what you use on your dishes, that break oil down into small droplets that sink into the water. .

How much are they dumping? Lots. According to ProPublica, "BP has already bought up more than a third of the world's supply" of dispersants. On Thursday alone, ProPublica reports, emergency workers dropped 100,000 gallons of the stuff into the Gulf.

And what precisely are they dumping? That's where the mystery comes in. "The exact makeup of the dispersants is kept secret under competitive trade laws," Propublica reports.

What? Let me get this straight. A huge oil company is pumping massive amounts of oil directly into public waters, imperiling the health of some of the globe's most productive fisheries -- as well as communities around the coast. To try to minimize the effects of the ongoing spill, the company starts dumping chemicals into that same public water. And not just a little -- a third of the global supply is on hand. And we don't have the right to know what those chemicals are? That's a scandal.

Propublica did manage to identify one product currently being used, called Corexit, which includes 2-butoxyethanol, a "compound associated with headaches, vomiting and reproductive problems at high doses."

snip

The dispersant strategy seeks to limit coastal damage by moving oil from the surface to the ocean's depths, where it remains stationary and can't drift to the coast. Of course, the ecological burden of the spill is pushed below the surface -- with potentially devastating consequences.

The strategy is controversial among marine biologists. In 2005, the National Academies Press published a book on the topic, available for online reading, authored by the Ocean Studies Board. The report reveals that serious questions remain about the wisdom of using dispersants to treat spills.

The report states that most research on how fish deal with chemically dispersed oil don't account for how sunlight might magnify ill effects. The report puts it like this:

he possibility of photoenhanced toxicity and particulate/oil droplet phase exposure is generally not considered. A number of laboratory studies have indicated toxicity due to PAH increases significantly (from 12 to 50,000 times) for sensitive species in exposures conducted under ultraviolet light (representative of natural sunlight), compared to those conducted under the more traditional laboratory conditions of fluorescent lights.
In other words, most tests have been done under lab conditions; but when you perform them in actual sea conditions -- ie, with the sun shining -- things look considerably worse. That's a chilling thought, given what is now happening in the Gulf.

Scandinavia has had its share of oil spills over the years, so I contacted Hans Ulrik Riisgård, professor at the Marine Biological Research Centre at the University of Southern Denmark, to get his perspective on dispersants. Putting the matter of possible toxicity of the dispersants aside, Riidgard replied via email that that dispersants remove oil from the sea surface rapidly, "making the oil concentration many times higher than it would have been due to natural dispersal (wave action etc.)."

He continued: "Therefore, use of dispersants will most often lead to a much larger exposure of marine

http://www.grist.org/article/2010-05-03-how-risky-is-the-dispersant-strategy-for-addressing-the-gulf-spi/

[G_j]

1. our poor oceans!... kick