Is Using Dispersants on the BP Gulf Oil Spill Fighting Pollution with Pollution?
An important question raised in this June 18, 2010 Scientific American article: Should we allow the use of toxic material to clean up other toxic materials? Here are just a couple of paragraphs lifted from the article. It's an important question, and I hope you'll take the time to read the full article:
"[T]here is no doubt that dispersants are toxic: Both types of the dispersal compound COREXIT used in the Gulf so far are capable of killing or depressing the growth of a wide range of aquatic species, ranging from phytoplankton to fish. "It's a trade-off decision to lessen the overall environmental impact," explained marine biologist Jane Lubchenco, director of the National Oceanic and Atmospheric Administration (NOAA), at a press conference on May 12. "When an oil spill occurs, there are no good outcomes.""
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The problem? The EPA's industry-generated data is unclear as to the relative toxicity of various dispersants. "If you think the data on COREXIT is bad, try to find any decent toxicology data on the alternatives," says toxicologist Carys Mitchelmore of the University of Maryland's Chesapeake Biological Laboratory, who helped write a 2005 National Research Council (NRC) report on dispersants. "I couldn't compare and contrast which one was more toxic than the other based on that."
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By last week, the EPA and Nalco had both released the ingredient list for COREXIT 9500 in response to widespread public concern. Its constituents include butanedioic acid (a wetting agent in cosmetics), sorbitan (found in everything from baby bath to food), and petroleum distillates in varying proportions—and it decomposes almost entirely in 28 days. "All six [ingredients] are used in day-to-day life—in mouthwash, toothpaste, ice cream, pickles," Ramesh argues. "We believe COREXIT 9500 is very safe."
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However, those solvents—petroleum distillates—are also known animal carcinogens, according to toxicology data, and make up 10 to 30 percent of a given volume of COREXIT. And those same everyday products can be deadly to wildlife. "It's the same products in Dawn dishwasher soap," Mitchelmore notes, which is being used widely to clean up oiled birds and other animals. "I wouldn't want to put a fish in Dawn dishwashing soap either. That would kill it."
As a result, the EPA ordered BP to stop spraying dispersants on the oil slick on May 26. The EPA also ordered BP to look for less toxic alternatives on May 20, and the company responded in a letter dated that same day that "BP continues to believe that COREXIT EC9500A is the best alternative." The dispersant continues to be sprayed onto the ongoing oil spill.
One reason BP can make such claims is due to a lack of clear data on any of the alternative dispersants. As part of the National Contingency Plan required for offshore drilling, one of 18 EPA-approved dispersants must be on hand to handle spilled oil. Each of those dispersants has been preapproved for use, and each of those dispersants has been tested—by the companies that make them—for toxicity using representative species of estuarine shrimp (Mysidopsis bahia) and fish (Menidia beryllina). Specifically, these animals are exposed to a mix of one liter of dispersant for every 10 liters of heavy fuel oil in water."
Whole article at this link: http://www.scientificamerican.com/article.cfm?id=is-using-dispersants-fighting-pollution-with-pollution&sc=CAT_SP_20100621