Corexit

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A C-130 Hercules sprays Corexit in the Gulf of Mexico (May 2010)

Corexit is the brand name of a line of oil spill dispersants and beach cleaners manufactured by the Nalco Company .

In 2010, with Corexit EC9500A and Corexit EC9527A, dispersants were used to a previously unknown extent by the oil company BP to combat the oil spill in the Gulf of Mexico in 2010 due to the disaster on the Deepwater Horizon offshore oil drilling platform . According to the EPA, around seven million liters of the dispersants were sprayed. Its use was controversial in particular because of the high ecotoxicity of the agents compared to other dispersants .

Brand history

The first Corexit products were developed by a subsidiary of the Exxon oil company in the late 1960s. It has been in regular use since then, in 1979 Corexit 9527 after the disaster at the Sedco 135F oil rig , at the time the largest oil spill in history, or the Exxon Valdez tank disaster in Alaska in 1989. In 1994, the Exxon Chemical Company brought the product range into a joint subsidiary with the water treatment company specialized chemical company Nalco, the Nalco / Exxon Energy Chemicals, which in 2001 after the takeover of the Exxon shares completely in Nalco.

In Great Britain, the European country that relies most heavily on the use of dispersants in oil spills, Corexit dispersants have not been permitted since 1998 because of the excessively high toxic effect in a test that simulates rocky coasts.

After the Deepwater Horizon disaster, BP bought all stocks of Corexit. As a result, Nalco's share price rose ten percent in May 2010. By selling the agent to BP, Nalco, which has a workforce linked to the oil industry, has made $ 40 million in sales since the explosion. On May 19, 2010, the United States Environmental Protection Agency requested BP to select and use less toxic alternatives to Corexit from the list of EPA-approved products within 24 hours.

Corexit EC9527A and EC9500A

The components of the products classified as hazardous substances are known from the manufacturer's safety data sheets . All components have been known in detail since June 2010 due to publication by the Environmental Protection Agency , but information on the exact composition is still not public. The manufacturer had previously stated that there were a total of six components. The safety data sheet lists the following hazardous substances as components of Corexit EC9527A, formerly known as Corexit 9527: the solvent 2-butoxyethanol , salts of organic sulfonic acids , which are surfactants, and a small proportion of propylene glycol . For Corexit EC9500A, formerly known as Corexit 9500, the following hazardous substances are listed: hydrogenated light petroleum distillates (petroleum-like solvent), salts of organic sulfonic acids (surfactants) and a smaller proportion of propylene glycol. According to information from the manufacturer Nalco to the US Environmental Protection Agency (EPA), Corexit contains the following substances: docusate sodium , sorbitan monooleate , polysorbate 80 , polysorbate 85 , propane-1,2-diol and butylglycol .

According to the approval data of the Environmental Protection Agency, Corexit EC9500A and EC9527A are more toxic and less efficient than dispersants from other manufacturers. Corexit EC9500A achieves dispersion effectiveness of 54.7 percent for South Louisiana crude oil , Corexit EC9527A 63.4 percent, while several other products achieve approximately 90 to 100 percent. The lethal concentrations LC 50 for New World earfish of the genus Menidia and hover shrimp of the genus Mysidopsis are between 2.6 ppm and 6.6 ppm compared to 25 ppm to 57 ppm for the most ecotoxic of the more effective products and 58.4 ppm to 100 ppm for the ecotoxic cheapest of the comparably effective products.

In experimental studies on cell cultures it could be shown that lung epithelial cells suffer cell death due to the influence of the above dispersants through necrotic , apoptotic and autophagic effects.

Individual evidence

  1. ↑ less toxic dispersants lose out in BP oil spill cleanup. In: New York Times. May 13, 2010.
  2. ↑ Marine Management Organization: Oil spill treatment products approved for use in the United Kingdom. ( Memento of April 21, 2014 in the Internet Archive ) (PDF file; 112 kB)
  3. ↑ Oil spill: Red card for chemical club Corexit. ( Memento from May 22, 2010 in the Internet Archive ) at: tagesschau.de , May 21, 2010, accessed on May 23, 2010.
  4. ^ National Contingency Plan Product Schedule. Environmental Protection Agency, May 13, 2010, accessed May 21, 2010 .
  5. ↑ Ingredients of Controversial Dispersants Used on Gulf Spill Are Secrets No More. In: New York Times. June 9, 2010.
  6. ^ Nalco Company: Nalco Releases Additional Technical Information About COREXIT. ( Memento of the original from March 8, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Press release. May 27, 2010. @1@ 2Template: Webachiv / IABot / www.nalco.com
  7. ↑ Safety Data Sheet Product Corexit® EC9527A. (PDF) (No longer available online.) Archived from the original on April 19, 2014 ; Retrieved April 18, 2014 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.fylrr.com
  8. ↑ Safety Data Sheet Product Corexit® EC9500A. (PDF) (No longer available online.) Archived from the original on April 19, 2014 ; Retrieved April 18, 2014 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.fylrr.com
  9. ↑ J. Sachs: Black gold lost in the sea. In: News from chemistry. 58 (9), 2010, pp. 900-902, doi: 10.1002 / nadc.201075940 .
  10. ^ Environmental Protection Agency: National Contingency Plan Product Schedule Toxicity and Effectiveness Summaries: Dispersants
  11. ↑ H. Wang, Y. Shi, D. Major, Z. Yang: Lung epithelial cell death induced by oil-dispersant mixtures. In: Toxicol Vitro . 26 (5), Aug 2012, pp. 746-751. PMID 22504303 .

literature

  • Rafael Mendonça Duarte, Rubens Tomio Honda, Adalberto Luis Val: Acute effects of chemically dispersed crude oil on gill ion regulation, plasma ion levels and haematological parameters in tambaqui (Colossoma macropomum) . In: Aquatic Toxicology . tape 97 , no. 2 , 2010, p. 134-141 , doi : 10.1016 / j.aquatox.2009.12.020 .

Web links