The Deepwater Horizon oil spill released roughly 4.9 million barrels of crude oil into the northern Gulf of Mexico in the spring and summer of 2010, and the underwater wellhead continues to leak about 100 gallons of crude every way. One pressing question to arise from the spill is whether or not Gulf seafood that was exposed to crude oil and the dispersant used to break up the spill is safe for human consumption. A study in mBio this week tested whether oil, the dispersant, or a combination of the two might affect the microbes of the human digestive tract and found that high concentrations of oil combined with dispersant are detrimental to these helpful microbial communities, but the low to undetectable concentrations typically found in Gulf shellfish had no discernable effect.
To accelerate dispersion and enhance breakdown of the oil by microorganisms, 1.5 million gallons of the dispersant COREXIT 9500 were sprayed on the surface of the Deepwater Horizon crude oil spill and applied at the underwater source of the leak. Concerns were soon raised about the safety of that dispersant for wildlife, plants, and humans alike. Oysters, shrimp, and other delicacies could well bioaccumulate oil or dispersant in their tissues, so eating contaminated shellfish presents one possible route by which humans could be exposed to these materials.
But what are the potential health impacts of consuming crude oil and dispersant? Although studies of the toxicity of crude oil and COREXIT 9500 to the human body have been carried out, no one has explored whether the dispersant or a mixture of oil and dispersant could have an impact on the microorganisms that line our intestinal tracts and aid in digestion, enhance immunity, and manufacture essential vitamins that the body absorbs.
Scientists working for the National Center for Toxicological Research at the U.S. Food and Drug Administration (NCTR, FDA) tackled the problem. The researchers combined human fecal samples, which are loaded with the microorganisms that reside in the intestines, with varying quantities of Deepwater Horizon crude oil and the dispersant, then tested the samples to see how the microorganisms fared.
Click on teh source link to read more on mBio's blog, mBiosphere...