It’s been over 3 years since the Deepwater Horizon offshore drilling rig exploded and sank, killing 11 people and dumping millions of gallons of crude oil into the Gulf of Mexico, yet oil still covers the ocean’s surface surrounding the explosion site.
During the months (yes, plural) that it took to plug the leaking well, the companies responsible deployed all sorts of flashy tactics meant to “contain” and “clean up” the toxic stew: skimmers and booms made from pet hair, aerial drops of dispersants meant to break down the waterborne oil, and teams of workers shoveling oily beach sand into trash bags.
The ocean floor and scores of dead dolphins beg to differ, and now science has backed up the skepticism. A new study published in the journal Environmental Science & Technology concludes that oil trapped in and around the sunken wreckage of the Deepwater Horizon is slowly making its way to the surface, resulting in continued sheen on the ocean’s surface.
The study was launched when the public complained about new oil floating at the ocean’s surface near the site of the sealed Macondo well. Many feared that the well, which took so long to plug, was leaking again. The researchers discovered that no, the well isn’t leaking (yay!); it’s just the same oil, which BP claimed to have cleaned up, still making its way to the surface.
“This appears to be a slow leak from the wreckage of the rig, not another catastrophic discharge from a deep oil reservoir,” said geochemist David Valentine of UCSB, in a press release. “Continued oil discharge to the Gulf of Mexico from the wreckage of the Deepwater Horizon rig is not a good thing, but there is some comfort that the amount of leakage is limited to the pockets of oil trapped within the wreckage of the rig.”
I guess you’ve got to take your silver linings where you can find them.
“To explain how the oil might be trapped and released from the wreckage, the scientists point out that when the Deepwater Horizon rig sank, it was holding tanks containing hundreds of barrels of a mixture of drilling mud and oil,” the release continues. “Over time, corrosive seawater can create small holes through which oil can slowly escape to the surface. The researchers suspect that the containers on the rig holding trapped oil may be the source of the recent oil sheen.”
So there’s no way to know if the sheen will ever truly go away.
Using comprehensive two-dimensional gas chromatography, a technique developed in Reddy’s lab, the researchers first confirmed that the sheen contained oil from the Macondo well.
Perhaps the only truly encouraging element of this news is that the ongoing investigation of the BP oil spill has allowed scientists to develop a geochemical analytical method that can help tie drifting oil to its true source.
“The ability to fingerprint synthetic hydrocarbons allowed us to crack this case,” Valentine said in the statement. “We were able to exclude a number of suspects and match the olefin fingerprint in the new oil slicks to that of the wreckage from the sunken rig.”
Although this surely isn’t the last big oil spill, not while offshore drilling is still a major element of Big Oil’s global domination, it could be one of the last times a company is able to deny responsibility for damages that extend beyond the visible. Being able to pinpoint the source of oil when found in the bloodstream of a sick dolphin or devastated oyster bed will be very handy when attempting to bring oil companies to justice.
Photo credit:SkyTruth on Flickr.