Study identifies source of oil sheens near Deepwater Horizon siteNews // August 12, 2013
A chemical analysis indicates that the source of oil sheens recently found floating at the ocean's surface near the site of the Gulf of Mexico Deepwater Horizon oil spill is pockets of oil trapped within the wreckage of the sunken rig.
First reported to the US Coast Guard by multinational oil and gas company BP in September 2012, the oil sheens raised public concern that the Macondo well, which was capped in July 2010, might be leaking.
However, both the Macondo well and the natural oil seeps common to the Gulf of Mexico were confidently ruled out, according to researchers from the University of California Santa Barbara (UCSB) and the Woods Hole Oceanographic Institution (WHOI). The results were published last month in the journal Environmental Science & Technology.
"Silver linings in the dark cloud of the Deepwater Horizon spill are very hard to come by," says Don Rice, program director in the National Science Foundation's (NSF) Division of Ocean Sciences, which funded the research.
"Among the precious few are the lessons we've learned about the marine biogeochemistry of petroleum mixtures. This team has demonstrated convincingly that we can also use what we have learned for forensic purposes."
The researchers used a recently patented method to fingerprint the chemical makeup of the oil sheens, and to estimate the location of the source based on the extent to which gasoline-like compounds evaporated from the sheens.
"The results demonstrate a recently developed geochemical analytical method and may have real-world implications in environmental management strategies for future contamination incidents," says Deborah Aruguete, programme director in NSF's Division of Earth Sciences, which co-funded the research.