More scientists have come forward to criticize a US government report on the fate of the oil leaked into the Gulf of Mexico during the recent Deepwater Horizon debacle.
Earlier this month the National Oceanic and Atmospheric Administration stated that only 26% of the 4.9 million barrels that spewed from the BP well was “residual” in the Gulf. A number of scientists interviewed by Nature (see: Upbeat oil report questioned) and Science questioned the positive spin put on this report .
Now researchers from the respected Georgia Sea Grant programme have joined the fray. In their report they say that up to 79% of the oil from the spill remains.
“One major misconception is that oil that has dissolved into water is gone and, therefore, harmless,” says Charles Hopkinson, director of Georgia Sea Grant a researcher at thee University of Georgia Franklin College of Arts and Sciences (press release).
“The oil is still out there, and it will likely take years to completely degrade.”
At issue is the fate and danger of this distributed oil (a point also raised previously on this blog).
The NOAA report takes oil dispersed by chemicals or natural processes out of the ‘residual’ category, whereas the Georgia team leaves it in their ‘oil remaining’ category. Also, while NOAA puts evaporated and dissolved oil in one category, the Georgia report puts dissolved but not evaporated oil in the ‘remaining’ amount. The new report then tries to estimate how much of this distributed oil has has actually been completely degraded.
Another difference in the new report is a slightly lower overall amount of oil released. The Georgia team says 4.1 million barrels were actually released into the Gulf, as 800,000 were piped directly from the leaking wellhead to the surface. While this might seem a good thing, the smaller starting number means that higher percentage of oil remains in the system with this method of calculating (so maybe the top pie below should strictly speaking be bigger than the other pies, in the interests of graphical cohesion).
