"There is a chemical toxicity to the dispersant compound that in many ways is worse than oil,” said Richard Charter, a foremost expert on marine biology and oil spills who is a senior policy advisor for Marine Programs for Defenders of Wildlife and is chairman of the Gulf of the Farallones National Marine Sanctuary Advisory Council.
Once they are dispersed, the tiny droplets of oil are more likely to sink or remain suspended in deep water rather than floating to the surface and collecting in a continuous slick. Dispersed oil can spread quickly in three directions instead of two and is more easily dissipated by waves and turbulence. But the dispersed oil can also collect on the seabed, where it becomes toxic food for microscopic organisms at the bottom of the food chain and eventually winds up in shellfish and other organisms. Moreover, experiments by John Nyman of Louisiana State University indicate that the combination of Louisiana crude and the dispersant used on the current gusher is more toxic to marsh-dwelling invertebrates than oil alone would be.
According to a 2005 National Academy of Sciences report, the dispersants and the oil they leave behind can kill fish eggs. A study of oil dispersal in Coos Bay, Ore. found that Polycyclic Aromatic Hydrocarbons (PAHs) accumulated in mussels, the Academy’s paper noted. Another study examining fish health after the Exxon Valdez spill in Alaska in 1989 found that PAHs affected the developing hearts of Pacific herring and pink salmon embryos. The research suggests the dispersal of the oil that’s leaking in the Gulf could affect the seafood industry there.
“One of the most difficult decisions that oil spill responders and natural resource managers face during a spill is evaluating the trade-offs associated with dispersant use,” said the Academy report, titled Oil Spill Dispersants, Efficacy and Effects.“There is insufficient understanding of the fate of dispersed oil in aquatic ecosystems.”
Sylvia Earle, the National Geographic’s explorer-in-residence and former chief scientist at NOAA, stated that “the instructions for humans using Corexit warn that it is an eye and skin irritant, is harmful by inhalation, in contact with skin and if swallowed, and may cause injury to red blood cells, kidney or the liver.”“People are warned not to take Corexit internally,” she said,“but the fish, turtles, copepods and jellies have no choice. They are awash in a lethal brew of oil and butoxyethanol.”
Earle further states,“Not only is the flow of millions of gallons of oil an issue in the Gulf, but also the thousands of gallons of toxic dispersants that make the ocean look a little better on the surface – where most people are – but make circumstances a lot worse under the surface, where most of the life in the ocean actually is. We don’t know what the effect of dispersants applied a mile underwater is; there’s been no laboratory testing of that at all, or the effect of what it does when it combines with oil a mile underwater.” One problem with breaking down the oil is that it makes it easier for the many tiny underwater organisms to ingest this toxic soup.
Earle called for a halt on the subsurface use of dispersants, while limiting surface use to strategic sites where other methods cannot safeguard critically important coastal habitats.
For a better understanding of why toxic dispersants are being used by BP in such an excessive and unprecedented manner, visit: http://renergie.wordpress.com/2010/07/12/bps-...