Dispersant Used to Fight Deepwater Horizon More Toxic to Coral Than Oil

By Jamie Condliffe on at

It's almost five years since Deepwater Horizon went belly up.Research now suggests that a substance used to clear up the site of the spill is more toxic to cold water corals than the oil itself.

In research carried out by scientists from Temple University and the Pennsylvania State University, it was found that cold-water coral species from the Gulf declined in health when exposed to a particular dispersant, which is used with the intention to break up the pools of oil into smaller droplets. In fact, lower concentrations of the dispersant were required to bring about ill health than the concentrations of oil required to do so. The results are published in Deep-Sea Research II.

Around five million barrels of crude oil escaped during the Deepwater Horizon disaster, which were fought off using seven million litres of dispersant. Usually these chemicals, which break down the thick expanses of oil, are used on the surface—but in the case of Deepwater Horizon they were pumped down into the ocean to break up the oil as soon as it appeared at the sea floor.

That means that the dispersant-oil mix drifted through the ocean and it wasn't known what effects the initiative would have. "Applying the dispersants at depth was a grand experiment being conducted in real-time," explains Erik Cordes, one of the researchers, to PhysOrg. "It was a desire to immediately do something about the oil coming out of the well, but they really didn't know what was going to happen as a result."

The researchers will continue to investigate the effects of the clean-up operation of Deepwater Horizon on ocean life. But hopefully these findings will help ensure that similar future events are treated as effectively as possible. [Deep-Sea Research II via PhysOrg]