Some of the most important lingering questions on BP’s oil spill concern the effectiveness and long-term impact of chemical dispersants used during the disaster – points of great contention between the oil industry and environmentalists.
BP PLC, via The Associated PressUnderwater application of dispersant is seen in this image taken from video on June 3, 2010.
It’s not surprising, then, that both supporters and critics of dispersants are seeking to draw hard conclusions from a new scientific study that found a key dispersant component still present within a deepwater plume months after the Macondo well was capped.
Gulf residents, however, should look past the talking points from advocacy groups to ascertain the study’s most significant conclusion: that further research is needed to determine whether dispersants are the most effective tool in deepwater spills and what harm they may cause to marine life.
Scientists from the Woods Hole Oceanographic Institute in Rhode Island and from two California universities sampled Gulf water after the spill to track a chemical that’s part of Corexit 9500A, the dispersant used at the wellhead to break up the oil into tiny droplets. BP used about 770,000 gallons of Corexit at the sea floor.
The scientists found the chemical in the plume between 3,000 and 3,600 feet below the ocean’s surface and tracked it over a two-month period over a 200-mile path southwest from the well. They concluded the chemical mixed with water but had not biodegraded. That contradicts assurances by BP and Corexit officials that the dispersant biodegraded quickly, as soon as a few days in some cases.
Environmentalists are seizing on the finding to argue against using dispersants. But the study’s lead scientist, Elizabeth Kujawinsky, cautioned that “we can’t be alarmist” about the implications of her team’s findings – and she’s right. She noted that the concentrations of the chemical they detected in the Gulf were 1,000 times smaller than what is considered toxic. By the same token, those standards of toxicity are not formulated for fish and other organisms that live deep under water.
But this research is an important building block for other scientists, including those at the EPA and other federal agencies, working to evaluate the toxicity of dispersants. It’s impossible to make an informed judgement on dispersants without knowing the result of that ongoing work.
Indeed, the national oil spill commission called for further research on dispersants, including on the impact of using a high volume of the chemicals and of using them in deepwater. The commission also recommended that the EPA update its dispersant testing protocols to require more tests before listing or pre-approving a particular dispersant. These are needed steps.
As University of California Santa Barbara professor David Valentine said, “The decision to use chemical dispersants at the sea floor was a classic choice between bad and worse.”
Preventing future spills and having better response technology is the best way to avoid such a choice again. But scientists still would need to know whether dispersants are a valid alternative and at what cost for the environment.