Chemical oil dispersants BP used in 2010 to break up its Deepwater Horizon oil spill are still turning up in samples collected from the Gulf’s beaches and deep sea corals, a new scientific study has found.
Scientists studying the presence the dispersant chemical DOSS (dioctyl sodium sulfosuccinate) in the Gulf of Mexico environment expected to see a slower degradation in the deeper, colder areas of the Gulf, but the lingering presence of the chemical along the shore came as a surprise.
The study, conducted by scientists from Haverford College and Woods Hole Oceanographic Institution and published in the journal Environmental Science & Technology Letters, doesn’t examine the possible effects the chemicals may be having on the Gulf environment, but emphasizes that it’s important for researchers still studying the fallout from BP’s massive oil spill to know the chemicals are still there.
“These results indicated that the dispersant, which was thought to undergo rapid degradation in the water column, remains associated with oil in the environment and can persist for around four years,” said Helen White, assistant professor of chemistry at Haverford College and lead author of the study.
“The interesting thing is that the sand patties we’re finding on beaches four years after the spill have DOSS in them. That was somewhat unexpected,” co-author Elizabeth Kujawinski of Woods Hole added, explaining that the chemical was found in samples weathered by years of wave action, temperature fluctuations, and air.
BP dumped about 1.8 million gallons of the dispersant Corexit into the Gulf between April 22 and July 19, 2010, in an effort to break up the spill, which released an estimated 208 million gallons of oil into the Gulf before it was stopped months later in August. Environmental scientists harshly criticized the oil giant for using large quantities of the chemicals in unprecedented, unstudied ways, especially when BP workers injected dispersants into the oil at the wellhead a mile beneath the surface – a treatment that created massive plumes of toxic oil particles that stretched throughout the Gulf for miles.
BP denies the chemicals came from its “cleanup” campaign and says that whatever their source, the dispersants don’t present a risk to human health or marine life.
Scientists who actually study the relationship between oil dispersants and the environment are less certain. Previous studies have uncovered links between the chemicals and diseased fish populations and the authors of this latest study say they don’t know how toxic DOSS is.
“The purpose of the paper was really to let researchers and policy makers know these components are still in the sand patties but they are at levels where we don’t know the health effects,” Dr. Kujawinski said. “We don’t know if sand laced with this molecule is harmful.”
Sava Varazo, a water quality scientist and director of Emerald Coastkeepers, told the Pensacola News Journal that the dispersants are likely still taking on a toll on both humans and sea life.
“I compare this to what happened in the (1989 Exxon) Valdez spill in Alaska’s Prince William Sound,” Varazo told the Pensacola News Journal. “Four years later, the herring population was decimated because of these same issues. We have four years behind us. We have lots of studies saying lots of things. We’re starting to see the long-range impacts.”
Keith Wilkins, Escambia County’s director of community and environment, told the Pensacola News Journal that the study underscores the importance of being conservative in the use of any chemicals, be they prescription drugs or oil dispersants, simply because they never break down in the environment but accumulate.
“People think things go away and they don’t,” Mr. Wilkins told the Pensacola News Journal.” All the chemicals we use every day and all of the pharmaceuticals we use don’t disappear. They dilute but don’t go away.”