Study Finds Strong Connection Between Deepwater Horizon Spill and Dolphin Deaths
A dolphin swims by as workers collect tar balls deposited on a beach in Grand Isle, La., following the 2010 Deepwater Horizon accident.
Dolphins in an area hard hit by the Gulf of Mexico oil spill in 2010 are suffering from lung diseases and other abnormalities that are consistent with toxic exposure to oil, according to a study backed by the federal government and released on Wednesday.
The peer-reviewed paper, which was disputed by BP BP.LN +1.65% PLC, was published in the journal Environmental Science & Technology. The paper makes the strongest connection to date between the BP spill and dolphin deaths, which jumped in the Gulf of Mexico after the spill.
"It is related to oil," said Lori Schwacke, the study's lead author and a wildlife epidemiologist at the National Oceanic and Atmospheric Administration. "The weight of evidence is there."
BP, which paid for the study, disputes that it shows a clear link between the spill and dolphin illnesses. NOAA "still hasn't provided BP with any data demonstrating that the alleged poor health of any dolphins was caused by oil exposure," said BP spokesman Jason Ryan in an email.
The study was released the same morning a federal jury in New Orleans convicted an engineer who worked for BP in 2010 of destroying evidence about the oil spill. Prosecutors argued that the engineer, Kurt Mix, deleted hundreds of text messages to try to hide evidence that the company knew more oil was leaking than it had revealed publicly.
Mr. Mix was found guilty of one count of obstruction of justice but acquitted on a second count. The count carries a maximum sentence of 20 years in prison and a $250,000 fine, but his lawyer said he would appeal.
For the dolphin study, scientists caught, examined and released about 30 bottlenose dolphins in Barataria Bay, La., in 2011. Moderate to severe lung diseases associated with oil contamination were prevalent among many of the dolphins, and almost half had "a guarded or worse prognosis, and 17% were considered poor or grave, indicating they weren't expected to live," according to the study. Dolphins in the area likely will have more difficulty reproducing, the study found.
The scientists also looked at dolphins in Sarasota Bay, Fla., as a control, because that area wasn't hurt by the oil spill. The study didn't find elevated lung diseases in that population.
"Finally, we get the truth," said Casi Callaway, executive director of Mobile Baykeeper, an environmental group on Alabama's coast. "Having this information gets us started on the path toward a solution, toward fixing what has been broken for 3½ years."
If top ocean predators like dolphins are suffering, scientists must learn how the spill has affected other animals, including "smaller sea creatures, and larger life, even humans," she said.
BP said the study failed to make a connection between the spill and sick dolphins. "The symptoms that NOAA has observed in this study have been seen in other dolphin mortality events that have been related to contaminants and conditions found in the northern Gulf, such as PCBs, DDT and pesticides, unusual cold stun events, and toxins from harmful algal blooms," Mr. Ryan said in his email.
In April 2010, an explosion erupted on the Deepwater Horizon drilling rig about 40 miles off the Louisiana coast, after a blowout of the BP-owned well 5,000 feet below the ocean surface. Over 87 days, oil slicks spread across open water and fouled more than 1,000 miles of coastline. About 4.2 million barrels of oil spilled into the Gulf, according to official estimates, although BP argues it was closer to 2.45 million barrels. It was the worst offshore oil spill in U.S. history.
The dolphin study was done as part of a process led by NOAA called a Natural Resource Damage Assessment. If studies find a link between the spill and any damage, BP would be expected to pay compensation, though the company can appeal findings in court.
Though BP paid for the study, it wasn't involved in the analysis.
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