It has long been suspected that the 2010 BP oil spill was the reason that dolphins in the Gulf of Mexico died. For the first time, U.S. scientists from the National Oceanic and Atmospheric Administration (NOAA) have confirmed that the oil spill directly caused the deaths of dolphins. Dolphins in Barataria Bay, Louisiana have been found to be suffering from lung disease, hormonal abnormalities and other health effects that are consistent with exposure to oil.
Barataria Bay was subjected to “heavy and prolonged oiling” after BP’s drilling platform exploded, killing 11 workers and spewing millions of barrels of crude oil into the Gulf. In the months after the spill, a pronounced spike in dolphin strandings and deaths was noted.
For a study published in the journal Environmental Science and Technology, NOAA scientists compared dolphins in Barataria Bay to those in Sarasota Bay, Florida, where oil was not observed. 29 dolphins from Barataria Bay were evaluated and showed signs of “uncommon” diseases that are “consistent with petroleum hydrocarbon exposure and toxicity,” say the scientists. In particular, the dolphins showed signs of hypoadrenocorticism (low adrenal levels — adrenal hormones are critical to respond to stress) that are “consistent with adrenal toxicity as previously reported for laboratory mammals exposed to oil.” They were also found to be five times more likely to have moderate to severe lung disease, such that their ability to breathe has been impaired.
Not only were the Barataria Bay dolphins far more likely to be sick than the Sarasota Bay dolphins, they were also more likely to have health problems that were far more severe. The disease conditions in the Barataria Bay dolphins were far more prevalent and severe than “previously reported in other wild dolphin populations,” period.
To say that the prognosis for the Barataria Bay dolphins is poor is an understatement. Of the 29 dolphins evaluated Bay, 48 percent were given a “guarded or worse prognosis” and 17 were found to be “poor or grave, indicating that they were not expected to survive.”
As lead author Lori Schwake said in a statement, “I’ve never seen such a high prevalence of very sick animals — and with unusual conditions such as the adrenal hormone abnormalities.”
“After the spill I saw dolphins swimming in and out of oil slicks, breathing air at the surface that I knew contained hydrocarbons from the spill since I could smell them myself. The dolphins were likely exposed to the oil in other ways as well, by swallowing water, and through their food. While we have seen an unusual number of dolphin deaths during and after the spill, this report verifies that the oil took a larger toll on dolphins.”
Since the disaster, BP has stringently disputed that the massive oiling of the Gulf was the reason for the illnesses and deaths of dolphins and claimed that other contaminants were the culprit. In their study, the NOAA researchers actually examined alternative hypotheses for the dolphins’ disease conditions, including exposure to other human-made chemicals which had been previously found in high concentrations in dolphins and other marine mammals and been linked to effects on their health. Blubber samples from the Barataria Bay dolphins only showed “relatively low concentrations for the broad suite of chemicals measured, including PCBs and commonly detected persistent pesticides,” in comparison to other dolphin populations.
The health problems seen in the Barataria Bay dolphins also mean that their ability to reproduce has been diminished. The new NOAA study makes too clear that the BP oil spill was and continues to be an unmitigated disaster for marine wildlife — whales, sea birds and countless other animals — in the Gulf of Mexico and why, frankly, no matter how cheap gas at a BP filling station is, I prefer to drive past and seek out a different one.
Photo via Thinkstock
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