Toxins From Oil Spills Are Putting Fish Into Cardiac Arrest, Study Finds

CREDIT: AP Photo/Charlie Riedel

A small oil-covered fish lies on the water's surface at Bay Long off the coast of Louisiana Sunday, June 6, 2010.

For marine life, this Valentine’s Day is shaping up to be less about love, and more about heartache.

Attempting to draw attention to marine animals exposed to the tragic Deepwater Horizon oil spill in 2010, scientists from both Stanford University and the National Oceanic and Atmospheric Administration (NOAA) released a study on Friday showing that oil spills are causing death-by-cardiac arrest in tunas and other types of fish.

The study, published in Science Magazine, says chemicals in crude oil — such as polyaromatic hydrocarbons (PAHs) — can be harmful to the hearts of embryonic and developing fish. PAHs are created when products like coal, oil, gas, and garbage are burned but the burning process is not complete, according to the EPA. Even after an oil spill occurs and is cleaned up, PAHs can remain marine habitats for many years, according to the study.

The PAHs in the oil block key processes in living organisms’ cardiac cells, Barbara Block, a professor of marine sciences at Stanford, told BBC News. Blocking key processes like the moving of potassium and calcium ions move in and out of cells can cause a slowing of the heart, irregularities in rhythm and even cardiac arrest at high exposures, the study said.

“The ability of a heart cell to beat depends on its capacity to move essential ions like potassium and calcium into and out of the cells quickly,” Block said. “We have discovered that crude oil interferes with this vital signalling process essential for our heart cells to function properly.”

As the BBC reported, this also means that any other animal that swam in waters around the Deepwater Horizon rig — including humans — would have been exposed to similar cardiac risks.

In order to come to its results, the scientists at Stanford and NOAA took in vitro preparations of living cardiac cells taken from the hearts of tuna, and bathed those cells in crude oil at a level similar to what fish in early life stages may have encountered after the oil spill. The scientists then recorded disruptions in cells’ signaling pathways, and applied the results to any other fish that would have been swimming near the rig — dolphin fish, blue marlin and swordfish, to name a few.

BP has taken issue with the study’s process, however, saying it failed to show that the blowout of its rig has harmed marine life.

“The paper provides no evidence to suggest a population-level impact on tuna or other fish species in the Gulf of Mexico,” BP spokesman Jason Ryan told the LA Times. “Bathing isolated heart cells with oil concentrations is simply not comparable to the real-world conditions and exposures that existed in the gulf for whole fish.”

This, however, is not the first time the Deepwater Horizon oil spill has been linked to abnormalities in marine life. Dolphins living in an area hit hard by the spill are now suffering from lung damage and hormonal levels that are lower than in any other recorded dolphin population, a study from NOAA found in December. Dolphins from Barataria Bay were five times more likely than Sarasota Bay dolphins to have moderate–severe lung disease, and nearly half of them had low levels of adrenal gland hormones, that study said.

“I’ve never seen such a high prevalence of very sick animals — and with unusual conditions such as adrenal hormone abnormalities,” Lori Schwacke, the lead author of the study, told the Times-Picayune.

A 2012 study also found that a die-off of young dolphins off the Gulf Coast between January 1 and April 30 2011 was linked to oil exposure. And one study found Gulf killifish — an environmental indicator species — exposed to the spill had higher rates of developmental abnormalities compared to fish who weren’t.