LSU study: Damaged minnow shows BP oil seeping into coastal food chain
The Lens–LSU study: Damaged minnow shows BP oil seeping into coastal food chain
By Bob Marshall, Staff writer April 30, 2013 11:45am
A minnow considered the canary in Louisiana’s coastal ecosystem can’t shake the hydrocarbon cough it picked up when BPs oil started washing ashore three years ago.
Recent studies on new generations of the Gulf killifish, a marsh minnow diagnosed with signs of oil poisoning in 2010, shortly after the Macondo blowout began, confirm that hydrocarbon toxins remain in marsh sediments and continue to cause biological impairments that were precursors for species-wide collapses in Alaska after the Exxon Valdez spill.
The results have no implication for seafood safety because the levels of toxins detected are well below those considered hazardous for seafood consumption, the researchers said.
While the killifish is best known locally as the “cocahoe minnow,” a bait fish favored by anglers, researchers consider it the equivalent of the proverbial canary in a coal mine, a keystone species in the food chain that can give early warnings of problems for the entire system.
Andrew Whitehead, who in 2010 led an LSU team studying adult killifish from heavily oiled areas of Barataria Bay, said at the time, “We were detecting cellular responses to toxins that are predictive of impairment of reproduction and embryo development.”
Now, follow-up lab research on killifish embryo have confirmed those fears.
“They had the same hallmark signature impacts of cardiovascular toxicity as the adults. There was an accumulation of fluid around the heart, depressed heart rates and decreased hatching success.” – Andrew Whitehead
The research team exposed one group of embryo to sediments collected from heavily oiled areas of the bay and another group to sediments from areas that were not impacted.
“We know that early life stages, especially in fish, are very sensitive to the effects of oil, and we know that many animals (in the Gulf ) use these estuaries for the early stages of life and will be exposed to these sediments,” Whitehead said. “So we wanted to bring the research into the lab with a control group to see what the results would be, especially more than a year later.”
The embryos exposed to uncontaminated sediments showed no abnormalities, but those exposed to the oil-impacted sediments displayed many of the same developmental impairments detected in the adult fish during the first project, researchers found.
“They had the same hallmark signature impacts of cardiovascular toxicity as the adults,” Whitehead said. “There was an accumulation of fluid around the heart, depressed heart rates and decreased hatching success.”
The researchers were looking for signs that the embryos were impacted by polycyclic aromatic hydrocarbons (PAHs), components of oil that are known carcinogens and that can persist for more than 50 years in ecosystems hit by oil spills. As in the first study, the levels recorded in this project were either trace or “undetectable” – the term used when a toxin does not register in water samples but animals exhibit biological responses that are symptomatic of exposure.
The responses shown by killifish embryos to such low levels of PAHs reinforced concern that trouble could be waiting down the line for economically more valuable species.
Whitehead, now at the University of California at Davis, said the concern wasn’t about the toxins accumulating in predators such as speckled trout and redfish that consume killifish, but that long-lasting PAHs could have biological impacts that may show up in future generations of a whole range of creatures that live close to and on the marsh bottom, such as shrimp, crabs and oysters.
“A lot of the (PAHs) have sunk into sediments in the marshes in Barataria Bay and get redistributed into the water column every time it gets windy,” he said. “So all animals that use shallow water in these estuaries will be exposed.”
A cause for hope, he said, is that only a handful of places across the vast Louisiana coast were heavily hit by the oil. That could mean large populations of killifish and other species were unaffected.
“So the hope would be animals that inhabit areas that were not heavily hit will be able to provide unaffected populations that can buffer the harm done in the affected area,” Whitehead said.
“Of course, we don’t know that, and that’s why we need to continue to monitor this.”
Whitehead repeated a concern voiced in 2010 that enough research should be done on the biology of the species being examined rather than just their safety for human consumption.
“As these studies show, you can have levels of these toxins that are no threat to humans, but can cause serious problems for a whole range of animals living in the ecosystem with just a very small level of contamination,” Whitehead said. “I haven’t seen a whole lot of research published on the biology of animals post-spill. That concerns me.”
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ABOUT BOB MARSHALL
More from this author
Bob Marshall covers environmental issues for The Lens, with a special focus on coastal restoration and wetlands. While at The Times-Picayune, his work chronicling the people, stories and issues of Louisiana’s wetlands was recognized with two Pulitzer Prizes and other awards. In 2012 Marshall was a member of the inaugural class inducted into the Loyola University School of Communications Den of Distinction. He can be reached at (504) 232-5013.
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http://www.huffingtonpost.com/2013/04/25/corexit-bp-oil-dispersant_n_3157080.html?utm_hp_ref=green
Huffington Post: Corexit, Oil Dispersant Used By BP, Is Destroying Gulf Marine Life, Scientists Say
Posted: 04/25/2013 5:02 pm EDT | Updated: 04/25/2013 5:20 pm EDT
From TakePart’s David Kirby:
Three years ago, when BP’s Deepwater Horizon began leaking some 210 million gallons of Louisiana Crude into the Gulf of Mexico, the U.S. government allowed the company to apply chemical “dispersants” to the blossoming oil slick to prevent toxic gunk from reaching the fragile bays, beaches, and mangroves of the coast, where so much marine life originates. But a number of recent studies show that BP and the feds may have made a huge mistake, for which everything from microscopic organisms to bottlenose dolphins are now paying the highest price.
After the spill, BP secured about a third of the world’s supply of dispersants, namely Corexit 9500 and 9527, according to The New York Times. Of the two, 9527 is more toxic. Corexit dispersants emulsify oil into tiny beads, causing them to sink toward the bottom. Wave action and wind turbulence degrade the oil further, and evaporation concentrates the toxins in the oil-Corexit mixture, including dangerous compounds called polycyclic aromatic hydrocarbons (PAHs), known to cause cancer and developmental disorders.
When BP began spraying the Gulf, critics cried foul. They said Corexit is not only toxic to marine life on its own, but when combined with crude oil, the mixture becomes several times more toxic than oil or dispersant alone.
Not surprisingly, BP Chief Executive Bob Dudley defended use of the dispersant. “The toxicity of Corexit is about the same as dish soap, which is effectively what it is and how it works,” he told stockholders. “In hindsight no one believes that that was the wrong thing and it would have been much worse without the use of it. I do not believe anybody-anybody with almost common sense-would say waves of black oil washing into the marshes and beaches would have been a better thing, under any circumstances.”
BP says that Corexit is harmless to marine life, while the Environmental Protection Agency has waffled, saying both that “long term effects [of dispersants] on aquatic life are unknown” and that data “do not indicate any significant effects on aquatic life. Moreover, decreased size of the oil droplets is a good indication that, so far, the dispersant is effective.”
But many scientists, such as Dr. William Sawyer, a Louisiana toxicologist, argue that Corexit can be deadly to people and sea creatures alike. “Corexit components are also known as deodorized kerosene,” Sawyer said in a written statement for the Gulf Oil Disaster Recovery Group, a legal consortium representing environmental groups and individuals affected by the Deepwater Horizon spill. “With respect to marine toxicity and potential human health risks, studies of kerosene exposures strongly indicate potential health risks to volunteers, workers, sea turtles, dolphins, breathing reptiles and all species which need to surface for air exchanges, as well as birds and all other mammals.” When Corexit mixes with and breaks down crude, it makes the oil far more “bioavailable” to plants and animals, critics allege, because it is more easily absorbed in its emulsified state.
Sawyer tested edible fish and shellfish from the Gulf for absorption of petroleum hydrocarbon (PHC), believed to have been facilitated by Corexit. Tissue samples taken prior to the accident had no measurable PHC. But after the oil spill, Sawyer found tissue concentrations up to 10,000 parts per million, or 1 percent of the total. The study, he said, “shows that the absorption [of the oil] was enhanced by the Corexit.”
In April 2012, Louisiana State University’s Department of Oceanography and Coastal Sciences was finding lesions and grotesque deformities in sea life-including millions of shrimp with no eyes and crabs without eyes or claws-possibly linked to oil and dispersants.
The shocking story was ignored by major U.S. media, but covered in depth by Al Jazeera. BP said such deformities were “common” in aquatic life in the Gulf and caused by bacteria or parasites. But further studies point back to the spill.
A just-released study from the University of South Florida found that underwater plumes of BP oil, dispersed by Corexit, had produced a “massive die-off” of foraminifera, microscopic organisms at the base of the food chain. Other studies show that, as a result of oil and dispersants, plankton have either been killed or have absorbed PAHs before being consumed by other sea creatures.
Hydrocarbon-laden, mutated seafood is not the only legacy left behind by Corexit, many scientists, physicians, environmentalists, fishermen, and Gulf Coast residents contend. Earlier this week, TakePart wrote about Steve Kolian, a researcher and founder of the nonprofit group EcoRigs, whose volunteer scientists and divers seek to preserve offshore oil and gas platforms after production stops, for use as artificial reefs and for alternative energy production.
EcoRigs divers took water and marine life samples at several locations in the months following the blowout. Now, they and countless other Gulf residents are sick, with symptoms resembling something from a sci-fi horror film, including bleeding from the nose, ears, breasts, and even anus. Others complain of cognitive damage, including what one man calls getting “stuck stupid,” when he temporarily cannot move or speak, but can still hear.
“If we are getting sick, then you know the marine life out in the Gulf is too,” Kolian said. The diver and researcher completed an affidavit on human and marine health used in GAP’s report.
Kolian’s team has done studies of their own to alarming results. “We recently submitted a paper showing levels of hydrocarbons in seafood were up to 3,000 times higher than safety thresholds for human consumption,” he said. “Concentrations in biota [i.e. all marine life] samples were even greater.”
Kolian’s friend and colleague, Scott Porter, described in his affidavit to GAP how Corexit had caused dispersed crude to coat the bottom of the sea in a sickening, deadly film. In July 2011, he and other divers traveled to a part of the Florida Panhandle, known as the Emerald Coast for its pristine seawater, to collect samples for the Surfrider Foundation.
“When we went diving, however, the water had a brownish white haze that resembled what we saw in offshore Louisiana at 30 feet below sea level,” Porter’s affidavit stated. “I have never witnessed anything like that since I began diving in the Emerald Coast 20 years ago. We witnessedŠa reddish brown substance on the seafloor that resembled tar and spanned a much larger area than is typical of natural runoff.”
In areas covered with the substance, “we noticed much less sea life,” Porter continued. “There were hardly any sand dollars or crabs and only some fish, whereas we would normally see an abundance of organisms. It was desolate.”
Special thanks to Richard Charter
