http://blog.al.com/live/2012/07/levels_of_deadly_bacteria_more.html
Published: Friday, July 27, 2012, 3:59 PM Updated: Friday, July 27, 2012, 4:52 PM
By Ben Raines, Press-Register
2010, the year of the BP oil spill ranked among the worst years on record for deaths related to the consumption of oysters tainted with the Vibrio vulnificus bacteria, though the Gulf harvest was down by about 40 percent. The deadly bacteria typically increases in abundance during the warmest parts of the year in the Gulf. In 2010, apparently fueled by the oil floating in the Gulf, vibrio levels were more than 100 times higher than previous years in seawater and sediments. (Ben Raines/Press-Register)
Although the Gulf’s oyster harvest was off by about 40 percent due to fishing closures stemming from the BP oil spill, 2010 ranks as one of the deadliest years on record for illnesses caused by eating oysters tainted with Vibrio vulnificus.
A new analysis by the Press-Register of scientific papers suggests that the deadly bacteria was hundreds of times more abundant in the Gulf in the months during and after the BP oil spill than in previous years.
The newspaper shared its findings with scientists and the U.S. Food & Drug Administration. Agency officials agreed that the bacteria levels in Gulf seawater and sediments were elevated during and after the spill and said that may have translated into an increased risk of infection for people eating oysters.
“They are elevated upwards of 100 fold or more. We see that and acknowledge it,” said Bob Dickey, director of the FDA’s Gulf Coast Seafood Laboratory on Dauphin Island.
Given that 38 people were sickened and 16 of those died after eating oysters in 2010, despite the limited harvest, Dickey said it appeared that there were more deaths per pound of oysters consumed than has been seen in the past.
“That does appear to be the case. The risk might have increased during 2010 when you look at it that way and do your division. We can’t deny that,” Dickey said.
In a written statement, BP officials noted that vibrio bacteria are commonly found in the Gulf, and stated “The CDC estimates that the average annual incident of all Vibrio infections increased by 41 percent between 1996 and 2005, a time frame that predates the Deepwater Horizon incident.” The company also suggested that conditions in the Gulf are steadily returning to normal.
Vibrio vulnificus is a waterborne bacteria related to cholera. It typically infects dozens of people a year, killing 10 to 20, with 301 deaths since 1989, according to federal statistics. Oysters from the Gulf are implicated in the vast majority of the cases. There were 27 cases with 14 deaths in 2011, Dickey said, a notable drop compared to 2010.
Vibrio blooms in the Gulf in the warmest months of the year, with nearly all cases of human illness occurring between April and September. In the winter months, Gulf oysters are essentially free of the bacteria, leading to the old saw about only consuming oysters in months that have an “R” in them.
The bacteria is killed by heat, so it is not a threat in cooked seafood, including cooked oysters. It can be present in the intestines of fish, but is not typically associated with raw fish eaten as sushi as it does not occur in the flesh of the fish.
Since 1989, there have been only two years – 1998 and 2001 – with as many deaths and illnesses related to oyster consumption as there were in 2010. The big difference between those years and 2010 is that people ate a lot fewer Gulf oysters the year of the BP oil spill.
In 2005, when the Gulf’s oyster production was limited because of Hurricanes Katrina and Rita, there were 12 vibrio cases nationwide, with six deaths, according to statistics from the Centers for Disease Control and Prevention.
Scientists said the high number of vibrio cases in 2010 was unexpected and counterintuitive. That’s where the higher number of vibrio bacteria in the water column and in seafloor sediments during the oil spill may come into play.
A paper by Auburn University’s Cova Arias that documented exceptionally high levels of vibrio bacteria in tarballs caused quite a stir when it was published last November, raising concern that tarballs might pose a danger to cleanup crews and beachgoers.
While the levels of vibrio that she recorded in the sediment and seawater escaped widespread notice at the time, they, too, were significant. The Press-Register’s recent analysis of the same data found that the levels seen along the Alabama and Mississippi coasts during the spill were sometimes hundreds of times higher than levels measured by federal scientists in 1994, 2006 and 2007.
For instance, Arias measured 8,300 vibrio bacteria per milliliter of seawater in Gulf Shores in October 2010. Nearly all of the levels in previous federal studies examined by the newspaper were below 100 bacteria per milliliter.
Arias measured 160,000 vibrio bacteria per gram of sediment in Gulfport in June 2010, shortly after the BP oil began washing ashore. The highest level recorded in any of the earlier federal studies was about 10,000 vibrio bacteria per gram, and most of the sampling events recorded much lower levels.
The newspaper shared its findings with Arias and scientists from federal agencies, the Dauphin Island Sea Lab, the University of South Alabama and the University of Southern Mississippi.
“A bad vibrio year could be attributed to the massive amount of carbon injected into the region about 2? years ago,” said George Crozier, the retired director of the Dauphin Island Sea Lab, referring to the oil spill.
Crozier said the oil in the Gulf amounted to “a prime feeding frenzy” for microbes like vibrio, which consume hydrocarbons like “a pack of hyenas on an elephant carcass.” He said the bacteria multiplied due to the massive food source and were part of an overall bloom of bacteria that helped clean up the oil.
David Plunkett focuses on vibrio in oysters for the Washington, D.C.-based Center for Science in the Public Interest. His organization has filed legal challenges against the FDA, trying to force the agency to keep vibrio-tainted oysters out of the nation’s food supply. Vibrio is the leading cause of seafood-related deaths and illnesses.
“With the oil spill, they started shutting down the oyster beds. One of the comments was, ‘We’ll probably have fewer vibrio cases,'” Plunkett said.
The fact that there were so many cases “was surprising,” he said. “If you did have a higher number of vibrios in the water, then the oysters might have had a higher number.”
Arias said her group did not examine oyster tissue for the presence of vibrio, only tarballs, sand and seawater. She said the fact that her group sampled in only five locations made it difficult to draw conclusions based on the data. Her research is ongoing.
Federal landings data on the Gulf oyster harvest show that there were more cases of vibrio per pound of oysters eaten in 2010 than in previous years.
Between 1995 and 2010, the most recent year for which federal oyster landings records are available, the Gulf harvest averaged 24 million pounds. In 2010, the harvest totaled just 15 million pounds, yet vibrio cases were on par with the worst years on record.
Dickey stressed that most people who become infected or die after consuming vibrio in oysters have compromised immune systems, a fact borne out in the CDC data.
“I think that FDA’s longstanding guidance to the public that persons with weakened immune systems or compromised health in any way should avoid eating raw oysters because of their susceptibility to infection is important,” Dickey said.
“It is important to realize we are working very closely with the industry to reduce this risk.”
Some people contract vibrio infections by swimming with open wounds, or after being punctured by fish fins. Dickey said that his agency couldn’t assess the risks posed by swimming or other activities during or after the oil spill.
“Vibrio vulnificus is one of the most abundant bacteria in our coastal environment. People who swim in the water are exposed to them all the time,” Dickey said. “What these (scientists) have found is that it was elevated beyond what we normally would see. We can’t assess the environmental exposures. We’re dealing with seafood.”
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Updated at 4:50 p.m. to add links to resources from the Food & Drug Administration.
Special thanks to Richard Charter
http://fisheriestoday.blogspot.ca/2012/08/bp-oil-spill-dispersants-may-have-hurt.html
Fisheries Today
August 1, 2012
BP oil spill dispersants may have hurt Gulf of Mexico food chain, study finds
A study on possible effects of the 2010 BP oil spill indicates dispersants may have killed plankton — some of the ocean’s tiniest plants and creatures — and disrupted the food chain in the Gulf of Mexico, one of the nation’s richest seafood grounds. Scientists who read the study said it points toward major future effects of the spill. One called its findings scary.
For the study, Alabama researchers pumped water from Mobile Bay into 53-gallon drums, then added oil, dispersant or both in proportions found during the oil spill to simulate the spill’s effects on microscopic water-life in the bay.
Over more than 12 weeks in 2010, BP’s well spewed nearly 200 million gallons of oil into the Gulf of Mexico. The company used more than 1.8 million gallons of dispersants — more than 770,000 gallons of it at the oil’s source on the ocean floor — to break up the oil into tiny droplets. Earlier research hadn’t found significant problems for the environment and marine life, but dispersants had never before been used a mile underwater or in such large amounts.
The researchers found that, within days, the numbers of plant-like phytoplankton and ciliates — plankton that use hairlike cilia to move — increased under an oil slick. But they dropped significantly in the drums with dispersant or dispersed oil, while the numbers of bacteria increased. The study was published Tuesday in PLoS ONE, one of the peer-reviewed journals in the online Public Library of Science.
“In those tanks, all of the energy seems to get trapped in the bacterial side. There were lots of bacteria left but no bigger things. It’s like the middle part of the food web is taken away,” said lead researcher Alice Ortmann of the University of South Alabama and Dauphin Island Sea Lab.
Microbes are too small for fish to eat. Ciliates, on the other hand, “graze” on microbes. Phytoplankton and cilates both get eaten by larger zooplankton, which are fodder for tiny crustaceans that, in turn, get eaten by small fish.
Brian Crother, a biology professor at Southeastern Louisiana University, called the findings scary, though limited because the experiments spanned only five days. “If these guys are on the money, they have pointed to something really disastrous happening in the Gulf,” he said.
The study was extremely well done, said Michael Crosby, senior vice president for research at Mote Marine Laboratory in Sarasota, Fla. “You’ve got to look at the impact on the ecosystem as a whole, rather than individual species,” he said.
It is also, he said, more evidence for what he has thought all along: that the Gulf of Mexico’s food web is in danger. “If you go a couple steps beyond their findings, I think we’re going to see these things happening and it’s going to take years for them to be seen,” he said.
Ortmann said she and her colleagues, including scientists at Auburn University, were surprised that dispersant alone had such a big effect on plankton.
Carbon is a basic part of most life on earth, and an earlier study at Dauphin Island Sea Lab found that plankton quickly gulped down oil from the spill.
Crother said the new study makes clear that the damage to plankton was from dispersant, not oil. “These guys have shown … that the carbon available from that dispersant is not easily utilized for energy at the bottom of the food chain,” he said.
Still, other research indicates that “fish did very well in 2010,” Ortmann said. There’s no indication that the food web was completely disrupted, but it might have been interrupted in certain areas, she said.
More research is being done to try to understand the spill’s actual impact, she said.
Crosby noted that some environmental effects weren’t seen for years after the tanker Exxon Valdez hit a reef and broke open off Alaska in 1989, causing what was then the nation’s largest spill, 11 million gallons.
The late 1980s had been marked by record commercial harvests of herring, but by 1993, the number of spawning adults had dropped by three-quarters. Disease, ocean changes, contaminants, competition from other fish and increasing numbers of humpback whales are being studied as possible reasons that the species has never recovered.
“The herring population in Prince William Sound didn’t collapse until four years after the Exxon Valdez,” Crosby said. “It has never recovered. Never.”
Janet McConnaughey of The Associated Press wrote this report.
View full sizeBP PLC, via The Associated PressAn image from video made available by BP PLC shows dispersant being applied to an oil leak during efforts to cap the Deepwater Horizon oil well in the Gulf of Mexico on June 3, 2010. The white wand in the center is releasing the dispersant.
Special thanks to Richard Charter