Oil from the Deepwater Horizon disaster are STILL present, study says

Jonathan Chadwick For Mailonline - Yesterday 

Traces of oil from BP's Deepwater Horizon disaster are still present more than 10 years after the devastating spill, a new study reveals.

Researchers have looked at the long-lasting effects of the explosion in April 2010 in the Gulf of Mexico on the BP-operated Macondo Prospect.

They say small amounts of 'highly weathered oil residues' from the disaster were still present in the surroundings as recently as 2020.

Oily layers coated grasses along the shorelines and some particles even sank to the seafloor, staying there for a decade.

After the Deepwater Horizon spill on April 20 2010, 210 million gallons (795 million litres) of live oil poured into the Gulf of Mexico over the course of 87 days.


Small amounts of highly weathered oil residues from the 2010 Deepwater Horizon disaster were still present in the surroundings ten years later, a study shows. 

This photo taken on April 21, 2010 by the US Coast Guard shows fire boat response crews as they battle the blazing remnants of the BP Deepwater Horizon in the Gulf of Mexico


Tendrils of crude oil cover the waters of the Gulf of Mexico following the explosive sinking of the BP operated Deepwater Horizon oil drilling rig on April 26, 2010

The glove-covered hands of Dan Howells, deputy campaign director with Greenpeace, are coated with a layer of oil after he dipped them in oil floating on the surface in the Gulf of Mexico following the BP Deepwater Horizon oil spill near Grand Isle, Louisiana, June 10, 2010

Oil slicks covered an estimated area of 57,500 square miles (149,000 square km) – an area the same size as England and Wales combined.

Staring on April 20, 2010 and lasting 84 days, it was the largest, longest lasting and deepest oil spill accident in US waters.

The new study has been led by Edward Overton, a professor at Louisiana State University's Department of Environmental Sciences in Baton Rouge, Louisiana.

'The better we understand the chemicals and their chemical reactive properties as well as their physical properties, the better we will be able to mitigate oil spills and understand and detect environmental damages from oil spills,' he said.

Related video: How to clean the world's most polluted rivers (CNBC)

Duration 13:59   View on Watch

THE DEEPWATER HORIZON DISASTER: WHAT HAPPENED?

On the night of April 20, 2010, the Deepwater Horizon, a rig owned by Transocean Ltd., burst into flames after drilling a well for BP PLC, killing 11 workers on or near the drilling floor.

The rest of the crew evacuated, but two days later the rig toppled into the Gulf and sank to the sea floor. The bodies were never recovered.

Over the next 85 days, 206 million gallons of oil - 19 times more than the Exxon Valdez spilled - spewed from the well.

In response, the nation commandeered the largest offshore fleet of vessels since D-Day, and BP spent billions of dollars to clean up the mess, saving itself from collapse.

BP was suspended from performing any new government work in America in November 2012, after it agreed to plead guilty and pay a $4.5billion fine (£2.8billion) for criminal charges over the disaster.

But it left lingering oil residues which have altered life in the ocean by reducing biodiversity in sites closest to the spill.

'Our paper describes the most abundant chemicals that make up typical crude oil and their potential fates in the environment.'

Overton and his collaborators focused on the components that were present at the highest concentrations in spilled oil and those that are the most toxic, as listed on the US Environmental Protection Agency's priority list.

By collecting and analysing samples from the water, seafloor and surrounding shorelines in numerous response studies, they followed 'chemical transformations' that occurred in the following months and years.

Once released into the environment, significant portions of the oil evaporated into the air (between 30 per cent and 40 per cent), they found.

Oil covered brown pelicans found off the Louisiana coast and affected by the BP Deepwater Horizon oil spill in the Gulf of Mexico wait in a holding pen for cleaning at the Fort Jackson Oiled Wildlife Rehabilitation Center in Buras, Louisiana, June 11, 2010

Water-soluble chemicals dissolved relatively quickly into the sea and were biodegraded by marine organisms.

However, this was not true for all of the spilled oil's components, as oily layers coated the shorelines grasses and some particles even sank to the seafloor.

Large portions of the spill also underwent sun-dependent chemical transformations or were degraded by microbes.

Workers are seen as they use a vacuum hose to capture some of the oil washing on to Fourchon Beach from the Deepwater Horizon oil spill in the Gulf of Mexico on June 28, 2010 in Port Fourchon, Louisiana

'Oil's compounds are a type of material that can be degraded by sunlight and marine bacteria (biodegradation), in contrast to other types of pollutants such as the chlorinated pesticides like DDT,' said Professor Overton.

'Oil spills release lots of chemicals quickly and most damage from oil spills occurs fairly soon after the spill.'

The team also said oil goes through transformations that are dependent on the local conditions and weather, which makes them difficult to predict for future spills.

'Environmental circumstances surrounding specific spills greatly affect how quickly the compounds can react, what they cover or coat and how much oxygen can be taken up in critical habitats,' said Professor Overton.

The study has been published today in the journal Frontiers in Marine Science. Read more

BP's green energy targets will be tough to meet

Shadia Nasralla, Susanna Twidale


LONDON (Reuters) - BP (BP.L) will need to invest tens of billions of dollars over the next decade and may have to accept lower returns than it can get from oil if it is to meet its target of becoming one of the world’s largest renewable power generators.



FILE PHOTO: The logo of BP is seen at a petrol station in Kloten, Switzerland October 3, 2017. REUTERS/Arnd Wiegmann/File Photo

The British oil and gas company wants 50 gigawatts (GW) of renewables such as wind, solar and hydropower in its portfolio by 2030, up from just 2.5 GW now and more than the total renewable capacity in the United Kingdom at the moment.

European oil firms are under pressure from activists, banks, investors and some governments to shift away from fossil fuels and are trying to find business models that offer higher margins than the mere production of renewable energy would generate.

Last week, BP followed Eni (ENI.MI) in committing to cut its oil production over the coming decade and set a bigger target for reductions than the Italian company.

Analysts say large offshore wind farms probably offer the quickest route for BP to scale up but as they can take years to develop, and have high start-up costs, it may have to turn to acquisitions - and they won’t come cheap.

“Getting value for that will be hard because these assets are very attractive and selling at very high prices,” said Peter Atherton, associate at British strategy consultants Stonehaven.

BP already has debt of $41 billion and as investors increasingly turn away from fossil fuel producers in favour of green energy firms, its shares have halved over the past two years, slashing its market value to under $80 billion.

By contrast, shares in Denmark’s Orsted (ORSTED.CO), one of the world’s biggest offshore wind developers, have surged 135% over the same period to give it a market value of $60 billion.

Orsted currently has 10 GW of installed wind power capacity - still only a fifth of BP’s target - and has committed to add another 3.8 gigawatts.

Shares in Spanish utility company Iberdrola (IBE.MC), which has 33 GW of installed renewable power and is developing several projects, have jumped 78% over the past two years, bringing its market capitalisation to $80 billion, on a par with BP.

Global renewable capacity is just over 2,500 GW, according to the International Renewable Energy Agency, but that is expected to grow rapidly as countries seek to lower emissions to meet targets set under the 2015 Paris Climate agreement.


International Energy Agency data shows that renewables, including wind, solar and hydropower, accounted for about a quarter of the electricity produced in countries in the Organisation of Economic Co-operation and Development last year.

(Graphic: Renewable power operators' shares outperform oil producers, here)

STRATEGY RISKS

In a strategy update on Tuesday, BP said it would cut its oil and gas output by 40% by 2030 and spend $5 billion a year on low carbon projects that it hopes will turn it into one of the world’s biggest green power producers.

It is also planning to sell oil and gas assets that won’t be economically viable with lower oil prices to raise $25 billion by 2025 to help fund its transition to cleaner energy.

With renewable power companies trading at high price-to-earnings ratios, analysts say BP could also build wind farms from scratch but they would come with high upfront costs.

For example, Iberdrola’s 3.1 GW East Anglia wind hub project off the British coast is expected to cost about $8 billion while SSE (SSE.L) and Total’s (TOTF.PA) 1.1 GW Seagreen 1 British offshore wind project is expected to cost some $3.7 billion.

Biraj Borkhataria, an analyst at Royal Bank of Canada, estimates that BP will have to spend about $60 billion to achieve its renewables target, assuming a 50/50 split between offshore wind and solar power production.

On the assumption that 70% of that amount could be raised through project financing, BP would need to make net capital spending of $18 billion over the next decade, he said.

Jason Gammel, an analyst at investment bank Jefferies, put the bill for BP at about $30 billion plus project financing, but said the plan still depended on renewable energy assets both being available and offering acceptable returns.


“The capital requirements assume that there are sufficient opportunities available with acceptable rates of return, which we view as key risks to the strategy,” he said.

(Graphic: European oil and gas majors' power targets, here)


Large oil firms generally target a return on oil investments of about 15%. BP said it expects returns of 8% to 10% from its low-carbon electricity investments, with the traditional oil and gas units pushing overall returns to 12% to 14% by 2030.

BP's two biggest shareholders, BlackRock (BLK.N) and Vanguard, declined to comment on its renewables strategy. Vanguard said it held most of its BP shares in index funds. Another big investor, Legal & General (LGEN.L), had no immediate comment. Other fund managers, including Allianz (ALVG.DE), did not respond to requests for comment. (Graphic: Renewable power generation by technology, here)

LEAP OF FAITH?BP Chief Executive Bernard Looney said on a conference call last week that the company would only go after renewable capacity that came with the right returns - rather than chasing capacity for the sake of it.

BP’s finance chief Murray Auchincloss told the same call that the company’s huge trading business, its ability to package renewable power with natural gas to guarantee flow rates, and its expertise with currencies and hedging services can push returns “well into the double-digit range”.

Some analysts are sceptical.

Royal Bank of Canada’s Borkhataria expects the return on renewables to be about 7%.

“It’s difficult to see these being double-digit return projects,” he said. “The energy sector has been unable to execute its strategy on its core business, so I’m not that confident in taking another leap of faith on a new business.”

Lead oil and gas analyst at Fitch ratings agency, Dmitry Marinchenko, said while renewables might be a less profitable business now, BP was betting that returns from oil and gas would be weaker in the future.

“The energy transition road will be bumpy for oil majors; they have little experience in renewables and new investments will make them subject to the execution risk. Not all investments will probably prove to be successful,” he said.

“However, the ‘business as usual’ approach could be overly risky in the long term. Reinventing the business now that oil prices are still relatively high should be easier than in 10 years’ time.”

Reporting by Shadia Nasralla and Susanna Twidale; Editing by David Clarke

10 YEARS AGO THEY TRIED TO REBRAND THEMSELVES AS 'BEYOND PETROLEUM' AND THEN CAME THE DEEPWATER HORIZON DISASTER

Beyond Petroleum? | WWF

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Beyond Petroleum? Posted on 18 February 2020. It is a measure of how far the climate debate has come that BP, one of the world's largest producers of fossil ..

BP's "Beyond Petroleum" Campaign Losing its Sheen | PR ...

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May 3, 2010 - Back in July, 2000, British Petroleum launched a high-profile, $200 million public relations ad campaign designed by Ogilvy & Mather to ...

Deepwater Horizon – BP Gulf of Mexico Oil Spill | Enforcement ...

https://www.epa.gov › enforcement › deepwater-horizon-bp-gulf-mexico-...

On April 20, 2010, the oil drilling rig Deepwater Horizon, operating in the Macondo Prospect in the Gulf of Mexico, exploded and sank resulting in the death of 11 workers on the Deepwater Horizon and the largest spill of oil in the history of marine oil drilling operations.

What caused the Deepwater Horizon disaster? - Resilience

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May 21, 2010 - The blowout and oil spill on the Deepwater Horizon in the Gulf of Mexico was caused by a flawed well plan that did not include enough cement ..

Deepwater Horizon disaster had much worse impact than ...

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Feb 13, 2020 - The environmental impact of the Deepwater Horizon oil spill disaster in the Gulf of Mexico a decade ago was much worse than previously ...

'Beyond Petroleum' No More? BP Goes Back to Basics

https://www.cnbc.com › ...

Apr 22, 2013 - After a very public campaign to promote renewable energy, BP is inaugurating Earth Day as a markedly less "green" company — highlighting ...

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Feb 1, 2019 - BP's shock decision to publish a Paris Agreement consistent strategy is a huge win for investors, but who decides how to define 'consistent'?

Opinion: Is BP's Beyond Petroleum campaign back? Don't ...

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Jun 16, 2020 - As if to prove the point, BP, the former British Petroleum that is Europe's second-biggest oil company, on Monday unveiled oil and natural gas ...

Is BP Finally Moving Beyond Petroleum? | OilPrice.com

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Jun 22, 2020 - Shortly before “Beyond Petroleum” was launched, BP made some instructive acquisitions. For $26.5bn, it acquired the oil-drillers ARCO. This was ...

After Abandoned 'Beyond Petroleum' Re-brand, BP's New ...

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AUGUST 4, 2020- “We need to go beyond petroleum.” Just shy of 20 years ago, the oil giant BP infamously re-branded itself from “British Petroleum” to “beyond .

 

12 Years Later: The Deepwater Horizon Spill

The fire aboard the Deepwater Horizon, April 2010 (USCG)

PUBLISHED APR 27, 2022 5:31 PM BY WILLIAM THIESEN

 

"Even Exxon Valdez pales in comparison to the volume, scale, number of Coast Guard resources, how much time has been devoted to [Deepwater Horizon]—all far exceed any previous event." - Capt. Duke Walker, Federal On-Scene Coordinator, U.S. Coast Guard, 2012

On the evening of April 20, 2010, the Deepwater Horizon oil rig blew up at the Macondo well site, 45 miles southeast of Venice, Louisiana. The explosion resulted in the deaths of 11 workers and, within two days, the loss of the rig. The resulting spill of over 200 million gallons of crude oil became the largest discharge of oil in U.S. waters.

A century earlier, petroleum products had fueled tremendous growth in industrial, government and civilian uses. Oil products became common ship fuel and cargo and, offshore oilrigs grew in numbers as land-based reserves dried up.

The Coast Guard’s role in oil and chemical spill response officially began in 1924, when Congress passed the Oil Pollution Act. This act included the first federal statutes regulating the discharge of fossil fuels from seagoing vessels. In 1948, Congress passed the Federal Water Pollution Control Act to protect public water supplies for public, agricultural, recreational and industrial uses. Coast Guard veterans will remark how laws mandating the service’s search and rescue mission were written in blood, but the service’s pollution response mission laws were written in oil.

After World War II, chemical spills and hazardous waste events began to occur frequently. Major spills in the 1960s brought attention to oil and chemical pollution, including the tanker Torrey Canyon oil spill in 1967 and the 1969 fire on Cleveland’s polluted Cuyahoga River. The 1969 Santa Barbara Oil Spill focused attention on the dangers of spills from offshore oil rigs. With these environmental disasters came greater awareness of chemical pollution spurring enactment of the U.S. National Oil and Hazardous Substances Pollution Contingency Plan (a.k.a. “NCP”) in 1968 and, in 1970, passage of the Water Quality Act and establishment of the nation’s annual Earth Day observance.

By the 1970s, tanker oil spills averaged nearly 80 per year worldwide. With these frequent spills came regulation of oil tankers and better technology for responding to spills. Congress tasked the Coast Guard with monitoring unauthorized substance discharge, enforcing ballast water regulations and ensuring that commercial vessels met U.S. environmental standards. In 1972, Congress made sweeping amendments to the Water Pollution Control Act, which came to be known as the Clean Water Act and resulted in establishment of the Coast Guard’s National Strike Force (NSF). In the 1970s and 1980s, the NSF’s oil and chemical spill responsibility expanded under several more environmental protection laws passed by Congress.

In 1989, the tanker Exxon Valdez ran onto a rock ledge near Valdez, Alaska, causing the worst oil spill in U.S. waters up to that time. The disaster led to passage of the Oil Pollution Act of 1990 (OPA 90). OPA 90 regulations created the Oil Spill Lability Trust fund and codified the “polluter pays” principle. OPA 90 also required alcohol and drug abuse monitoring of licensed mariners, and established legal penalties and a claims system for oil spill remediation. Enforcement of OPA 90 and protection of U.S. territorial waters became a vital part of the Service’s mission and led to a more robust Coast Guard response capability.

Picture of the tanker Exxon Valdez in 1989 after she ran aground in Prince William Sound, Alaska, and spilled 15 million gallons of crude oil. (U.S. Coast Guard)

After Exxon Valdez, Coast Guard assets and personnel continued to respond to all kinds of oil and hazardous material releases, even some beyond U.S. waters. These events included the sabotaged oilrigs of the 1990 Persian Gulf War and consequent oil spills—considered one of the largest discharges of oil in history. Other spills included those caused by hurricanes Floyd, Katrina and Rita; barge and tanker oil spills of the 1990s and early 2000s; and aviation accidents, such as the 1999 Egypt Air and 2000 Alaska Airlines crashes.

Coast Guard units, including the NSF, played a leading role in responding to the Haiti Earthquake in 2010. That same year, the Deepwater Horizon rig explosion occurred. The resulting spill is considered the world’s largest maritime oil spill and the largest environmental disaster in U.S. history. The Deepwater gusher spewed oil into the Gulf of Mexico at a rate of 60,000 barrels per day for nearly 90 days. The oil slick covered thousands of square miles of water and nearly 4,500 miles of Gulf shoreline.

Relief well drilling operations at the Deepwater Horizon response site (USCG)

Daniel Beltra / Greenpeace

From April 2010 through April 2014, the Coast Guard led the effort to clean and evaluate shoreline segments along the Gulf of Mexico. In 2012 and in 2013, the shoreline-cleaning program collected around seven million pounds of oily material. By the summer of 2013, shoreline remediation was deemed complete on the Gulf shores of Texas, Mississippi, Alabama and Florida. In 2014, the program collected around 30,000 pounds of oily material, about one percent of the previous year’s total. By 2014, the bulk of oily material found consisted primarily of small tar balls dispersed along the shorelines. By then, it became difficult to distinguish between oil from Deepwater Horizon and oil from other sources found along the shoreline. By late February 2015, the Coast Guard shifted operational oversight of response effort to local commands along the Gulf Coast. 

The Coast Guard’s response to the Deepwater Horizon spill became the largest for an environmental disaster in the Service’s history. At the height of the effort, the Coast Guard-led command oversaw an armada of over 6,000 vessels, including skimmers, vessels of opportunity, research vessels, Coast Guard cutters, and specialized vessels. This command also established an Aviation Coordination Center that oversaw more than 120 aircraft vital to the response effort. To ensure the flow of commerce in the impacted area, the Coast Guard established a Marine Transportation System Recovery Unit. The combined efforts of these assets involved nearly 50,000 Coast Guard and civilian personnel.

Today, as part of its homeland security obligations, the Coast Guard responds to human and environmental impacts of oil discharges, hazardous material releases, and other disasters. The Coast Guard remains ready, relevant and responsive to adapt and expand its environmental protection mission to ever-changing natural and manmade threats to the nation and its marine environment.

William Thiesen is the Coast Guard Atlantic Area historian. This article was first released in 2020, and it is reproduced here courtesy of Coast Guard Compass. The original is no longer available online. 

The opinions expressed herein are the author's and not necessarily those of The Maritime Executive.

POLITICAL ECOLOGY
Deepwater Horizon spill has long-term effects on dolphins' immune systems


Scientists have been regularly capturing, sampling and releasing bottlenose dolphins exposed to the Deepwater Oil spill in 2010, and report that the immunological effects on the mammals can still be seen -- even in younger dolphins. Photo by Todd Speakman

Feb. 18 (UPI) -- Ten years after the Deepwater Horizon rig exploded in the Gulf of Mexico, triggering the largest marine oil spill in history, dolphins are still experiencing the immunological effects of exposure, according to a study published Thursday in the journal Environmental Toxicology and Chemistry.

The new research is only the latest study to show the effects of the Deepwater Horizon spill were larger and longer-lasting than previously estimated -- capable of disrupting entire food webs and even affecting animals on land.

Over the last decade, researchers have been regularly capturing, sampling and releasing bottlenose dolphins in Barataria Bay, Louisiana, where oil exposure was extensive.

Researchers compared levels of cytokines -- immunological proteins -- in dolphins from Barataria Bay with the immune system profiles of dolphins in Sarasota Bay, which remained oil-free.

RELATED Survey shows pollution in Gulf 10 years after Deepwater Horizon spill

In the new study, researchers even found evidence that dolphins born after the oil spill host cytokine communities similar to their parents.

Scientists were able to replicate the immunological effects of oil exposure in the lab using mice models.

They were also able to show oil exposure influenced the immune systems of the next generation of mice, even though the newborn mice were unexposed.

RELATED On This Day: Deepwater Horizon oil rig explodes

"The parallel between findings in dolphins exposed following the Deepwater Horizon spill and laboratory mice experimentally exposed to oil was impressive and really helped build the weight of evidence between oil exposure and specific effects on the immune system," corresponding author Sylvain De Guise said in a news release.

"However, the long-term effects and potential for multigenerational effects raise significant concerns for the recovery of dolphin populations following the spill," said De Guise, a postdoctoral researcher at the University of Connecticut.

RELATED Deepwater Horizon oil spill was bigger than previously thought, study finds


RELATED More than 260 dead dolphins found on Gulf Coast since February

DEEPWATER HORIZON LEGACY

Red Snapper in the Gulf show signs of stress

UNIVERSITY OF SOUTH FLORIDA (USF INNOVATION)

Research News

 

IMAGE: ONE OF THE RED SNAPPER SAMPLED AS PART OF THIS GULF-WIDE STUDY IN THE WAKE OF THE DEEPWATER HORIZON OIL SPILL. view more 

CREDIT: UNIVERSITY OF SOUTH FLORIDA

Nearly 100 percent of the red snapper sampled in the Gulf of Mexico over a six-year period by University of South Florida (USF) marine scientists showed evidence of liver damage, according to a study reported in Aquatic Toxicology.

The study is the first to correlate the concentration of crude oil found in the workhorses of the digestive system -- the liver, gall bladder, and bile - with microscopic indicators of disease, such as inflammation, degenerative lesions, and the presence of parasites. The team sampled nearly 570 fish from 72 Gulf locations between 2011 to 2017 in the wake of the historic 2010 Deepwater Horizon oil spill.

"The results add to the list of other species we've analyzed indicating early warning signs of a compromised ecosystem," said Erin Pulster, PhD, first author of the study and researcher at the USF College of Marine Science.

Pulster and the team of researchers studying oil pollution in Gulf of Mexico fishes have previously reported high levels of oil exposure in yellowfin tuna, golden tilefish, and red drum as well.

The Gulf of Mexico not only experiences hundreds of annual oil spills with long-lasting effects such as the historic Deepwater Horizon spill in 2010 but is routinely subject to intense shipping traffic and collects pollutants from faraway places that flow in from coastlines and rivers like the Mighty Mississippi and the Rio Grande.

In this study Pulster and the team looked specifically at the most toxic component of crude oil called polycyclic aromatic compounds, or PAHs. PAH sources include old oil and gas rigs, fuel from boats and airplanes, and natural oil seeps, which are fractures on the seafloor that can add millions of barrels of oil to the Gulf every year.

CAPTION

Mean concentrations of polycyclic aromatic hydrocarbons (PAHs, which are labeled here as total fluorescent aromatic compounds)in the bile (biliary, top map) and the liver (hepatic, bottom map)in the red snapper study that took place 2011-2017.

CREDIT

University of South Florid

The presence of PAHs in the bile, which is produced by the liver to aid in digestion, indicates relatively recent oil exposure (days to weeks). The team found that the PAH concentration in the bile declined and remained relatively stable after 2011 but they noted a sharp increase in 2017.

Overall, the bile PAH "hot spots" were on the West Florida Shelf (WFS) and in the vicinity of the Deepwater Horizon spill, off the mouth of the Mississippi River. This is the site of the 2004 Taylor oil platform collapse off Louisiana, the longest oil spill in history, which continues to leak oil today. The hotspot west of Tampa on the WFS could be due to shipping traffic or submarine groundwater discharge, Pulster said.

PAH found in the liver indicates the fish has been chronically exposed to oil (months to years). The team found the liver PAH "hot spots" in the northwest Gulf of Mexico, where a considerable number inactive oil and gas platforms exist.

While the PAH concentrations in the liver remained relatively stable throughout the study, indicating that the red snapper are physically managing the oil exposure, there is a tipping point, Pulster said. Red snapper can live upwards of 40 years but fish manage oil toxins, similar to the way humans manage exposure to greasy burgers and alcohol.

Repeated exposure to oil in fish can lead to cancer and eventually to death, but it can also result in sublethal impacts. Virtually all (99 percent) of the red snapper sampled had an average of five physical signs of liver damage. The observed changes can result from natural causes but are also well documented secondary responses to stress which, could potentially signal disease progression.

"We just don't know when we will tip the scale," said Pulster. There was literally one red snapper in the bunch with PAHs but no physical signs of damage when viewed under the microscope, said Pulster.

It's a good thing that humans only eat the muscle of the fish, not the liver. Red snapper remain safe to eat but Pulster stressed the need for continued monitoring. Only then can scientists keep their finger on the pulse of fish health and know what the impacts of additional oil spills may be - especially in species like snapper that are so critical to the Gulf economy, she said.

"This is a unique study. Most investigations of oil spill effects only last a year or two, and this study gives us both a wide scale of reference across the Gulf and also long-term monitoring, which we lacked prior to Deepwater Horizon," said Steve Murawski, PhD, senior author on the study. Murawski, a professor and the St. Petersburg Downtown Partnership Peter R. Betzer Endowed Chair at the USF College of Marine Science, led the 10-year research effort in response to the Deepwater Horizon oil spill (C-IMAGE (usf.edu).

"There is a story we can tease out of the data," Murawski said. "The observed decline in oil exposure in red snapper in the few years following the Deepwater Horizon accident suggests the high levels measured in earlier years were a direct impact from the spill. Its legacy continues, and we'd be wise to continue the critical research ironically made possible by long-term monitoring post-disaster."

###

The study was supported by The Gulf of Mexico Research Initiative, and The Center for the Integrated Modeling and Analysis of the Gulf Ecosystem (C-IMAGE I, II, and II).

CAPTION

This table outlines the prevalence (%) of physical microscopic signs of liver damage, such as inflammation, observedin the red snappercollected from different regions of the Gulf of Mexico (North Centralor NC, Northwest or NW, Southwest or SW, and Gulf-wide).

CREDIT

University of South Florid