What Next: Assessing Deepwater Horizon damages and what we have yet to learn about the oil spill's impacts

By Elizabeth Grossman

On August 17th the National Institute of Environmental Health Sciences (NIEHS) held the first public discussion of plans for its Gulf Worker Study - also called the Gulf Long Term Follow-up Study - designed to assess short and long-term health effects associated with BP/Deepwater Horizon oil disaster clean-up work. "Since the spill," said NIEHS director Linda Birnbaum opening the meeting, "NIEHS has assisted with safety training for more than 100,000 workers with courses taught in English, Spanish and Vietnamese. But now it's time to turn our attention to the potential health consequences of oil and dispersants."

The study will focus on health effects that include respiratory, cardiovascular, immune system, neurological, dermatological, and reproductive system impacts as well as cancers that may result from exposure to oil products and dispersants. It will also assess mental health and stress impacts resulting from the oil spill. As part of this effort the National Toxicology Program will conduct toxicology tests of oil and dispersant mixtures and what it describes as "blood analysis for a study on skin exposures to oil and dispersants."

Like the Deepwater Horizon event itself, this study - to which the National Institutes of Health (NIH) has committed at least $10 million - is unprecedented in scope. Expected to get underway in October, the study will begin by contacting some 70,000 Gulf Coast community members and others involved in oil spill response work. Only eight of the 38 "supertanker" oil spills that have occurred in the last 50 years have been studied for health effects, said Dale Sandler, chief of NIEHS epidemiology branch who is the study's principal investigator. The Deepwater Horizon disaster is the largest of any oil spill by far and stands to be the most studied.

NIEHS wasn't the only organization announcing or releasing an assessment of the Deepwater Horizon disaster last week. A story in the August 14 issue of The Lancet - "Anger and anxiety on the Gulf Coast" - reports on the mental health effects of the spill. "We've had contact with 8500 residents and we're getting a sense of what they're experiencing, like intense anger and anxiety, they don't know what the future's going to be or how they're going to get back to their way of life," Jimmy Guidry, medical director of Louisiana Department of Health and Hospitals and the state's health officer, told the magazine.

The Lancet notes that assessing the mental and physical health impacts of this disaster is challenging for a number of reasons. Among them is the region's chronic underfunding and lack of availability of medical clinics. Mental health problems and chronic physical ailments are already under-diagnosed in the Gulf states, and some of the prevalent but under-diagnosed conditions have symptoms that coincide with those resulting from oil and chemical exposures.

The Latest Exposure Data
Meanwhile BP and OSHA have posted their latest exposure sampling data, BP's from August 15th and OSHA's from Coast Guard Lab analyses released August 12th. In its summary, BP writes:

As of 15th August 2010, more than 14,000 personal samples have been collected on workers involved in the response. Personal monitoring results... indicate that in the vast majority of cases there are no significant exposures to airborne concentrations of chemicals of interest. This is consistent with analyses at the leak source which indicate that, by the time crude oil reaches the water's surface, constituents of most concern (e.g., benzene, toluene, ethylbenzene, and xylenes) are not present in concentrations known to be harmful. This is also consistent with results obtained by governmental agencies such as OSHA and NIOSH that have conducted their own industrial hygiene monitoring of response workers.

The latest OSHA data similarly shows most samples with no detectable level of any of the hydrocarbon compounds tested for. At the same time, in its continued health surveillance reporting, the Louisiana Department of Health and Hospitals has now logged in 361 health complaints believed to be related to the oil spill, 277 of which came from workers.

One ongoing question to ask will be whether cumulative effects of various volatile hydrocarbon compounds produce adverse health effects, given that the raw data (see the BP August 15 "detailed report") shows the presence of such compounds, among them benzene, hexane, toluene, and xylene in most samples. Another is how extreme heat and sun exposure - and for some workers, exposure to unusually high levels of particulate matter - may influence these chemicals' impacts.

Underwater Oil
While environmental, medical, and occupational health specialists are mapping out their assessment of the oil's impacts, marine biologists continue their work to understand where the estimated five million barrels of oil released from the well have gone.

On August 19th, a team of scientists from the Woods Hole Oceanographic Institute released results (published in Science) of their late June expedition to the Gulf to map and characterize the underwater oil plumes. The researchers observed an underwater plume approximately 22 miles long that persisted for months without substantial microbial degradation. Although they still have to analyze much of the data they collected, they report that the volume of aromatic petroleum compounds in the plume were more than double those that would be expected from all natural sources in that part of the Gulf.

Presenting their findings at an August 19th press conference, the researchers stressed that what they've learned to date is but a "snapshot" and that at this point not much can yet be said about the plume's bioactivity or toxicity. "We know there is a plume. We know there are some hydrocarbons there," explained Christopher Reddy of WHOI's department of marine chemistry and geochemistry. "Why does the plume matter? It's an uninvited guest," said Reddy. It will be months before the extent of the underwater oil's impacts - on marine life and overall Gulf ecology - are better understood, but this research confirms its presence and persistence.

Yet complicating how this and other Deepwater Horizon-related research proceeds is the Natural Resources Damage Assessment (NRDA) process, which will ultimately determine the extent of damages caused by the oil and, hence, what must be restored.

Where WHOI's research is concerned, the process is one of "complete transparency," says Chris Reddy. "There is nothing being withheld as part of the NRDA process with respect to WHOI," Reddy told me via email.

Tom Brosnan of NOAA's Office of Response and Recovery reminds those interested in human health impacts that the NRDA only looks at natural resources and wildlife habitat and does not take into account human health effects. "No human health, no seafood safety," Brosnan told me. "And it's not just to answer interesting scientific questions, but to address liability and restore what's been damaged."

Also to watch will be how the damage to the Gulf's marine life will be distinguished from damage to the Gulf's human communities. Because so many of the region's residents depend on a productive marine environment for their livelihoods, the health of the Gulf ecosystems and the health of its human communities are inextricably linked. As U.S. Surgeon General Regina Benjamin who ran a medical clinic in Bayou La Batre, Alabama said, as quoted by The Lancet, "With this, you continue to ask every day: 'When will our oyster beds be back? When will our jobs come back?'"

Elizabeth Grossman is the author of Chasing Molecules: Poisonous Products, Human Health, and the Promise of Green Chemistry, High Tech Trash: Digital Devices, Hidden Toxics, and Human Health, and other books. Her work has appeared in a variety of publications including Scientific American, Salon, The Washington Post, The Nation, Mother Jones, Grist, and the Huffington Post. Chasing Molecules was chosen by Booklist as one of the Top 10 Science & Technology Books of 2009 and won a 2010 Gold Nautilus Award for investigative journalism.


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One minor clarification: OSHA and the USCG are taking personal samples independently of each other, but those samples are all being analyzed by the OSHA laboratory and all are being posted on OSHA's website.

I'd like to know more about the dispersants. We know millions of gallons of two "Corexit" formulas released along with the oil (similarly numbered but utterly different from one another), and a large amount of something called "Dispersit". Do we know how much of each was used, and when? Reports suggest that they are supposed to degrade on exposure to air, but not when deep under water. Are deep oil/water samples analyzed for content of these mixtures? Are they toxic to different bacteria in different degrees? Are there microbes in the Gulf to degrade every component of them, or do some persist?

I wonder why oxygen wasn't injected along with the dispersants, to provide the extra needed by the microbes expected to degrade the oil.

By Nathan Myers (not verified) on 25 Aug 2010 #permalink