SETAC Globe - Environmental Quality Through Science
  9 June 2011
Volume 12 Issue 6

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Gulf Oil Spill Focused Topic Meeting a Major Success

Marc Greenberg, U.S. EPA Emergency Response Team; Bill Goodfellow, EA Engineering Science & Technology; Bruce Vigon, SNA Scientific Affairs Manager; Greg Schiefer, SNA Executive Director

The SETAC Gulf Oil Spill Focused Topic Meeting agenda—fate and effects, food contamination, modeling, etc.—covered all the major aspects of the spill in a participatory and integrated manner. That was the feedback from one enthusiastic attendee, and reflects the prevailing view of the 250+ participants. More than 90% of the meeting-specific survey responses rated the scientific value of the meeting “good” or “excellent” and more than 90% recommended that SETAC North America conduct another oil spill focused topic meeting next year.

This meeting attracted a diverse group of oil spill assessors and responders with expertise in toxicology, chemistry, modeling and tracking of oil, technology development, emergency response, environmental management and risk communication. With such a large turnout for a meeting that was organized in less than five months, it was obvious that many feel the need to assess where we are today, what we think we know or don’t know, and what and how we should organize our scientific resources going into the future.

The meeting provided a multi-stakeholder forum for exchange of current and developing knowledge on key aspects of the spill. This non-traditional approach to a SETAC meeting was well received by the participants, based on survey responses. The format was designed to promote interaction among participants. A combination of platform presentations, posters, and panel discussions facilitated exchange and joint learning along two main topic tracks: Biological Effects of Oil Spills, and Current Technology and Capabilities. Special panel discussions were held on Communication Challenges and Solutions, and Oil Spill Response and the Incident Command System.

A number of critical issues were raised during the meeting, including (but not limited to)

  • The “but-for-the-dispersant” question. It was generally understood—and by many it appeared to be taken as a fact—that dispersants and dispersed oil are hazardous to aquatic species. It was likewise assumed—and perhaps taken as an axiom—that oil dispersal is positive for the environment in that it reduces oil impacts to shorelines, beaches, and marshes. The tension between these points has yet to be resolved. There seems to be no quantitative measurement of the environmental effectiveness of dispersant use or a post hoc tradeoffs analysis, although the decision to use dispersant was based on a net environmental benefit analysis. The discussions indicated that the participants felt that a rigorous analysis of the risks and benefits of dispersant use in spill response is warranted, given the myriad of receptors and habitats, exposure regimes, and modes of effect. Developing better information to support decisions on the use of oil dispersants will require a holistic and integrated approach.
  • Successful oil spill response relies on access to a complete “toolbox” of response techniques. It may include subsea containment, remote sensing, mechanical recovery, surface and subsea use of dispersants, in situ burning, and natural attenuation. These response techniques are each most efficient under different conditions (e.g., oil properties, release scenarios, environmental conditions) and should all be evaluated for their applicability in dynamic spill response situations. Several of the discussions centered on how to improve or enhance the toolbox, and how to better choose the tools for the task at hand.
  • Regarding seafood safety, the results presented indicated that seafood samples were 100-1,000 times below levels of concern for PAHs and dispersant markers. A segment of one panel discussed the adequacy of the equivalency approach used, in that the number and relative toxicity of the individual PAH compounds taken into account results in a lower margin of safety than was claimed/presented in public forums (still below thresholds but less than the reported 100 to 1,000 times).
  • It was asserted during the meeting that even though health agencies have determined based on extensive data that Gulf seafood is safe to eat, many people don’t accept that. The phrase “you can’t truth your way out of it” was used to convey the sense that technically factual information is not necessarily persuasive. This led to discussions on how to improve risk communication.
  • Oil transport occurred within two main regimes based on particle size: a subsea plume of dispersed particles (<100 microns) and associated dissolved compounds; and a surface plume (>1 mm). The fate of the oil within these regimes (e.g., the degree of weathering, bioavailability for degradation, bioavailability of toxic constituents, and oiling of shorelines and the sea bottom) is significantly different. The proportions of the spilled Macondo oil that entered these regimes are presently unknown. Panel discussion identified a combination of needs from better (higher resolution) data on particle size distributions to a variety of fate and effects modeling issues. Some of the modeling conversations focused on environmental compartments that are not well addressed. Others focused on overall improvements to the multi-media integrated models themselves. There was a broad consensus that until the fate of the oil is better understood, no one is in a strong position to forecast ecosystem-level effects of the spill.

These are just a few of the topics and issues that were identified as needing more focused work to improve spill response and tracking, control techniques, management and effects assessment. Look for more SETAC reports, publications, and activities related to the Gulf Oil Spill in coming months, and go to the meeting blog. If you want to make a contribution to the blog, here’s a link to an input form to capture your thoughts:

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