A Decade of GoMRI Dispersant Science: Lessons Learned and Recommendations for the Future

Abstract

Dispersants are among a number of options available to oil spill responders. The goals of this technique are to remove oil from surface waters in order to reduce exposure of surface-dwelling organisms, to keep oil slicks from impacting sensitive shorelines, and to protect responders from volatile organic compounds. During the Deepwater Horizon response, unprecedented volumes of dispersants (Corexit 9500 and 9527) were both sprayed on surface slicks from airplanes and applied directly at the wellhead (~1,500 m water depth). A decade of research followed, leading to a deeper understanding of dispersant effectiveness, fate, and effects. These studies resulted in new knowledge regarding dispersant formulations, efficacy, and effects on organisms and processes at a broad range of exposure levels, and about potential environmental and human impacts. Future studies should focus on the application of high volumes of dispersants subsea and the long-term fate and effects of dispersants and dispersed oil. In considering effects, the research and applications of the knowledge gained should go beyond concerns for acute toxicity and consider sublethal impacts at all levels of biological organization. Contingency planning for the use of dispersants during oil spill response should consider more deeply the temporal duration, effectiveness (especially of subsurface applications), spatial reach, and volume applied.

Biogeochemical Processes Affecting the Fate of Discharged Deepwater Horizon Gas and Oil: New Insights and Remaining Gaps in Our Understanding

“…• Understanding and documenting the influence of mitigation measures/ techniques, such as aerial dispersant applications and in situ burning, on the movement of weathered oil into MOS and into the water column and to deep sediments by MOSSFA events (Quigg et al, 2021, in this issue).…”

Human Health and Socioeconomic Effects of the Deepwater Horizon Oil Spill in the Gulf of Mexico

“…Chemicals of concern in crude oil, those potentially toxic to humans, are the volatile aromatic hydrocarbons, BTEX-H, and the polycyclic aromatic hydrocarbons (PAHs) (ATSDR, 2005). Mitigation of oil spills can also include the use of dispersants, for which potential toxicities to humans are under debate (Ferguson et al, 2020a;NASEM, 2020;Quigg et al, 2021, in this issue); their use would need to be considered in risk assessments for future oil spills. Of the chemicals listed above, the PAHs and their degradation products have the most significant impacts at beaches because they weather slowly and are generally the most toxic (ATSDR, 2005).…”

Technological Developments Since the Deepwater Horizon Oil Spill

“…In this section, we feature developments related to defining the interactions of waves, oil, and dispersed oil; processes that drive the formation of marine aerosols and their transport; and human exposure risks from aerosolized volatile organic compounds and particulate matter. Related topics are also discussed in Boufadel et al (2021, Quigg et al (2021), Rullkötter and Farrington (2021), and Sandifer et al…”

“…We also describe novel approaches for investigating oil-induced physiological and ecological impacts on commercially and environmentally important fish and marine mammal species that help to provide a more comprehensive understanding of acute and sublethal effects on long-term population dynamics. Topics related to oil spill impacts on marine life are also discussed in Farrington et al (2021), Halanych et al (2021), Quigg et al (2021), Murawski et al (2021), andSandifer et al (2021), all in this issue. White et al (2012) combined the use of technologies that can operate in the deepsea environment with three-dimensional seismic data to find, image, identify, and collect samples of a damaged octocoral community 13 km southwest of the DWH site.…”