Ecological Impacts of the Deepwater Horizon Oil Spill: Implications for Immunotoxicity

Abstract

The Deepwater Horizon (DWH) oil spill was the largest environmental disaster and response effort in U.S. history, with nearly 800 million liters of crude oil spilled. Vast areas of the Gulf of Mexico were contaminated with oil, including deep-ocean communities and over 1,600 kilometers of shoreline. Multiple species of pelagic, tidal, and estuarine organisms; sea turtles; marine mammals; and birds were affected, and over 20 million hectares of the Gulf of Mexico were closed to fishing. Several large-scale field efforts were performed, including assessments of shoreline and wildlife oiling and of coastal waters and sediments. The assessment of injuries, damages, and restoration options for the DWH spill is ongoing. Although petroleum and the polycyclic aromatic hydrocarbon component of oils are known to affect the immune systems of aquatic organisms and wildlife, immunotoxicity is not typically assessed during oil spills and has not been a focus of the DHW assessment. The effects of oil spill contaminants on immune responses are variable and often exposure dependent, but immunotoxic effects seem likely from the DHW spill based on the reported effects of a variety of oils on both aquatic and wildlife species.

Oil Characterization and Distribution in Florida Estuary Sediments Following the Deepwater Horizon Spill

“…Locations are shown in Figure 1 and described in Table 1 Table 1 for site identifications and Figure 1 for sample location. Sediment samples collected July (FP) and August (NAS) 2010; 2 Rosenbauer et al [3,16]; 3 One or more analytes below detection limits; 4 Mulabagal et al [17]; 5 Hostettler et al [18]; 6 Alkane to isoprenoid ratio [14]; 7 Douglas et al [19] …”

“…The Deepwater Horizon (DWH) oil rig exploded on 20 April 2010, initiating the discharge of 800 million liters of oil into the northern Gulf of Mexico over an approximately three month period [1][2][3]. The spill was the largest environmental disaster in United States history, and the largest accidental oil spill in human history [4].…”

“…Vast areas of the Gulf of Mexico were impacted by oil, including deep ocean, pelagic, and estuarine ecosystems. Over 20 million hectares of the Gulf of Mexico were closed to fishing and 1600 km of shoreline were visibly oiled [2,5]. Shoreline oiling was temporally and spatially heterogeneous, with the heaviest oiling occurring in coastal areas of eastern Louisiana, Mississippi, Alabama, and on the barrier islands of Northwest Florida [6].…”

Fighting oil spills at sea and toxicology of complex mixtures

“…In fighting the Deepwater Horizon oil spill, about 7 million liters of chemical dispersants were used, and for the first time, oil dispersants were used in deep-sea environments (Barron 2012). The main dispersant was Corexit 9500A that, according to press releases, contained light petroleum distillates, propylene glycol, and dioctyl sodium sulfosuccinate as detergent (Schor 2010 …”

“…Multiple pelagic, tidal, and estuarine organisms were affected at the Gulf of Mexico. The immediate toxic ological/ecotoxicological focus was on petroleum ingredients, including polycyclic aromatic hydrocarbons (Barron 2012).…”