To clean oil from beaches, sand washing and surf washing were performed. To clean oil from marshes, physical removal of the oil by manual labor, floating machinery, and manual cropping of oiled vegetation were employed.
Almost all countermeasures and response options have limitations and environmental effects that ultimately will impact ecosystem services. If the goal of response efforts is to protect the environment that sustains the ecosystem services, then we must realize that prioritization among the services involves complex decisions and the selection and application of response technologies involves tradeoffs. Most decisions regarding the application of spill response technologies after the DWH oil spill were based on NEBA,11 and they were made in consideration of the best available information at the time.
The immediate goal of the response technologies applied during the DWH oil spill was to prevent oil from reaching sensitive coastal habitats. Although none of the response tools was completely effective, the use of in situ burning, booms, skimmers, and particularly dispersants significantly mitigated the impacts of the spill along the coast. Continued remediation efforts will eventually result in diminishing returns, at which time natural attenuation of the remaining oil may be the best option. To this end, more science needs to be incorporated into the remediation process (both on- and offshore), not only to determine the most effective methods to apply under various conditions, but also to feed into the NEBA process of ascertaining the operational endpoint. Regarding the DWH oil spill, two factors raised important research questions: (1) the depth of the spill and (2) the large-scale application of emerging new technologies, such as subsurface injection of dispersants and oceanic in situ burning.
At the time of this writing, the consequences of the technologies applied to contain the oil and to prevent its reach into sensitive coastal and wetland habitats, as well as the response of the GoM ecosystem to the spill, have not been, and may never be, fully documented. Work to understand the fate and effects of the spilled oil is ongoing. Much work to determine the long-term effects remains. Understanding of the potential impacts of response technologies to ecosystem services and of the impacts of oil on multiple layers of ecosystems and their services is limited by the availability of baseline information and of important data collected during the NRDA process. Until this massive and unprecedented collection of data is complete and the results made available, any assessment of the impacts of the response technologies will not be fully informed. These issues will be discussed further in Chapter 6.
Finding 4-11. Any conclusive assessment of the impacts of response technologies on the GoM marine ecosystem and ecosystem services would be premature at this time, given the amount of key data and analyses that is being held confidentially in the ongoing NRDA process. Nonetheless, the committee believes that the technologies applied offshore mitigated the impacts of the oil spill on sensitive coastal habitats. A further factor for consideration is that only 3 years have passed since the spill started, and many substantial impacts may not become apparent for several more years.