Lingering Oil: Continued

Based on the 2014 survey of the communities in Prince William Sound of Cordova, Tatitlek, and Chenega Bay, Fall and Zimpleman (2016) reported that most respondents expressed confidence in the safety of using subsistence foods, and this level of confidence has increased since 2003. Few respondents pointed to contamination from the Spill as a source of concern about food safety. However, they also reported that a small but notable portions of respondents expressed concerns about food safety, especially related to Pacific herring and clams. Some key respondents wondered if lingering EVOS--contamination concerns were not voiced due to a strong preference for eating traditional foods (such as clams). Exxon Valdez oil contamination was commonly cited as a cause of food safety issues among those who did express a concern.

Fall and Zimpleman (2016) concluded that subsistence harvests remain an important source of food in the study communities, include a wide range of species, are frequently shared, and provide a context for expressing and sharing the skills and values intimately linked to centuries-old traditions and future cultural survival. However, the study also documented relatively low harvests compared to other post-spill years. Subsistence uses were also less diverse in 2014 than in any study year except for the first two years after spill. Many respondents stated that youth are not learning subsistence skills, elders are not engaged in transmitting essential knowledge and values, many natural resource populations have declined or are difficult to access, and the traditional way of life has not recovered from the effects of the Spill.

Fall and Zimpleman (2016) suggested potential actions to include local communities in restoration efforts as well as strengthen communities for their future. These recommendations included support for cultural camps and other ways to engage elders with youth, programs to assist community residents to participate in fishing, hunting, and gathering activities, and long-term monitoring of natural resource populations as well as the affected human populations.

What Can Be Done About the Remaining Oil?

In addition to funding studies to identify the locations of the remaining lingering oil through modeling and field sampling, the Council also continued to fund studies designed to determine what, if anything, could be done to restore the habitats where the oil occurs. The following studies have now been completed and reports are available at the links below.

  • A 2007 Project, Factors Responsible for Limiting the Degradation Rate of Exxon Valdez Oil in Prince William Sound Beaches, identified the factors that have slowed natural removal of the oil.
  • This was followed with a 2009 study, Identifying and Evaluating Candidate Bioremediation Technologies, that funded additional field work to extend the 2007 study above to determine if oxygen availability or nutrient (or both) in the lower beach layer are below concentrations needed for degradation of lingering oil residues to occur.
  • A publication in 2010 evaluated the potential for biodegradation of Exxon Valdez oil in the laboratory (Venosa et al., 2010). This study showed that more than 80% of the total polycyclic aromatic hydrocarbons, a toxic fraction of oil, could biodegrade within six months if the environment contained enough dissolved oxygen and nutrients. Pore-water chemistry measurements and modeling (Boufadel et al., 2010) demonstrated that oil biodegradation was being limited by a lack of nutrients, but the main finding was that the dissolved oxygen concentration in the groundwater measured in the oiled pits was so low that biodegradation could not occur (Boufadel et al., 2010).
  • In 2011, the Council funded a project that included pilot tests of candidate bioremediation technologies. Bioremediation techniques were tested in 2011 at four sites with lingering oil in PWS, using solutions of dissolved oxygen and nutrients to accelerate oil biodegradation.
  • In 2015, the project Lingering Oil in Prince William Sound, Alaska - Update, determined the best methods and their costs for implementing restoration of the lingering oil habitats. The Report identifies the site locations with moderate and heavy amounts of subsurface oil in PWS, determines the best technique for restoring each site, and provides estimates of the costs to implement the most suitable technique. During the evaluation, some sites were excluded for environmental concerns, the relatively small size or thickness of the patches, unsuitability of the site due to steep, rocky rubble or very large boulders, where the known toxicity was low, or where the pit was only moderately oiled and isolated in the upper intertidal zone away from other oiled areas. While 63 sites were identified in the report as potential candidates for restoration from a technical point of view, only nine of those beaches may be suitable for the application of bioremediation techniques and of those nine, five are known sites and four are model-predicted sites. The remaining 54 sites are thought to be suitable only for manual remediation. The report does not address the environmental detriment or the potential benefits of undertaking active restoration at these sites.

Current efforts to monitor select sites for the presence of lingering oil are included as part of the ongoing EVOSTC Long-Term Monitoring Program (Gulf Watch Alaska). Continued monitoring of these sites is intended to provide data on the quantity of oil remaining and to assess the weathering state through time. Because of the slow degradation rate, oil sampling is scheduled once every five years, with the first monitoring started in summer 2015. Additional monitoring related to the effects of lingering oil on wildlife is not warranted at this time, given the more recent findings of recovery of injured species.

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