The Use of Dispersants in Marine Oil Spill Response (2020) / Chapter Skim
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4 HUMAN HEALTH CONSIDERATIONS
4 HUMAN HEALTH CONSIDERATIONS
Pages 115-140
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From page 115... ...
. Overview of Human Health Considerations During and After Oil Spills While the environmental consequences of marine oil spills has been an important topic of investigation since at least the Torrey Canyon and Santa Barbara oil spills in 1967 and 1969, respectively, research on the direct and indirect human health impacts of oil spills is relatively recent, whether dispersants were used or not, with some research conducted following the Exxon Valdez and Sea Empress oil spills but much more initiated after the Prestige oil spill in 2002 (Goldstein et al., 2011; Laffon et al., 2016; see Table 4.2 later in this chapter)
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From page 116... ...
A spill can also have an extensive effect in that the presence of surface sheen or of PAHs in seafood can result in prolonged closure of fisheries, which may contribute to secondary effects on community psychological and socioeconomic health and well-being. Worker health and safety is a primary concern during spill response in the United States, and community health, safety, and wellbeing have also received attention after more recent oil spills.
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From page 117... ...
For future spills, downwind ozone formation might need to be taken into account during summer months, particularly in regions that are exceeding, or close to exceeding, the primary air quality standard for ozone. Results of modeling of subsea use of dispersants during the DWH spill response suggest a reduction in the VOC inhalational exposure pathway by enhancing the formation of small oil droplets and increasing the dissolution of VOCs within the water column, which also could potentially decrease downwind ozone formation (Gros et al., 2017; see Chapter 2)
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From page 118... ...
There would be value in expanding and improving protocols for measuring exposure during a response for oil spill workers (with potential dermal, ingestion, and inhalation exposure routes associated with dispersant application and oil spill response activities) as well as for residents in general (via dermal, ingestion, and inhalation exposure routes from beach activities and/or consumption of seafood)
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From page 119... ...
Two studies of DWH response workers have attempted to disentangle the direct effects of dispersants from other worker health risks. While both studies have noted adverse effects associated with self-reported dispersant exposures, both have significant problems in validating the accuracy of the workers' identification of dispersant exposures (see below)
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From page 120... ...
and may be relevant for predicting mammalian toxicity. For comparison, the committee notes that burning of surface oil, another method used in oil spill response, produces pyrogenic PAHs or unsubstituted parent compounds, whereas PAHs found in crude oil are more likely to be alkylated.
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From page 121... ...
Additionally, comparison of dispersant toxicity metrics with those of cleaning agents used in the decontamination of vessels by oil spill response workers may be useful, because surface washing agents, like dispersants, contain surfactants and solvents. As an example, ecotoxicity of cleaning agents used in decontamination, such as PES-51 and Simple Green, has been evaluated by EPA (EPA, 2018)
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From page 122... ...
122 TABLE 4.1 In Vitro LC50s (ppm) for a Variety of Dispersant Formulations and Mammalian Cell Types Exposure Corexit® EC9500A Corexit® EC9527A Corexit® 9550 ZI-400 Dispersit SPC 1000 Nokomis 3-F4 Nokomis 3-AA Sea Brat #4 SAF-FRON GOLD JD 2000 Reference Cell Line Time Bandele et al., Hep2G 72 hr 275 250 -- > 400 -- -- -- -- -- -- 2012 Shi et al., 2013 BEAS-2B 24 hr 200 100 > 300 -- -- -- -- -- -- -- Zheng et al., 2014 Multiple w/FBS 48 hr 150 ≥ 200 -- -- -- -- -- -- -- -- -- (w/out FBS)
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From page 123... ...
and the Deepwater Horizon Oil Spill Coast Guard Cohort Study As part of an extensive health study of DWH response workers, investigators from the National Institute of Environmental Health Sciences (NIEHS) and collaborative programs attempted to specifically disentangle the impact of potential exposure to dispersants on the previously reported respiratory, dermal, and eye irritation symptoms (McGowan et al., 2017)
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From page 124... ...
Each USCG member involved in the oil spill response activity was asked to complete an exit survey, including exposure-related information and symptoms. Using a five-point Likert scale, respondents were asked to quantify how often they were exposed to crude oil/oily water or to dispersants.
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From page 125... ...
well past the time that this biomarker would persist in the body following the cessation of response work. Next Steps for DWH Analyses and Considerations for Future Work The information from studies of DWH response workers suggests the need for continued diligence in avoiding dispersant exposure during any future use.
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From page 126... ...
The two recently released DWH worker health studies have suggested that exposure to dispersants contributes to the symptoms of oil spill responders, particularly of the respiratory tract. If confirmed after more detailed exposure assessment, or in subsequent studies of response workers, it is important to determine whether longer-term consequences will follow, as has occurred, for example, in the 9/11 response group (Mauer et al., 2010)
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From page 127... ...
Epidemiological Evidence from Studies of Other Previous Oil Spills Previous Oil Spills (Exxon Valdez, MT Braer, Sea Empress, MT Erika, Prestige, MT Hebei Spirit) Studies evaluating human health outcomes during and following previous oil spills have been reviewed (Aguilera et al., 2010; Goldstein et al., 2011; Gräbsch, 2016; Laffon et al., 2016)
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From page 128... ...
Human Health and Type of of Chemical Outcomes Oil Spill Year Oil Released Dispersant Used Evaluated Methods Findings References Oil spills in which chemical dispersants were used and human health outcomes were evaluated Exxon Valdez 1989 37, crude oil Aerial Mental health Cross-sectional and Increased generalized anxiety Arata et al.
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From page 129... ...
biomarkers association with physical symptoms, oxidative stress biomarkers increased and correlated with PAH exposure biomarker 1 year after cessation of response efforts Deepwater 2010 500-750, LA ~4,050 surface Acute illness Longitudinal, survey See above detailed summary See summary above Horizon sweet crude ~2,900 subsea symptoms, VOC oil exposure Oil spills in which chemical dispersants were not used and human health outcomes were evaluated Erika 1999 20, heavy N/A Acute illness Cross-sectional survey No control group Schvoerer et al., 2000 fuel oil symptoms Prestige 2002 63, heavy N/A Acute illness and Cross-sectional survey, Increased headache, sore throat, Carrasco et al.
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From page 130... ...
. The additional step of developing methods for dispersant detection during an active emergency response resulted in a lack of baseline information and estimates of exposure during the spill; this could be avoided by moving this activity to the preplanning phases of oil spill response efforts.
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From page 131... ...
. Calculated LOCs have varied considerably across oil spills primarily driven by differences in the choice of risk level and exposure duration (Gohlke et al., 2011)
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From page 132... ...
Moving forward, as the body of evidence becomes more refined, risk-based criteria for fisheries reopenings should become more consistent in the evaluation of health risk associated with chemically dispersed oil and inclusion of seafood contamination risks into integrated models. Additional Considerations in Comparing Toxicity Across Response Methods The ultimate decision to use dispersants will be made by an agency different from the one with statutory responsibility for evaluating seafood safety and closure decisions.
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From page 133... ...
-- suggest that VOC exposures can affect coordination and judgment in ways that might increase the likelihood of injuries and accidents among response workers. Benzene is a known human carcinogen present in crude oil.
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From page 134... ...
In the DWH response, one rationale for subsea dispersant injection (SSDI) at the crude oil release point and surface application at the wellhead was that they would increase dispersion and enhance dissolution of the more volatile portion of the crude within the water column, thereby reducing potential VOC exposure and fire hazards for response workers at the surface near the wellhead (USCG, 2011)
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From page 136... ...
This lack of detail in responder health surveillance is not specific to oil spill response. The National Response Team Emergency Responder Health Monitoring and Surveillance Technical Assistant Document dated January 26, 2012, notes that even though lessons learned from previous emergency events continue to be applied, "there are still significant gaps and deficiencies in health monitoring and surveillance for emergency response workers." The report further points out a need "for a coherent, comprehensive approach to protecting these groups of workers and for detailed, practical guidance on implementing such an approach." Oil spill response carries certain risk for workers, especially in the emergency response phase.
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From page 137... ...
Duration of Oil Spill Response Activities Several previous studies have characterized significant economic, psychosocial, and mental health effects during and after oil spills in coastal communities (see Table 4.2)
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From page 138... ...
For example, burning of a complex hydrocarbon mixture such as crude oil could lead to greater inhalational exposure to PAHs and benzene for the worker population. As discussed in the toxicological evidence section, the PAHs produced by combustion are somewhat different in chemical structure and in component mixture than are those naturally present in crude oil and likely have different toxicological properties.
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From page 139... ...
To that end, publication and ready availability of well-defined DWH worker health and safety statistics is needed. Exposure assessment and toxicological evaluation should recognize that response workers may not be from a healthy worker population and may not know how to minimize exposure.
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From page 140... ...
During the spill response following the DWH oil spill, the use of an unprecedented volume of chemical dispersant contributed to these effects. Furthermore, the publicity related to the lack of publicly available information on the chemical constituents of the dispersant formulations contributed to concerns.
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