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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop 3 Short- and Long-Term Effects on Human Health The Gulf of Mexico oil spill’s impacts are wide-reaching and will likely have long-lasting effects on the physical, psychological, social, and economic health of populations in the affected regions. The second component of the Department of Health and Human Services’ (HHS’) charge to the Institute of Medicine (IOM) was to review current knowledge and identify knowledge gaps regarding the wide range of effects on human health as a result of exposure to oil, weathered oil products, dispersants, and environmental conditions such as heat. Panelists considered both short-term (e.g., respiratory) and long-term (e.g., neurological) outcomes; both physical and psychological effects of exposure; both physical stressors (e.g., heat stress and fatigue) and chemical stressors (e.g., the oil and dispersants); and potential health effects in both the general population and among children and pregnant women specifically. The goal was not to examine comprehensively all that is known about the spill’s potential effects on human health. Instead, its goal was to consider which potential adverse effects to include in surveillance and to identify gaps in knowledge that could inform future surveillance programs. This chapter summarizes the panel discussions and question-and-answer periods that occurred during this session. Two separate panels discussed the risks that the oil spill poses to the short- and long-term physical and psychological health of individuals within the Gulf region as a result of the oil spill. Although this section divides speaker presentations into the general categories of physical and psychological health effects, many speakers over the course of the workshop recognized that the health of an individual and population is multidimensional and that physical, psychological, social, and economic factors interact to create an overarching state of health.
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop POTENTIAL SHORT- AND LONG-TERM PHYSICAL EFFECTS Oil spills and related clean-up efforts can pose numerous hazards to the physical health of individuals and communities. Nalini Sathiakumar quickly recapped some of the potentially hazardous chemicals and conditions associated with oil spills and provided a broad overview of the types of physical health outcomes that have been linked to specific hazards. Citing previous oil spill studies, she argued that currently available data can provide important information on risks of acute toxicity symptoms, genotoxicity, endocrine toxicity, and injuries, as well as the impact that proper use of personal protective equipment can have on reducing specific symptoms. Peter Spencer expanded on Sathiakumar’s overview by focusing on how exposures to select hydrocarbons in crude oil, including aromatic but also other types of hydrocarbons, can have chronic, neurotoxic effects on human health. He emphasized the transient nature of these effects in humans based on data from occupational exposure concentrations. In addition to chemical toxins, another major hazard (and, in some places, the hazard of greatest concern) is heat. Turning his attention to workers and volunteers, Thomas Bernard described the well-known effects of heat stress and fatigue, but stated that additional information was needed on the cumulative effect of prolonged, daily exposures. He noted that the effects of heat stress and fatigue were easy to identify and manage. In discussing the effects that certain chemicals can have on human reproduction and child development, Brenda Eskenazi described mechanisms by which chemical exposures can affect a child before conception, during gestation, and after birth. Drawing from non-oil-spill studies, she explored the types of health outcomes that could be monitored in a surveillance system, identified various sources for immediate biomonitoring activities, and explained the importance of adhering to the precautionary principle when working with pregnant women and children. Finally, Irwin Redlener focused on child physical and psychological development and health, describing the crucial characteristics that make children uniquely vulnerable to short- and long-term adverse health effects stemming from the Gulf oil spill. He identified several activities that he thought would be important to include in a child health surveil-
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop lance system (e.g., biospecimen banking and monitoring the onset of new emotional or behavior symptoms). Short-Term Physical Effects Nalini Sathiakumar, University of Alabama, Birmingham The Gulf oil spill and its related response efforts pose various hazards to individuals, which can increase the risk of adverse health outcomes, including acute toxicity and physical injuries. Although data are limited, there is consistent evidence that exposure to oil and related response activities are associated with short-term health effects. Nalini Sathiakumar began with an overview of potentially hazardous chemicals and conditions related to the Gulf oil spill. Among these are exposures to volatile organic compounds (VOCs), polyacylic aromatic hydrocarbons (PAHs), heavy metals, and dispersants. In addition, there are physical hazards associated with noise levels, sun exposure, heat stress, injuries, and ergonomic stressors. Studies of the Effects of Previous Oil Spills on Physical Health Much of the information about the short-term physical effects of exposure comes from studies of seven supertanker oil spills since the 1960s (Aguilera et al., 2010). Sathiakumar summarized the results of studies for each of the oil spills, except the Exxon Valdez studies (which are covered later in the chapter in relation to Lawrence Palinkas’s presentation). Most of these studies were cross-sectional and investigated the short-term, physical effects of hazards stemming from the oil spills. The majority of these studies used standardized questionnaires to measure acute toxic symptoms and general health. MV Braer (United Kingdom, 1993). Campbell and colleagues (1993) studied community residents using general health questionnaires to identify major, acute toxicity symptoms within the first 2 days of exposure following the oil spill. The researchers found evidence of neurological, ocular, and respiratory symptoms but no significant differences in lung, liver, or renal function between exposed and unexposed populations. In a follow-up study, Campbell and colleagues (1994) found that the general health questionnaire symptom score of exposed individuals was signifi-
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop cantly higher than that reported by unexposed individuals after 6 months, although there was still no evidence of adverse effects on lung, liver, or renal function. In a separate study by Crum (1993) investigating lung function in children, results showed no deterioration in lung function at either 3 or 9 to 12 days following exposure. Finally, Cole and colleagues (1997) found no evidence of genotoxicity after a 1-year followup of participants from the community. Sea Empress (United Kingdom, 1996). In a study of 18- to 65-year-olds in affected communities, Lyons and colleagues (1999) found that exposed residents were more likely to report symptoms of acute toxicity, including neurological, ocular, and respiratory symptoms, than unexposed residents. An additional study by Gallacher and colleagues (2007) found an association between oil exposures and raised perceptions of risk. Nakhodka (Japan, 1997). Morita and colleagues (1999) found that clean-up workers reported increased acute toxic symptoms (primarily neurological, ocular, and upper respiratory symptoms) and physical injuries (lower back pain) compared to the control group. The researchers also reported that, although 100 percent of clean-up workers used gloves, only 87 percent of the women and 35 percent of the men used masks, and less than 30 percent used protective eyewear. Erika (France, 1999). In a cross-sectional study of clean-up workers and volunteers, Schvoerer and colleagues (2000) identified neurological, dermal, ocular, and respiratory symptoms, as well as lumbar pain, in individuals involved in clean-up activities. The study identified duration of cleaning as a significant risk factor for an increase in lumbar pain. Prestige (Spain, 2002). Suarez and colleagues (2005) and Carrasco and colleagues (2006) investigated differences in reported toxicity symptoms between seamen and other types of workers, including bird cleaners, volunteers, and paid workers. Both studies found that toxic symptoms were higher among seamen than other types of workers, but Carrasco and colleagues also found that training about personal protective equipment (PPE) reduced the risk of toxic symptoms. Additionally, both studies found that injuries (e.g., bruises, deep wounds, sprains, fractures) were greatest among bird cleaners. The 2005 study also found a significant increase in the risk of injury for individuals that worked 20 or
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop more days. A separate study by Zock and colleagues (2007) recorded that the duration of clean-up activities was positively correlated with the risk of lower respiratory tract symptoms. These same studies also found increased levels of aluminum, nickel, and lead but decreased levels of zinc in blood samples from exposed individuals. In studies that focused on genotoxicity,1 Laffon and colleagues (2006) found that clean-up workers had greater DNA damage, but not cytogenetic damage, related to time of exposure. Pérez-Cadahía and colleagues (2006) also found a significant increase in comet assay in clean-up workers, indicating genotoxic damage, which was not affected by PPE use. Tasman Spirit (Pakistan, 2003). In a cross-sectional study of exposed residents, Janjua and colleagues (2006) found moderate to strong associations between proximity to the spill site and toxic symptoms. In a 2008 study of community residents and vendors, Khursid and colleagues found slightly elevated levels of lymphocyte and eosinophil levels among exposed populations. In a questionnaire about general health symptoms among clean-up workers, Meo and colleagues (2008) found a higher prevalence of ocular and respiratory symptoms compared to individuals not exposed to clean-up activities. In 2009, Meo and colleagues used a spirometer to identify a significant reduction in lung function among clean-up workers, but found that lung function improved when workers were removed from the polluted environment. Summary of Results Previous studies provide important lessons about acute toxicity symptoms, genotoxicity, endocrine toxicity, injuries, and PPE usage. Tables 3-1 and 3-2 describe categories of acute toxic effects associated with exposure to crude oil and to oil dispersants, as presented by Sathiakumar. Sathiakumar stated that acute toxic effects are associated with exposure to VOCs and oil dispersants, which can enter the body through the lungs, skin, or other membranes.2 The fumes are absorbed by the 1 Blanca Laffon described studies of genotoxicity and endocrine toxicity related to the Prestige oil spill (see Chapter 1). 2 As Edward Overton and John Howard explained (see Chapters 1 and 2, respectively), these VOCs are most heavily concentrated in areas near the spill site and can increase the risk of acute toxic effects.
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop skin or external membranes or inhaled through the mouth and nose and have been associated with disorders of the skin and mucus membranes. Additionally, ingestion of benzene and toluene is associated with neurological symptoms, nausea, vomiting, and diarrhea, stated Sathiakumar. Although not all studies measured particular exposure levels, among those that did, hydrocarbons were below occupational safety levels, levels of benzene did not exceed threshold limit values, and VOCs were within the range observed in urban environments, according to Sathiakumar. In communities living in the vicinity of the oil spills, even after controlling for preexisting allergies and medical conditions, there was consistent evidence of acute toxic effects (mainly neurological, ocular, and respiratory but not dermal) among exposed residents. However, these effects appear to be transient, said Sathiakumar. Biochemical tests for lung, kidney, and liver function were within normal levels both immediately and 6 months after the spill, and children’s respiratory function was within the normal range. In the context of genetic and endocrine toxicity, Sathiakumar referenced an earlier presentation by Blanca Laffon (see Chapter 1), which indicated some genotoxic damage in workers involved with oil spill clean-up activities. TABLE 3-1 Categories of Acute Toxic Effects Associated with Human Exposure to Crude Oil Chemical Route of Exposure Symptoms* VOCs (ethylbenzenexylene) PAH Dermal (contact) Skin/mucous membranes: erythema (redness), edema (swelling), irritation, dermatitis (rash, blisters) VOCs (benzene, ethylbenzene, xylene) Inhalation (air) Dermal (contact) Ocular (eyes): redness, soreness, watering, itching VOCs (benzene, ethylbenzene) Inhalation (air) Respiratory: cough, throat irritation (dry, scratchy, sore), shortness of breath, wheezing VOCs (benzene, toluene) Inhalation (air) Neurological: nausea/vomiting, headache, dizziness, irritability, confusion, weakness of extremities *Symptoms more pronounced in sensitive individuals.
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop TABLE 3-2 Categories of Acute Toxic Effects Associated with Human Exposure to Oil Dispersants Chemical Route of Exposure Symptoms* VOCs Ingestion (food, water) Gastrointestinal tract disturbances: transient nausea, possible vomiting, and self-limiting diarrhea 2-butoxyethanol, Petroleum Distillate (oil mist) Dermal (contact) Skin/mucous membranes: irritation of skin 2-butoxyethanol, Petroleum Distillate (oil mist, aromatic hydrocarbons) Inhalation (air) Dermal (contact) Ocular (eyes): watering, itching 2-butoxyethanol Petroleum Distillate (oil mist, aromatic hydrocarbons) Inhalation (air) Respiratory: cough and throat irritation *Symptoms more pronounced in sensitive individuals. Among clean-up workers, the studies found consistent evidence of acute neurological, ocular, respiratory, and dermal symptoms. Seamen showed more toxic symptoms than other types of exposed workers, such as paid workers and volunteers. However, in studies that measured VOC levels, VOC concentrations were highest in the volunteer environments. In the studies that found an association between reduced lung function and proximity to oil spill sites, the reduction was transient and improved in workers who were removed from the polluted environments. A few studies also analyzed the effect that use of PPE had on the reporting of acute toxicity symptoms. Results indicate that PPE usage (especially protective eyewear) was less than optimal. However, proper education about PPE was associated with increased PPE usage and workers reporting fewer symptoms. Unfortunately, PPE usage did not affect genotoxicity.
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop In addition to risk of harm from chemical exposures, there are physical hazards such as noise levels, sun exposure, heat stress, injuries, and ergonomic stressors. Table 3-3 lists possible risk factors and potential adverse outcomes that oil spill response workers could experience. In the studies that Sathiakumar described, researchers found significant differences in toxicity symptoms reported by seamen and other workers, including bird cleaners, volunteers, and paid workers. Bird cleaners were at greatest risk of injuries such as bruises, deep wounds, sprains, and fractures. Clean-up workers and volunteers were also at risk for developing back pain. One study identified working 20 or more days as a risk factor for worker injury. Although these studies provide valuable information about the types of health outcomes that may be appropriate for surveillance activities related to the Gulf oil spill, Sathiakumar described some methodological limitations that should also be considered. First, in addition to relatively small sample sizes and low rates of participation within affected populations, most of the past studies on short-term effects of oil spill exposures were cross-sectional. Because cross-sectional studies compare participant groups at only a single point in time, it is difficult to establish a temporal relationship between exposure and outcome. Second, with few exceptions, studies did not systematically monitor for exposures to specific chemicals. Instead, researchers established surrogate measures of exposure, such as an individual’s proximity to the spill site, location of residence, and the type and duration of operation for clean-up workers. Finally, there was no long-term follow-up of high-risk groups for either exposure or outcome assessment. TABLE 3-3 Potential Physical Injuries Related to Oil-Spill Response Efforts Possible Risk Factors Potential Adverse Outcomes Slippery or uneven working surfaces Slips, trips, and falls Use of tools, equipment, and machinery, working with wild animal (birds, fish) Injuries Strenuous work schedules, heavy physical workload, long duration of work Fatigue and lumbar pain Exertion, hot environment Heat-related health conditions
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop Heat Stress and Fatigue Thomas E. Bernard, University of South Florida The acute health effects of heat stress and fatigue are well known, stated Thomas Bernard. Unlike chemical stressors, there is no uncertainty about the effects of heat exposure—at least on a daily scale. Exertional heat stroke is the primary health concern for individuals exposed to intense heat because it can lead to fatalities. More common types of adverse health effects include heat exhaustion, which is less critical. Other acute heat effects include fainting and cramping. Exposure to intense heat can also affect individual behaviors. In fact, heat stress near occupational exposure limits is associated with a 50-75 percent increase in the frequency of unsafe behaviors when compared to a “thermally comfortable environment,” said Bernard. In unacclimatized individuals, the risk is even greater. As one would expect, increases in risky behaviors are associated with increases in acute injuries and musculoskeletal disorders. Despite a strong understanding of how limited exposure to heat stress can affect the health of individuals, said Bernard, more information is needed on the cumulative effects of exposure to extreme heat or “heat fatigue.” Understanding heat fatigue is especially important in the context of the Gulf oil spill where people are working 12 hours a day each day of the week. Borrowing from work-physiology models and studies of military recruits and the general population during documented heat waves, Bernard stated that repeated exposures to heat stress also increase the occurrence of injuries and place more strenuous demands on the cardiovascular system. Studies of the general population during documented heat waves may also provide additional endpoints to measure heat fatigue. Fortunately, the adverse effects of heat are quickly observable and readily reversible, which makes the Gulf oil spill a good opportunity to improve our understanding of the cumulative effects of heat stress and heat fatigue, Bernard remarked. It is important to carefully classify heat disorders through the use of a diagnostic protocol. Personal physiological monitors can capture information about the physical strain on workers. Additionally, to establish a causal linkage between health outcomes and heat, records logging the exact hours worked, including rest cycles, should be gathered, said Bernard.
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop Certain policies and procedures exist to limit substantially the risks for occupational heat stroke in workers, and the Gulf oil spill management and supervision systems are highly adaptive, changing work practices daily in reaction to the heat stress, observed Bernard. However, the assumptions underlying these policies and procedures may not adequately account for conditions in the Gulf of Mexico, Bernard asserted. When discussing heat stress, experts tend to assume that the worker population is healthy, acclimated, stable, and experienced with heat stress. In the affected Gulf regions, oil spill response workers are not being introduced slowly into a stable workforce, but are instead recruited all at once. Consequently, there are not enough experienced workers to teach newer workers about heat stress, putting new workers at greater risk of heat stress. Experts also tend to assume that the heat-exposure control measures that have evolved over time are generally effective, said Bernard. However, certain barriers may prevent workers from taking adequate precautions to protect themselves from the adverse effects of heat stress and fatigue. Possible communication or language barriers can prevent adequate and timely explanation of risks. Workers may also underestimate the risk associated with their jobs—believing that, because they work in familiar heat environments, occupational exposure limits are too conservative. Although Bernard observed that the Gulf oil spill management and supervision system appears “highly adaptive,” he also suggested that bottom-up communications, such as social marketing, could improve risk communication, better ensuring the recognition and treatment of serious adverse health outcomes, such as heat stroke. Exposure to Hydrocarbons in Oil and the Potential for Chronic Neurotoxic Effects Peter S. Spencer, Oregon Health & Science University, School of Medicine The potential of any given chemical to produce chronic or long-latency toxic effects on health varies by chemical structure, which can change over time, and by dose and duration of the exposure. Peter Spencer began by observing that, of the thousands of chemical structures in crude oil described by Edward Overton, only a very few of these structures have been tested individually for their toxic potential. The ability to study the biological effects of chemical mixtures is limited.
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop After mentioning the acute, reversible effects on brain function of volatile petroleum chemicals, Spencer focused on the molecular mechanisms leading to chronic neurotoxicity and carcinogenesis resulting from exposure to certain hydrocarbons in crude oil. Importantly, the ability of petroleum chemicals to affect brain function in the short term does not necessarily translate to long-term adverse health effects involving the nervous system. Much of what is known about the neurotoxic potential of chemicals in crude oil has been obtained largely from the administration of large chemical doses to laboratory animals in experimental settings. Additionally, because the underlying mechanisms for short- and long-term effects may be entirely different, the presence of acute health effects, such as headaches and dizziness, may or may not accurately predict the development of long-term effects. Moreover, scientists are just beginning to understand how certain genetic predispositions may affect the likelihood of adverse health effects as a result of specific chemical exposures. Of what is known about chemicals in crude oil, remarked Spencer, most of the data concern hydrocarbons, particularly the straight-chain, low-molecular compounds that evaporate very quickly (the alkanes). Noting the reversible short-term effects of alkane exposure (e.g., dizziness and headache), also described by Sathiakumar, Spencer stated that prolonged exposure to certain alkanes (e.g., n-hexane) also had the potential to produce long-term neurotoxic effects associated with nerve fiber degeneration. For example, some workers in industrial settings who were exposed for very long durations to significant concentrations of certain alkanes have developed peripheral neuropathy, which involves an insidious, gradual onset of changes in sensation and muscle weakness in the feet and hands that ascends the legs and arms. Fortunately, once the exposure ceases, the disease may advance to some degree but then slowly regresses to almost complete recovery with a few persistent effects, stated Spencer. However, recent laboratory rodent studies3 found that damage to the central nervous system was only very poorly repaired and that new types of neurological deficits may appear even after recovery of peripheral nerve fiber function. One laboratory proposed that exposure to particular alkanes may cause late-onset Parkinsonism in rats, but those results have not been replicated. 3 Spencer noted that laboratory experiments involving model organisms usually involve high levels of exposure (i.e., not human exposure levels in real-world settings).
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop Cohen ultimately suggested several endpoints and a research design that could be incorporated into a surveillance or monitoring system to monitor psychological stress related to the Gulf oil catastrophe. Cohen suggested measuring perception of stress and/or threat, along with feelings of depression, anxiety, and anger; health practices that are also good indicators of stress, including sleep quality, diet, physical activity, height and weight, smoking, alcohol and drug use; and adherence to medical regimens. Cohen also suggested some endpoints related to disease outcomes, such as the presence of depression, anxiety, and post-traumatic stress disorder; the incidence of cardiovascular disease; markers of disease progression among the chronically ill; and the use of health care. As part of the research design, Cohen proposed longitudinal, long-term, and individual follow-up studies to assess the progression and exacerbation of chronic diseases, with a special emphasis on mental health. Psychological Impacts of Oil Spills: The Exxon Valdez Disaster Lawrence Palinkas, University of Southern California A number of studies have been conducted on the social and psychological consequences of the Exxon Valdez spill. Lawrence Palinkas was involved with one of the largest of those studies, the “Oiled Mayors” study. The study was conducted 1 year after the spill and combined ethnographic fieldwork in 22 communities with a quantitative survey of about 600 households. The researchers measured exposure based on responses to a series of questions about whether the household had used an area affected by the spill, participated in clean-up activities, and the like. Lessons of the Exxon Valdez Studies Palinkas’s studies found a number of psychological outcomes that were associated with the degree of exposure (Palinkas et al., 1993a). A 1993 study by Palinkas and colleagues examined the relationship between certain psychiatric disorders and exposure to the Exxon Valdez oil spill and its response activities. In this study, exposure was widely defined to include direct contact with oil, damage or property loss, and disruptions to social and economic activities. Figure 3-1 depicts a significant association between exposure and generalized anxiety disorder,
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop FIGURE 3-1 Prevalence of generalized anxiety disorder (GAD), post-traumatic stress disorder (PTSD), and levels of depressive symptoms (assessed using the Center for Epidemiologic Studies Depression [CES-D] Scale) in Exxon Valdez study respondents. NOTE: In this figure, comparison groups are defined by exposure levels and include varying numbers of participants (N). The figure lists the odds ratios and confidence intervals (C.I.) for high- versus no-exposure groups. SOURCE: Palinkas et al., 1993a. post-traumatic stress disorder, and depressive symptoms as reported by study participants. Widely defined exposures to oil spills and clean-up activities were also associated with increased use of mental health services, as indicated by an increase in the number of mental health visits to the Seward Life Action Council in Seward, Alaska, between July and December 1989 (compared to July-December 1988) (Impact Assessment, Inc., 1990). In addition to the psychological outcomes, Palinkas and colleagues detected significant associations between exposure and problems with alcohol and drug abuse and domestic violence (Palinkas et al., 1993b; Russell et al., 1996) (see Table 3-4), as well as declines in traditional social relations (Palinkas et al., 1993b; Russel et al., 1996; Palinkas, 2009).
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop TABLE 3-4 Impact of Exposure to Exxon Valdez Oil Spill on Domestic Violence and Alcohol and Drug Abuse Social Unit and Problem % High Exposed % Low Exposed % Not Exposed Community More Drinking* 56.8 4.4 5.0 More Drinking Problems* 45.3 32.5 6.9 More Drug Use* 50.4 43.2 6.8 More Drug Use Problems* 39.5 30.8 9.4 More Fighting* 40.5 32.3 3.5 More Fighting Problems* 33.9 27.7 4.8 Family and Friends More Drinking* 29.3 15.3 2.8 More Drinking Problems* 26.0 13.3 5.4 More Drug Use* 21.2 10.8 1.7 More Drug Use Problems* 19.4 9.1 1.5 More Fighting* 19.7 3.8 0.9 *Chi-square test for trend P < .0001. SOURCES: Palinkas et al., 1993b; Russell et al., 1996. Palinkas explained that the studies following the Exxon Valdez disaster were noteworthy because they were the first to document post-traumatic stress disorder without any loss of human life. As Redlener had described earlier with respect to what is happening now with the Gulf of Mexico oil disaster, it was the loss of a way of life and not necessarily the loss of life itself that is profoundly affecting individuals. Palinkas described several results of the research, as outlined in the following sections. The researchers found that not all individuals were equally vulnerable. The Alaskan Native population was one of the groups most vulnerable to the disaster’s traumatic consequences, as the native population not only relied on the affected areas for subsistence activities but also participated heavily in the clean-up activities (Palinkas et al., 2004). Other vulnerable populations included clean-up workers, women, and families and children. The researchers also examined the impact of exposure on children and found that increased exposure was associated with a decline in relations with other children in the community, difficulties sleeping, poor
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop school performance, anxiety upon hearing someone talk about the spill, bedwetting, problems with being left alone, fighting with other children, and difficulties getting along with parents and siblings (McLees-Palinkas, 1994). In some cases, these findings were similar to those in adults. One of the most interesting findings, Palinkas said, was the association between difficulty finding child care and post-traumatic stress disorder, anxiety, and depression in parents. Because psychological stress can lead to physiological changes and increased risks for chronic diseases, Palinkas and colleagues examined the impact of the Exxon Valdez spill on physical health. As with the psychological outcomes, researchers found that more-exposed individuals reported more heart disease, high blood pressure, diabetes, thyroid problems, cancer, asthma, ulcers, bronchitis, chronic coughs, and skin rashes (Impact Assessment, Inc., 1990). Applying Lessons Learned from the Exxon Valdez Studies to the Gulf Oil Spill Palinkas echoed other panelists’ recommendations to monitor populations particularly vulnerable to psychological stress. He mentioned previously traumatized populations, such as Hurricane Katrina victims, Vietnamese refugees, children and families, and under-served populations. Palinkas also singled out the need to monitor participants in clean-up activities, whose vulnerability stems from prolonged separation from their families, conflicts between those who did and did not accept clean-up jobs, and witnessing firsthand the ecosystem’s destruction. Palinkas also recommended the collection of particular types of data necessary to measure long-term mental health effects. Suggested measures included measures of mental health indicators, such as indicators for anxiety, depression, and post-traumatic stress disorder; social disruption; drug and alcohol use; child behavior; and qualitative data on individual-and community-level responses to the oil spill. Finally, as other panelists had done, Palinkas highlighted the possible influence of litigation on long-term data collection.4 Although the Exxon Valdez oil reached its maximum size within 56 days, the Exxon Valdez story did not end after 56 days. In fact, it continued for about 20 years, 4 Although HHS did not charge the IOM with investigating the effect of litigation on possible surveillance systems, the issue continued to emerge as an important research limitation.
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop until late 2009, when the U.S. Supreme Court ruled on compensation for damages. For many of the residents of the affected communities, the story continues even today. Ironically, the litigation itself has been a form of stress-inducing exposure that caused community conflict and prolonged uncertainty. QUESTIONS AND COMMENTS FROM THE AUDIENCE Is there a need for diagnostic protocols or clinical guidelines for mental health symptoms that front-line providers can use? Osofsky replied that such protocols and guidelines would be useful. Even well-trained volunteers and workers will experience medical or psychological problems. Individuals present in emergency rooms for respiratory, dermatological, cardiovascular, or other physical problems, and it can be difficult for professionals treating them to realize that such individuals may also have acute stress, depression, or other psychological problems that are compounding the expression of physical symptoms. The physical and psychological symptoms need to be treated together. There also needs to be some recognition that medical personnel may be experiencing secondary traumatic stress themselves. Later during the workshop, there will be discussions around ways to monitor populations and collect research data while moving forward. But what about providing care to the people who are being monitored or are participating in the research studies? For example, have there been efforts in the mental health field to ramp up services as data are collected? Osofsky replied that, while the Deepwater Horizon disaster has not interrupted services like Hurricane Katrina did, resources are nonetheless very limited and are only just being re-established. Is there reason to be concerned about a potential synergistic effect of heat and chemical exposure? Bernard replied such a concern is appropriate to the extent that anything that affects the central nervous system is probably going to affect the thermal regulatory center. And anything that affects the renal system
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop or other factors that affect fluids and electrolyte balance will likely influence the effect of heat exposure. Sathiakumar identified the relationship between chemical exposure, heat exposure, and behavior as being very important (e.g., if it is too hot to wear PPE, the risk of chemical exposure will increase). Osofsky added that individuals taking medications for mental health conditions will be much more vulnerable to heat exposure. Given that heat stress increases risky behaviors, is having well-motivated workers (workers who want to work quickly in the heat for a longer period of time to stop the oil from coming to shore) a problem? Bernard replied that particular attitudes can be a problem. It is important to have an effective heat stress management program in place to contain that enthusiasm so that workers protect themselves. Many clean-up workers have preexisting medical conditions that may put them at increased risk for heat stress. What guidelines or recommendations exist for screening these workers? Bernard replied that there are some risk factors related to impaired water balance, decreased cardiovascular capacity, or impaired thermal regulation (e.g., many drugs used to treat chronic disease affect thermal regulation). The problem with pre-screening is that there is no good test to identify who is going to be able to work in the heat, other than a history of having successfully worked in the heat. One approach is to review known risk factors with workers and submit letters with information on heat exposure to workers’ personal care physicians so that the workers can be properly guided. Do break periods need to vary by age? Bernard replied that heat stress is less age-related than it is fitness-related. In addition to previous heat exposure experiences, aerobic capacity is a good indicator of how well one will do in the heat. In any event, right now, breaks are extensive. For example, offshore workers receive 2-hour breaks for lunch in an air-conditioned facility.
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop Are biomarkers of exposure relevant to the general population, or are they relevant only for heavily exposed populations? The relevance of biomarkers appears to depend on which chemical compound is being monitored. Spencer replied that many biomarkers of exposure are developed as a consequence of experimental studies that involve studying high doses of exposure in laboratory animals; this is because limits in the duration of exposure possible in experimental settings requires that researchers increase the doses so that they can detect effects. The biomarkers that are identified in those circumstances have limited use in situations where the levels of exposure are low (i.e., most real-world human situations). On the other hand, Eskenazi stated that there are some sensitive biomarkers, such as those for benzene, that can be used to detect fairly low exposure levels. In fact, she and her colleagues have used biomarkers (in sperm) to measure changes in benzene exposure even within the U.S. permissible exposure limit. What are the neurotoxic effects of exposures to heavy metals (e.g., lead, mercury, cadmium)? As is the case with so many exposure pathways, there are many uncertainties (e.g., whether thresholds for effects are reached in realworld settings and whether other factors could be responsible for the observed effects). Spencer stated that many heavy metals can adversely affect neurologic function. As an example, he pointed to Minamata Bay, Japan, where industrial effluent containing mercury that had been released into the bay was converted into an organic mercury that then entered the marine food chain and caused profound neurologic damage in humans. For instance, children born to pregnant women who had consumed mercury-contaminated fish were born with abnormal brain structures and permanent brain dysfunction. But in order to answer the question in the context of the Deepwater Horizon disaster, he said that he would need to know the likely levels of exposure, as there are thresholds for the effects, and it is not clear whether they will be reached. Eskenazi stated that she was very concerned about heavy metals, noting that recent evidence indicates that even low levels of manganese may affect neuro-behavioral development in children. She suggested that lead levels in children in the Gulf region be screened to see whether there are any “pockets of elevation.”
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop Spencer also reminded the audience of the Gulf of Mexico “dead zone,” which Goldstein had mentioned, and the brevetoxins that naturally exist in the bivalve and molluscan shellfish inhabitants of the dead zone, which are responsible for the region’s “red tides.” He noted that brevetoxins can enter the food chain and cause both acute and chronic significant neurologic dysfunction. What are your recommendations for long-term monitoring of mental health? Most of the panelists agreed that relying on biomarkers to monitor mental health is not an effective strategy and that clinical monitoring of symptoms and the use of standardized mental health assessment tools would be much more useful. Specifically, Cohen replied that the use of biomarkers to measure stress (e.g., epinephrine or cortisol) are not useful in this situation, as the quality of available biomarkers is extremely variable and biomarker measures are sometimes not comparable across environments. He emphasized the importance of long-term monitoring for symptoms of anxiety and depression. He stated that Redlener agreed that biomarkers are not a practical means of monitoring changes to inform care, particularly in children, and emphasized instead the importance of clinical “psychomarker” monitoring—the monitoring of sleep difficulties, changes in behavior, difficulties interacting with siblings or peers, etc. Palinkas mentioned the Millennium Cohort Study, a large population-based study that emerged after the first Gulf War in response to concerns about Gulf War syndrome, as a good example of how standardized mental health assessment protocols and tools can be incorporated into the surveillance process in a timely manner and in such a way that the data can be used to inform policy and mitigate adverse health outcomes. The study was designed to identify both the long-term physical and mental health effects of deployment of military personnel, and it is beginning to generate substantive knowledge. Study participants respond annually either through mailed questionnaires or via a website to standardized instruments that assess health outcomes. If you or your family were living in the Gulf Coast area, what concerns would you have and what precautions would you take? Most of the panelists identified the need for mental health services and a trusted source of information as the most pressing concerns.
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop Redlener replied that his principal concern would be to find out where he could get information that would help him understand the consequences of the disaster for his family. Residents want to know what the risks are with the food supply, the water supply, etc. He said, “There are many, many details of normal, day-to-day living for which people want answers.” Eskenazi agreed with Redlener that she would want a trusted source of accurate information. She described how several studies have shown that often one of the largest outcomes following disasters is distrust of authority. Palinkas agreed. He said that trusted local authorities serve not only as sources of accurate information but also as mechanisms for maintaining a sense of stability in the affected communities. Having faith that local governments are managing certain components of the response (e.g., employment issues) could alleviate some of the residents’ concerns that are causing stress. However, he said that one of his biggest concerns would be the adequacy of services. Following Hurricane Katrina, the health care and social-services sector was among the hardest hit sectors. That sector is only just beginning to recover, and now there are increased demands for psychologists, psychiatrists, and other mental health and social-services professionals. Cohen expressed concern about the potential loss of the very strong sense of community and culture that exists in the Gulf region and the psychological stress caused by that loss. Eskenazi also said that, if she were a parent of a young child, she would carefully watch the Environmental Protection Agency (EPA) air-monitoring website. She would also be concerned about feeding her children local fish, although she acknowledged that her concern was a gut-level response and was not based on evidence. Spencer replied that he would primarily be concerned about the quality of food. What can be done today with the information already available to mitigate the adverse health consequences of exposure? Based on lessons learned from the Exxon Valdez spill and Hurricane Katrina, Palinkas and Redlener both identified the need to establish a way for the community to feel in control of the situation. Palinkas replied that, based on the Exxon Valdez experience, the manner in which the cleanup was conducted was one of the biggest sources of stress. Many people in the communities felt a loss of control, in much the same way that Cohen said happens during stressful situations, because the Exxon Valdez contractor approached communities from the outside and offered
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop wages that exceeded what was otherwise available to workers in those communities, which caused some community conflict. For example, citizens who would otherwise generate income through child daycare made much more money cleaning oil off the rocks, which led to very limited child daycare services for the community. Cohen said that one way to mitigate adverse effects is through local control—not only with respect to compensating local residents but also with respect to including residents in clean-up activities without over-whelming community resources and the physical and mental capabilities of the residents. Redlener reflected further, but from a different perspective, on the need for an immediate sense of control. He replied that it is essential that residents immediately know who is in control and where they can access information on a daily basis to help them make decisions (e.g., about whether it is safe to let their children play outside). Many of the most affected families were medically under-served and disadvantaged before the oil disaster, and their access to the usual forms of health care information is extremely limited. Affected families need to be provided a sense of structure and cohesion, as well-trusted messengers, to help them get through what is a very stressful time. The failure to provide these services will exacerbate problems that already exist. Other panelists identified the need to develop effective communication strategies for vulnerable populations. Specifically, Eskenazi emphasized the importance of focusing on pregnant women. Some studies have shown that some of the mental health consequences are greater in women than in men, and pregnant women are particularly vulnerable because they are not just protecting themselves but also their developing fetuses. She asked how pregnant women can obtain accurate information from a trusted source about the risks (e.g., of eating seafood)? Spencer agreed with Eskenazi and remarked that chemical exposure during development can potentially cause permanent changes to the brain and other parts of the body. He emphasized the importance of considering the other end of the aging spectrum as well. Older adults are uniquely vulnerable to chemical exposure because of weight loss, loss of liver metabolism and renal excretion functions, etc. Spencer also discussed variation in susceptibility to the adverse effects of exposure. Specifically, he reminded the workshop that the federal threshold levels that have been established to protect health are based on “protection of the majority but not the totality of the population.” Scientists are increasingly recognizing that there are individual genetic susceptibilities to certain exposures, one example being heat
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Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop stress; there is a genetically based loss of muscle function that has been shown to be associated with increased susceptibility to heat stress. Spencer emphasized the need to determine whether people involved with clean-up are more susceptible to heat stress or other risks because of their genetic make-up or other factors.