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Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

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.

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

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-

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

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-

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

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

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

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.

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

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.

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

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.

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

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

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

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.

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

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.

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

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).

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

In addition to straight-chain compounds in oil, specific benzene derivatives may also produce peripheral neuropathy symptoms. Spencer and his colleagues demonstrated that compounds such as 1,2-diethylbenzene (1,2-DEB) and its metabolite 1,2-diacetylbenzene (1,2-DAB) are substantially more potent than specific straight-chain compounds in laboratory rats. In addition to being neurotoxic, 1,2-DEB and 1,2-DAB in high concentrations can produce a bluish discoloration in amino acids that can spread throughout the body. As the toxin travels throughout the body, the toxin reacts with the particular architecture of the nervous system, resulting in the degeneration of long, large nerve fibers. Although 1,2-DEB can exist in small concentrations in petroleum, no adverse effects have been documented in humans due to minimal exposure.

Spencer concluded by noting that a third class of hydrocarbons, the cycloalkanes (e.g., naphthenes), has attracted much less attention with respect to its potential human health effects. Certain polyaromatic forms have been associated with DNA damage and carcinogenicity, but these chemicals have not yet been identified in the Deepwater Horizon oil.

Human Reproduction and Child Development

Brenda Eskenazi, University of California, Berkeley


Chemical exposures before conception, during gestation, and after birth can affect a child’s health. Direct chemical exposures can occur to a fetus or a child across the placenta or by ingestion, inhalation, or dermal absorption. Overall, very little information is available for most of the chemical compounds in oil and for the chemical dispersants being used in the clean-up, said Brenda Eskenazi. This is especially true of chemical mixtures.

Children and fetuses are more vulnerable to adverse effects from chemical exposures because developing organs are more sensitive and less efficient at detoxifying and metabolizing chemicals, said Eskenazi. One study involving hundreds of children found that children under the age of 7 have insufficient enzyme levels to detoxify a particular pesticide (Holland et al., 2006; Huen et al., 2010), suggesting that the period of vulnerability for different chemical compounds could be lengthy. At least five studies investigating the effects of benzene exposure on children’s health identified association between residential proximity to gas stations (or repair garages using benzene) and childhood leukemia (Shu et al.,

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

1988; Steffen et al., 2004; Whitworth et al., 2008; Brosselin et al., 2009; Weng et al., 2010). Eskenazi also described studies of children in the United Kingdom, which found that exposures to chemicals from the MV Braer oil spill did not cause any deterioration in lung function at either 3 or 9 to 12 days following exposure (Crum, 1993).

A number of studies have also documented a broad range of potential effects on children as a result of in-utero exposures. In terms of exposure to benzene itself, some studies have shown associations with spontaneous abortion (Xu et al., 1998), neural-crest birth defects (Wennborg et al., 2005), decreased birth weight (Aguilera et al., 2009), and decreased head circumference (Slama et al., 2009). Another study found that exposure to benzene alone was not associated with lower birth weights, but rather that the interaction between benzene exposure and high stress that increased the likelihood of decreased birth weight (Chen et al., 2000). Eskenazi also described four studies that showed associations between PAH exposure and decreased birth length, birth weight, head circumference, and body weight of toddlers (Perera et al., 1998; Choi et al., 2006; Tang et al., 2006; Choi et al., 2008). Two studies revealed associations between airborne PAHs and DNA adducts (Perera et al., 2004; Wu et al., 2010). When present in maternal blood, such adducts have been linked to spontaneous abortions. However, Eskenazi repeated that PAH exposures may not be of greatest importance, citing previous speakers who stated that high concentrations of PAHs had not been found in Deepwater Horizon oil.

Chemical exposures in general can also have epigenetic transgenerational effects on future children. Eskenazi also described one scientific paper that explored the effect of oil spills on the health of pregnant women, finding only short-term eye irritation, headaches, and abdominal pain in pregnant women (Kim et al., 2009). However, maternal exposures to certain fungicides have been shown to cause low sperm counts in rats four generations removed (Anway et al., 2005). Paternal exposures to certain chemicals can also affect offspring, which is important because many of the Gulf oil disaster clean-up workers are fathers or future fathers, said Eskenazi. A growing body of evidence finds that paternal exposure to specific toxins can increase the risk of spontaneous abortion, birth defects, and aneuploidy syndromes (such as Down syndrome) in children. A 2010 study showed that fathers who had been exposed to workplace benzene had an increased risk of sperm hyperploidy, which could result in aneuploidy in offspring (Xing et al., 2010). Another study using a job-exposure matrix found that specific paternal exposures to

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

PAHs increased the likelihood of brain tumors in offspring (Cordier et al., 2004).

Drawing from What We Already Know and Have

Clearly, there is a great deal that we don’t know about the short- and long-term impacts of oil-spill-related exposures on single and multi-generational development, said Eskenazi. However, opportunities exist to learn from past disasters and to capitalize on specimens already available, especially if future research is community based. Eskenazi suggested that data from birth certificates can quickly provide useful information related to the effects of tracked exposures on newborn health. Researchers can also petition local health departments to add questions to birth certificates to help fill existing data gaps. For example, one study of pregnant women after the 2001 World Trade Center disaster found a much higher proportion of lower birth weight children and more females than expected (Eskenazi et al., 2007).

Eskenazi emphasized the importance of collecting biomonitoring data immediately. She reported that, immediately following a 1976 dioxin explosion in Italy, blood samples were collected. Although it was not clear at the time which chemical to measure, researchers were able to examine associations between exposure to that dioxin and adverse health outcomes a decade later. Eskenazi said that there are several “easy” ways to collect blood specimens for biomonitoring data. For example, health care providers collect blood samples as part of routine prenatal alphafetoprotein screening and as part of the newborn heel-prick test for phenylketonuria. In addition to blood, other biological materials could be used for biomonitoring, including urine, breast milk, amniotic fluid, and meconium (the first stools of the infant).

Finally, in discussing risk communication strategies that target pregnant women, Eskenazi stated that the precautionary principle should guide actions in the absence of complete information. Currently, pregnant women are referred to information posted on the Centers for Disease Control and Prevention (CDC) website, which advises pregnant women to “avoid areas where there are reports of oil reaching the shore” and other, specified activities (CDC, no date). Although the website states that “seafood that is unsafe will not be allowed in stores,” Eskenazi questioned whether additional precautions should be taken to protect

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

pregnant women and children from potential adverse health effects from yet-unidentified exposures stemming from the Gulf oil spill.

Impact of the Gulf Oil Spill Disaster on Children

Irwin Redlener, Columbia University


Children represent about 25 percent of the U.S. population, but they are an under-resourced and under-served population with respect to their special needs during and following disasters. It is not enough to simply extrapolate from research among adults. As Irwin Redlener said, children are not just “little adults.” Several unique anatomical, physiological, and behavioral characteristics make children a very different and special population to consider when evaluating the health effects of hazards related to the Gulf oil spill. Redlener described seven characteristics that make children uniquely susceptible to a wide range of adverse health effects:

  • Children live and breathe more closely to the ground. Consequently children may inhale greater concentrations of “heavier” toxic elements in the environment than do adults.

  • Children’s respiratory rates are more rapid than those of adults. Thus, children may have unique problems related to inhalation exposures.

  • Children have a large permeable skin-to-body mass ratio, which has implications for absorption of toxic materials through the skin.

  • Children routinely place hands and objects in their mouths, increasing the risks associated with ingestion of toxic materials.

  • Children take risks, so they are less likely to follow public health guidelines or act in a safe manner.

  • Children are dependent. Due to stages of physical and psychological development, children cannot always identify or choose when to avoid something harmful in their environment.

  • Children are highly susceptible to short- and long-term stress.

As a result of their unique characteristics, children are more susceptible to adverse outcomes related to the Gulf oil spill and its response activities. Children in particular high-risk groups, including low-income, disadvantaged, and asthmatic children, are at increased risk for exacer-

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

bating respiratory symptoms common in the general pediatric population. Inhalation-related symptoms, such as narcosis, tachypnea (rapid breathing), pneumonia, headaches, and other mild neurological symptoms, have already been documented. Redlener suggested that surveillance activities should also track dermatological conditions, aspiration syndromes, and a range of long-term, central nervous system consequences or malignancies that may result from exposure to crude oil products.

Psychological “toxic stress” is arguably the most significant health issue for children, according to Redlener. Children who are exposed to long-term, persistent stress without a strong mitigating parental figure can suffer a range of irreversible effects, including chronic medical conditions in adulthood. In fact, the well-being of children is directly related to the resiliency and stability of their parents, said Redlener. Hurricane Katrina is a recent memory and trauma for many children, and the Gulf oil spill is likely to increase the risks associated with stress and anxiety in children’s environments. When asked which was worse, Hurricane Katrina or the oil spill, one 15-year-old boy said:

This is way worse than Katrina. That was just a hurricane; that destroyed a lot, but we could rebuild and eventually come back to our homes. With the oil spill, we live with uncertainty, and most of us are afraid that this place we love will not come back. It will mean the end of our way of life. I don’t know what we’ll do—or how we’ll survive.

There are significant psychological and academic consequences associated with toxic stress in children. In fact, researchers documented elevated levels of anxiety and post-traumatic stress following the 2001 World Trade Center attack. Redlener also described unpublished studies (at the time of the IOM workshop) that found severe consequences related to persistent uncertainty, parental dysfunction, and severe economic stress following Hurricane Katrina. Seventy-five percent of children affected by Hurricane Katrina exhibited serious psychological issues. These children were four times more likely than children in the general population to have serious emotional disorders and two times more likely than children in the general population to be too old for their grade.

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
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Relevant Gaps in Scientific Knowledge

Redlener stated that significant gaps exist in our knowledge of potential adverse health effects of large-scale disasters in children. Insufficient evidence exists to indicate whether there will be long-term pathology related to persistent, high-level toxin exposures or psychological consequences stemming from prolonged periods of uncertainty or economic loss. Questions remain about the effects of multiple exposures to large-scale disasters, such as Hurricane Katrina, the recession, the Gulf oil crisis, and the possibility of another hurricane. Accordingly, there is a need to identify effective interventions for prevention and mitigation of trauma across populations, as well as identifying best practices for bolstering family resiliency, ensuring stability and access to health care and other essential services, and maintaining academic continuity in the face of large-scale disasters like the Gulf oil catastrophe.

Suggested Monitoring

Redlener recommended a particular approach to monitoring potential adverse health impacts of exposure to toxins and toxic stress. As part of surveillance activities, public health authorities should: (1) collect baseline clinical and laboratory assessments; (2) bank biospecimens; (3) monitor new onset of specific health concerns (e.g., breathing issues, headaches, abdominal symptoms); (4) monitor new onset of emotional or behavioral symptoms; (5) monitor cognitive, developmental, and academic status; and (6) monitor family and child “well-being” indexes.

Redlener concluded by emphasizing the critical importance of providing reliable information from trusted sources by engaging local authorities in risk communications strategies. Redlener said that he has observed a significant and widespread lack of trust in the federal or state governments or outside agencies. Citizens wanted to hear from their local authorities about whether or not parents should allow their children to swim, to play in the yard, and the like. A dearth of such information only adds to the anxiety.

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

POTENTIAL SHORT- AND LONG-TERM PSYCHOLOGICAL EFFECTS

As with the acute health effects of exposure, potential acute, chronic, and delayed mental health problems are just as important to consider as potential chronic physical health problems. Howard Osofsky described the immediate effects that the social, economic, and psychological stressors had on communities in the Gulf region following Hurricanes Katrina and Rita and noted that local residents and parishes were already reporting similar symptoms, such as depression, anxiety, and suicidal thoughts. Osofksy described some of the mental health data that he and colleagues collected after Hurricane Katrina and explained that they would continue to collect modified forms of these same data in the wake of the Deepwater Horizon disaster.

Sheldon Cohen described the different ways that the Gulf oil disaster may be producing the same type of psychological stress that other, more common events (e.g., job loss) cause; how psychological stress varies depending on how threatening an event is perceived to be and how well a person is able to cope with the perceived threat; and the behavioral and physiological changes that can occur as a result of stress. He also listed stress-related endpoints for use in future health surveillance efforts.

In conclusion, Lawrence Palinkas described in detail what he and other researchers learned about the psychological impact of the Exxon Valdez spill. Based on these results, Palinkas identified populations in the Gulf region that he suspects may be especially vulnerable to psychological stress (e.g., previously traumatized populations) and recommended certain types of data to include in surveillance.

Assessing the Early Mental Health Effects of the Gulf Oil Spill

Howard J. Osofsky, Louisiana State University Health Sciences Center


Disasters increase the prevalence of adverse mental health outcomes, but research focused on these outcomes and application of knowledge generated by such research is somewhat limited, especially where it concerns the well-being of children and families, said Howard Osofsky. Assessment can be difficult because of the interactions between psychological, physical, and neuropsychiatric health. Moreover, developmental considerations are of particular importance given that Louisiana’s state-level crisis and response program (Louisiana Spirit) is already receiving

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

from schools calls related to the potential for learning-cognitive difficulties, impulse-control issues, and risk-taking behavior as a result of the oil spill disaster.

While there are studies of natural and technological disasters that have investigated early mental health effects related to substantial changes in way of life, employment, and income, the Gulf oil disaster is unique for several reasons:

  • Retraumatization: The Gulf oil disaster follows closely on the heels of Hurricanes Katrina, Rita, and Gustav and an economic recession. For individuals that survived the hurricane traumas, the cumulative effects of multiple traumas may increase susceptibility to psychological conditions or disorders.

  • Population diversity: The Gulf community is large and ethnographically and culturally diverse, even within the affected parishes. Particular aversions to participation, such as “avoidance” or a desire not to talk about problems, is an expected part of the culture in affected communities.

  • History: Other unique aspects of the Gulf region’s history may affect surveillance and monitoring activities. For instance, multiple generations of fishermen and -women may lose their livelihoods. Gulf residents also exhibit an ambivalent relationship with the oil companies, leading residents to be suspicious of safeguards, even while the residents depend on oil companies for their livelihoods.

Retraumatization may increase the risk of developing adverse psychological-health effects. Following Hurricane Katrina, Osofsky and his colleagues collected 5 years of pre-oil spill data on children, adolescents, and some first responders. These data will continue to be collected, and researchers will continue to measure the cumulative effects of multiple traumas. (A summary of Osofsky’s presentation in Chapter 6 provides additional information about these studies.) These data can provide a baseline from which to assess the cumulative effects of multiple traumas, to track trends, and to predict the need for health care services. For instance, 40 percent of the first responders surveyed after Katrina requested help for themselves or their families.

A number of data-collection activities are currently under way. Osofsky stated that he was already receiving reports from domestic-violence shelters and drug courts. Focus groups have revealed increases

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

in suspiciousness, arguing, domestic violence, depressive symptoms, suicidal thoughts, consumption of alcohol, acute anxiety, and fear. On the other hand, some people have expressed relief that family members are not employed as responders in relief efforts because it means less exposure to toxins. Osofsky ultimately predicted that mental health problems would likely become much worse over time as a result of the Gulf oil spill.

Finally, Osofsky described the importance of establishing a long-term working relationship with local communities and organizations. Osofsky explained that individuals in the affected communities do not want handouts, but do want “hand-ups”—meaning that those individuals want information and assistance to help guide their approaches in the future. In addition to earning the trust of local community members, working with communities can also provide information about how best to link people with available services or about the need for additional resources.

Long-Term Psychological Stress and Disease: Implications for the Gulf Oil Spill

Sheldon Cohen, Carnegie Mellon University


Drawing on scientific literature that addresses a wide range of stressful events that have been associated with adverse health effects (such as job loss and personal stressors such as divorce), Sheldon Cohen explained how the existing literature on the connection between psychological stress and disease can provide information about the long-term effects that could be expected as a result of the Gulf oil spill. Many of the stressful events that have been associated with disease risk are fundamentally similar to events that currently affect people in the Gulf region. For example, individuals are reporting lower self-esteem, sometimes resulting from job loss; loss of purpose or meaning in life, such as a loss of career aspirations or family businesses; and loss of feelings of control over important outcomes, resulting from the inability to support a family or protect the environment. Other common psychological symptoms associated with poorer health include perceptions of unfair treatment, stemming from causes such as problems with reimbursement for loss, and damage to social networks, often resulting from conflict or loss of close friends.

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
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Cohen further explained that the stress associated with any given event, such as job loss, could be very different for different individuals, depending on how those individuals perceive the event. For example, the perceived stress for someone who is about to retire would be very different than the perceived stress for someone who needs a job to support his or her family. Additionally, the stress of a threatening event could be very different for different people, depending on available coping mechanisms. For example, someone who has supportive friends and family or access to another source of income would experience a different level of stress in response to a threatening event than someone without a support system or alternate source of income.

Psychological stress is known to be associated with many mental health outcomes in adults, including depression, post-traumatic stress disorder, and anxiety disorder, said Cohen. Stress has also been associated with emotional and social conflicts in children. These negative emotional responses can lead to intermittent physiological and other health effects, such as activation of the sympathetic nervous system. Moreover, individuals who have negative emotional responses tend to adhere poorly to medical regimens and to have poor health practices, such as poor sleep quality, poor diets, lack of physical activity, and increased alcohol and drug use. Together, these physiological changes and poor health practices can lead to an increased risk of physical disease.

Cohen stated that psychological stress is also known to be associated with several physical health outcomes in both adults and children, including total mortality and increased risks of coronary heart disease, hypertension, and upper respiratory infections. Stress is also known to exacerbate several chronic diseases, including HIV/AIDS progression, oral and genital herpes, rheumatoid arthritis, and asthma. Indeed, studies demonstrated an increased risk for coronary heart disease (including myocardial infarction, cardiac arrhythmia, and sudden death) within 30 days after the World Trade Center attack and within 60 days of SCUD-missile attacks in Israel. But not all such risks manifest immediately. Risk for coronary heart disease has also been shown to increase 6 months to several years after work-related stressful events when those events involve a perceived lack of control over work or a perceived lack of institutional fairness.

Populations most vulnerable to stress-associated risk include children, individuals with chronic illnesses, histories of poor coping, a lack of close social ties, and lower levels of income and education (because they have fewer resources to help them cope with stressful events).

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

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,

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
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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.

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).

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
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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

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
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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.

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
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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

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

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.

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

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.”

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
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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.

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
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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

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

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

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×

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.

Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
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Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
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Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
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Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
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Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
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Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
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Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
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Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 50
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
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Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 52
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 53
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 54
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 55
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 56
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 57
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 58
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 59
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 60
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 61
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 62
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 63
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 64
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 65
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 66
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 67
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 68
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 69
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 70
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 71
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 72
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 73
Suggested Citation:"3 Short- and Long-Term Effects on Human Health ." Institute of Medicine. 2010. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health: A Summary of the June 2010 Workshop. Washington, DC: The National Academies Press. doi: 10.17226/12949.
×
Page 74
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From the origin of the leak, to the amount of oil released into the environment, to the spill's duration, the 2010 Gulf of Mexico oil spill poses unique challenges to human health. The risks associated with extensive, prolonged use of dispersants, with oil fumes, and with particulate matter from controlled burns are also uncertain. There have been concerns about the extent to which hazards, such as physical and chemical exposures and social and economic disruptions, will impact the overall health of people who live and work near the area of the oil spill.

Although studies of previous oil spills provide some basis for identifying and mitigating the human health effects of these exposures, the existing data are insufficient to fully understand and predict the overall impact of hazards from the Deepwater Horizon oil spill on the health of workers, volunteers, residents, visitors, and special populations. Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health identifies populations at increased risks for adverse health effects and explores effective communication strategies to convey health information to these at-risk populations. The book also discusses the need for appropriate surveillance systems to monitor the spill's potential short- and long-term health effects on affected communities and individuals.

Assessing the Effects of the Gulf of Mexico Oil Spill on Human Health is a useful resource that can help policy makers, public health officials, academics, community advocates, scientists, and members of the public collaborate to create a monitoring and surveillance system that results in "actionable" information and that identifies emerging health risks in specific populations.

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