41 Environmental Health Issues

“All things are connected. Whatever befalls the earth befalls the children of the earth.”

The environment is a basic determinant of human health and illness. It is estimated that 13% to 37% of the global burden of disease can be attributed to three major categories of environmental risk factors: water, sanitation, and hygiene; indoor air quality; and outdoor air quality (Prüss-Üstün et al, 2008). Children between birth and 14 years old bear nearly half the burden of disease in low- and middle-income countries (World Health Organization [WHO], 2008). Environmental factors are estimated to contribute to 100% of lead poisoning, 30% of asthma, 5% of cancers, and about 10% of neurobehavioral disorders. In a classic study based on these estimates, the annual cost of environment-related illness in children in the U.S. in 2002 was calculated to be $54.9 billion (Landrigan et al, 2002). Since then, individual states have estimated costs that are at least as high or higher.

Chemicals, natural as well as synthetic, constitute a large part of the environmental risk to health, contaminating water, soil, and air. Naturally-occurring elements like radon cause lung cancer. There is sufficient scientific evidence of a causal link between prenatal or childhood exposure to methyl mercury, polychlorinated biphenyls, polychlorinated dibenzofurans, active maternal smoking (during pregnancy), environmental tobacco smoke (ETS) (during childhood), and 2,3,7,8-tetrachlorodibenzo-p-dioxin and adverse health outcomes in children and adults (Wigle et al, 2008). Research indicates that chemical exposure of the father or mother prior to conception, at the time of conception, and (for the mother and fetus) during pregnancy results in a gene-environment interaction that accounts for most adverse developmental outcomes of pregnancy (Mattison, 2010). Concern has been raised that human exposure to genetically modified organisms (GMOs) and to hormones fed to animals may contribute to cancers, hepatorenal toxicity, and long-term reproductive problems (de Vendômois et al, 2009). In 2009 the U.S. Department of Health and Human Services (USDHHS) and the Centers for Disease Control and Prevention (CDC) released the Fourth National Report on Human Exposures to Environmental Chemicals, showing that almost all subjects studied had measurable levels of many industrial toxins in their blood and urine (USDHHS and CDC, 2009). Yet despite the known effects of many environmental agents and despite the presence of toxins in almost all humans, a great deal of uncertainty about the relationship between the environment and disease and illness remains. Many providers are at a loss when confronted with questions about environmental health, do not know how to best approach it, or feel overwhelmed by the volume and complexity of environmental health information. The challenge lies in several areas:

• Some providers may believe the effect of environmental agents is negligible, that lifestyle choices, genetic conditions, and/or infectious agents are responsible for most disease.

• There is not always definitive evidence that exposure to an environmental agent causes a particular disease. Is the condition being seen clinically caused by environmental exposure or something else?

• Exposure to some environmental agents may cause disease if there are preexisting or genetic conditions, or agents working together may cause problems (e.g., tobacco smoke and radon combined). It is often difficult for the provider to sort out the many variables.

• Research findings vary as to the type of problem caused by an environmental agent. What effect does an environmental agent have on the human body? Using the Multiple Exposure-Multiple Effects model (Briggs, 2003), some agents can cause several problems, and many different agents may cause the same problem (e.g., cancer). Sometimes the effect may be so subtle as to be missed: a decline in IQ scores after exposure to lead may still leave the child within the range of “normal” IQ.

• To what environmental agents has this individual been exposed? When? The health effect of an agent may be delayed for years and the exposure forgotten or unnoticed at the time it occurred (e.g., asbestosis, melanoma).

• Some providers may believe that correcting environmental health problems is beyond their purview. Exposure to disease-causing agents, they think, is a systemic not an individual issue, so beyond treating the illness, they may feel they can do nothing to help their patients or change the system.

• Providers feel inadequate to the task; they are not prepared well to manage environmental health concerns. Many providers state they lack knowledge and confidence in managing children’s environmental health issues, failing, for example, to know about and use available resources (e.g., the Pediatric Environmental Health Specialty Unit [PEHSU] in their region) (Trasande et al, 2010). Nursing and medical schools do not devote sufficient time to teaching about environmental health, and continuing education may be limited.

To complicate matters, this uncertainty on the part of providers and in the field of pediatric environmental health is taking place in a social and economic context where profit, not concern for health, drives corporate development. Companies that produce chemicals or GMOs often conduct their own safety testing, and the results may not need to be made public. Approximately 83,000 chemicals are registered for use in the U.S.; however, less than half of these have any laboratory testing at all. Almost 3000 of these chemicals are produced in quantities of 120 tons or more annually and 80% of these have no information available about developmental or pediatric toxicity. Further, the information available almost never considers interactions among chemicals or genetic susceptibility (Grandjean and Landrigan, 2006). Though corporations state they do not intend to cause health problems with their products, examples of environmental contamination, advertising to vulnerable groups (e.g., cigarettes to adolescents), cover-ups of harmful findings (e.g., tobacco company assertion that nicotine is not a health risk), and regulatory violations occur frequently (Shrader-Frechette, 2007).

Regulation of chemical toxins is difficult. The Toxic Substances Control Act (TSCA) of 1976 authorizes the U.S. Environmental Protection Agency (EPA) to require testing and reporting of some chemicals and to restrict mixing of some toxic substances. However, the requirements of regulation are high: the EPA must demonstrate that the chemical in question represents an “unreasonable risk” to human health in order to ban its use. Also, many chemicals used in cosmetics, foods, drugs, and pesticides are exempt from the law (Duderstadt, 2009).

Because it is difficult to establish direct cause and effect in the area of environmental health, it would be prudent to adopt a precautionary approach to environmental toxins. Many European nations operate using the precautionary principle, which stipulates that chemicals should not be introduced into the environment until they have been proven to be safe. In the U.S., unfortunately, a “cost-benefit” approach is used, in which the burden of proof falls on regulatory agencies (e.g., the EPA) to show that the chemical represents an “unreasonable risk” to health. The cost of testing and regulating chemicals to ensure they are safe is balanced against the health problems those chemicals might cause, and, to date, U.S. industry has successfully been able to argue that it can be “too costly” to control pollution and restrict exposure for many chemicals (Schapiro, 2007). As a result, many people are unnecessarily exposed. Health care providers across the U.S. must advocate for use of the precautionary principle to control exposure to environmental toxins nationally and internationally.

The current situation is grim, but it is important to note that health care providers are increasingly aware of the problem, and many efforts are being made to address environmental health in pediatric practices. A network of regional PEHSUs has been created to provide information, clinical consultation, and support for pediatric providers (see www.aoec.org/PEHSU.htm). In 1999, the American Academy of Pediatrics (AAP) published a pediatric environmental health manual for providers (Etzel and Balk, 2003). Educators are developing curricula and preparing materials for students in health disciplines (Beitz and de Castro, 2010; Jamil et al, 2010); some are suggesting a medical specialty in environmental medicine (le Moal and Reis, 2011), and tools for assessment and management of environmental variables continue to be written (Cohen Hubal et al, 2010; Judson et al, 2008; Kavlock and Dix, 2010). New technology allows for more sophisticated assessment of how chemicals affect the human body, and intricacies of the environment-health relationship are better understood. Lack of strong evidence for a cause-effect relationship is not due to absence of an effect; rather, more research is needed to clearly establish the connections (Wigle et al, 2008). In 2000, the U.S. Congress authorized the National Children’s Study to investigate the root causes of many childhood and adult diseases. It is proposed that 100,000 children be followed from before conception until 21 years old, examining environmental influences on health, including diet, ambient air, and home and school environments as well as interactions with various genetic traits. As of 2010, 37 regional participation sites had been identified; the challenge is to develop a recruitment plan, assessment tools, and protocols to coordinate, administer, and conduct the research (Savitz and Ness, 2010).

Health care providers need to be able to give their clients the most accurate information available about environmental health issues. Parents may suspect that an illness is associated with environmental conditions, or express concern about the risk of exposure to untested substances. The provider who is knowledgeable about the potential hazards of environmental exposure will be able to explain the possible connections, collect clear assessment data, and work closely with families to make appropriate treatment choices, including referral and consultation with public health authorities. If not personally knowledgeable, the provider should know where to get information. A core competency for all nurse practitioners (NPs) states that the NP “recognizes environmental health problems affecting patients and provides health protection interventions that promote healthy environments for individuals, families, and communities” (USDHHS, 2002). This chapter is designed to help prepare providers to meet this competency. In addition to direct patient care and education, primary health care providers can collaborate with other health care providers, conduct research to identify environmental problems, and advocate in the public arena (e.g., industry, policy, funding, and regulation) for more responsible management of environmental agents that affect health.

Principles for Understanding Children’s Environmental Health

Children’s Increased Risk for Environment-Related Illness

Children, because of their developmental immaturity, rapid growth, size, and behavior, are particularly susceptible to environmental threats (Table 41-1). Exposure to toxins or other harmful substances affects growth and damages organs or body systems during critical developmental periods or windows of vulnerability, prenatally and during childhood. It is known, for instance, that a 50-mg dose of thalidomide, administered during the 26^th day of gestation will likely result in major malformations to an embryo but that same dose taken at the 10^th week of gestation will have no effects (Brent, 2004). Toxicants that cross the placenta (e.g., drugs, carbon monoxide [CO], mercury, lead, and cotinine [from environmental tobacco smoke]) can contribute to low birthweight, spontaneous abortion, intrauterine growth retardation, increased risk of cancer, poor cognitive and behavioral development, and birth defects. Approximately 3% of all babies born in the U.S. have a serious birth defect. The rate of some birth defects is increasing (Brent, 2004), and about 10% appear to be related to environmental exposure (Chervenak et al, 2010).

TABLE 41-1 Environmental Risk Factors for Children at Different Stages of Development

Children’s rapidly growing tissues more readily absorb environmental toxins; the lungs, skin, and gastrointestinal (GI) tract of newborns are highly permeable and gastric pH is high, facilitating absorption. At the same time, newborns’ immature organ systems more slowly metabolize drugs, making it more difficult for infants to detoxify and excrete harmful substances. Children consume more fresh fruit, water, milk, and juice per pound of body weight than adults; many of these products are treated with pesticides or other chemicals. Children engage in more outdoor activities than adults, breathe more pollutants per pound of body weight, and are physically closer to many potentially harmful substances. Crawling on floors, chewing on objects, and running and rolling in grass are behaviors that expose children to environmental toxins and can result in lead poisoning, pesticide poisoning, and respiratory problems, including asthma. Adolescents are particularly susceptible to environmental tobacco smoke and occupational hazards. Children living in poorer communities are at higher risk than others. Poor housing and nutrition, high levels of lead, toxic waste deposits, and limited access to health screening and treatment contribute to increased risk.

In addition to the immediate risk during childhood, children have a longer time span for exposure to environmental toxins, and with some conditions children are more likely to suffer health problems than adults exposed to the same substance.

Understanding Environmental Health Hazards

As noted, a direct cause-effect relationship between health and the environment may be impossible to determine because (1) the extent of exposure may be unclear; (2) there can be a long latency period between exposure and appearance of illness; (3) an individual may have exposure to multiple confounding agents; (4) exposure may need to occur during a “window of vulnerability” (e.g., during the period when a particular body system is forming prenatally) for the agent to have an effect; (5) some individuals may have a genetic susceptibility to an exposure, whereas others do not; and (6) much research in environmental health has been short term, or conducted on animals, so results may not translate to human development. Using principles of epidemiologic relationships and toxicology, however, providers can better understand and explain to their patients the relationship between environment and health.

Epidemiologic Model: Risk Assessment Approach

A first step in an epidemiologic approach (Fig. 41-1) identifies the interactive factors in the environment, including receptors (i.e., hosts or living things that are susceptible or exposed to environmental agents); toxins, or harmful substances that might cause damage (i.e., the agent); and the environmental medium, or route by which exposure could occur (e.g., air, water, or food).

FIGURE 41-1 Risk assessment of environmental hazards.

(Adapted from Oregon Poison Center and Health Division, Oregon Department of Human Resources: Environmental hazards in perspective: seminar syllabus and environmental health resource notebook, Portland, 1994, Oregon Department of Human Resources.)

A second step of risk assessment using an epidemiologic model is to determine the possibility that harm could occur. A number of questions are asked when making this determination:

• How susceptible is the receptor to the agent (e.g., age, sex, genetics, diet, and general health)?

• At what quantity (i.e., dose) will the agent present a problem or cause a response in this receptor? This amount is called the applied action or dose-response level. For some agents, any exposure represents a risk.

• What is the concentration of the toxic agent? How much is there? How strong is it? How long will it stay around? What is the extent of contact of the toxic agent with the receptor?

A final step in this process compares the actual environmental condition with the applied action level, asking the following question: With the amount of exposure present, is the individual at risk for health problems?

Toxicologic Principles

Toxicologic principles are those the primary care provider has learned related to pharmacologic therapy: exposure, absorption, distribution, metabolism, tissue sensitivity, and effects—therapeutic or toxic. In fact, Paracelsus (1493-1541), considered the “father of toxicology,” is reputed to have said, “All substances are poisons; there is none that is not a poison. The right dose differentiates a poison from a remedy.”

Primary Care Approach to Children’s Environmental Health

Assessment

Assessment of environmental health hazards should be integrated into regular health appraisals, as well as examinations of ill children. Figures 41-2, 41-3, and 41-4 list essential questions to ask for an environmental history, including questions related to asthma.

FIGURE 41-2 Pediatric environmental history (0 to 18 years of age): The screening environmental history.

Used with permission of the National Environmental Education Foundation, Washington, DC. Available at www.neefusa.org/pdf/PedEnvHistoryScreening/pdf (accessed Apr 4, 2011).

FIGURE 41-3 Pediatric environmental history (0 to 18 years of age): additional categories and questions to supplement the screening environment history.

(Used with permission of the National Environmental Education Foundation, Washington, DC. Available at www.neefusa.org/pdf/PEHIhistory.pdf. Accessed April 4, 2011.)

FIGURE 41-4 Environmental history form for pediatric asthma patient.

(Used with permission of the National Environmental Education Foundation, Washington, DC. Available at www. neefusa.org/health/asthma/historyform/htm. Accessed December 1, 2011.)

Physical Examination

The physical examination should cover all body systems thoroughly. Evaluate agent-specific findings (e.g., burns caused by chemicals and neurotoxicity caused by mercury), but also look for subtle, nonspecific signs and symptoms (e.g., skin rashes and headaches). The effects of toxicants on the body can be subclinical in many cases, and effects can occur long after exposure.

Diagnostic Studies

Laboratory studies can be performed on patients as indicated, based on signs and symptoms. Agent-specific laboratory studies, if available and reliable, can be helpful in determining treatment plans. However, few tests are appropriate for use in primary care settings because of the following limitations:

• For most toxins, valid and reliable tests have not been developed.

• For those toxins that do have tests, not all laboratories are capable of performing them. The provider should consult with individual laboratories regarding their capabilities.

• Many tests show a wide range of reference levels at which “toxicity” appears.

• There may be little correlation between exposure and levels present in the body at the time the test is done. Levels may have returned to normal, despite damage done to the body; or a one-time sample can reflect recent active exposure, but not measure the total body burden of the contaminant.

Some available tests include the following:

• Plasma lead levels

• Gas-liquid chromatography (for PCBs)

• Atomic absorption spectrometry (for mercury)

• Carboxyhemoglobin (for CO poisoning)

• Twenty-four-hour urine (for heavy metals)

• Urinary cotinine assays (for tobacco metabolites)

• Plasma cholinesterase (ChE) levels (for pesticide metabolites, organophosphates)

Management of Environmental Conditions

Management of illness related to environmental factors uses a public health model of primary, secondary, and tertiary prevention. A multidisciplinary approach that includes epidemiology, pediatrics, toxicology, public health, and health economics is necessary to treat specific conditions, as well as to prevent exposure to toxins. In addition to caring for acute exposures, providers should inform patients and families about health risks and the nature of environmental contaminants, advocate for healthy environments in the creation of public policy, and work with other professionals to report, monitor, and control exposures. The regional PEHSUs and many online sources provide information and support for clinical, toxicologic, educational, and policy work.

Primary Prevention

The goal of primary prevention is to keep a problem from occurring and to maintain a level of wellness. Education of individuals and the public to help them identify health hazards and prevent exposure is a form of primary prevention. Providers can find a wealth of information about specific toxins, patient support groups, advocate activities, and safety practices and regulations on the Internet. Primary prevention also includes assessment of communities and populations. Safety inspections in industry and public areas (e.g., school playgrounds); monitoring of lead or radon in homes, schools, and workplaces; and scientific research to determine connections between environmental agents and disease are examples of early assessment. It is important to conduct research on children, adapt research methodologies to the unique characteristics of children, and develop biologic markers to better assess the effect of environmental hazards on children as the National Children’s Study proposes to do.

Primary prevention also takes place at the public policy level. Regulations or legal restrictions can prevent health problems (e.g., through implementation of air and water quality standards, restaurant and food handling regulations, or bans on the use of hydrofluorocarbons). Various U.S. federal agencies function to regulate development and use of hazardous materials (e.g., the EPA, the U.S. Consumer Product Safety Commission, and the Occupational Safety and Health Administration [OSHA]). In 1997, the U.S. joined seven other countries (the G-8) in creating the 1997 Declaration of the Environment Leaders of the Eight on Children’s Environmental Health, raising the issue of protection of children from environmental threats to an international level (EPA, 1997).

Secondary Prevention

Secondary prevention involves early detection, treatment, and referral for identified diseases. Testing for serum lead levels is one form of early detection. Reporting exposures to county and state public health officials helps prevent further contact by removing the child from the contaminant and implementing abatement procedures. Poisoning due to environmental contaminants is reportable in most states.

Tertiary Prevention

Tertiary prevention seeks to rehabilitate and restore the environment to a healthful state (e.g., asbestos and lead abatement, Superfund and “brownfields” cleanup, restoration of wetlands). Individually, patients can take steps to end exposure to a contaminant (e.g., stop using pesticides in the home and follow directions on pesticide usage exactly) or change other behaviors that exacerbate adverse effects (e.g., radon in combination with tobacco smoke is more harmful). Clinical treatment of the individual exposed and follow-up is essential because effects of environmental agents can be severe and may not appear for months or years.

Prevention and Patient Education

The “unknowns” of the relationship between health and environment can be frustrating for both providers and parents. Even though providers may not know of a connection, it is important to listen to and validate patient concerns; this gives the message that the provider is also concerned and will work with patients to best manage the situation. Blanket reassurances are inappropriate, but clinicians can provide perspective to patients by explaining the process of environmental effects on health and encouraging patients to actively control their environment. Providers should also serve as liaisons and advocates between the family and environmental, community, and specialty health care resources.

Common Environmental Agents and Adverse Effects

This section presents a brief discussion of general pediatric poisoning and some common environmental agents that are particularly hazardous to children.

General Pediatric Poisoning

Description

Poisoning is the process in which a substance that interferes with the body’s normal function is taken in by ingestion, inhalation, absorption, or injection. Medications, plants, and chemicals are common causes of poisoning in children.

Epidemiology

Poisoning is a major cause of pediatric injury. The mouthing behavior of infants and normal curiosity of toddlers and preschoolers put infants and young children at high risk for accidental ingestion of toxic materials. Cultural factors and beliefs about medications and vitamins may influence storage practices. More than 2.4 million poisonings occurred in 2008 in the U.S. and more than 50% are among children 6 years old or less (Bronstein et al, 2009). Almost 60% involved prescription or nonprescription drugs or supplements and 13% were related to cleaning products (Franklin and Rodgers, 2008).

Assessment (Rodgers et al, 2007)

History

The following are assessed:

• Type of substance taken in. Name of product and ingredients from label

• Amount of intake

• Exact time of intake or exposure

• Route or method of intake

• Reaction or signs and symptoms and their progression over time

• Emergency care given

• Child’s health status before poisoning (e.g., any significant chronic illness? Is child taking prescription medication?)

• Contact information including phone and address if the assessment is via phone

Physical Examination

Findings vary greatly depending on the type and amount of poisonous substance, time since exposure, and susceptibility of the child. Consulting with a poison control center can provide the provider with the information needed to proceed with the physical examination. Reactions can be local or systemic. Questions to consider while conducting the physical examination include the following:

• When did exposure occur?

• Which body system or systems does the poison affect?

• What are specific signs of the poison’s effect?

• How quickly does the poison have an effect?

• How susceptible is the child?

• What is the child’s age and weight?

Diagnostic Studies

Analysis of specimens (e.g., emesis) can be helpful in determining the type of poison, if unknown. Serum levels of the poison can be assessed for some toxins to determine appropriate treatment of the hospitalized child. In general, however, toxicology screens are not necessary, and diagnosis is made on the basis of history and in consultation with a poison control or pediatric environmental health center.

Differential Diagnosis

A history of exposure distinguishes poisoning or potential poisoning from acute-onset illness. Because there is not always an obvious episode of exposure, the provider should be suspicious of poisoning in otherwise well children who experience sudden seizures, GI distress, or cardiorespiratory collapse.

Management

Management approaches for ingested poisons vary with the type of poison, amount of exposure, time lapse since exposure, and susceptibility of the child. Initial management focuses on airway, breathing, and circulation (the ABCs). No matter what poison was taken in, vital body functions must be maintained. Consultation with a poison control center is recommended.

If the patient is to be treated at home initially, the provider needs to talk with the parent or caregiver approximately ½, 1, and 3 hours after the ingestion. Changes in the child’s condition will dictate changes in the plan of care. If the child requires hospital care, an ambulance may be necessary and the emergency department personnel informed so that they can be prepared appropriately (Rodgers et al, 2007).

Subsequent management involves counteracting or neutralizing the effects of the poison (administration of antidotes), decreasing the amount of poison in the system (gastric decontamination), and providing life-support measures while the body detoxifies itself. For some poisons (e.g., warfarin), observation alone may be sufficient.

Basic decontamination guidelines for contact contaminants are listed in Box 41-1. Prompt action to remove the toxin from the skin (e.g. insecticide exposure) or from the eye may prevent major absorption. With ingested toxins, most liquid products are absorbed completely within 30 minutes and solids within 1 to 2 hours. Thus timing is critical, and because decontamination procedures also contain risks, one must consider whether the technique chosen is likely to be of sufficient value to merit its use. Activated charcoal, an adsorbent agent, has been demonstrated to have good efficacy for many, but not all, toxins. The toxins adhere to its surface, rather than being absorbed from the GI mucosa. The use of gastric lavage is coming into question more and more because it only removes a small portion of gastric contents. Syrup of ipecac is not recommended for use in poisoning (American Academy of Pediatrics [AAP], 2003; Rodgers et al, 2007). Cathartics are often used with activated charcoal but without good evidence to support use. Whole-bowel irrigation with a polyethylene glycol electrolyte into the stomach to cleanse the entire GI tract has been shown to be somewhat successful for substances that are absorbed slowly, such as iron or sustained-release medications (Rodgers et al, 2007).

BOX 41-1 Basic Decontamination Protocol