April 19, 2001
Chapter for On Line Textbook
Children’s Health and Public Policy
Children today face an array of exposures to potentially toxic environmental hazards. Hazardous substances such as lead, PCBs, solvents, asbestos, radon, pesticides, and air pollution have found their way into the homes, schools, and playgrounds of children. These exposures can have a significant impact on children's health and well-being: all children are at risk of developing learning disabilities, chronic and acute respiratory diseases, cancers, and illnesses caused by damage to the nervous system from hazardous substances.
Children today live in an environment that is vastly different from that of previous generations. Explosions in technology, information, population and material goods mark the end of the 20th century. One of the key contributions to the current technological age has been the discovery and the use of thousands of new chemicals. During the last 50 years hundreds of thousands of chemicals have been developed and the production of synthetic chemicals has increased from 1.3 billion lbs in 1940 to 320 billion lbs in 1980.1 Chemicals are ubiquitous in our environment worldwide, and traces of man-made chemical compounds (toxicants) are found in all humans and animals.2 Currently, use of more than 70,000 chemicals is allowed in the United States and little is known about the health effects of majority of these chemicals on children.3 Exposures to environmental toxins, such as lead, are now known to cause permanent damage to a child’s nervous system. 5 Other toxicants are being implicated in causing adverse health effects in children. 6,7 While exposures to some environmental hazards have decreased because of new regulations and standards, children continue to be exposed to toxicants in the air, water and food. 8
Why Children are Considered Special Population:
A knowledge of the normal growth and development of children is essential for preventing and detecting disease by recognizing overt deviations from normal patterns. Although the processes of growth and development are not completely separable, it is convenient to refer to “growth” as the increase in the size of the body as a whole, or the increase in separate parts, and to reserve “development” for changes in function which includes those influenced by the emotional and social environment. 4 Children form a unique subgroup within the population who require special consideration in risk assessment. Children are not little adults. Their tissues and organs grow rapidly, developing and differentiating. These development processes create windows of great vulnerability to environmental toxicants. 9 One goal of pediatrics is to help each child achieve his or her individual potential for growth and development, thus becoming a mature adult. 4 The development of a human being from conception through adolescence affords particular windows of vulnerability to environmental hazards. Exposure at those moments of vulnerability can lead to permanent and irreversible damage. An important means of accomplishing this goal involves periodically monitoring each child for the normal growth and progression of growth and development and screening for abnormalities.4 Infancy is considered to be from 0 – 12 months, early childhood is from 15 months – 4 years, late childhood is from 5 years – 12 years and adolescence from 14 years – 20 years. 4 Exposure patterns of children to environmental chemicals are very different from those of adults. Traditional risk assessment has generally failed to consider the special exposures and the unique susceptibilities of infants and children. 9
Children, beginning at the fetal stage and continuing through adolescence, are physiologically very different from adults. They are in dynamic state of growth, with cells multiplying and organ systems developing at a rapid rate. At birth their nervous, respiratory, reproductive and immune systems are not fully developed. In the first four months of life an infant more than doubles its weight. Young children breathe more rapidly and take in more air in proportion to their body weight than do adults. They also have higher metabolic rates and a higher proportionate intake of food and liquid than do adults. 10
The rate at which children absorb nutrients from the gastrointestinal tract is likewise different than the rate for adults, a fact that can impact their exposure to toxicants. For example, children have a greater need for calcium for bone development than do adults and will absorb more of this element when it is present in the gastrointestinal tract. When lead has been ingested into the gut, however, the body will absorb it in place of calcium. Consequently, an adult will absorb 10% of ingested lead, while a toddler will absorb 50% of ingested lead. 11
Because metabolic systems are still developing in the fetus and child their ability to detoxify and excrete toxins differs from that of adults. This difference is sometimes to the child’s advantage, but more frequently they are not able to excrete toxins as well as adults, and thus more vulnerable to them.12 Not only does a child’s physiology differ from an adult’s, so does its environment. In its first environment, its mother’s womb, the fetus may be permanently damaged by exposure to a wide variety of chemicals that can cross into the blood stream through the placenta. These chemicals include lead, 13 polychlorinated biphenyls, 14 methylmercury15 ethanol and nicotine from environmental tobacco smoke. 11
Behavior characteristic of early childhood also affect a child exposure to toxicants. In the first year of life the young child spends hours close to the ground where he or she may be exposed to toxicants in dust, soil and carpets as well as to pesticide vapors in low-lying layers of air.
Normal development in early childhood includes a great deal of hand-to-mouth behavior, providing another avenue for exposure to such toxicants as lead in paint dust or chips and to pesticide residues.
Children spend more time outdoors than do most adults, often engaged in vigorous play. Because children breathe more air per pound body weight than adults and because their respiratory systems are still developing, they are prone to greater exposure to and potential adverse effects from air particulates, ozone and other chemicals that pollute outdoor air. 16, 17
Finally, a child’s diet differs in important ways from that of an adult. Children eat more fruits and vegetables and drink more liquids in proportion to their body weight, their potential exposure to ingested toxicants such as lead, pesticides, and nitrates is greater. For example, the average infant’s daily consumption of six ounces of formula or breast milk per kilogram of body weight is equivalent to an adult male drinking 50 eight-ounce glasses of milk a day. 11 Likewise, proportionate to its body weight, the average one-year-old eats two to seven times more grapes, bananas, pears, carrots and broccoli than an adult. 18
The fact that children are exposed to toxicants at an earlier age than adults, they have more time to develop environmentally-triggered diseases such as cancer and possibly Parkinson’s disease. 19
All children are affected by environmental hazards. Pollution and environmental degradation know no county, state, regional, or national border. Contaminants are transported through many media including air, water, soil and food throughout the world. However, children living in poverty and children in racial or ethnic communities are at disproportionate risk for exposures to environmental hazards. Poverty can compound the adverse effects of exposure to toxicants because it is so often associated with inadequate housing, poor nutrition, and limited access to health care. A primary source of exposure to lead, for example, is from flaking lead-based paint, a condition that is more common in poorly-maintained older housing often found in low-income neighborhoods.
Higher rates of poverty are one of the factors that place children of ethnic and minority communities at disproportionate risk for environmental exposures.
Communities of color are disproportionately exposed to hazardous wastes, dioxin, and air pollution. Existing data demonstrate that children of color are the subgroup of the population most exposed to certain pollutants, including lead, air pollution, and pesticides.
The health status of children belonging to low-income and racial ethnic communities reflects their increased risk of exposure to environmental hazards. Eight percent of low-income children are lead poisoned compared to 1.9% of middle- and 1.0% of high-income children. African-American and Mexican-American children have higher rates of lead poisoning than white non-Hispanic children (11.2% and 4.0% respectively compared to 2.15). 21 Rates for asthma-related deaths and hospitalizations are routinely higher for African-American children than for Caucasian children. Coupling the risk factors of poverty with environmental exposures places children in racial and ethnic communities at multi-factorial risk for illness.
Children face myriad environmental hazards: including radiation, solvents, asbestos, mercury, arsenic, sulfur dioxide and ozone. They fall into categories such as neurotoxins, endocrine disruptors, carcinogens, and respiratory irritants and inflammatants. Selected environmental hazards known to seriously impact children’s health are discussed below.
Lead poison has been referred to as the most important environmental health hazards for children. Exposure to lead has been associated with an array of neuro-developmental effects, including attention deficits, decreased IQ scores, hyperactivity and juvenile delinquency. 21,22 Research has also shown an association between slightly elevated blood lead levels in children at the age of 24 months and lower general cognitive function at age 5 years of age. 23
The elimination of gasoline in the 1970s, one of the great public health success stories of that decade, resulted in significant decreases in blood lead levels. 24 Although lead has been removed from most paint products now in the market, lead-based paint in older homes is still the most common source of high-dose lead exposure for preschool-aged children. Nationwide, approximately 3 million tons of lead remain in an estimated 57 million occupied private housing units built before 1980, a figure that represents 74% of the nation’s housing stock. 25 Childhood lead exposures can occur through ingestion of paint chips or dust from deteriorating surfaces, from chewing on painted cribs or through inhalation of lead paint dust produced by sanding during renovation. 24 Lead is also found in drinking water as a result of leaching from lead-soldered plumbing and in soil containing lead residues form automobile exhaust. 6
Air pollution affects children more than adults because of their narrow airways, more rapid rate of respiration, and the fact that they inhale more pollutants per pound of body weight. 27 Common indoor air pollutants include carbon monoxide, radon environmental tobacco smoke, asbestos, formaldehyde and mercury. Common outdoor air pollutants include ozone and particulate matter.
Health effects associated with both indoor and outdoor air pollution include increased perinatal mortality, increased acute respiratory illnesses (e.g. bronchitis and pneumonia), aggravation of asthma, increased frequency of physician visits for chronic cough and ear infections, and decreases in lung function. 17 During the last 25 years, several hundred papers have been published on respiratory health effects of environmental tobacco smoke (ETS). Various independent assessments have concluded that ETS causes lung cancer in adult non-smokers and increases the risk of various non-cancer effects, principally in children. The effects on children include pneumonia, bronchitis and bronchiolitis in young children: chronic middle ear effusion: increased frequency and severity of attacks among asthmatics; possible induction of asthma in previously asymptomatic individuals; small reductions in lung function; and symptoms of upper respiratory tract infection. 20 A recent study of neonatal mortality found an association between elevated concentrations of fine particulates and neonatal deaths, including sudden infant death syndrome (SIDS). 28 There is little doubt that high levels of air pollution are responsible for increased morbidity, and in some cases mortality in children. 17
Increased indoor air pollution can be attributed to what are generally considered to be improvements in our quality of life. These include energy saving measures such as better insulation and decreased ventilation rates in houses, increased furnishings, increased mean indoor temperature and increased indoor humidity. 29 In addition, the number of airtight buildings has increased since the 1970s, as has the use of synthetic building materials and unvented combustion appliances. 30 These factors coupled with an increase in the amount of time we spend indoors have increased the concentration of indoor environmental pollutants and our exposure to them.
In the outdoor environment, there has been as effort to reduce exposure to ozone and particulates. Ozone, the most pervasive air pollutant in the United States, is produced when hydrocarbons and nitrogen oxides emitted from motor vehicles and other sources react in the presence of sunlight. 31 Exposure to ozone has been associated with increased asthma rates in children32 as well as a reduction in lung function, and also causes exercise-related wheezing, coughing and chest tightness. 31 Most recently the US Environmental Protection Agency has issued regulations to decrease the levels of ozone and air particulates in outdoor air.
Children are often exposed to toxicants through the agricultural and home use of pesticides or the ingestion of pesticide residues on food or in water. Pesticides used today generally fit into five main categories: insecticides, herbicides, fungicides, nematocides and rodenticides. 33 Increased awareness of acute pesticide poisoning has led to an apparent decrease in acute episodes of toxicity, and public health concern has thus shifted to evaluating the effects of low level chronic pesticide exposures. 33 Again, children may be more vulnerable than adults to experiencing latent or delayed effects over the long course of their lifetime. Researchers have become concerned about the potential associations between chronic pesticide exposures and chemical carcinogenesis, environmental estrogen disruption and developmental neurotoxicity.
There has been an increase in some childhood diseases over the years. As noted, childhood asthma has increased by more than 40% since 1980, affecting more than 4.2 million children under the age of 18 in the U.S. The incidence of two types of childhood cancers has risen significantly over the past 15 years: acute lymphocytic leukemia is up 10% and brain tumors are up more than 30%.32 There are various environmental causes of cancer in children. Etiologically, these are divided into physical agents, chemical agents, and microbiologic agents. 4 The physical agents include ionizing radiation causing leukemia, thyroid and breast cancer, and ultraviolet radiation causing melanoma, basal and squamous cell cancer in xeroderma pigmentosum. Chemical agents include cigarette/tobacco causing lung, oropharynx and laryngeal cancer, diethylstibestrol – vaginal carcinoma, asbestos – mesothelioma, androgens, aflatoxin, vinyl chloride – hepatic cancer, alkylating agents, benzene – leukemia, immunosuppressant drugs, phenytoin – lymphoma, and cyclophosphamide causing bladder cancer. 4 Microbiological agents include Hepatitis B, C viruses causing hepatic cancer, HIV – Kaposi Sarcoma, lymphoma, Schistosoma hematobium – bladder cancer, Epstein-Barr virus – African Burkitts lymphoma, Papillomavirus – cervical cancer, Human T lymphotropic virus 1 – T-cell lymphoma, and SV40 virus causing ependymoma, choroid plexus tumor. 4
The key to protection is prevention. Recently there has been a dramatic shift in the recognition of children’s environmental health issues in the Congress and federal agencies. Identification of environmental hazards as it affects children dated back in 1774 where there was increase in scrotal cancer among young chimney sweeps. Lead was discovered (in Australia, 1904) and then mercury, causing neurological damage to the unborn child (in Sweden, 1953, in Japan, 1958, 1965, in Iraq, 1971 and New Mexico in 1972). In 1970, the Clean Air Act was adopted by President Nixon. 31 In the 1970s, the EPA tackles lead in gasoline. In 1989, pesticides were labeled “intolerable risk” in children’s food. Alar was removed for use on apples. 31 In November 1996, the U.S. Environmental Protection Agency (EPA) released a report Environmental Health Threats to Children and announced that for the first time children would be considered in all EPA risk assessment and standard-setting procedures. Adoption of a new child-centered agenda for research and risk assessment is necessary if disease in children of toxic environmental origin is to be identified, understood, controlled, and prevented. 9 Congress passed the Food Quality Protection Act in 1996, which specifically focuses on setting standards to protect children from pesticide residues and other hazards in foods. In April 1997, President Clinton signed an Executive Order on Children’s Environmental Health and Safety (#13045) requiring federal agencies to include children and their unique susceptibilities in standard-setting procedures and establishing an interagency task force to ensure coordination of regulations and research. 9 These actions provide an important framework for protecting children. Whether they prove effective will depend on how diligently they are implemented. Over the years, there has been training of Pediatricians to include children’s environmental health. A lot of conferences, symposia and seminars have taken place to increase public awareness. Research has had its place and a lot of research, prevention and the policies focuses on key research priority areas in the field of children's environmental health and these include asthma and respiratory diseases; childhood cancer; endocrine disorders and neurodevelopmental effects. In a bid to provide better protection for children’s health, U.S. Senators (Barbara Boxer and Frank Lautenberg) introduced the Children’s Environmental Protection Act (CEPA) on 24 May 1999. CEPA is an amendment to the Toxic Substances Control Act of 1976 and seeks to protect children from exposures to hazardous substances such as air pollutants and pesticides sprayed in schools. The Act provides parents about how to protect their children against such health threats. 39 There is on-going research being done and legislation being worked on to further advocate for children’s health and make the world a better place to live in.
- Choose to use fewer chemicals, in your home, on your lawn.
- Don't use pesticides if you don't have to - look for alternatives.
- Have your child's blood lead level tested, especially if your child spends time in a house built before 1960.
- Don't smoke or let others smoke near your kids.
- Kids and pregnant women should obey area fish advisories.
- Vary children's diets as much as possible while giving them plenty of fruits and vegetables. Consider buying organic foods if available.
- Pay attention to air pollution reports and limit children's outdoor activities on ozone alert days and other times when air pollution is bad.
- Learn about your local drinking water. Read your water system's Consumer Confidence Report, available from your water supplier.
- Ask your pediatric health care provider to take an environmental health history of your child.
- Work with your school, community recreation system and others to decrease their use of chemicals. Many schools are cutting back on pesticide use and are giving parents advance notice before applying pesticides.
- Tell your elected officials that you want government policies to specifically take children into account that protect children's health.
With children being so susceptible to many hazards of life especially environmental, one has to be sensitive to the continuous environmental changes. One should educate oneself and understand more about children’s health and talk to other people about the problems children face. Health education should not be limited to professionals but also to the at-risk group. Ways of communication should be devised to those who cannot read. Letters can be written to senators, representatives, congress and other government officials to work together to put a policy in place to improve children’s health. An effective policy is reliant upon knowledge and understanding of the effects of environmental hazards on children’s health. Research also has to be geared towards identifying patterns of environmental diseases, assessing children’s exposures to environmental toxicants so as to determine developmental periods of vulnerability. Quantification of dose response relationships will also lead to preventive measures.
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