Children Are Not Little Adults
Children are affected by environmental contaminants differently from adults. Children typically may be more highly exposed to contaminants and are more vulnerable to their toxic effects.
Children generally eat more food, drink more water, and breathe more air relative to their size than adults do, and consequently they may be exposed to relatively higher amounts of contaminants in these media. Children's normal activities, such as putting their hands in their mouths or playing on the ground, create opportunities for exposures to contaminants that adults do not face. In addition, environmental contaminants may affect children disproportionately because their immune defenses are not fully developed or their growing organs are more easily harmed.<
Children's environmental health is important because children experience:
Children, beginning in the womb and continuing through adolescence, are very different from adults. They are in a 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 yet 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.
Different Absorption Rates
The rate at which children absorb nutrients during digestion is likewise different than the rate for adults, a fact that can affect their exposure to toxicants. For example, children have a greater need for calcium for bone development than adults and will absorb more of this element when they eat it. When lead has been swallowed, however, the body will absorb it in place of calcium. An adult will absorb 10 percent of swallowed lead, while a toddler will absorb 50 percent of swallowed lead.
Because metabolic systems are still developing in the fetus and child, their ability to detoxify and expel toxins differs from that of adults. This difference is sometimes to the child's advantage, but more frequently they are not able to get rid of toxins as well as adults, and thus are more vulnerable to them. Not only does a child's bodily processes 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 its bloodstream through the placenta. These chemicals include lead, polychlorinated biphenyls, methylmercury, ethanol and nicotine from environmental tobacco smoke. Researchers are also looking at possible connections between health problems and a group of chemicals called endocrine disruptors, which mimic the body's hormones and have been shown to cause problems in wildlife.
Behaviors characteristic of early childhood also affect a child's exposure to toxicants. A 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 pesticides in low-lying layers of air.
Normal development in early childhood includes a great deal of putting hands in mouths, providing another avenue for exposure to harmful things like lead in paint dust or chips and pesticide residues.
Children also spend more time outdoors than most adults and are often engaged in vigorous play. Because children breathe more air per pound of 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.
Finally, a child's diet differs in important ways from that of an adult. Because children eat more fruits and vegetables and drink more liquids in proportion to their body weight, their potential exposure to harmful things when swallowed 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. 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.
The Arizona Department of Health Service's Summary of Primary Environmental Health Factors is now available online.
What are air pollutants?
The most common air pollutants are groundlevel ozone, particulate matter, carbon monoxide, lead, sulfur dioxide, and nitrogen dioxide. These pollutants, which are often referred to as criteria pollutants, are regulated by ADEQ.
ADEQ sets air quality standards for each of these pollutants to protect children from adverse health effects. The standards specify how much of each pollutant is allowed in the air. Some of the standards are designed to protect children from adverse health effects that can occur after being exposed for a short time, such as one hour or one day. Other standards are designed to protect people from health effects that can occur after being exposed for a much longer time, such as a year. For example,current standards for carbon monoxide are for periods of one hour and eight hours, while the current standard for nitrogen dioxide is for one year.
Some air pollutants which are hazardous (also known as air toxics) have been associated with a number of adverse health effects. Examples of the 188 hazardous air pollutants listed in the Clean Air Act include benzene, trichloroethylene, mercury, chromium, and dioxins. Ambient concentrations result from emissions by local or regional sources such as chemical manufacturing plants, refineries, waste incinerators, electricity generating plants, dry cleaners, cars, trucks, and buses. For some hazardous air pollutants, ambient concentrations also result from emissions that occurred in past years or from natural sources.
How can air pollutants affect children's health?
Several of these pollutants, including ozone and particulate matter, have been associated with increases in respiratory-related diseases in children, including reduction of lung function, increases in respiratory symptoms, and increased severity or frequency of asthma attacks. Lead damages the central nervous system in children. Higher concentrations of particulate matter increase mortality.
Air pollutants have been associated with a number of adverse health effects, including cancers, asthma and other respiratory ailments, and neurological problems such as learning disabilities and hyperactivity.
How might children be exposed to air pollution?
Children breathe more air per pound of body weight and are more susceptible to air pollution than adults. Many air pollutants, such as those that form urban smog and toxic compounds, remain in the environment for long periods of time and are carried by the winds hundreds of miles from their places of origin. Millions of people live in areas where urban smog, very small particles, and toxic pollutants pose serious health concerns.
How can I reduce my child's exposure to air pollution?
Seasonal daily forecasts for the common Valley air pollutants carbon monoxide, particulate matter and ozone are provided using the Air Quality Index, or AQI, to help people understand the relation between local air quality and their health. The AQI acts like a yardstick, with higher air pollution readings corresponding to higher AQI values and greater health risk. Using the color-coded AQI, people can quickly and easily compare a given day's air pollution and health risk and then adjust their outdoor activities to lessen exposure.
What is Asthma?
Asthma - a chronic health problem for children - is an inflammatory condition of the bronchial airways. This inflammation causes the normal function of the airways to become excessive and over-reactive, thus producing increased mucus, mucosal swelling and muscle contraction.
These changes produce airway obstruction, chest tightness, coughing and wheezing. If severe, this can cause shortness of breath and low blood oxygen.
Each individual with asthma suffers a different level of severity. All children with asthma, however, do enjoy a reversal of symptoms until something triggers the next episode.
What are the symptoms of asthma?
Wheezing, though characteristic of asthma, is not its most common symptom. Coughing is noted with even "hidden" asthma when wheezing may not be apparent to the patient, his or her family or the physician.
Any child who has frequent coughing or respiratory infections (pneumonia or bronchitis) should be evaluated for asthma.
The child who coughs after running or crying may have asthma. Recurrent night cough is common, as asthma is often worse at night.
Infants who have asthma often have a rattly cough, rapid breathing and may have an excessive number of "pneumonias," episodes of bronchitis or "chest colds." Obvious wheezing episodes might not be noted until after 18 to 24 months of age.
Chest tightness and shortness of breath are other symptoms of asthma that may occur alone or in combination with any of the above symptoms. Since these symptoms can occur for reasons other than asthma, other respiratory diseases must always be considered.
In a young child the discomfort of chest tightness may lead to unexplained irritability.
Remember: Any child who has frequent coughing or respiratory infections (pneumonia or bronchitis) should be evaluated for asthma.
What triggers asthma?
Episodes of asthma often are triggered by some condition or stimulus. Common triggers of asthma are: exercise, respiratory infections, allergic reactions to allergens such as pollen, mold, animal dander, feathers, dust, food, and cockroaches, weather (such as exposure to cold air or sudden temperature change), cigarette smoke and emotions such as excitement or stress.
How can I decrease the effects of my child's asthma?
Avoiding trigger factors can make a great difference in your child's condition. If your child could avoid exposure to all of his or her allergies (such as house dust, molds, pets, etc), he or she might still have asthma; however, the severity would be lessened.
Trigger factors, such as viral respiratory infection and running, could still provoke asthma symptoms. Whenever possible, your child should avoid such trigger factors as cigarette smoke and other inhaled irritants.
The degree of control varies with each child as some children with severe asthma are extremely difficult to control.
Control of asthma begins by learning which trigger factors are important to your child. Since no two children with asthma are alike, an individualized comprehensive evaluation must be made of your child to determine his or her trigger factors. The child's history is by far the most important part of the evaluation.
Drinking Water Contaminants
What are drinking water contaminants?
Although drinking water often picks up low levels of some contaminants as it flows in rivers and collects in aquifers, these materials usually are not detected at harmful levels. Public water suppliers must monitor their water to make sure it complies with science-based public health standards. The United States Environmental Protection Agency sets these maximum allowable levels of contaminants in drinking water under the Safe Drinking Water Act. EPA has set standards for 90 contaminants.
ADEQ oversees drinking water system compliance and enforces compliance if the system is not meeting EPA standards. These standards are designed to protect against adverse health effects from contaminants in drinking water while taking into account technical feasibility of meeting the standard. Maximum Contaminant Levels or MCLs have been adopted for more than 80 microbial contaminants, chemicals, and radionuclides.
Children are particularly sensitive to microbial contaminants (such as bacteria and viruses) because their immune systems may be less well developed than those of most adults.
How can drinking water contaminants affect children's health?
Microbial contaminants (such as bacteria and viruses) are of special concern because they may cause immediate, or acute, reactions, such as vomiting or diarrhea. Long-term exposure to some contaminants (such as pesticides, minerals, and solvents) at levels above standards may cause gastrointestinal problems, skin irritations, cancer, reproductive and developmental problems, and other chronic health effects. If a public water system obtains water from a highly contaminated river, lake, or ground water well, it may have difficulty treating the water to meet current safety standards. If contamination poses an immediate health threat, water suppliers are required by law to notify customers right away. Any violation of a drinking water standard requires public notice.
How might children be exposed to drinking water contaminants?
Actual events of serious drinking water contamination are infrequent and usually of short duration. However, treatment problems or extreme weather events may allow contaminants to enter water supplies. In most situations, contaminants are found at levels that do not pose immediate threats to public health.
How can I protect my child from exposure to drinking water contaminants?
Learn about your local drinking water: Start by reading your Consumer Confidence Report, available from your water supplier, to learn whether your water system meets all drinking water standards. Understand how your local water supplier is working to provide your community with safe drinking water. Don't be afraid to ask questions.
Consider the source: Get to know the source of your drinking water, and get involved in activities to protect it. Drinking water source protection is a low-cost means to providing a vital resource. Here are a few simple things you can do to help keep pollution out of the river, lake, stream or aquifer that is your drinking water source:
- Take used motor oil to a recycling center. If you let it drain into a storm sewer or bury it in the trash, it can leak into lakes, rivers and wells. Just one pint of used motor oil can expand over great distances and cause adverse effects to human health and the environment.
- Properly dispose of toxic household trash. For example, batteries contain lead and mercury. Some household cleaners also contain substances that contaminate water. Many communities have special collection sites for these items.
- Do not dispose of chemicals into septic systems, dry wells, stormwater drainage wells or other shallow disposal systems that discharge to ground water.
- Find out what your community is doing to protect your water source and get involved. Work with schools, civic groups and others to start a protection program.
Return to Arizona Children's Environmental Health Program Home Page