Kids and Contaminants
Fire Retardants in Toddlers and Their Mothers: Kids and Contaminants
"At first it was upsetting to know that Ruby had fairly high levels of PBDEs in her body. But it becomes even more upsetting when you think about the implications for all our children. There's nothing about our lifestyle that would put us at risk. If our levels are high, then yours probably are, too." Katrina Alcorn, study participant.
Children are particularly vulnerable to the toxic effects of harmful chemicals for a number of reasons. Their normal behaviors lead them to explore their local environment in ways that increase their exposures to toxic chemicals that may reside in everyday items like carpeting, furniture, electronic items and other common consumer products. Their small size leads to more food and water consumption, dermal exposure and higher inhalation rates than adults. They also have dietary patterns that differ greatly from adults, leading them to disproportionately high exposures from chemical contaminants in certain types of foods and beverages. Finally, their developing biological systems are not able to respond to environmental exposures in the same manner as adults, leading to a decreased ability to effectively detoxify once they have been exposed to toxic chemicals (Moya 2004). Public health protections for toxic chemicals often fail to consider these special factors and put our children at risk.
Children at play
Children, as they are familiarizing themselves with their local environment, often handle everything around them and then place their hands into their mouths. This hand-to-mouth behavior is perfectly normal but places them at risk from chemical contaminants in soil, dust, and carpeting (Landrigan 1995). In addition, they handle toys and other objects and then lick their fingers or place these objects in their mouths, leading to ingestion of toxic chemicals that may reside in these products (Moya 2004). One study estimates that children ages 4 and younger put their hands in their mouths on average 16 to 18 times per hour (Tulve 2002). Children also play close to the ground, where they are exposed to chemical contaminants that find their way into grass and soil and that are found in dust that may coat indoor surfaces such as floors and carpets (Moya 2004). In general, these types of activities lead to exposure through ingestion and inhalation, but dermal exposures are also a concern, especially when it comes to soil contaminants, since soil can adhere to skin long after direct contact has ceased (Moya 2004).
Children eat more food and drink more water per unit of body weight than do adults (Landrigan and Carlson 1995). This means that kids have higher exposures to toxic chemicals that contaminate commonly consumed foods, beverages, and drinking water in comparison to adults (Landrigan and Carlson 1995). Children also often have a less varied diet than adults since kids often have specific food and beverage preferences and are not eager to try new foods. This means that children’s consumption of certain foods and beverages is disproportionately high in comparison with adults; for example, U.S. Department of Agriculture surveys have shown that kids consume more dairy products and produce items per unit of body weight than adults (Moya 2004). With respect to produce items, closer analysis has shown that young children eat more than twice the amount of common fruits and vegetables like carrots, broccoli, and grapes when compared with adults, leading to higher pesticide exposures among kids (NRC 1993). Children also consume more water per unit of body weight than adults do. Tap water testing by utilities across the United States has found hundreds of chemical contaminants, including pesticides, heavy metals, and endocrine disruptors (EWG 2005). Children, on average, drink from 2 to 5 times the amount of water per unit of body weight than do adults (Moya 2004). Babies who are fed powdered or concentrated liquid formula ingest large amounts of tap water over the course of their first year. These facts result in significantly higher exposures to tap water contaminants among children.
The human body has certain biological mechanisms in place to metabolize and detoxify toxic chemicals. In children, these biological mechanisms are still developing and their immature organ systems do not have the same capacity as adults to metabolize and excrete toxic chemicals. For example, liver enzymes are critical in the process of detoxification; in children, these enzyme systems are not fully developed, leading to a decreased ability to effectively deal with toxic chemical exposures (EPA 2007).
In addition, children’s organ systems are also rapidly developing during childhood; exposure to toxic chemicals during these periods of rapid development could lead to permanent and irreversible damage to these organ systems. This is especially true for the brain and nervous system, which are particularly vulnerable to toxic chemicals since they do not have good repair systems in place once structural damage has occurred. Exposure to nervous system toxins during childhood can decrease intelligence and cause behavioral problems. Lead poisoning is a classic example of a toxin that poses unique risks to children. The body's protective blood-brain barrier forms over the first 5 to 7 years. Prior to that, low level lead exposures can permanently damage the nervous system, lower IQ and cause behavioral challenges (EPA 2008e). Economists calculate that even the subtle deficits cause by low level lead poisoning tally up to billions of dollars in direct costs to society. These include lost wages, social services, and educational interventions. Clearly these findings should lead us to invest up-front in assessing new chemicals for their ability to harm children's development. While ingestion of toxic chemicals is the most significant route of exposure for children, dermal and inhalation exposures are important considerations with certain chemicals like pesticides. Children play close to the ground in activities that involve contact with soil and dust. Kids also have higher surface area when compared with adults so dermal exposures can be more significant in children (EPA 2007). As a result, the potential dose of a chemical following dermal exposure is estimated to be about 40 percent greater in children than adults. Children have higher rates of inhalation than adults because of higher metabolic rates, leading to greater exposure to toxic air pollutants. Children’s unique behaviors and physiology make them particularly vulnerable to environmental exposures. Once these exposures have occurred, their immature organ systems may become irreversibly damaged and unable to detoxify and excrete toxic chemicals as effectively as adults. Unfortunately, most state and national biomonitoring programs do not include young children, leaving huge deficiencies in our understanding of how toxic chemicals may affect them. These deficiencies must be adequately addressed when lawmakers and scientists propose safety standards for chemicals because it is clear that standards that protect adults may not necessarily protect children.
Children's diseases on the rise
Recent U.S. health trends among children raise concerns about the role of environmental exposures in increasing rates of certain chronic diseases. Asthma rates doubled from 3.6 to 7.5 percent from 1980 to 1995, and these rates have continued to increase. The EPA estimates that 9.3 percent of children suffered from asthma in 2006 (EPA 2008f). Neurodevelopmental disorders among children have also increased in recent years, with autism now affecting 1 in 150 children and ADHD diagnosed in 1 of every 15 children ages 5 to 17. Cancer in children increased by 33 percent from 1975 to 2005 but thankfully, mortality rates decreased by almost half during that time period due to better treatment options (EPA 2008f). Acute lymphocytic leukemia and brain cancer incidences have particularly seen increases among children from the 1970’s to the 1990’s. These types of increases in chronic diseases among children are worrisome but unfortunately not unexpected given their unique vulnerabilities to environmental exposures and the overabundance of toxic chemicals in our air, tap water, food, and local environments. The U.S. needs effective national chemical policies that take into account children’s unique behaviors, diets, and biology in order to minimize the effects of toxic chemicals on their health.