The Cognitive and Mental Health Risks of Child Exposure to Environmental Toxins

Posted on: March 4th, 2016 by

After the recent water crisis in Flint, Michigan—described recently in another blog by CHRC’s Patrick CoatarPeter—the issue of environmental toxin exposure, disproportionately experienced by underserved communities and individuals of color, has again risen to the public’s attention. The CHRC has identified children’s environmental health, including possible exposures to these toxins, as one of three priority areas in children’s rights, and has hosted a summit and several guest speakers on the issue. However, we continue to feel that more public awareness around these exposures is necessary, as they represent a grave but preventable threat to the health and rights of children.

According to the Agency for Toxic Substances and Disease Registry, children are often most at risk of exposure to environmental toxins, and are also particularly susceptible to the damage they may cause. Children physiologically need more air, water, and food per pound of bodyweight than adults, and tend to touch, mouth, and taste all things in their path, some of which may be a source of toxins. Furthermore, research shows that at various developmental stages, from gestation to adolescence, when important neural and endocrine circuits are forming, youth may be particularly susceptible to damage caused by toxins.

It would seem that one of the government’s primary responsibilities is to protect the health of citizens, particularly children. Unfortunately, Physicians for Social Responsibility reports that government policy to research existing chemicals to determine whether or not they may be toxic at current levels of exposure is lacking, with tens of thousands of chemicals released into the environment with no studies on their effects on developing children. Sadly, America lags behind other developed countries in regulating these substances: a report by the Environmental Defense Fund reports that both Canada and Europe’s policies for research on the potential effects of chemicals are much more extensive.

The impact of environmental toxins on child health continues to be a topic of research. However, what research that does exist has shown that exposure to even low levels of some toxins may have a negative impact on physical health, citing increased rates of asthma, childhood obesity and childhood cancers. Perhaps even more insidious and damaging, however, is the potential for toxins to negatively impact children’s mental health and intellectual capabilities. In fact, the National Academy of Sciences has determined that environmental factors contribute to 28% of developmental disorders (e.g. autism, ADHD, intellectual disability) in children. Below is a discussion of some of the most common toxins that may affect a child’s mental development.

Children’s exposure to lead has been a centuries-long battle for individuals concerned with children’s rights. Lead is present in some older paints, pipes, and may leach into drinking water as demonstrated in Flint, MI. Exposure to lead has been demonstrated to predict oppositional and behavioral problems, as well as decreases in IQ, math and reading scores. It is known that there is no safe level of exposure, with even slight increases in blood lead levels having damaging consequences. Exposed children may have difficulty with learning and school performance, permanently impacting their academic success.

Another example of a metallic toxin that may impact children’s mental health is mercury. Metallic mercury is used for several industrial purposes, including the creation of fluorescent lightbulbs, some batteries and mercury thermometers. Metallic mercury is widely available in schools as part of science curricula, and can be particularly attractive to children given its silvery color. Chronic exposure to metallic mercury vapors may cause irritability, impulsiveness, and impaired memory. In addition, organic mercury can be found at some levels in fish and shellfish, with increasing mercury present as fish move up the food chain. Exposure to high levels of organic mercury via contaminated fish, particularly in utero, is correlated with loss of IQ and permanent brain damage. Across the world there have been cases in which the inhabitants of entire geographic areas are affected by mercury exposure through industrial pollution, accidental mercury spills, and contaminated seafood, and each has shown that mercury’s effects on children’s intellectual development are permanent and damaging.

A final category of toxins that may impact children’s mental health is pesticides, or chemicals used to prevent, destroy, or repel unwanted pests on crops or in the lived environment. Exposure to pesticides can come from eating pesticide residues on foods, or inhaling airborne pesticides applied to crops nearby. However, a child may also be exposed to pesticides in the home or school, if they are applied to prevent roaches or other home pests. The outcomes of pesticide exposure are complex, as the chemicals used are highly diverse. However, many have been linked to delayed intellectual development. In fact, Dr. David Bellinger of Harvard Medical School estimated that 16.9 million IQ points have been lost in children due to intra-uterine exposure to organophosphates, the most common pesticides used in agriculture.

Unfortunately, this is not an exhaustive list of the environmental toxins that may impact children’s mental health, nor does it include the large number of the toxins that may have an impact on children’s physical health. For more information about other exposures and what you can do to prevent them, see the following resources:

Physicians for Social Responsibility’s Pediatric Environmental Health Toolkit

Mt. Sinai Hospital’s List of Toxins that May Affect your Child

National Institute of Health’s Household Products Database

Environmental Protection Agency’s Substance Registry Services

The Advancing Healthy Homes and Healthy Communities Initiative’s 2014 Summit Report

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