A research-oriented framework for risk assessment and prevention of Children's exposure to environmental toxicants

Learning disabilities, intellectual retardation, dyslexia, attention deficit/hyperactivity disorder, autism, and propensity to violence affect millions of U.S. citizens and are diagnosed in an estimated 3% of all children born in the United States. The consequences of these neurological, developmental, and behavioral disorders are often tragic; their familial, societal, and economic costs are immense, and the resulting disabilities lifelong. Toxic chemicals in the environment--lead, polychlorinated biphenyls, mercury, and certain pesticides--are now known to cause some fraction of neurodevelopmental disabilities. The implications of this discovery for prevention are potentially enormous; developmental disorders of toxic origin can, in theory, be prevented through the identification, characterization, and elimination of toxic environmental exposures. However, serious impediments to prevention exist: too few chemicals are tested for toxicity to early brain development, knowledge of infants' and children's special vulnerabilities and unique exposures is scant, and paradigms for environmental risk assessment have only begun to address the hazards confronting infants and children.