Disturbing behavior: neurotoxic effects in children.

A n epidemic of neurobehavioral problems is sweeping through children today. According to In Harm s Way: Toxic Threats to Child Development, a May 2000 report published by the Greater Boston Physicians for Social Responsibility, 12 million American children suffer from learning, developmental, or behavioral disabilities. Specifically, these disabilities may include attention-deficit/hyperactivity disorder (ADHD), autism, learning disabilities, mental retardation, and other neurobehavioral problems. And the prevalence of some of these disabilities may be increasing. In the past few years, much research has examined the factors that make children markedly vulnerable to neurotoxic substances. Although science cannot always pinpoint the cause of neurological disabilities, many investigators believe that exposure to environmental contaminants in utero or soon after birth could be responsible for at least some of these problems. The list of potentially harmful agents covers a wide range-alcohol, lead, manganese, mercury, organophosphate pesticides, environmental tobacco smoke, and more. Per pound of body weight, children eat more food, drink more fluids, and breathe more air than adults, thereby increasing their potential exposure to harmful toxicants. Moreover, some toxic materials may pose a particularly significant threat to the fetus when crucial systems such as the brain and associated nervous systems are under development. Although a host of scientists are now exploring neurodevelopmental problems, the causes of many such problems still remain unknown. Philip J. Landrigan, director of the Mount Sinai School of Medicine's Center for Children's Health and the Environment, says, "We know the cause of only a relatively small minority of these conditions. It depends on whom you talk to, but we know the cause of no more than 10-30%, and 30% ... is being generous."