Brain pollution: Common chemicals are damaging young minds

Learning disabilities. Cerebral palsy. Mental retardation. A "silent pandemic" of these and other neurodevelopmental disorders is under way owing to industrial chemicals in the environment that impair brain development in fetuses and young children. That's the conclusion of a data analysis by researchers at the Harvard School of Public Health (HSPH) and the Mount Sinai School of Medicine, who point to 201 chemicals - most of them common - known to inflict lasting neurological damage in humans. Information on possible neurotoxic effects exists, however, for only a small fraction of the thousands of chemicals in use around the world.

The findings, published online in The Lancet (Nov. 8, 2006) and soon to be in print, stem from a careful review of publicly available data by lead author Philippe Grandjean, an adjunct professor in HSPH's Department of Environmental Health, and Philip Landrigan, a professor of pediatrics and chair of Community and Preventive Medicine at Mount Sinai. Their research was funded by the Danish Medical Research Council and, in the United States, by the National Institute of Environmental Health Sciences and the Environmental Protection Agency.

In their report, the researchers urge countries to adopt the "precautionary" approach for chemical testing and control recently embraced by the European Union (EU). The EU has put into place strong regulations that can later be relaxed if a potential hazard proves less dangerous than anticipated, instead of requiring a high level of proof of toxicity at the outset. By contrast, U.S. requirements for the testing of chemicals for brain toxicity are minimal, the authors say.

One out of six American children has a developmental disability, usually involving the nervous system, according to the U.S. Centers for Disease Control and Prevention. A growing body of evidence links industrial chemicals to neurodevelopmental disorders; treatments for such disorders are difficult and costly to families and society. Lead, for example, became the first substance identified as having toxic effects on early brain development only about 100 years ago, even though its neurotoxicity in adults had been known for centuries.