A Silent Pandemic

More research is needed to determine which common industrial chemicals harm kids. By Alisa Opar


Millions of children worldwide are exposed to industrial chemicals that could be impairing their brain development, researchers report in the latest issue of The Lancet.

Today, one in every six children worldwide has a developmental disability, which usually affects the nervous system. Though the causes of these neurodevelopmental disorders, such as cerebral palsy, autism, and attention deficit disorder, are largely unknown, scientists have pinpointed a few industrial chemicals as culprits.

But there may be more.

Further research is required to determine how other chemicals affect kids’ brains, says Pierre Grandjean, lead author of the paper. The authors reviewed recent research on hazardous substances. They found that 201 industrial chemicals, including solvents, metals, and pesticides, are known to be toxic to the adult human brain. But when they looked for documentation on how children are affected, they discovered a lack of research. Only five of these chemicals—lead, methylmercury, arsenic, PCBs, and toluene—are known to harm brain development in children and fetuses.

About half of the chemicals the authors looked at are commonly used in industry, and pose a threat to humans when they make their way into the environment. For example, methylmercury released into Minamata Bay in Japan by a plastics plant accumulated in fish, which were caught and eaten by local residents. Infants born to mothers who consumed the fish suffered from various disabilities, including mental retardation, whereas adults were less seriously affected, if at all.

“Small amounts of chemicals that may be innocuous to adults can have debilitating effects on a fetus or small child,” said Grandjean in an email. “We can live a healthy life with just one kidney, but a slight loss of brain function can seriously impact on our quality of life, our education, and economic productivity.”

As a result, we are experiencing what Grandjean calls a ‘silent pandemic’.

“It's a pandemic because it probably affects millions and millions of children today, just like lead pollution from gasoline affected a whole generation of children in the U.S. It's silent because most of the children are not ‘sick’, they don't have a diagnosis, they just don't function as well as they could have,” he says.  

A legal mandate requires testing of toxic substances in the U.S., but it is poorly enforced.

The authors urge a precautionary approach, like the one the European Union recently adopted: If researchers find that a chemical has a potentially serious toxic effect, lawmakers would put in place strict regulations that could later be relaxed, if the chemical is less harmful than anticipated. Doing so, say the authors, could help prevent neurodevelopmental disorders that arise from environmental exposure to chemicals.