Dr. Philip Landrigan at Mount Sinai School of Medicine in New York and Dr. Philippe Grandjean from Harvard School of Public Health in Boston, authors of the review published Friday in The Lancet Neurology journal, say the news is so troubling they are calling for a worldwide overhaul of the regulatory process in order to protect children's brains.
"We know from clinical information on poisoned adult patients that these chemicals can enter the brain through the blood brain barrier and cause neurological symptoms," said Grandjean.
"When this happens in children or during pregnancy, those chemicals are extremely toxic, because we now know that the developing brain is a uniquely vulnerable organ. Also, the effects are permanent."
The two have been studying industrial chemicals for about 30 years. In 2006, they published data identifying five chemicals as neurotoxicants -- substances that impact brain development and can cause a number of neurodevelopmental disabilities including attention-deficit hyperactivity disorder, autism, dyslexia and other cognitive damage, they said.
Those five are lead, methylmercury, arsenic, polychlorinated biphenyls, or PCBs, and toluene.
Banned in the United States in 1979, PCBs were used in hundreds of products including paint, plastic, rubber products and dyes. Toluene is in household products like paint thinners, detergents, nail polish, spot removers and antifreeze.
Now, after further review, six more chemicals have been added to the list: manganese; fluoride; tetrachloroethylene, a solvent; a class of chemicals called polybrominated diphenyl ethers, or flame retardants; and two pesticides, chlorpyrifos, which is widely used in agriculture, and dichlorodiphenyltrichloroethane, or DDT.
"The continuing research has identified six new chemicals that are toxic to the developing human brain," said Landrigan. "We're turning up chemicals at the rate of about one a year that we're discovering are capable of damaging the developing brain of a human fetus or human infant." Read More