The number of industrial chemicals in widespread use recognized to cause childhood brain impairments has more than doubled since 2006, scientists said Friday.
Researchers at the Mount Sinai Hospital and Harvard School of Public Health cited six broad groups of toxins in 2006 as having a direct impact on human brain development. Now, they have identified another six, which include metals and inorganic compounds, pesticides and dangerous solvents.
Based on their examination of chemicals that are widely used -- but untested for human safety -- the scientists concluded that fetal and early childhood exposures have grown into a silent pandemic of neurodevelopmental disorders, such as autism, attention-deficit hyperactivity disorder, dyslexia and even losses in IQ points.
Some of the brain-damaging compounds, they say, waft through the air of countless homes as house dust.
"These are chemicals that Americans are exposed to on a regular basis," said Dr. Philip Landrigan, chairman of preventive medicine at Mount Sinai's Icahn School of Medicine in Manhattan and director of the Children's Environmental Health Center at the hospital.
In the first study Landrigan and colleagues named arsenic, arsenic-based compounds, lead, methylmercury, toluene and polychlorinated biphenyls -- PCBs -- as key brain-damaging culprits. That list was culled from a longer one containing 202 brain-damaging chemical suspects.
This time, they have identified the pesticides DDT, DDE and chlorpyrifos; industrial fluorides and manganese; brominated diphenyl ethers, used as flame-retardants; and tetrachloroethylene, commonly known as PERC, a colorless fluid widely used in dry cleaning.
Landrigan and Dr. Philippe Grandjean of Harvard report their research in The Lancet Neurology.
"Brominated diphenyl ethers are flame retardants and very widely used in carpets, draperies, furniture upholstery and computer cases," Landrigan said. "This stuff gets into house dust and into people."
Even though the pesticide DDT was banned in this country nearly a half-century ago, it is still widely used throughout Latin America in agriculture, Landrigan added.
Rising produce imports from Mexico and elsewhere increase the exposure to DDT even without its active use in this country, he said.
PERC has infiltrated groundwater on Long Island and beyond, studies have shown.
In November, a Roosevelt community group -- Choice For All -- held a community meeting to rivet public attention on PERC in the Centennial Avenue area, the former site of uniform and linen supply companies.
The site has been listed on the state Department of Environmental Conservation's registry of inactive hazardous waste sites in July 2005.
PERC is not only a central nervous system toxin, but also is suspected of affecting the liver, kidneys, immune system and reproductive organs.
"Current chemical regulations are woefully inadequate to safeguard children whose developing brains are uniquely vulnerable to toxic chemicals in the environment," Grandjean said.
He is calling for a new law requiring manufacturers to prove that existing industrial chemicals and new ones introduced for public use in the future are tested for safety and proved to be nontoxic.