A new review published in The Lancet Neurology stresses the importance of a global overhaul of regulations regarding industrial chemicals, as experts warn that child exposure to such toxins could be causing a "silent epidemic" of brain development disorders worldwide.
According to Dr. Phillippe Grandjean, of the Harvard School of Public Health in Boston, MA, and Dr. Phillip Landrigan, of the Mount Sinai School of Medicine in New York, the number of chemicals that are recognized to be linked with neurodevelopmental disorders has increased from six to 12.
In 2006, lead, methylmercury, arsenic, polychlorinated bipenyls and toluene were the only chemicals linked to brain development disorders.
By last year, manganese, fluoride, chlorpyrifos (a pesticide), dichlorodiphenyltrichloroethane (DDT), tetrachloroethylene (a solvent), and the polybrominated diphenyl ethers (flame retardants) were added to the list.
Furthermore, the experts note that the number of chemicals that have been associated with human brain damage - but have not been regulated to protect children's health - has increased from 202 in 2006 to 214 in 2013.
They note that these chemicals can be found in everyday items, such as toys, furniture and clothes.
The experts say there is increasing evidence that exposure to such chemicals may be a cause of neurodevelopmental disorders, such as attention deficit hyperactivity disorder (ADHD), autism, cerebral palsy and dyslexia.
Lack of chemical testing 'worrying'
Researchers say that lack of safety testing and regulation surrounding industrial chemicals may be causing a global "silent epidemic" of brain development disorders.
However, they note that there are many more chemicals that have not been tested for toxicity, which is a concern.
"The vast majority of the more than 80,000 industrial chemicals in widespread use in the US have never been tested for their toxic effects on the developing fetus or child," they write.
"Exposure to these chemicals during early development can cause brain injury at levels much lower than those affecting adults, and the real impact on children's health is just beginning to be uncovered."
The experts say that failing to test chemicals for their neurodevelopmental toxicity, and the large amount of evidence needed before certain chemicals are regulated, are factors that are putting children's health at risk.
"The total number of neurotoxic substances now recognized almost certainly represents an underestimate of the true number of developmental neurotoxicants that have been released into the global environment.
Our very great concern is that children worldwide are being exposed to unrecognized toxic chemicals that are silently eroding intelligence, disrupting behaviors, truncating future achievements, and damaging societies, perhaps most seriously in developing countries."
Onus 'should be on chemical producers' to demonstrate product safety
The experts recommend a new international prevention strategy - chemical producers should have to show that their products are at low risk of toxicity instead of the government.
Furthermore, they say a new international regulatory agency should be formed to ensure testing of these products is carried out before entering the market.
"The only way to reduce toxic contamination is to ensure mandatory developmental neurotoxicity testing of existing and new chemicals before they come into the marketplace," says Dr. Landrigan.
"Such a precautionary approach would mean that early indications of a potentially serious toxic effect would lead to strong regulations, which could be relaxed should subsequent evidence show less harm."
Dr. Grandjean adds that until such precautions are put in place, "we are facing a pandemic of neurodevelopmental toxicity."
Medical News Today recently reported on a study suggesting that low-level pesticide exposure may increase the risk of Parkinson's disease, while other research suggests that a byproduct of DDT may increase the risk of Alzheimer's disease.