According to a recent study, exposure to industrial chemicals is causing a 'silent pandemic' of brain disorders affecting millions of kids across the globe.
This study was published on Tuesday in the British medical journal, the Lancet.
Developmental disability affects 1-in-6 children and most of the cases are disorders of the nervous system.
The scientists say that disorders like autism, attention deficit disorder, cerebral palsy and developmental delays can be associated with exposure to toxic industrial chemicals during the development of the fetus.
"The bottom line is you only get one chance to develop a brain," Philippe Grandjean, M.D., of the Harvard School of Public Health, and lead author said. "We have to protect children against chemical pollution because damage to a developing brain is irreversible."
"The human brain is a precious and vulnerable organ. And because optimal brain function depends on the integrity of the organ, even limited damage may have serious consequences," he said.
Grandjean and co-author Philip Landrigan, M.D., of New York's Mount Sinai School of Medicine have identified 201 chemicals that have toxic effects on the human brain. These chemicals include metals, solvents and pesticides. According to them, only 5 of these chemicals have been proven to have a harmful effect on developing brains including lead, mercury, arsenic, PCBs, and toluene.
Grandjean and Landrigan have spent decades on studying the toxic effects of exposure to mercury and lead respectively on the developing brain.
Toxic chemicals affect developing brains to a larger extent than the developed brain of the adults. The blood-brain barrier, which provides protection from the effect of several toxic chemicals, is not fully developed in the infants till the age of 6 months.
A number of pesticides and industrial chemicals that accumulate in the breast tissue are passed on to the infants when they are breast-fed by their mother. The infants' exposure levels are 100 times higher than that of their mothers'.
The study revealed that the rate of brain development disorders was higher among the preschool kids in the agricultural communities than their counterparts in the urban communities. This was due to the increased level of exposure to pesticides.
Parkinson's disease and other neurodegenerative diseases in adults could also be a delayed consequence of exposure to toxic chemicals.
Steps have been taken by bringing about several prevention programs like elimination of lead additives in gasoline. Several hindrances to such programs have been identified in this study.
The authors say, "Of the thousands of chemicals on the market, fewer than half have been subjected to even token laboratory testing for toxicity." New chemicals should be tested for their effect particularly, on the nervous system before they are available commercially.
Though most of the scientists are in favor of this study, some feel that this study has not considered the levels of exposure of the affected kids and if there is any safe level of exposure.
Warren Foster, director of the Centre of Reproductive Care at Ontario's McMaster University, said, "These findings do not mean a ban on chemicals is necessary or helpful.
"We still need coolants, we still need plasticizers, we still need flame retardants, and we still need solvents. So if we ban these, they're going to be replaced with something else. And just because something else comes along that we know nothing about doesn't mean it's safer.''