Number of Chemicals Known to Injure Developing Brain Doubles in 7 Years, According to Mount Sinai and Harvard Researchers

Share Article

Number of Chemicals Known to Injure the Developing Brain Doubles in Seven Years, According to Mount Sinai and Harvard Researchers

"More must be done to close the gap in testing of chemicals for neurodevelopmental neurotoxic effects; strengthen government regulation of these chemicals; and educate the public about the absolute harm these chemicals do." -- Philip Landrigan, MD

The number of industrial chemicals recognized as causing neurodevelopmental disabilities, including autism, attention-deficit hyperactivity disorder (ADHD), dyslexia, and other cognitive impairments, have more than doubled in the seven years since a landmark study of these toxins was first published, according to new findings from Mount Sinai and the Harvard School of Public Health. The Review, titled “Neurobehavioral Effects of Developmental Toxicity,” is published in this month’s edition of The Lancet Neurology and is co-authored by Philip J. Landrigan, MD, MSc, the Ethel H. Wise Professor of Preventive Medicine, Chair, Department of Preventive Medicine, and Director of the Children's Environmental Health Center at the Icahn School of Medicine at Mount Sinai, and Philippe Grandjean, MD, Professor and Chair of Environmental Medicine at Harvard School for Public Health. The work was supported by the National Institute for Environmental Health Sciences, part of the National Institutes of Health.

For full Review, see:


“Recent events, such as the chemical spill in to West Virginia’s Elk River and the continuing debates over hydrofracking, have certainly raised the public’s awareness over toxic chemicals and their effects on our health and well-being. But more alarming is that in only seven years, the number of industrial chemicals recognized to have impacts on brain development have doubled, leading to a global, silent epidemic of neurodevelopmental disabilities,” said Dr. Landrigan of Mount Sinai. “More must be done to close the gap in testing of chemicals for neurodevelopmental neurotoxic effects; strengthen government regulation of these chemicals; and educate the public about the absolute and irreversible harm these chemicals do.”

In 2006, Dr. Grandjean and Dr. Landrigan first published the results of a comprehensive analysis that identified that identified five industrial chemicals as developmental neurointoxicants: lead, methylmercury, polychlorinated biphenyls, arsenic, and toluene. Since 2006, epidemiological studies have documented six more: manganese, fluoride, chlorpyrifos, dichlorodiphenyl-trichloroethane (or DDT), tetrachloroethylene, and the polybrominated diphenyl ethers. Additionally, the authors wrote, “In our 2006 review, we expressed concern that additional developmental neurointoxicants might lie undiscovered in the 201 chemicals that were then known to be neurotxic human adults, in the roughly 1,000 chemicals known to be neurotoxic in animal species.”

The authors go on to state these impacts in financial terms: pointing to research that shows a correlation between exposure to these chemicals and IQ loss, they estimate that the loss of a single IQ point decreases average lifetime earnings of $18,000 per person; and that the annual costs of childhood lead poisoning and methylmercury toxicity total about $55 billion.

In their Review, Dr. Grandjean and Dr. Landrigan propose a three-pronged strategy to address this growing problem:

1.    Legally mandate testing of existing industrial chemicals and pesticides already in commerce, with prioritization of those with the most widespread use, and incorporation of new assessment technologies;
2.    Legally mandate premarket evaluation of new chemicals before they enter markets, with use of precautionary approaches for chemical testing that recognize the unique vulnerability of the developing brain;
3.    Form a new clearinghouse for neurotoxicity as a parallel to the International Agency for Research on Cancer, (which will) facilitate and coordinate epidemiological and toxicological studies and will lead the urgently need global programs for prevention.”

“Current chemical regulations are woefully inadequate to safeguard children whose developing brains are uniquely vulnerable to toxic chemicals in the environment,” says Dr. Grandjean of Harvard School of Public Health. “Until a legal requirement is introduced for manufacturers to prove that all existing industrial chemicals and all new chemicals are non-toxic before they enter the marketplace, along the lines of the European Union’s Registration, Evaluation, Authorization and Restriction reformed chemicals law, or REACH, we are facing a pandemic of neurodevelopmental toxicity.”

Dr. Landrigan adds “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. 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.”

Share article on social media or email:

View article via:

Pdf Print

Contact Author

Sid Dinsay
The Mount Sinai Medical Center
+1 (212) 241-9200
Email >