Pesticide exposure linked to Lower Intelligence


A new study published on the Proceedings of the National Academy of Sciences found that when pregnant women are exposed to moderate levels of a common pesticide knows as Chlorpyrifos or CPF, their children tend to experience changes in the structure of their brains. These changes, the study says, are long lasting and often result in lower levels of intelligence.

“Prenatal exposure to chlorpyrifos (CPF), an organophosphate insecticide, is associated with neurobehavioral deficits in humans and animal models. We investigated associations between CPF exposure and brain morphology using magnetic resonance imaging in 40 children.”

The study published on Monday links exposure to this and other commonly used chemicals to the depletion of the brain. The chemicals which are widely used all over the world, but more specifically in agricultural areas, are usually in products like pesticides and commercial pest control brands. The study analyzed the exposure of pregnant women in New York City, who were particularly tested for CPF.

The number of women included in the study was 369 in total. The observations were done before 2001, when CPF was officially banned from US household use, although it continues to be used worldwide in agricultural products. During the investigation, researchers compared 20 children ages 5 to 11, with mothers that had been exposed to CPF. The findings concluded that there were significant abnormalities in brain structure when those 20 children were compared to others from mothers who had had low exposure.

All test subjects, the study says, were exposed to levels below the amounts established by US laws. This indicates that even in low amounts, the consequences of direct contact with CPF an similar chemicals can be devastating for both the mother and the child. The results are very meaningful harm to children brain development which in most cases impairs them from having a completely well-functioning brain. “The present study provides evidence that the prenatal period is a vulnerable time for the developing child,” warns Virginia Rauh, professor at the Mailman School of Public Health and Deputy Director of the Columbia Center for Children’s Environmental Health, who is also the lead investigator of the study.

“Toxic exposure during this critical period can have far-reaching effects on brain development and behavioral functioning,” she added. Experiments were aided by magnetic resonance imaging (MRI) technology to scan children’s brains. The scans show that parts of the brain are abnormally larger than usual and that some physical differences between male and female brain structured had changed after being exposed to high levels of CPF containing pesticides.

Although researchers recommend further study of the long-term effects of CPF in children, they have concluded that the images do show deficits in IQ which match those previously reported in children who have been exposed to chemicals like the ones being tested for in this experiment. “By combining brain imaging and community-based research, we now have much stronger evidence linking exposure to chlorpyrifos with neurodevelopmental problems,” said author Bradley Peterson, chief of Child and Adolescent Psychiatry, New York State Psychiatric Institute.

Although the use of CPF was banned in 2001, the product continues to be used in food crops that may be imported to the US and other parts of the world, as well as wood, golf courses, parks, highways and so on. Although exposure is now much lower than before 2001, there still great potential for mothers who are pregnant to be exposed to CPF, even if they live far away from agricultural areas of the world. “In the past, high CPF exposure was associated with enlargement of superior temporal, posterior middle temporal, and inferior postcentral gyri bilaterally,                     and enlarged superior frontal gyrus, gyrus rectus, cuneus, and precuneus along the mesial wall of the right hemisphere,” say the authors.

Overall, the study conclusively shows clear associations between prenatal exposure to environmental neurotoxicant(s), at permitted levels and structural changes in the developing human brain.

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