Berkeley, CA—Researchers at University of California’s Berkeley School of Public Health believe that prenatal exposure to organophosphate (OP) pesticides is linked to lower intelligence scores in children.

This study is one of three papers on the topic and recently was published in Environmental Health Perspectives. The other studies yielded similar results and were completed at Columbia University and Mt. Sinai Medical Center. They studied urban populations whereas the aforementioned study focused on children who lived in agricultural town Salinas, CA. According to researchers, “It is very unusual to see this much consistency across populations in studies, so that speaks to the significance of the findings.”

The California trial involved 329 children and was lead by Maryse Bouchard, who was a post-doctoral researcher at study time. OP pesticide exposure was gauged by measuring dialkyl phosphate (DAP) metabolites in mothers’ urine during pregnancy. Urine samples were obtained twice during pregnancy and regularly after birth from children between six months and five years of age. Once the children were seven years old, they were given the Wechsler Intelligence Scale for Children-IV to measure perceptual reasoning, processing speed, working memory and verbal comprehension.

Study results show that for every 10-fold increase in OP found during pregnancy, there was a five-point plummet in IQ scores. And, children in the trial with the highest levels of prenatal pesticide exposure averaged seven points lower on a standardized intelligence test than children who had the lowest level of exposure.

Say the authors, “That difference could mean, on average, more kids being shifted into the lower end of the spectrum of learning, and more kids needing special services in school.”

Published in WholeFoods Magazine, July 2011