Researchers found that exposure during pregnancy to pesticides called organophosphates – used on food crops – may impair child cognitive development.
They found that every tenfold increase in measures of organophosphates detected during a mother’s pregnancy corresponded to a 5.5 point drop in overall IQ scores in children by the age of seven.
Children in the study with the highest levels of prenatal pesticide exposure scored seven points lower on a standardized measure of intelligence compared with children who had the lowest levels of exposure.
The study was based on the children of more than 400 women from Harlem, New York – implying that exposure was from eating fruit and vegetables sprayed with pesticides, rather than directly from the environment.
Brenda Eskenazi, professor of maternal and child health at University of California, Berkeley, described the impact as “substantial”.
She said: “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.”
Organophosphates are commonly used on crops in Britain, although some only with stringent limitations.
Georgina Downs, of the UK Pesticides Campaign, said: “It is widely acknowledged that organophosphates can cause serious neurological and cognitive impacts on humans which is not surprising considering that they are deliberately designed to be neurotoxic.”