By Janet Raloff
Children exposed in the womb to substantial levels of neurotoxic pesticides have somewhat lower IQs by the time they enter school than do kids with virtually no exposure. A trio of studies screened women for compounds in blood or urine that mark exposure to organophosphate pesticides such as chlorpyrifos, diazinon and malathion.
These bug killers, which can cross the human placenta, work by inhibiting brain-signaling compounds. Although the pesticides’ residential use was phased out in 2000, spraying on farm fields remains legal.
The three new studies began in the late 1990s and followed children through age 7. Pesticide exposures stem from farm work in more than 300 low-income Mexican-American families in California, researchers from the University of California at Berkeley and their colleagues report. In two comparably sized New York City populations, exposures likely trace to bug spraying of homes or eating treated produce.
Among the California families, the average IQ for the 20 percent of children with the highest prenatal organophosphate exposure was seven points lower compared with the least-exposed group.
Read full post at Wired Science