Picturing pesticides' impacts on kids

by J. Raloff

Heavy exposure to pesticides appears to have impaired child development in a Yaqui Indian community in Mexico, a new study finds. However, observes Elizabeth A. Guillette, the University of Arizona anthropologist who led the research, "I don't think the kids' exposures are either more or less than might occur in other agricultural areas" -- even in the United States.

Seven years ago, researchers at the Technological Institute of Sonora in Obregón, Mexico, showed that children in Sonora's Yaqui Valley are born with detectable concentrations of many pesticides in their blood and are exposed further through breast milk. Valley farmers apply pesticides 45 times per crop cycle, and they grow one or two crops per year. Area families also tend to use household bug sprays daily. In the new study, Guillette and the Obregón team screened preschoolers for possible behavioral effects of such exposures.

They recruited 33 children from the valley and another 17 from Yaqui ranching villages in the nearby foothills, where families swat indoor bugs and avoid using agricultural chemicals to control garden pests. The foothills' only major exposure to pesticides comes from government spraying of DDT to control malaria.

The scientists asked 4- and 5-year-olds to jump up and down as long as possible, catch balls, drop raisins into bottle caps, perform memory drills, and draw pictures of people. In the June Environmental Health Perspectives, they report that valley children demonstrated significantly less stamina, gross and fine eye-hand coordination, 30-minute recall, and drawing ability than preschoolers from the foothills communities.

"I know of no other study that has looked at neurobehavioral impacts -- cognition, memory, motor ability -- in children exposed to pesticides," says neurotoxicologist David O. Carpenter of the State University of New York at Albany. "The implications here are quite horrendous," he says, because the magnitude of observed changes "is incredible -- and may prove irreversible."

"Though the children exhibited no obvious symptoms of pesticide poisoning, they're nevertheless being exposed at levels sufficient to cause functional defects," observes pediatrician Philip J. Landrigan of Mount Sinai Medical Center in New York.

"To ignore these data would not be sound," concludes Landrigan, who is directing the development of the new federal Office of Children's Health Protection.

From Science News, Vol. 153, No. 23, June 6, 1998, p. 358.
Copyright Ó 1998 by Science Service.

copyright 1998 ScienceService