(Beyond Pesticides, August 25, 2010) Exposure to pesticides while in the womb may increase the odds that a child will have attention deficit hyperactivity disorder (ADHD), according to researchers at the University of California-Berkeley School of Public Health. Maternal metabolites of organophosphate pesticides have previously been associated with neurobehavioral deficits in children.
The California researchers are studying the impact of environmental exposures on the health of women and children who live in the Salinas Valley, an agricultural region with heavy pesticide use. They tested the urine of pregnant women for pesticide residue, and then tested the behavior of their children at ages 3Â˝ and 5. The 5-year-olds who had been exposed to organophosphate pesticides while in the womb have more problems with attention and behavior than did children who were not exposed. Results are published online in the study entitled, â€śOrganophosphate Pesticide Exposure and Attention in Young Mexican-American Children,â€ť in the journal, Environmental Health and Perspectives.
Previous studies have shown that exposure to some organophosphate compounds cause hyperactivity and cognitive deficits in animals. One study published in Pediatrics earlier this year found that exposure to organophosphates in developing children might have effects on neural systems and could contribute to ADHD behaviors, such as inattention, hyperactivity, and impulsivity. Researchers discovered that for children with a 10-fold increase in the concentration of the most common phosphate metabolites measured in their urine, the odds of ADHD increases by more than half compared to those without detectable levels.
Roughly one in six children in the U.S. has one or more developmental disabilities, ranging from a learning disability to a serious behavioral or emotional disorder. Emerging science demonstrate that the amount of toxic chemicals in the environment that cause developmental and neurological damage are contributing to the rise of physical and mental effects being found in children. Organophosphates like chlorpyrifos, malathion and dichlorvos are extremely toxic to the nervous system. They are cholinesterase inhibitors and bind irreversibly to the active site of an enzyme essential for normal nerve impulse transmission -acetylcholine esterase (AchE), inactivating the enzyme. High concentrations of organophosphates have been found in the bodies of pregnant women and children.
In response to the growing evidence linking pesticide exposures to numerous human health effects, Beyond Pesticides launched the Pesticide-Induced Diseases Database, to capture the range of diseases linked to pesticides through epidemiologic studies. The database, which currently contains 383 entries of epidemiologic and laboratory exposure studies, will be continually updated to track the emerging findings and trends. To view the database, go to www.beyondpesticides.org/health.
For more information on childrenâ€™s exposure to pesticides, including information on how you can protect your family from pesticides and the latest studies and news on this topic, see Beyond Pesticides Children and Schools program page and the Organic program page.