Recently, two separate studies reported a correlation between exposure to pesticides and increased incidence of ADHD.
If you’re a parent and you hate bugs, you have a choice: you can either tough it out and live with the bugs, or you can spray the bugs with pesticides and spawn hyperactive kids — or at least that’s what new studies claim. Recently, two separate studies reported a correlation between exposure to pesticides and increased incidence of ADHD (attention deficit hyperactivity disorder) in children. The studies were published in Environmental Health Perspectives and Pediatrics, respectively.
Both studies focused on the impact of exposure to a type of pesticides called organophosphates, which are among the most commonly used of all pesticides. The research by American companies that led to the development of these pesticides was based on original research done by the Nazis in WWII to create nerve gases such as Sarin, Tabun, and Soman. Now, organophosphates form the basis for many pesticides and herbicides, and they’re also used as solvents and plasticizers. They work by irreversibly inactivating an enzyme called acetylcholinesterase, which is essential to nerve function in humans, insects, and animals. While organophosphates replaced an earlier class of compounds called organochlorides (including DDT) because they degrade more quickly, they have a far higher level of toxicity.
The study reported in Environmental Health Perspectives focused on the impact of in-utero exposure to organophosphate pesticides among more than 300 Mexican-American children in the agricultural Salinas Valley in California. The children were checked at age three-and-a-half, and then again at age five. Researchers measured the quantities of breakdown products from these pesticides in the mothers’ urine twice during pregnancy. Then they looked at the children to see if there was evidence of ADHD symptoms. They found that the children whose mothers had higher levels of pesticide products during pregnancy were much more likely to exhibit ADHD symptoms by age five, and this was especially true for boys.
According to study member Amy Marks, a research analyst at the University of California School of Public Health in Berkeley, “It is worth looking at this more carefully and conducting more research on this topic, since low-level exposure to pesticides and pesticide residues in food is quite common.”
But hasn’t the FDA repeatedly assured us that pesticide residue levels on our food are so low that they present no health hazard? What kind of data could possibly contradict the FDA?
The study published in Pediatricslooked at data from the general population of the U.S. It included 1139 children between the ages of eight and 15. Researchers found that the odds of developing ADHD more than doubled in children with a high level of a common breakdown product, dimethyl triophosphate, as compared to children with untraceable amounts in their urine. In general, a ten-fold increase in the quantity of any organophosphate compound increased the odds of the child developing ADHD by more than half.
According to study researcher Marc Weisskopf of the Harvard School of Public Health, even at low levels of exposure, “There is growing concern that these pesticides may be related to ADHD.” Dr. Weisskopf said that while the correlation of exposure to pesticides and the development of ADHD seemed clear, the mechanism that led to the development of the condition is not.
Not surprisingly, industry representatives played demure. Garry Hamlin of Dow AgroSciences, which manufactures an organophosphate called chlorpyrifos, said, “The results reported in the paper don’t establish any association specific to our product chlorpyrifos.” While the same Garry Hamlin confessed that he didn’t have time to read the study carefully, his response indicates that perhaps he doesn’t read much at all — either that, or he has a short, selective memory. Or perhaps he has ADHD, because in 2007, researchers from Columbia University published a study in Pediatrics that linked “exposure to chlorpyrifos to delays in learning rates, reduced physical coordination, and behavioral problems in children, especially attention deficit hyperactivity disorder.” And if that’s not enough, chlorpyrifos was outlawed for residential use in 2001, although is still used extensively in agriculture on corn, wheat, and soy. Can you say “Whoops.” Garry Hamlin?
Of course, pesticide residues do more than trigger hyperactivity. A study earlier this year, in fact, found a link between organophosphates and Alzheimer’s disease. And the most recent studies by the USDA found pesticide residues on over 70 percent of the fruits and vegetables tested. To reduce risk, researchers from both studies advise that you carefully and thoroughly wash fruits and vegetables before serving them. And Marc Weisskopf cautions parents to be aware of which pesticides they use around the house.
But why use pesticides around the house at all? Few insects are as dangerous, really, as the poisons used to kill them. Common sense would indicate that, if you are a parent or parent-to-be, your kids, your pets, and you are best served if you completely avoid using poisons or find non-toxic alternatives. And as for washing fruits and vegetables, do your best to buy organic or grow your own whenever possible (and still wash thoroughly with filtered water before serving). However, keep in mind that washing will not remove any pesticides trapped under any wax coating that was sprayed on the produce to prolong shelf life.