When kids eat conventionally grown fruits and vegetables, what level of pesticide residues are they taking in — and to what effect?

The answers to those questions remain murky, because little research has been done. But evidence is building that the way we think about pesticide risk, especially in children, is all wrong. A few years ago, scientists at Emory and the University of Washington showed that when children switched to organic fruits and vegetables, pesticide residue in their bodies (as measured in their urine) dropped significantly within days. But what wasn’t clear at the time was the pesticide load in a typical kid’s diet, since the scientists in the organic study had themselves established the diet given to the kids.

Now, Chensheng Lu, the lead scientist involved with the earlier study, has come out with a new one, along with a team of government and university researchers. This time, he and his team analyzed the pesticide residue on the fresh fruits and vegetables that parents gave their kids. The researchers analyzed the fruit-and-veg consumption of two groups of kids, one from Washington state and one from Georgia.

They found, as expected, a witch’s brew of organophosphatf and pyrethroid pesticides — both of which are endocrine disruptors and have suspected neurological effects — on the fresh fruit and vegetables the study participants ate. Organophosphates, by the way, are the direct descendants of VX and Sarin nerve gases and were recently linked to the development of ADHD in kids.

Now, the individual pesticides were present at levels more or less consistent with what the government considers “safe” (with a few notable exceptions).  But that’s far from the whole story. The researchers clearly demonstrated that seasonality plays a huge role in kids exposure to pesticides in these classes. In other words, in apple season kids eat a lot of apples — and, along with them, much higher levels of organophosphates than previously estimated. As obvious as this conclusion is, it’s not really one that is acknowledged in current government estimates.