The sad news is that neurologist have known that pesticides are harmful to cognitive function for a long time. They have seen children exposed to pesticides on farms suffer cognitively as a result of organophosphate exposure and have warned against having young children close to fields during fumigation.
What they did not know is that even very small levels of exposure are harmful. The Environmental Protection Agency (EPA) limits how much residual pesticide can be left on food but this allowed amount, as it turns out, is harmful. In a way this is very similar to the lead story. The EPA set limits on the lead exposure that was considered 'safe' and but the allowed exposure level can actually cause cognitive problems and ADHD.
Studies on what foods contain the most residual pesticides have found that the Peaches, Apples, Sweet Bell Peppers, Celery, Nectarines, Strawberries, raspberries, Cherries, Pears, Grapes (Imported), Spinach, Lettuce, and potatoes contain the most organophosphates and that even frozen strawberries and blueberries have been found to have dangerous levels of pesticides. Washing the fruit does nothing to get rid of the pesticides as they penetrate the skin and reside in the part of the fruit that we eat. Even thick skin fruit like oranges contain pesticides.
The best way to avoid exposure is to eat organic fruits and vegetables or to avoid the above fruits and vegetables altogether. Most of us cannot afford all organic fruits and vegetables so I have a list of the fruits and vegetables with the least level of pesticides. They include: onions, avacado, frozen corn, pineapples, mango, asparagus, frozen peas, kiwi, bananas, watermelon, cabbage, broccoli, and papaya.
You can eliminate 80% or your exposure by avoiding the foods on the high pesticide list and choosing the low pesticide food instead. Pet products can also contain toxic pesticides so avoid pet shampoo, flea collars and other flea medicines with organophosphates and avoid using toxic pesticides in the home and garden.