Most of our ten participants don’t spray these insecticides in their home or garden, so the most likely source of the pesticides in their bodies is their food, especially since most of their diets are not organic. The organophosphate pesticides diazinon and chlorpyrifos, once the most widely used insecticides in U.S. homes and gardens, are now primarily used in agriculture (with a few exceptions, they are not used in urban areas). Azinphos methyl is highly acutely toxic and is used only in agriculture, on such crops as apples, cherries, and pears (USEPA 1999). Malathion is used in both settings, but most commonly in agriculture. Carbaryl is sprayed on about half of Washington’s apple crop and much of its grape acreage (WSDA 2003).

The U.S. Department of Agriculture (USDA) conducts a yearly “market basket” survey to test for residues of pesticides in produce. The most-contaminated fruits and vegetables include apples, bell peppers, celery, cherries, grapes, nectarines, peaches, pears, potatoes, raspberries, spinach, and strawberries. Purchasing some foods in particular comes with a near-guarantee of pesticides along for the ride. USDA’s most recent testing found that 98% of apples and 97% of bell peppers are contaminated (USDA 2006). All of the apples and pears tested by the USDA were contaminated with 1-napthol, the breakdown product of carbaryl. The agency found up to nine pesticides on a single apple and eight in a single grape sample.

We found evidence in our study that suggests eating organic provides some protection from pesticide exposure. We tested for a correlation between pesticide detections in our participants and the number of organic meals each person reported eating. We found a statistically significant correlation, indicating that the more organic food each participant ate, the less likely he or she was to have pesticides in his or her body.⁶

Farm workers and farm worker families are exposed to the most agricultural pesticides by far. While mixing and applying pesticides, they come into contact with significant amounts of chemicals, later tracking them into their homes on their shoes and clothing. Their homes, which are often near the farms they work on, become further contaminated when pesticides drift from nearby fields.