(Beyond Pesticides, Aug 16, 2010)
A recently released study conducted by the National Institutes of Environmental Health Sciences shows government agencies may be underestimating children’s dietary exposure to pesticides and, therefore, the inherent risks to children’s health. The study, “Assessing Children’s Dietary Pesticide Exposure- Direct measurement of Pesticide Residues in 24-Hour Duplicate Food Samples” lead by Dr. Chensheng Lu, examines the pesticide residues in foods consumed by children in a study group and builds on a previous study published in 2008 entitled “Dietary Intake and Its Contribution to Logitudinal Organophosphorus Pesticide Exposure in Urban/Suburban Children.”
The 2008 study examined the concentrations of organophosphate pesticides in the bodies of children who consumed a diet of conventional produce and then switched to a diet of organic produce. The study examined two groups of 23 children ranging in age from 3 to 11, in Seattle, Washington and Atlanta, Georgia. Researchers measured the concentrations of malathion, chlorpyrifos, and other organophosphate pesticide metabolites in the children’s urine. These pesticides have no residential uses, and because all children in the study group live in urban or suburban areas, researchers assumed that all exposure to these pesticides were the result of diet. The children were then fed a strictly organic diet for five days. After the five day period, researchers found that concentrations of malathion and chlorpyrifos metabolites in the children’s urine were reduced to non-detectable or close to non-detectable levels. What this study did not establish was how much pesticide residue the children actually consumed from the diet of conventional produce.
This new study, on the other hand, uses the same group of children to examine the amount of pesticides children take in when eating conventional produce. To determine the precise amount of pesticide residue consumed, parents collected duplicate food samples of all fruits, vegetables, and juices equal to the quantity consumed by their children over a 24-hour period. Parents were instructed to wash and prepare the duplicate samples in the same way as the food their children consumed. This process was repeated at different times during the year to account for seasonal differences in diet.
Researchers also conducted a market basket analysis, testing the residue on fruits and vegetables purchased from a supermarket in the same neighborhood as children in the Seattle study group (a market based analysis was not conducted in Atlanta due to lack of resources). Samples were analyzed for residues of organophosphosphours and pyrethroid pesticides. When possible, residue results were then compared with the residues reported by the United States Department of Agriculture Pesticide Data Program (PDP). However, because many of the foods consumed by children in the study group have not been tested by the PDP, researchers were not always able to compare residue results. Researchers found pesticide residues in 19% of the duplicate food samples; 23% of the Seattle samples and 15% of the Atlanta samples contained either an organophosphorus or pyrethroid insecticide. The most commonly consumed foods included apples, apple juice, bananas, carrots, orange juice, peaches, and watermelon. In the market basket analysis, 28% of samples contained either an organophosphorus or pyrethroid pesticide. With a few exceptions researchers found residues to be within the range reported by the PDP.
Researchers also noted that consumption of certain foods varies greatly if those foods are seasonal. Currently, seasonal differences in the consumption of fresh produce are not taken into account by the Centers for Disease Control (CDC) or the Food and Drug Administration (FDA) when creating mathematical models to estimate pesticide dietary exposure and risk. As a result, these models may greatly underestimate pesticide exposure from these foods. For example the consumption of peaches increases greatly when it is in season. Because peaches are considered by Environmental Working Group to be a member of the Dirty Dozen, the twelve types of fruits and vegetables contaminated with the most pesticide residue, models that look at the annual average peach consumption may assume that children consume an average of one or less servings a week, and would therefore estimate the risk posed by peach consumption to be acceptable. When peaches are in season, children might consume one or more servings a day, meaning the risk to their health is much higher than the model implies. Moreover, many types of fresh produce are in season around the same time of year, meaning that children may be getting a much higher pesticide load from their diet over a short span of time. This study is especially important as research continues to strengthen the link between pesticide exposure in children and diseases such as Attention Deficit Hyperactivity Disorder (ADHD).
Dietary pesticide exposure can be effectively eliminated by choosing organic foods. Beyond Pesticides supports organic agriculture not only for the benefits to human health, but also as effecting good land stewardship and a reduction in hazardous chemical exposures for workers on the farm. The pesticide reform movement, citing pesticide problems associated with chemical agriculture, from groundwater contamination and runoff to drift, views organic as the solution to a serious public health and environmental threat. For more information on the importance of choosing organic see our Eating with a Conscience page.