There is no direct scientific or medical evidence indicating that typical exposure of consumers to pesticide residues poses any health risk, according to a new report from the Council for Agricultural Science and Technology (CAST). Pesticide residue data and exposure estimates typically demonstrate that food consumers are exposed to levels of pesticide residues that are several orders of magnitude below those of potential health concern.
Consumers are concerned about their exposure to pesticides through fruits and vegetables bought at the grocery store, but that fear is not supported by scientific evidence, CAST said. The report aims to reduce consumers’ worries by describing how information from complex risk assessments can be misinterpreted in news stories and by consumer advocacy groups. The innately complex findings from scientific publications can easily be shaped into unfavorable narratives that end up confusing grocery buyers more than aiding them.
“Consumers should feel confident, rather than uncomfortable, when purchasing fruits and vegetables,” says Dr. Carl K. Winter, Cooperative Extension Food Toxicology Specialist Emeritus at the University of California, Davis, and chair author of the CAST publication.
The new CAST paper provides an overview of how pesticides are used in crop production and their benefits in the food production system. The authors also offer accurate evaluations of scientific sources commonly used by media outlets and advocacy groups to shape consumer advice.
The U.S. Food and Drug Administration, the primary federal agency responsible for enforcing pesticide tolerances, found that a majority of samples contained no detectable pesticide residues while most of the detectable residues were within tolerance levels. Pesticide residue violations can occur when residue levels exceed the tolerance established for the specific pesticide/food combination, and when residue levels—at any level—are detected on foods for which a tolerance is not established.
The FDA found that a majority of samples from both domestic and imported foods contained no detectable pesticide residues while most of the detectable residues were within tolerance levels. A large difference in violation rates was seen with domestic samples showing a 0.9% violation rate while import sample violations were much higher (9.8%).
The presence or absence of pesticide residues is not a valid indicator of health risk to the consumer. “Pesticides, like all chemicals, obey the first principle of toxicology: ‘The dose makes the poison.’ Thus, it is the amount of exposure and not the presence or absence of a chemical that determines the potential for harm,” the report explains.
Results of six epidemiological studies examining the relationship between exposure to the insecticide chlorpyrifos and childhood intelligence are discussed. Chlorpyrifos has been a common targeted pesticide and California has even taken steps to phase out its use by 2020. Two of the six studies indicated a positive correlation between chlorpyrifos exposure and reduced childhood intelligence but both focused on exposure from non-food sources (indoor pesticide use and agricultural pesticide use). Another study looking at indoor chlorpyrifos use did not identify any correlation to childhood intelligence nor did three other epidemiological studies estimating chlorpyrifos food exposure.
For example, results from U.S. federal regulatory monitoring programs are common sources used by advocacy groups to provide advice to consumers, such as what fruits and vegetables are most likely to contain pesticide residues. However, their guidance is in contrast to the actual findings from these federal programs, which often find most foods do not contain detectable amounts of pesticides. The foods that do have traceable amounts contain so little, they are considered harmless to human health.
Researchers have demonstrated that such advice lacks scientific justification and may result in some consumers reducing their consumption of fruits and vegetables, a practice strongly associated with adverse health effects.
“Recommendations made by advocacy groups that consumers avoid specific fruits and vegetables are not backed up with sound science,” Winter says. “The worst thing consumers can do is to reduce their consumption of healthy fruits and vegetables—organic or conventional—due to unwarranted concerns regarding pesticide residues.”
The uses and benefits of pesticides in food production should also be recognized, the report notes. “Pesticides provide one tool to produce a safe, effective, and economically viable food supply, particularly when they are used in concert with a variety of other biological, genetic, cultural, and mechanical approaches to control pests. Pesticides can improve land- and water use efficiencies that can minimize energy requirements and reduce greenhouse gas emissions. In addition, pesticides provide a powerful tool in reducing food waste as well as in increasing food safety,” the report states.