Pesticides have been linked to cancer, reproductive harm, hormone disruption and neurotoxicity in children. Residues of these chemicals are often detected on produce, creating exposure concerns for consumers. The new study may help inform future research into how dietary exposure to pesticides through fruit and vegetables might affect human health.
“The findings reinforce that what we eat directly affects the level of pesticides in our bodies,” said Alexis Temkin, Ph.D., vice president for science at EWG and lead author of the study. “Eating produce is essential to a healthy diet, but it can also increase exposure to pesticides.”
Participants who consumed more fruits and vegetables with higher levels of pesticide residues – like strawberries, spinach and bell peppers – had significantly higher levels of pesticides in their urine compared to those who ate mostly produce with lower levels of pesticide residue. These findings highlight how diet is a driver of pesticide exposure and provide a foundation for future research into how that exposure might affect human health over time.
“This study builds on previous work showing that certain fruits and vegetables are a major route of pesticide exposure for millions of Americans,” said Temkin. “Young children and pregnant people are particularly susceptible to the harms from exposure.”
Scoring pesticide exposures
The study was published in the International Journal of Hygiene and Environmental Health.
EWG scientists first collected Department of Agriculture data on pesticide residues in produce from 2013-2018. They combined this with dietary questionnaire responses and urine biomonitoring information from 1,837 participants in the Centers for Disease Control and Prevention’s National Health and Nutrition Examination Survey, or NHANES, from 2015 to 2016. These years reflect the most current data with the broadest range of pesticide tracking. NHANES biomonitoring results are only available through 2018.
Using this data, EWG created a “dietary pesticide exposure score” to estimate people’s exposure based on the fruits and vegetables they ate, and pesticide levels on that produce. Pesticide amounts on produce were determined by how often and how much of each chemical was detected. EWG also factored in the concentration and toxicity of each pesticide.
Scientists then compared the exposure scores to 15 pesticide biomarkers, or indicators, in participant’s urine for three major classes: organophosphates, pyrethroids and neonicotinoids.
The results revealed a clear link between the specific produce people consumed and the levels of these pesticides that were detected in their urine, varying based on what they ate and the pesticides on those fruits and vegetables.
Key findings
Beyond highlighting the link between eating certain produce and increased levels of pesticides in people’s bodies, EWG’s study includes a number of important findings.
Diet matters. Eating produce with high pesticide residues is more strongly associated with the chemicals being found in urine compared to low-residue items. Certain pesticide classes need more attention: NHANES currently monitors only a subset of pesticides found in food and identified in the study. Many more pesticides need attention because people are exposed to a wide range of agricultural chemicals. People are exposed to mixtures of pesticides: The study confirms people are exposed to several pesticides at a time. Fruits and vegetables had measurable residues of 178 unique pesticides, but only 42 of those chemicals matched biomarkers in the urine data. Potatoes skew the results. The relationship between produce consumption and pesticide levels in the body was only evident when potatoes were excluded from the analysis. Potato consumption obscured the study’s findings, possibly because people eat potatoes in a variety of ways, which makes it more difficult to accurately estimate pesticide exposure from them. More research is needed into how potatoes influence pesticide exposure in people.
Regulatory gaps
While most pesticide research has focused on occupational and residential exposures, EWG’s study shows that everyday food choices can also drive significant pesticide exposure in the general population.
Given the widespread exposure documented in this paper and other studies, serious questions remain about whether current pesticide safety regulations set by the Environmental Protection Agency sufficiently protect public health.
Despite years of research linking low-level pesticide exposure to health risks, the EPA still sets limits for individual pesticides, failing to account for cumulative exposure from mixtures of residues regularly detected on produce samples tested by the USDA.
The study’s authors suggest that their methodology for estimating pesticide exposure from fruits and vegetables could give regulators and other researchers a powerful tool to assess real-world exposures and better safeguard vulnerable populations, particularly children and people who are pregnant.
"This study was only possible thanks to robust federal data, highlighting why strong public health agencies must remain a top priority for policymakers,” said Varun Subramaniam, EWG science analyst.
“The pesticide residue tests and CDC biomonitoring data represent the kind of essential research that only the government can provide – at a scale that no private sector or academic effort could match,” he said.
What consumers can do
EWG urges people to eat plenty of fruits and vegetables, whether grown conventionally or organic.
Switching from conventional produce to organic, which cannot be grown using certain pesticides, has been shown to dramatically reduce pesticide biomarkers in the body within days.
When possible, EWG recommends prioritizing organic purchases for the most contaminated items listed in its Shopper’s Guide to Pesticides in Produce™. The guide features the “Dirty Dozen™” list of the produce with the highest pesticide residues detected and the “Clean Fifteen™” list of items with the lowest residues.
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The Environmental Working Group (EWG) is a nonprofit, non-partisan organization that empowers people to live healthier lives in a healthier environment. Through research, advocacy and unique education tools, EWG drives consumer choice and civic action.
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