Affordable, simple household practices can reduce pesticide levels on fruits and vegetables and help consumers lower their daily dietary exposure to potentially harmful farm chemicals, a new study by Environmental Working Group, or EWG, scientists finds.
The study offers helpful information to be used in addition to EWG’s pesticide consumer guidance in the annual Shopper’s Guide to Pesticides in Produce.
“Fruits and vegetables are essential to a healthy diet, but they can also increase exposure to pesticides,” Dayna de Montagnac, M.P.H., associate scientist at EWG and lead author of the study, said in a statement.
“Our findings reinforce the effectiveness of safe and accessible ways to reduce pesticide exposure while highlighting necessary improvements in research and monitoring to further reduce it,” de Montagnac said.
Pesticide residues on produce
The review, published recently in the journal Frontiers in Environmental Health, analyzed data from 47 peer-reviewed studies of 23 produce items and 79 pesticides.
EWG scientists reviewed data that recorded pesticide concentrations of fruits and vegetables before and after rinsing or soaking them with water, baking soda, or vinegar. Experiments where scientists rinsed their produce for more than two minutes were excluded to better reflect how people likely wash their produce at home.
Among the key findings:
- All washing methods reduced pesticide residues, but effectiveness varied widely.
- Rinsing with water showed modest reductions, with a median of 30.2 percent, although reductions ranged from 0 percent to 94 percent.
- Soaking in plain water performed slightly better than rinsing, with reductions from 0.6 percent to over 99 percent and a median of 33.7 percent.
- Baking soda soaking substantially improved removal, achieving reductions from 0.2 percent to more than 99 percent, with a median of 50.9 percent.
- Vinegar, or acetic acid, soaking was the most effective method overall, with reductions ranging from 8.6 percent to more than 99 percent and a median of 54.2 percent.
- Baking soda and vinegar treatments outperformed plain water by more than 15 percentage points in median pesticide reduction across studies, likely because of how certain pesticides break down in alkaline or acidic environments.
- Real-world effectiveness may be lower than what EWG’s study showed, since many studies used higher concentrations of baking soda or vinegar than a typical household would.
- Key factors influencing pesticide removal included the chemical properties of the pesticide, the washing method used, and the type and surface characteristics of the produce.
These findings confirm the role washing produce can provide in moderately lowering pesticide levels, she said.
What consumers can do
The EWG recommends regularly washing and eating plenty of fruit and vegetables.
Washing produce in any way will always be better than no washing in reducing exposure to pesticide residues, according to the EWG. The USDA’s Pesticide Residue Program rinses produce samples with cold water for 15 to 20 seconds before testing produce, reflecting the assumption that consumers do basic washing at home.
A quick rinse or soak works in a pinch, de Montagnac said. When feasible, the addition of baking soda or vinegar to soaking solutions can further reduce residues. See EWG’s guide on washing produce for details.
The EWG recommends prioritizing organic produce for the most pesticide-heavy produce listed in its Shopper’s Guide. 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.
Why it’s important to remove pesticides from produce
Last year, the EWG published research showing how the consumption of fruits and vegetables with higher pesticide residues is linked to measurable levels of pesticides in urine. Other recent publications have investigated the growing problem of PFAS pesticides, chlormequat, and glyphosate in the food supply.
Studies of the general population show exposure to pesticides is linked to cancer, reproductive harm, hormone disruption, and neurotoxicity in children.
Residues of these chemicals are often detected on produce and frequently appear in mixtures on every type of produce, except potatoes, with an average of four or more pesticides detected on individual samples, according to EWG’s recent analysis of U.S. Department of Agriculture pesticide testing data.
Where more work is needed
The study’s authors recommend that government agencies make it a priority to monitor stubborn pesticides, those that remain on produce even after household washing.
They also suggest expanding biomonitoring, measuring the amount of a chemical, of fruits and vegetables to include pesticides frequently detected in the U.S. food supply.
Future research should explore what proportion of pesticide residues remain in specific produce items and how much these residues increase exposure.
