Dirty Dozen List Reveals Produce with Most Pesticide Residue

Every year the Environmental Working Group (EWG) updates its Dirty Dozen and Clean Fifteen lists in order to help shoppers know which fruits and vegetables are best to buy organic, and which ones are fine to buy non-organic. This year's list puts non-organic (also known as conventional) strawberries, spinach, and leafy greens – including kale, collard, and mustard greens – in the top three spots for most-contaminated produce, while avocados, sweet corn, and pineapple take the prize for cleanest produce.

The report reveals that over 90% of samples of conventional strawberries, apples, cherries, spinach, nectarines, and leafy greens tested positive for residues of two or more pesticides, and a single sample of kale, collard, and mustard greens had up to 20 different pesticides. Spinach was particularly bad, with 1.8 times on average as much pesticide residue by weight as any other crop tested. 

The Clean Fifteen list was clean indeed, with almost 70% of samples showing no pesticide residues whatsoever. A mere 8% of fruits and vegetables on the Clean Fifteen list had traces of two or more pesticides, whereas those on the Dirty Dozen often revealed multiple contaminants: "Hot peppers and bell peppers had the most pesticides detected, 115 pesticides in total and 21 more pesticides than the crops with the second highest amount – kale, collard and mustard greens."

The Dirty Dozen and Clean Fifteen lists are based on testing conducted by the U.S. Department of Agriculture (USDA) and Food and Drug Administration (FDA), which takes annual samples from over 46,000 crops. The EWG Shopper's Guide ranks 46 of those samples in order from cleanest to dirtiest, using data from the most recent one-to-two-year sampling period for each food.

While an all-organic diet may be ideal, it is not a prerequisite for healthy eating. These lists are meant to help shoppers at all budgetary levels. If you can afford to spend money on some organic products, the items on the Dirty Dozen list are the best ones to target, while the Clean Fifteen are fine to consume when grown conventionally. The most important thing, though, is just to keep eating plenty of fruits and vegetables:

"When organic versions are unavailable or not affordable, EWG advises consumers to continue eating fresh produce, even if conventionally grown."

EWG's Dirty Dozen for 2021

Prioritize buying these organic if and when you can.

1. Strawberries
2. Spinach
3. Kale, collard, and mustard greens
4. Nectarines
5. Apples
6. Grapes
7. Cherries
8. Peaches
9. Pears
10. Bell and hot peppers
11. Tomatoes
12. Celery

EWG's Clean Fifteen for 2021

These choices have the least amount of pesticide and buying organic is less important.

1. Avocados
2. Sweet corn
3. Pineapple
4. Onions
5. Papaya
6. Sweet peas (frozen)
7. Eggplant
8. Asparagus
9. Broccoli
10. Cabbage
11. Kiwi
12. Cauliflower
13. Mushrooms
14. Honeydew melon
15. Cantaloupes

This year's report highlights the prevalence of fungicides on non-organic citrus fruits. These fungicides are linked to hormone disruption and cancer. Alexis Temkin, Ph.D., EWG toxicologist, told Treehugger that the organization is shining a spotlight on fungicides because of their potential harm to children's health and how often they're detected.

"The fungicide imazalil is classified by the Environmental Protection Agency (EPA) as a likely human carcinogen. It can harm the endocrine system and is also found on nearly 90% of citrus samples tested by EWG and 95% of tangerines tested by USDA in 2019. Fungicide use also seems to be increasing over time, with more than 70% of samples tested by EWG containing both imazalil and thiabendazole."

While the researchers anticipated that fungicides would be prevalent, based on previous USDA test results, Temkin said that they were "surprised to see average levels more than 20 times the level EWG scientists recommend to protect children from increased cancer risk."

The citrus, like all other fruits and vegetables tested by the EWG, were washed and peeled before testing, in order to best imitate how people would eat them at home.

This was the first time testing bell peppers and hot peppers in a decade, and both showed concerning levels of acephate and chlorpyrifos, respectively. The report explains that these are "organophosphate insecticides that can harm children’s developing brains and are banned from use on some crops in the U.S. and from all uses in the EU." The EPA rejected a proposed chlorpyrifos ban in 2017, which allowed it to remain on the market and subsequently in the foods we buy.

EWG is concerned about the effect of pesticides on children's health and the fact that, despite the landmark 1996 Food Quality Protection Act requiring the EPA to protect children's health by applying an extra margin of safety to legal limits for pesticides in food, these have not been enacted. From the report: "As our investigation found, this tenfold margin of safety was not included in the EPA’s allowable limits for almost 90% of the most common pesticides."

The report also mentions a study published this year in the peer-reviewed journal Nutrients, in which researchers at Harvard University ranked fruits and vegetables according to their pesticide levels, based on USDA testing data, and then measured the urinary pesticide concentrations of people who ate them. It shows that "eating organic food reduces pesticide exposure and is linked to a variety of health benefits."