The Environmental Working Group has released its 2019 Dirty Dozen and Clean Fifteen lists as part of its new Shopper’s Guide to Pesticides in Produce. Kale features on the list of "dirty," pesticide-contaminated produce for the first time in a decade.
Researchers found that more than 92 percent of conventionally grown kale samples had at least two or more pesticide residues; almost 60 percent tested positive for DCPA, which the EPA has classified as a possible human carcinogen and has been prohibited for use on crops in the E.U. since 2009.
“We were surprised kale had so many pesticides on it, but the test results were unequivocal,” EWG Toxicologist Alexis Temkin, Ph.D, says in a press release.
Kale has not been tested for pesticides by the USDA since 2009, when it ranked in eighth place on the Dirty Dozen list. Given the popularity of the vegetable, American kale-growing acreage has increased by more than 56 percent between 2007 and 2012. This, Temkin notes, could be part of the reason for its high-ranking position on the list.
“We have seen an increase in the amount of kale being grown and that could have some impact on pesticide residue detections,” she tells Organic Authority, noting that it could also be due to changes in pesticide use practice and analytical methods for monitoring residues.
“The fact is, since the USDA has not tested kale in nearly a decade, some of this intermediate information is missing, and that’s a problem,” she says.
The Dirty Dozen and Clean Fifteen lists, which the EWG has been releasing every year since 2004, identify the foods on the U.S. market most likely to carry pesticide residues. EWG compiles the lists based on USDA test data of more than 40,900 produce samples.
This year, strawberries top the list of dirtiest produce for the fourth time in a row. Almost all samples (99 percent) had detectable pesticide residues, including known endocrine disruptor Carbendazim.
In second place comes spinach, followed by kale. Nectarines, apples, grapes, peaches, cherries, pears, tomatoes, celery, and potatoes round out the Dirty Dozen. To avoid pesticides, consumers should opt for organic versions of these items whenever possible.
While Temkin notes that “there is some evidence that organic samples can be contaminated through drift, especially for high volume pesticides like glyphosate,” she also notes that “the carry-over levels of pesticide residues on organic produce are low and switching to an organic diet drastically reduces the levels of pesticides measure in human urine samples.”
Avocado ranked as the cleanest item, followed by sweet corn, pineapple, frozen peas, and onions. Papaya, eggplant, asparagus, kiwi, cabbage, cauliflower, cantaloupe, broccoli, mushrooms, and honeydew were also ranked least contaminated.
EWG notes, however, that a small amount of sweet corn and papaya is produced from GMO seeds in the U.S., so consumers hoping to avoid GMOs should opt for organic varieties of these products, despite the relative cleanliness of conventional versions.
Produce was washed and peeled produce before testing, just as one would at home. This, EWG stresses, “shows that simple washing does not remove all pesticides.”
“The main route of pesticide exposure for most Americans who do not live or work on or near farms is through their diet,” said EWG Research Analyst Carla Burns. “Studies have shown that eating fruits and vegetables free of pesticides benefits health, and this is especially important for pregnant women and children.”
Nearly 70 percent of the produce sold in the U.S. has pesticide residues, according to EWG’s analysis. One French study published in JAMA Internal Medicine found that people with the highest frequency of organic food consumption had 25 percent fewer cancers than individuals who did not eat organic food.
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