Spinach is packed with nutrients, making it a staple for healthy eating during the winter and spring. But federal data shows that conventionally grown spinach has more pesticide residues by weight than all other produce tested, with three-fourths of samples tested contaminated with a neurotoxic bug killer that is banned from use on food crops in Europe.
The latest tests by the Department of Agriculture in 2015 and 2016 showed a sharp increase in pesticide residues on non-organic spinach since the crop was last tested in 2008 and 2009. Based on the USDA tests, EWG’s Shopper’s Guide to Pesticides in Produce™ ranks spinach second on the Dirty Dozen™ list of fruits and vegetables with the most pesticides – a significant jump from its previous rank of eighth.
The USDA recently published results of a pesticide analysis for 642 conventionally grown spinach samples collected in 2016. These samples contained far more pesticides by weight than all other crops tested, and double or more than the amount found on all other Dirty Dozen crops.
The tests detected an average of 7.1 pesticides on every conventionally grown spinach sample collected in 2016, with a maximum of 18 different pesticides or breakdown products on a single sample. Four pesticides – one insecticide and three fungicides – were responsible for the bulk of the residues detected on spinach.
Seventy-six percent of the samples contained residues of permethrin, a neurotoxic insecticide. At high doses, permethrin overwhelms the nervous system and causes tremors and seizures.
But several studies also find a link between lower-level exposure to permethrin-type insecticides and neurological effects in children. In one study, children with detectable permethrin residues in their urine were twice as likely to be diagnosed with ADHD as children with non-detectable levels of the pesticide.
Besides its use as a pesticide, permethrin is also used to kill head lice and is embedded in mosquito-repellent fabrics. The Environmental Protection Agency is currently assessing the health risks of permethrin and related pesticides on food. EWG wrote to the EPA urging it to consider potential risks to children’s brain development. Since 2000, Europe has not permitted any permethrin to be used on food crops.1
Three other previously undetected fungicides – mandipropam, fluopicolide and ametoctradin, which are used to kill mold and mildew – were found at relatively high concentrations on spinach samples. These were not found in earlier in spinach tests and are relatively uncommon on other produce.
Most of the pesticides found on conventional spinach samples are sanctioned as legal and safe by the EPA. In 2016, 16 of 707 samples had concentrations that violated the EPA’s maximum pesticide residue limits. The USDA found 83 samples that had residues of pesticides that are prohibited for use on spinach, but are legal on other food crops. Nearly all of these were grown in the United States.
DDT, a pesticide long banned in the U.S., also showed up on spinach and very few other crops. Residues of DDT and its breakdown products were found on 40 percent of spinach samples.
DDT breakdown products were detected in much lower concentrations than the other spinach pesticides, but are far more toxic to people. Although DDT was banned in the 1970s, residues remain in the soil and are picked up by spinach grown today.
Spinach sold in U.S. grocery stores is mostly grown domestically, with 60 percent coming from California. Arizona, New Jersey and Texas, and foreign imports making up the rest.
- Eat lots of vegetables and fruits. Spinach is a great source of vitamin A, folate and vitamin C. It’s also a good source of vitamin E and potassium.
- Buy organic spinach and other leafy greens if you can. The USDA hasn’t tested pesticide levels on kale and collard greens since 2008, but some highly toxic pesticides can still be used legally on leafy greens like kale and collard greens.
- Wash spinach thoroughly. California tests of unwashed spinach found higher concentrations of pesticides. The USDA washed all of the spinach samples vigorously before testing. The USDA has also detected pesticides on frozen and canned spinach, suggesting that washing and cooking reduces pesticide levels but does not eliminate them.
- European Commission, Permethrin. Directorate General for Agriculture, 2000; 6522/VI/99-Final, DG VI-B.II-1 13. Available at ec.europa.eu/food/plant/pesticides/eu-pesticides-database/public/?event=activesubstance.ViewReview&id=55
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