Finding Healthier Food
People don’t like pesticides on the food they eat or in the water they drink. The most recent government pesticide tests establish the widespread presence of pesticide residues on conventionally grown fruits and vegetables and in tap water. Even more disconcertingly, government scientists also tested three popular types of baby food and found pears and green bean samples contaminated with fungicides and bug killers.
In government tests analyzed by the Environmental Working Group, 68 percent of food samples had detectable pesticide residues after they had been washed or peeled. We found striking differences between the number of pesticides and amount of pesticide detected on Dirty Dozen Plus™ and Clean Fifteen™ foods.
The Dirty Dozen Plus™
For the past eight years, EWG has scrutinized pesticide testing data generated by scientists at the U.S. Department of Agriculture and federal Food and Drug Administration and has created its signature Dirty Dozen™ list of foods most commonly contaminated with pesticides. As well, we publish our Clean Fifteen™ list of the foods least likely to be pesticide-tainted. This year we have expanded the Dirty Dozen™ with a Plus category to highlight two crops -- green beans and leafy greens, meaning, kale and collard greens – that did not meet traditional Dirty Dozen™ criteria but were commonly contaminated with highly toxic organophosphate insecticides. These insecticides are toxic to the nervous system and have been largely removed from agriculture over the past decade. But they are not banned and still show up on some food crops.
Highlights of this year's Dirty Dozen™
- The most contaminated fruits, in alphabetical order, are apples, domestic blueberries, grapes, imported nectarines, peaches and strawberries.
- The most contaminated vegetables are bell peppers, celery, cucumbers, lettuce, potatoes and spinach.
- Every sample of imported nectarines tested positive for pesticides, followed by apples (98 percent) and imported plums (96 percent).
- The average imported nectarine had much higher total weight of pesticides than any other food crop.
- Grapes had 15 pesticides detected on a single sample. Blueberries and strawberries both had 13 different pesticides detected on a single sample
- As a category, grapes have more types of pesticides than any other produce, with 64 different pesticides.
- Some 96 percent of celery samples tested positive for pesticides, followed by potatoes (91 percent).
- A single bell pepper sample was contaminated with 15 different pesticides, followed by a single sample of celery with 13.
- Bell peppers had 88 different pesticide residues, followed by cucumbers (81) and lettuce (78).
Plus
Organophosphate insecticides, which are neurotoxic, were detected mainly on four foods: bell peppers and nectarines, which are on the Dirty Dozen™ because they show residues for many pesticides, and also green beans and leafy greens, defined as kale and collards. The latter two crops did not make the Dirty Dozen™ this year but showed potentially unhealthy levels of organophosphates residues. For this reason, we have added them to the list of foods to avoid, or to buy organic.
Over the past decade organophosphates have largely been withdrawn from use. Yet they can be applied to certain crops. The federal Environmental Protection Agency and the agricultural industry claim that associated toxicity risks are now under control. However a study led by Stephen Rauch of British Columbia's Children's Hospital and published earlier this year in the scientific journal Environmental Health Perspectives found decreases in baby birth weight and shorter pregnancy in 300 Ohio mothers who showed elevated organophosphate exposures during pregnancy. These pregnancies took place after organophosphates were restricted for most uses (Rauch 2012). The Rauch study indicates that organophosphate exposures must be further curtailed to protect children’s health.
To investigate ongoing use of organophosphates, measured as residues on recent USDA food samples, we created a risk index that combines the average residue levels and EPA’s chronic reference dose. This metric determined that the organophosphates acephate, methamidiphos, chlorpyrifos, diazinon, and azinphos-methyl posed the greatest dietary risks.
Pesticides in Baby Food
This year the USDA took its first look at pesticide residues on baby food. It tested about 190 samples each of green beans, pears and sweet potatoes prepared and marketed as baby food. All the samples dated from 2010.
Green beans prepared as baby food tested positive for five pesticides, among them, the organophosphate methamidiphos, which was found on 9.4 percent of samples and the organophosphate acephate, on 7.8 percent of samples. Based on our calculations, a 22-pound child eating one four-ounce serving of green beans sold as baby food with the maximum methamidiphos level found would consume 50 percent of EPA’s acute risk value, a measure of allowable risk. The risks would be higher if the beans were contaminated with a second organophosphate, acephate, which causes the same damages to the brain and nervous system. Lighter babies, those fed more than four ounces of green beans or those fed green beans with organophosphate residues daily would be at still greater risk.
EWG analyzed baby food samples in 1995 and found the two organophosphates in surprisingly similar concentrations.
Pears prepared as baby food showed significant and widespread contamination. Fully 92 percent of the pear samples tested positive for at least one pesticide residue. Some 26 percent of the samples were tainted with 5 or more pesticides. Disturbingly, the pesticide iprodione, which EPA has categorized as a probable human carcinogen, was detected on three baby food pear samples. Iprodione is not registered with EPA for use on pears. Its presence on this popular baby food constitutes a violation of FDA regulations and the federal Food, Drug, and Cosmetic Act.
The one bright spot was sweet potatoes sold as baby food, which had virtually no detectable pesticide residues.
The extent of pesticide contamination documented by USDA’s baby food tests highlights the need for the department to accelerate testing of baby foods and for EPA to reduce further the organophosphate pesticides exposures allowed for Americans, especially infants.
Drinking water
In 2010 USDA analyzed samples from 12 community drinking water systems that use surface water such as reservoirs, lakes and rivers as their water sources. Tests of 284 samples taken after treatment detected 65 pesticides or their metabolites. The toxic herbicide atrazine or its metabolites were found in every single sample. The herbicides 2,4-D and metolachlor were detected in more than 70 percent of the samples. Six other pesticides were found in at least half the samples.
The Clean Fifteen™
The Clean Fifteen™ – the produce least likely to test positive for pesticide residues were these fruits -- domestic cantaloupe, grapefruit, kiwi, mango, pineapple and watermelon -- and these vegetables -- asparagus, avocado, cabbage, eggplants, mushrooms, onions, frozen peas, sweet corn and sweet potatoes.
Notable findings:
- Fewer than 10 percent of pineapple samples had detectable pesticides.
- Some 78 percent of mango, 75 percent of kiwi, 67 percent of watermelon and 60 percent of domestic cantaloupe had no residues,
- No single fruit sample from the Clean Fifteen™ had more than 5 types of pesticides detected.
- Avocado, sweet corn and onions had no detectable pesticide residues on 98 percent or more of the samples tested.
- Multiple pesticide residues are extremely rare on Clean Fifteen™ vegetables. No samples of sweet corn and onions had more than one pesticide. More than 90 percent of cabbage, asparagus, sweet peas, eggplant and sweet potato samples had no more than one pesticide detected..
- Of the Clean Fifteen™ vegetables, no single sample had more than 5 different chemicals
Methodology
The Shopper's Guide to Pesticides in Produce ranks pesticide contamination for 45 popular fruits and vegetables based on an analysis of more than 60,700 samples taken from 2000 to 2010 by the USDA and the federal Food and Drug Administration. Nearly all the studies on which the guide is based tested produce after it had been washed or peeled.
Contamination was measured in six different ways:
- Percent of samples tested with detectable pesticides
- Percent of samples with two or more detectable pesticides
- Average number of pesticides found on a single sample
- Average amount (in parts per million) of all pesticides found
- Maximum number of pesticides found on a single sample
- Total number of pesticides found on the commodity
For each metric, we ranked each food based on its individual USDA test results, then normalized the scores on a 1-100 scale (with 100 being the highest). To get a food’s final score, we added up the six normalized scores from each metric. The Shopper's Guide™ shows a full list of fruits and vegetables in order of these final scores.
Our goal is to show a range of different measures of pesticide contamination to account for uncertainties in the science. All categories were treated equally; for example, a pesticide linked to cancer is counted the same as a pesticide linked to brain and nervous system toxicity. The likelihood that a person will eat multiple pesticides on a single food is given the same weight as the amounts of the pesticide detected and the percent of the crop on which pesticides were found.
The EWG’s Shopper’s Guide™ is not built on a complex assessment of pesticide risks but instead reflects the overall pesticide loads of common fruits and vegetables. This approach best captures the uncertainties of the risks of pesticide exposure. Since researchers are constantly developing new insights into how pesticides act on living organisms, no one can say that concentrations of pesticides assumed today to be safe are, in fact, harmless.
The Shopper’s Guide™ aims to give consumers confidence that by following EWG’s advice, they can buy foods with consistently lower overall levels of pesticide contamination.