Pesticide Residues in Our Food - What Does It Really Mean?
by Miranda Holmes
For the past eight years, the Environmental Working Group (EWG) has been analysing the pesticide testing done by the United States Department of Agriculture (USDA) and the Food and Drug Administration (FDA).
EWG’s annual Shopper’s Guide to Pesticides in Produce ranks pesticide contamination for 45 popular fruits and vegetables, measuring the contamination in sixdifferent ways:
• Percentage of samples tested with detectable pesticides
• Percentage 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.
It is worth noting that the majority of studies on which the guide is based involved testing samples after they had been washed or peeled – alarming for consumers who believe these measures to be adequate protection from pesticide residues.
The guide flags the 12 most contaminated fruits and vegetables and the 15 least contaminated. Full details from the 2012 guide are available at www.ewg.org/foodnews.
Amongst the findings of the 2012 guide :
• 98% of apples sampled had detectable levels of pesticides.
• Domestic blueberries tested positive for 42 different pesticide residues.
• 78 different pesticides were found on lettuce samples.
• Every single nectarine USDA tested had measurable pesticide residues.
• As a category, grapes have more types of pesticides than any other fruit, with 64 different chemicals.
• Thirteen different pesticides were measured on a single sample each of celery and strawberries.
• 52 pesticides were detected on sampled peaches, including residues of highly toxic organophosphates.
This year EWG added an extra category (Dirty Dozen Plus) for green beans, kale and collard greens. Although these vegetables did not meet the normal criteria for inclusion in the top 12, they were flagged as foods to avoid because, along with bell peppers and nectarines, they showed potentially unhealthy levels of organophosphate (OP) residues.
OP insecticides are known neurotoxins. Although their use in agriculture has decreased in recent years, exposure is still widespread.
3 Sweet bell peppers
6 Nectarines (imported)
A study by Stephen Rauch of BC Children’s Hospital (published earlier this year in Environmental Health Perspectives) linked prenatal OP insecticide exposure with lower birth weight and shorter gestation. Rauch notes that these pregnancies began after OPs were restricted for most uses. He also flags other studies linking prenatal exposure to OP insecticides with abnormal reflexes, reduced cognitive abilities, and attention deficit/hyperactivity disorder (ADHD).
All of which makes another new element of EWG’s annual guide particularly alarming.
This year, for the first time, the USDA also looked at pesticide residues in baby food.
Nearly 200 samples each were tested 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 OP methamidophos (found in 9.4% of samples) and the OP acephate (7.8% of samples).
According to EWG’s calculations: “A 22-pound (10kg) child eating one four-ounce (113g) serving of green beans sold as baby food with the maximum methamidophos level found would consume 50% 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 even greater risk.”
Pears prepared as baby food showed significant and widespread contamination, with 92% of samples testing positive for at least one pesticide residue. More than a quarter of samples were tainted with five or more pesticides. The pesticide iprodione (identified as a probable human carcinogen) was detected in three samples.
EWG notes that iprodione is not registered for use on pears and that its presence in this popular baby food “constitutes a violation of FDA regulations and the federal Food, Drug, and Cosmetic Act”.
One bright note is the fact that sweet potatoes (included in EWG’s Clean Fifteen list) used in baby food had virtually no detectable pesticide residues.
2 Sweet Corn
6 Sweet peas
11 Cantaloupe (domestic)
12 Sweet potatoes
How Clean Are the Fifteen?
The EWG guide stresses that consumers should opt for organic when purchasing fruit and vegetables on the Dirty Dozen list.
The group also emphasizes that produce on its Clean Fifteen list are not necessarily free of pesticide residue. They are simply the least likely to be contaminated.
What they do state is that the majority of these fruit and vegetable samples had no detectable pesticide residues and, of those which did, multiple pesticide residues were extremely rare.
What Does This Mean in Canada?
According to Statistics Canada, nearly 60% of our food imports (in dollar terms) come from the US, the vast majority of which is fruit, vegetables and fish. It is therefore reasonable to assume that pesticide residues are imported with this produce.
More importantly, in 2010 Health Canada and the US EPA adopted the Organisation for Economic Co-operation and Development (OECD) standards for maximum residue limits (MRLs) for pesticides in food. So the allowable pesticide residues for Canadian-grown fruit and vegetables are the same as those for the US produce detailed in the EWG report.
The Canadian Food Inspection Agency (CFIA) does test produce for pesticide residues, but only flags for concern the samples which exceed their MRL. For example, a May 2012 CFIA report on apples, tomatoes, lettuce and small berries simply stated that 99.6% were at or below their MRLs. Of the 11 samples which failed, CFIA stated: “Further assessment determined that these products would not pose a health risk to consumers.”
In announcing the adoption of the current standards, Health Canada said: “Both Health Canada and EPA agree that the OECD MRL Calculator provides statistically robust and scientifically-defensible MRLs.”
Meanwhile in Europe
Health Canada may consider its pesticide residue standards defensible, but they are certainly not the most stringent.
The MRLs set by the European Union are often much lower than Canada’s. Taking just two examples from the pesticides flagged above:
• At 25 parts per million the current Canadian MRL for iprodione is two and a half times higher than that set by the EU. (The recent CFIA survey found iprodione residue on 56 samples of berries – strawberries were the highest at 33).
• The Canadian MRL for the OP methamidophos is 10 times higher than the EU MRL. (CFIA also found residues of methamidophos on 12 lettuce.)
Miranda Holmes is a former journalist and toxics campaigner. She is now an associate editor of Watershed Sentinel.
The Environmental Working Group 2012 Shopping Guide to Pesiticide can be found HERE
[From WS September/October 2012]