As you may already know, the Environmental Working Group is a 501(c)(3) NGO with the goal of protecting “kids from toxic chemicals in our food, water, air and the products we use every day”. One of their major efforts is the yearly Shopper’s Guide to Pesticides™.
EWG gives many many reasons why they think you should use the guide, specifying that you (the consumer) should eat organic or at least choose the Clean 15™ over the Dirty Dozen™:
The 12 most contaminated fruits and vegetables (the “Dirty Dozen”) are contaminated with an average of 10 different pesticides, with many tainting more than one type of produce. In contrast, the “Clean 15,” the 15 least contaminated fruits and vegetables, contain an average of less than 2. Eating organic food lowers pesticide body burdens as well. Research shows that concentrations of pesticides in children’s bodies peak during seasons that they eat the most produce, but fall to below detectable levels in just 5 days when they eat organic food.
The list of reasons has a lot of scary facts about how many pesticides detected on food, just how “polluted” our bodies are from the things we
Unfortunately, I’m not sure if anyone gets to that part, considering that media coverage of the Shopper’s Guide rarely mentions it, instead focusing on the scary facts (as in ‘Dirty
The truth is, pesticides are scary. As EWG’s Amy Rosenthal says, “Pesticides are designed to kill things.”
The devil, as always, is in the details.
We need the EWG
Before we get into those details, I’d like to say a few things about the Environmental Working Group in general, or really any group that does what EWG tries to do. EWG has the ability to provide a very important benefit to society. Government spending on science has decreased over the years, leaving most toxicity research to the companies that make the products being tested.
Until we follow the leadership of India and develop a network of government certified independent testing labs, we’re all kind of left with less information than I’d prefer for many products we use every day. It’s not that I think every corporation is driven by people who choose profits over safety (on the contrary, they have to at least think their products are safe or suffer bad press or worse if people get sick) but results of corporate-funded tests are often not made available to the public which leaves regulators with less info than they need to make good science-based decisions.
Our system works fairly well (the grand majority of people get through life without health problems caused by things they can’t control other than their own genetics*) but it could always be better. EWG works to get information to regulators and presents a non-industry point of view, which is much needed. Unfortunately, despite their outwardly awesome intentions, some of the results are less than awesome.
In the materials accompanying the Shopper’s Guide, there are two details that are never discussed.
The first elephant in the room is
The second elephant is the type of pesticides that were found on produce. There isn’t any weighting in the Shopper’s Guide of individual pesticides based on relative toxicity. This could be a problem because not all pesticides are created equal. Organophosphates, for example, are extremely dangerous because they affect cholinesterase, an enzyme that is essential for the human nervous system. Glyphosate, on the other hand, affects EPSPS, an enzyme that is only found in plants so human toxicity is low (surfactants and other ingredients in
Careful consideration of dose and toxicity of pesticides on produce may mean a reordering of the list is necessary in order to truly keep consumers safe. It may also mean that many of the scary facts need some sober facts alongside to help us keep things in perspective. Let’s look at
I have to tip my hat to EWG for providing their methods on their website. I don’t know how many people look at it, but I certainly did! They provide justifications for not discussing dose or type of pesticide:
The goal is to include 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, and the likelihood of eating multiple pesticides on a single food is given the same weight as the amounts of the pesticide detected or the percent of the crop on which pesticides were found.
The problem is that, as strange as it may sound, there are safe amounts of pesticides. With the incredibly low detection limits that advanced methods provide us, we can expect many positive results that aren’t biologically significant. This is why the EPA bothers to determine tolerance limits for each pesticide (see below: The Data). The EWG continues:
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 and gives shoppers confidence that when they follow the guide they are buying foods with consistently lower overall levels of pesticide contamination.
In other words, science-based risk assessment is bad because it’s complex? A less complex and unscientific method gives consumers more confidence than a science-based method? Perhaps, but this explanation of the method is a little too close to fibbing for my taste. Maybe we need to look deeper.
EWG looked at contamination in 6 different ways:
- “Percent of samples tested with detectable pesticides.” Assuming that the data was used properly, this is a good metric. It tells us how many of all the samples within a category had pesticide residues.
- “Percent of samples with two or more pesticides.” This metric might be useful if we are concerned about potential effects of consuming more than one pesticide.
- “Average number of pesticides found on a single sample.” This isn’t as useful as a median number of pesticides could be. If most of the samples contain 0 pesticides, the average would be lower than the median. If only one of the samples contains a very large number of pesticides, the average would be artificially high.
- “Average amount (level in parts per million) of all pesticides found.” Here’s where the science gets thrown out. The type of pesticide isn’t considered even though we know that some pesticides are dangerous at low doses while other pesticides are safe at much higher doses. The ppm of different pesticides should not be averaged unless they have similar toxic doses. No where on the Shopper’s Guide site is there a discussion of how the pesticide levels found in produce match up to EPA guidelines, or how those guidelines are created (in most cases the guidelines from the EPA are at least 10 times lower than the actual dangerous dose).
- “Maximum number of pesticides found on a single sample.” This isn’t very useful either. Perhaps one sample was grown by a particularly zealous farmer who used more pesticides than she should. Perhaps the single sample was accidentally contaminated. Should the entire category of produce be condemned because of this single sample, out of hundreds of samples? Using the median number of pesticides for all of the samples make much more sense.
- “Total number of pesticides found on the commodity.” Again, this number could be based on one or a few samples which are not representative of all of the samples.
Since 1991, the Agricultural Marketing Service (part of the USDA) has collected data on pesticide residues in food as part of the Pesticide Data Program (PDP) using pretty rigorous methods (pdf). In addition to this testing, the FDA tests domestic and imported food to ensure that pesticide residues are below the tolerance levels (FDA probably doesn’t test enough samples due to funding cuts but that’s another post).
The results are compared to tolerance levels (maximum pesticide residue limits) that are set by the EPA (you can find the tolerance for each crop/pesticide/country combo at Maximum Residue Levels database). According to the Latest PDP Findings of Interest to Consumers (pdf), “the vast majority of samples tested are well below the tolerance levels”. Specifically:
PDP tests high consumption foods using highly sensitive instruments to detect pesticide residues as low as 0.001 ppm, which is considered trace levels of residues. Residues detected in foods tested by PDP are reported in a great majority of samples below 1 part per million (ppm).
The USDA provides some comparisons to help us understand what 1 part per million is: 1 ounce of salt in a mountain of 62,500 pounds of sugar or 1 ounce of dye in 7,350 gallons of water
For samples containing residues, the vast majority of the detections were well below established tolerances and/or action levels. Before allowing the use of a pesticide on food crops, EPA sets a tolerance, or maximum residue limit, which is the amount of pesticide residue allowed to remain in or on each treated food commodity. Established tolerances are listed in the Code of Federal Regulations, Title 40, Part 180. In setting the tolerance, EPA must make a safety finding that the pesticide can be used with “reasonable certainty of no harm” and that residues at (or below) the tolerance are safe. The reporting of residues present at levels below the established tolerance serves to ensure and verify the safety of the Nation’s food supply.
To restate, the methods used to detect pesticides are very sensitive, but a positive sample does not indicate a problem unless the detected level is above the established tolerance level. “A tolerance violation occurs when a residue is found that exceeds the tolerance level or when a residue is found for which there is no established tolerance.”
There were 60 samples that exceeded tolerance levels, making up 0.5% of all the samples (58 with 1 residue exceeding the tolerance and 2 with 2). There were 442 samples that had pesticide residues that don’t have established tolerance levels, making up 3.7% of all the samples (one reason why there isn’t an established tolerance level is that the pesticide in question isn’t labeled for use on the specific crop being tested). “In most cases, these residues were detected at very low levels and some residues may have resulted from spray drift or crop rotations.”
Starting on page 51 of 202, the results are presented in a table the includes the number of samples tested, the number of positive samples by pesticide type, the amount of pesticide detected, and the EPA tolerance for that pesticide. I encourage you to see the report for all the details. The data can be downloaded from the Agriculture Marketing Service.
There do seem to be some discrepancies between what EWG says the USDA data says and what the USDA data says
The EWG says “more than 96 percent of peaches tested positive for pesticides”, and “peaches had been treated with more pesticides than any other produce, registering combinations of up to 67 different chemicals.” That sounds pretty bad
Table 3 of the 2008 USDA report lists the “Number of Samples Analyzed and Summary of Results per Commodity” (page 34). According to this table, 616 peach samples were analyzed, with an average number of 130 different analyses conducted on each individual sample, resulting in a total of 80,184 tests done on the 616 peach samples. Of these tests, 2,155 were positive for pesticide residues, and 52 different pesticides were detected. While the number of positive detections out of all the tests isn’t the same as the number of positive samples out of all the samples, it is still interesting to know that only 2.7% of all the tests conducted on peaches were positive.
52 isn’t 67. 2.7% isn’t 96%. What’s happening here?
EWG didn’t use the most recent data. Instead, they seem to have combined data from 2000 to 2008. That seems very strange to me, considering that EPA regulations for allowed pesticide use and allowed pesticide tolerances have been changing over the years, becoming more strict. At least they didn’t include pre-2000 data, but
If not scary “facts”, then what?
I am definitely an advocate of using science-based approaches to farming that reduce input use overall, and of careful Integrated Pest Management strategies that use the safest possible solutions to any pest problem, only using inputs if other options have been unsuccessful, and using the safest possible pesticide whether that pesticide is natural or synthetic.
How do we encourage the government to introduce regulation that will make this happen and how do we encourage consumers to care about this enough to talk to their elected officials?
The best course of action would be to present the information in a less agenda driven way. Provide the data along with the EPA guidelines, which would show that the great majority of produce is well within guidelines. There are ways to advocate for reduced pesticide use without alarming people unnecessarily.
* In the developed world, health problems caused by our own choices (bad nutrition, lack of exercise, smoking, and so on) dwarfs any problems that might be caused by normal use of household chemicals, plastics, foods, etc.
Note: A group called Alliance for Food and Farming, called an “industry front group” by EWG has challenged the Shopper’s Guide, saying that it unnecessarily alarms consumers. I have not read any materials from AFF on this subject prior to writing this post to be sure that my comments were not based even subconsciously on their comments. I heard about the AFF response through the Iowa State Sustainable Agriculture Listserv, which led me to write a few responses about the Shopper’s Guide to the original poster which then were turned into this post. This year’s Shopper’s Guide came out in June 2010.
Amusingly, just after I published this, my mom sent me Prevention Magazine’s Dirty Dozen article. As least they remind us that more fruits and vegetables are better than less, even if there may be pesticide residues – but they don’t tell us this until after they scare the pants off us. Sigh.
In a way i disagree with your analysis (could be my ignorance) of the “percent of samples tested with detectable pesticides” metric. I think given how low of a dose we can detect it seems this isn’t that useful. I also would like to see a comparison with natural pesticides and how many are on organic food.
Awesome post. I’ve also run across this “dirty dozen” list, in the course of a websearch to try to find crops ranked by average total pesticide application per acre (a very different statistic).
If there were 616 peach samples analyzed and 2,155 positive tests, that’s an average of ~3.5 positive tests per sample. I’d say the EWG’s 96% number for the number of samples that showed detectable (not dangerous) levels of any of the pesticides tested sounds credible.
However adding in pesticides that were detected years ago but not today is much more problematic on their part. If nothing else that means crops that have transitioned from an older set of more toxic pesticides to a completely different set of less toxic ones today could potentially show up as having twice as many pesticide residues detected!
Anastasia, some things I noticed when I perused their website.
1.) I didn’t see how they tested for pesticides. Did they use NMR or what? Did they take outside samples? Samples of the edible parts? This is important because I’m pretty sure you could douse a banana or orange in pyrethroids and still have a low enough concentration of insecticide to feed to a cockroach colony safely.
2.) This is probably the most important metric, but I didn’t see what pesticides they tested for. Did they test for biopesticides? If so, were those naturally occurring or were they applied by the farmer? How could they tell? Did they exclude insecticidal/fungicidal/antimicrobial compounds exuded from the plant itself?
Let’s use oranges as an example. Split open an orange with your thumb and you’ll get the classic ‘orangey’ smell. That ‘orangey’ smell is caused by a substance called limonene and the plant most likely produces it as an antifeedant.
Limonene is used in insect repellents, scented candles, soap and as an industrial solvent. If they tested oranges for limonene, it would undoubtedly come up positive.
Elsewhere on the site, they used IUPAC names to refer to pesticides. I generally see that on crank sites which try to scare people with big, scary words.
I call BS, as well.
The tests weren’t done by EWG. These groups rarely do research themselves or fund research (actually never, as far as I know), they just misinterpret other people’s data. The pesticide data here has been collected by the USDA each year since 1991 with appropriately rigorous methods.
Nice piece. Particularly liked the reference to the AFF piece and your decision to write this first.
There appears to be a typo in the second last bullet point:
Using the media number
where I think you meant “median” instead. Its an unfortunate misspelling because the current discussion concerns numbers placed in discussion by the media.
Hope all your corn pollination has gone well thus far. Finished up yet? Here in Ohio we’ve just finished soybean cross pollination for another season.
Excellent and comprehensive critique of the EWG’s effectively anti-health agenda. Toxicity is not something that most of us have been educated to understand. Our morning coffee, our salsa or our over the counter pain medications are actually the major toxins to which we are exposed. Trace pesticide residues are insignificant in comparison.
how exactly are any of those “toxins” in dosages that are for pain meds recommended, for coffee most people use and how in the world is salsa a “toxin”
The old saying is, “the dose makes the poison” as almost everything is toxic at some dose. Caffeine and Capsaicin(what makes hot sauce hot) are natural chemicals which are actually fairly toxic (in the range of 250 mg/kg). Because we consume them at doses around 100 times lower than what it would take to hurt us, there is no problem. Pesticide residues of the type the EWG targets are at levels thousands of times lower than a toxic dose. Ibuprofen in Advil has a toxicity of 600 or so mg/kg. It would take 173, 200mg pills at once to hurt even a 120 lb person. The bottom line is that we all consume lots of low level toxins every day, and if we ignore irresponsible groups like EWG and eat lots of fruits and vegetables we also consume lots of beneficial chemicals as well
Well my point is why care much about being exposed to things at below toxic levels? Something isn’t “inherently” toxic that even at low levels the stuff hurts us.
I’m not sure I understand your last comment. Yes, there is an issue of long-term exposure to substances at levels well below toxic dose. Things like pesticides and pharmaceuticals are tested for that as best we can. Natural toxins are not tested because there is no one who wants to pay the millions of dollars that such studies cost.
Steve – I think Zach’s issue is with how you appear to be framing the facts – your initial post can be taken in such a way that it appears that you are overly concerned about natural toxins rather than as it was intended (at least as I read it) that as we aren’t at all concerned about natural toxins at the levels we consume them then we shouldn’t be concerned about residues of toxic pesticides – as all these toxins are present at levels which do not cause any issues.
The key point being that when talking about toxins you really have to talk about dosages – something that isn’t often done in any discussion of the subject (at least around pesticides and GMOs in general as far as I’ve seen) – the word toxic is raised, this is automatically a bad thing, and therefore anything to which the word toxic can be attached should be banned etc.
Thanks for pointing out the typo! It’s been fixed.
Corn pollination in Iowa is still going strong, the plants are all developing at different rates due to field flooding. Do you pollinate soybean by hand? I’ve heard that not easy to say the least.
thanks for the clarification. You are exactly right, we are actually well designed to eat low levels of toxins because our intestinal lining cells only live for three days before being replaced. That means we can deal just fine with exposure to the natural toxins. The pesticide residues are present at far lower levels so there is really no reason to worry about them at all
We do pollinate by hand (with a tweezers to be precise). It is more tedious than corn pollination, but we do have the advantage of working with a self-pollinated crop so that we only need to cross pollinate to develope new segregating populations. Down stream you’re self pollinating your F1s and subsequent generations to control pollen source… and we get to let Mother Nature do that for us.
Guys, there are so many overly simple generalizations about toxins.
Each toxic substance acts on the body in its own way. The relation of dose to toxic effect is different for different toxins.
There are actually some toxic substances that are beneficial in small doses but harmful in larger doses, such as the heart drug I take every day.
There are other toxins that are harmful when ingested occasionally but for which a tolerance can develop after a long time.
Some toxins are metabolized and others accumulate.
I don’t know how you counter propaganda about pesticides when the propaganda is determined to selectively distort the issue.
Toxins are really complicated. One thing I wish more people would keep in mind is that there are some things we do in life that have way more effect on our overall health, cancer risk, etc than trace exposure to household cleaning products, pesticides, etc. I don’t mean to say that there shouldn’t be rigid testing and all that good stuff but let’s put things in perspective!
The Environmental Working Group is part of the Tides Foundation’s constellation of activist franchises, sometimes referred to as the ‘Green Mafia’. In lieu of describing the Foundation’s byzantine accounting practices (with a nifty real estate scam on the side), I’ll just point out that this latest ‘report’ by the EWG is most likely bought and paid for with tax-deductible ‘donations’ by the organic industry.
I have been reading your original post and the comments. Although there is a great deal that can be said about the Environmental Working Group that shows who and what they actually are, I don’t intend to do that here now….perhaps in another post. However, what I really wish to address is the idea that any exposure at any level is dangerous if it has been shown to be dangerous at higher levels.
This is now and has always been scientifically false, in spite of the Delaney Clause of FIFRA. At some point the molecular load of any chemical will be so small that the cells won’t respond to it. Furthermore, the amount of pesticides that are naturally occurring is far higher than anything we are exposed to in the food we eat. The base premise of the EWG is based on the false premise that a detectable presence is a toxic presence. With the advancement of modern detection techniques it is unlikely that we aren’t going to be able to find everything in everything at some point.
This comment was posted on Facebook, and I think the commenter brings up some good points relevant to this post, so here it is, along with my reponse.
Interesting article. I use to know some of the folks at EWG (when I working at cdph) and think that, in general, they do a pretty good job of taking complex scientific data and translating it for laypeople. This, I’m sure you know, is not always easy to do. I have a few thoughts on what she wrote. I don’t think it’s a negative post, but there are some things I’d like to say. First, one of the reasons I try to buy organic is that I feel like I’m doing a better job of supporting ag workers, who often get sprayed along with the crops being dusted by the pesticide planes flying overhead.
Second, when she talks about safe levels, she sort of implies that established safe levels are based purely on scientific data, which is not true. levels are ultimately decided by a combination of data and politics. Industry is heavily involved in the process. Also, as recently as 8 years ago (the last time I was really steeped in this stuff), the science that determines safe limits was based on what a safe allowable load would be for an average sized full grown man, which means that the level may not be safe for children, women, the immuno-compromised etc. This could have changed, I’m willing to listen to someone who has more recent knowledge. Also, levels change as data accumulate – lead and mercury are perfect example. As is DDT. I think her suppositions on why certain data points are worthless are based on a premise that the “safe” levels out there are just that – safe.
Finally, it’s hard to look at pesticides and judge them as discrete chemicals. I think you do have to look at accumulation and interactions and right now, the way rules are written, companies don’t have to look at that or prove that kind of safety when they present their data.
I don’t think EWG is saying that complex risk assessment models are a bad thing. And I certainly think people need to eat more fruits and vegetables even if they can’t afford organic.
I agree that the conditions of workers is one important consideration when choosing what products to buy. However, I don’t think that always means organic is better.
In the US at least, there are very strict regulations about pesticide use and where workers are allowed to be during and soon after pesticides are applies. EPA and OSHA both have regulations regarding worker exposure for both persons applying pesticides and those who work where pesticides may be used. Of course, not everyone follows the rules, but for the most part the regulations work.
If you buy produce from other countries, those regulations regarding worker exposure might be less strict or not exist. Still, buying organic might not make a difference anyway, as some recent studies have found foods labeled “organic” to have non-approved pesticide residues on them anyway (in short, farms are cheating).
If we’re really concerned about worker welfare we also have to consider non-pesticide related issues. For example, organic methods of weed control include hand weeding, which if you’ve ever weeded you know is horrible backbreaking labor. Organic methods of insect control can include picking insects off plants manually (particularly in countries where labor is cheap, also, children are well suited for this task, unfortunately), and either pesticides or the genetically engineered trait Bt can control without that labor.
Regarding what the EPA bases tolerances on – from the EPA website: “In August 1996, the Federal Food, Drug, and Cosmetic Act was amended to include the Food Quality Protection Act or FQPA. This Act required EPA to reassess by August 2006 all of the pesticide tolerances that were in place in early August 1996 to ensure that they met current safety standards and were supported by up-to-date scientific data.” They also reevaluate whenever there is an objection filed or if a study comes out indicating a tolerance is set too high.
http://www.epa.gov/pesticides/regulating/tolerances.htm The important thing to remember here is that the tolerance levels are actually set an order of magnitue or more higher than the actually dangerous level, to account for the difference between safe levels for healthy adults vs children, elders, etc.
Finally, as I said in the post, I think EWG is generally a force for good. But I don’t know how they can justify putting out materials that scare people out of eating fruits and vegetables. EWG counts trace amounts of a pesticide known to be fairly benign as equal to a large amount of a pesticide known to be dangerous. That’s just irresponsible. Regardless of how valid or not valid their methods are, EWG isn’t being responsible in how they present their findings. Their little disclaimer that people should still eat produce is not enough. Take a look at this acticity for children from the California Academy of Sciences, for example http://www.calacademy.org/teachers/resources/lessons/pesticide-watch-card/. It instructs teachers to show children how dangerous their favorite fruits and vegetables are, based on the EWG information. How many of those impressionable kids avoid produce after that demonstration, possibly for life? What if their parents can’t afford organic produce? It is possible to advocate for reduced pesticides without scaremongering – EWG needs to learn how to do that.
Could you point to one or two of these studies please?
The Environmental Working Group is nothing more than a scare factory that only exists if it can generate scares long into the future. The fact that pesticide residues are detectable is meaningless without determining the dose, and pesticide residues on food is so low that it means nothing to our health, other than the fact they these residues are the end result of wonderfully high production and low cost for life saving products….food!
As Dr. Bruce Ames notes; you will receive more carcinogens in one cup of coffee than the entire pesticide residue on all the food you will eat in one year. We almost have the ability to detect residues of virtually everything in a glass of water now….that doesn’t mean that it matters to our health or has any impact on our lives.
Regarding the comment about the determination of safe levels of pesticides being political…he is right…but only in the converse. From the very beginning there was a hundred fold safety factor tied up in the use of pesticides. First they added a tenfold safety factor regarding intra-species testing, the another ten X safety factor for inter-species bringing it up to a hundred fold safety factor and then the Food Quality Protection Act added another ten X, making it a thousand fold safety factor….and all of this is based on risk assumptions, in other words it was a political move and had nothing to do with science, and industry had nothing to do with that. It was the people at EPA who are indistinguishable from the irrational misanthropic anti-pesticide EWG people.
Everything we are told should bear some resemblance to what we see going on in reality. In reality those countries that have been the biggest pesticide users are the best fed people on the planet and live longer, healthier lives than ever in human history.
I just saw something about this on Twitter a few days ago but now I can’t find the article. There’s many reports about fake organic, though, I just googled “fake organic” and found a few articles, such as Fake organic foods proliferate from China. The recent article I can’t find (I’ll post it here if I find it) talked about how there aren’t enough inspectors so any single farm overseas might never be inspected to see if they are really using organic practices or not.
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