Tag Archives: USDA/EPA

How Dirty is the Dirty Dozen?

EWG protest photo-1I have a confession to make: I have, on a few very limited occasions and against my better judgment, bought organic produce because I thought it was better for my family. Shocking, I know. I just wrote a story about what a good job I think the EPA and the USDA do to help ensure our produce has safe, minuscule levels of pesticide residue. How could I be so hypocritical? The answer is fear in parenting. Like so many other parents, I was (marginally and with doubts in my mind) temporarily frightened by media reports that perhaps some produce contained dangerous levels of pesticides and we would be better off with organic. Where would I get that idea? From a list called the Dirty Dozen. Rest assured, though, I have regained my composure and I am back on the conventional produce horse. Worry not, it won’t happen again, because now I know more about how wrong the Dirty Dozen list is than I used to.


The Dirty Dozen is a list put together every year by a group called the Environmental Working Group. The EWG is a US-based environmental advocacy organization that takes on issues ranging from sunscreen to genetic engineering to cell phone towers and cosmetics. The EWG is well known for the Dirty Dozen list which uses publicly available data to rank produce according to levels of pesticide residue.  The list has been expanded to include the top 15 “dirtiest” produce; those the EWG has determined have the most pesticide residue. The EWG recommends consumers buy organic options of these “most contaminated fruits and vegetables.” The group also puts together the Clean Fifteen, which is a list of fruits and vegetables that fall at the bottom of the EWG’s ranking system for pesticides, ones you can buy conventional without feeling badly about it.

As you might expect, this concept is popular among parents. We’re always trying to balance doing the very best thing for our kids with the impact to our bank accounts. Not everyone can afford organic, so it’s inviting to hear someone say: “hey, don’t sweat it, you don’t always have to buy organic! Just focus on these specific items.” That helps parents feel good. They can check the “doing the right thing” box and move on.

It’s not surprising many parents use this list – the media regurgitates the Dirty Dozen like a mother bird feeding hungry chicks. The EWG packages its message in tidy little soundbites that basically write the stories themselves. Everyone covers it: CBS NewsCNNHuffington PostGood HousekeepingForbesFox NewsShapeWebMDPBS, even Oprah. I could go on and on, all you need to do is a simple Google search.

Seems legit, right? While I have heard the Dirty Dozen talked about in mom circles for years, even enough to convince me to throw a few extra dollars at the idea once or twice, I never actually looked at the EWG’s website to see where the data came  from. I recently did a casual Facebook survey to see how much my mom-friends know. Of the 24 who responded from across the US, 83 percent had heard of the Dirty Dozen and 75 percent could name two items on the list. Conversely, only 21 percent knew who was behind the Dirty Dozen, and only 8 percent had an idea about how the list was put together.

So how is the list created? Turns out, not very scientifically. The EWG states on its website that it uses data available from the USDA and FDA to create six evenly-weighted metrics to rank produce. Not a single one takes the tolerance level (what the EPA deems a safe exposure level) of the pesticide into account; the metrics and methodology don’t consider whether the amount present is actually a problem or not. The EWG’s metrics are instead weighted to basically vilify the mere existence of pesticide residue without consideration of whether the amount present is within the safety limits set by the EPA.


Not only are these metrics pretty questionable, but the EWG doesn’t make the subset of data it uses available for the public to view.  Without access to the specific data from the USDA and FDA that the EWG claims to be using, it is nearly impossible for anyone to verify or reproduce the EWG’s results.  Not surprisingly, this also makes it difficult to refute or differently interpret the EWGs findings. Nowhere on its site does the EWG even link to the USDA or FDA’s websites. I think I figured out where the EWG gets the numbers, but how would you know for sure if it isn’t said? After looking over the USDA’s Pesticide Data Program reports, I’m still not certain how all six of those metrics are determined or how the ranking system is created. Now, I’m not a scientist, so maybe it’s easier for someone familiar with that data to figure it out. But when you ask scientists, the consensus is disagreement with the EWG’s Dirty Dozen list.

In 2011, the Journal of Toxicology, a peer-reviewed scientific journal, published a study that concluded the EWG’s methodology does not follow any scientific procedures and does not back up their claim that you can avoid pesticides by eating organic varieties of the “most contaminated fruits and vegetables.” Steve Savage, a plant pathologist who has spent his career in agricultural technology, did an independent analysis of the data and concluded the EWG is misleading consumers. The Alliance for Food and Farming, a non-profit group made up of farmers and farm organizations, commissioned an expert panel of five scientists (one of whom has 22 years of experience at the EPA) to evaluate the EWG’s Dirty Dozen and those scientists concluded it is unscientific. Forbes contributor Henry I. Miller did an opinion piece on the EWG’s unscientific-ness, which I thought was great, but sadly it was an opinion piece, not a news article.

Does anyone else find it ironic that we, as consumers, demand that scientists back up their claims with data and peer-review before we even reluctantly (read the comments) consider them, yet moms seem convinced by what appears to be an unscientific, intentionally opaque analysis that isn’t peer-reviewed? Clearly, this gets me fired up.

So I reached out to Teresa Thorne at the Alliance for Food and Farming to talk to her about what the science really says. Her bottom line was that moms should not be afraid to feed their kids fruits and vegetables. “We don’t advocate for organic or conventional, whatever choice you make is the right one for your family when you’re choosing to eat fruits and vegetables,” she said. Thorne said the Alliance is concerned that the EWG is using fear and language that is making people hesitate to buy produce. “Moms deserve truthful, credible information. There are decades of research showing it’s safe; farmers are doing a very good job.”


Thorne also had questions about the EWG’s methodology and lack of information on its website. “In today’s world, when you are putting out a new report or study, why wouldn’t you reference the USDA data you use?” Thorne said.  “Why don’t they link to the data? The answer is the EWG doesn’t want people to know what the USDA and EPA say. Because they say it’s safe.” The USDA just recently released the newest Pesticide Data Program results, again confirming that pesticide residues do not pose a safety threat. Thorne encourages consumers to read that report, but if they don’t want to read the whole report (and it’s long, trust me) at least look at the press release and look at the USDA’s “What Consumers Should Know” sheet about the report. “The EWG manipulate that data and turn it into something very negative, when the government report is very positive,” said Thorne.

Interestingly, let’s take a listen to what the mainstream media has reported on the recent USDA report saying our fruits and veggies are safe: … [insert sound of crickets chirping] … nada.

The EWG often argues that the EPA’s safety limits are too lax and if consumers want to be sure they’re safe they should eat organic. But Thorne brought up a good point that organic consumers might not think about. “The fact of the matter is that the laws and regulations are stringent and protective,” Thorne said.  “Those laws and regulations aren’t just protecting consumers for conventional produce; they’re also for organic produce. Organic pesticides go through the same scientific process as conventional ones. It’s dangerous to damage that credibility unjustifiably. Doesn’t that undermine both?” That’s an interesting point. Especially since, as far as I know, the USDA doesn’t test organic produce for residues of approved organic pesticides.

I also reached out to the EWG for clarification on some of these issues: namely why it doesn’t link to the data, present the data on its website, or submit to peer-review? Also why doesn’t the methodology take tolerance into account, and what’s the EWG’s stance on organic pesticides? After some back and forth, I was told they won’t answer my questions until after they release the 2014 list later this week. (I get it; I used to work in PR.) So I’ll get back to you on that. I’m planning a follow-up article on the media coverage of this year’s Dirty Dozen and I will include the EWG’s answers to those questions.

We can anticipate that the EWG is going to, yet again, misconstrue the USDA’s positive report this week when it releases the 2014 Dirty Dozen list. The EWG will take that data and twist it around and try to convince you to buy organic options to help protect your family from “harmful pesticide residue”. Don’t fall for it. Don’t let the media feed you information and don’t let an activist group make decisions for you about what’s safe and what’s not. Use your Mom Sense, look into the science, and reach your own conclusions.



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Peeling Potatoes: Worth It or Not?

potato parade-1Recently I was at a friend’s house for dinner with my family. I was chatting with my friend while she was putting dinner together, and while she was peeling the potatoes I remarked offhand that I never peel potatoes because I’m just lazy and it’s too much work. She said, “You’re going to think this is silly, but I’ve read lots of stuff about pesticides concentrating in the peel. Potatoes are on the dirty dozen list and I’m not sure how true that information is, but I feel like it’s a pretty easy way to avoid that. I even read that conventional potato farmers don’t eat their own potatoes, they grown a small organic plot for their families.” I said while I had never heard of pesticide residues concentrating in the peel, I seriously doubted potato farmers don’t eat their own crop. Based on the farmers I’ve met, my impression is that they’re extremely proud of what they do and likely they eat what they grow. But, I said I’d look in to it because I thought it was interesting. After slogging through lots of data and talking to some folks in the field, I’ve concluded you’re not really avoiding pesticides by peeling the potato, but you are reducing the nutritional value you gain from eating potatoes when you take the peel off.

Let me start by saying that this friend of mine is very smart. She used to be a science teacher and has a bachelor’s in microbiology and a master’s in immunology.  I respect her quite a lot, which is why I decided to look into it. If a rational scientifically educated person accepts this, then average consumers with less science reasoning background likely will also.  I did a google search, and I can see where she got that idea.  The media loves to cover the Environmental Working Group’s “dirty dozen” list, and potatoes are tenth on the list. Just google, “do potato farmers eat their own potatoes” and you’ll see what I mean. The Dr. Oz show recently had Dr. Alan Greene on his show claiming he won’t eat conventional potatoes because of their high levels of pesticide residue.  This NBC News article even says that farmers “pour on the chemicals” to ensure a harvest and that you can avoid pesticides by peeling. So how true is that?

potatoes at the store-1I talked to a third-generation Washington potato farmer to find out about this idea that farmers don’t eat their own potatoes. This farmer certainly does. Not only do he and his family eat them, but they save them over the winter and eat them all year round. All of his employees also eat them, and he has family in other cities and states that beg him to bring potatoes when he visits.  He even went so far as to say he doesn’t know any potato grower or any farmer that doesn’t eat his or her own produce.  Does his family peel them? Sometimes, but that’s dictated by what dish his wife is making, not by concern over pesticide residues. (Clearly she’s not as lazy as me.) His farming operation applies pesticides to control pests (like fungus, insects, nematodes, soil borne disease, and weeds) that otherwise would damage his crop. If he didn’t use those pesticides, there would be fewer potatoes, the price would be higher, the quality would be lower, and the potatoes wouldn’t look very appealing.

He also told me that one misconception that really bothers him is that people who are unfamiliar with farming often think farmers spray pesticides just to be spraying pesticides. (Maybe because certain NBC articles say stuff like “farmers pour on the chemicals.”) “Spraying pesticide is expensive,” he told me. “The cost of an extra pesticide spray can make the difference between profit and loss on some fields.”  Farmers aren’t just spraying crops willy-nilly. They’re spraying only when they have to because it costs money and time. That’s time those farmers could be spending with their families, so they’re surely not out there spraying for kicks.

While it seems to be true that some pesticides concentrate slightly more in the peel, that’s not the whole story. The dose makes the poison, right? When discussing pesticide residues, it is very important to distinguish between the mere existence of residue and how much residue is present. What people should really be interested in is: does the amount of pesticide residue on the potato pose a risk to my health? If there is 0.01 parts per million (ppm) of residue in the potato itself, but 0.02 ppm in the peel, that’s a higher concentration in the peel. But at such a low concentration, it’s unlikely to be a health risk (of course, the toxicity of the pesticide is important, too). The risk of injury present while driving to the store to buy potatoes is likely higher than ingesting that teeny tiny amount of pesticide residue.


I also dug a little deeper into the idea that the pesticides concentrate in the peel. I talked to a chemistry expert who told me that when tolerances are set for certain pesticides, the EPA also looks at what’s called a processed fraction, or a part of the commodity that might be different than the whole commodity (like the peel.) If a pesticide concentrates higher in a processed fraction than the commodity itself, there will be a different tolerance set for that fraction. (For a refresher on what tolerance means please see my primer article on how pesticides get approved.) So, I looked up on the EPA’s website how many of the pesticides that are approved for use on potatoes have a higher tolerance for the peel. Fourteen of the 121 pesticides listed had higher tolerances for the peel. That’s about 12 percent. It’s important to note here that those 121 pesticides have tolerances set for the commodity itself, which means that there are residues throughout the potato, so you’re not avoiding them altogether by peeling.

I also looked up the USDA’s data on potatoes from their Pesticide Data Program. The last time potatoes were sampled was in 2009. Of the pesticides analyzed, only three have higher tolerances in the peel. Importantly, of those three, none were found to be over the tolerance level for the commodity (which has a lower threshold), let alone the tolerance level for the peel. For example, Chlorpropham, also known as Bud Nip, was the most commonly found pesticide in samples, and it does concentrate higher in the peel. The residues found ranged from 0.010 ppm to 23 ppm, and the mean level found was 2.5 ppm. The tolerance for Chlorpropham is 30 ppm in the commodity and 40 ppm in the peel. Not one sample was over the tolerance level for the commodity, and the vast majority was far from it!

Side note: Chlorpropham is an important tool used to prolong the shelf life of potatoes. Those little sprouts that you sometimes find on potatoes when they’ve been in the pantry too long can be toxic when eaten in high doses. The use of Chlorpropham not only helps protect you from that, but it also significantly reduces food waste.

You’d have to eat a lot of potatoes to ingest enough pesticide residues to cause a problem. In fact, there’s a website called safefruitsandveggies.com that will actually do that calculation for you. I asked it to calculate how many servings of potatoes a child could eat in one day without any effect even if the potatoes have the highest pesticide residue recorded for potatoes. The answer:  6,494 servings of potatoes.

A cup and a half of potatoes represents about the recommended daily amount of vegetables for a child.

A cup and a half of potatoes represents about the recommended daily amount of vegetables for a child.

A serving of vegetables for a child is about half a cup. So that’s 3,247 cups of potatoes you’d have to feed your child in one day before you got close to a problem. And that’s assuming every single one of those potatoes were at the highest residue level ever recorded, which we know, from PDP data, that they aren’t.  It is recommended that children have about one-and-a-half cups of vegetables per day, and the USDA tells us that children are not even getting those amounts. It would take a seriously concerted effort to get my kids to eat one and half cups of potatoes in one day, let alone 3,247 cups.

Can you really reduce your risk by peeling the potato? In short, I think the answer is that whatever miniscule benefits might be gained through peeling are likely offset by the loss in fiber and nutrients found in the peel. Twenty percent of the nutrients, and almost all the fiber, in a potato are in the peel. The residue in the peel is very small and far below tolerance; even so, most of the approved pesticides do not have a processed fraction tolerance, indicating they don’t accumulate more in the peel than in other parts of the potato. Most importantly to me, peeling the potato can’t substantially reduce a risk that isn’t there. Why is there virtually no risk? Because the amount of pesticide residue on potatoes (and produce in general) is so small that we can hardly measure it at all. That’s really more a testament to the sensitivity of the tests. The EPA and the USDA set rigorous guidelines for pesticide residues that are conservative and err on the side of being overly cautious for our safety. In practice, the residues aren’t even reaching these conservative limits.

I’m going to leave the peel on, which is good, because I’m lazy when it comes to cooking potatoes. Now I have a good excuse, though. I’m just trying to benefit from all those nutrients and fiber, I’m not lazy. That’s momsense.


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Why My Family Eats Conventional Produce

I can’t tell you the number of conversations I’ve had that go like this:

Me: Let’s go apple picking!


Mom-friend: Yes! Let’s find an organic or spray-free orchard, though.

Me: Why?

Mom-friend: I want to avoid pesticides; I just don’t think the government does enough to guarantee our produce is safe.

Me: Really? Do you know what they do during that process?

Mom-friend: Um, no. Do you?

Me: Um, no. But I bet it’s a lot.

When I hear that line of argument against conventional produce (“I just don’t trust the EPA/USDA/FDA”) I want to drag that mom over to the computer and pull up the EPA’s website and walk her through some of the information they have on their website. But, believe me, it’s not very fun. I could write a whole post on why I think the EPA, USDA and FDA need serious help organizing and clarifying the information that’s on their websites. I’ve recently looked through a lot of it, for this and some future articles, and it’s almost as fun as trying to get your toddler to find the shoes they’ve hidden somewhere in your house when you’re late (never mind, you don’t need shoes, let’s go.) Perhaps this is why few consumers actually take the time to look into what the USDA and the EPA do. It’s tedious and science-y.

I thought it would be useful to actually investigate some of the things that I don’t think parents really think about when they toss aside the extensive work our regulatory bodies do to help reassure us that conventionally grown produce (those that are sprayed with synthetic pesticide) is safe. If you don’t read any further in this article (because I am going to talk about studies and use words like “tolerance level s” and “toxicology”) I will try to sum it up for you here: They do a lot. It’s extensive and exhaustive. At the end of the day, I feel very confident that they have looked at it from all angles and have put regulations in place that err on the side of caution to reassure us our produce is safe.

getting rid of weedsBut don’t take my word for it. Let’s take a look at what happens when a company wants to start selling a pesticide. Those companies have to do both an environmental and human health assessment, but I’m going to focus here on the human health assessment. It’s a three pronged approach: toxicology studies, establishing a tolerance level and dietary risk assessment.

First, the company (who is really called the registrant) must do toxicology studies. The goal of these studies is to show what effect the pesticide could cause, and to establish a level at which there is no adverse effect in animal testing. The studies systematically expose different mammalian species (such as rats and mice) to the pesticide at varying amounts and measure the effect. The EPA outlines extensively how this must be done; it’s not left up to the registrant. They must measure toxicity arising from acute exposure, chronic exposure, and sub-chronic exposure. They measure inhalation toxicity, oral toxicity, dermal toxicity, carcinogenicity, reproductive toxicity, immunotoxicity, and neurotoxicity, just to name a few. Look here for the full testing requirements.  The goal of these studies is to literally uncover the worst possible outcome from exposure to the pesticide. They take extensive tissue samples, analyze them all and determine the dose level at which there are no observed adverse effects, called the NOAEL. Then, because the studies aren’t actually done in humans, and because sensitivity can vary across individuals, a safety factor is applied to the animal NOAEL, which lowers the dose level anywhere from 100-1,000 fold less than the observed level. Using the NOAEL and the safety margin, the EPA establishes what is called a reference dose. A reference dose is an acceptable amount of exposure to a substance that has reasonable certainty it will cause no harm (also known as the safe exposure level).

The registrant also has to do field trials to establish a tolerance level. A tolerance means, assuming farmers use the pesticide according to the legal label (EPA-approved pesticide use instructions), we shouldn’t find produce with pesticide residue exceeding that amount. I don’t think the term “tolerance” is a great one, because I feel like it implies an impact to your health, like how much your body can tolerate. Tolerance is really talking about the maximum anticipated amount of residue on produce. Think of it like a speed limit, only one that you rarely even reach, and even if you go over by a teeny bit, it does not mean certain death. The EPA establishes that level by reviewing extensive registrant-conducted field trials in which the pesticide is sprayed at the maximum labeled rate and the produce is sampled at the shortest interval before harvest. For example, if pest control requires that the pesticide can be sprayed at a maximum of two pounds per acre and no later than seven days before harvest, the field trials will use those conditions. In practice, most farmers will likely not use the full two pounds (pesticides are expensive, they’ll use as little as possible to be effective). The scientists collect all the produce samples from the field trials (done over  one or two seasons throughout the US growing region) and they establish a method to measure the pesticide residue (parent compound plus any metabolites that the pesticide may have been turned into as a result of its interaction with the soil and plant.) The samples are analyzed to determine the concentration of the pesticide residue in the samples collected from all the trials, which may range for example, up to four parts per million (ppm).  Lots of factors affect the residue levels (rainfall, temperature, crop variety, etc.) and they often vary up to 10-fold across all the trials, due to these factors.  The EPA then uses these results in a statistically-based calculation to establish a tolerance, such as five ppm in this example.  The intent is to set a tolerance that is high enough so that it won’t be exceeded if the pesticide was used properly, but is still close to the maximum level measured in the trials.

So now we have the tolerance level (the pesticide shouldn’t occur in the produce above this amount) and the reference dose (people shouldn’t consume more than this in one day.) The only unknown is how much produce do people actually consume? How many apples, for example, do people eat on a daily basis? The EPA uses something called the Dietary Exposure Evaluation Model to figure that out. This database contains survey information for different age groups (infants, young children, teens, elderly, etc.) over different periods of time documenting how much of different foods they ate. The initial dietary risk assessment assumes that everyone is eating the produce for their whole lives that contain residues at the tolerance level. This means that they’re assuming every single acre of apples has been sprayed at the maximum rate and the shortest interval before harvest, and that there is no residue reduction from processing, apples 2-1washing, or cooking. They make the very conservative assumption that every apple you eat has the highest allowable pesticide residue on it, which the USDA knows from the Pesticide Data Program doesn’t happen (more on that in a future article on the Environmental Working Group’s Dirty Dozen List.) Assessments are made for both acute risk (a single day’s consumption) and chronic risk (a lifetime’s consumption). Acute risk assumes that you eat a very large (95th to 99.9th percentile of surveyed consumption) amount of apples in a single day. Chronic risk is based on average daily apple consumption over a lifetime. The amount of apples eaten under both scenarios is multiplied by the tolerance level to give the worst-case pesticide exposure, which is compared to the relevant reference dose (acute or chronic) to determine if the potential exposure is safe (below the reference dose; don’t forget that the reference dose incorporates a 100-1,000 fold safety margin). It’s especially important to note that these dietary risk assessments are not limited to exposure from a single food (e.g., apples) but are for aggregate summed exposure from all approved food uses of that pesticide, plus any potential exposure from drinking water. Total exposure must fall below the relevant reference dose (with its conservative safety margin) before a pesticide can be approved for use.

It’s also important to understand that the decisions of the EPA are legally binding.  It is a federal crime to promote or use a pesticide in any manner that is not approved by the EPA and printed on the label. When a pesticide use is approved, the EPA reviews the exact text of the label that will be printed to describe its proper use, which cannot be changed without prior re-approval.  States also have authority to review and approve pesticide labels. The residue tolerance levels are enacted by the EPA through rule making, and are printed in the Code of Federal Regulations; food containing residues in excess of the tolerance is adulterated and may not legally be sold or distributed. Only after both federal and state approvals of all these documents are complete is a pesticide “registered” for use.

Whew.  See? Not as flippant as you might think.  Not just one or two studies, not conspiracy theories about pesticide companies hiding data, not just someone from the EPA having dinner with someone from the chemical company and shaking hands about money-making over some scotch while they cackle ominously about the fate of our children’s health. I hope no one actually thinks that, but it would make a good caricature for the op-ed section, no? Real scientists doing real studies that actually try to guarantee safety. This is why I feel confident feeding my family conventional produce, and why I’m calling momsense on being afraid of conventional pesticides.

If you’re interested in the real data, and want to follow the registration of a pesticide from start to finish (ala “How a Bill Becomes A Law” only not animated, and not really fun to watch) follow the below progression. I’ve arbitrarily chosen the pesticide fluazinam, which is a broad spectrum contact fungicide often used on potatoes.

  1. Click here to view the CFR entry for fluazinam tolerances
  2. Open the PDF file at this link to see an example of an EPA dietary risk assessment for fluazinam
  3. Click here to see the Federal Register Rule arising from the fluazinam dietary risk assessment
  4. Click here to see the EPA approval of the fluazinam label based on the above decisions
  5. Click here to view the final printed label translating these regulatory actions into a real pesticide use label

* I have to give extensive credit to my dad for helping me with this article. He spent much of his career working on pesticide label registration and has expert experience navigating the regulatory websites and databases.

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