(image credit: Markus Spiske)
[Maria’s Note: Alison Bernstein, known as Mommy, PhD is my favorite scientist. Heck, I didn’t even know I had a favorite scientist, but Alison opened up this category. Her research is on pesticides so who’s better equipped to talk about the subject than her?
Here’s the deal. Last weekend March Against Monsanto took place. I saw multiple signs saying “Pesticides designed to kill!” What grotesque fear-mongering. Did you know that almost 95% of the pesticides residues in your food is less toxic than the caffeine in your morning coffee?
Probably not. But I’m sure you’ve heard about how scary those pesticides are. Well, Alison examines this in detail today, plus you’ll learn exactly why buying organic is not safer. Enter Alison.]
I never thought much about pesticides and toxic exposures until I was pregnant with our daughter during the great BPA freakout. Then, I obsessed over pesticides and toxic exposures!
It seemed that every mommy blogger was worried and scared. Instead of applying everything I had learned in graduate school about assessing information and data, I fell into the mommy blogger hysteria.
Among other things, we switched to organic, thinking it was pesticide-free and would reduce our exposures. I was a little crazy about it. I knew just enough of the science to freak me out, but not enough to really put it in context.
When our daughter was 1 ½, I joined a toxicology lab and learned actual information about pesticides and stopped worrying about it! My current research focuses on studying the effects of pesticide exposure on the brain and how if affects the risk of neurological diseases.
Even though my work focuses on the effect of pesticides on the brain, I am still not worried about my dietary exposure to pesticides. (It’s really occupational exposure without proper protection and accidental exposures that are the problems). Here’s why:
- The EPA, FDA and USDA regulate pesticide sale and distribution, set safety limit on pesticide residues and enforce these regulations. There is room for improvement and they need more funding to do this properly, especially when it comes to testing organic food.
- Organic food is not safer than conventional. In fact, conventional produce is better tested for pesticide residue than organic.
- Pesticides are not nearly as scary as I thought they were when I started my journey from concerned consumer to educated scientist.
What are pesticides?
Pesticides are anything that kills, well, a pest. They are classified by the types of pests targeted, pesticides include: herbicides, insecticides, rodenticides, insect repellents, fungicides, disinfectants, sanitizer, piscicides, antimicrobials, I think you get the picture!
In general, pesticides that target organisms that are more closely related to us have a greater chance of being toxic to humans (a rodenticide is likely worse for you than an herbicide).
This is because we share more biological pathways in common with organisms that are more closely related to us.
Toxicologists and chemists further classify pesticides by type of chemical. For example, insecticides include organophosphates, organochlorines and ncelrbamates. The type of chemical is informative for understanding the toxicity of a compound, as similar chemicals tend to work by similar mechanisms.
Usually when consumers talk about pesticides, we are only talking about pesticides that are applied to fields and crops and not pesticides that are produced by plants as defense mechanisms against pests (thanks Nurse Loves Farmer).
In short, plants that we consume contain many natural toxins. In fact, scientists estimate that 99.99% of the pesticides we consume are actually chemicals produced by the plants we eat. We have been eating these plants for centuries and don’t worry about them!
So the pesticides we are all worrying about (externally applied pesticides of biological or synthetic origin) represent a tiny fraction of our exposures, which is even more reason not to worry so much.
So from here on, when I talk about pesticides, I’m not talking about pesticides produced by the plants that we eat; I’m referring to externally applied pesticides, whether their origin is biological or synthetic.
Natural vs. Synthetic Pesticides: Irrelevant to toxicity
Pesticides can be classified by their source: synthetic (made in a lab) or biological (what people mean when they say “natural” or “organic”, chemists mean something entirely different when they use the word “organic”). This distinction is meaningless when considering toxicity.
In other words, where a chemical comes from (natural or synthetic) is essentially irrelevant to understanding toxicity.
A good example of this is pyrethroids and pyrethrins. Pyrethrins are compounds produced by chrysanthemums that kill insects by targeting their nervous systems. Pyrethroids are similar compounds produced in a lab to mimic the action of the natural pyrethrins.
The relative toxicities of the compounds in these families have nothing to do with whether they were derived from the plant or in the lab.
How do you know that pesticide residues are below the tolerance level and are actually safe?
There are a number of laws that govern how pesticides are regulated in the US. The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) requires that all pesticides that are sold and distributed in the US must be registered with the EPA (there are specific exemptions for minimum risk pesticides).
Other laws (the Food Quality Protection Act of 1996, the Pesticide Registration Improvement Act of 2003, the Pesticide Registration Improvement Renewal Act of 2007 and the Pesticide Registration Improvement Extension Act of 2012) have amended this process.
Under these laws, new pesticides need to be registered before the can be sold and distributed. Existing pesticides must be reevaluated every 15 years to incorporate new data and ensure that they continue to meet current safety standards. All pesticides registered prior to the introduction of the Food Quality Protection Act in 1996 were also reassessed.
What is pesticide registration?
From the EPA (United Stated Environmental Protection Agency):
“The process of registering a pesticide is a scientific, legal, and administrative procedure through which we examine the ingredients of the pesticide; the particular site or crop where it is to be used; the amount, frequency, and timing of its use; and storage and disposal practices.”
The key information for a consumer is that a pesticide can only be registered for use on food or animal feed by the EPA if the results of the risk assessment show “reasonable certainty of no harm.”
You can check the status of the registration of any pesticide on this website.
How does the EPA determine whether a pesticide is safe to use?
The EPA evaluates the potential for pesticides to affect both human health and ecology in three categories.
- Ecological risk assessment: an examination of the potential hazard to non-target plants, fish, and wildlife species
- Human health risk assessment: an estimate of the nature and probability of adverse health effects in humans exposed to pesticides in contaminated environments (not occupational exposures)
- Pesticide cumulative risk assessment: This is a newer category that was added in 1996 by the Food Quality Protection Act. This evaluates the risk posed by concurrent exposures to chemicals that act by similar mechanisms.
In these assessments, the EPA considers data from studies provided by the company applying for registration, as well as studies in the scientific literature. To be included, studies must meet standards set by the EPA.
After this process, the EPA determines appropriate guidelines for the use of the pesticide to ensure that exposures remain low enough to avoid an increased risk of adverse effects. This process also involves the approval of the labels to ensure that the directions for use and safety measures are in agreement with the EPA’s risk assessment.
More specific details about these assessments and the guidelines for inclusion of studies can be found on the EPA risk assessment website.
What are “tolerances”?
According to the Federal Food, Drug and Cosmetic Act (FFDCA), as part of the human health risk assessment, the EPA must set limits (known as tolerances in the US) for all pesticides used on food.
In many other countries, these are called maximum residue limits (MRLs). Tolerances apply to imported food, as well as food grown in the US.
A tolerance is the maximum amount of pesticide residue safely allowed in or on human food or animal feed. There is a particular focus in determining these tolerances on protecting infants and children.
How does the EPA set pesticide tolerances?
From the EPA:
“EPA establishes tolerances for each pesticide based on the potential risks to human health posed by that pesticide. Some risk assessments are based on the assumption that residues will always be present in food at the maximum level permitted by the tolerance.
Other risk assessments use actual or anticipated residue data, to reflect real-world consumer exposure as closely as possible.”
The dose that is set as the tolerance is called the reference dose (RfD). The RfD is the estimate of the daily oral exposure to humans that is likely to be without appreciable risk of deleterious effects throughout the entire lifetime.
In other words, it is the amount of the pesticide that you could be exposed to every single day of your life without any adverse effect attributed to that pesticide.
The FDA and USDA test food to make sure pesticide residues are below these limits. Tolerances for non-organic food are enforced by the USDA (meat, poultry and eggs) and FDA (other food items)
The Pesticide Data Program is the USDA program that collects data on pesticide residues in food. The Pesticide Monitoring Program is the FDA counterpart. This information regarding actual residues is used in EPA risk assessments for re-registrations.
If residues are found above a tolerance, enforcement actions are triggered. This are handled by the FDA, regardless of whether the violation is found by the USDA or FDA program.
In 2014, the Government Accountability Office reviewed the pesticide monitoring programs at USDA and FDA. Overall, the findings were positive and they found that for the produce tested, 95% or more samples were not in violation of the tolerance.
The GAO did issue recommendations for improvements to the programs, including increased sampling and improved statistical modeling to generate more accurate estimates of residues and to test more for pesticides on more products (the list is prioritized based on the risk level and usage).
Of course, implementing these recommendations also requires more funding, which has clearly been a problem across the board in the US these days.
Despite recognizing these areas of improvement, the GAO report was mostly positive and found that the USDA and FDA have found very few incidences of violations of tolerances and have found residue levels well below tolerance levels.
But what about organic?
Organic food not safer than conventional.
First, “safer” implies that non-organic produce is somehow “unsafe” (it’s not unsafe). Second, despite what organic companies want you to believe, organic does not mean pesticide free. And third, the pesticides employed in organic farming are not necessarily safer.
Organic produce is less tested compared to non-organic produce.
An important caveat to this is that these programs largely test for pesticides that are not used in organic farming, with a few exceptions. Exceptions may include organic-approved pesticides that are also used in non-organic farming. Yes, organic farming uses pesticides and they even use some non-organic pesticides (the list of approved substances for organic farming can be found on the National List of Allowed and Prohibited Substances for the National Organic Program). This use of both organic and synthetic pesticides in organic farming has been discussed here.
The USDA and FDA monitoring programs focus on non-organic produce, not because organic is excluded, but because organic is such a small part of the produce market compared to non-organic.
When they prioritize the pesticides to test for, synthetic pesticides are higher on the list because more people eat non-organic produce.
Because of this disparity in testing, when the National Organic Program was established in 2000, this included a requirement that the program set up residue testing for organic pesticides on organic produce.
However, a 2010 audit of the program by the Office of the Inspector General found that the program did not establish residue testing for organic produce, among other issues with compliance enforcement procedures.
In response, the NOP implemented residue testing in 2013. However, this program only tests for the presence of pesticides prohibited by the NOP. They do not appear to be testing for residues of allowed substances.
Therefore, while this testing is useful for identifying violations to the organic certification process, it is not at all useful for assessing the possible exposures to pesticide residues on organic produce.
This point is critical when you consider that organizations that create lists of “safe” produce (like the Environmental Working Group or Consumer Reports) they are using only the FDA and USDA data that is only testing for non-organic pesticides.
A real list would compare residues on non-organic and organic produce and compare the toxicity of those residues. However, there is little to no data about pesticide residues on organic produce for pesticides actually used in organic farming to make that comparison.
While you may see news reports stating that pesticide exposure goes down when people switch to an organic diet, be aware that all such reports look only selected pesticides (used only in non-organic farming). Without knowing what we are trading it for, we cannot say that organic is safer overall. So if you thought that organic food is safer than conventional, well now you know it’s not true. So if you thought that organic food is safer than conventional, well now you know it’s not true.
We using less pesticides, they’re also getting safer and safer
The fact that pesticides residues on food are regulated, tested, and at the end of the day, not as scary as we thought doesn’t mean we shouldn’t do better with pesticides. And we are actually doing just that.
Since the 1970s we have actually done a good job of switching to safer pesticides – they are less persistent in the human body and the environment and are more effective at lower doses. This doesn’t mean we can’t still improve, but we need to acknowledge that we have come a long way.
Part of the switch to safer pesticides has come from the EPA’s reevaluation old pesticides that were used before these new laws went into effect (and the new laws require the EPA to reevaluate each pesticide every 15 years.)
This has resulted in the registrations for old pesticides being cancelled. This allows the EPA to update pesticide registrations based on new data.
The Stockholm Convention on Persistent Organic Pollutants has also played an important role in eliminating the production and use of the worst chemicals in agriculture and industry. I wrote about this in our previous post about whether you need to worry toxicants in our food.
Modern farming techniques have reduced pesticide use
Pests are an unavoidable part of farming. The best way to reduce pesticide use is to employ the best of all available technologies in a comprehensive system of pest management.
Pesticides are just one aspect of effective pest management. An effective pest management strategy includes the use of genetically engineered crops (GMOs), crop rotation, cover crops and the appropriate timing of pesticide application.
I spoke to Kelly, a farm wife and mom who blogs at Daddy’s Tractor. Kelly has written about these approaches employed on her family’s (non-organic) farm to protect the environment and reduce pesticide use.
- Crop rotation reduces pesticide use so that an insect that thrives on one crop struggles in the “off” season to live on a different crop.
- Cover crops means planting grasses or other crops between growing seasons to discourage pests, in particular nematodes. Using cover crops has benefits besides suppressing weeds, including replenishing organic matter into the topsoil and pulling nutrients up from the ground into the soil.
- The timing of pesticide application can also reduce pesticide use. In particular, spraying soybeans later in the growing season allows beneficial bugs the chance to become established.
GMO crops reduce pesticide use
Some people find this controversial, so let’s talk a bit about what the data shows.
A recent meta-analysis showed that use of genetically engineered crops on average “reduced chemical pesticide use by 37%, increased crop yields by 22%, and increased farmer profits by 68%.” This is discussed in more detail at GMOAnswers.com: here and here. The second article provides a summary of data from the USDA.
Insecticide use in corn is down 18-fold from 2000 to 2010. In cotton it is down 6-fold over the same time period. This time period coincides with the introduction of GM corn and cotton for insect management.
Herbicide use in corn and soybeans peaked in 1982. There has been small increase in the past 10 years, but levels are still much lower than they were.
Fungicide usage has remained approximately steady over the years, and GM crops have yet to be introduced to resist plant disease and reduce the need for fungicides.
[Maria’s Note: For more on GMOs you can also check out my article detailing 10 Reasons I’m Grateful for GMOs]
Despite this low risk to you as a consumer, reducing pesticide use is beneficial for the environment, sustainable farming practices and safety for farmers. Reducing pesticide use requires using ALL available safe technologies: genetically engineered crops, newer less persistent pesticides and adopting practices like crop rotation, cover crops and properly timed pesticide application. Nothing is risk free, but regulations have greatly lowered dietary exposures to pesticide on both organic and non-organic produce. Scientists and regulators must continue to work to reduce impacts for the environment and for people who are occupationally exposed.
For more information, the EPA Pesticides page contains more detailed information on the topics discussed here, regarding including health and safety assessments, environmental effects, regulations, and compliance and enforcement.
Organic food not safer, so why not invest in buying MORE (conventional) fruits and vegetables?
As a consumer, the important thing to know is that pesticide residues (as tested by the FDA and USDA) on produce is so far below the tolerances set by the EPA that you really have very little to worry about!
And there is no need to spend more on organic. As I mentioned above, organic is not “safer” than conventional. Buying organic does not necessarily reduce your exposure to pesticide residues but we really have no data on what is actually going on with pesticide residues on organic produce as they are not as vigorously tested.
In fact, with the money you save by not buying organic, you can buy more fruits and vegetables, which is an undisputed, really good thing for your overall health.
My kids just love berries. When we stopped buying organic produce, we could buy more than double the berries for the same price. Now they can eat all the berries they want and we don’t feel like we have to limit their fruit intake because of the price.
A new study published in October 2016 showed that fear-based and fact-light food marketing about pesticides leads people to purchase fewer fruits and vegetables. This is particularly true for low-income shoppers. It has little effect on those who can afford to pay the premium for organic produce, as they just reach for a more expensive but equally safe and nutritious alternative. For those on a budget, however, this fear leads them to avoid purchasing fruits and vegetables altogether.
The benefit of a diet high in fruits and vegetables far outweighs any of the risk posed by pesticide residues on produce. In other words, even if pesticide residues on produce do pose a risk to health, that risk is far outweighed by the benefits of a diet rich in fruits and vegetables. In addition, we also know that the risks of toxic exposures are greater in groups that also have poor diet. Improving diet through the consumption of more fruits and vegetables, whether they are organic or not, may help to mitigate the effects of these exposures across the board by improving overall health.
UPDATE: Revised December 12, 2016 to reflect that some organic pesticides are sometimes included in the Pesticide Data Program and Pesticide Monitoring Program, to address reports of reduced pesticide exposure upon switching to an organic diet and to discuss recent studies on the effects of fear-based marketing about pesticides.
So how do you feel about pesticides? Leave a comment below!