Organic Pesticides Redux

I'm cleaning up a lot of open browser tabs and finishing some blog posts stuck in draft mode limbo.  I may have mentioned that I was elected an executive director for League of Women Voters of Los Angeles County.  My portfolio/niche is to monitor governmental happenings in air/water quality and climate change for LA County.  I am learning a ton, and will share some of what I learn here.

However, I want to make clear that this blog is and will remain a personal blog.  My views do not necessarily reflect those of the LWVLAC as a whole (though I joined them because we have similar views.)

I mentioned in Heavy Metal in LA that our region grapples with unsafe levels of copper in creeks and estuaries.  This led me to learn about the sources of copper.  In this urban environment, it's almost entirely cars and the people who drive them.

Copper-Impaired Waterbodies in the Los Angeles Basin

I mentioned in passing that there are no kale farms nearby and no one took the bait.  Did you know that kale, both organic and conventional, is laden with copper?  Read Organic Pesticides: Not An Oxymoron.  Also look at this Texas A&M extension list of fungicides used in kale production.

All kale gets sprayed--but it is sprayed with different stuff based on how it will be marketed.  According to this list, Copper Hydroxide and Cuprous Oxide is sprayed on organic kale.  Copper Sulfate is sprayed on conventional kale.  Whichever you buy, wash it well, with a bit of detergent to remove residue.

Christie Wilcox wrote in Scientific American blog back in 2012:

In head-to-head comparisons, natural pesticides don't fare any better than synthetic ones. When I compared the organic chemicals copper sulfate and pyrethrum to the top synthetics, chlorpyrifos and chlorothalonil, I found that not only were the organic ones more acutely toxic, studies have found that they are more chronically toxic as well, and have higher negative impacts on non-target species. My results match with other scientific comparisons. In their recommendations to Parliament in 1999, the Committee on European Communities noted that copper sulfate, in particular, was far more dangerous than the synthetic alternative. A review of their findings can be seen in the table on the right (from a recent review paper). Similarly, head to head comparisons have found that organic pesticides aren't better for the environment, either.

I don't know why Wilcox's list and the TAMU list disagree on whether conventional or organic get CuSO4 salt.  Whatever.  In water, the salt breaks down into Cu++ ions and messes up the flora and fauna that grow in and near the water bodies.

I hope we get beyond the organic vs non-organic wars and farm in a sustainable, regenerative way that is healthier for the land, farmers and consumers.

In Sustainable Organic Pesticides, I mentioned that the active ingredients of Neem tree oil can be synthesized in laboratories, which reduces the amount of land and water needed for pest control.  The same is also true for pyrethrins, the active insecticide ingredient in marigolds.

My mother used to grow a border of marigolds around the perimeter of her vegetable garden. I found the odor of the plants unpleasant and frequently felt ill around them. Later, I found out that I am allergic to ragweed and marigolds.  The CDC recommends that "Pyrethrins generally should not be used by persons who are allergic to chrysanthemums or ragweed."

Look up at the table of things that are sprayed on kale. Yup. Organic kale is a transgenic Frankenfood that includes ground up bits of marigolds that can trigger an allergic reaction. I still eat kale, but wash it thoroughly.

Which gets me back to the hysteria about GMOs and the organic wars. The Environmental Working Group's (EWG) Dirty Dozen list comes from their tests for residues of conventional pesticides on produce purchased at a variety of markets and before washing.

EWG does not test for pesticides used in organic farming.  There are a lot of them.

It's not a complete measure of all the risks.  It underestimates the risks by not testing for organic pesticides.  It also overestimates the risk because much of the residue washes off.

EWG rightfully points out that there is wide variation in how thoroughly people wash produce.  Their samples also varied depending on where they bought the produce.  Their measured pesticide load is not your pesticide exposure--it's a proxy that may or may not represent your actual exposure.

I give you another exhibit in organic vs organic wars, the cherry-picked study designed to give you the answer you want. When this article came out, the headlines all echoed "Organic diet intervention significantly reduces urinary pesticide levels in U.S. children and adults."

This is both a 'duh' type study as the conclusion is not surprising, but it's also one that can cause a great deal of stress and anxiety for those that cannot feed their children an 100% organic diet.

The experimental setup and data shows a more nuanced picture.  I want to parse the results to some context.

Firstly, they sought volunteers in neighborhoods that do not have a lot of organic choices and selected volunteers that reported not eating much organic food before the study period.  They followed 16 people in four cities, basically about one family in each city.  This is a very small sample size.

Their urine was tested for a bunch of metabolites of pesticides.  (Chemicals often break down in your body into smaller/related chemicals called metabolites.)

They tested only for pesticides used in conventional farming.  They did not test for any chemicals used in organic farming.  They tested for and found one metabolite that can originate from either organic or conventional pesticides.  More on that later.

It's hard to eat 100% organic when you eat out or don't cook entirely from scratch at home--the way most of us eat.  In this experiment, the researchers did 100% of the shopping and food prep, going as far as delivering meals to the homes of the subjects (and even packing lunches for them to take to work or school.)

Study participants need only heat and serve the prepared meals.  I would have liked the study to give the families organic ingredients and cook their own meals their own way, but I can understand why they didn't.  A study this small can't afford to have any confounding factors like how thoroughly cooks wash produce or whether the water they are washing with already has pesticides in it.

Short of plucking everyone out of their home environments and sequestering them, this was the best way of ensuring that they complied with the strict 100% organic diet.

The results are just what you expected, with a few surprises.  Take a look at the table of detection frequencies (DF).  The DFs went UP for a couple of metabolites/analytes after they switched from a conventional to organic diet!

Detection Frequency of analyzed chemicals in urine samples of test subjects on conventional and 100% organic diets.

However, the concentrations of pesticide metabolites went down overall.  It was quite dramatic (down 95%) for some chemicals, which is reassuring because that means that our bodies quickly expel those chemicals rather than keeping it in our tissues.

Urinary analyte concentrations (ng/mL) & percent change from conventional to organic diet.

This is where the nuance comes in.  The amount of chemicals related to pyrethroid insecticides did not go down as much as for the other chemicals. The authors conjectured that it is because those insecticides are used around the house as well as on crops.

If your kids came home with head lice, you would probably use a product with pyrethroid compounds before the school would allow your child to return.  If you live in tick country, you'd put it on before heading into the woods.

Remember the people who did not have detectable levels of trans-DCCA (a pyrethroid metabolite) when eating a conventional diet but then did have it when eating an organic diet?  That means they did not get exposed to pyrethroid compounds from their homes or their conventional diet.  (Or the levels they had in their urine fluctuated day to day, but their overall level was very low.)

The detection frequencies of trans-DCCA and cis-DCCA went up after switching to the organic diet.  That strongly suggests that they probably got the pyrethroid insecticide exposure from the organic food, not from their homes as the authors suggested.

Read the author statements and the funding source of this study to learn why the experimental design and data interpretation has these flaws.

Whether it is permethrin from a lab or pyrethrin from marigolds, it's hard to avoid some chemicals because of their ubiquity.

BTW, just because something is detectable, doesn't mean it is unsafe.  The reverse is true.  We don't have good tests for some dangerous things.

Once I realized that this is not just a blog where I post pictures of my sewing and knitting projects, I decided to be a voice of reason that and to help dispel the mommy wars.  You are not a bad mommy just because you don't have the time or money to serve your kids 100% organic diets.

I learned this level of detail because I have a BS in Chemistry and am allergic to ragweed.  Whether my veggies are organic or conventional, I wash them (or at least rinse them when in a hurry.)  Am I getting all of it off?  Probably not.  But, perfect is the enemy of done.  As long as I can eat the veggies and not have a sore, scratchy throat afterwards, it's good enough.

It's good to ask questions about your food.  But let's focus on the big picture.  Buy real food, wash it well, eat your veggies.